2017 annual dam and dike inspection report · 10/18/2001 · this document also uses the...

2017 Annual Dam and Dike Inspection Report

Ash Pond Complex

Conesville Plant

AEP Generation Resources, Inc.

Coshocton County, Ohio

October 23, 2017

Prepared for: AEP Generation Resources – Conesville Plant

Conesville, Ohio

Prepared by: American Electric Power Service Corporation

1 Riverside Plaza

Columbus, OH 43215

GERS-17-045

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Pages 4 of 11

Table of Contents 1.0 Introduction ............................................................................................................................................. 6

2.0 Description of Impoundment .................................................................................................................. 6

2.1 Definitions of Visual Observations and deficiencies .......................................................................... 6

2.2 Fly Ash Pond Complex ....................................................................................................................... 7

3.0 Review of Available Information (257.83(b)(1)(i)) ................................................................................ 7

4.0 Inspection (257.83(b) (1)(ii)) .................................................................................................................. 8

4.1 Metals Cleaning Waste Tank Dike (Non-CCR).................................................................................. 8

4.2 Ash Pond Complex ............................................................................................................................. 8

4.2.1 Changes in geometry since last inspection (257.83(b)(2)(i)) ....................................................... 8

4.2.2 Instrumentation (257.83(b)(2)(ii)) ............................................................................................... 8

4.2.3 Impoundment Characteristics (257.83(b)(2)(iii, iv, v)) ............................................................... 8

4.2.4 Visual inspection (257.83(b)(2)(i)) .............................................................................................. 9

4.2.5 Changes that effect stability or operation (257.83(b)(2)(vii)) .................................................... 10

5.0 Summary of Findings ............................................................................................................................ 10

5.1 General Observations ........................................................................................................................ 10

5.2 Maintenance Items ............................................................................................................................ 10

5.3 Items to Monitor ............................................................................................................................... 11

5.4 Deficiencies (257.83(b)(2)(vi)) ......................................................................................................... 11

Attachments Attachment A – Pictures Attachment B – Site Maps Attachment C – Instrumentation Data

Pages 5 of 11

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1.0 Introduction This report was prepared by AEP- Geotechnical Engineering Services (GES) section, in part, to fulfill requirements of 40 CFR 257.83 and the Ohio Department of Natural Resource (ODNR), Division of Water Dam Inspection Section and to provide AEP Generation Resources and the Conesville Power Station with an evaluation of the facility. Ms. Beth Mullen, Plant Environmental Coordinator for the Conesville Plant provided onsite coordination for inspection activities. The inspection was performed on October 23, 2017 by J.T. Massey-Norton of AEP Geotechnical Engineering. Weather conditions were overcast with temperatures in upper-50̊s F to Lower-60̊s F and no precipitation occurred in the preceding seven days prior to the inspection.

2.0 Description of Impoundment

2.1 Definitions of Visual Observations and deficiencies This summary of the visual observations uses terms to describe the general appearance or condition of an observed item, activity or structure. The meaning of these terms is as follows:

Good: A condition or activity that is generally better or slightly better than what is minimally expected or anticipated from a design or maintenance point of view.

Fair or A condition or activity that generally meets what is minimally Satisfactory: expected or anticipated from a design or maintenance point of view.

Poor: A condition or activity that is generally below what is minimally expected or anticipated from a design or maintenance point of view.

Minor: A reference to an observed item (e.g., erosion, seepage, vegetation, etc.) where the current maintenance condition is below what is normal or desired, but which is not currently causing concern from a structure safety or stability point of view.

Significant: A reference to an observed item (e.g. erosion, seepage, vegetation, etc.) where the current maintenance program has neglected to improve the condition. Usually, conditions that have been previously identified in the previous inspections, but have not been corrected.

Excessive: A reference to an observed item (e.g., erosion, seepage, vegetation, etc.) where the current maintenance condition is above or worse than what is normal or desired, and which may have affected the ability of the observer to properly evaluate the structure or particular area being observed or which may be a concern from a structure safety or stability point of view.

This document also uses the definition of a “deficiency” as referenced in the CCR rule section §257.83(b)(5) Inspection Requirements for CCR Surface Impoundments. This definition has been assembled using the CCR rule Preamble as well as guidance from MSHA, “Qualifications for Impoundment Inspection” CI-31, 2004. These guidance documents further elaborate on the definition of deficiency. Items not defined by deficiency are considered maintenance or items to be monitored.

A “deficiency” is some evidence that a dam has developed a problem that could impact the structural integrity of the dam. There are four general categories of deficiencies. These four categories are described below:

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1. Uncontrolled Seepage a. Uncontrolled seepage is seepage that is not behaving as the design engineer has

intended. An example of uncontrolled seepage is seepage that comes through or around the embankment and is not picked up and safely carried off by a drain. Seepage that is collected by a drain can still be uncontrolled if it is not safely collected and transported, such as seepage that is not clear. Seepage that is unable to be measured and/or observe it is considered uncontrolled seepage. [Wet or soft areas are not considered as uncontrolled seepage, but can lead to this type of deficiency. These areas should monitored my frequently.]

2. Displacement of the Embankment a. Displacement of the embankment is large scale movement of part of the dam. Common

signs of displacement are cracks, scraps, bulges, depressions, sinkholes and slides. 3. Blockage of Control Features

a. Blockage of Control Features is the restriction of flow at spillways, decant or pipe spillways, or drains.

4. Erosion a. Erosion is the gradual movement of surface material by water, wind or ice. Erosion is

considered a deficiency when it is more than a minor routine maintenance item. 2.2 Fly Ash Pond Complex The fly ash pond complex is comprised of diked embankments on the north, southeast, and south sides. County Road 273 runs along the toe of the north dike, a Plant haul road run along the top of the north dike, and a coal haul road runs along the crest or exterior of the Southeast dike. The northwest side of the Ash Pond Complex is located adjacent to a closed landfill area. There are three main ponds within the Ash Pond Complex as listed below. List of Main Ponds within the Ash Pond Complex Fly Ash Pond Bottom Ash Pond Clearwater Pond The Fly Ash Pond has internal splitter dikes that divide it into areas referred to as Ponds 1, 2, 3, and 4. The Bottom Ash Pond has an internal splitter dike creating the Bottom Ash Pond and Pond 5. Water enters the Ash Pond complex through either the Bottom Ash Pond or Pond 1. From the Bottom Ash Pond or Pond 1 water flows through the Ash Pond Complex in order from Pond 2, Pond 3, Pond 4, and Pond 5 before reaching the Clearwater Pond where it is discharged to the Holding Pond.

The Inspection included the Dike for the Metals Waste Cleaning tank as it is adjacent to the South dike of the Ash Pond complex

3.0 Review of Available Information (257.83(b)(1)(i)) A review of available information regarding the status and condition of the Ash Pond Complex, which include files available in the operating record, such as design and construction information, previous periodic structural stability assessments, previous 7 day inspection reports, and previous annual inspections has been conducted. Based on the review of the data there were no signs of actual or potential structural weakness or adverse conditions.

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4.0 Inspection (257.83(b) (1)(ii))

4.1 Metals Cleaning Waste Tank Dike (Non-CCR) A visual inspection of the dike for Metals Cleaning Waste Tank was conducted to identify any signs of distress or malfunction of the secondary containment system. Overall the facility is in good condition. The secondary containment is functioning as intended with no signs of potential structural weakness or conditions which would be disruptive to the safe operation of the containment system. Inspection photos are included in Appendix A. Additional pictures taken during the inspection can be made available upon request. Figures of the Metals Cleaning Waste Tank are included in Appendix B.

4.2 Ash Pond Complex

4.2.1 Changes in geometry since last inspection (257.83(b)(2)(i)) No modifications have been made to the exterior geometry of the Ash Pond Complex since the 2016 annual inspection.

4.2.2 Instrumentation (257.83(b)(2)(ii)) The location and type of instrumentation is shown on Figure 7 in Appendix B. The maximum recorded readings of each instrument since the previous annual inspection is shown in Table 1 below.

Table 1 – INSTRUMENTATION DATA Ash Pond Complex

Instrument Type Maximum Reading since last annual inspection

Date of reading

B7 Piezometer 724.72 7/18/2017 P-11 Piezometer 728.98 7/18/2017 P-12 Piezometer 747.70 10/10/2017 P-13 Piezometer 750.37 1/31/2017 B-0901 Piezometer 728.95 7/18/2017 B-0902 Piezometer 755.90 10/10/2017 B-0903 Piezometer 745.68 11/7/2016 B-0904 Piezometer 743.42 1/31/2017

Piezometers readings were generally consistent since the last inspection with the exception of B-7, B0901 and P-0902 that exhibit a slight upward trend. Piezometer well hydrographs are included in Attachment C.

4.2.3 Impoundment Characteristics (257.83(b)(2)(iii, iv, v)) Table 2 is a summary of the minimum, maximum, and present depth and elevation of the impounded water & CCR based on the bathymetric survey conducted May 18, 2017; the storage capacity of the impounding structure at the time of the bathymetric survey; and the approximate volume of the impounded water and CCR at the time of the bathymetric survey.

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Table 2 – IMPOUNDMENT CHARACTERISTIC DATA Impoundment Characteristics Ash Pond Complex Approximate Minimum depth of impounded water <1-ft Approximate Maximum depth of impounded water ~16.5-ft Approximate Present depth of impounded water ~10 ft (avg) Approximate Minimum depth of CCR ~11.5-ft Approximate Maximum depth of CCR ~18.3-ft Approximate Present depth of CCR ~15-ft (avg) Storage Capacity of impounding structure at the time of the inspection 2,500 ac-ft. Approximate volume of impounded water ~600 ac-ft. Approximate volume of CCR 1,000 ac-ft

Notes: 1. Water and CCR elevations vary across the Ash Pond Complex 2. Values based on observations, bottom elevation of 730, max. operating pool of 762

4.2.4 Visual inspection (257.83(b)(2)(i)) A visual inspection of the Ash Pond Complex was conducted to identify any signs of distress or malfunction of the impoundment and appurtenant structures. The inspection also included hydraulic structures underlying the base of the dike. Specific items inspected included all structural elements of the dam such as inboard and outboard slopes, crest, and toe; as well as appurtenances such as the outlet structure at the Bottom Ash Pond and Clearwater Pond, and pipe discharge structure.

Overall the facility is in good condition. The impoundment is functioning as intended with no signs of potential structural weakness or conditions which are disrupting to the safe operation of the impoundment. Inspection photos are included in Appendix A. Additional pictures taken during the inspection can be made available upon request. Figures of the Ash Pond Complex are included in Appendix B.

1) The outboard slopes, crest and inboard slopes of the embankments were generally in good condition. The embankments did not show any signs of structural weakness or instability. The vegetation along the embankments was well established. The crest did not contain any ruts or other signs of instability (Photo Nos. 1 to 7).

2) A chain link fence with gated access was constructed around the crest of the pond complex in compliance with North American Electric Reliability Corporation Critical Infrastructure Protection (NERC-CIP) program (Photo 8).

3) The interior cohesive soil slope of Pond 5 has experienced significant wave cut erosion (Photo 8).

4) There is minor seepage noted within the groin ditch along the exterior coal haul road

embankment but its origin cannot be readily ascertained due to vegetation (Photo Nos.9 and 10).

5) The drainage inlets and pipes along the coal haul road that collect storm water off the road are

in fair condition (Photo 11). 6) Construct similar drainage inlets and pipes along the ash haul road to collect storm water and

discharge it into the ash pond. Repair the existing slope where gulley erosion has occurred (Photo 12).

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7) Storm water sheet flow on the ash haul road shows rill erosion along the edge of the road and

has concentrated flow down the interior slope where gulley erosion has occurred (Photo 12). 8) Regrade slope within Pond 3 where surface drainage has created gulley erosion and create a

swale/(rip rap) ditch to convey storm water into the pond within this area (Photo 13). 9) The abandoned culverts under the coal haul road were in fair condition and showed no signs of

seepage (Photo 14).

4.2.5 Changes that effect stability or operation (257.83(b)(2)(vii)) Based on interviews with plant personnel and field observations there were no changes to the Ash Pond Complex since the last annual inspection that would affect the stability or operation of the impounding structure.

5.0 Summary of Findings

5.1 General Observations The following general observations were identified during the visual inspection:

Metals Cleaning Waste Tank Dike

1) The outboard slopes, crest and inboard slopes of the embankment were generally in good condition. The embankments did not show any signs of structural weakness or instability. The vegetation along the embankments was well established.

Ash Pond Complex

2) The outboard slopes, crest and inboard slopes of the embankments were generally in good condition. The embankments did not show any signs of structural weakness or instability. The vegetation along the embankments was well established. The crest did not contain any ruts or other signs of instability.

3) A chain link fence with gated access was constructed around the crest of the pond complex in compliance with North American Electric Reliability Corporation Critical Infrastructure Protection (NERC-CIP) program.

4) The Clearwater Pond hydraulic structure is in good condition. There were no signs of deterioration of the concrete or steel structures. The maximum pool elevation (762 ft. msl) is also clearly marked on the structure. Stop logs were available for use. Flow within the discharge pipe appeared unobstructed.

5.2 Maintenance Items The following maintenance items were identified during the visual inspection, see inspection map for locations:


1) No specific items identified related to the Metals Cleaning Waste Tank Dike.

Ash Pond Complex

2) Repair the interior cohesive soil slope of Pond 5 that has experienced wave cut erosion. The

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cohesive soil layer should be restored back to its original thickness and design slope and should also be overlain with geotextile and rip rap to minimize future erosion.

3) Continue to clear the vegetation on the exterior embankment along the Coal Haul road to the toe of the embankment and groin ditch plus a minimum of 20 ft. along the opposite slope and ascertain the origin of the seepage observed within this area.

4) Repair the drainage inlets and pipes along the coal haul road that collect storm water off the

road and discharge it downslope into the ash pond. Construct similar drainage inlets and pipes along the ash haul road to collect storm water and discharge it into the ash pond. Repair the existing slope where gulley erosion has occurred.

5) Regrade slope within Pond 3 where surface drainage has created gulley erosion and create a

swale/(rip rap) ditch to convey storm water into the pond.

5.3 Items to Monitor The following items were identified during the visual inspection as items to be monitored, see inspection map for locations:


1) No specific items identified related to the Metals Cleaning Waste Tank Dike.

Ash Pond Complex

2) The abandoned culverts under original coal haul road need to be inspected quarterly for seepage (Photo 14).

3) Continue to monitor for areas of erosion and repair as necessary.

5.4 Deficiencies (257.83(b)(2)(vi)) There were no signs of structural weakness or disruptive conditions that were observed at the time of the inspection that would require additional investigation or remedial action. There were no deficiencies noted during this inspection or any of the periodic 7-day or 30-day inspections. A deficiency is defined as either 1) uncontrolled seepage, 2) displacement of the embankment, 3) blockage of control features, or 4) erosion, more than minor maintenance. If any of these conditions occur before the next annual inspection contact AEP Geotechnical Engineering immediately

Appendix A

2017 DAM AND DIKE INSPECTION

CONESVILLE PLANT

METALS CLEANING WASTE TANK DIKE AND ASH POND COMPLEX

INSPECTION PHOTOGRAPHS

Appendix A, Conesville Metals Cleaning Waste Tank (MCWT) Dike and Ash Pond Complex Inspection Photographs Photographs taken on October 23, 2017

C:\Users\s201706\Desktop\Appendix A.docx Page 1 of 7

Photograph No. 1 Typical condition showing discharge of bottom ash into channel showing good conditions. Discharge area is armored with fabriform channel lining and rock gabion structures.

Photograph No. 2 Typical condition showing crest and exterior south perimeter embankment showing good vegetative cover and maintenance.



Photograph No. 3 Typical condition showing splitter dike crest between Pond 5 and the Clearwater pond. The interior Clearwater embankment shows good vegetative cover and maintenance.

Photograph No. 4 Typical condition showing exterior Clearwater embankment and discharge showing recent removal of woody vegetation. It is recommended that the area be seeded to prevent inadvertent erosion within this area.



Photograph No. 5 Typical condition showing the interior pond 4 embankment along the coal haul road exhibiting good vegetative cover and maintenance.

Photograph No. 6 Typical condition showing the exterior pond 3 embankment along the County Road 271 exhibiting good vegetative cover and maintenance. The toe ditch has been cleared of cattails and is free draining.



Photograph No. 7 Typical example of the chain link fence installed in 2017 around the fly ash pond to limit access to the pond. Note the locked condition on gate in conformance with NERC-CIP requirements.

Photograph No. 8 The clay liner requires repair to its original thickness and design slope with the addition of shoreline protection to prevent future wave cut erosion.



Photograph No. 9 Typical condition showing excessive vegetation along the exterior coal haul embankment and groin ditch.

Photograph No. 10 Upon removal of excessive vegetation, the origin of the seepage should be ascertained to determine if it is naturally occurring (ie. acid mine drainage) or if it originates from the pond complex.



Photograph No. 11 Typical view showing good condition showing storm water collection inlet and discharge pipe along the coal haul road.

Photograph No. 12 Additional storm water collection and discharge pipes should be installed along the fly ash haul road to mitigate erosion.



Photograph No. 13 Typical view showing erosion of the interior embankment within pond 3. The area should be regraded and ditched to convey storm water into the pond to mitigate erosion.

Photograph No. 14 Tyical view of corrugated metal pipes that extend through the embankment. The upstream end was sealed with a concrete wall. The pipes are part of the original construction in the 1950’s and should be monitored for seepage. Note: No seepage was observed during his year’s inspection.

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ATTACHMENT B

Inspection / Instrumentation Location Maps

Ash Pond System

Village of ConesvilleAEP ConesvillePlant Location

City of Coshocton

FIGURE

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SITE LOCATION MAP

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AEP CONESVILLE GENERATING PLANT - ASH POND SYSTEM47201 COUNTY ROAD 273

CONESVILLE, OHIO!

!

City of Coshocton

City of Columbus

SITE LOCATION

CoshoctonCounty

Sources:7.5 minute topographic quadranglesCoshocton, 1985Randle, 1978Conesville, 1978Wills Creek, 1986

s145543

s145543

American Electric Power

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Figure 2

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748.65

808.80

104

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IMAGERY DATE: MARCH 2006

UNIT: U.S. SURVEY FEET

ZONE: OHIO NORTHERN

DATUM: NORTH AMERICAN DATUM OF 1983 (NAD83)

HORIZONTAL CONTROL:

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DATE:

SCALE:1"=400'

DRN BY:AG

1 RIVERSIDE PLAZA

COLUMBUS, OH 43215

AEP SERVICE CORP.

DWG NO:FIGURE 3CONESVILLE POWER STATION

INSTRUMENTATION PLAN

ASH POND COMPLEX

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FIGURE 4 - INSTRUMENTATION DATA.

FAP CWP B-7 P-11 P-12 P-13 B-0901 B-0902 B-0903 B-0904 BAP

ATTACHMENT C

Instrumentation Data

Dates BAP FAP CWP B-7 B-11 B-12 B-13 B-0901 B-0902 B-0903 B-0904

3/9/2009 754.2 758.4 752.94 724.67 726.78 747.75 749.80 NR NR NR NR

6/30/2009 754.7 758.0 753.48 724.67 726.78 747.75 749.80 725.79 NR 724.47 742.80

9/28/2009 755.0 757.9 753.45 722.43 724.87 745.55 749.80 725.23 760.07 724.39 743.02

12/31/2009 757.2 758.1 753.92 724.32 726.18 746.17 749.77 727.15 759.63 NR 743.02

3/31/2010 758.0 758.1 753.98 728.48 730.52 747.19 749.82 730.95 760.92 748.02 743.15

6/21/2010 756.8 757.1 753.86 726.9 728.59 748.03 749.77 729.19 759.64 744.04 743.19

9/29/2010 753.9 757.3 752.554 722.65 725.17 746.42 749.73 726.18 755.18 729.68 742.91

12/31/2010 755.6 757.9 754.18 723.79 726.1 747.53 750.22 727.28 755.98 744.12 743.10

3/31/2011 754.9 757.4 753.89 730.13 732.1 748.96 749.70 732.06 757.27 746.81 743.26

6/29/2011 757.7 758.0 754.48 725.73 728.13 750.35 749.73 728.87 756.83 747.67 743.37

9/29/2011 755.7 758.1 753.94 723.02 725.57 750.11 749.72 726.77 756.09 747.88 743.52

12/22/2011 753.7 757.9 753.2 728.13 730.25 749.72 749.77 731.39 757.24 747.72 743.65

3/29/2012 754.3 758.0 753.19 725.49 727.62 749.85 749.76 728.73 756.85 747.84 743.46

6/29/2012 757.4 758.1 753.65 722.16 725.07 750.57 749.76 726.01 755.98 748.63 743.47

9/20/2012 NF 758.7 752.63 722.31 725.19 749.30 749.79 726.64 756.32 747.28 743.40

12/5/2012 NF 757.4 752.63 722.5 725.44 748.61 749.77 725.79 755.62 746.86 743.52

3/12/2013 NF 756.9 752.52 724.49 727.29 748.84 749.21 728.43 756.22 747.00 743.38

6/5/2013 NF 757.3 752.63 722.36 724.97 749.49 744.62 726.58 756.76 747.45 743.37

12/19/2013 NF 758.0 752.74 722.2 726.19 748.84 750.07 728.15 756.63 747.00 743.99

3/24/2014 NF 758.5 752.08 724.67 728.37 748.65 749.72 728.93 757.24 746.10 743.34

6/5/2014 NF 757.1 753.14 725.2 727.65 749.45 749.79 728.43 756.44 746.75 743.37

9/3/2014 NF 757.5 753.24 723.9 725.57 748.75 748.92 727.93 755.14 747.10 743.07

3/9/2015 754.6 757.8 753.04 720.9 725.57 749.85 748.92 726.88 754.99 749.60 743.07

6/18/2015 754.6 757.1 752.64 720.02 725.69 750.14 749.64 727.50 755.23 747.54 743.39

9/24/2015 754.6 757.5 754.14 725.23 749.71 749.77 726.19 754.46 747.15 743.58

11/12/2015 753.04 720.57 725.16 749.91 750.01 726.09 754.50 747.17 743.61

12/10/2015 753.4 753.54 722.04 729.24 747.60 749.78 729.54 755.19 743.69 744.12

1/7/2016 754.54 722.95 726.09 747.44 750.58 728.73 755.30 745.01 743.32

2/4/2016 754.64 722.61 725.86 747.25 750.10 727.08 754.83 744.44 743.27

3/3/2016 753.7 753.54 722.04 729.24 747.60 749.78 729.54 755.19 743.69 744.12

3/31/2016 722.35 728.32 747.55 750.47 728.18 755.54 744.35 743.37

4/28/2016 757.5 753.94 736.64 725.62 747.49 749.80 728.47 755.14 743.89 743.22

5/26/2016 757.8 754.4 723.93 727.13 747.63 750.27 727.96 755.79 744.78 743.20

6/23/2016 757.9 754.74 723.13 725.39 748.13 749.77 727.79 755.64 744.25 743.13

7/21/2016 757.9 754.74 721.18 725.10 747.69 749.81 725.81 755.47 744.65 743.19

8/18/2016 759.0 754.6 722.04 725.21 748.29 749.80 725.99 756.19 745.64 743.41

9/12/2016 758.0 753.5 722.98 725.04 747.85 749.72 727.78 755.79 744.82 743.18

10/10/2016 757.7 752.5 722.65 725.02 747.70 749.08 727.61 755.90 744.79 743.13

11/7/2016 756.6 753.2 721.83 725.08 747.01 749.36 725.92 754.81 745.68 743.01

12/5/2016 755.3 756.8 753.9 722.17 725.32 745.67 749.81 726.18 754.96 742.10 742.81

1/3/2017 758.2 757.8 754.24 722.76 725.58 745.81 749.86 726.42 755.27 742.48 743.22

1/31/2017 758.1 757.8 754.04 723.11 726.43 746.37 750.37 726.72 755.88 742.66 743.42

2/28/2017 758.1 757.8 754.14 723.56 726.67 746.27 749.23 727.55 755.47 744.16 743.04

3/28/2017 754.9 757.5 753.7 723.7 726.75 746.35 749.81 727.17 755.11 744.28 743.04

4/25/2017 754.9 757.4 753.5 724.7 727.76 746.35 749.83 727.95 755.11 743.62 742.99

5/23/2017 755.3 757.8 754.1 724.64 727.63 746.22 749.82 727.25 755.11 744.08 742.91

6/20/2017 755.3 757.8 753.9 724.1 726.37 745.77 749.80 725.45 755.04 743.40 742.82

7/18/2017 755.3 757.8 754.1 724.72 728.98 745.99 749.84 728.95 755.38 743.32 742.85

8/15/2017 755.3 757.8 754.1 724.64 728.76 745.92 749.80 728.80 755.50 742.89 742.78

9/12/2017 755.3 754.1 757.7 722.04 725.12 745.59 749.80 726.02 755.45 743.47 742.78

10/10/2017 754.1 755.3 757.7 722.01 725.03 745.31 749.76 725.94 755.47 742.47 742.87

Max Value

since Oct

2016

758.2 757.8 757.7 724.72 728.98 747.70 750.37 728.95 755.9 745.68 743.42

NF - No Flow

Table C1- Summary of Instrumentation Data.

DR - Destroyed

ND - No data

NR - No Reading

DM - Damaged

2017 annual dam and dike inspection report · 10/18/2001 · this document also uses the...

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