1. River Ribble and River Brun River Restoration Audit and Options Appraisal Seb Bentley and George Heritage

2. 2 Overview Initial Audit Hydraulic modeling Discussion

3. BACKGROUND INITIAL AUDIT HYDRAULIC MODELING RESTORATION WORKS

4. BACKGROUND

5. Background The main river Ribble is 80 miles long, Starting near Ribble Head, flowing to Preston and the Irish Sea. Known for it’s assets but people, forget (sometimes intentionally) about the less exciting areas… URES came about following significant works to improve fish passage in the Calder, including the removal of Padiham and Montford weirs, and fish passes and easements at Barrowford. After achieving this, the next priority areas had to be identified and addressed through Burnley

6. Background - the problems Fast Flowing Narrow Man made Limited gravels Steep Poor habitat

7. Background – the opportunities! options in terms of making improvements for wildlife essential part of the project was that we did not impinge on the needs of people

8. Background Comprehensive study of Calder and Brun Restricted to maintaining a lined channel for channel stability, flood risk

9. APPROACH

10. Approach To restore some hydromorphic function and ecological habitat to the River Calder and River Brun To adjust the present engineering configuration helping to achieve the Water Framework Directive objectives for the failing rivers Stage one – A desk and field based hydromorphological audit Stage two – Options testing and hydraulic modelling

11. HYDROMORPHIC AUDIT AND ASSET SURVEY

12. Audit and survey

15. RESTORATION OPTIONS

16. Restoration options appraisal Current channel geometry

17. Restoration options appraisal Pool zones

18. Restoration options appraisal Riffle zone

19. Restoration options appraisal Point bar zone

20. Restoration options appraisal Apical pool zone

21. Restoration options appraisal Low flow riffle/rapid reach

22. Restoration options appraisal Backwater reach

23. HYDRAULIC MODELLING

24. Hydraulic modelling – Study Reaches

25. Hydraulic modelling – Proposals

26. Hydraulic modelling – 2D Backwater

27. Hydraulic modelling – 2D Pool

28. Hydraulic modelling – 2D Low Flow Riffles

29. Hydraulic modelling What does this mean in terms of sediment?

30. Hydraulic modelling What does this mean in terms of fish? Assumption – In water velocities >0.7m-1 fish will become tired. Fish 0.25m in length VelocityDistance travelled 0.5>100m 115m 1.57m 23m 2.5struggle

31. Hydraulic modelling 1 in 2yr –Velocities

32. Flood Risk Compared pre and post restoration scenarios using 1D-2D linked modelling.

33. Restored Reaches

34. .

35. Conclusions Difficult urban setting Needed to work with sediment dynamics and ecology Audit vital in understanding system Modelling provided confidence in restoration design Two winters suggests successful dynamic equilibrium