Use of WARSSS in Stream Restoration and Watershed Planning. Michigan Aquatic Restoration Conference 2015

Transcription

1 Use of WARSSS in Stream Restoration and Watershed Planning Michigan Aquatic Restoration Conference 2015 October 22, 2015

2 Use of WARSSS in Stream Restoration and Watershed Planning 1. Watershed Management Planning 2. Catchment-Scale Restoration Management Plans 3. Clean Sediment, Biota, and D.O. TMDLs 4. Reach-Scale Stream Restoration Design 5. Habitat and Biological Monitoring

3 Watershed Assessment of River Stability and Sediment Supply Geomorphology-based framework for evaluating river stability Disproportionate sediment/tp supply Assess instability causes Prioritize restoration efforts Developed with the USEPA

4 Rosgen, 2014

5 Sediment Supply Clean sediments (i.e., non-toxic) Sediment-starved reaches Sources of disproportionately high sediment loads

6 Departure Analysis

7 Watershed Scale Source: Center for Watershed Protection

8 Belle River Watershed Plan

9 Belle River Longitudinal Profile Adapted from Knutilla, 1969

10 Streambank Erosion Screening Stream Types Bank Height Ratio (>1.5 = High/VH) Radius of Curvature-to-Width (<2.25) Altered Riparian Vegetation (mowed turf grass, bare soil, or tilled areas)

11 Watershed Planning: In-Stream Pollutants, Sources, and Causes Source: MDEQ, 2000

12 Impervious Cover Model Belle R. Source: Center for Watershed Protection

13 River Instability Processes Over-widening Accelerated downstream meander migration Chute cutoffs Aggradation (excessive deposition) Degradation (downcutting or incision)

14 Signs of Excess Deposition Pool filling Most of bed exposed during low flow Slope reversals Coarse over-bank deposition Transverse bars; mid-channel bars; side bars

15 Signs of Degradation Exposed till river bed Nickpoints caused by headcutting Stream tributary rejuvenation Steep bars Leaning trees, vertical banks

16 Geomorphic Thresholds Bank height exceeds1.3 x bankfull depth Width-to-Depth Ratio exceeds 1.4 x reference W:d Shift in stream type >25% of banks or vegetation impacted >30% riffle embeddedness >20% pool filling with fine sediment

17 Historic Aerials Time Trend

18 Look for man-made impacts Channelization, dredging, relocation Bed lowering at road crossings Dams, weirs, rock dams, in-line ponds Altered riparian vegetation; cattle Floodplain encroachment; riprap Wood removal; clearing and snagging Excess sediment supply, construction Gravel mining

19 (Rosgen, 2007)

20 Belle River ICD

21 Belle R. IC Drain Departure Analysis Parameter Measure Reference (Richmond Twp) Impaired (ICD) Lateral Stability Width-to - Depth Ratio 18.8 Stable 12.0 Stable Vertical Stability D84 (or Di bar) 2 in. Gravel Stable Silt/clay Aggrading Vegetation Class Tree/Shrub/ Grass Stable Turf Grass Not Functioning Floodplain Connectivity Bank Ht Ratio 1.0 Functioning 2.3 Channelized Entrenchment Ratio 7.9 Functioning 1.5 No Floodplain Hydraulics Gradient 0.112% Functioning % Not Functioning Shear Stress 0.22 lb/ft 2 Sediment Competence 0.08 lb/ft 2 Depositional

22 Deposition, Excessive Wood Removal

23 Natural 2-Stage Ditch Analog

24 Hillslope Failures

25 Natural Toe Wood Analog

26 Subwatershed Restoration Master Plans

27 Subwatershed Master Planning Communicate with multiple landowners Cost savings Leverage infrastructure expenses Various restoration approaches which vary by site constraints

28 Level of Action Required 1. Protection and conservation 2. Riparian management 3. Empirical (adaptive) management approach 4. Active restoration (or combined approach)

29 Phasing by Focus Area Infiltration, tile control structures Water on the landscape Fish passage: culvert replacement, weirs Sediment regime: gravel augmentation, excessive fines Cattle or human access points Floodplain excavation Tree planting Instream habitat: wood

30 TMDLs

31 Dissolved Oxygen TMDLs SOD; algae decomposition >>> anoxic Sulfide and ammonia toxicity Source: G Fred Lee

32 Reach-Scale Restoration

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35 Typical Channelized Stream

36 Floodplain Connectivity Restored

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38 Microhabitat-Scale Assessments Limiting Factor Analysis Assess specific facets (ex. pools) Interpret biomonitoring results

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40 Assessing Stream Functions Parameter Simple Measure Intensive Measure Floodplain connectivity Bank Height Ratio Entrenchment Ratio Stage vs. discharge Bedform diversity % Riffles and pools Max. pool depth Variable depth, velocity, Froude number Lateral stability Streambank erosion Replicate cross-sections Riparian vegetation Buffer density, width Vegetation plots Adapted from Harman, et al. 2012

41 Qualitative Habitat Assessment (ex. pools)

42 Ex. Quantitative Pool Assessment Pool type, pool dimensions, pool slope, point bar slope Pool Length to Riffle Width Dimensionless Ratios Pool Max. Depth to Riffle Mean Depth Pool Slope to Avg. Slope Lateral Scour Pool Mean Min. Max.

43 Interpreting Biomonitoring Results by Stream Type (Source: Friends of the Rouge, 2015)

44 Questions?