hydrology is the distribution and movement of water

Hydrology is the distribution and movement of water.

Stream Morphology is the form and structure of a stream (cross-section, sinuosity, profile).

“A river is the report card for its watershed.”

Alan Levere, CT DEP

Morphologic Stability means no net change in channel shape, which occurs only if channel-forming flows are stable.

Extreme flood flows generally have little effect on channel morphology because they are so rare. More frequent flows, those that recur about every 1 to 2 years, are generally the dominant channel-forming flows in stable, natural streams (Schueler, 1987 and Rosgen, 1996).

Morphologic Stability means no net change in channel shape, which occurs only if channel-forming flows are stable.

Hydrologic changes can cause a stream to be morphologically unstable for 60 years or more.

Physical indicator of unstable stream morphology: down-cut

A more typical down-cut.

Physical indicator of unstable stream morphology: extensive, excessive erosion, especially along straight reaches

Sometimes the problem is local and the cause obvious.

Sometimes the problem is natural.

• Characterize the watershed

• Understand stream flow impacts of hydrologic changes

• Provide a basis for stormwater management recommendations

• Help determine critical areas

Goals of Hydrologic Analysis for NPS Watershed Management Plans

Little P

ortag

e Lake

To

ma R

oad

Hi-L

and

Lake

Tip

lady R

oad

Halfm

oo

n to

W

oo

db

urn

Lakes

Un

adilla R

oad

Kan

e Ro

ad

M-52

William

sville to

Ellsw

orth

Lakes

McC

on

achie L

ake

Stream order provides an indication of stream size and potential power. 1st to 3rd order streams may be more sensitive to hydrologic changes.

Stream Order

Data courtesy of MDNR Institute for Fisheries Research and the USGS Great Lakes Gap

Conservation and

Recreation Lands

25% of watershed

Percent Imperviousness

Excerpted from “The Practice of Watershed Protection” by Thomas Schueler and Heather Holland, p. 15

Urban Stream Classification Sensitive* Impacted Non-supporting

Channel Stability Stable Unstable Highly unstable

Water Quality Good Fair Fair-Poor

Stream Biodiversity Good-Excellent Fair-Good Poor

Resource ObjectiveProtect biodiversity and channel stability

Maintain critical elements of stream quality

Minimize downstream pollutant loads

* The expected quality of streams in this range of impervious cover is generally influenced more by other watershed characteristics such as forest cover, road density, riparian continuity, and cropping practices.

Every Portage Creek subbasin is less than 5% impervious.

1800

1978 2000

Land Cover

Soils 1800

1978 2000

• Characterize the watershed

• Understand stream flow impacts of hydrologic changes

• Provide a basis for stormwater management recommendations

• Help determine critical areas

Goals of Hydrologic Analysis forNPS Watershed Management Plans

Subbasins

Subbasins

Non-contributing

Runoff from each subbasin for a standard storm is calculated to highlight subbasins that generate a higher proportion of runoff due to soils and land cover.

1800Land Cover

2000Land Cover

Runoff Volume per Area

1978Land Cover

Change: 1800 to

2005

Runoff Volume Change per Area

Yields are calculated as a measure of hydrologic responsiveness.

Flood Flow Yields

1800Land Cover

1978Land Cover

2000Land Cover

cfs/acre

Yields: Peak Flow per Area

1800 to 1978

1978 to 2000

Example of

land use change

and its effect

50 percent chance (2-year) flow

Pre-development Post-development

70% increase in peak flow,

170% increase in runoff volume,

former instantaneous peak flow now lasts ~4 hours

A stream described as flashy responds to rainfall by rising and falling quickly.

A stream that is not flashy would rise and fall less for an equivalent rainfall and would typically derive more of its overall flow from groundwater.

Flashiness Analysis

David Baker, Peter Richards, Timothy Loftus, and Jack Kramer (2004) proposed quantifying flashiness by measuring the path length of flow oscillations for data from gaged streams. Longer paths correlate with flashier streams, while more constant flows have shorter path lengths.

Watershed areas and total yearly flow volumes are similar.

0.56

0.05

04172500 Portage Creek at Tiplady near Pinckney

Total Drainage Area: 82 square miles First Water Year: 1945

Average R-B Index Value: 0.059 Last Water Year: 1971

Rank: lowest Number of Years Analyzed: 27

Trend: Not Applicable

Note: Flows are adjusted to an equivalent drainage area of 79 square miles.

Portage Creek at Tiplady

River Raisin near Manchester

Mill Creek near Dexter

Mill Creek near Lima Center

Saline River near Saline

Portage Creek at Tiplady

River Raisin near Manchester

Mill Creek near Dexter

Mill Creek near Lima Center

Saline River near Saline

Portage gage compared to 38 statewide gages with similar sized watersheds (80 to 100 sq. mi.).  The Portage gage is third lowest, sorted by 2-year peak flow or by 2-year peak flow divided by drainage area .

Station ID DA SQ MI QP 2.0 Peak/DA   Station ID DA SQ MI QP 2.0 Peak/DA

4135600 76 113 1.5   4175340 68 603 8.9

4160900 79 145 1.8   4102776 83 607 7.3

4172500 79 177 2.2   4108600 71 620 8.7

4097170 68 179 2.6   4112850 81 648 8.0

4143900 84 205 2.4   4148260 67 668 10.0

4096500 60 229 3.8   4127800 68 668 9.8

4161800 68 244 3.6   4102700 84 838 10.0

4122223 78 303 3.9   4057820 73 882 12.1

4131000 79 313 4.0   4054500 92 884 9.6

4124500 60 347 5.8   4167000 100 1100 11.0

4044724 81 374 4.6   4176400 95 1180 12.4

4127850 64 389 6.1   4096015 81 1200 14.8

4065393 62 393 6.3   4145500 89 1230 13.8

4129000 63 417 6.6   4164150 90 1250 13.9

4131500 88 432 4.9   4166100 88 1300 14.8

4041000 63 437 6.9   4168000 83 1330 16.0

4161540 71 447 6.3   4157500 67 1760 26.3

4138000 84 498 5.9   4108801 69 2190 31.7

4060500 92 498 5.4   4108800 66 2270 34.4

4148140 99 580 5.9          

• Characterize the watershed

• Understand stream flow impacts of hydrologic changes

• Provide a basis for stormwater management recommendations

• Help determine critical areas

Goals of Hydrologic Analysis forNPS Watershed Management Plans

Water quality, preventing stream channel erosion, and flood control are concerns of watershed planners and stakeholders. The rain events that produce these concerns overlap. In general, small storms, and runoff from the early part of larger storms, are the focus of water quality BMPs. Channel protection measures focus on larger, but still fairly common storm flows. Flood control is generally associated with infrequent events.

adapted from Sullivan, 2002

Water Quality (First Flush)

Channel Shape (Morphology)

Flooding

Interception, Evapotranspiration,

Infiltration

Precipitation

Small storms and the first part of the runoff from larger storms typically carry most of the pollutants to an urban stream.

First Flush Treatment

From Gun River Hydrologic and Hydraulic Study, Appendix 6Extended Detention

Low Impact Development (LID) LID integrates stormwater practices throughout the

site, preserves natural functions, and reduces impervious surfaces

•Bioretention/rain garden

•Grassed swale

•Green roofs

•Porous pavement

•Stormwater reuse

•Preservation of natural features

•Native plantings

East Hills Center Green RoofBazzani Associates

Porous Pavement

Pokagon Edewat subdivision

• Characterize the watershed

• Understand stream flow impacts of hydrologic changes

• Provide a basis for stormwater management recommendations

• Help determine critical areas

Goals of Hydrologic Analysis forNPS Watershed Management Plans

ID Subbasin

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Total Score

1 Portage Creek to mouth/Little Portage Lake outlet 5 0 5 3 0 3 0 16

2 Unnamed tributary to mouth/Little Portage Lake 10 3 5 10 2 3 0 33

3 Portage Creek to Tiplady Road, Gage #04172500 2 3 5 0 2 5 0 17

4 Portage Creek to Hi-Land Lake outlet in Hell 10 3 5 3 1 0 0 22

5 Unnamed tributary to Hi-land Lake 2 0 1 10 1 1 0 15

6 Portage Creek to Woodburn Lake 2 3 3 3 1 0 0 12

7 Livermore Creek to Woodburn Lake 2 5 3 0 4 0 0 14

8 Portage Creek to confluence with unnamed trib, in Unadilla 2 5 1 0 6 0 0 14

9 Unnamed tributary to mouth in Unadilla 5 3 3 0 1 1 0 13

10 Portage Creek to Williamsville Lake outlet 10 3 5 0 0 3 0 21

11 Stockbridge Drain to mouth at Williamsville Lake 5 5 1 0 6 0 0 17

12 Portage Creek to Ellsworth Lake 5 5 1 0 4 1 0 16

13 Unnamed tributary to Ellsworth Lake 5 5 5 3 2 3 0 23

14 Portage Creek to McConachie Lake outlet 2 5 0 0 4 1 0 12

15 Unnamed tributary to McConachie Lake 5 10 0 10 10 0 0 35

16 Portage Creek to unnamed tributary near Stockbridge 5 5 1 0 6 0 0 17

17 Unnamed tributary to mouth near Stockbridge 5 3 3 3 4 1 0 19

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