sediment impairment in the goose creek watershed ... · habitat (wah). because the water quality in...

Project Final Report

for

A Grant Awarded Through the Section 319(h) Nonpoint Source

Implementation Program Cooperative Agreement

#C9994861-05

under the

Section 319(h) Kentucky Nonpoint Source Implementation

Grant Workplan “Geomorphic Assessment & Watershed

Implementation Plan for a Sediment Impaired Watershed”

Kentucky Division of Water NPS 05-08

MOA PO2 0600000476

January 1, 2006 to September 30, 2011

Sediment Impairment in the Goose Creek Watershed: Assessment Findings and Potential Management Strategies

Michael A. Croasdaile Arthur C. Parola, Jr.

of The Stream Institute Department of Civil and Environmental Engineering University of Louisville Louisville, Kentucky

The Energy and Environment Cabinet (EEC) and the University of Louisville Research Founda-tion, Inc., (a KRS164A.610 corporation) do not discriminate on the basis of race, color, national origin, sex, age, religion, or disability. The EEC and the University of Louisville Research Foundation, Inc., will provide, on request, reasonable accommodations including auxiliary aids and services nec-essary to afford an individual with a disability an equal opportunity to participate in all services, pro-grams and activities. To request materials in an alternative format, contact the Kentucky Division of Water, 200 Fair Oaks Ln, Frankfort, KY 40601 or call (502) 564-3410 or contact the University of Lou-isville Research Foundation, Inc.

Funding for this project was provided in part by a grant from the US Environmental Protection Agency (USEPA) through the Kentucky Division of Water, Nonpoint Source Section, to the University of Louisville Research Foundation, Inc., as authorized by the Clean Water Act Amendments of 1987, §319(h) Nonpoint Source Implementation Grant #C9994861-05. Mention of trade names or com-mercial products, if any, does not constitute endorsement. This document was printed on recycled paper.

iii

Acknowledgements

Michael A. Croasdaile, PhD, Assistant Professor of Civil and Environmental Engineering (CEE) at the University of Louisville, was the principal investigator for this project and directed the collection and analysis of stream geomorphic data and the development of watershed management strategies.

Arthur C. Parola, Jr., PhD, PE, Professor of CEE and Director of the Stream Institute (ULSI), provided technical advice regarding data collection, analysis, and interpretation.

Chandra Hansen, ULSI Research Technical Writer, contributed to the writing of the report and edited the final report.

Mark N. French, PhD, PE, Professor of CEE, provided technical advice regarding data collection and analysis.

Clayton Mastin, MEng, ULSI Research Project Engineer, conducted the pond survey data collection. CEE students Dempsey L. Ballou, J Brandon Kolze, C. Davis Murphy, J. Duncan Gatenbee, Hannah R.

Gill, and Erin E. Cummings assisted with data collection and GIS analysis. Michael H. Borchers as-sisted with data collection and conducted analysis of pond survey data. Danielle Dresch contributed to the data analysis.

Margi Swisher Jones, [former] Technical Advisor for the Kentucky Nonpoint Source Pollution Control Program, Kentucky Division of Water, provided project oversight and technical guidance throughout the course of the project

We greatly appreciate the willingness of numerous landowners throughout Goose Creek and Benson Creek watersheds to provide access to their land for sampling or surveys.

v

Contents

List of Figures and Tables ............................................................................................................................vi Executive Summary .....................................................................................................................................ix 1 Introduction ........................................................................................................................................... 1

2 Materials and Methods ......................................................................................................................... 3 2.1 Project Area .................................................................................................................................. 3 2.2 Study Design ............................................................................................................................... 12 2.3 Remote Watershed Assessment .................................................................................................. 13 2.4 Field Assessment ........................................................................................................................ 14 2.5 Monitoring Site Selection ........................................................................................................... 23 2.6 Monitoring Data Collection ........................................................................................................ 27 2.7 Monitoring Data Analysis ........................................................................................................... 31

3 Results and Discussion........................................................................................................................ 38 3.1 Watershed Geomorphic Characteristics ...................................................................................... 38 3.2 Sediment Production and Storage ............................................................................................... 49 3.3 Suspended Sediment Loads ........................................................................................................ 63 3.4 Assimilative Capacity ................................................................................................................. 66

4 Conclusion ........................................................................................................................................... 67 4.1 Sources, Embeddedness, and Water Quality Goals .................................................................... 67 4.2 Management Strategy Recommendations ................................................................................... 70 4.3 Impairment Reduction Estimates ................................................................................................ 71 4.4 Strategies for Reducing Goose Creek Sediment Yields .............................................................. 73 4.5 Project Measures of Success ....................................................................................................... 77 4.6 Lessons Learned and Recommendations .................................................................................... 78

References ................................................................................................................................................... 81 Appendices .................................................................................................................................................. 85

A Financial and Administrative Closeout ....................................................................................... 87 B Quality Assurance Project Plan (QAPP) ..................................................................................... 89 C BMP Reach Summaries ............................................................................................................ 115

vi

Figures and Tables

FIGURES Figure 2.1 Goose Creek watershed and 303(d)-listed stream reaches. ................................................... 5 Figure 2.2 Confluence of Benson Creek and the Kentucky River during a flood event. ....................... 5 Figure 2.3 Geological map of Goose Creek watershed. ......................................................................... 6 Figure 2.4 Rock cut showing Clays Ferry Formation and friable shale. ................................................ 7 Figure 2.5 Rock cut showing Tanglewood Limestone Member. ........................................................... 7 Figure 2.6 Distribution of soil types within Goose Creek watershed. .................................................... 8 Figure 2.7 Land cover in Goose Creek watershed. ............................................................................... 10 Figure 2.8 Monthly temperature and precipitation. .............................................................................. 11 Figure 2.9 Assessed blue-line reaches in the Goose Creek watershed. ................................................ 16 Figure 2.10 Locations of bank erosion monitoring sites. ....................................................................... 23 Figure 2.11 Locations of ponds surveyed in the Benson Creek watershed. ........................................... 25 Figure 2.12 Suspended sediment sampler locations in the Goose Creek watershed. ............................. 27 Figure 2.13 Suspended sediment sampler near Goose Creek and Benson Creek confluence. ............... 29 Figure 2.14 Suspended sediment sampler at Goose Creek near I-64. .................................................... 29 Figure 3.1 Spatial distribution of embeddedness.................................................................................. 41 Figure 3.2 Blanket covering of riffle sediments with silt, Ballard Branch. .......................................... 42 Figure 3.3 Blanket covering of riffle sediment with sand, Ballard Branch. ......................................... 43 Figure 3.4 Cobble bed with silt intrusion, Ballard Branch. .................................................................. 43 Figure 3.5 Cobble bed with silt intrusion, Ballard Branch. .................................................................. 44 Figure 3.6 Cobble bed with interstices filled with sand, Ballard Branch. ............................................ 44 Figure 3.7 Siltation can aggravate and be aggravated by growth of algae. .......................................... 45 Figure 3.8 Spatial distribution of epifaunal substrate quality. .............................................................. 45 Figure 3.9 Spatial distribution of flow status. ...................................................................................... 46 Figure 3.10 Spatial distribution of sediment deposition. ........................................................................ 46 Figure 3.11 Spatial distribution of velocity/depth combinations. .......................................................... 47 Figure 3.12 Distribution of hydrological condition in Benson Creek watershed. .................................. 48 Figure 3.13 (a) North Fork North Benson Creek and (b) Benson Creek. ............................................... 49 Figure 3.14 Line of erosion showing where weathered material had been removed. ............................ 51 Figure 3.15 Empirical relationships between erosion rates and BEHI ranking for Goose Creek

watershed. ........................................................................................................................... 52 Figure 3.16 Typical bank composition in the Goose Creek watershed. ................................................. 53 Figure 3.17 Generated drainage network using the minimum surveyed channel head area. ................. 56 Figure 3.18 Generated drainage network using the maximum surveyed channel head area. ................. 56 Figure 3.19 Generated drainage network using the mean surveyed channel head area. ........................ 56 Figure 3.20 Sediment yields modeled using GeoWEPP for individual hillsides. .................................. 61 Figure 3.21 The upland erosion rate estimated from the pond surveys compared to the

sediment yield predicted for the same hillslope using GeoWEPP.. .................................... 62 Figure 3.22 Relationship between suspended sediment concentration and stage................................... 64 Figure 3.23 Relationship between suspended sediment concentration and discharge. .......................... 65

Figures and Tables vii

Figure 4.1 Deposition of fine sediment permits in-channel vegetation growth that promotes further trapping of fine sediment......................................................................................... 68

Figure 4.2 This small tributary supplies sediment to Goose Creek downstream of Ballard Branch confluence following small storms when the velocities in the main stem are low enough for sediment to deposit on riffles. .............................................................. 68

Figure 4.3 Debris jams (either formed accidentally or by beavers) cause reduced flow velocities upstream of the obstruction and can cause temporary embeddedness of riffles and filling of pools. ................................................................................................... 69

Figure 4.4 Blue-line channel reaches identified as particularly suitable for implementation of BMP strategies to reduce embeddedness in Goose Creek watershed. ................................ 72

Figure 4.5 Pre- and post-settlement valley configurations. .................................................................. 74 Figure 4.6 Exposed tree roots were observed along most reaches in Goose Creek and could

potentially provide useful information on erosion rates averaged over a number of years, integrating the effects of years of low and high rainfall. .......................................... 79

Figure 4.7 Exposed tree roots can provide information on erosion rates even at very small drainage areas. ..................................................................................................................... 80

TABLES Table 1.1 USEPA Criteria to Award CWA Section 319 Nonpoint Source Grants to States

and Territories ....................................................................................................................... 2 Table 2.1 CWA Section 303(d) Impaired Water Bodies, Benson Creek Watershed ............................ 4 Table 2.2 Goose Creek Watershed Soils ............................................................................................... 8 Table 2.3 Goose Creek Watershed Land Use ....................................................................................... 9 Table 2.4 Precipitation Extremes ........................................................................................................ 11 Table 2.5 Length of Growing Season ................................................................................................. 11 Table 2.6 Summary of Source Assessment Methods .......................................................................... 12 Table 2.7 Assessed Blue-Line Stream Reaches .................................................................................. 15 Table 2.8 RBP Sub-Reach-Scale Parameters ...................................................................................... 17 Table 2.9 RBP Reach-Scale Parameters ............................................................................................. 18 Table 2.10 BEHI Risk Ratings and Parameters .................................................................................... 20 Table 2.11 NBS Risk Ratings and Parameters ...................................................................................... 20 Table 2.12 Assessed Ponds ................................................................................................................... 24 Table 2.13 Locations of Sedimentation Mats........................................................................................ 26 Table 2.14 Suspended Sediment Monitoring Sites ............................................................................... 26 Table 2.15 Deposition Categories ......................................................................................................... 36 Table 3.1 Riffle Crest-to-Crest Distances ........................................................................................... 40 Table 3.2 Distribution of RBP Sub-Reach-Scale Parameter Scores ................................................... 47 Table 3.3 Annual Erosion Rates for Blue-Line Assessment Reaches ................................................. 50 Table 3.4 Summary of Erosion Pin Results ........................................................................................ 51 Table 3.5 Correlation Matrix of BEHI Parameters ............................................................................. 52 Table 3.6 Sediment Produced by Blue-Line Stream Bank Erosion in Goose Creek Watershed ........ 54 Table 3.7 Estimated Length of Goose Creek Watershed Channel Network ....................................... 55 Table 3.8 Unit Mass Erosion and Annual Load Summary for Unmapped Channel Reaches ............. 57 Table 3.9 Unit Mass Erosion: First-Order Unmapped Channel Reaches ............................................ 57 Table 3.10 Unit Mass Erosion: Second-Order Unmapped Channel Reaches ....................................... 58 Table 3.11 Upland Sediment Production Rates Estimated from Pond Sediments ................................ 61 Table 3.12 Upland Sediment Production Rates Estimated from GeoWEPP ........................................ 61 Table 3.13 Sediment Deposition Rates ................................................................................................. 63 Table 3.14 Suspended Sediment Concentrations from US U-59 Samplers .......................................... 63 Table 3.15 Estimated Event and Annual Suspended Sediment Loads .................................................. 65

viii Sediment Impairment in the Goose Creek Watershed

Table 3.16 Summary of Annual Sediment Production, Storage, and Yield Masses in Goose Creek Watershed ................................................................................................................. 65

Table 3.17 Estimated Sediment Mass Required to Embed Riffles by 50 Percent ................................ 66 Table 4.1 Embedded Riffles in Goose Creek Watershed and Estimated Impairment

Reductions Due to BMP Implementation ........................................................................... 72

ix

Executive Summary

Stream sedimentation, the process of deposition of sediment or other material on the channel bed, is one of the most common causes of stream impairment in the United States and in the Commonwealth, where “sedimentation/siltation” and other sediment-based pollutants (i.e., solids (suspended/ bedload), turbidity, and total suspended solids) and pollution (i.e., particle distribu-tion/embeddedness, physical substrate habitat alterations, and bottom deposits) are cited as the cause of impairment for the majority of the streams listed as impaired for warm water aquatic habitat (WAH). Because the water quality in these sediment-impaired streams does not support their designated use, the Commonwealth is required under Section 303(d) of the Clean Water Act to establish watershed pollution management strategies that will be effective in reducing the impairment.

The purpose of this project was to develop a watershed implementation plan (WIP) to reduce sedimentation/siltation in a First Priority 303(d)-listed stream or a stream where a TMDL is un-der development. The project had two goals and objectives. The first goal was to quantify the sediment impairment and determine the load reduction or impairment reduction necessary using a watershed-scale and reach-scale geomorphic assessment. The second project goal was to de-scribe management strategies and specific activities (BMP implementation) that would be eco-nomically and morphologically sustainable and necessary to achieve estimated reductions.

A geomorphic source assessment was completed for Goose Creek watershed, an impaired sub-watershed of Benson Creek in central Kentucky. Field observations of the Goose Creek main stem, tributary channels, and their valleys were used to identify to identify sources of sediment production, floodplain storage areas, and potential reference reaches. The effects of geology, his-torical land-use, and current land use on sediment loads and channel evolution were also consid-ered in the assessment. In-stream transport of sediment and locations identified as sources of sed-iment production or areas of floodplain deposition were monitored throughout the watershed for approximately 12-14 months in 2007 and 2008. Sediment deposits in selected pond sites also were measured. These monitoring data were analyzed to quantify sediment loads and identify which sediment sources and sedimentation processes within the Goose Creek watershed were the greatest contributors to embeddedness, the indicator used to quantify the sediment impairment.

No reference-quality reaches were identified in Goose Creek watershed. All reaches that were assessed showed significant signs of alteration, and the channels’ sediment capacity and loads have greatly increased relative to pre-settlement conditions. Sediments from upland erosion were the largest component of the annual sediment mass supplied to the channels. Although sed-iments from bank erosion accounted for the remaining one-quarter of the annual supply, bank erosion rates were relatively low. Stream banks are primarily composed of cohesive silt and clay that limit the erosive effects of flood flows; erosion of these soils is primarily a consequence of weathering rather than boundary shear stress from flows.

x Sediment Impairment in the Goose Creek Watershed

Analysis of the geomorphic assessment and monitoring data showed that embedded riffles were the result of both proximity to the local sediment supply and the local flow conditions at the riffle at the time the sediment was supplied. The most severely embedded riffles in non-backwater locations were those where sediment was supplied to the riffle when flow was barely above the riffle crest elevation. The feasibility of modifying those local conditions was the basis for estimating the potential for reductions in sediment impairment in the watershed. Potential nonpoint source (NPS) management strategies such as overland erosion control, stream restora-tion, and bank stabilization were evaluated based on estimates of impairment reduction that could be expected as a result of implementation of each strategy. The technical resources neces-sary for implementation of each strategy were identified, and approximate costs were estimated. These estimates and recommendations will support KDOW’s development of sediment total maximum daily loads (TMDLs) for Benson Creek watershed.

1

Sediment Impairment in the Goose Creek Watershed: Assessment Findings and Potential Management Strategies

By Michael A. Croasdaile and Arthur C. Parola, Jr.

1. Introduction

Stream sedimentation, the process of deposition of sediment or other material on the channel bed, affects aquatic communities by choking spawning gravels, impairing food sources, and reducing habitat complexity (USEPA 1999). It is one of the most common causes of stream impairment in the United States (USEPA 2000) and in the Commonwealth (KDOW 2007), where “sedimentation/siltation” and other sediment-based pollutants (i.e., solids (suspended/ bedload), turbidity, and total suspended solids) and pollution (i.e., particle distribution/embeddedness, physical substrate habitat alterations, and bottom deposits) are cited as the cause of impairment for 69 percent (2735 miles) of the streams listed as im-paired for warm water aquatic habitat (WAH). Because the water quality in these sediment-impaired streams does not support their designated use, the Commonwealth is required un-der Section 303(d) of the Clean Water Act to establish pollution management strategies that will be effective in reducing the impairment.

Sedimentation tends to be instigated by nonpoint sources and can be a product of sever-al factors: sediment supply in excess of transport capacity, inadequate sediment filtering by floodplains, and/or uniform in-channel deposition promoted by incised and entrenched channels. Therefore, watershed-scale best management practices (BMPs) that will be effec-tive for meeting water pollution standards require not only that the sediment load be quanti-fied but also that the specific sources be identified and the links between the sources, the loads, and the impairment be confirmed and evaluated. To sufficiently assess and quantify water pollutant loads being contributed from different sources within the watershed, several questions must be addressed (USEPA 1999): What are the relative contributions of different sediment sources in the watershed? How should sediment sources be grouped? How wide-spread is the sedimentation: is it restricted to specific areas or reaches? Are other water qual-ity impairments or physical impairments contributing to the problem?

Few sediment source studies have been completed in Kentucky. Some suspended sedi-ment data have been systematically collected (Crain 2001; Williamson and Crawford 2011), and they are useful as reference measurements of suspended sediments. Although identifica-tion of sources was not a goal of those projects, the data collected to provide background, or natural, levels of pollutants in large Kentucky rivers did support estimates of loads and yields of suspended sediments and other pollutants. A study of South Elkhorn Creek in the Inner Bluegrass physiographic sub-region (Fox et al. 2010) and Curry’s Fork in the Outer

2 Sediment Impairment in the Goose Creek Watershed

Bluegrass (Croasdaile and Parola 2011) may be the only studies to date in Kentucky that identified sediment sources. The applicability of the South Elkhorn study’s findings to other watersheds in the physiographic region will be uncertain until additional data has been col-lected for comparison. The Curry’s Fork study found that upland surface erosion was the main source of sediment in the watershed.

The purpose of this project was to develop a watershed implementation plan (WIP) to reduce sedimentation/siltation in a First Priority 303(d)-listed stream or a stream where a TMDL is under development. The project had two goals and objectives. The first goal was to quantify the sediment impairment and determine the load reduction or impairment reduc-tion necessary using a watershed-scale and reach-scale geomorphic assessment. This goal was designed to comply with Criterion 3a, the first of nine project elements (Table 1.1) de-fined by USEPA (2002) guidelines as critical to development of WIPs to reduce nonpoint source (NPS) pollution in impaired waters. The objective established to meet this goal was to conduct a pilot geomorphic assessment of a sediment-impaired watershed using protocols and GIS extensions developed by the Vermont Agency of Natural Resources (VTANR) for watershed-scale geomorphic assessment (VTANR 2004). The geomorphic assessment was completed for Goose Creek watershed, an impaired sub-watershed of Benson Creek in cen-tral Kentucky. In-stream transport of sediment and locations identified as sources of sedi-ment production or areas of deposition were monitored throughout the watershed for

Table 1.1 USEPA (2002) Criteria to Award CWA Section 319 Nonpoint Source Grants to States and Territories

Criterion 3: Elements to be Included in Watershed Implementation Plans for 303(d)-listed Waters a. An identification of the causes and sources or groups of similar sources that will need to be controlled to

achieve the load reductions estimated in this watershed-based plan (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in item (b) immediately below.

b. An estimate of the load reductions expected for the management measures described under paragraph (c) below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time).

c. A description of the NPS management measures that will need to be implemented to achieve the load reductions estimated under paragraph (b) above (as well as to achieve other watershed goals identified in this watershed-based plan), and an identification (using a map or a description) of the critical areas in which those measures will be needed to implement this plan.

d. An estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, to implement this plan.

e. An information/education component that will be used to enhance public understanding of the project and encourage their early and continued participation in selecting, designing, and implementing the NPS man-agement measures that will be implemented.

f. A schedule for implementing the NPS management measures identified in this plan that is reasonably expeditious.

g. A description of interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented.

h. A set of criteria that can be used to determine whether loading reductions are being achieved over time and substantial progress is being made towards attaining water quality standards and, if not, the criteria for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been estab-lished, whether the NPS TMDL needs to be revised.

i. A monitoring component to evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under item (h) immediately above.

Introduction 3

approximately 12-14 months in 2007 and 2008, and the monitoring data were analyzed to quantify sediment loads and identify which sources of sediment within the Goose Creek wa-tershed were the greatest contributors to embeddedness, the indicator used to quantify the sediment impairment. The geomorphic assessment and monitoring data were used to esti-mate the feasible reduction in embeddedness throughout the watershed.

The second project goal was to describe management strategies and specific activities (BMP implementation) that would be economically and morphologically sustainable and necessary to achieve estimated reductions. This goal addressed USEPA (2002) Criteria 3b through i (Table 1.1), with a primary focus on Criteria 3b and c. The objective established to meet this goal was to develop an effective watershed management strategy to reduce sedi-ment load or sediment impairment. Potential NPS management strategies such as overland erosion control, stream restoration, and bank stabilization were evaluated based on estimates of impairment reduction that could be expected as a result of implementation of each strate-gy. The technical resources necessary for implementation of each strategy were identified, and approximate costs were estimated. These estimates and recommendations will support KDOW’s development of sediment total maximum daily loads (TMDLs) for Benson Creek watershed.

2. Materials and Methods

2.1 PROJECT AREA

Goose Creek, located approximately 6 mi west of Frankfort in Shelby County, Ken-tucky, drains an area of 10.32 mi2. It is a tributary of Benson Creek (HUC 05100205), which has a drainage area of about 100 mi2 at its confluence with the Kentucky River at Frankfort. Designated uses for surface waters and numeric and narrative criteria to protect those uses are set forth in Kentucky Administrative Regulations (KAR). The designated uses of Goose Creek and Benson Creek are warm water aquatic habitat, primary contact recreation, and secondary contact recreation (401 KAR 10:026 §5(2)(a)). No numeric criteria have been adopted for sediment as a pollutant. Narrative criteria relevant to sediment impairment re-quire that

Surface waters shall not be aesthetically or otherwise degraded by substances that: (a) Settle to form objectionable deposits; (b) Float as debris, scum, oil, or other matter to form a nuisance; (c) Produce objectionable color, odor, taste, or turbidity; (d) Injure, are chronically or acutely toxic to or produce adverse physiological or

behavioral responses in humans, animals, fish, and other aquatic life; (e) Produce undesirable aquatic life or result in the dominance of nuisance species;

(401 KAR 10:031(2)) WAH impairments (Table 2.1) have been documented for approximately 21 river miles

of streams in the Benson Creek watershed, including 4.2 river miles of Goose Creek (Fig-ure 2.1). In-channel deposition of fine-grained sediment is widespread in both watersheds, and Benson Creek has been the source of many public comments regarding high turbidity (Margi Jones, pers. comm.): following heavy rain, the confluence of Benson Creek with the Kentucky River often shows turbid water coming from Benson Creek watershed (Fig-ure 2.2), and a plume of turbid water from Goose Creek has been observed in Benson Creek


after rainfall events. Sediment data collected prior to this project in 2000-2004 (KDOW 2004) indicated that silt and clay were the sediments contributing to the sedimenta-tion/siltation impairment. KDOW completed monitoring of nutrients, organic enrichment, and total suspended solids (TSS) for the listed Benson Creek watershed segments in 2004 (KDOW 2004).

Table 2.1 CWA Section 303(d) Impaired Water Bodies, Benson Creek Watershed (KDOW 2010)

Stream Name County River Miles

Impaired Use Pollutant Suspected Sources

Benson Cr. into Kentucky R.

Franklin 0.0 to 4.6

WAH (partial)

Sedimentation/ Siltation Agriculture; Habitat Modification - other than Hydromodification

4.6 to 6.7

WAH (partial)

Nutrient/ Eutrophication Biological Indicators

Agriculture, On-Site Treatment Systems (Septic Systems and Similar Decentral-ized Systems)

Sedimentation/ Siltation Agriculture, Habitat Modification - other than Hydromodification, High-way/Road/Bridge Runoff (Non-Construction Related)

6.7 to 13.4

WAH (nonsupport)


Agriculture

Sedimentation/ Siltation Agriculture; Habitat Modification - other than Hydromodification; High-way/Road/Bridge Runoff (Non-construction Related)

Goose Cr. into Benson Cr.

Shelby 0.0 to 1.8

WAH (partial)

Sedimentation/ Siltation Agriculture; Habitat Modification - other than Hydromodification; High-way/Road/Bridge Runoff (Non-construction Related)

1.85 to 4.2

WAH (partial)

Cause Unknown Agriculture; Grazing in Riparian or Shoreline Zones; Livestock (Grazing or Feeding Operations)

N. Benson Cr. into Benson Cr.

Franklin 0.8 to 2.0

WAH (partial)


Agriculture

Organic Enrichment (Sewage) Biological Indi-cators

Agriculture

Sedimentation/ Siltation Agriculture; Highway/Road/Bridge Run-off (Non-construction related); Highways, Roads, Bridges, Infrastructure (New Con-struction)

N. Fk. N. Ben-son Cr. into N. Benson Cr.

Franklin 0.0 to 2.2

WAH (partial)


Agriculture; Loss of Riparian Habitat; Post-development Erosion and Sedimen-tation

Sedimentation/ Siltation Agriculture; Loss of Riparian Habitat; Post-development Erosion and Sedimen-tation

Materials and Methods 5

Figure 2.1 Goose Creek watershed and 303(d)-listed stream reaches (river miles 0.0 to 1.8 and 1.85 to 4.2, as listed in Table 2.1).

Figure 2.2 Confluence of Benson Creek (top right) and the Kentucky River during a flood event.


Geology and Topography

Goose Creek and Benson Creek watersheds are located in the Eden Shale Belt (Newell 2001) sub-region of the Bluegrass physiographic region of Kentucky. Dissection by streams has occurred to a high degree, with little flat land present in this area that surrounds the In-ner Bluegrass sub-region. The Eden Shale Belt is characterized by narrow, v-shaped valleys and narrow ridges of moderate relief with thin soil and poorly exposed bedrock.

The underlying rock is predominantly Clays Ferry formation (Ocf), with minor amounts of Tanglewood limestone (Olt) (a member of Lexington Limestone Formation) and Callo-way Creek limestone (Occ) (Figure 2.3). The Clays Ferry Formation, which is 90 to 300 ft thick, comprises interbedded shale, limestone, and minor siltstone (Figure 2.4). The shale, which comprises about 50 percent of the formation, is medium to olive gray, weathers yel-lowish gray. The uppermost 15 to 20 ft of the Clays Ferry Formation contains as little as 25 percent shale, some thin intervals contain as much as 75 percent. The limestone, which comprises about 45 percent of the formation, is of several types (Cressman 1973): (1) medium gray, containing abundant brachiopods and bryozoans in micrograined calcite matrix, in beds mostly 0.2 to 0.5 ft thick; (2) similar to above but containing some sparry calcite cement; (3) medium gray, crinoidal, in beds as much as 1.5 ft thick, most common in lower half of formation; and (4) medium to dark gray, micrograined, argillaceous (contain-ing a minor but significant amount of clay minerals), in beds mostly 0.1 to 1.5 ft thick. The siltstone, which makes up about 5 percent of the uppermost 40 ft, is yellowish brown, cal-cereous, and occurs in beds mostly 0.1 to 0.3 ft thick.

Tanglewood limestone, a member of Lexington Limestone Formation, is phosphatic, medium-gray to light-brownish-gray fossil-fragmental (Figure 2.5), and occurs in even to

Figure 2. 3 Geological map of Goose Creek watershed showing Calloway Creek Limestone (purple, left), Clays Ferry Formation (pink, center), and Tanglewood Lime-stone Member (brown, top right). Note unnamed tribu-tary underlain by Lexington Limestone, which is intensely karst-prone (labeled “A”).

A


Figure 2.4 Rock cut showing Clays Ferry Formation and friable shale.

Figure 2.5 Rock cut showing Tanglewood Limestone Member.

irregular beds 0.05 to 0.2 ft thick, in crossbedded sets mostly 0.2 to 0.4 ft thick. It has in-tense karst-prone lithology, and numerous sinkholes and springs are mapped in the Blue-grass region (KGS 2006), although none are shown in Goose Creek watershed. The Tangle-wood limestone is only exposed in a small area, but significant subsurface flow has occurred in this unit, particularly at an unnamed tributary of Goose Creek (see Figure 2.3).

The Calloway Creek limestone includes limestone (80 percent) and shale (about 20 percent). The limestone is mostly medium light gray to olive gray, weathers medium light gray, and is poorly sorted. The limestone is fine- to coarse-grained, fossil fragmental, and occurs in irregular beds mostly 0.05 to 0.2 ft thick. The shale is medium light gray to light olive gray, and occurs in irregular partings mostly less than 0.05 ft thick. The Occ for-mation is characterized by abundant large bryozoans; brachiopods, pelecypods, and trilobite and crinoid fragments also present. On uplands the bedrock commonly overlain by soil 5 ft thick; in places, it may be as much as 10 ft thick. Small sinkholes are common near the base of the formation. The Clays Ferry is not listed as a karst prone lithology, and no sink holes or springs are mapped in this unit in Goose Creek (KGS 2009). The Callaway Creek lime-stone formation is moderately karst-prone but outcrops only on the ridges in Goose Creek, so karst landforms are not common or extensive in this unit.

Soils

Soil depths are shallow to moderate on steep slopes and variable on ridgetops (Sims et al. 1968). Soils may be moderately deep on floodplains and terraces of the Goose Creek main stem (USDA 1980; Parola et al. 2007). The majority of the Goose Creek watershed is covered by Eden silty clay soils (Figure 2.6), which are classified as severely eroded (Ta-ble 2.2). The Eden silty clay loam (EcC) occurs in long winding areas on narrow ridges (USDA 1980). Permeability is slow and runoff is rapid. The parent material is a clayey re-siduum weathered from shale and siltstone and/ or limestone (USDA 1980). The EcC soils are moderately deep, well drained and used for pasture, hay and cultivated crops. It is diffi-cult to till because the surface layer typically includes subsoil material. The erosion hazard for this soil is severe; under cultivation measures for controlling erosion are required. The Eden flaggy silty clay (EdE3) occurs in long, narrow bands to broad areas dissected by small drainageways every 300 to 1000 ft (USDA 1980). Permeability is slow and runoff is rapid.


Figure 2.6 Distribution of soil types within Goose Creek watershed (Source: USDA-SSURGO).

Table 2.2 Goose Creek Watershed Soils Map Unit Area Symbol Map Unit Name (acres) (%) Bo Boonesboro silt loam 8.6 0.2 DAM Dam, large earthen 1.3 0.0 EcC Eden silty clay loam, 6 to 20 percent slopes 556.9 9.7 EdE3 Eden flaggy silty clay, 20 to 30 percent slopes,

severely eroded 3774.3 66.0

ElB Elk silt loam, 2 to 6 percent slopes 9.8 0.2 FaC Faywood silt loam, 6 to 12 percent slopes 15.9 0.3 FdD Faywood silty clay loam, 12 to 20 percent slopes 82.6 1.4 LoB Lowell silt loam, 2 to 6 percent slopes 118.3 2.1 LoC Lowell silt loam, 6 to 12 percent slopes 427.0 7.5 NhB Nicholson silt loam, 2 to 6 percent slopes 245.1 4.3 No Nolin silt loam 307.8 5.4 ShB Shelbyville silt loam, 2 to 6 percent slopes 146.7 2.6 W Water 15.6 0.3 Total 5709.9 100.0


Slopes are steep, (20-30 percent), most areas are severely eroded, and deep gullies are not uncommon. The parent material is clayey residuum weathered from shale and siltstone and/or limestone (USDA 1980). The EdE3 soils are moderately deep, well drained and used for woods or brush. Steep slopes, severe erosion hazard, and flagstones make this soil poorly suited to cultivation and an important soil type for sediment production.

Silt loams constitute most of the other soils in the watershed. Lowell silt loam (LoC) is on sloping, convex ridgetops and concave side slopes. LoC occurs in long narrow areas amd is typically dissected by many small drainageways (USDA 1980). Permeability is moderate-ly slow and runoff is rapid. The parent material is clayey residuum weathered from lime-stone and shale (USDA 1980). LoC soils are deep, well drained and used for hay, pasture and cultivated crops. The erosion hazard for this soil is severe; under cultivation measures for controlling erosion are required. Nolin silt loam (No) is found in narrow to fairly wide valley bottoms. Permeability is moderate and runoff is medium. Slopes are uniform and typ-ically less than 2 percent. The parent material is mixed fine-silty alluvium (USDA 1980). The No soils are deep, well drained and used for row crops (primarily corn and soybeans), hay and pasture. This soil has a low erosion hazard, and it is considered suitable for tilling.

Land Cover

The land cover in the Goose Creek watershed is primarily deciduous forest along small-er streams and on hillsides, with hay and pasture on the broader floodplains and on flatter ridgetops (Table 2.3 and Figure 2.7). Since 1992, land use has changed only slightly. The biggest changes have been decreases in mixed forest and cultivated crops and increases in pasture/hay and developed open space.

Table 2.3 Goose Creek Watershed Land Use (USGS 2008a, b) NLCD 1992 Area 2001 Area

Land Cover Code (mi2) (%) (mi2) (%) Open Water 11 0.008 0.1 0.015 0.1 Developed, Open Space 21 0.095 0.1 0.564 5.5 Developed, Low Intensity 22 0.004 < 0.1 0.257 2.5 Developed, Medium Intensity 23 0.043 0.42 0.033 0.3 Developed, High Intensity 24 0.017 0.2 Barren Land 31 0.011 0.1 Deciduous Forest 41 4.757 46.1 4.936 47.8 Evergreen Forest 42 0.842 8.2 0.880 8.5 Mixed Forest 43 2.255 21.8 0.274 2.7 Scrub/Shrub 52 0.261 2.5 Grassland/Herbaceous 71 0.315 3.1 Pasture/Hay 81 1.609 15.6 2.733 26.5 Cultivated Crops 82 0.649 6.3 0.026 0.3 Urban recreational grasses 85 0.066 0.6 N/A Woody Wetlands 90 0.001 < 0.1 Emergent Herbaceous Wetlands 95 0.003 < 0.1 Total 10.328 99.32 10.326 100.3


Figure 2.7 Land cover in Goose Creek watershed (2001 NLCD data).

Climate

Kentucky has a moist-continental climate with distinct seasonal differences and variable weather patterns. Winter temperatures are moderate, rarely below 0°F; typical summer tem-peratures are warm and rarely above 100°F. Average annual snowfall is about 20 in., but the snow cover rarely remains longer than three days at a time.

Weather patterns in Kentucky are affected variably by the meeting of cold, continental air masses arriving from the northwest and warm, moist air masses moving up the Missis-sippi and Ohio River Valleys from the southwest (Conner 1982). The rainfall pattern in Franklin County is bimodal (Figure 2.8) with the most rainfall in May (4.61 in) and a sec-ondary peak (3.71 in) in December (1971-2000 data) (MRCC 2009). The lowest rainfall is in October (2.66 in) (1971-2000 MRCC 2009). Although September is usually a relatively dry month, the second wettest one-day maximum rainfall occurred in September 1897 (Ta-ble 2.4).

Temperature is unimodal, with the hottest temperatures in July (monthly average high of 86.9°F, monthly average low of 63.4°F, 1971-2000 data) (MRCC 2009). The coldest temperatures are in January with average monthly high of 39.8°F and a monthly average low of 20.8°F (1971-2000 data) (MRCC 2009). The growing season is between 157 days (based on 32°F threshold) and 184 days (28°F) (Table 2.5). The longest growing season on record was 212 days (32°F) and 239 days (28°F).


Figure 2.8 Monthly temperature and precipitation for 1971-2000 at Frankfort Lock and Dam 4 (Source: NOAA).

Table 2.4 Precipitation Extremes Period of Record: 1896-2001

Month High (in) Year

Low (in) Year

1-Day Max (in) Date

Jan 20.05 1937 0.41 1981 3.20 01-21-1937 Feb 11.82 1909 0.32 1963 5.93 02-16-1990 Mar 14.30 1997 0.21 1910 4.68 03-19-1943 Apr 9.29 1970 0.67 1976 3.20 04-25-1975 May 12.99 1983 0.81 1936 4.32 05-08-1961 Jun 11.16 1973 0.02 1936 4.00 06-16-1949 Jul 11.37 1955 0.42 1997 3.70 07-31-1927 Aug 8.55 1974 0.08 1943 4.41 08-08-1995 Sep 11.17 1979 0.39 1897 5.78 09-14-1979 Oct 8.35 1919 0.21 1934 3.01 10-20-1993 Nov 10.36 1900 0.39 1904 4.75 11-20-1900 Dec 10.20 1990 0.48 1925 2.97 12-04-1922

Table 2.5 Length of Growing Season* Base Temp Days

°F Median Shortest 10% 90% Longest 32 157 135 140 202 212 30 170 150 154 205 227 28 184 158 164 218 239 24 212 174 187 243 257 20 228 197 199 263 283 16 261 207 217 284 288

* Derived from 1971-2000 averages.

0

2

4

6

8

10

12

14

16

18

20

0

10

20

30

40

50

60

70

80

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JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Prec

ipita

tion

(inch

es)

Tem

pera

ture

(°F)

Precip (in)Avg High (°F)Mean (°F)Avg Low (°F)


Precipitation in winter months generally results from frontal storm systems. Precipita-tion in summer is characterized by convective storm activity, typically in the form of after-noon thunderstorms. The intensity of precipitation is generally higher in summer than during other seasons, but the number of days having precipitation is similar in winter and summer.

2.2 STUDY DESIGN

Each of the sedimentation processes related to the delivery of sediment from source to watershed mouth (Table 2.6) were assessed using combinations of four types of methods: indices, direct measurements, erosion models, and extrapolation of estimates from rating curves or other data (USEPA 1999). A geomorphic source assessment was conducted to identify the types and locations of sources of sediments and to quantify their respective con-tributions to Goose Creek watershed sediment loads. The assessment also was designed to help statistically link existing sediment loads with sediment sources and mechanisms influ-encing sediment impairment of water quality and substrate habitat. Data collection methods were selected to identify areas with high loads during flood flows, based on the hypothesis that those areas would be most affected by siltation during major and/or very frequent flood events that transport the highest annual loads of fine-grained sediment, and embeddedness would be correspondingly higher at the locations of the highest annual loads.

Table 2.6 Summary of Source Assessment Methods

Sedimentation Process Indices Direct

Measure Erosion Models

Extrap-olation

Production Channel erosion (weathering and mobilization of channel bank sediments) X X X X Upland erosion and delivery (supply of eroded sediment to the channel) X X

Storage In-channel storage (deposition of sediments in the channel) X Floodplain storage (deposition of sediments near the channel) X X

Transport In-channel transport: suspended sediment load (movement of sediment

downstream within the watershed) X X

In-channel transport: suspended sediment yield (export of sediment from the watershed)

X X

The identified links between sources of high loads and impairments would be used to

determine the capacity of the watershed to assimilate its sediment load (i.e., the sediment supply that can be transported and stored without embedding riffles) while supporting its designated uses. The load reduction necessary to support WAH designated use would be es-timated from the difference between that assimilative capacity of the watershed and the ex-isting load. The estimated load reduction then would be allocated to sources based on their relative magnitude and influence on the impairment—areas of high sediment production would be identified as priority areas or reaches for BMP implementation—and the potential feasibility and effectiveness of BMP implementations.

The source assessment was completed in three phases:


1. Remote Watershed Assessment: Existing documentation of the watershed was analyzed to delineate Goose Creek and Benson Creek watersheds and identify characteristics that could be relevant to field evaluation of Goose Creek water-shed and analysis of monitoring data.

2. Field Assessment: Field observations of the Goose Creek main stem, tributary channels, and their valleys were used to identify to identify sources of sediment production, floodplain storage areas, and potential reference reaches. Reach- and sub-reach-scale observations and measurements were used to assess indicators of channel and floodplain stability and habitat quality. The indicator assessment helped in determining where impairments occurred, which erosion and deposi-tion processes or conditions influenced the impairments, and how source loca-tions were related to impairment locations.

3. Detailed Monitoring and Field Measurements: Locations identified as sediment sources or storage areas were evaluated for selection as Phase 3 assessment sites. Sediment deposits in small farm ponds were measured, and at selected sites, stream bank erosion, floodplain storage, suspended sediment concentration (SSC), and discharge were monitored for 12-14 months in 2007 and 2008 to quantify sediment production, storage, and transport in Goose Creek watershed.

2.3 REMOTE WATERSHED ASSESSMENT

Extensive development of watershed geomorphic assessment protocols have been de-veloped by the Vermont Agency of Natural Resources (VTANR 2004). While some of the protocols are now incompatible with current versions of ArcGIS, they were applied as close-ly as possible in the remote assessment. The following data collection and ArcGIS analysis were completed in this remote sensing phase:

1. The National Hydrologic Dataset’s HUC 14 boundaries were used to delineate the Benson Creek watershed and its subwatersheds and to estimate their surface drainage areas.

2. The Goose Creek watershed was located on the 1960s USGS 7.5-minute map of the Waddy, Kentucky, quadrangle, and reaches were delineated for assessment:

a. The watershed boundaries of Goose Creek and its tributaries were delineated, and their surface drainage areas were estimated.

b. The entire extents of all Goose Creek watershed channel reaches delineated by dashed or solid blue-lines on the USGS quadrangle map were selected for field assessment.

3. Goose Creek watershed channel and valley geomorphic characteristics were recorded from the USGS quadrangle map: elevations of downstream and up-stream limits of the blue-line channels; valley lengths; valley slopes; hillside slopes; channel lengths; channel slopes; sinuosities; drainage areas; and valley widths. Valley constrictions or sharp bends that could create backwater during high flows were identified, and channel modifications were recorded:

a. Blue-line stream reaches in Goose Creek watershed were examined for evidence of channel straightening, realignment, or other modifications such as excavation for old mill races.

b. Any structures spanning or encroaching on the stream channels were identified.


c. The 1960s course of the streams on the topographic map was compared with the present alignment documented by aerial photographs, and discrepancies were recorded.

4. Geology, soil, land use, and hydrology characteristics of Goose Creek watershed were identified:

a. The bedrock strata underlying the watershed were identified from KGS 7.5-minute geologic quadrangle maps.

b. NRCS soil surveys were examined to identify the soil types. c. Land use was identified from the US Geological Survey’s 2001 national land

cover database (USGS 2008). d. Aerial photographs were examined to estimate riparian buffer widths and

identify recent land use changes and possible impacts to channels and valleys. e. Maps indicating karst-prone areas (KGS 2006) at scales of 1:500,000 and

Kentucky Geological Survey (KGS) 7.5-minute geologic quadrangle maps (1:24,000) were checked for karst-prone strata.

5. The Bluegrass regional geomorphic assessment completed for KDOW (Parola et al. 2007) was reviewed for information about stream geomorphic characteris-tics and the effects of geology, historical land use, and current land use on sedi-ment loads and channel evolution.

2.4 FIELD ASSESSMENT

Field observations of the Goose Creek main stem, tributary channels, and their valleys were used to identify to identify sources of sediment production, floodplain storage areas, and potential reference reaches. Reach- and sub-reach-scale observations and measurements were used to assess indicators of channel and floodplain stability and habitat quality. The in-dicator assessment helped in determining where impairments occurred, which erosion and deposition processes or conditions influenced the impairments, and how source locations were related to impairment locations. Indicators selected for assessment were the ten param-eters from the EPA Rapid Bioassessment Protocol (RBP) for high-gradient streams (Barbour et al. 1999). These indexed parameters were used not to quantitatively evaluate habitat quali-ty but rather to organize observations and allow standardized comparisons of reaches throughout the watershed. The RBP parameters include embeddedness, which was used as an indicator of siltation. Siltation refers to the deposition of fine sediment, primarily silt, over a coarser substrate, while embeddedness is defined as the degree to which fine sedi-ments surround coarse substrates on the surface of a streambed (Sylte and Fischenich 2002). As an RBP parameter, embeddedness is evaluated as “the extent to which rocks (gravel, cobble, and boulders) and snags are covered or sunken into the silt, sand, or mud of the stream bottom … in the upstream and central portions of riffles and cobble substrate areas” (Barbour et al. 1999, p. 5-13). Although error associated with assessment of embeddedness tends to be high (MacDonald et al. 1991), that was not a relevant factor in its selection as an indicator for this project because it was used only to record locations of impaired substrate habitat and the relative degree of embeddedness compared to other reaches.

The RBP bank stability and bank vegetative protection parameters were assessed using the Bank Assessment for Non-point Source Consequences of Sediment (BANCS) method (Rosgen 2001). The BANCS method uses three bank erodibility estimation tools to predict streambank erosion rates: bank erosion hazard index (BEHI); near bank stress (NBS); and


direct measurements of bank erosion. BEHI risk ratings are based on measurements, ratios, and ranges of several stream bank variables, while NBS risk ratings are based on indicators of the potential for stress from flows in the near-bank region. These risk ratings were com-bined with data from direct measurements of bank erosion to develop a relation for predict-ing annual erosion rates for stream reaches throughout the watershed.

All RBP, BEHI, and NBS data were plotted individually on topographic maps to identi-fy possible links between types, locations, and distributions of sources, unique channel or valley characteristics, and embeddedness. This spatial analysis was also used to identify wa-tershed-scale trends or areas to be targeted for BMP implementation.

Site Selection

The selection of blue-line and unmapped reaches for field assessment was finalized dur-ing an initial field evaluation. Several blue-line tributaries were excluded due to difficulty in access (GCT1) or the construction of a large pond on private land (BBT4) (Table 2.7 and Figure 2.9). More than 10,000 ft of unmapped sections of other tributaries were selected as assessment reaches where access was possible.

Table 2.7 Assessed Blue-Line* Stream Reaches Reach

ID Length

(ft) DA

(downstream) DA

(upstream) Assessed Reach Description GC1 2376 10.32 10.14 Yes Goose Cr main stem GC2 3361 8.09 7.89 Yes Goose Cr main stem GC3 4323 6.19 5.95 Yes Goose Cr main stem GC4 5134 2.19 1.65 Yes Goose Cr main stem GC5 2915 0.92 0.68 Yes Goose Cr main stem GC6 4379 0.5 0.11 Yes Goose Cr main stem BB1 1459 3.74 3.56 Yes Ballard Br main stem BB2 3226 2.67 2.44 Yes Ballard Br main stem BB3 2847 1.59 1.18 Yes Ballard Br main stem BB4 1525 0.92 0.83 Yes Ballard Br main stem BB5 4471 0.56 0.12 Yes Ballard Br main stem WB1 3958 1.2 0.88 Yes Watts Br main stem WB2 6181 0.74 0.1 No Watts Br main stem GCT1 6858 0.57 0.1 Yes Unnamed Trib 1 of Goose Cr GCT2A 4607 1.47 1.03 Yes Unnamed Trib 2 of Goose Cr GCT2B 1940 0.77 0.67 Yes Unnamed Trib 2 of Goose Cr GCT2C 1014 0.33 0.27 Yes Unnamed Trib 2 of Goose Cr GCT2D 2974 0.18 0.11 Yes Unnamed Trib 2 of Goose Cr GCT3 5934 0.49 0.12 Yes Unnamed Trib 3 of Goose Cr GCT4 4379 0.72 0.19 Yes Unnamed Trib 4 of Goose Cr BBT1 3280 0.15 0.1 No Unnamed Trib 1 of Ballard Br BBT2 9571 0.89 0.1 No Unnamed Trib 2 of Ballard Br BBT3 8250 0.84 0.1 Yes Unnamed Trib 3 of Ballard Br BBT4 3310 0.3 0.12 No (pond) Unnamed Trib 4 of Ballard Br BBT5 3236 0.25 0.11 No Unnamed Trib 5 of Ballard Br BBT6 2138 0.26 0.1 Yes Unnamed Trib 6 of Ballard Br WBT1 2548 0.14 0.1 No Unnamed Trib 1 of Watts Br * This list does not include the unmapped channels that were also assessed.


Figure 2.9 Assessed blue-line reaches in the Goose Creek watershed.

Data Collection

The RBP and BANCS assessment observations and measurements were made in the winter of 2006/2007, when leaf-off permitted greater visibility of stream banks and hillslopes, and all intermittent reaches had continuous flow over riffles. Hydrologic condi-tion was documented in late summer in 2008.

Photo-documentation The channel and the floodplain of each blue-line and unmapped assessment reach were

photo-documented using a high-resolution digital SLR camera and a handheld Geographical Positioning System (GPS) receiver pre-loaded with USGS 1:24,000 topographic maps. A confluence or bridge was selected as a reference point that marked the downstream limit of each reach. The geo-referenced photo-documentation was initiated at the reference point and continued up to the drainage divide, the end of the blue-line stream or the next reach. At regular intervals (not more than 10 channel widths), a GPS reading and photograph were taken. The identifier numbers of each photograph and its corresponding GPS data point were synchronized so each photograph could be tied to a specific geographic location. To maxim-ize the accuracy of GPS measurements, multiple readings (typically 30-60) were averaged to produce each GPS data point.


In-Stream and Riparian Habitat Assessment RBP parameters were evaluated throughout each blue-line and unmapped assessment

reach. Sub-reach-scale parameters (Table 2.8) were evaluated at intervals of approximately 100 ft during the field assessment. Reach-scale parameters (Table 2.9) were rated using a combination of field assessment, GPS measurements, topographic maps, and aerial

Table 2.8 RBP Sub-Reach-Scale Parameters

Parameter Rationale Scoring Method

Scoring Range

(Optimal to Poor)

Assessment Method

1 Epifaunal substrate/ available cover

Includes the relative quantity and variety of natural structures in the stream, such as cobble (riffles), large rocks, fallen trees, logs and branches, and undercut banks, available as refugia, feeding, or sites for spawning and nursery functions of aquatic macrofauna.

% substrate favorable for epifaunal colonization and fish cover

>70% 40-70% 20-40% <20%

GIS analysis of field photo-documentation

2 Embeddedness Refers to the extent to which rocks (gravel, cobble, and boulders) and snags are covered or sunken into the silt, sand, or mud of the stream bottom in the upstream and central portions of riffles and cobble substrate areas.

% gravel, cobble and boulders surrounded by fine sediment

0-25% 25-50% 50-75% 75-100%


3 Velocity/depth combinations

Patterns of velocity and depth are an important feature of habitat diversity. The best streams in most high-gradient regions will have all 4 patterns present: (1) slow-deep, (2) slow-shallow, (3) fast-deep, and (4) fast-shallow. The general guidelines are 0.5 m depth to separate shallow from deep, and 0.3 m/sec to separate fast from slow.

Presence of slow-deep, slow-shallow, fast-deep, fast shallow

4 regimes 3 2 1


4 Sediment deposition

Measures the amount of sediment that has accumulated in pools and the changes that have occurred to the stream bottom as a result of deposition. Sediment deposition may cause the formation of islands, point bars (areas of increased deposition usually at the beginning of a meander that increase in size as the channel is diverted toward the outer bank) or shoals, or result in the filling of runs and pools.

Enlargement of islands or point bars and % bottom affected by sediment deposition

<5% 5-30% 30-50% >50%


5 Channel flow status

The degree to which the channel is filled with water. The flow status will change as the channel enlarges (e.g., aggrading stream beds with actively widening channels) or as flow decreases as a result of dams and other obstructions, diversions for irrigation, or drought.

% substrate exposed between base of lower banks

100% 75-100% 25-75% Very little

water – standing pools



Table 2.9 RBP Reach-Scale Parameters

Parameter Rationale Scoring Method

Scoring Range

(Optimal to Poor)

Assessment Method

6 Channel alteration

Is a measure of large-scale changes in the shape of the stream channel. Channel alteration is present when artificial embankments, riprap, and other forms of artificial bank stabilization or structures are present; when the stream is very straight for significant distances; when dams and bridges are present; and when other such changes have occurred.

Degree of channelization or dredging. Channel pattern

None no recent

(20 yrs) 40-80%

disrupted over 80%

channelized

GIS analysis of field photo-documentation.

7 Frequency of riffles

Is a way to measure the sequence of riffles and thus the heterogeneity occurring in a stream. Riffles are a source of high-quality habitat and diverse fauna, therefore, an increased frequency of occurrence greatly enhances the diversity of the stream community.

Ratio of distance between riffles (or boulder obstructions in steeper streams) to width of stream

7:1 7-15:1 15-25:1 >25:1

GPS readings taken at crest of each riffle: distances estimated in GIS

8 Bank stability

Measures whether the stream banks are eroded (or have the potential for erosion). Steep banks are more likely to collapse and suffer from erosion than are gently sloping banks, and are therefore considered to be unstable. Signs of erosion include crumbling, unvegetated banks, exposed tree roots, and exposed soil. Eroded banks may indicate a problem of sediment production, and suggest a scarcity of cover and organic input to streams.

Evidence of erosion or bank failure

<5% 5-30% 30-60% 60-100%

BEHI

9 Bank vegetative protection

Measures the amount of vegetative protection afforded to the stream bank and the near-stream portion of the riparian zone. The root systems of plants growing on stream banks help hold soil in place, thereby reducing the amount of erosion that is likely to occur.

% streambank and riparian zone covered by native vegetation

100-90% 70-90% 50-70% <50%

BEHI

10 Riparian vegetative zone width

Measures the width of natural vegetation from the edge of the stream bank out through the riparian zone. The vegetative zone serves as a buffer to pollutants entering a stream from runoff, controls erosion, and provides habitat and nutrient input into the stream. A relatively undisturbed riparian zone supports a robust stream system.

Riparian zone width and degree of human impacts

>18 m (no human)

12-18 m (minimal human)

6-12 m (great deal human)

<6 m

Average of 12 equally-spaced measurements from aerial photos

photography. Channel alteration was identified in the field; topographic maps then were re-viewed to confirm the identified alterations. Common features used as evidence of alteration included levees, tracks for bulldozers or other heavy machinery, scraped channel bars, cleared vegetation, straightened channel reaches, or channel crossings. The locations of rif-fle crests were recorded in the field using a handheld GPS. The bank stability and bank veg-


etative protection parameters were measured as part of the BANCS assessment of BEHI and NBS (Rosgen 2006).

BEHI Parameter Assessments The locations and erodibility characteristics of eroding banks were inventoried along

the entire length of each blue-line and unmapped channel geomorphic assessment reach, and locations identified as suitable for bank erosion monitoring were flagged for potential selec-tion as Phase 3 monitoring sites. At each eroding bank, the location of the upstream and downstream extent of the bank was measured using a handheld GPS. GPS readings were av-eraged for at least 60 seconds to ensure a reliable position. The following parameters were measured and photographed in order to calculate BEHI indices (Table 2.10):

1. Bank height was measured with a ruler from the bank toe to the top of the erod-ing bank face. The bank toe was delineated as the transition from bed to bank sediments. This transition was often at the intersection of bedrock on the bed and fine-grained alluvial deposits that compose the banks. In some places, the transi-tion was between bedrock and fine gravel. The top of the eroding bank face was determined by the presence or absence of perennial covering vegetation.

2. Bankfull depth was estimated from bankfull benches within each reach; often a bankfull bench was not present adjacent to the eroding bank, but the bankfull depth was assumed to be representative of the reach as a whole.

3. Bank angle was measured simply by measuring the height of the bank and the horizontal distance from the bank toe to the top of bank using a pocket rod. Where the shape of the bank was more complicated (such as an overhanging bank), the height and horizontal run of the steepest face was measured.

4. Root depth was measured from the top of the bank to depth at which significant amount of root material was found. In practice defining a line where most of the roots stopped was simple, as the bedrock or weathered bedrock fragments often marked the rooting depth. Occasionally, a few roots penetrated deeper than the majority; in these situations the rooting depth included the outlier if it was a large tree root. Small thin roots below the average rooting depth were not included.

5. Root density was estimated as the percentage of the soil that was composed of roots in the zone where roots were present.

6. Bank protection was measured by visually determining how much of the bank was not exposed to surface erosion processes. Sod mats, large woody debris, and rip-rap are common types of surface protection.

7. Bank material type and stratigraphy was visually assessed at each bank. The BEHI method distinguishes between bedrock, boulders, cobble, gravel, and sand, all of which were easily identified in the field without subsequent laboratory tests. Bedrock was present only at the bank toe and the channel bed at nearly all assessed banks. Scoring adjustments may be made for bank materials (e.g., add-ing 10 points for sand) and for stratification (e.g., adding 5-10 points for an un-stable layer), but no adjustments are recommended for silt/clay bank materials, which were by far the most common material in all of the assessed reaches. Thus, adjustments typically were not necessary in the Goose Creek assessment.


Table 2.10 BEHI Risk Ratings and Parameters (Rosgen 2001) Adjective Hazard or

Risk Rating Categories Bank Height /

Bankfull Height Root Depth / Bank Height

Root Density (%)

Bank Angle (Degrees)

Surface Protection (%) Totals

VERY LOW Value 1.0-1.1 1.0-0.9 100-80 0-20 100-80 Index 1.0-1.9 1.0-1.9 1.0-1.9 1.0-1.9 1.0-1.9 5-9.5

LOW Value 1.11-1.19 0.89-0.5 79-55 21-60 79-55 Index 2.0-3.9 2.0-3.9 2.0-3.9 2.0-3.9 2.0-3.9 10-19.5

MODERATE Value 1.2-1.5 0.49-0.3 54-30 61-80 54-30 Index 4.0-5.9 4.0-5.9 4.0-5.9 4.0-5.9 4.0-5.9 20-29.5

HIGH Value 1.6-2.0 0.29-0.15 29-15 81-90 29-15 Index 6.0-7.9 6.0-7.9 6.0-7.9 6.0-7.9 6.0-7.9 30-39.5

VERY HIGH Value 2.1-2.8 0.14-0.05 14-5.0 91-119 14-10 Index 8.0-9.0 8.0-9.0 8.0-9.0 8.0-9.0 8.0-9.0 40-45

EXTREME Value >2.8 <0.05 <5 >119 <10 Index 10 10 10 10 10 46-50

NBS Assessments NBS was visually assessed at the same time as the BEHI parameter measurements were

made. Because two identical stream banks may erode differently depending on the energy distribution against the stream bank, Rosgen (2006) uses the near bank stress (NBS) to index the energy distribution, which can be estimated in various ways. No guidance is given by Rosgen (2006) as to how estimates of NBS ratings from different methods are to be com-pared. In this project, the visual planform method (Rosgen 2006, p. 5-67) was used but was modified to include entrenchment and stream gradient, both of which influence NBS (Ta-ble 2.11). The visual method is the most rapid method provided by Rosgen. It requires no quantitative measurements but nevertheless can be an “accurate, appropriate method” (Rosgen 2006, p. 5-67). This method was less time consuming and involved less risk to per-sonnel than the more precise method of collecting velocity measurements for different flows, drawing velocity profiles in the near bank zone, and then estimating shear stresses from the velocity gradients.

The modified visual assessment proved to be easy to apply, and replicate assessments of the same site by trained personnel resulted in identical categorization. The scheme applied to the banks in Goose Creek watershed was developed after walking many miles of stream channels and thus was calibrated to local planforms, entrenchment ratios, and gradients. To develop a similar scheme for a different watershed might require different weightings of each parameter. For example, in low-gradient sandbed streams, the slope may be very diffi-cult to visually estimate, and woody debris jams may be a more significant control on NBS.

Table 2.11 NBS Risk Ratings and Parameters Risk Rating Planform Entrenchment Gradient

Low or very low Straight or inside of bend No entrenchment Below reach average (pool, backchannel) Moderate or high Outside of bend Moderate entrenchment Reach average (glide, run) Very high or extreme Converging, chute flow Highly entrenched Above reach average (riffle or rapid)


Hydrologic Condition Assessment In addition to the flow status recorded in the RBP, a separate assessment of hydrologi-

cal condition was recorded in late summer to map the presence or absence of flow. The hy-drologic condition is a measure of the duration and frequency of surface water and flow and is a fundamental parameter controlling the structure and function of aquatic communities (Boulton 2003; Fritz et al. 2006). At any given channel location, the hydrologic condition is a combination of groundwater/ base flow and/or storm- or quickflow. Groundwater/ base flow is the longer-term, sustained discharge derived from natural storage zones, while storm- or quickflow refers to the direct response to a rainfall event, which includes overland flow (runoff), lateral movement in the soil profile (interflow), and direct rainfall onto the stream (direct precipitation). The distinction between groundwater/ base flow and storm- or quickflow can be used to identify locations of transition between ephemeral, intermittent, and perennial flow regimes. Ephemeral channel reaches by definition respond to storm- or quickflow only, while intermittent channel reaches typically receive some delayed or base flow, especially during the wet season, and perennial stream reaches have base flow all year, except in extreme drought years. The upstream limit of base flow emergence during the wet season can also be considered the start of an intermittent reach and hence the location of the ephemeral-intermittent transition. Likewise, the downstream limit of base flow emergence during the dry season can be considered the start of a perennial reach and hence the location of the intermittent-perennial transition.

In order to identify the minimum extent of the drainage network, hydrologic condition was assessed on 24 September 2008 following a period of 1 week with no rain and 2 weeks with only trace precipitation recorded at Bluegrass Airport, approximately 25 miles east of Goose Creek (NOAA 2009). In total, less than 1.5 in of rainfall was recorded in September 2008, well below the monthly average. The hydrologic condition was identified by visually assessing the surface water and flow according to four categories:

Dry Isolated pools with water but no flow Regular pools with water but no flow Continuous flow through or over riffles

Locations where the hydrologic condition changed were recorded using a handheld GPS de-vice. Morphological features influencing the infiltration and exfiltration of groundwater (e.g., change in bed material from planar bedrock to alluvium) were documented in a field notebook and photographed. Tributaries upstream of a completely dry reach were assumed to be dry, and many were corroborated with a windshield survey of the headwater reaches.

Because drying of the bed was found to be prevalent throughout Goose Creek water-shed, the assessment was extended into other sub-watersheds of Benson Creek and into the Benson Creek main stem down to its confluence with South Benson Creek. South Benson Creek was excluded, however, because its geology is very different from the other subwater-sheds, and the stream would therefore be expected to have a different hydrologic response to recent rainfall. Extending the number of sites increased the range of drainage areas to in-clude streams draining up to 72.34 mi2.


Analysis of Watershed Geomorphic Characteristics

In-Stream and Riparian Habitat The ratings for the RBP point measurements, the longitude and latitude, and the corre-

sponding GPS/photograph number were entered into a GIS and plotted over topographic maps with a color assigned to each rating. Measurements of reach-scale parameters were made in GIS and were extracted to an Excel spreadsheet, where summary statistical parame-ters (mean, median, etc.) were calculated.

The sediment supply that can be stored on riffles without embedding them by more than 50 percent was estimated based primarily on visual observations and photo-documentation of median riffle widths and lengths by Strahler (1957) stream order, depth of intrusion, and void ratio (the percentage of a riffle that could be occupied by fine sediment). Bulk density (sediment mass per unit volume) was estimated based on bar samples collected in Curry’s Fork watershed and watersheds in Maryland (Croasdaile and Parola, unpublished data). The mass of sediment required to embed a single riffle by 50 percent was estimated as

Mass = width x length x intrusion depth x void ratio x bulk density

Riffle widths were estimated to be 10 ft for first- and second-order reaches; 15 ft for third- and fourth-order, and 20 ft for fifth- and sixth-order. Riffle lengths were variable throughout the watershed; an estimated median length of 15 ft was used in the calculations. The depth of intrusion for fine sediment was estimated as 0.3 ft. A void ratio of 0.3 was es-timated to represent a variable value in the watershed from about 0.2 to 0.5 (Carling and Reader 1982). The bulk density was estimated as 81 lbs/ft3 (1.3 g/cm3). The mass estimated for riffles in each stream order were then multiplied by the number of riffles observed in those stream orders for Goose Creek watershed and four subwatersheds: Ballard Branch, Goose Creek (mile 1.85 to 4.2), Watts Branch, and Goose Creek (mile 0.0 to 1.8) excluding Watts Branch. These products represent estimates of the estimated sediment mass that can be stored in the riffles of the subwatersheds at any given time without embedding them by more than 50 percent.

BEHI Parameters and NBS All BEHI and NBS measurements recorded in the field were entered into an Excel

spreadsheet. Using the method described by Rosgen (2006), the measurements were con-verted to scores for each parameter. The scores for each parameter were tallied to determine the BEHI and NBS risk ratings for each assessed reach.

The GPS coordinates of each measurement location, a reference for the photo-documentation, and the measured lengths of eroding banks were entered into the spread-sheet. The GPS points then were plotted over topographic maps and available aerial imagery in GIS. All RBP, BEHI, and NBS data were plotted individually on topographic maps to identify possible links between types, locations, and distributions of sources, unique channel or valley characteristics, and embeddedness. This spatial analysis was also used to identify watershed-scale trends or areas to be targeted for BMP implementation.

Hydrologic Condition All field designations of hydrologic condition were entered in to an Excel spreadsheet

with corresponding GPS locations and photo-documentation ID numbers. The point meas-


urements were imported into GIS, and the distance between points of the same hydrologic condition were interpolated along the blue-line stream course. The length of channel in each hydrologic condition category then was measured in GIS.

2.5 MONITORING SITE SELECTION

Locations identified in the geomorphic assessment as sediment sources or storage areas were evaluated for selection as sites for measurement of stream bank erosion, upland ero-sion, and floodplain storage. Mass erosion processes such as landslides and debris flows (Cenderelli and Kite 1998; Eaton et al. 2003) were not considered to be significant sediment sources in the Goose Creek watershed and were not assessed. Sediment from construction sites may be locally significant but was not assessed because guidelines for erosion preven-tion and sediment control already exist (e.g., Tonning 2007), and therefore, these potential sources were not targeted in this study as opportunities for load reduction.

Bank Erosion Monitoring Sites

The BEHI and NBS ratings were evaluated for each of the locations that were flagged during the field assessment as potential monitoring sites. Sites for installation of erosion pins in each blue-line and unmapped channel assessment reach were chosen according to the pro-tocol in Rosgen (2006): selected banks represented a range of BEHI and NBS combinations (e.g., very low BEHI/low NBS; high BEHI/moderate NBS; etc.) throughout the watershed. Based on this criterion, 48 locations were selected for monitoring of bank erosion (Fig-ure 2.10).

Figure 2.10 Locations of bank erosion monitoring sites.


Upland Surface Erosion Sites

Small farm ponds were selected as sites for measuring sediment production from upland surface erosion. Ponds were selected for assessment based on five criteria:

1. A known period of deposition (±10 percent). The period of deposition was typi-cally the time since construction or the time since the pond was dredged or cleaned out. The period of deposition had to be at least 10 years so that an easily measurable amount of sediment would have accumulated.

2. A clearly defined drainage area upslope of the pond. Ponds on top of a ridge were excluded.

3. Absence of a well-defined channel network upslope of the pond. 4. An outfall/spillway configuration that would lead to a high trapping efficiency

(Verstraeten and Poesen 2001). Ponds with extensive bank erosion above the in-let were excluded, as were and ponds with an outflow that was low enough to be frequently overtopped.

5. Accessibility. Ponds had to be accessible by vehicle.

Because no ponds within the Goose Creek watershed met these criteria, ponds in each of the other sub-watersheds of Benson Creek were evaluated. Nine ponds met the criteria and were selected for assessment (Table 2.12 and Figure 2.11).

Table 2.12 Assessed Ponds

Pond Name Deposition

Period (yrs) Drainage Area

(ha) Crawford 57 3.4 Gunn 25 3.8 Hickory Grove Rd 45 2.3 McDevitt 49 2.0 Perry 1 15 16.2 Perry 2 77 0.7 Sullivan 39 1.6 Wilson 1 27 3.8 Wilson 2 20 2.2

Floodplain Deposition Monitoring Sites

The two main criteria for selecting the locations for monitoring sediment deposition near blue-line assessment reaches were that the locations would not be disturbed either through mowing or grazing, and that they were well distributed throughout the watershed. Valley bottoms were evaluated according to these criteria during the bank assessment, and suitable locations with relatively flat areas away from major obstructions were flagged. A majority of reaches had suitable locations, and at most of those, three distinct depositional surfaces were selected for monitoring (Table 2.13): abandoned floodplains (terraces) of in-cised channel reaches; actively forming floodplains within incised channel reaches; and ac-tive floodplains of un-incised channel reaches. The active floodplain is the flat depositional surface adjacent to the channel that is constructed by the present river in the present climate and is frequently inundated by the river (Dunne and Leopold 1978). In incised channels, the


Figure 2.11 Locations of ponds surveyed in the Benson Creek watershed.

primary indicator used to identify the actively-forming floodplain was usually a low deposi-tional bench. In channels that were not incised, the active floodplain coincided with the val-ley flat.

Suspended Sediment Monitoring Sites

Three HUC14 subwatersheds and the largest tributary near the confluence of Goose and Benson creeks were selected for sampling (Table 2.14 and Figure 2.12). An extra site (GC2) was added to limit the increase in drainage area between sampler locations on Goose Creek. The sequence of samplers on the main stem of Goose Creek was also intended to identify segments where tributaries were contributing high or low loads. Sampling locations were se-lected based on the availability of a crossing structure or other immobile feature to which a sampler could be securely fastened near the mouth of the subwatershed.


Table 2.13 Locations of Sedimentation Mats Reach ID Latitude Longitude Bank Site Type GC1 38.15570 –85.01177 Left Terrace GC1 38.15570 –85.01186 Left Actively forming floodplain within incised channel GC2 38.15412 –85.01905 Right Active floodplain GC3 38.14925 –85.02942 Left Actively forming floodplain within incised channel GC3 38.14926 –85.02937 Right Active floodplain GC4 38.14036 –85.03905 Right Actively forming floodplain within incised channel GC4 38.14040 –85.03907 Left Terrace GC5 38.13381 –85.04209 Right Terrace GC5 38.13381 –85.04215 Left Actively forming floodplain within incised channel GCT2A 38.15787 –85.01616 Right Terrace GCT2A 38.15791 –85.01602 Left Actively forming floodplain within incised channel GCT3 38.15357 –85.02344 Right Actively forming floodplain within incised channel GCT4 38.13535 –85.04417 Right Actively forming floodplain within incised channel GCT4 38.13535 –85.04426 Left Terrace BB2 38.14907 –85.04702 Left Terrace BB2 38.14905 –85.04700 Right Actively forming floodplain within incised channel BB4 38.14787 –85.06053 Right Actively forming floodplain within incised channel BB4 38.14794 –85.06052 Left Terrace BBT1 38.15070 –85.03843 Left Actively forming floodplain within incised channel BBT1 38.15072 –85.03838 Right Active floodplain BBT3 38.15205 –85.04871 Right Active floodplain BBT3 38.15211 –85.04871 Left Terrace BBT6 38.14894 –85.06318 Right Terrace BBT6 38.14894 –85.06310 Left Terrace WB2 38.13313 –85.03033 Left Terrace WB2 38.13321 –85.03034 Right Terrace

Table 2.14 Suspended Sediment Monitoring Sites Reach

ID Sampling Site Name Sampler Location Description

Stream Order

Drainage Area (mi2) Latitude Longitude

GC1 Goose Crab Orchard Rd

On left bridge abutment of Crab Orchard Rd (CR-1230) bridge, just upstream of confluence with Benson Creek

4 10.27 38.15762 –85.00668

GC2 Goose Cave On right bank tree near cave and spring 4 8.07 38.15391 –85.01546 GC3 Goose I-64 On left bank, mounted to tree, just

upstream of I-64 bridge 4 5.97 38.14768 –85.03085

BB1 Ballard Branch

Right abutment of private bridge, just upstream of confluence with Goose Creek

3 3.58 38.1477 –85.03464

GCT2 Goose Trib Upstream of culvert on right bank 2 1.47 38.15570 –85.01393


Figure 2.12 Suspended sediment sampler locations in the Goose Creek watershed.

2.6 MONITORING DATA COLLECTION

Sediment deposits in selected pond sites were measured, and at selected stream and floodplain sites, stream bank erosion, floodplain storage, SSC, and discharge were moni-tored for 12-14 months in 2007 and 2008 to quantify sediment production, storage, and transport in Goose Creek watershed.

Bank Erosion Monitoring

Annual erosion rates were measured by installing erosion pins in eroding banks and monitoring them over a period of 12-14 months. A total of 136 erosion pin measurements were made at the 48 monitoring locations. Erosion pins were made from 2-to-3-ft steel rods, 0.25 in in diameter. The erosion pins were installed at the approximate elevation of the downstream riffle crest, at the bankfull level, and midway between the bankfull level and the top of the bank. In short banks (< 2 ft high), only two pins were installed: at the water sur-face and the bankfull level. The location of the bank pins was determined to give a range of representative conditions within a particular reach from slowly eroding banks to the banks experiencing severe erosion. The erosion pins were installed horizontally and carefully hammered into the bank until the end of the pin was flush with the bank surface.


The bank pins were installed from September to November 2007, and their GPS loca-tions were recorded. The GPS points and a handheld metal detector were used to find the pins on subsequent survey visits. Each of the pins was resurveyed in August 2008 and Janu-ary 2009.

The protrusion of the erosion pins was measured to the nearest 0.01 ft using a pocket rod, and then the pins were hammered into the bank until flush. A disadvantage of installing the pins flush with the bank is that negative readings are difficult to detect. However, a met-al detector was sensitive enough to detect most buried pins, and hence the depth of accumu-lated sediment could be estimated, albeit with less precision than exposed pins because of the disturbance to the bank profile caused by uncovering the pins.

Pond Cores

Area of deposition, volume of sediment deposition, and bulk density were measured at each pond during the summer of 2007. The pond perimeter and the volume of sediment de-posited above the water surface were surveyed using standard total station equipment and methods. The pond perimeter was defined as the top of deposited sediment. Deposited sedi-ment was visually distinct from the eroded soil in that it was generally layered, poorly con-solidated, and minimally vegetated. Depth measurements could not be obtained using the to-tal station due to the difficulty in keeping the boat and survey rod still enough to take a reading. Instead, a survey grid around the pond perimeter was established, and cross section measurements collected from the boat were referenced to that survey grid. The number of cross sections surveyed ranged from 4 to 11, depending on the size and shape of the pond. Along each cross section, two series of measurements were made: the depth to the top of de-posited sediment and the depth to the bottom of deposited sediment (marked by increased resistance due to bedrock or clay liner). At least seven pairs of measurements were recorded along each cross section.

To estimate bulk density, a series of sediment cores were collected in each pond using a modified Open Push Tube Sampler (ASCE 2000; McKean and Nordin 1986). At least five submerged cores were collected at each pond. All submerged sediment cores were extracted from the PVC on site using compressed air and were transferred to the laboratory for further analysis.

Sediment cores collected above the water surface could not be extracted without remov-ing surrounding sediment, so a modified collection procedure was used. Only one surface core per pond was collected because this sediment covered a much smaller area than the submerged sediment. A thin-walled PVC tube was inserted until stiff resistance was met. The core was then loosened by removing the surrounding sediment using a spade and by hand. Once the core was detached from the surrounding sediment, the core was twisted and removed for further analysis.

Floodplain Deposition Monitoring

Sediment deposition was measured using AstroTurf® mats that installed on floodplain surfaces that were relatively flat and away from major obstructions (Lambert and Walling 1987). The AstroTurf® mats were 1-by-1 ft and were secured using metal pins driven into the ground on each corner. The mats were installed between March and May 2007 and col-lected in May 2008. Although some studies have focused on sedimentation during individual events (Steiger et al. 2001), for this study the total effect of sediment deposition over an an-


nual period was judged to be more important than inter-flood variations. Measuring deposi-tion over a year integrates the effects of floods that deposit sediment and subsequent floods that may erode sediment, resulting in the net deposition rate.

Suspended Sediment Monitoring

The sediment transported in the watershed was monitored from February 2007 through March 2008 using a series of siphon samplers, which were recommended by KDOW based on their utility in other monitoring projects and because they collect samples automatically, reducing cost and the risk to personnel in sampling during flood events. US U-59 single-stage suspended sediment samplers (FISP 1961; Edwards and Glysson 1988) were modified to use Nalgene bottles instead of glass, and the exhaust tube was raised to limit contamina-tion during high flows. The modifications to the original design were not expected to influ-ence sampler performance. To reduce the risk to the samplers during floods and to minimize snagging of debris, all sample bottles were housed in a PVC pipe with inlet tube exposed, following Gray and Fisk (1992). Typically, five samplers were arranged in a single array, and the PVC pipe was attached to a bridge pier, where available (Figure 2.13), or to a sturdy tree (Figure 2.14). The lowest bottle was installed approximately 1 ft above the elevation of the downstream riffle crest to sample during floods, when sediment is typically transported (Knighton 1998). Data from a total of 10 flood events that reached that stage or higher were captured during the 13.2-month sampling period. Grab samples also were collected on an opportunistic basis from the center of the stream channel to evaluate the representativeness of samples collected adjacent to the stream bank (from the single stage samplers) relative to the flow in the center of the channel (grab samples).

The limitations of the US U-59 sampler are listed by Edwards and Glysson (1999). Those most relevant to this study are

Figure 2.13 Suspended sediment sampler near the confluence of Goose Creek and Benson Creek.

Figure 2.14 Suspended sediment sampler at Goose Creek near I-64.


1. Samples are collected at or near the stream surface. 2. Samples are usually obtained near the edge of the stream or near a pier or abut-

ment. 3. Covers or other protection from trash, drift, and vandalism often create unnatural

flow lines at the point of sampling. 4. The device is not adapted to sampling on falling stages or on secondary rises. 5. Sometimes the sediment content of the sample changes during subsequent sub-

mergence. 6. Under high velocities, circulation of flow into the intake nozzle and out the air

exhaust can occur. This will increase the concentration of coarse material in the sample and can make the sample concentration several orders of magnitude high-er than stream concentration.

Limitations 1-3 are most significant where sand is a major component of the suspended sediment load (see Vanoni 2006, p.46-50), so in Goose Creek these can be considered minor limitations. To minimize the vertical and lateral variations in suspended sediment concentra-tion (Limitations 1 and 2), samplers were installed downstream of bridge or culvert (where possible). The contraction of flow through the bridge or culvert will create turbulence, in-crease mixing and minimize the variation in sediment concentration. In addition, “the as-sumption that suspended sediment of fine particles is well mixed throughout the water col-umn is widely used and has been approved in several individual rivers and agricultural drains” (Walling and Teed 1971; Carling 1984; Kuhnle et al. 2000; and Gao et al. 2007, as cited in Gao 2008, p.245). Limitation 3 is difficult to avoid but was reduced somewhat by the enclosure of the sample bottles in the PVC pipe. Limitation 4 may be a significant cause of error in suspended sediment load estimates. To overcome this limitation, a different sampling strategy would be required, such as using continuously recording turbidity sensors or utilizing automated pump samplers. Limitations 5 and 6 were minimized by constructing the samplers with much longer outlet tubing than the original US U-59, hence increasing the hydraulic head needed to create conditions where recirculation would occur.

All bottles were emptied following each rainfall event and were replaced with clean bottles. If more than one event occurred in a single day, however, the bottles were not emptied after the first event, and those events were not included in the dataset. At each site visit, the inlet tubes were checked for blockages and were cleaned if necessary. Any debris that had accumulated around the sampler array was removed. The seals around the top of each bottle were checked and re-sealed if necessary. All water samples were refrigerated upon return from the field and held for less than 120 days (Knott et al. 1993) prior to analysis.

Stage and Discharge Measurements

Measurements of water depth and atmospheric pressure were logged to correlate the stage of flow with each suspended sediment sample. At each sampler location, a submerged Model 3100 Levelogger® Gold was suspended in a PVC pipe secured to a bridge or tree. A Barologger® was secured to a tree at the Ballard Branch site above the highest possible wa-ter level at the site. The submerged loggers measured the total pressure (water depth and at-mospheric pressure), while the Barologger® measured and logged the atmospheric pressure at the same times and intervals as the submerged loggers. The instruments have an accuracy of 0.1% of full scale (±0.015 ft for the Levelogger® Gold and ±0.003 ft for the Barologger®).


The Model 3100 Levelogger® Gold can store 40,000 readings, allowing for extended de-ployment for obtaining high-flow data. Logging intervals were set (using the Solinst soft-ware) to 5 minutes at all sites; this interval was short enough that the water surface change would typically be less than 0.2 ft between readings.

Discharge was measured using a handheld ADV (for wadeable flows) or a boat-mounted ADCP (for non-wadeable flows). The measurement of discharge followed USGS guidelines (Wahl et al. 1995) except when stage was observed to be changing rapidly: meas-urements were then taken over a shorter duration than recommended.

2.7 MONITORING DATA ANALYSIS

Sediment Production from Bank Erosion

Blue-Line Channel Erosion The average erosion rate for each bank pin site on blue-line assessment reaches was de-

termined by weighting the rate measured at each erosion pin by the proportion of the bank represented by each of the pins. Typically, the top pin covered about 50 percent of the height of the bank, whereas the lower two pins covered 20-30 percent each. The weighted average of the three pins was used in estimations of sediment production. The annual rate of erosion, er (ft/yr), was determined by dividing the length of exposed erosion pin by the duration of field deployment in days and then multiplying by 365; final results represent the erosion rate between September 2007 and January 2009.

To estimate erosion rates for banks not monitored with pins, an empirical relationship between the annual erosion rate (er) and BEHI and NBS indices was developed. Because few BEHI indices in the “extreme” risk rating range were recorded during the geomorphic assessment, “extreme” and “high” risk ratings were grouped together. Likewise, “very low” and “low” risk ratings were combined. The relationship between annual erosion rate and BEHI risk ratings was derived for high, moderate, and low NBS risk ratings using ordinary least-squares regression. The annual erosion rate for each bank pin site on blue-line assess-ment reaches was plotted as a function of BEHI risk rating for each NBS risk rating, and best-fit lines for each category were regressed in the form of linear functions. Erosion rates then were estimated for all other eroding banks mapped in the geomorphic assessment by applying these linear functions to their BEHI and NBS risk ratings.

The erosion rates were used to estimate the volumetric rate of sediment produced from each eroding bank, VB (ft3/yr), which was estimated from

VB = (LLB x ELB x HLB x er) + (LRB x ERB x HRB x er) (2.1)

where the subscripts LB and RB denote the left and right bank, respectively, L (ft) is length of assessed bank, E is the percentage of the bank eroding, H (ft) is bank height, and er (ft/yr) is the annual erosion rate. The volumetric rate of sediment production estimated from each bank was summed for all of the assessed reaches.

The mass of sediment produced from bank erosion per unit length per year, mB (tons/ft/yr), was then estimated from

𝑚𝑚𝐵𝐵 = ∑𝑉𝑉𝐵𝐵×𝜌𝜌𝑏𝑏𝐿𝐿𝑅𝑅

(2.2)


where ρb (tons/ft3) is the average bulk density of bank sediments and LR (ft) is the length of the reach.

Unmapped Channel Erosion Sediment production from unmapped channels was estimated using a GIS-generated

channel network and field data. GIS Channel Network Generation. In the Goose Creek watershed, many headwater

channels not shown as blue-line streams on USGS topographic maps are distinct water-courses with eroding banks. Estimating the sediment production contribution from bank ero-sion requires an estimate of the extent of these unmapped channels. The starting point for these channels, and hence the channel network, is the channel head. By determining the drainage area, or flow accumulation area, at which channel heads occur, a channel network can be generated using standard GIS routines. These generated networks can then be com-bined with field measurements of bank erosion to estimate sediment production rates for the networks.

Drainage areas of each channel head were measured from 30-ft resolution DEMs. The drainage areas of all channel heads were tabled, and summary statistics (mean, median, mode, standard deviation) were calculated. Using the channel head summary statistics as the points at which the channel network begins, channel networks were generated in ArcGIS Spatial Analyst. The channel network generation was performed on a 30-ft resolution DEM for the Goose Creek watershed according to the following steps:

1. Calculate flow direction for each cell (Jenson and Domingue 1988). 2. Calculate flow accumulation for each cell (Jenson and Domingue 1988). 3. Identify the flow accumulation threshold value that represents the start of the

channel network, and designate all cells below this value as channel. 4. Calculate stream order (Strahler 1957). 5. Convert raster dataset to vector. 6. Estimate length of channel network.

A number of channel networks were generated to see which best approximated the real channel network, and hence provided the most accurate measure of bank length. The flow accumulation area for the channel heads was changed in each network while all other pa-rameters were kept constant. The channel head drainage areas ranged from less than 0.5 acres to more than 6 acres. The mean, median, and mode of all channel heads were used as initial flow accumulation areas. The mean, median, and mode ±1 standard deviation also were used.

From the drainage network generated using the maximum channel head area, the streams were ordered according to the Strahler (1957) method, and all first- and second-order streams were identified. The third- and higher-order stream reaches corresponded to the blue-line streams very closely and therefore were not included in the analysis of un-mapped channels.

For the three drainage networks generated using the maximum, minimum, and mean channel head areas, drainage density, Dd (mi/mi2), the total length of channel per unit area (Horton 1945), was estimated from


dd A

D L∑= (2.3)

where ∑L is the total channel length in a basin of area Ad. The drainage density of the blue-line streams for Goose Creek watershed was also estimated in order to compare it with the densities of the three generated channel networks.

Field Measurement Data Reduction. The lengths of eroding banks were estimated in GIS from GPS readings collected in the field. The GPS points were overlaid on the generat-ed drainage network, and the Strahler (1957) stream order of each assessed reach was rec-orded. Average bank heights and average percentages of eroding bank length were estimated separately for first-order assessment reaches and for second-order assessment reaches. The averages were then multiplied by each stream order’s respective total channel length to es-timate an average percentage of eroding bank area for first-order streams and an average percentage of eroding bank area for second-order streams.

Sediment Production Rate Estimates. Because bank pin data were insufficient to devel-op BEHI curves for unmapped channels, a simper approach was adopted. First- and second-order channels were treated separately. For assessed reaches, a unit erosion rate, UER (ft3/ft/yr), was estimated from

𝑈𝑈𝑈𝑈𝑈𝑈 = 𝐻𝐻𝑎𝑎𝑎𝑎𝑎𝑎×𝐸𝐸×𝑒𝑒ℎ𝑤𝑤𝐿𝐿𝑟𝑟

(2.4)

where Have (ft) is the average bank height for all assessed first- or second-order streams, E (ft) is the length of assessed banks, ehw (ft/yr) is the headwater average erosion rate for all assessed first- or second-order streams, and Lr (ft) is the total reach length of assessed un-mapped channels. The erosion rate, ehw, was the weighted average of all erosion pin readings (n = 86) taken from sites with a drainage area of less than 3 mi2 (n = 29). The average bank height and the length of eroding bank were averages estimated from more than 10,000 ft of assessed unmapped channel reaches (5996 ft for first-order and 4391 ft for second-order).

The total mass of sediment produced by unmapped channels per unit length per year, mB (tons/ft/yr), was estimated from

mB = (ρb) (UER1st)(Lr-1st-order) + (ρb) (UER2nd)(Lr-2nd-order) (2.5)

where the lengths of first- and second-order streams, Lr-1st-order (ft) and Lr-2nd-order (ft), were measured from the drainage network generated using the mean drainage area.

BEHI and Erosion Rate Correlation The BEHI method was developed in Colorado (Rosgen 2001) and has been used pri-

marily in gravel- and cobble-bed streams in regions where bank erosion is caused primarily by shear stresses from flood flows. To test the applicability of this method to Goose Creek reaches, where weathering is a significant component of bank erosion processes, the BEHI parameters and NBS were tested for correlation with erosion rate using SPSS. In addition, a stepwise regression was used to ascertain which BEHI parameters were the best predictors of erosion rates. Stepwise regression (calculated forward using SPSS) involves starting with no variables and adding the variables only if they are significant. The most significant is added first, and then additional variables are added if they increase the strength of the rela-tionship with the independent variable (erosion rate, in this case).


Sediment Production from Upland Surface Erosion

Soil erosion models are a widely used method of estimating upland erosion rates be-cause instrumenting every hillslope and valley in a watershed is time- and cost-prohibitive. Use of soil erosion models without field measurements, however, is subject to great uncer-tainty and may produce results that are contrary to observed conditions (Trimble and Cros-son 2000; Reid and Dunne 1996). Therefore, field measurements of pond sediments were used to assess the accuracy of a GIS-based soil erosion model to estimate the total annual loads in the Goose Creek watershed attributable to eroded upland sediments.

Pond Survey Data The in situ bulk density, ρC (lb/ft3), of each sediment core was estimated from

ρ𝐶𝐶 = MCVC

(2.6)

where MC (lb) is the oven-dried mass of the core, and VC (ft3) is the in situ volume of the core. The mass was obtained after the samples were dried in the oven at 110°C for 24 hours. The in situ volume was used because (1) this volume was measured for many points, not just core locations, and (2) the in situ volume was easier to accurately measure than the volume after drying when the sediment core shape became very irregular. The bulk densities for submerged sediment cores in each pond were averaged to give ρsubm; the bulk density for the sediment toe at the pond inlet is denoted ρtoe.

The cross section data collected in the field were entered into an Excel spreadsheet, and two lines were generated at each cross section, one for the top of the deposited sediment lay-er and one for the bottom of the deposited sediment, representing the original land surface immediately after pond construction.

The cross-sectional data were then exported to AutoCAD together with the perimeter survey and data surveyed above the water surface. A triangular grid network (TIN) was gen-erated for both the top and bottom of deposited sediment using automated routines in the Autodesk Land Desktop Terrain Editor. The difference in volume between the two TINs was estimated in AutoCAD and represented the volume of deposited sediment. Separate TINS were generated for the sediment toe at the pond inlet, which was above the water sur-face. The volume of submerged sediment was then multiplied by ρsubm for each pond to es-timate the mass of submerged sediment in each pond. The above-water sediment mass was estimated in the same way using ρtoe values.

The upland sediment production rate for each pond, Sp (tons/ha/yr), was estimated from

𝑆𝑆𝑝𝑝 = (𝑀𝑀𝑇𝑇)𝐷𝐷𝐷𝐷×𝑇𝑇

(2.7)

where MT (tons) is the total mass of sediment deposited in and around the fringe of the pond, DA (ha) is the contributing drainage area, and T (yrs) is the deposition period. This upland sediment production rate is a net erosion rate: the difference between the rate of soil loss and the rate of soil deposition.

GeoWEPP Modeling The GeoWEPP interface was selected to analyze sediment production from upland sur-

face erosion because it is relatively easy to use, uses commonly available geo-spatial da-


tasets, and uses the widely-used and physically based WEPP model. The WEPP model has the advantage over the Universal Soil Loss Equation in that it models soil loss and soil dep-osition rather than soil loss alone. The upland sediment production rate, Sm, output by the GeoWEPP model is the net erosion rate: the difference between the rate of soil erosion (soil loss) and the rate of soil deposition. More documentation on the WEPP model is given in Flanagan and Nearing (1995); more documentation regarding the GeoWEPP interface is given in Minkowski and Renschler (2008).

The GeoWEPP simulation runs for a user-specified interval. The Goose Creek water-shed GeoWEPP simulations were run using 50 years of climate data from the Kentucky River Lock and Dam 4 climate station in Frankfort, which is the closest station available in the WEPP program’s climate dataset (Nicks et al. 1995). The other inputs for the GeoWEPP simulations were the 2001 National Land Cover Database (USGS 2008), soil types (NRCS 2009), and topography (USGS 30-ft DEMs). To run GeoWEPP, each soil type was convert-ed into a GeoWEPP soil file, which has various soil properties such as interrill erodibility, critical shear, effective hydraulic conductivity, percent organics, percent clay, etc. Similarly, the land cover type was converted into a GeoWEPP management file. Using field observa-tions, interviews with landowners, and the results of the pond surveys, the GeoWEPP soil file and GeoWEPP management files were calibrated to conditions in Goose Creek. Soil files were generally unmodified except to change soil types to “flaggy” where appropriate. Guidance on individual parameters came from the Soil Survey of Anderson and Franklin Counties, Kentucky (McDonald et al. 1985). The land cover management file required great-er modification: the default “fallow” land use, for instance, produced very high erosion rates not representative of fallow land in Goose Creek.

The GeoWEPP typically predicts soil loss and deposition rates from hillslopes and from channels. Because the channel routing/sediment transport model is not very sophisticated (Bill Elliot, pers. comm. 2009), however, only the hillslope component of the model was used. The output data from each hillslope was imported in an Excel spreadsheet, and the to-tal sediment production, Mhill, (soil loss minus deposition) was estimated for all hillslopes. The total mass of sediment produced from upland erosion, Mup, within each subwatershed was estimated as the sum of the Mhill values from all hillslopes. The modeled sediment pro-duction rate, Sm, was estimated by dividing Mup by the area of subwatershed. In total, 9.13 mi2 of the 10.32-mi2 watershed was modeled using GeoWEPP.

The upland sediment production rates estimated from the pond data were used to assess the accuracy of a GeoWEPP (Geo-spatial Interface for Water Erosion Prediction Project) model for the watershed. The sediment production rate predicted for each pond’s hillslope using GeoWEPP was plotted as a function of each upland erosion rate estimated from the pond surveys. An ordinary least-squares regression was calculated between the estimated (GeoWEPP) and observed (pond) data and was compared to the line of perfect agreement (x = y).

Floodplain Deposition

The sediment mats were collected after deployment, and a hose was used to wash the sediment into a bucket. Any sediment stuck on the mat was scrubbed off, and the washing water also went into the bucket. The water-sediment mixture was allowed to settle for 2-3 days, after which the supernatant was carefully removed. The remaining water was evaporated in an oven, and the mass of sediment was measured. The local rate of deposition


was then estimated by dividing the mass of sediment by the collection duration and the area covered by the mat.

Local measurements of deposition rates were used to develop a general classification of deposition sites and estimate the average deposition rate, D (tons/ha/yr), for each deposition category (Table 2.15). Deposition of fine sediment is controlled by the local flow velocity of overbank flows relative to the size of the sediment in transport, and valley gradient is an im-portant determinant of overbank flow velocity. For gullies and very small drainage areas, floodplain inundation was assumed to not occur; these were classified as zero deposition ar-eas. All other areas with high valley slopes were classified as low. A deposition class of moderate was assigned to reaches where the bank height:bankfull height ratio was less than 2.8 or the mean valley slope was less than or equal to 0.2 percent. A deposition class of high was assigned to reaches in the vicinity of stream crossings, where local backwater ef-fects are important; “high” was also assigned to reaches where the bank height:bankfull height ratio was less than 2.8 and the mean valley slope was less than or equal to 0.2 percent. All other reaches were classified as low or zero.

Table 2.15 Deposition Categories Deposition Class

Average Deposition Rate, D (tons/ha/yr) Criteria

Zero 0 Valley flat not inundated or not present; gullies Low 10.8 High valley slope AND high entrenchment Moderate 53.8 Low valley slope OR low entrenchment High 71.4 Upstream of crossing structure; low slope AND low entrenchment

The average deposition rates for each class were applied to all blue-line assessment reaches to estimate the total mass of sediment stored, Mdep (tons), on Goose Creek watershed floodplains and terraces from

Mdep = D x AVF (2.8)

where AVF (ha) is the area under which storage occurred, defined by

AVF = (WVF – WTOB) x LVF (2.9)

where WVF (ft), WTOB (ft), and LVF (ft) are the width of the valley flat, the width of the chan-nel, and the length of the valley reach, respectively.

Suspended Sediment Loads

Suspended sediment loads—the mass of suspended sediment transported in Goose Creek and its tributaries over a specified period of time—were estimated as the product of suspended sediment concentration and discharge. Suspended loads were estimated over an annual period to assimilate the variations that occur within single flood events, between dif-ferent flood events, and between different seasons. The suspended load at the mouth of Goose Creek was the watershed’s suspended sediment yield—the mass of suspended sedi-ment transported into Benson Creek from Goose Creek over a specified period of time.


Suspended Sediment Concentration Estimates Measurements of SSC were obtained using ASTM Standard Test Method D 3977-97,

Test Method A – evaporation (ASTM 2000).

Stage and Discharge Estimates A stage-discharge relation was derived using ordinary least-squares regression. Stage

measurements were compensated for atmospheric pressure using Solinst software and then were plotted as a function of discharge measurements. A best-fit line was regressed for the plot in the form of a second-order polynomial or natural logarithmic equation. From the stage-discharge relation, a discharge was estimated for each stage reading.

To increase the statistical confidence of the stage-discharge relationship developed from data collected for a period of 2 years or less, discharge measurements during large floods need to be recorded. Instruments for such measurements were not available during the data collection phase, although they are available now (e.g., Sontek Argonaut SW; RDI Teledyne V-ADCP). The USGS also typically recommends more discharge readings be collected for a stage-discharge relationship (10 per year) (Rantz et al. 1982) than were collected in this pro-ject (4-8 per site). One objective of that recommendation is to incorporate the effects of con-tinuous changes in channel morphology due to deposition and erosion. Goose Creek reaches, however, have bedrock beds and cohesive banks, and channel changes are minor relative to, for example, an alluvial sand-bed river. Because of the very stable bedrock grade control, the field measurements of stage and discharge were used in preference to modeled values with unknown accuracy.

Stage and Suspended Sediment Concentration Analysis An SSC-stage relation was derived using ordinary least-squares regression to evaluate

the relationship between the SSC and stage data. The minimum and maximum SSC esti-mates from a 12-month period for each bottle were plotted as a function of stage measure-ments. A best-fit line in the form of a second-order polynomial or natural logarithmic equa-tion was regressed for the minimum annual SSC measurements, and a second best-fit line was regressed for the maximum annual measurements. A third best-fit line for each site was regressed for all data from a 12-month period, and a fourth best-fit line was regressed for all data from all sites for the 12-month period. Finally, all SSC values for each bottle for a 12-month period were averaged, and the standard deviation was calculated to assess the var-iability of SSC at a given bottle over the measurement period.

Sediment Load Estimates From the stage-discharge relation, discharge values were estimated for the stage at

which each bottle was inundated. Sediment rating curves for each site then were derived by plotting each bottle’s annual minimum and maximum SSC measurements as functions of those discharge values. Use of the annual minimum SSC values provided a smooth relation-ship between SSC and discharge, whereas plots of the annual maximum SSC values and dis-charge showed considerable scatter and no discernible relationship. The rating curves de-rived using the annual minimum SSC values also produced more modest increases with discharge compared to the regression curves derived using the annual maximum SSC values. Therefore, use of the annual minimum SSC value curves was assumed to provide the better lower-bound estimate of the actual suspended sediment load.


Sediment loads were estimated for each of the 10 flood events that were recorded over the 13.2-month sampling period. All flows that reached the elevation of the lowest sediment sample bottle (approximately 1 ft above the elevation of the downstream riffle crest) were sampled; for flows that were less than or equal to those sampled by the lowest bottle, SSC was assumed to be zero. The loads for each event were estimated in 15-minute intervals from minimum measured SSCs and discharges from the stage-discharge relation; for moni-toring intervals without a reliable sample, a measured SSC could not be used, and SSC was derived from the sediment rating curve instead. Excluded samples were those with very high sediment concentrations that indicated a potential leak and those where the bottle had accu-mulated sediment from more than one flow event. For each 15-minute interval of the rising limb of the hydrograph, the minimum SSC for the interval was multiplied by the discharge corresponding to the stage at which the SSC sample was taken. That product was the esti-mate of the load for that interval. For each 15-minute interval of the falling limb of the hy-drograph, the sediment rating curve was used to estimate the load. The sum of the loads for each interval was the estimate of the total load for the flood event. The cumulative total of the estimates for any given sampling location over the year (i.e., the unit sediment load) was considered to be representative of the entire load transported at that location during that time. These estimates may be significantly higher or lower than the actual loads, however, both because flows below the lowest bottle were not sampled and because SSC is highly variable during flood events, and the single sample collected by a bottle for any given event is unlikely to be an accurate measure of the average concentration for the event. No flood events were captured in the summer during the sampling program. While this was probably due to a lack of runoff during that period, it may have been due to an undetected malfunc-tion in the monitoring equipment. Nevertheless, precipitation was low for the period, and the suspended sediment load of any unrecorded events would have been very minor.

3. Results and Discussion

3.1 WATERSHED GEOMORPHIC CHARACTERISTICS Reach- and Watershed-Scale Characteristics

No reference-quality reaches were identified in Goose Creek watershed. All reaches that were assessed showed significant signs of alteration. In many reaches of both Goose Creek watershed and the larger Benson Creek watershed, the channel is straight and aligned along the hillslope of one side of the valley. Unchannelized reaches were rarely observed and were typically close to the drainage divide. Other noted alterations included installation of stream crossings such as culverts, fords, and bridges; removal of riparian vegetation; and burial of headwater reaches. These impacts have altered the sediment delivery system, in-channel habitat, and hydrology, including persistence of flow. Throughout the watersheds, streams have low channel sinuosity; subdued riffle-pool topography; low habitat diversity; high, un-vegetated banks; and abandoned floodplain(s) or terrace(s) that are inundated only during large floods.

Following European settlement in the Bluegrass, hillslopes were cleared, and eroded soils accumulated to depths of several feet in many valleys (Parola et al. 2007). Much of the drainage network was straightened to provide more land for agriculture and, in the headwa-ters, to facilitate logging. Channel and floodplain modifications greatly reduced the capacity

Results and Discussion 39

of the watershed to store sediment relative to pre-settlement conditions. In Goose Creek wa-tershed, channel straightening and debris removal instigated channel incision and increased the sediment supply to the downstream network: as headcuts propagated upstream, they in-creased sediment supply by triggering bank erosion. The migration of headcuts through the upper reaches of the network also increased sediment supply by incising the channels closer to the ridgetops. Sediment that prior to settlement was stored on hillsides above the channel head, and hence was unavailable to the stream network, has been re-deposited downstream, where the material is accessible to the stream via bed and bank erosion (Knox 1987; Trimble 1981; Jacobson and Coleman 1986). Channels that were straightened and aligned against the side of the valley often destabilized the hillslope, leading to localized mass failures that sup-plied both coarse and fine sediment. Channel incision also reduced the frequency of over-bank flooding and associated fine sediment deposition and storage on floodplains.

The downstream-most reaches of some tributaries that traverse the valley of Goose Creek and Ballard Branch are incising through post-settlement alluvium to the base level of the incised main stem. The banks in these reaches are relatively high compared to the banks of upstream reaches. Other locations with very high banks in the watershed are abandoned mill ponds and farm ponds. These ponds were built with a dam at the downstream end that trapped sediment from the upstream drainage area and stored it within the bottom of the pond and in the channel immediately upstream. Many of these dams have been breached, and the stored legacy sediments and the spoil from the breached earth dam are being re-leased to the stream channels.

Most reaches in both the Goose Creek main stem and its tributaries have incised to bed-rock. The underlying interbedded limestone-shale units of the Eden Shale Belt weather rap-idly, and as a result, the bedrock breakdown rate is high (Weir et al. 1984), providing a source of course material for riffle formation. The largest size fraction of riffles are com-posed of coarse (>36 mm intermediate diameter), platy material that is locally sourced from the degrading bedrock. The location of riffles is controlled by the availability of broken bed-rock to form riffle framework material and by the presence of obstructions such as bends, tree roots, and channel boundary contractions to create the reduction in bed stress necessary to prevent transport of cobble- and boulder-sized materials that provide the framework of the observed riffles. Riffle-to-riffle spacing varies between 1 and 13.8 channel widths (Ta-ble 3.1). In sinuous reaches with relatively complex channel planform, the riffle frequency is greater than in straight, uniform reaches, where coarse-gained sediment deposition is lim-ited.

Stream banks are primarily composed of layers of consolidated silt and clay that are somewhat resistant to direct erosive effects of flood flows and can maintain steep, bare banks. The consolidated silts and clays may, however, undergo significant change in erodi-bility by weathering (Lawler 1986). The two principal weathering processes that have been observed in the Bluegrass are freeze-thaw (on banks with minimal vegetation) and desicca-tion (on banks with minimal vegetation or canopy cover) (Lawler et al. 1997). Freeze-thaw of bank materials throughout channel networks was noted in fieldwork conducted during winter months; this bank weathering process is responsible for producing large volumes of fine-grained sediment that remain loosely attached to the perimeter of the channel or fall and form a pile of loose unconsolidated material at the base of the bank. Extreme drying of the banks, observed during the summer drought of 2007, may also produce large volumes of sediment that behave similarly to the weathered material produced by freezing and thawing.


Table 3.1 Riffle Crest-to-Crest Distances Distance (ft) Distance (no. channel widths)

Reach ID Mean Median Min Max Mean Median Min Max GC1 98.7 79.5 42 251.4 2.6 2.1 1.1 6.6 GC2 206.9 159.9 91.5 451.6 5.4 4.2 2.4 11.9 GC4 183.3 193 29.6 276.2 7.3 7.7 1.2 11 GC5 71 73.1 27.2 106.5 3.7 3.8 1.4 5.6 BB1 98.5 82.3 64.1 154.3 3.8 3.2 2.5 6 BB3 102.8 89.2 67.3 135.3 7.9 6.9 5.2 10.4 BB5 82.7 82.8 41.6 152 7.5 7.5 3.8 13.8 BBT2 - lower 106.1 101.7 31.1 212.3 4.8 4.6 1.4 9.7 BBT2 - upper 90.4 85.7 29.1 181.2 5 5 2 10 BBT3 - lower 131 133.5 58.1 237 6.5 6.7 2.9 11.8 BBT3 - upper 81.3 67.6 15.7 190.9 5.1 4.2 1 11.9 WB1 113.3 118.9 31.4 176 4.7 5 1.3 7.3

These weathering processes have been noted in other environments (Lawler 1986), but the climate of Kentucky is particularly conducive to these forms of bank weakening and sedi-ment production.

Most banks are high and unvegetated, and although no mass failures were observed, eroding banks are common and widely distributed. Erosion is seldom pronounced in straight sections. More sinuous sections downstream of straight sections, however, usually have a rapidly eroding bank or series of banks. The rate of erosion is insufficient to cause rapid change in the channel planform or to undermine any structures. Fallen trees, which are often good evidence of rapid erosion and undermining of the banks, were observed only rarely, even in reaches where bankline trees are numerous. Undercut banks are rare, and although many reaches have banks with exposed roots, they are typically well above the low-flow wa-ter surface and hence provide no refuge in the channel and little protection to the banks.

The riparian corridor was alternately very wide (greater than 120 ft) and very narrow (less than 40 ft), especially where residential yards encroach on the stream corridor. Lawns and crops are present only over short distances, however, and native vegetation is abundant. The two most common human disturbances in the riparian zone are clear cutting for pasture or hay and roads. Very few intense disturbances were observed, such as row cropping near the stream or movement of soil by large machinery.

Sub-Reach-Scale Characteristics

Approximately 94 percent of the riffles in the assessment reaches were at least 25 percent embedded with silt and sand, and half of those were at least 50 percent embed-ded. Siltation of riffles was not restricted to individual tributaries, but was common through-out Goose Creek watershed (Figure 3.1). Embedded riffles were frequently found in reaches that also had unembedded riffles, indicating that the development of siltation was strongly influenced by local characteristics of channel and valley morphology. Riffle embeddedness was observed primarily in three types of locations:


Figure 3.1 Spatial distribution of embeddedness.

1. Immediately downstream of an eroding hillslope or high, weathering streambank:

a surficial crust of bank material loosened by weathering detaches and falls to the base of the streambank, washes to the base of the bank or into the channel by rainfall, or, in the lowest portion of the bank, washes directly into the water by wave action or minor increases in flow and stage. The fine sediments derived from weathered bank material are deposited in the channel when flow velocities are low, typically following periods of little or no precipitation. Low flow in the channel is capable of transporting the fine sediments only a short distance, and some of the sediments are deposited along the edge of the water and in other very low-velocity areas of downstream riffles. If weathering and transport of the fine material persists without a large flood to remove sediment, then accumulation may cover a substantial portion of the riffle or even the entire substrate. Algae, aquatic vegetation, and herbaceous vegetation growing in and along a riffle can enhance accumulation of sediment (Thorton et al. 1997).

2. Immediately downstream of the confluence of a tributary channel with another much larger channel: when rainfall produces runoff in a small tributary, it deliv-ers fine sediment to confluences with downstream larger channels. When flow velocity and depth in the larger channel downstream of the confluence does not respond significantly to the rainfall event either because of the longer response time of the larger channel’s watershed or because of non-uniform rainfall, the larger channel may not have sufficient flow to transport the fine sediment sup-plied by the tributary. The sediment therefore deposits near the confluence and in downstream riffles. Deposits in channels were particularly pronounced down-


stream of confluences of small tributaries with bare, weathering banks where large volumes of sediment accumulated following freeze-thaw cycles and then were transported into the larger downstream channels during subsequent small storm events (Croasdaile and Parola 2011).

3. Upstream of channel obstructions or contractions that promote sediment deposi-tion by creating backwater during floods: channel morphological features such as bends with a small radius of curvature, channel boundary contractions, or large woody debris jams; and structures such as culverts, weirs, or bridges. Channel obstructions can reduce velocities sufficiently for some fine sediment to deposit (Gurnell and Sweet 1998).

Several types of riffle siltation were observed in these locations: blanket covering of the streambed by silt (Figure 3.2), blanket covering of the streambed by sand (Figure 3.3), intru-sion of silt into a cobble bed (Figures 3.4 and 3.5), intrusion of sand into a cobble bed (Fig-ure 3.6), as well as the effects of algal mats that might induce or be the result of silt deposi-tion (Figure 3.7).

None of the other point-scale RBP scores showed any systematic trends according to location in the watershed (Figures 3.8-3.11). Small, steep tributaries and larger main stem channels showed all conditions from optimal to poor for all five parameters, and transitions from poor to optimal or vice versa occurred over very short distances. The habitat scores for 80 percent of assessed reaches were suboptimal or marginal for epifaunal substrate, embed-dedness, and sediment deposition (Table 3.2).

Figure 3.2 Blanket covering of riffle sediments with silt, Ballard Branch.


Figure 3.3 Blanket covering of riffle sediment with sand, Ballard Branch.

Figure 3.4 Cobble bed with silt intrusion, Ballard Branch.


Figure 3.5 Cobble bed with silt intrusion, Ballard Branch.

Figure 3.6 Cobble bed with interstices filled with sand, Ballard Branch.


Figure 3.7 Siltation can aggravate and be aggravated by growth of algae. This occurred during late spring before leaf-out and during mid-summer prior to the cessation of base flow.

Figure 3.8 Spatial distribution of epifaunal substrate quality.


Figure 3.9 Spatial distribution of flow status.

Figure 3.10 Spatial distribution of sediment deposition.


Figure 3.11 Spatial distribution of velocity/depth combinations.

Table 3.2 Distribution of RBP Sub-Reach-Scale Parameter Scores for All Assessment Reaches Percentage of Reaches Scoring in Each Category

Parameter Optimal Suboptimal Marginal Poor Epifaunal substrate 9.4 63.4 21.8 5.4 Embeddedness 5.4 47 38.1 9.4 Velocity/depth 5.4 37.1 43.6 13.9 Sediment deposition 10.9 51.5 32.7 5 Channel flow status 50 40.1 9.4 0.5

The scores for channel flow status were optimal for most reaches but marginal for ve-locity/depth. Channel flow status had little diagnostic value during the winter 2006/2007 RBP assessment period, as it exhibited little variation within the reaches or between subwa-tersheds; most reaches had flow. During late summer, however, most reaches had little or no flow (see below, Hydrologic Condition), and the amount of habitat available to aquatic or-ganisms was extremely limited. The velocity/depth scores primarily reflect the prevalence of bedrock substrate, which limits the formation of deep pools. Often very short riffles (fast, shallow flow) transitioned into glides (slow, shallow) with no intermediate velocity/depth combinations. Occasionally, deep, slow flow was encountered, typically in scour holes around large tree roots. Culverts and other crossing structures create deep scour pools that are otherwise rare in the watershed.


Hydrologic Condition

The vast majority of reaches within Benson Creek and Goose Creek watersheds, includ-ing reaches draining more than 70 mi2, were dry during the assessment of hydrologic condi-tion in September 2008, and they remained dry in October (Figures 3.12 and 3.13). Only two of the assessed reaches in Benson Creek watershed were found to have a perennial flow re-gime: the lower reaches of Benson Creek, and the lower reaches of North Fork North Ben-son Creek. The rest of the watershed, including Goose Creek and its tributaries, had inter-mittent or ephemeral flow regimes. The Goose Creek reach immediately upstream of the confluence with Benson Creek had regular pools with water but no flow, and pools were in-creasingly dry upstream of that short reach.

The absence of base flow indicates that groundwater is not being supplied to the stream channels during the dry period. This disconnection between the groundwater and the chan-nels is a result of the extensive straightening and relocation of the channel to one side of the valley, where the bedrock is very likely at a higher elevation than in the middle of the valley. As the water table falls during the summer and its boundaries recede toward the lower bed-rock at the middle of the valley, it becomes increasingly disconnected from the channel to the side. Groundwater from the adjacent hillside is insufficient to supply sustained flow to the channel, and the channel dries out. Even in instances where the stream channel is in the center of the valley but has incised to bedrock, the stream becomes dry in the summer except in isolated pools because the stream bed elevation, which controls the water table elevation, is too low to provide for enough groundwater storage to sustain flows through the dry peri-od. Locations where the stream crosses the valley from one side to the other are often the lo-cation for the pools that hold water for the longest period of time.

Figure 3.12 Distribution of hydrologic condition in Benson Creek and Goose Creek watersheds.


Figure 3.13 (a) North Fork North Benson Creek looking downstream toward confluence with North Benson Creek. Drainage area at this site is 8.1 mi2.

(b) Benson Creek looking downstream from KY-1005 bridge (Devils Hollow Road). Drainage area at this site is 101 mi2.

The disconnection between the stream bed and the water table that was observed in

Benson Creek and Goose Creek watersheds has several water quality and habitat implica-tions, some of which may be more detrimental to aquatic communities than the documented sedimentation/siltation impairment. Nutrient uptake and processing are reduced: tree roots are usually above the water table and cannot draw nutrients from it, and valley soils are rare-ly saturated, which limits denitrification and pollutant removal (Pinay et al. 1995). Increas-ing groundwater saturation of floodplains could therefore be an effective BMP for reducing nonpoint source pollutants. Drying of the channel also can lead to a reduction in aquatic and vegetative species diversity, as species with low tolerance suffer extensive mortality (Miller and Golladay 1996; Boulton 2003). Incorporation of hydrologic data and its effects on spe-cies mortality into biological assessments could improve the effectiveness of impairment de-terminations and management strategies.

3.2 SEDIMENT PRODUCTION AND STORAGE

Bank Erosion

The erosion pin monitoring results (Tables 3.3 and 3.4) showed a wide degree of varia-bility, from an annual erosion rate of over 1 ft to a site where the erosion pin was buried (negative erosion rate). At all of the sites, the erosion pins remained in place, and no mass movements (bank failures) had occurred. Repeated site visits during the period of measure-ment confirmed that most erosion was relatively gradual, although periods following repeat-ed freeze-thaw cycles produced the highest volumes of sediment (Figure 3.14).


Table 3.3 Annual Erosion Rates for Blue-Line Assessment Reaches

Reach ID Latitude Longitude

Drainage Area (mi2) Bank NBS BEHI

Erosion Rate, er (ft/yr)

BB2 38.1491 –85.0465 2.45 L Moderate High 0.15 BB2 38.1490 –85.0464 2.45 R Moderate Low 0.15 BB2 38.1481 –85.0402 2.62 R Low High 0.49 BB2 38.1481 –85.0432 2.56 R Moderate Moderate 0.09 BB3 38.1522 –85.0488 0.75 L Low Moderate 0.57 BB4 38.1493 –85.0563 1.18 L Moderate Moderate 0.19 BB4 38.1493 –85.0563 1.18 R Low Moderate 0.06 BB4 38.1487 –85.0580 0.89 R Very high High 1.16 BB4 38.1480 –85.0606 0.83 L Moderate High 0.07 BB4 38.1479 –85.0605 0.83 R Moderate Moderate 0.12 BB5 38.1475 –85.0616 0.56 R Moderate Extreme 0.38 BB5 38.1447 –85.0633 0.44 L High Moderate 0.27 BB5 38.1444 –85.0634 0.43 L Very low Moderate 0.06 BBT1 38.1507 –85.0382 0.83 L Low Very high 0.66 BBT2 38.1714 –85.0464 << 0.1 R Low Moderate –0.02 BBT2 38.1687 –85.0446 < 0.1 R Moderate Moderate 0.34 BBT2 38.1582 –85.0435 0.56 L Moderate Very high 0.42 BBT2 38.1580 –85.0435 0.56 L Low Low 0.33 BBT3 38.1572 –85.0535 0.58 L Low Low 0.62 BBT3 38.1555 –85.0520 0.68 L High High 1.28 BBT3 38.1555 –85.0520 0.68 L Moderate High 0.66 BBT3 38.1522 –85.0488 0.75 L Low High 0.57 BBT3 38.1520 –85.0488 0.79 L High High 0.47 BBT6 38.1494 –85.0657 < 0.1 L Low Very low 0.10 BBT6 38.1493 –85.0662 < 0.1 L Very low Low 0.36 BBT6 38.1489 –85.0630 0.24 L High High 0.54 BBT6 38.1479 –85.0613 0.26 L High Very high 0.33 GC1 38.1557 –85.0117 10.15 L Moderate High 0.25 GC1 38.1557 –85.0116 10.15 R Moderate Moderate 0.20 GC2 38.1542 –85.0191 7.91 R Moderate High 0.15 GC3 38.1646 –85.0350 < 0.1 L Low High 0.12 GC3 38.1512 –85.0249 6.17 R Moderate Moderate 0.10 GC3 38.1512 –85.0249 6.17 L Low Moderate 0.10 GC3 38.1494 –85.0294 6.00 L High Moderate 0.10 GC3 38.1472 –85.0313 5.95 L High High 0.31 GC4 38.1403 –85.0390 1.93 R Low Moderate 0.07 GC5 38.1339 –85.0421 0.87 R Moderate Very high 0.70 GC5 38.1280 –85.0416 0.50 R High Moderate 1.21 GCT2A 38.1641 –85.0222 1.04 R High High 0.61 GCT2A 38.1579 –85.0161 1.4 R Moderate High 0.35 GCT2B 38.1654 –85.0236 0.76 R Moderate Moderate 0.14 GCT2C 38.1669 –85.0283 0.67 R High High 0.23 GCT3 38.1536 –85.0234 0.43 L Moderate Very high 1.06 GCT4 38.1354 –85.0442 0.70 L [trib] Extreme High 0.51 WB1 38.1498 –85.0230 1.11 L Low Moderate 0.17 WB2 38.1331 –85.0303 0.36 R Moderate High 0.56 WB2 38.1287 –85.0308 < 0.1 L Moderate High 0.37 WB2 38.1258 –85.0318 << 0.1 R Low High 0.04


Table 3.4 Summary of Erosion Pin Results

Erosion Rate, er (ft/yr)

Mean 0.37 Median 0.32 Min –0.02 Max 1.28 Std Dev 0.32

Figure 3.14 Line of erosion showing where weathered material had been removed by recent flood event. The material in the upper portion of the bank was barely attached and was easily dislodged.

Erosion Rate and BEHI Parameter Correlation The empirical relationship between erosion rate and BEHI-NBS ratings is poorly de-

fined for the data collected from Goose Creek (Figure 3.15). Although it suggests a trend for increasing erosion rates with increasing BEHI-NBS, the strength of the relationship, as indi-cated by the coefficient of determination, R2, is low. Some of the BEHI parameters (includ-ing NBS) correlated strongly with erosion rate while others did not (Table 3.5). The four pa-rameters that are significantly correlated (p ≤ 0.005) with erosion rate are near bank shear stress, bank angle, weighted root density, and root depth/bank height ratio. Root depth/bank height is more strongly correlated with erosion rate than weighted root density is, indicating that vegetation type is important: shallow rooting grasses have less impact than tree roots even if the tree roots’ spatial coverage of the bank is not as wide. Bank height did not corre-late significantly with erosion rate. In part, this is because mass movements were not ob-served to have occurred: mass movements in stream banks are strongly controlled by the bank height, which needs to attain a critical value before failure occurs (Simon et al. 1999).


Figure 3.15 Empirical relationships between erosion rates and BEHI ranking for Goose Creek watershed.

Table 3.5 Correlation Matrix of BEHI Parameters Correlation Coefficient (r) and Level of Significance (p)

BEHI Parameter Ann

ual e

rosi

on

rate

(ft/y

r)

NB

S nu

mer

ic

Oth

er

cons

ider

atio

ns

Surf

ace

pr

otec

tion

Ban

k an

gle

Wei

ghte

d ro

ot

dens

ity

Roo

t den

sity

%

Roo

t dep

th/

bank

ht

Ban

k ht

/ ba

nkfu

ll ht

Ban

k he

ight

NBS numeric r 0.401 p 0.005 Other considerations r 0.151 0.001 p 0.309 0.993 Surface protection r –0.164 –0.155 –0.008 p 0.27 0.297 0.957 Bank angle r 0.468 0.245 0.376 –0.401 p 0.001 0.098 0.009 0.005 Weighted root density r –0.438 –0.248 –0.085 0.324 –0.298 p 0.002 0.093 0.57 0.026 0.042 Root density % r 0.016 –0.186 –0.019 0.221 –0.045 0.684 p 0.915 0.21 0.899 0.135 0.764 0 Root depth/bank ht r –0.491 –0.022 –0.19 0.125 –0.285 0.473 –0.172 p 0.000 0.881 0.2 0.403 0.052 0.001 0.248 Bank ht/bankfull ht r 0.022 0.091 0.064 –0.221 –0.072 –0.235 –0.202 –0.128 p 0.884 0.545 0.67 0.136 0.629 0.113 0.173 0.39 Bank height r –0.118 0.229 –0.122 –0.221 –0.125 –0.152 –0.244 0.137 0.733 p 0.428 0.122 0.415 0.135 0.403 0.309 0.099 0.357 0 Drainage area r –0.336 –0.073 –0.312 N/A –0.31 –0.051 –0.298 0.333 0.007 0.53 p 0.036 0.657 0.053 N/A 0.055 0.759 0.065 0.038 0.968 0.001

R² = 0.015

R² = 0.339

R² = 0.017

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

0 5 10 15 20 25 30 35 40 45 50

Eros

ion

rate

(ft/

yr)

BEHI (total)

High and very high NBSModerate NBSLow and very low NBS

High/very high

Moderate

Low/very low


The bank height ratio was also of limited importance in Goose Creek. In many cases, this is because the majority of reaches surveyed were incised, and hence, this variable had little variation. Reaches where the channel was not incised had a bank height ratio close to unity; they rarely had eroding banks and therefore were not included in the dataset.

Surface protection was not correlated with erosion rate (r = −0.164, p = 0.27). At most sites, bank protection was not observed. Where bank protection was present, such as large cobbles or boulders in the bed, insertion of erosion pins was not possible, and erosion rates were not measured. Hence, surface protection was not well accounted for by the field meth-ods. Other considerations included bank and bed materials. Bank materials also did not prove to be a particularly important predictor for erosion rates. This is because bank materi-als did not change appreciably in Goose Creek. Bed material was commonly bedrock, often present at the toe of the bank. It varied locally from thinly bedded shale to thinly bedded limestone but was generally consistent. Above the bed material, the lower bank material was commonly a clay-gravel mixture that was cemented and did not increase the BEHI. The dominant upper bank material was a silty clay loam or a silt loam, and this was consistent between sites (Figure 3.16). The lack of sand-sized bank material is due to the local geology, and its absence reduces the variability in BEHI risk ratings.

The stepwise regression that was used to ascertain which BEHI parameters were the best predictors of erosion rates indicated that bank angle and weighted root density explain most of the variation in erosion rates. Addition of the other parameters to the regression did not increase the strength of the statistical relationship.

The correlations of BEHI variables with erosion rate do not necessarily indicate causali-ty. In fact, the opposite is probably true: past bank erosion has probably influenced the BEHI parameters by shaping the bank morphology. Lack of vegetation and steep bank angles are

Figure 3.16 Typical bank composition in Goose Creek watershed: primarily silt-clay above a dense clay-gravel basal layer.


as likely to be the result of high erosion rates as they are to be the cause. Banks with steep faces are often that way because they have been eroded. The cohesive soils in Goose Creek permit a steep bank to persist after multiple erosion events. Likewise, vegetation is inversely proportional to erosion rate: the greater the weighted root density, the lower the erosion rate. This relationship also indicates past events: banks that are rapidly eroding will not have much vegetative cover because the vegetation has been eroded more quickly than new vege-tation can colonize the bare soil. Hence, the BEHI method is better applied as an index of past response to erosion rather than a predictor of future erosion. Over short periods of time (1-5 years), however, the sites of high bank erosion in the past can be expected to exhibit high rates of erosion in the future. This is especially true where even the most rapid bank erosion rates are on the order of 1-2 ft per year, and channel morphology is not dramatically altered by bank erosion. In streams where the most rapid bank retreat is on the order of 10-20 ft per year or greater, the BEHI variables may not predict future erosion rates, as channel morphology is changing too rapidly.

Blue-Line Channel Erosion The total annual mass of sediment produced by blue-line stream bank erosion was

1255 tons. The distribution of reaches with the highest unit mass erosion (Table 3.6) did not

Table 3.6 Sediment Produced by Blue-Line Stream Bank Erosion in Goose Creek Watershed

Reach ID

Assessed Length

(ft)

Blue-Line Length, LR

(ft)

DA (downstream)

(mi2)

DA (upstream)

(mi2)

BEHI Volume, VB

(ft3/yr)

Unit Mass Erosion, mB (tons/ft/yr)

GC1 2376 2376 10.32 10.14 499.9 0.009 GC2 3361 3361 8.09 7.89 611.2 0.008 GC3 4323 4323 6.19 5.95 1657.2 0.017 GC4 5134 5134 2.19 1.65 807.4 0.007 GC5 2915 2915 0.92 0.68 266.5 0.004 GC6 4379 4379 0.5 0.11 293.9 0.003 BB1 1459 1459 3.74 3.56 324.8 0.010 BB2 3226 3226 2.67 2.44 718.2 0.010 BB3 2847 2847 1.59 1.18 655.7 0.010 BB4 1525 1525 0.92 0.83 1149.9 0.033 BB5 2467 4471 0.56 0.12 1505.6 0.026 GCT1 6858 6858 0.57 0.1 569.0 0.004 GCT2A 4607 4607 1.47 1.03 1144.1 0.011 GCT2B 1940 6292 0.77 0.67 510.1 0.011 GCT2C 1014 3276 0.33 0.27 256.8 0.011 GCT2D 2974 4631 0.18 0.11 246.7 0.004 GCT3 5934 5934 0.49 0.12 728.0 0.005 GCT4 4379 7525 0.72 0.19 1740.0 0.017 BBT1 3280 3280 0.15 0.1 743.4 0.010 BBT2 9571 9571 0.89 0.1 2169.2 0.010 BBT3 8250 10201 0.84 0.1 1869.8 0.010 BBT4 3310 3310 0.3 0.12 0 N/A BBT5 3236 3236 0.25 0.11 2499.6 0.033 BBT6 1978 2138 0.26 0.1 1651.5 0.036 WB1 3958 3958 1.2 0.88 485.6 0.005 WB2 6181 6181 0.74 0.1 758.4 0.005 WBT1 2548 2548 0.14 0.1 312.6 0.005 Total 104,030 119,562 10.32 * Estimated from volume per unit length in adjacent reach.


follow an identifiable pattern. The highest rates were found in two locations: in Ballard Branch along the main stem in BB4, which had both high banks and a sinuous planform, and in one tributary, BBT6, which had very high banks for such a small drainage area. Because the highest rates of sediment production from bank erosion were not located in a consistent area or part of the watershed, management strategies would have to be local.

Unmapped Channel Erosion Mapping of channel heads in Goose Creek indicated that the channel network often

starts a long way from the blue-line streams and that many channels are not recorded on 7.5-minute topographic maps. An estimate of the percentage of the total drainage network that is represented by blue-line channels is dependent on the method used to estimate the “real” channel network in GeoWEPP (Table 3.7). The drainage network shown by blue-line streams represents less than 24 percent of the total drainage network generated using the maximum observed channel head drainage area. They represented 12 percent of the total drainage network generated using the mean drainage area, which had a drainage density very similar to that of the observed network.

Table 3.7 Estimated Length of Goose Creek Watershed Channel Network

Channel

Drainage Head Area Length of Network

Drainage Density, Dd

Blue-Line Stream (%

(ft2) (ha) (ft) (miles) (mi/mi2) of watershed) Minimum 2700 0.061 5,088,447 963.7 93.4* 2.46 Median 12,600 0.158 1,236,412 234.2 22.7 10.1 Mean 17,143 0.206 1,014,791 192.2 18.6 12.3 Maximum 83,700 0.828 541,036 102.5 9.9† 23.1 * Maximum drainage density estimated from minimum channel head drainage area. For a given valley network, the closer the channel heads

are to the drainage divide, the greater the extent of the channel network and, therefore, the greater the drainage density (Knighton 1998). † Minimum drainage density estimated from maximum channel head drainage area.

Use of the minimum channel head drainage area (i.e., the channel head closest to the ridge top in the field survey) to generate the stream network produced an unrealistic drain-age pattern (Figure 3.17). This example demonstrates that the minimum surveyed channel head should not be used for sediment erosion estimates, as it would vastly over-predict the channel network length (Type I error) and, hence, the supply of sediment. The maximum channel head drainage area produced a channel network that was closer to the observed net-work (Figure 3.18) but with an under-representation of stream channels near the ridgetops (Type II error). The drainage networks produced by median and mean (Figure 3.19) channel head drainage areas were similar to each other; they did not include some observed channels but did generate a few channels that were artifacts of the DEM network generation process and were not observed (mix of Type I and Type II errors). For sediment production calcula-tions, the drainage network generated using the maximum channel head drainage area is the most appropriate measure of stream length, as it is a conservative measure: while it excludes some observed channels with very small drainage areas, it does not include channels that do not exist.


Figure 3.17 Generated drainage network using the minimum surveyed channel head area as the start of each channel.

Figure 3.18 Generated drainage network using the maximum surveyed channel head area as the start of each channel.

Figure 3.19 Generated drainage network using the mean surveyed channel head area as the start of each channel.


Based on this drainage network, the average sediment production rate per unit length, or unit sediment production (USP), for first- and second-order channels were remarkably simi-lar: 0.00644 tons/ft/yr and 0.00617 tons/ft/yr, respectively (Table 3.8). The sediment produc-tion estimates varied considerably between different reaches, however, in part due to the wide range of bank heights, which varied from 5.5 ft in gully-like reaches to less than 0.5 ft in reaches where the transition from hillside to channel was more gradual (Tables 3.9 and 3.10). Some of the stream reaches observed had very high banks (over 5 ft), which would not have been predicted from regional curves or other regional relationships that fo-cus on the height of the active floodplain (bankfull) rather than the height of the bank, which is often at the level of a terrace.

The results of this analysis suggest that unmapped first- and second-order stream chan-nels are a significant source of sediment, contributing 1000-7000 tons/yr. This amount of sediment is the same order of magnitude as the sediment produced from blue-line streams. Because these sediment production estimates are based on the drainage network generated from the maximum channel head drainage area—and, therefore, the shortest generated length of first- and second-order channels—they are more likely to be conservative than overestimates.

Table 3.8 Unit Mass Erosion and Annual Load Summary for Unmapped Channel Reaches

Stream Order

Total Stream Length, Lr-order

(ft)

Mean Unit Mass Erosion,

mB (tons/ft/yr)

Min Unit Mass Erosion,

mB (tons/ft/yr)

Max Unit Mass Erosion,

mB (tons/yr/ft)

Mean Annual

Sediment Load

(tons/yr)

Min Annual

Sediment Load

(tons/yr)

Max Annual

Sediment Load

(tons/yr) 1 271670.0 0.00644 0.00259 0.01699 1749.3 702.5 4615.6 2 146933.3 0.00617 0.00248 0.01628 906.7 364.1 2392.4

Table 3.9 Unit Mass Erosion: First-Order Unmapped Channel Reaches

Reach ID

Bank Length, Le

(ft) Stream Order

Eroding Bank Length, E

(%)

Bank Height, H

(ft)

Erosion Rate, ehw

(ft/yr)


GCT3 31 1 50 2.5 0.249 0.00881 GCT3 107 1 80 1.5 0.249 0.00846 GCT3 161 1 30 0.8 0.249 0.00169 GCT3 135 1 0 0.5 0.249 0.00000 GCT3 91 1 30 0.8 0.249 0.00169 GCT3 68 1 80 1.5 0.249 0.00846 GCT3 60 1 50 2.5 0.249 0.00881 GCT3 123 1 40 1.5 0.249 0.00423 GCT3 159 1 80 1.2 0.249 0.00677 GCT3 116 1 40 0.8 0.249 0.00226 GCT4 76 1 30 1.1 0.249 0.00233 GCT4 79 1 40 0.8 0.249 0.00226 GCT4 49 1 10 1.2 0.249 0.00085 (Cont’d)


Reach ID

Bank Length, Le

(ft) Stream Order


(%)

Bank Height, H

(ft)

Erosion Rate, ehw

(ft/yr)


(Cont’d) GCT4 54 1 30 1.2 0.249 0.00254 GCT4 78 1 50 1.2 0.249 0.00423 GCT4 56 1 20 0.8 0.249 0.00113 GCT4 34 1 40 0.5 0.249 0.00141 GCT4 38 1 20 1.5 0.249 0.00212 GCT4 43 1 0 1.5 0.249 0.00000 GCT4 57 1 40 1.5 0.249 0.00423 GCT4 83 1 30 2 0.249 0.00423 GCT4 42 1 20 1.2 0.249 0.00169 GCT4 98 1 10 0.4 0.249 0.00028 GCT4 156 1 25 0.6 0.249 0.00106 GCT4 115 1 25 0.6 0.249 0.00106 BBT3 2 1 50 2.4 0.249 0.00846 BBT3 26 1 50 2.4 0.249 0.00846 BBT3 40 1 50 2.4 0.249 0.00846 BBT3 76 1 50 2.4 0.249 0.00846 BBT3 89 1 40 2.4 0.249 0.00677 BBT3 29 1 35 1.1 0.249 0.00271 WB2 5 1 50 4.5 0.249 0.01587 WB2 5 1 80 4.5 0.249 0.02538 WB2 12 1 80 4.5 0.249 0.02538 WB2 35 1 80 4.5 0.249 0.02538 WB2 23 1 50 4.5 0.249 0.01587 Total 2451

Table 3.10 Unit Mass Erosion: Second-Order Unmapped Channel Reaches

Reach ID

Bank Length, Le

(ft) Stream Order


(%)

Bank Height, H

(ft)

Erosion Rate, ehw

(ft/yr)


GCT4 32 2 30 1 0.249 0.00212 GCT4 40 2 30 1.2 0.249 0.00254 GCT4 34 2 50 1.4 0.249 0.00494 GCT4 58 2 40 0.4 0.249 0.00113 GCT4 31 2 40 0.8 0.249 0.00226 GCT4 101 2 50 1.1 0.249 0.00388 GCT4 108 2 40 1.8 0.249 0.00508 GCT4 43 2 30 2.4 0.249 0.00508 GCT4 46 2 40 2.4 0.249 0.00677 GCT4 54 2 50 1.5 0.249 0.00529 GCT4 93 2 10 1.5 0.249 0.00106 (Cont’d)


Reach ID

Bank Length, Le

(ft) Stream Order


(%)

Bank Height, H

(ft)

Erosion Rate, ehw

(ft/yr)


(Cont’d) GCT4 61 2 40 1.3 0.249 0.00367 GCT4 39 2 30 1.3 0.249 0.00275 GCT4 32 2 30 1.3 0.249 0.00275 GCT4 22 2 20 1.8 0.249 0.00254 GCT4 24 2 40 3 0.249 0.00846 GCT4 30 2 40 3 0.249 0.00846 GCT4 26 2 40 3 0.249 0.00846 GCT4 2 2 30 2.4 0.249 0.00508 GCT4 13 2 30 2.4 0.249 0.00508 GCT4 21 2 30 2.4 0.249 0.00508 GCT4 20 2 30 2.4 0.249 0.00508 GCT4 19 2 30 2.4 0.249 0.00508 GCT4 21 2 30 2.4 0.249 0.00508 GCT4 20 2 30 2.4 0.249 0.00508 GCT4 9 2 30 2.4 0.249 0.00508 GCT4 16 2 30 3 0.249 0.00635 GCT4 29 2 30 3 0.249 0.00635 GCT4 26 2 40 3.5 0.249 0.00987 GCT4 42 2 40 3.5 0.249 0.00987 GCT4 108 2 20 4.5 0.249 0.00635 GCT4 101 2 50 5.5 0.249 0.01939 GCT4 89 2 20 5.5 0.249 0.00776 GCT4 102 2 50 5.5 0.249 0.01939 GCT4 92 2 50 4 0.249 0.01410 GCT4 59 2 40 2 0.249 0.00564 GCT4 18 2 30 1.8 0.249 0.00381 GCT4 19 2 30 1.8 0.249 0.00381 GCT4 6 2 30 1.5 0.249 0.00317 BBT2 20 2 50 1.3 0.249 0.00458 BBT2 35 2 80 2.2 0.249 0.01241 BBT2 92 2 40 4.5 0.249 0.01269 BBT2 85 2 40 4.5 0.249 0.01269 BBT2 22 2 30 1.5 0.249 0.00317 BBT2 549 2 20 1.5 0.249 0.00212 BBT2 555 2 30 1.5 0.249 0.00317 BBT2 12 2 50 1.8 0.249 0.00635 BBT3 11 2 30 1.2 0.249 0.00254 BBT3 29 2 50 1.4 0.249 0.00494 BBT3 27 2 40 2 0.249 0.00564 BBT3 19 2 40 2 0.249 0.00564 (Cont’d)


Reach ID

Bank Length, Le

(ft) Stream Order


(%)

Bank Height, H

(ft)

Erosion Rate, ehw

(ft/yr)


(Cont’d) BBT3 44 2 40 2 0.249 0.00564 BBT3 53 2 40 3.5 0.249 0.00987 BBT3 31 2 30 3 0.249 0.00635 BBT3 47 2 20 3 0.249 0.00423 BBT3 34 2 50 2.8 0.249 0.00987 Total 3371

Upland Erosion

Pond Results The influence of climate and soils were nearly uniform throughout the watershed. The

influence of land use was slightly less uniform: ponds that were in areas with grazing had significantly higher volumes of sediment deposition than those ponds with limited or no grazing (Table 3.11). In general, the pond data indicated that rates of sediment production were relatively high for a primarily forested watershed, typically more than 4 tons/ha/yr. The USDA National Resources Inventory (2007) lists the average sheet and rill erosion in Ken-tucky as 10.1 tons/hectare/yr for cultivated crops and 2.5 for noncultivated crops. Typical acceptable soil loss tolerance values, or T-values, established by the US Department of Ag-riculture range from about 5 to 12 tons/hectare/yr.

GeoWEPP Results Overall, the GeoWEPP model performed well, with predicted sediment mass being the

same order of magnitude as that measured in the pond surveys (Table 3.12 and Figure 3.20). An ordinary least squares regression of the pond survey data versus GeoWEPP output al-most exactly matches the line demonstrating perfect agreement (Figure 3.21), indicating that the model did not consistently over- or under-predict. Although erosion rates estimated in the model may have errors, no evidence was found of systematic bias that might indicate whether sediment mass estimates were too high or low.

The highest rate of sediment production from upland erosion was from Ballard Branch, which was greater than would be expected from a subwatershed with very little agriculture. The lowest rates came from the eastern tributaries (GCT1 and GCT2), where the underlying geology comprises karst-prone strata that reduce the quantity, frequency, and duration of surface runoff.


Table 3.11 Upland Sediment Production Rates Estimated from Pond Sediments

Pond Name

Deposition Period (yrs)

Drainage Area (ha) Land Use

Sediment Production Rate, Sd

(tons/ha/yr) Crawford 57 3.4 Never grazed, hay pasture 1.43 Gunn 25 3.8 Limited grazing in past 3.20 Hickory Grove Rd 45 2.3 Grazing 7.65 McDevitt 49 2.0 Limited grazing 2.51 Perry 1 15 16.2 Grazing on lower 25% 5.36 Perry 2 77 0.7 Limited grazing in past 2.33 Sullivan 39 1.6 High amount of grazing 6.27 Wilson 1 27 3.8 Some construction 5.25 Wilson 2 20 2.2 No grazing 1.68

Table 3.12 Upland Sediment Production Rates Estimated from GeoWEPP

Subwatersheds Drainage Area (ha)

Sediment Mass Produced, Mup

(tons/yr)

Sediment Production Rate, Sm

(tons/ha/yr) Ballard 906.8 8441 9.2 GCT1 138.29 583 4.2 GCT2 359.25 1899 5.3 GCT3 122.17 831 6.7 Goose I-64 542.43 3415 6.2 Watts 294.72 1770 5.9 Total 2363.66 16,939 7.1

Figure 3.20 Sediment yields (tons/ha/yr) modeled using GeoWEPP for individual hillsides in the Goose Creek watershed. Grayscale areas were not modeled.


Figure 3.21 The upland erosion rate estimated from the pond surveys compared to the sediment yield predicted for the same hillslope using GeoWEPP. An ordinary least squares regression is very similar to the line of perfect agreement (x = y), suggesting a lack of bias in the results.

Floodplain Sediment Storage The major influences of sediment deposition appeared to be the presence of downstream

flow obstruction, such as a narrow bridge, culvert or other structure; the valley slope (steep-er valleys showed fewer signs of deposition); and channel entrenchment (entrenched streams accessed the floodplain infrequently and had lower deposition rates than unentrenched streams). Measured deposition rates ranged from 1.2 to 224 tons/ha/yr (Table 3.13), with generally much lower rates on floodplain terraces than on active floodplains near the chan-nel. The highest reading came from a mat installed on a low bench upstream of an obstruc-tion that caused backwater during high flows. These rates are relatively high compared to rates reported in Maryland, which ranged from 1.65 to 17.1 tons/ha/yr (Gellis et al. 2009). This discrepancy may not be as extreme as it appears, however; it may be due in part to the difference in measurement locations: the measurements in Goose Creek were from active or actively forming floodplains and the floodplain terrace, whereas the Maryland study meas-urements were only from the floodplain terrace.

Total sediment deposition, Mdep, on floodplains and terraces in Goose Creek watershed was estimated at 1537 tons over a one-year period. The accuracy of this estimate is uncertain due to the wide area over which deposition can occur and because the deposition may vary locally more than is represented by the deposition classes (Table 2.15) used in this study. Nevertheless, the sediment storage is of the same order of magnitude as the sediment pro-duction from bank erosion on blue-line streams.

y = 0.9454xR² = 0.4424

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10

Geo

WEP

P es

timat

ed y

ield

(ton

s/ha

/yr)

Observed pond sediment production (tons/ha/yr)

1:1


Table 3.13 Sediment Deposition Rates

n = 18 Sediment Deposition Rate, D

(tons/ha/yr) Mean 43.9 Median 30.8 Min 1.2 Max 224.3 St. Dev 51.2

3.3 SUSPENDED SEDIMENT LOADS

The highest loads per unit area (tons/ha) were measured in GC3 near the confluence with Ballard Branch. The banks in GC3 are high, and evidence of a former mill pond was found. The high banks limit floodplain access, so all sediment transported to this reach, ex-cept during very large floods, is contained within the channel. Downstream of GC3, the unit sediment load was lower, presumably because tributaries with lower sediment loads conflu-ence with the main stem.

In general, the average annual SSC at a site increased with stage. This is a broad gener-alization, however, as many recorded SSCs did not follow that trend, and the minimum and maximum annual SSCs at each site did not consistently increase with stage (Table 3.14). For the majority of sites, no single relationship between stage and SSC represented the diversity of all SSC values that were recorded; the relationships varied depending on which SSC

Table 3.14 Suspended Sediment Concentrations from US U-59 Samplers Reach

ID Annual Statistic

Bottle 1 (mg/l)

Bottle 2 (mg/l)

Bottle 3 (mg/l)

Bottle 4 (mg/l)

Bottle 5 (mg/l)

GCT2 Goose Trib Min 300.8 465.9 311.8 847.4 2389.5 Max 4030.8 3043.0 2344.0 2237.6 15474.0 Average 1529.3 1261.2 1487.2 1654.9 8287.2 Std Dev 1205.2 843.8 805.4 552.2 6636.8 BB1 Ballard Br Min 275.8 146.8 277.7 474.8 1414.5 Max 1142.6 13786.3 9965.1 4888.9 5357.7 Average 598.8 3938.9 2143.3 2090.7 2874.6 Std Dev 269.1 4733.5 2838.3 1731.2 1715.2 GC3 Goose I-64 Min 327.5 474.4 631.5 706.1 2584.2 Max 1441.1 1303.4 1124.7 2747.3 4058.8 Average 875.0 856.1 941.2 1863.7 3321.5 Std Dev 385.7 281.8 194.4 967.8 1042.7 GC2 Goose Cave Min 234.0 273.4 567.7 759.5 2175.9 Max 2661.6 2141.7 2281.0 5511.3 5179.1 Average 880.2 773.0 999.3 3042.4 3874.8 Std Dev 838.6 503.1 543.0 2296.8 1540.0 GC1 Crab Orchard Min 24.2 283.0 339.4 393.5 567.7 Max 3401.9 1778.0 2259.3 12450.8 2138.9 Average 1067.0 796.7 1059.2 4115.0 1423.1 Std Dev 908.0 465.3 773.1 4334.9 696.8


values were included in the regression. Typically, plotting stage as a function of the mini-mum SSC values provided a monotonically increasing relationship between stage and SSC, indicating that fine sediment was in transport at all flows. Conversely, the maximum values showed considerable scatter and no discernible trend (e.g., Figure 3.22), indicating that sup-ply of sediment was highly variable during floods. Similarly, plots of all data for a single site also showed considerable scatter and produced relationships that were incorrect (e.g., the regression would predict decreasing SSC with increasing stage). Because stage data were used to estimate discharge, this lack of consistent relationship between stage and all SSC values translated into a lack of relationship between discharge and SSC.

Even when all sites were plotted together for a larger sample population, no single rela-tionship between discharge and SSC represented the diversity of SSC values that were re-corded (Figure 3.23). Another problem with using the entire dataset to develop a rating curve was that the regression frequently predicted very high SSC for stages beyond the cali-bration data, whereas the minimum SSC value regression curves produced more modest in-creases with discharge.

Suspended sediment loads estimated for the sites in this project (Tables 3.15 and 3.16) using only the minimum SSC values are much lower than would have been estimated using a regression from all SSC values. The use of the lower bound of suspended sediment con-centration may account for much of the approximately 13,000-ton difference between total measured yield and floodplain storage masses (about 8000 tons) and production masses (about 21,000 tons) within the watershed. Use of non-lower bound estimates, however, would have produced greater yield than production. These results suggest that data derived from passive suspended sediment samplers has a high uncertainty and a potentially high de-gree of error and is inadequate to accurately estimate sediment loads in Goose Creek water-shed. Therefore, the data in Table 3.16 also has a high uncertainty. The uncertainty for thesediment production is estimated as 50-200 percent, primarily based on the representative

Figure 3.22 Relationship between suspended sediment concentration and stage for sites in Goose Creek watershed.

0

1

2

3

4

5

6

7

8

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

Stag

e (ft

)

SSC (mg/L)

MinMedianMaxAll Data


Figure 3.23 Relationship between suspended sediment concentration and discharge for sites in Goose Creek watershed. Flows at Goose Cave were too high for grab samples to be collected.

Table 3.15 Estimated Event and Annual Suspended Sediment Loads

Suspended Sediment Load (tons) Annual Load Unit

Sediment Load Drainage 2007 2008 (tons) (tons/ha)

Reach ID

Area (mi2)

14-Feb

26-Feb

8-Mar

4-Apr

17-Apr

26-Oct

17-Jan

5-Feb

6-Mar

21-Mar

Feb-Feb

Mar-Mar

Feb-Feb

Mar-Mar

GCT2 1.5 N/A 32 146 21 3 10 55 12 24 4 278 305 0.72 0.79 BB1 3.6 154 49 112 10 11 14 403 59 1230 109 812 2151 0.87 2.31 GC3 6 146 227 830 214 49 186 2865 291 1197 209 4807 6212 3.09 4 GC2 8.1 0 438 574 432 152 822 1274 1006 773 53 4698 5085 2.24 2.42 GC1 10.3 152 10 247 270 384 149 3483 70 4283 81 4764 9128 1.79 3.42

Table 3.16 Summary of Annual Sediment Production, Storage, and Yield Masses in Goose Creek Watershed Estimated Annual Sediment Mass (tons)

Watershed Subwatershed

Components of Sediment Delivery System Goose Cr

Watershed Ballard Branch

Goose Cr (mile 1.85

to 4.2) Watts

Branch

Goose Cr (mile 0.0 to 1.8)†

Production Upland erosion 16,939 8441 3415 1770 3313 Channel bank erosion, unmapped channels 2656 948 549 328 831 Channel bank erosion, blue-line channels 1255 651 188 67 349

Storage Floodplain storage 1360 181 522 38 796 In-channel storage Not measured

Transport Annual suspended sediment yield: load at mouth of watershed or subwatershed

6950* 1482 4028 N/A N/A

* Average of GC1 Feb-Feb and Mar-Mar periods. † Excluding the Watts Branch subwatershed.

0

2000

4000

6000

8000

10000

12000

14000

16000

0 500 1000 1500 2000 2500 3000

SSC

(mg/

L)

Discharge (cfs)

Goose Cave bottlesGoose I64 bottlesGoose I64 grab samplesCrab Orchard bottlesCrab Orchard grab samplesGoose trib bottlesGoose trib grab samplesBallard bottlesBallard grab samples


ness of sample data errors compared to the overall population. The uncertainty of the load estimates was not calculated because no data was available for the falling limb of flood events. Therefore, the discrepancy between sampled events and the complete hydrological time series is unknown.

No storm events were captured in the summer during the sampling program. While this may have been due to an undetected malfunction in the monitoring equipment, precipitation was low for the period, and the suspended sediment load would have been very minor. The majority of suspended sediment was transported during the winter months. The streams ap-peared most turbid following a series of freezing and thawing events, which loosened high quantities of sediment on eroding banks. The highest SSC values were measured following freeze-thaw, although some of these data were not included in load estimations because freezing of the sample bottles often caused suspected contamination.

The data collected from Goose Creek watershed are typical of those from small streams in that variation is high both within a single flood event and between successive events. A measurement method that used continuous data rather than discrete bottle samples would improve the accuracy of sediment load estimations by capturing the variability of SSC on the rising and falling stage.

3.4 ASSIMILATIVE CAPACITY

The assimilative capacity of the watershed—in this case, the fine sediment mass that can be stored on riffles in each subwatershed without embedding them by more than 50 percent (Table 3.17)—is an order of magnitude lower than bank erosion from both blue line streams and unmapped channels, and is two orders of magnitude lower than the sedi-ment mass produced through upland erosion and the sediment loads. Detailed information regarding the mass of sediment required to embed riffles and the characteristics of that sed-iment (grain size, density, organic content, etc.) is extremely limited, so comparisons with published data are not possible. However, based on errors of estimates of riffle widths, lengths, sediment characteristics, and frequency, the error of these estimates is estimated to be 50-300 percent. Even at the upper limit of this error estimate the mass of sediment neces-sary to embed riffles is much smaller than the annual sediment production within Goose Creek watershed.

These calculated masses represent the amount of fine material that may be stored on rif-fles at any one time. Unlike other pollutants, however, this assimilative capacity of the wa-tershed cannot be expressed as a load or meaningfully related to existing loads. At present, no methods provide a means to relate this mass to a load because the proportion of the load that is deposited on the riffle is not fixed but instead varies between riffles and is strongly dependent on multiple variables, including the timing of sediment supply, the proximity of the sediment source to the riffle, the magnitude of the flow, and the morphology of the

Table 3.17 Estimated Sediment Mass Required to Embed Riffles by 50 Percent Estimated Sediment Mass (tons)

Watershed Subwatershed

Goose Cr

Watershed Ballard Branch

Goose Cr (mile 1.85

to 4.2) Watts

Branch

Goose Cr (mile 0.0 to 1.8)*

Sediment deposited on riffles 193 91 31 12 71 * Excluding the Watts Branch subwatershed.


channel. Sediment supplied locally and delivered to and deposited on a nearby riffle during base-flow periods may be removed by floods. Likewise, sediment supplied from either local or distal sources that is delivered to a riffle during the rising stages of a flood may be trans-ported downstream instead of being deposited, while the same load of sediment transported over a riffle during the receding stages of a flood may accumulate on the riffle. Moreover, because local conditions so strongly influence the development of embeddedness in these watersheds, the load that embeds a riffle will be highly variable at any given point in the wa-tershed and cannot be accurately described as a maximum allowable mass load per unit time. Instead, an alternative measure for a Goose Creek watershed TMDL is necessary (USEPA 1999, p. 2-4).

4. Conclusion 4.1 SOURCES, EMBEDDEDNESS, AND WATER QUALITY GOALS

Two conditions must be met for fine-grained material to embed a riffle substrate: an ad-equate supply of fine sediment must be conveyed by the flow, and local stress conditions must exist to allow deposition of fine-grained material. These conditions are met and sub-stantial areas of riffle embeddedness occur in three types of locations in Goose Creek water-shed (Location Types 1-3):

1. Immediately downstream of an eroding hillslope or high, weathering streambank: a surficial crust of bank material loosened by weathering detaches and falls to the base of the streambank, washes to the base of the bank or into the channel by rain-fall, or, in the lowest portion of the bank, washes directly into the water by wave action or minor increases in flow and stage. The fine sediments derived from weathered bank material are deposited in the channel when flow velocities are low, typically following periods of little or no precipitation. Low flow in the channel is capable of transporting the fine sediments only a short distance, and some of the sediments are deposited along the edge of the water and in other very low-velocity areas of downstream riffles. If weathering and transport of the fine material persists without a large flood to remove sediment, then accumulation may cover a substan-tial portion of the riffle or even the entire substrate. Algae, aquatic vegetation, and herbaceous vegetation growing in and along a riffle (Figure 4.1) can enhance ac-cumulation of sediment (Thorton et al. 1997).

2. Immediately downstream of the confluence of a tributary channel with another much larger channel: when rainfall produces runoff in a small tributary, it delivers fine sediment to confluences with downstream larger channels. When flow velocity and depth in the larger channel downstream of the confluence does not respond significantly to the rainfall event either because of the longer response time of the larger channel’s watershed or because of non-uniform rainfall, the larger channel may not have sufficient flow to transport the fine sediment supplied by the tribu-tary. The sediment therefore deposits near the confluence and in downstream rif-fles. Deposits in channels were particularly pronounced downstream of conflu-ences of small tributaries with bare, weathering banks where large volumes of sediment accumulated following freeze-thaw cycles and then were transported into the larger downstream channels during subsequent small storm events (Figure 4.2) (Croasdaile and Parola 2011).


Figure 4.1 Deposition of fine sediment permits in-channel vegetation growth that promotes further trapping of fine sediment.

Figure 4.2 This small tributary supplies sediment to Goose Creek downstream of Ballard Branch confluence following small storms when the velocities in the main stem are low enough for sediment to deposit on riffles.

Conclusion 69

3. Upstream of channel obstructions or contractions that promote sediment deposition by creating backwater during floods, when sediments from both local and distal sources are transported: channel morphological features such as bends with a small radius of curvature, channel boundary contractions, or large woody debris jams (Figure 4.3); and structures such as culverts, weirs, or bridges. Channel obstruc-tions can reduce velocities sufficiently for some fine sediment to deposit (Gurnell and Sweet 1998). These locations are effective at storing sediment and reducing loads to downstream reaches.

In any of these situations, the proportion of the load that is deposited on the riffle is not fixed but instead varies between riffles and is strongly dependent on multiple variables. Dur-ing base flow periods, supplied sediment is transported only a short distance downstream, and load measurements in any given channel will vary depending on proximity to local sed-iment sources; immediately downstream of a low- and/or base flow deposition area, the measured load would be negligible. During floods, when sediment is transported from local and distal sources to those same locations, the flow conditions may be sufficient to mobilize fine sediment from the bed and ensure that embeddedness does not persist in those riffles. Thus, the riffles could be intermittently impaired and unimpaired by embedded sediments. In areas of the channel that are backwatered during floods, however, when sediment from upland sources constitutes much of the load, as little as 0.5 tons of sediment would be suffi-cient to embed a single riffle. The persistence of embeddedness in these locations would de-pend on the stability and permanence of a backwater-inducing feature, and sediment sup-plies would have to be virtually eliminated throughout the watershed in order to reduce flood loads sufficiently to prevent embeddedness in backwater locations. These locations provide habitat and are effective at storing sediment and reducing loads to downstream reaches, however, and in many cases function as grade control.

Figure 4.3 Debris jams (either formed accidentally or by beavers) cause reduced flow velocities upstream of the obstruction and can cause temporary embeddedness of riffles and filling of pools.


Because local conditions and multiple variables so strongly influence the development of embeddedness in these watersheds, the load that embeds a riffle will be highly variable at any given point in the watershed, and no methods currently exist to accurately describe it as a maximum allowable mass load per unit time. Instead, an alternative measure for a Goose Creek watershed TMDL is necessary (USEPA 1999, p. 2-4). Channel morphological indica-tors such as bank heights or embeddedness or hydrologic indicators such as frequency of floodplain inundation would be more useful than total daily sediment loads as water quality goals for reducing sediment impairment in Goose Creek watershed. BMP strategies based on these indicators would need to be local or reach-scale and should focus on reducing sedi-ment supply during base-flow periods. While the BMPs would be unlikely to affect embed-dedness in other reaches, they would be a feasible, sustainable means of reducing impair-ment in reaches where they were implemented, even though their effectiveness could not be measured or described in terms of a reduction in a watershed daily or annual load.

4.2 MANAGEMENT STRATEGY RECOMMENDATIONS

Management strategies to reduce embeddedness should focus first on reducing local sediment supplies and, where possible, increasing sediment storage on floodplains. In some cases, delivery of upland sediments to the channel network could also be reduced as part of the implementation project. For each of the Type 1 or 2 locations where impairment reduc-tion is feasible, the most effective BMP would be stream restoration that increases the fre-quency of floodplain inundation. In Type 3 locations, the feasibility of reducing embed-dedness will depend on the feature causing backwater. In some cases, stream and floodplain restoration would be effective at reducing the impairment. In other cases, such as those with culverts or other structures, the backwater area might serve best as long-term deposition and storage areas that help to reduce downstream embeddedness. The sediment trapping effi-ciency of these areas could be further increased by reducing floodplain elevations and creat-ing wetland depressions. Temporary structures such as debris jams could be evaluated to de-termine whether channel and valley configuration were conducive to blockage formation. If they were, the jam could be augmented, floodplain elevations reduced, and the area utilized for sediment storage.

Reducing Local Sediment Supply from Bank Erosion

The development of riffle embeddedness in Type 1 or 2 locations could be reduced through stream and floodplain restoration. Reducing bank heights and, where valleys are wide enough to provide a floodplain, relocating the channel away from the hillside would reduce the local sediment supply to negligible amounts during flow conditions—typically base and low flow—that would permit deposition in the channel. In Type 3 locations, reduc-ing bank heights would allow flood flows to be distributed to and across the floodplain and reduce the likelihood of backwater. This would be feasible in most locations other than those where removal or replacement of a large structure would be required.

The cost of stream restoration projects are typically estimated on a per linear foot basis. Costs are estimated at between $100 and $300 per linear foot, based on the watershed size, for reconstruction of the channel, and $3 to $10 per cubic yard for excavation of floodplain soils to lower the floodplain. The large variation in excavation cost is directly related to the excavation methods and transport costs. Typically, restorations range from $150 to $300 per linear foot of restored channel, including the cost of excavation of the floodplain. The length

Conclusion 71

of a stream restoration project in residential and agricultural valleys would be largely de-pendent on the availability of willing landowners; one option for increasing their incentive to participate would be the use of excavated materials to enhance the value of valley-bottom land outside the riparian zone.

Increasing Sediment Storage on Floodplains

Where valleys are wide enough to provide a floodplain, stream and floodplain restora-tion could re-create natural sediment-trapping features such as alluvial fans and floodplain wetlands and isolate man-made storage zones that have been remobilized, such as old sedi-ment ponds. Stream restoration projects that lowered the floodplain significantly could, all other factors being equal, increase sediment deposition by an order of magnitude, which would be on par with the sediment currently being produced through upland erosion and bank erosion.

Reducing Local Sediment Supply of Eroded Upland Soils: Gully Stabilization

Where stream and floodplain restorations are implemented in reaches in the uppermost areas of the blue-line channel network, the local supply from eroded upland soils could be reduced by gully control measures in unmapped tributaries (i.e., reaches with drainage areas of less than about 4 hectares). The USDA-NRCS provides technical guidance on the selec-tion and installation of various methods of controlling and treating gully erosion (USDA 2007), and we recommend contacting the NRCS for technical guidance. The treatment op-tions most applicable to Goose Creek watershed for load reduction would probably be gully plugs, debris jams, or check dams. These barriers would not only trap sediments but would also slow the downslope movement of water, which could lower the rate of bank erosion in the gullies. Construction of dams or gully plugs can be a simple process requiring a limited amount of materials: typically, locally sourced rocks, woody debris and soil. Check dams could be constructed alone or in conjunction with permeable reactive barriers (PRBs) stacked in pyramid form. PRBs are constructed of porous media bags filled with crushed stone, which filters nutrients or contaminants from the water leaching through the bags (USEPA 1998). Costs to construct a small check dam or gully plug will primarily depend on material, labor, and equipment costs. On-site trees and rock may be suitable for use. In most cases, however, some aggregate will have to be purchased; the typical cost of large aggre-gate 6-12 inches in diameter is about $30 to $50 per ton delivered, depending on transport costs. Equipment costs will typically be greater than the cost of materials unless the land-owner provides a backhoe. Equipment rental rates vary widely depending on the unit’s loca-tion and size. An hourly rate for a backhoe with operator would be about $80/hr ($3200/wk); a trackhoe for larger projects would cost approximately $150/hr ($6000/wk). Total cost for installing gully plugs or small checks dams could be on the order of $4000-$20,000 per gul-ly.

4.3 IMPAIRMENT REDUCTION ESTIMATES

Ten blue-line channel reaches were identified as particularly suitable for implementa-tion of these BMP strategies to reduce embeddedness in Goose Creek watershed (Table 4.1 and Figure 4.4). Each of these reaches has substantial areas of riffle embeddedness, identifi-able local sources of sediment, and valleys with no major roadways or development. The exception is reach GC2, which had a predominantly planar bedrock channel bed with only


Table 4.1 Embedded Riffles in Goose Creek Watershed and Estimated Impairment Reductions Due to BMP Implementation 2008 Post-BMP Impairment

Percent Embeddedness Percent Embeddedness Reduction*† 0-25 25-50 50-75 75-100 0-25 25-50 50-75 75-100 Riffle Percent of

Reach ID Riffle Count Riffle Count Count Watershed GC2 1 2 1 0 2 2 0 0 1 1 GC5 0 2 4 0 3 3 0 0 4 3 GCT2B/C 0 2 12 0 7 7 0 0 12 10 GCT3 DS 0 2 2 4 4 4 0 0 6 5 GCT3 US 0 0 7 1 4 4 0 0 8 7 GCT4 0 1 7 3 5-6 5-6 0 0 10 8 BB5 0 2 14 1 8-9 8-9 0 0 15 13 BBT3 - DS 1 2 1 3 3-4 3-4 0 0 4 3 BBT3 - US 0 4 10 3 8-9 8-9 0 0 13 11 BBT6 0 4 2 5 5-6 5-6 0 0 7 6 Other reaches 6 72 26 14 5 72 27 14 0 0 Total 8 93 86 34 54-59 121-126 27 14 80 67 * Assumes riffles that are less than 50 percent embedded are unimpaired (RBP optimal and suboptimal categories). † These are conservative estimates based on the assumption that BMP implementation would not increase the total number of riffles in the wa-

tershed. While distance between riffles was relatively short in many reaches, the distance would likely be reduced in a restoration, and the total number of riffles in the reach, and thus the watershed, would increase.

Figure 4.4 Blue-line channel reaches identified as particularly suitable for implementation of BMP strategies to reduce embeddedness in Goose Creek watershed.

Conclusion 73

four short riffles along a 1600-ft reach. Increasing non-embedded riffle habitat in this reach would best be achieved by increasing the overall amount of riffle habitat. Following BMP implementation in a reach, a majority of its riffles would be less than 50 percent embedded, which would correspond to a score of optimal or suboptimal for the RBP embeddedness pa-rameter.

The estimates of impairment reductions are based only on the data collected for this project. The sedimentation processes contributing to the impairment were highly variable, and the uncertainty of the estimates is undetermined. They should be considered to be pre-liminary and may need to be modified as more data becomes available. Therefore, BMP im-plementations and revisions of estimates and strategies should be iterative processes. Fol-lowing implementation of a BMP on a small scale, monitoring data should be collected to verify its effectiveness in reducing embeddedness and to confirm that the relationships be-tween sources, embeddedness, and water quality targets were accurately identified. Two possible factors that could influence the long-term viability of the BMPs are future changes in land use—either development or direct modifications to the stream or valley—and rates of floodplain sediment deposition. The long-term sustainability is currently unknown for sediment storage on floodplains that are lowered substantially through restoration. Deposi-tion rates in Goose Creek were as high as 2-5 mm/yr on low active floodplains during this project’s monitoring period; at that rate, floodplain deposition and storage could continue for at least 50 years or maybe much longer.

Because implementation is equally viable in each reach, three additional factors may be useful in decisions about which of these should be selected for implementation as a pilot project:

1. Potential increase in proportion of unimpaired habitat: Because the embedded rif-fles in some reaches account for more than 10 percent of the watershed’s sedi-ment-impaired riffle habitat, BMP implementation in a single reach could signif-icantly increase the proportion of unembedded riffles in the watershed.

2. Potential for optimizing costs and benefits by combining BMP strategies. BBT3 or GCT4 subwatersheds (see Appendix C) would be particularly suitable as pilot sites because they have a dense network of unmapped channels with high banks. Each of the BMPs, including gully stabilization, could be implemented, which would provide the additional benefit of reducing sediment loads in reaches downstream of the BMP reach without increasing per-foot implementation costs.

3. Locations of willing landowners. Impairments were widely distributed through-out Goose Creek. If multiple adjacent landowners would be willing partners, BMPs could be implemented at a larger scale for greater impairment reduction.

4.4 STRATEGIES FOR REDUCING GOOSE CREEK SEDIMENT YIELDS

Prior to settlement, Goose Creek and its tributaries probably would have carried minor amounts of fine sediment and little or no gravel, as did other Eastern US streams (Parola et al 2007; Walter and Merrits 2008). Modifications of the channel network and changes in land use observed in the Goose Creek watershed, however, fundamentally reorganized the sediment storage system of the watershed, as has been found in other parts of the state and US (Dietrich et al. 1982), and changed the sediment regime. Not only did clearing and culti-vation relocate fine sediments from upland surfaces to valley bottoms (Figure 4.5), but


Figure 4.5 (Top) Pre-settlement valley configuration: low banks, frequently inundated floodplain, and stable vegetated hillslopes. (Bottom) Contemporary valley configuration typical of Goose Creek has an incised channel and incised tributaries with a floodplain that is rarely inundated and hence has much lower overbank sediment deposition rates than prior to settle-ment. Stream incision cuts into high banks of post-settlement alluvium and the base of hillslopes (Source: Gutshall and Ober-holtzer 2011). channelization of much of the Goose Creek watershed led to severe channel incision throughout the watershed and siltation in multiple locations as incision, bank erosion, and upland erosion increased supplies of fine-grained sediment to the channel network. The re-location and incision of upland tributaries mobilized bed, bank and hillslope sediments, while the incision and widening of tributary and main-stem channels into valley-bottom floodplain deposits released recently accumulated silt and clay. Consequently, a high load of silt and clay are being transported into and through Goose Creek to Benson Creek and downstream rivers.

The annual suspended sediment yield from Goose Creek is estimated to be 7000 tons; most flood events transport more than 100 tons of fine sediments to Benson Creek and the Kentucky River in a few hours. This current rate of sediment delivery during floods is radi-cally accelerated compared to historic conditions, when fine sediment loads transported to the Kentucky River probably would have been orders of magnitude lower (Meade 1982; Pasternack et al. 2001). Sediment yields from Goose Creek therefore could be significant contributors to sediment impairment in its receiving watersheds, and reductions in those yields could be an important component in reducing impairments in Benson Creek or the Kentucky River. Yield reduction strategies might address multiple components of the sedi-ment delivery system. The most effective BMPs would likely be those that modify (in order of decreasing feasibility) upland sediment delivery, floodplain storage, and channel erosion.

Conclusion 75

Although reducing upland erosion would also be possible, it would be less practicable in this watershed than the other strategies. Moreover, without additional sediment retention on floodplains and in channels, even if the entire watershed were forested, the output would still cause local embeddedness, and the sediment production from upland surface erosion would only be reduced by around 3000 tons per year, or less than 20 percent of an estimated 16,939 tons (Table 3.16).

Reducing Sediment Supply of Eroded Upland Soils: Gully Stabilization

Eroded upland surface soils account for the greatest component of sediment loads in Goose Creek watershed. This component could be reduced throughout the watershed by preventing the eroded soils from entering the small headwater channels and gullies at the upper extents of the drainage network. Effective BMP methods for unmapped tributaries draining less than 4 hectares would include installing gully plugs, debris jams or check dams in gullies (see Section 4.2 for a description of methods and costs). Based on the distribution of upland soil erosion rates (Figure 3.20), this BMP would be effective in any of the subwa-tersheds in Goose Creek except GCT1 (lower upland erosion rates), BBT4 (large pond), and BBT6 (large pond). The load reduction would be directly proportional to the number of headwater channels that were converted from conduits to storage zones.

Increasing Sediment Storage on Floodplains

Even though the second-largest supply of sediment was produced by bank erosion on unmapped channels, those small channels comprise about 90 percent of the watershed chan-nel network, and a prohibitively large number of linear feet would be have to be modified to reduce this component of the sediment load. Increasing storage of sediment on the flood-plains of third- and higher-order streams, which account for about 10 percent of the channel network, would be a more cost-effective BMP than reducing bank erosion in the unmapped channels (see Section 4.2). A restored reach with a length of 3000 ft that increased sediment deposition rates from those currently measured for the terrace (1.2 tons/ha/yr) to the mean measured deposition rates for all surfaces (43.9 tons/ha/yr) could decrease sediment loads to downstream waters by approximately 238 tons/yr. This estimate of load reduction is based on sediment deposition alone and would be higher if it included the other benefits of stream restoration, such as reduced sediment production from bank erosion. The unit sediment load from Ballard Branch was much lower than that measured along the main stem of Goose Creek. Therefore, stream restoration activities implemented in the reaches of Goose Creek upstream of its confluence with Ballard Branch could reduce the total sediment load more than restorations downstream of their confluence. Depending on the site, a main stem stream restoration could be combined with gully plugs in the small headwater tributaries to further increase the potential effectiveness of the BMPs.

Reducing Sediment Supply from Bank Erosion

Reducing the amount of bank erosion in a reach would involve either stabilizing the ex-isting banks or implementing a stream and floodplain restoration to reconfigure the bank profile to a more stable slope and/or reduce the height of the banks. Bank stabilization can be effective in stabilizing banks if the cause of the erosion is limited to the area being stabi-lized. Stabilization methods typically focus on armoring banks with rock or planting ero-sion-resistant vegetation to increase the capacity of the banks to resist stresses from flows.


In-channel structures such as vanes and barbs may also be used in combination with bank armoring to reduce near-bank stress. Where bank erosion is extensive, however, bank stabi-lization may not address the underlying causes of bank erosion (Riley 1998) and will likely be a short-term remedy that will require maintenance. In these cases, stream and floodplain restoration that addresses the underlying causes of bank erosion would be a more effective approach to reducing sediment production from bank erosion. Well-designed stream restora-tions not only address the local capacity of the bank to resist erosion and the local flow pat-terns causing erosion but also address the interaction (or lack of interaction) of the channel and floodplain, which is often an underlying cause of extensive bank erosion. Most design approaches for entrenched channels seek to reduce the entrenchment (Rosgen 2006) by re-ducing bank heights, although the extent to which the bank heights are reduced will depend on the overall design objectives and methods.

Sediment production due to bank erosion (i.e., unit mass erosion) on blue-line stream reaches varied from 0.003 tons/ft/yr to 0.036 tons/ft/yr. A bank stabilization or stream resto-ration project that reduced the highest measured sediment production from bank erosion by 50 percent over 2140 ft would reduce the sediment load to downstream waters by 38.5 tons/yr. Reducing sediment production from bank erosion to the lowest measured exist-ing rate over that same length would reduce sediment loads by 70.6 tons/yr. (For cost esti-mates, see Section 4.2.)

Reducing Upland Erosion Rates

The vast majority of Goose Creek watershed is composed of ridgetops and hillslopes, with narrow floodplains making up a small portion of the overall area. Although upland sur-face erosion accounts for the greatest component of the sediment production in Goose Creek watershed, achievable load reductions from this component are limited. The highest rates of sediment production due to surface erosion occurred on steep slopes that had agricultural (pasture/hay) land use. Only a very small amount of land within Goose Creek watershed, however, matched both of those criteria. Most steep slopes were forested, and most agricul-ture occurred on ridgetops or in the valley bottom. In forested areas that make up the most land area in the watershed, the rate of soil loss is already as low as can be expected for this region of highly erodible soils (USDA1980).

Even though the average sediment production rate from all agricultural land in Goose Creek was 9.1 tons/ha/yr, producing a total of 5270 tons/yr, that estimated rate does not ex-ceed the acceptable soil loss rates (T-values) set by the Department of Agriculture. Never-theless, agricultural BMPs such as development of buffer/filter strips, construction of grass waterways, restriction of livestock access to streams, management of heavy use areas, and improved grazing planning could be used to reduce the sediment production rate (KAWQA 2009). Reducing average agricultural production rates to reasonable T-values such as 4 tons/ha/yr or 6 tons/ha/yr would reduce sediment production by 2944 and 1782 tons/yr, re-spectively. Costs for agricultural BMPs vary considerably according to the type of BMP; in-stallation of grassed waterways is much more expensive than changes to cover crops. Part-ner agencies such as the NRCS already have programs to address soil loss from agricultural land, and cost-share assistance to landowners for these BMPs may be available through the USDA Conservation Provisions of the 1996 Farm Bill or the Kentucky Soil Erosion and Water Quality Cost Share Program. Of all of the potential BMP strategies for this watershed, however, reducing upland erosion rates would be the least cost-effective because upland sur-

Conclusion 77

face erosion occurs over such a wide area. Even if BMP implementation over 1 ha would re-sult in zero erosion, it would only reduce sediment loads by 4-10 tons, or by less than 0.1 percent of the total upland sediment production.

4.5 PROJECT MEASURES OF SUCCESS

Project success was to be measured according to three criteria: 1. The available protocols and GIS information for Phase 1 geomorphic assessment

in combination with Phase 2 and 3 geomorphic assessments are sufficient to clearly identify major sediment problems and provide information that allows quantification of the sediment impairments.

2. A practical watershed-based plan is developed that provides NPS strategies that are implementable and beneficial to landowners and stakeholders as well as the stream corridor ecology.

3. Sediment load and sediment deposition and its impact on the aquatic ecosystems of the watershed are reduced. Because this goal cannot be achieved until TMDLs have been developed and a watershed plan has been implemented, this criterion is to be a long-term measurement rather than being measured during the project time frame.

The project fully met the objective of identifying major sediment problems and providing in-formation to support quantification of sediment impairments. Monitoring data were suffi-cient to quantify sediment loads and identify which sources of sediment within the Goose Creek watershed were the greatest contributors to riffle embeddedness. Data collection methods were originally selected to identify areas with high loads during flood flows, based on the hypothesis that those areas would be most affected by siltation during major and/or very frequent flood events that transported the highest annual loads of fine-grained sedi-ment, and embeddedness would be correspondingly higher at the locations of the highest annual loads. Analysis of the geomorphic assessment and monitoring data, however, showed that embedded riffles were the result of both proximity to the local sediment supply and the local flow conditions at the riffle at the time the sediment was supplied. The most severely embedded riffles in non-backwater locations were those where sediment was supplied to the riffle when flow was barely above the riffle crest elevation. This was an unexpected, alt-hough not undocumented, finding (Carling and McMahon 1987). The feasibility of modify-ing those local conditions was the basis for estimating the potential for reductions in sedi-ment impairment in the watershed

The objective of developing an effective watershed management strategy to reduce sed-iment load or sediment impairment was also met. Although a full watershed implementation plan was not developed, the project did identify management strategies and specific activi-ties (BMP implementation) that would be economically and morphologically sustainable and necessary to achieve the estimated reductions in embeddedness. Potential NPS man-agement strategies such as overland erosion control, stream restoration, and bank stabiliza-tion were evaluated based on estimates of load reductions that could be expected as a result of implementation of each strategy. The technical resources necessary for implementation of each strategy were identified, and approximate costs were estimated. These estimates and recommendations will support KDOW’s development of sediment TMDLs for Benson Creek watershed.


4.6 LESSONS LEARNED AND RECOMMENDATIONS

Lesson: Continuous data are needed to accurately measure sediment loads and to link sources and loads through temporal analysis.

Passive suspended sediment samplers were used in this project to measure SSC and estimate sediment loads. The major advantage of this monitoring method is its relatively low cost. The data derived from this method, however, has a high uncertainty and represents only a small fraction of any given flood period or annual flow duration. During a flood, one to five discrete samples are collected only during the rising stage of the event. Each of those samples captures SSC at only a single point in time at one of five pre-determined stages. These samples cannot accurately document the variability of SSCs at each stage, at stages in between those that correspond to the bottle elevations, or over the entire period of the event. Moreover, because they cannot capture samples during the falling stages of the flood, proximal and distal sources cannot be differentiated through temporal analysis.

Continuously recording sensors that record surrogate parameters for SSC (e.g., turbidi-ty, laser diffraction, pressure difference, and acoustic backscatter) offer many advantages over passive samplers. These surrogate technologies are increasingly being used to improve the temporal resolution of suspended sediment sampling (Gray and Gartner 2009). Because the sensors can record measurements during rising and falling stages at intervals of seconds to hours, depending on the user preference, they reduce errors that are inherent to passive samplers and permit broader levels of analysis. Distal and proximal sediment sources can be differentiated with sensor data, for example, because sediment from distal reaches would be recorded as prolonged turbidity after a flood (Klein 1984; Williams 1989), whereas local sources would produce a short-duration peak in turbidity/TSS at the beginning of a flood (Lefrançois et al. 2007). Lesson: In streams with bank characteristics similar to those in Goose Creek watershed,

where weathering is a more significant cause of bank erosion than shear stress is, the BANCS assessment may be less useful than alternative methods of estimating erosion potential.

BEHI and NBS parameters used in the BANCS assessment method were only weakly related to measured erosion rates. The weakness of the relationship may be due in large part to subaerial weathering (freeze-thaw during the winter and desiccation during the summer) of predominantly silt and clay bank sediments. Weathering of the banks in the Goose Creek and Benson Creek watersheds appears to be an important control on bank erosion, as has been found in other watersheds (Lawler 1986; Couper and Maddock 2001; Wynn et al. 2008), and is only indirectly addressed by the bank material parameter in the BANCS meth-od. Likewise, the modified NBS parameters used in this project were not intended to ac-count for the effects of shear stress on stream banks when weathering is the primary mecha-nism of bank erosion. Neither were the NBS parameters intended to account for variations in shear stress due to changing channel morphology and locally influential features such as de-bris jams. The weakness of the relationship may also be attributed to the limited variation in bank characteristics in Goose Creek watershed. The BANCS method calls for assessment of a range of bank erosion hazard index (BEHI) and near bank stress (NBS) conditions and may be more effective in a larger watershed with a greater variety of bank characteristics. In streams with bank characteristics similar to those in Goose Creek watershed, however, re-sults from the BANCS method may be too ambiguous to be useful.

Conclusion 79

Although the BANCS parameters might be adapted to incorporate the effects of weath-ering, shear stress variations, and bank homogeneity, a simpler method might suffice for as-sessing sediment production potential from bank erosion. In banks that are eroding primarily by weathering, the erosion rate is less dependent on boundary shear stresses than banks where little or no weathering occurs. The weathering banks erode at a relatively consistent rate throughout the watershed, which may be estimated from erosion pin measurements or other assessment methods. The sediment production over a given year could then be esti-mated as the product of just three parameters: the estimated erosion rate and the lengths and heights of eroding banks. This estimate would necessarily omit the mass of sediment eroded by shear stress on non-weathering banks, but that component of the total eroded sediment mass would be negligible in channels with the same bank characteristics as those in Goose Creek watershed.

The accuracy of the estimate of annual sediment production would depend primarily on the method used to estimate the erosion rate. Most methods are unable to incorporate sea-sonal or inter-annual variability that occurs before or after the monitoring period. In very dry years, for example, desiccation and the resultant cracking due to very dry soil conditions may temporarily increase erosion rates; in wetter summers, this process of soil production may not occur. Using a longer measurement period would capture this variation but may be incompatible with time and cost constraints of an assessment project. One increasingly em-ployed method that does assimilate this variation is dendrogeomorphology (Schroder 1980; Stoffel and Bollschweiler 2009), which uses exposed tree roots to date erosion rates over the lifespan of the root (typically 5-50 yrs). This method could be utilized to estimate erosion rates in blue-line streams (Figure 4.6) and even in smaller streams and gullies (Figure 4.7).

Figure 4.6 Exposed tree roots were observed along most reaches in Goose Creek and could potentially give useful information on erosion rates averaged over a number of years, integrating the effects of years of low and high rainfall.


Figure 4.7 Exposed tree roots can provide information on erosion rates even at very small drainage areas.

Other advantages of using a dendrogeomorphic approach are that samples can be col-lected in one field visit, require no installation of equipment, and can be collected over a much greater area than typically can be assessed using bank pins.

Lesson: Drying of the channel is a common problem in Goose Creek and Benson Creek watersheds, even in reaches with large (greater than 70 mi2) drainage areas.

Most of Goose Creek dried up completely during the summer of 2008 except for isolat-ed pools with warm, stagnant water. Even in the much larger Benson Creek, reaches with flow over the riffles were rare and were typically less than 500 ft in length. The land use his-tory in Goose and Benson Creek watersheds, coupled with the limestone/shale geology, has created an incised, entrenched channel network that is poorly linked to the shallow valley aquifer and has exposed bedrock along much of its bed. The shallow bedrock and poor con-nection to the valley aquifer in Goose Creek and Benson Creek make the watersheds par-ticularly susceptible to drying following low levels of precipitation. For September 2008, when hydrologic condition was assessed, the Palmer drought severity index was −1.92, and the four-month average for June to September 2008 was −0.82. The previous year, however, was very dry: the Palmer drought severity index for 2007, averaged over the year, was 0.64. The severe drought of 2007 may have had a lagged effect in that base flows were not re-charged due to low infiltration rates.

The biological implications of this drying in Goose Creek and Benson Creek were not documented in this project, but the hydrological conditions are an important influence on aquatic community health (Boulton 2003). Given the lagged response of stream levels to precipitation (Wood 1998) and the importance of flowing water to aquatic ecosystem health,

Conclusion 81

hydrological data could provide an important context for the interpretation of biological da-ta. Drying of the channel may also have negative impacts on water quality and may reduce channel bed habitat quality, especially through siltation (Wright and Berrie 1987). BMP strategies to reduce embeddedness have the potential to also reduce the frequency and dura-tion of dry periods in Goose Creek watershed. Significant bank height reduction, for exam-ple, can affect hydrology in several ways: attenuation of flood flows to downstream reaches; increases in surface water retention, groundwater storage, and frequency of flow exchange between the channel and the aquifer; and possibly an extended duration of base flow (Parola and Hansen 2011).

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85

Appendices

87

Financial and Administrative Closeout A

1. PROJECT OUTPUTS

Milestones Expected

Begin Date Expected End Date

Actual Begin Date

Actual End Date

1. Develop and submit a QAPP to the NPS Section for approval prior to performing any water quality monitoring.

Jan 2006 Feb 2006 Oct 2007

2. Submit all draft materials to the NPS Section for review and approval prior to dissemination and use.

Jan 2006 Apr 2009 Dec 2011

3. Upon NPS Section request, submit an annual report and/or participate in the Cabinet-sponsored biennial NPS conference.

Jan 2006 Apr 2009 Dec 2011

4. Select sediment impaired watershed. Jan 2006 Mar 2006 Mar 2006 Sep 2006 5. Training for use of VTANR Phase 1 geomorphic assessment

tools. Jan 2006 Jun 2006 Mar 2006 Sep 2006

6. Conduct Phase 1 Geomorphic Assessment. Mar 2006 Aug 2006 Apr 2006 Feb 2007 7. Conduct Phase 2 Geomorphic Assessment. Aug 2006 Nov 2006 Nov 2006 Nov 2007 8. Conduct Phase 3 Geomorphic Assessment. Nov 2006 Mar 2007 Nov 2006 Apr 2009 9. Develop Watershed Management Strategies. Mar 2007 Aug 2007 Feb 2008 Apr 2011 10. Watershed Sediment and Management Strategies Report. Aug 2007 Jun 2008 Apr 2011 Dec 2011 11. Submit three hard copies and one electronic copy of the

final report, and submit three hard copies and one electronic copy of all products produced by this project to the NPS Section for review and approval.

Aug 2007 Aug 2008 Dec 2011

2. BUDGET SUMMARY

Detailed Budget

Budget Categories Section 319(h) Non-Federal

Match Total Final

Expenditures Unspent Personnel $ 238,342 $ 30,000 $ 268,342 $ 266,372.23 $ 1969.77 Supplies 6,400 0 6,400 10,054.11 (3654.11) Equipment 11,680 6,000 17,680 23,203.80 (5523.80) Travel 7,865 0 7,865 6,389.98 1475.02 Contractual 3,500 0 3,500 3500.00 Operating 70,717 71,217 141,934 141,880.86 53.14 Other $ 4,200 $ 0 $ 4,200 $ 1,817.97 $ 2382.03 Total $ 342,704 $ 107,217 $ 449,921 $ 449,718.95 $ 202.05


The University of Louisville Research Foundation was reimbursed $342,550.92. A total of $153.08 federal funds remain unspent. This project did generate overmatch of $41.38 provided by University of Louisville Research Foundation, Inc. The overmatch was not posted to the grant.

3. EQUIPMENT SUMMARY Cost Type of Equipment Units 319(h) Match Total Isco Model 6712 Full Size Portable Sampler 1 $ 0.00 $ 2,879.00 $ 2,879.00 750 area velocity probe flow module with low-

profile area velocity sensor 1 0.00 3,085.00 3,085.00

Nikon camera and accessories 1 5,282.76 0.00 5,282.76 Dry vacuum pump 1 543.18 0.00 543.18 Datalogger 1 814.82 0.00 814.82 OBS probe, cable, and datalogger 1 3,467.12 0.00 3,467.12 3001 LT Levelogger Gold, M5/F15 11 3,373.49 0.00 3,373.49 Hydrometric workstation 1 1,000.00 0.00 1,000.00 Digital gravelometer 1 1,080.00 0.00 1,080.00 Topload balance 1 837.99 0.00 837.99 Topload balance 1 $ 840.44 $ 0.00 $ 840.44 Total $ 17,239.80 $ 5,964.00 $ 23,203.80

None of the equipment purchased has a current fair market value exceeding $5,000.

4. SPECIAL GRANT CONDITIONS A Quality Assurance Project Plan (see Appendix B) was approved by KDOW in October

2007.

89

Quality Assurance Project Plan B

Version 1.2 Date of Last Revision: 10/15/2007 Page 1 of 24

Quality Assurance Project Plan

Geomorphic Assessment and Watershed Implementa-tion Plan for a Sediment Impaired Watershed

UL-WATER-EPPC-05-08 Master Agreement No. M-05296620

Project Plan Developed by Stream Institute

Department of Civil and Environmental Engineering University of Louisville Louisville, KY 40292

Project Plan Developed for Environmental and Public Protection Cabinet

Department for Environmental Protection Kentucky Division of Water

OR Natural Resources and Environmental Protection Cabinet

Department for Environmental Protection Kentucky Division of Water

Nonpoint Source Pollution Control Program

Version 1.2.1 EFFECTIVE DATE OF PLAN: June 14, 2006

PROJECT AND QA MANAGER: Arthur C. Parola, Jr., Ph.D. Professor of Civil and Environmental Engineering University of Louisville Louisville, KY 40292 [email protected] 502-852-4599 502-852-8851 (fax)

mailto:[email protected]


A2 Table of Contents Page Group A: Project Management Elements A1 Title and Approval Page .................................................................................. 1 A2 List of Tables ................................................................................................... 3 A2 List of Figures .................................................................................................. 3 A3 Distribution List ................................................................................................ 4 A4 Project /Task Organization .............................................................................. 4 A5 Problem Definition and Background ............................................................... 6 A6 Project Task Description ................................................................................. 7 A7 Quality Objectives and Criteria ....................................................................... 9 A8 Special Training and Certification ................................................................. 10 A9 Documents and Records .............................................................................. 10 Group B: Data Generation and Acquisition Elements B1 Sampling Process Design (Experimental Design) ........................................ 12 B2 Sampling Methods ........................................................................................ 12 B3 Sample Handling and Custody ..................................................................... 16 B4 Analytical Methods ........................................................................................ 17 B5 Quality Control .............................................................................................. 18 B6 Instrument and Equipment Testing, Inspection, and Maintenance .............. 18 B7 Instrument and Equipment Calibration and Frequency ................................ 18 B8 Inspection and Acceptance of Supplies and Consumables ......................... 19 B9 Non-direct Measurements............................................................................. 19 B10 Data Management ........................................................................................ 19 Group C: Assessment and Oversight Elements C1 Assessment and Response Actions ............................................................. 21 C2 Reports to Management ............................................................................... 21 Group D: Data Validation and Usability Elements D1 Data Review, Verification and Validation ...................................................... 22 D2 Verification and Validation Methods ............................................................. 22 D3 Reconciliation and User Requirements ........................................................ 22 References ........................................................................................................... 23

Appendix B 93

List of Tables

Page Table 1 Final Report Data .................................................................................... 7 Table 2 Sampling Methods ................................................................................ 11 Table 2 Impact ratings from VTANR .................................................................. 13 Table 4 Characteristics of eroding stream banks .............................................. 15

List of Figures Page Figure 1 Organizational Chart Showing Lines of Communication .......................... 6 Figure 2 Definition sketch of cross-section geometry .......................................... 14


Group A: Project Management Elements A3 Distribution List

Mrs. Margi Jones Riparian Management/Restoration Advisor Kentucky Division of Water 14 Reilly Rd. Frankfort, KY 40601 [email protected] 502-564-3410 502-564-0111 (Fax) Michael Croasdaile, Ph.D. Research Associate Department of Civil and Environmental Engineering University of Louisville Louisville, KY 40292 [email protected] 502-852-3220 502-852-8851 (fax)

A4 Project /Task Organization A watershed-based plan, also called a watershed implementation plan (WIP), for the reduction of sediment load or other appropriate measure of sediment impair-ment will be developed for a First Priority section 303(d) listed stream or a stream where a TMDL is under development (KDOW, 2006). The project will be a cooper-ative effort between the University of Louisville (U of L) Research Foundation and the Kentucky Division of Water (KDOW). Through the combined expertise of these organizations, the nine requirements for a watershed implementation project (WIP) provided in US EPA guidelines (2002) will be satisfied. These requirements are:

a) An identification of the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated in this watershed-based plan (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in item (b) immediately below.

b) An estimate of the load reductions expected for the management measures described under paragraph (c) below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time).

c) A description of the NPS management measures that will need to be im-plemented to achieve the load reductions estimated under paragraph (b) above (as well as to achieve other watershed goals identified in this water-shed-based plan), and an identification (using a map or a description) of the



Appendix B 95

critical areas in which those measures will be needed to implement this plan.

d) An estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, to implement this plan.

e) An information/education component that will be used to enhance public understanding of the project and encourage their early and continued partic-ipation in selecting, designing, and implementing the NPS management measures that will be implemented.

f) A schedule for implementing the NPS management measures identified in this plan that is reasonably expeditious.

g) A description of interim, measurable milestones for determining whether NPS management measures or other control actions are being implement-ed.

h) A set of criteria that can be used to determine whether loading reductions are being achieved over time and substantial progress is being made to-wards attaining water quality standards and, if not, the criteria for determin-ing whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised.

i) A monitoring component to evaluate the effectiveness of the implementa-tion efforts over time, measured against the criteria established under item (h) immediately above.

The project QA manager will be Dr. Parola. Dr. Croasdaile, a research associate with training in applied geomorphology, will supervise the field data collection team which will comprise of graduate students and professional staff. Dr Croasdaile, in consultation with the QA Manager, will supervise GIS and map-based data collec-tion. Dr. Parola, the project director, will maintain the official approved QA Project Plan. Figure 1 illustrates the relationships and lines of communication between all pro-ject participants.


Figure 1. Organizational Chart Showing Lines of Communication. A5 Problem Definition and Background Sediment is the second most common cause of impairment of monitored rivers and streams in the United States according to the U.S. Environmental Protection Agency (U.S. EPA, 2000). Sources of sediment often identified as the cause of impairment include agriculture, urban runoff, construction, forestry and unpaved roads. In many environments the majority of sediment supplied to a stream reach is produced by erosion of the streambanks (Rosgen, 1976; Simon et al., 1996). Changes in land-use, removal of riparian vegetation and direct impacts on stream morphology (such as channel straightening) may all lead to increased streambank erosion and hence sediment supply. The goal of this project is to quantify the sediment impairment and determine load reduction or impairment reduction using an integrated watershed-scale and reach-scale assessment. A further goal is to describe management strategies and specif-ic activities (BMP implementation) that are ecologically and morphologically sus-tainable and necessary to achieve estimated reductions in sediment supply.

Local Watershed

Groups

River Restoration Practitioners

Geomorphic Assessment Project

and QA Manager

Data Analysis Team

Field Data Collection

Team

Fieldwork / Data Analysis

Supervisor

KDOW Project Manager

Appendix B 97

A6 Project Task Description Phase I Geomorphic Assessment Using remotely sensed data and limited field survey of stream reaches (windshield survey), a geomorphic assessment will be conducted for the entire watershed or sub-watershed selected. The windshield survey will focus on observations of stream confluences during high flow events to identify which tributary is the major supplier of fine sediment. An attempt will be made to maximize the use of GIS da-tabase information (Table 1). Extensive development of watershed geomorphic assessment protocols have been developed by the Vermont Agency of Natural Resources (VTANR), and it was envisaged that these will form the basis for the Phase I Geomorphic Assessment. However, the GIS program was written for an older version of ArcView which has now been replaced with ESRI ArcGIS. Where possible the protocols outlined in the VTNAR manuals were followed manually in the Phase I assessment. The protocols and GIS software will be evaluated to de-termine its applicability for use in developing a watershed-based plan. Table 1. Data for watershed characterization (modified from USEPA, draft)

Data type Proposed use of data Physical and Natural Features Watershed boundaries • Provide geographic boundaries for evaluation and source control

• Delineate drainage areas at desired scale Hydrology • Identify the locations of waterbodies

• Identify the spatial relationship of waterbodies, including what segments are connected and how water flows through the watershed

Topography • Derive slopes of stream segments and watershed areas (e.g., to identify unstable areas, to characterize segments and sub-watersheds in watershed modeling)

Soils • Identify potential areas with higher erosion rates, or steep slopes Climate • Provide information about loading conditions when evaluated with in-

stream data (e.g., elevated concentrations during storm events and high flow)

Habitat • Describe area’s ability to support aquatic life, and identify areas at risk of impairment • Support defining stressors that could be contributing to impairment • Identify shading or lack of riparian cover • Support identification of potential management or protection areas

Wildlife • Identify special wildlife species to be protected • Identify potential sources of bacteria and nutrients

Land Use and Population Characteristics Land use and land cover • Identify potential pollutant sources (e.g., land uses, pervious vs. impervi-

ous surfaces) • Provide basis for evaluation of sources, loading, and controls

Existing land management practices

• Identify current control practices and potential targets for future manage-ment • Identify potential watershed pollutant sources

Demographics • Provide information on growth rates and potential future growth


Phase II Rapid Geomorphic Reach Assessment The main stem channel of the impaired stream and of major tributaries will be ex-amined to identify sediment sources. In addition, tributaries that appear to be pro-ducing high loads will be examined. Bed level controls and lateral controls, regions of high bed or bank erosion, and sources of woody debris will be identified. Prelim-inary channel classification and conceptual channel evolution models will be de-veloped based on this evaluation. Verification of information determined from Phase I Geomorphic Assessment will be conducted. Reaches identified as produc-ing high sediment loads or sediment deposition will be selected for Phase III De-tailed Stream Survey. Potential reference reaches, bank stabilization, or restora-tion reaches will also be identified. Rapid geomorphic measurements, including bank classification according to the Rosgen BEHI scheme, will be made in these reaches. Hydrologic analyses will be applied to nearby USGS gauging stations or weather stations to identify how representative the sampling period was with re-gard to long-term trends of discharge or precipitation, respectively. Phase III Detailed Stream and Headwater Surveys Reaches identified as “representative” of streams producing high sediment loads, experiencing severe deposition or with stable configuration will be instrumented to produce estimates of the suspended sediment load. The development of a stage-discharge relationship requires that discharge be measured over a wide range of flows. To reduce the risk of wading in deep, fast flowing water, sites with bridges across the channel will be favored as measuring sites. The detailed measurements will provide a basis for estimation of loads and identification of reference condi-tions. To estimate the total channel network that is contributing water and sediment to the watershed, the start of headwater channels will be surveyed. The sites will be based on accessibility, although a number of lower order streams will be exam-ined. Estimates of the sediment input from overland flow on the hillsides will be calculated from old farm ponds. These small depressions trap incoming sediment and the sediment contribution from overland flow can be approximated by dividing the volume of sediment stored in the pond by the time over which the pond has been active. The use of pond cores that represent over 20 to 30 years of sediment accumulation should remove short-scale trends due to drought years or years with unusually high rainfall and the associated changes in sediment production.

Appendix B 99

Stream Assessment Report The University of Louisville Research Foundation (ULRF) will request current Final Project and Closeout Report guidelines from the Kentucky Division of Water no less than six months prior to the project end date. The Watershed Assessment Report will present the data and analysis of each phase of assessment in a clear and standard format. The data from the studied watershed will be stored in a data-base that will be submitted to the Kentucky Division of Water. The Kentucky Divi-sion of Water, Nonpoint Source Section, will receive an electronic copy of the data. Watershed Management Strategies Nonpoint Source management activities such as overland erosion control, bank protection, stream restoration, riparian buffer zone planting will be developed and sediment load reduction based on these activities will be estimated. Cost estimates of the recommended activities and an implementation schedule based on priorities for successful reduction will be developed. A sediment monitoring plan will be de-veloped to measure the success of implemented BMPs and to identify required modifications to the Watershed Implementation Plan. Criteria will be developed to determine whether sediment load reductions are achieved over time. Watershed Implementation Plan The project will be a cooperative effort between the University of Louisville (U of L) Research Foundation and the Kentucky Division of Water (KYDOW). Through the combined expertise of these organizations, all components of the WIP will be as-sembled and a final watershed implementation plan document will be jointly pub-lished by the University of Louisville Research Foundation and the Kentucky Divi-sion of Water. A7 Quality Objectives and Criteria The objectives of this study are to clearly identify major sediment problems, to col-lect information to quantify the degree of this impairment and develop a practical watershed-based plan from this information. The identification of sediment impair-ment will be conducted at a range of spatial scales, reflecting different levels of de-tail and precision of data collection. Phase I Geomorphic Assessment will utilize GIS-based remotely sensed data and field data including field observations and photographic documentation. The loca-tion of the field measurements will be recorded using a hand held global position-ing system (GPS) unit. The GIS based analysis will utilize a wide array of geospa-tial information which is provided by the Commonwealth of Kentucky and available online. The individual geospatial datasets are made available by different organiza-tions including the United Sates Geological Survey (USGS), the Kentucky Geolog-ical Survey (KGS), and the Kentucky Division of Geographic Information (KDGI). Each GIS-based dataset used by ULRF will be consistent with Federal Geographic Data Committee (FGDC) endorsed standards.


Three general types of data will be collected during Phase II and III Assessments: stream geometric characteristics, sediment samples and water stage readings. Es-timates of bank erosion will be developed from repeated monitoring of erosion pins (3ft pins driven horizontally in to the bank). Bank erosion rates measured using erosion pin method have an accuracy of less than 1cm. Sediment sampling will be used to determine the size of material that is supplied to the stream by streambank erosion. Standard sieve analysis and evaporation procedures employed by the geomechanics laboratory using standard ASTM techniques for fine and coarse aggregates will provide data for sediment size gradation to high precision. Amounts of gravel required to characterize the active streambed will be determined according to Bunte and Abt (2001), Rosgen (1996). Flow stage measurements will be obtained using pressure transducers accurate to 0.05% of the total flow depth. To calculate discharge from the stage measurements, flow will be measured at each site using Acoustic Doppler Velocitmeters (ADV) or an Acoustic Doppler Current Profiles (ADCP). The USGS has considerable experience in flow gauging and USGS protocols for measuring flow will be followed. Where necessary, crest gages that measure the peak stage only will be installed to supplement other flow and stage measurements. A8 Special Training and Certification The QA manager and project team have academic as well as professional training in applied geomorphology and the techniques necessary to collect and analyze the required geomorphic data. This training includes extensive academic and profes-sional training in surveying, sediment sampling, hydraulic and hydrologic modeling and geomorphic assessment. No in-stream sampling is performed by a single person. A sampling crew should always include at least 2 people. If flows are high or weather poses a risk, deci-sions should always be made with the safety of the personnel as the main con-cern. Any on-the-job accidents will be immediately reported to a supervisor. The supervisor will notify the proper people according to procedures outlined by the Worker’s Compensation Insurance carrier and departmental policy. A9 Documents and Records The QA manager will be responsible for ensuring that the data collection team and all others on the distribution list receive the most current QA project plan through email distribution. A watershed-based plan (WBP), sometimes called a watershed implementation plan (WIP), will be produced. All components of the plan shall be assembled and

Appendix B 101

distilled into a final watershed implementation plan document jointly published by the University of Louisville Research Foundation and the KYDOW. A final report that documents the procedures used to collect the data (Table 2), dif-ficulties in the data collection process, and factors that influenced data quality will be produced. The final report will include the raw field data in a Microsoft Excel format. Table 2. Final Report Data Type of Data Source Data Analysis Site location, geology, and topographic data

USGS topo maps, KY geologic maps, state GIS database

Delineation of study reaches and identification of stream disturbances

Watershed assess-ment

Field observations and GPS data collected by field team

Characterization of stream morpholo-gy and stability

Cross-sectional stream characteristics

Geometric data collected by field team

Streambank profiles will provide esti-mates of bank and bed erosion rates and quantity of sediment supplied

Bank (at different stra-ta) and bed (surface and subsurface) sed-iment characteristics

Samples collected by field team (Phase II and III) supported by photographic documentation col-lected by field team (used to es-timate sediment characteristics at un-sampled reaches)

Bed and bank material classification; quantification of different material siz-es supplied through bed and bank erosion

Flow stage Pressure transducers Quantification of the forces acting on the bed and banks to produce erosion and the duration of high flow events during the project

Discharge ADV and ADCP Measure discharge and through crea-tion of stage-discharge relationship, calculate the volume of flow for an entire flood event

Suspended sediment samplers

Single stage modified US-U59B samplers

Take water samples from 5 stages in the water column. These samplers are analyzed for suspended sediment concentration, which is then com-bined with volume of water to calcu-late a total sediment load.


Group B: Data Generation and Acquisition Elements B1 Sampling Process Design (Experimental Design) The watershed to be assessed will be Goose Creek, a sub-watershed of Benson Creek, about 6 miles west of Frankfort. Both Goose Creek and Benson Creek were selected from First Priority streams on the 303(d) list as described in Part II of the Integrated Report (KDOW, 2006). The 303(d) list refers to specific stream reaches, the drainage area of which will vary from small watersheds (<10 square miles) to very large streams (<1000 square miles). For large watersheds, it is not feasible to make field measurements along the entire stream length, whereas in small watersheds the field survey may encompass the entire non-gully channel network. Hence, a nested approach was taken whereby detailed measurements were taken at Goose Creek (drainage area of 10 square miles), and some instru-mentation was installed in Benson Creek (100 square miles) to evaluate how well measurements from a smaller watershed are scalable to a larger watershed, where field reconnaissance of the entire stream network is not feasible.

For Goose Creek, the watershed will be divided into the main stem, major tributaries and minor tributaries. A reconnaissance of these streams will be made by vehicle and from existing geospatial datasets (Phase I). From the initial as-sessment of stream condition, a preliminary classification of each stream as de-grading (eroding), aggrading (depositing) or stable, will be made. From these streams, representative reaches will be selected for further study. Priority will be given to stream reaches that appear to be the site of recent morphological change through high levels of sediment erosion or deposition, and to reaches that appear to be stable. Phase II and III will involve more comprehensive assessment of the individual stream reaches using a rapid assessment procedure (Phase II) and a suspended sediment load measurements (Phase III). Phase II Rapid Geomorphic Reach Assessment will provide a database of existing channel conditions and al-low comparisons of channel geometric properties between different stream reach-es to be made. This comparison, coupled with field observations, will be used to verify the classification made during Phase I, and to identify problem reaches for further study in Phase III Detailed Stream Surveys. During Phase III, flow data will be collected, to estimate the forces acting on the bed and the banks and to evalu-ate the duration, frequency and magnitude of sediment-transporting events. Sites on Benson Creek will be selected according to confluences with major tributaries. B2 Sampling Methods Phase I Geomorphic Assessment All available relevant geospatial datasets (see Table 1) for the selected watershed will be downloaded and imported into GIS. From these map coverages the drain-age area and stream length will be calculated for the main stem and major tributar-ies. Disturbances due to land use changes, agriculture, vegetative clearing, direct channel modifications, and construction (including roads and buildings) will be

Appendix B 103

evaluated from topographic maps, aerial photographs and land cover maps. The geology of each stream will be assessed, including the degree of karst (if any) and any faults or other structural control of the landscape. A valley profile will be plotted for the main stem and major tributaries. The valley profile shows the slope of the valley flat which controls the maximum slope of the stream bed and hence influ-ences the erosive capacity of the stream channel. The drainage area, stream length, geology, valley profiles and other GIS-based parameters will be obtained following, as closely as possible, the guidelines in the VTANR Phase I Assessment Handbook (VTANR, 2004). When existing geospatial data sets have been imported into a GIS and watershed areas and stream lengths calculated, the GIS files will be uploaded to a handheld GPS receiver. The GPS receiver will be the primary means of field data collection for the Phase I Geomorphic Assessment. The field survey will aim to cover as much of the watershed as possible, which is dependent on the local road network. At each road crossing the survey team will record the position of the channel using the GPS unit. The survey team will proceed upstream taking photographs, making field observations and recording the position of relevant stream, valley and hillslope features. The field assessment will follow the “Bed and Bank Windshield Survey” procedures as described in VTANR (2004, p.63-67). The Phase I Geomorphic Assessment will provide impact ratings based on the protocols described in VTANR (2004) and shown in Table 3, below. Impact Score Impact Description Description

2 High (H) Strongly evident – highly significant 1 Low (L) Evident – may be significant 0 Not significant (NS) Not evident – insignificant 0 No info / not rated Unknown – no data collected

Table 3. Impact ratings from VTANR The impact rating will be developed from the following data categories:

1. Land use 2. Channel modification 3. Floodplain modification 4. Bed and bank windshield survey

The scores will then be summed to provide a Total Impact score which will be used to determine stream reaches for the Phase II Rapid Geomorphic Reach As-sessment. Phase II Rapid Geomorphic Reach Assessment The main stem of the impaired watershed and the major tributaries will be exam-ined to identify major sediment sources. Any tributaries that were identified as sig-nificant sources of sediment in the Phase I Geomorphic Assessment will also be examined. The entire stream network as shown by the blue line streams on the


USGS 7.5 minute topographic quadrangle will be walked and inventoried. Smaller streams that do not appear on the topo maps will be examined if the Phase I Ge-omorphic Assessment identified a particularly disturbance in the upper reaches of the watershed. The rapid geomorphic assessment will include rapid cross-sectional measurements, documentation of bed and bank material characteristics, vegetative cover, sources of woody debris and channel controls (both lateral and vertical), such as bridges, weirs, culverts, and bank protection. Where the channel cross-section geometry is complex, the geometry will be measured using a line level, tape measure and pocket rod to describe the cross section with an accuracy of ±0.5 cm in the vertical and horizontal directions (Fig-ure 2). Simple trapezoidal cross-sections will be measured using top width, bed with and a depth. Bed and bank material characteristics will be recorded by photo-graphic documentation and the results will be ‘calibrated’ by comparing photos with those taken at sites where sediment samples were collected in the Phase III De-tailed Stream Survey (see next section). In this way the grain size distribution of the bed and bank materials can be estimated along the entire study reach. Photo-graphic documentation will be made of the bank condition (in terms of stability and mode of mass failure) along the stream length. The location of all measurements and photographs will be recorded using a GPS.

Figure 2. Definition sketch of cross-section geometry.

Appendix B 105

Phase III Estimation of suspended sediment loads from stream banks will be accomplished using the Bank Erosion Hazard Index (BEHI) approach described in Rosgen (2001). The approach has been applied in the Western US and was recently used in Arkansas to measure sediment loads on a 303(d) listed stream by Formica et al. (2004). The BEHI approach involves classifying section of eroding banks accord-ing to the following parameters: bank height ratio (stream bank height/maximum bankfull depth), ratio of rooting depth/bank height, rooting density, per cent surface area of bank protected, bank angle, number and location of various soil composition layers or lenses in the

bank, and bank material composition.

The field measured variables assembled as predictors of erodibility (BEHI) are then converted to a risk rating of 1-10 (10 being the highest level of risk). The risk rating range from 1 to 10 and correspond to adjective values of risk (very low, low, moderate, high, very high, and extreme potential erodibility). The total points ob-tained from the measured bank variables are then converted to an overall risk rat-ing (Table 4).

Table 4. Characteristics of eroding stream banks used to develop the BEHI for a particu-lar watershed (from Rosgen, 2001). The Detailed Stream Survey will be conducted at reaches “representative” of streams producing high sediment loads, experiencing sever deposition or at refer-ence reaches. Single stage sediment samplers will be used to measure the sus-pended sediment load. The design of the samplers will be based on U.S. U-59B, which is detailed in the Federal Inter-agency Sedimentation Project Report number


13 (FISP, 1961). Further details about the deployment of these samplers and some of their limitations are provided in Edwards and Glysson (1999). The sam-plers will be installed at various locations within the watershed to monitor the flux of sediment and identify the sources of elevated loads. At each suspended sedi-ment sampler site, a stage-discharge curve will be developed using flow meas-urement devices. The volume of water passing a sampler will be combined with the suspended sediment concentration estimates from the sampler to produce a calculated volume of sediment for each flow event. The total volumes for each event over the annual sampling period will be summed to produce an annual load estimate. Grab samples will be collected on an opportunistic basis from the center of the stream channel and compared to the suspended sediment concentrations form the samplers. This comparison will be used to evaluate the representative-ness of samples collected adjacent to the stream bank (from the single stage samplers) relative to the flow in the centre of the channel (grab samples). To estimate the volume of sediment produced from the unchannelized portion of the watershed, a different approach is required to compliment the bank erosion pins used downstream. Depending on the availability of reservoirs, a coring pro-gram will be developed to measure sediment trapped in farm ponds or small lakes. This method has been used in other sediment budget studies and is a useful tech-nique to obtain estimates of sediment production over geomorphically significant time scales (10 to 80 years). Details on pond coring and how it can be used to es-timate the volume of sediment supplied to the downstream channel network are summarized in Royall (2003). The Detailed Stream Survey will be repeated at the same sites, approximately one year after the initial field survey. Toe pins and survey hubs will be used to identify the precise locations of the original survey and to ensure that the survey locations are identical. The repeat survey will be used to estimate rates of erosion from vol-umetric differences in the bank profiles and from the erosion pins. Photographs will be taken of the measured cross-sections, bankfull indicators, bank and bed sedi-ments, zones of erosion and deposition, and the overall valley configuration. B3 Sample Handling and Custody Positional data from the GPS receiver (Phase I Geomorphic Assessment) will be collected in electronic format on an integrated data logger and will be downloaded at the end of each day of field work and stored in electronic format (Excel spread-sheet) under the supervision of the field work supervisor. Data collected during the field surveys will be entered into (Phase II) or downloaded to (Phase III) electronic spreadsheet format at the end of each day of field work. Digital photographs will be downloaded to a portable computer at the end of each day of field work. Field ob-servations and notes will entered in to word processing software. Field observa-tions and measurements from the erosion pins will be recorded on data forms to complement the GPS measurements and aid in interpretation of photographs. Notes and field sketches will be entered into electronic format. Photographic doc-

Appendix B 107

umentation will be taken using a high-quality digital SLR camera and will be down-loaded at the end of each day. The data will be stored during the field work by fieldwork supervisor and archived on a bi-weekly or monthly basis by the project QA manager. The archived data will be stored on a separate external hard drive and locked in a safe. B4 Analytical Methods The bank erosion hazard index (BEHI) methodology proposed by Rosgen (2001) will be used in this project to estimate the erosion potential of stream banks in the selected watershed. The procedure used to apply the BEHI method will be as fol-lows:

1. An inventory of stream banks will be conducted based on an estimate of the bank erosion hazard index and the near-bank shear stress (NBSS).

2. Erosion rates at selected sites will be measured using erosion pins and/ or repeat surveying.

3. At each stream bank inventoried, the measured erosion rates will be com-pared to the BEHI and NBSS values.

4. A graphical model will be developed from the measurements of erosion rates, BEHI and NBSS to predict erosion rates at other sites where the ero-sion rate was not measured.

5. The graphical method will be applied to other inventoried stream banks to enable prediction of the sediment load produced through stream bank ero-sion in the selected watershed.

Further details of the BEHI method and its application to estimating sediment loads at the watershed scale are presented in Rosgen (2001) and Formica et al. (2004) Flow meter data will be analyzed in software provided by the instrument manufac-turer. The ADV is made by Sontek and the accompanying “Flowtracker” software is designed to convert the flow velocity measurements in to a discharge across the measured cross-section. The ADCP is manufactured by RDI Teledyne and comes with “StreamPro” software that also outputs a discharge from field measurements of flow velocity. Both programs provide estimates of the error and uncertainty for each discharge estimate allowing Quality Control checks to be performed during data analysis. Survey data will be analyzed and reduced using Microsoft Excel. All data will un-dergo quality control checks supervised by the QA manager during data pro-cessing to ensure satisfactory quality throughout the spreadsheet analysis. The GPS data will be analyzed and mapped using ArcMap GIS software. The cal-culation of drainage area and the extraction of longitudinal valley profiles will be conducted in ArcMap and the data entered into Excel for further analysis.


B5 Quality Control Data will be verified by reviewing excel data sheets and comparing the spread-sheet to printouts of the information recorded on the handheld GPS receiver. This will be done initially by the person performing the data entry. Locations of field sur-vey points will be plotted on USGS topographic 7.5 minute quadrangles and in-spected by the Quality Manager. The location of the photographic documentation will be verified by comparing time stamps of the photograph and the corresponding GPS point. All data collected will be reviewed by the Data Analysis Supervisor and additional quality checks will be periodically performed by the Quality Manager. Data collected during the extensive survey will be downloaded to electronic spreadsheet format at the end of each day of field work. The plan and profile view of the survey data will be compared to the photographic documentation and USGS topographic 7.5 minute quadrangle maps to ensure correct survey procedures were followed. Survey data that do not conform to the mapped and photographed topography will be manipulated in AutoCAD software to correct known sources of rotation or translation. Data that cannot be rectified using AutoCAD will be reject-ed. Surveying of cross sections in the field using the line level and pocket rod will be performed by field-trained personnel under the direct supervision of the QA man-ager or the fieldwork supervisor. Discharge measurements will be checked in the field and repeated if errors fall outside the quality control bounds specified on both the ADV and the ADCP. Once downloaded, the software for the stream flow measurements devices provide es-timates of the error and uncertainty for the discharge data allowing Quality Control checks to be performed during data analysis. All maps used within the ArcGIS analysis will be obtained from reliable electronic sources and checked against hard copy maps to ensure accurate georeferencing. All calculations and parameters from ArcGIS will be field checked by the data analysis manager if appropriate. Periodic reviews of the data analysis will be per-formed by the QA manager, who will review all data prior to inclusion in the final report. B6 Instrument/Equipment Testing, Inspection, and Maintenance B7 Instrument/Equipment Calibration and Frequency Instruments are calibrated and maintained according to specifications as outlined in the owner’s manual for that piece of equipment. All instruments will be calibrated prior to leaving the central office for each trip. Calibration may also be performed when in the field. A logbook of the repairs made will be kept for each piece of elec-tronic equipment. When possible, equipment will be inspected once every two

Appendix B 109

years by a repair technician for general maintenance and to verify that it is func-tioning correctly for each parameter. All calibration, maintenance and repairs will be noted in the logbooks for that piece of equipment. Annually, a precision test will be performed on all equipment to verify proper functioning. Any equipment that is not functioning properly will be repaired. B8 Inspection/Acceptance of Supplies and Consumables There are no project-specific inspection/acceptance criteria for supplies and consumables. It is standard operating procedure that: personnel will not use broken or defective materials; items will not be used past their expiration date; supplies and consumables will be checked against order and packing slips to verify that the correct items were received; and the supplier will be notified of any missing or damaged items. All purchases over $100 will be approved by the QA manager.

B9 Non-direct Measurements Review of all sample sites is performed through aerial photography available on ArcMap GIS 9.2. This information is used to help determine impacts on sampling sites. Coverages for KPDES outfalls, CAFO’s, AFO’s, gas and oil wells and other human disturbances may be used to help assess a stream prior to sampling. In-formation obtained from ArcMap will be verified in person when at all possible. The Branch Manager and his designees will determine if information from other sources will be accepted and used in making assessments. In order to be consid-ered for acceptance, the other source must present their SOPs, QAPP and pro-cessed data. Data will be verified to ascertain if it is reasonable for the site sam-pled and to help determine if proper procedures are being followed. B10 Data Management The data sets (including metadata), study results (including geomorphic descrip-tions), and final project documents in the appropriate electronic format will be made available at the time of final report publication. Digital backups of the GPS data, photographic documentation and field notes will be made on writable CD or DVD format at the end of each week of field work. A separate hard drive will be used to archive files and will be stored in a locked safe when not in use. A minimum of 10% of all data entry will be checked by another person. If data en-try does not meet data quality objectives, re-training will be performed by the sec-tion supervisor or other designated individuals. Follow up quality assurance will be performed to ensure that methods have been corrected. Inadequate or otherwise faulty methods may determine whether or not data will be used for assessment purposes.


Following completion of the project all data will be stored in electronic format at the University of Louisville for no less than 3 years.

Appendix B 111

Group C: Assessment and Oversight Elements C1 Assessment and Response Actions Assessment of data quality will be conducted at several levels. Survey equipment will be examined to determine its accuracy by laying out a known measurement distance and by recording repeat measurements each time the equipment is taken into the field. Equipment will be checked quarterly, at a minimum, to verify that it is in proper working order. Equipment that is not functioning properly will be repaired, pending funding and departmental approval. The QA manager will make visits to field sites during part of each field reconnais-sance to ensure that procedures described here are being followed. The project team will discuss procedures and assess errors in measurements at least biannu-ally. Data collection will be repeated if necessary. Correct functioning of the GPS receiver is imperative for the Rapid Field Survey. At least one backup instrument will be made available to ensure that a GPS receiver is used. Personnel will undergo an annual review process. This consists of two interim re-views and a final review. This allows discourse between the supervisor and staff and helps ensure corrective actions are taken before much time has passed. In the event that staff is not meeting expectations, action will be taken to help remediate the situation and further evaluation will be conducted. Inadequate or otherwise faulty methods may determine whether or not data will be used for assessment purposes. C2 Reports to Management Verbal reports on the status of projects will be made weekly. Data collection pro-cedures will be discussed, problems will be addressed, and any necessary correc-tive actions will be taken on a weekly basis. The QA manager and field data collec-tion team will meet to discuss QA and QC issues before each intensive field data collection period.


Group D: Data Validation and Usability Elements D1 Data Review, Verification and Validation Checks of data using a tape measure will be made to ensure that survey data are within an acceptable range for characterizing geomorphic parameters. Most prob-lems with data error will be addressed at the time of data collection. D2 Verification and Validation Methods The geomorphic data and erosion rate date for this project will be compared to those of other similar projects of regional geomorphic characteristics (c.f. Rosgen, 2001; Formica et al., 2004). Data incorporated in the database will be reviewed and tested by the QA manager. Although large variation in geomorphic parameters is anticipated, unusual deviations will be examined carefully to ensure that they represent variation in geomorphic characteristics and not error of data collection and analysis procedures. D3 Reconciliation and User Requirements Data from geomorphic assessments will be made available to KY DOW Water Quality Branch and Watershed Management Branch to aid with technical reports to stake holders. The Geomorphic Assessment report and the resulting Watershed Implementation Plan developed from the assessments will also be provided to Kentucky Division of Water to disseminate to interested parties. In addition, users will be cautioned that local and basin conditions may cause sub-stantial differences in stream characteristics. The database will provide information on the characteristics of streams and their watersheds so that users have infor-mation available to make direct comparisons with specific site conditions. Following completion of the project all data will be stored in electronic format at the University of Louisville for a minimum of 3 years.

Appendix B 113

References Bunte, K. and Abt, S.R. 2001. Sampling surface and subsurface particle-size dis-

tributions in wadable gravel-and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring. Gen. Tech. Rep. RMRS-GTR-74. Fort Collins, CO: US Department of Agriculture, Forest Service, Rocky Mountain Research Station. 428 p.

Edwards, T.K. and G.D. Glysson. 1988. Field methods for measurement of fluvial

sediment. U.S. Geological Survey. Open File Report 86-531. Reston, VA. Federal Inter-Agency Sedimentation Project (FISP), 1961. The single-stage sam-

pler for suspended sediment. Minneapolis, Minnesota, St. Anthony Falls Hy-draulics Laboratory, Inter-Agency Report 13, 105 p.

Formica S.J., Van Eps M.A., Nelson M.A., Cotter A.S., Morris T.L., and Beck J.M.

2004. West Fork White River Watershed - Sediment Source Inventory and Evaluation. ASAE., Pub. Date 12 September 2004 . ASAE Pub #701P0504.

Harrelson, C.C., Rawlins, C.L., and Potyondy, J.P., 1994, Stream channel refer-

ence sites – An illustrated guide to field technique: U.S. Department of Agricul-ture Forest Service General Technical Re-port RM-245, 61 pp.

Kentucky Division of Water, 2006. Integrated Report to Congress on the Condition

of Water Resources in Kentucky. Kentucky Environmental and Public Protec-tion Cabinet Division of Water, Frankfort, KY.

Rosgen, D.L. 1976. The Use of Color Infrared Photography for the Determination

of Suspended Sediment Concentrations and Source Areas. In: Proceedings of the Third Inter-Agency Sediment Conference, Water Resources Council. Chap. 7, 30-42.

Rosgen, D.L., 1996, Applied River Morphology (Second Edition). Wildland Hydrol-

ogy, Pagosa Springs, CO. Rosgen, D.L. 2001. A practical method of computing streambank erosion rate. p.

9–15. In Proc. 7th Federal Interagency Sedimentation Conference, Reno, NV. 25–29 Mar. 2001. Vol. 2. USGS, Reston, VA.

Royall (2003) A fifty-year record of historical sedimentation at Deer Lake, North

Carolina. The Professional Geographer, 55(3): 356–371 Simon, A., Rinaldi, M. and Hadish, G. 1996. Channel evolution in the loess area of

the Midwestern United States. Proceedings of the Sixth Federal Interagency Sedimentation Conference, Las Vegas, NV, III-86-III-93.


U.S. Environmental Protection Agency (USEPA). 2000. National Water Quality In-ventory: 2000 Report to Congress. Online resource: http://www.epa.gov/305b/2000report/ Accessed June 15, 2006.

U.S. Environmental Protection Agency (USEPA). 2003. Supplemental Guidelines

for the Award of Section 319 Nonpoint Source Grants to States and Territories in FY 2003.

Online Resource: http://www.epa.gov/owow/nps/Section319/319guide03.html Accessed June 19, 2006. U.S. Environmental Protection Agency (USEPA). Draft manuscript. EPA Handbook

for Developing Watershed Plans to Restore and Protect Our Waters. Online re-source: http://www.epa.gov/nps/watershed_handbook/

Accessed June 19, 2006. Vermont Agency of Natural Resources (VTANR). 2004. The Stream Geomorphic

Assessment Handbooks and Database. Online resource: www.vtwaterquality.org/rivers.htm Accessed June 19, 2006.

http://www.epa.gov/305b/2000report/

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http://www.epa.gov/nps/watershed_handbook/

http://www.vtwaterquality.org/rivers.htm

115

BMP Reach Summaries C

Appendix C 117

Reach ID: GC2 Reach length: 2690 ft Reach type: Intermittent Drainage area: 7.89 mi2 upstream

8.09 mi2 downstream Impairment indicator: Channel entrenchment and predominatly planar bedrock channel bed. Riffles are infrequent and short. Pool habitat is very limited, and riffles are dry in the summer. Pollutant sources: Eroding high banks and small tributaries supplying fine sediment

BMP: Stream restoration to increase habitat diversity, increase pool depths, and lower floodplain, reducing length and height of eroding banks and providing floodplain storage zones to reduce sediment supply from tributaries. Surface water and groundwater data would be useful in determining whether water table can be raised locally.

Impairment reduction: 25% of riffles were rated more than 50% embedded. Improvement to 100% of riffles less than 50% embedded.


Reach ID: GC5 Reach length: 1562 ft Reach type: Intermittent Drainage area: 0.72 mi2 upstream

0.92 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Numerous eroding high banks and small tributaries supplying fine sediment

BMP: Stream restoration to lower floodplain, reducing length and height of eroding banks and providing storage zones to reduce sediment supply from tributaries.


Appendix C 119

Reach ID: GCT2 B/C Reach length: 4367 ft Reach type: Intermittent Drainage area: 0.17 mi2 upstream

1.04 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Eroding high banks and ditched tributaries with unvegetated banks and very poor riparian buffers

BMP: Stream restoration to lower floodplain and reduce length and height of eroding banks. Stabilization of tributaries with splay areas to trap sediment.



Reach ID: GCT3 DS Reach length: 2295 ft Reach type: Intermittent Drainage area: 0.39 mi2 upstream

0.49 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Many eroding banks and ditched tributaries supplying fine sediment. Downstream end is also backwatered by Goose Creek and a narrow bridge over Bardstown Trail (CR-1122).

BMP: Creation of a sediment storage zone at downstream end of reach. Lowering of GCT3 and ditch bank heights, and stabilization of ditches to reduce local sediment supply and embeddedness. Impairment reduction: 75% of riffles were rated more than 50% embedded. Improvement to 100% of riffles less than 50% embedded.

Appendix C 121

Reach ID: GCT3 US Reach length: 1346 ft Reach type: Intermittent Drainage area: 0.12 mi2 upstream

0.21 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Eroding high banks, undercut hillsides, and small tributaries (gullies) supplying sediment during base flow in GCT3

BMP: Stream restoration to reduce GCT3 bank heights and percentage eroding banks, reduce bank heights and percentage eroding banks on tributaries (gullies), and create wetlands and storage zones.



Reach ID: GCT4 Reach length: 2069 ft Reach type: Intermittent Drainage area: 0.19 mi2 upstream

0.3 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Numerous eroding high banks, undercut hillsides, and small tributaries supplying sediment during base flow in GCT4

BMP: Stream restoration to reduce main stem bank heights and percentage eroding banks; reduce bank heights and percentage eroding banks on tributaries; create wetlands and storage zones; stabilize gullies; BMP implementation in upstream unmapped GCT4 (see next page).


Appendix C 123

Reach ID: Unmapped GCT4 headwaters Total surface area: 23 hectares Total upland erosion load: 225 tons/yr Total unmapped stream length: 4359 ft Potential load reduction: 113 tons/yr BMP: Gully stabilization Estimated cost: $250,000-350,000

Example of unmapped channel morphology in the headwaters of GCT4.


Reach ID: BB5 Reach length: 3210 ft Reach type: Intermittent Drainage area: 0.57 mi2 upstream

1.48 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Numerous eroding high banks and small tributaries supplying fine sediment

BMP: Stream restoration to lower floodplain and reduce length and height of eroding banks; stabilize tributaries (gullies).


Appendix C 125

Reach ID: BBT3 DS Reach length: 3564 ft Reach type: Intermittent Drainage area: 0.61 mi2 upstream

0.84 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Eroding hillsides, very high banks, and small tributaries delivering fine sediment

MP: Stream restoration; stabilization of gullies. pairment reduction: 57% of riffles were rated

more than 50% embedded. Improvement to 100% of riffles less than 50% embedded.


Reach ID: BBT3 US Reach length: 3213 ft Reach type: Intermittent Drainage area: 0.1 mi2 upstream

0.49 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Eroding hillsides, very high

banks, and small tributaries delivering fine sediment

BMP: Stream restoration; stabilzation of small tributaries (gullies); BMP implementation in upstream unmapped BBT3 (see next page).


Appendix C 127

Reach ID: Unmapped BBT3 headwaters Total surface area: 54 hectares Total upland erosion load: 513 tons/yr Total unmapped stream length: 9697 ft Potential load reduction: 257 tons/yr BMP: Gully stabilization Estimated cost: $400,000-500,000

Example of unmapped channel morphology in the headwaters of BBT3.


Reach ID: BBT6 Reach length: 2094 ft Reach type: Intermittent Drainage area: 0.1 mi2 upstream

0.26 mi2 downstream Impairment indicator: Embedded riffles Pollutant sources: Eroding banks and hillsides.

BMP: Stream restoration to lower floodplain, reducing length and height of eroding banks. Two small culverts should be assessed to determine whether they could be widened.
