Minnehaha Creek – Reach 14 Streambank Improvement Project

1. Minnehaha Creek – Reach 14Streambank Improvement Project

2. Design Concept 1 – From the Creek • Is this a “fun” stream to paddle? • The allure of a journey, what’s around the next bend? • Viewing wildlife • Viewing architecture • Hearing the sounds • Connecting with the water

3. Design Concept 1 – From the Creek

4. Is Natural Buffer Strong Enough? • Project feasibility study included hydraulic modeling • Average bankfull shear stress = 0.43 lb/ft2 • Max, 100 yr shear stress at France Ave. weir = 1.2 lb/ft2 By the numbers, in general nothing larger than 6” rock is required. Homeowner observations?

5. Design Concept 2 – From the Home Is this the “best” stream to live on? Different aesthetic preferences Neat & orderly Manicured Natural & organic • Different desires in ownership • Viewing wildlife • Viewing the stream • Hearing the sounds • Access to the water • Separation from neighbors

6. What Could It Look Like? Before After

7. Variable Site Conditions • Sun exposure (Full sun to full shade) • Slope • Existing rip rap (rock) or retaining wall • Variable water levels • Existing structure or gardens

8. Sun Exposure Full Sun to Full Shade – There are natives for that Images courtesy of Prairie Moon Nursery

9. Slope

10. Existing Turf Grass – Remove & Re-Vegetate with Native Buffer • Rely on the strength of the deep growing roots.

11. Existing Rip Rap – Cover w Soil & Re-Vegetate with Native Buffer Minneapolis Avenue Minnetrista, MN

12. Existing Rip Rap – Live Stake or Joint Planting

13. Existing Retaining Wall – Replace with Vegetated Rock Wall • Retaining walls offer no habitat • But retaining walls are usually installed for specific reasons • Hydraulic protection of bridges and culverts • Maximize real estate • Vegetated Rock Wall • Space between the stones provide edge habitat • Reduces the need to regrade the banks • Overhanging vegetation can reduce thermal loading of the stream • Reflective flow

14. Existing Retaining Wall – Replace with Vegetated Rock Wall

15. Existing Retaining Wall – Replace with ‘Terraced Pocket’ Boulder Wall

16. Variable Water Levels Excerpts from Shaw, D. and Schmidt, R. 2003, Plants for Stormwater Design

17. Work with Existing Structures & Gardens

18. Concept Plan

19. In Stream Habitat Improvements • Root Wads • Provide wood debris and cover • Protect the bank from erosion

20. In Stream Habitat Improvements • Vegetated Brush Mattress • Build up eroded areas by trapping sediment

21. In Stream Habitat Improvements • In-Stream Boulders • Provide small scour pools & current breaks

22. In Stream Habitat Improvements • Stream Barbs • Diverts flow from eroding banks • Capture sediment

23. In Stream Habitat Improvements • Coir Logs • Capture sediment during high water levels

24. Visit Wenck’s Similar Projects • Shingle Creek Drive & Hampshire Ave., Brooklyn Park, MN • Stabilize Shingle Creek streambanks, install native buffer and add in-stream habitat for an entire reach • 26th Ave & Sycamore Ln Plymouth, MN • Stabilize Plymouth Creek streambanks, install native buffer and add in-stream habitat for an entire reach • Minneapolis Ave & Crest Ridge Ct., Minnetrista, MN • Recreate a waterway out of an eroded gully that can handle urban runoff. • Example of vegetated riprap

25. Preparation for the Site Visit • Review your sun condition (sun, part sun or shade). • Review the seed list that matches your sun condition. • Review the plant list the matched your sun condition and select the one you think will complement the seed list and your landscaping. • Review the concept plan and make edits, write down your thoughts and be prepared to discuss.