Guiding Landowners in Stream Restoration. The Science, Practice & Art of Restoring Native Ecosystems 2015

Transcription

1 Guiding Landowners in Stream Restoration The Science, Practice & Art of Restoring Native Ecosystems 2015 January 24, 2015

2 Guiding Landowners in Stream Restoration January 24, 2015

3 Agenda 1Watershed Planning 2Assessment 3Project Planning 4Applications

4 Stream Restoration Master Plans

5 Stream Restoration Master Planning Geomorphic assessment (departure analysis) Stream potential (valley type, geology, soils, land use, materials, constraints) Planform Diverse bedform topography Floodplain connectivity wet landscape

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7 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

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

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

10 Interpreting Depositional Features B1, B2 Stable B4, B8 Mod. Unstable B3 Unstable B5, B6, B7 Highly Unstable

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

12 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 >20% change in bankfull discharge >30% riffle embeddedness >20% pool filling with fine sediment

13 Detrimental riparian actions Pesticides, herbicides, salt Rock dams Yard waste disposal on top of banks Altered riparian vegetation especially mowed turf Broken concrete, riprap Wood removal Water gardening

14 When do you need assistance? Bank heights exceed 3-6 ft 6 ft banks = geotechnical concerns Replacing culverts or other structures Erosion threatens infrastructure Permitting assistance Channel instability Needs more than a change in management practices

15 Riparian Landowner DIY Vegetation Management Reducing the Width-to-Depth Ratio (with appropriate permits) Soil Bioengineering

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

17 Cost Reduction Avoid importing rock Use on-site materials: wood, gravel, topsoil Design and install appropriate erosion control products Design/Build? Construction bid as time and materials? Finish with volunteers (plants, blankets)

18 Actions Requiring Heavy Equipment Floodplain or riparian wetland restoration Toe wood construction Native vegetation transplants: shrub or sod Infiltration practices

19 Project Implementation Time scale Consequences of Do Nothing Fiscal or physical site constraints

20 Level of action required 1. Protection and conservation 2. Riparian management 3. Induced meandering or other adaptive management approach 4. Active restoration (or combined approach)

21 Self-Forming Channel Dam removal Master Plan Cost savings Grant eligible

22 Multi-phased restoration plan Cost savings Leverage infrastructure expenses Maintenance to a restoration approach Various restoration approaches - stream types vary by site constraints

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24 Induced Meandering

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26 Oxbow Re-Connection

27 Paint Creek Toe Wood Structure Log Vanes

28 Paint Creek Gravel Inner Berm Toe Wood Fabric-encapsulated Lift

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30 Paint Creek Children s Park Concept Plan

31 Paint Creek Meeks Park Concept Plan

32 Paint Creek Master Plan White topping asphalt to reduce thermal impacts Bioretention and detention basin retrofits Catchbasin and outfall retrofits Sidewalk removal/raised boardwalk and floodplain connectivity Replace bridge to allow floodplain connectivity Manage and restore riparian vegetation to maintain views, angler access, shade, stability Channel re-meandering to maintain pools, toe wood, gravel augmentation, riffle/glide/pool construction

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34 Typical Channelized Stream

35 Floodplain Connectivity Restored

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37 Multi-Stage Channel Design Technical guidelines for open drain design in Macomb County Funded by MI Sea Grant Partnering with WSU Website:

38 Riparian Vegetation Management 0% Canopy 100% Canopy No canopy Cattails/phragmites Siltation, flooding Fully shaded Invasive shrubs Bare banks underneath The Goal 50-75% Canopy

39 Riparian Improvement Cut Clearing and thinning Cut and treat invasives Reuse materials (mulch, LWM) Establish plantings with vertical diversity o Seed bare areas (native grasses) o Soil bioengineering (native shrubs) oshade trees above top of bank Perennial crop vegetated buffers?

40 Questions?