1. Fish Passage Principle Make culvert NOT a velocity barrier to fish Compare to typical natural channel hydraulics Use V (section average) as indicator

2. Fish Passage Design Flow Parameters: Evaluate at Q > normal, Q < flood Choose Q fpd – only exceeded 5% of days Calculate hydraulically (no statistics)

3. Fish Passage

4. Y FPD = 0.8 – 34.3S ; min. Y FPD = 0.2 Y98 envelope

5. Fish Passage Backwater from burial – Y up, V down

6. Fish Passage Backwater from burial – Y up, V down Backwater effect lost - V > Vch?

7. Fish Passage Velocity Distribution in Culverts

8. Fish Passage Velocity Reduction Options - Effective Increase Pipe Roughness – long culverts, steep grades (normal flow) Use Multiple Pipes – wide, shallow channels; consider drift blockage Use Wider Shape (Box, Ellipse) – cost vs bridge

9. Fish Passage Velocity Reduction Options – NOT Effective Increase Pipe Diameter - mostly air space Increase Burial – ineffective >1m, ponding, u/s barrier, excavation?

10. Fish Passage Substrate

11. Fish Passage Substrate Holders: Ht. = 0.3m (0.2m for D<3m) Space = Ht / S (Min. 7m) Class 1M or 1 Rock Substrate Only where V > V ch (U/S)

12. Fish Passage Yn - Class 1Mn - Class 1 0.10.161 0.20.0790.141 0.30.0640.095 0.40.0570.079 0.50.0530.071 0.60.0500.065 0.70.0480.062 0.80.0470.059 0.90.0460.057 1.00.0450.055 1.10.0440.054 1.20.0440.053 1.30.0430.052 1.40.0430.051 1.50.0420.050 Substrate - Impact on Roughness

13. Fish Passage

14. Channel parameters: B = 3.0 m, h = 1.5 m, T = 7.0 m, S = 0.012 Design flow parameters of Q des = 36 cms, Y des = 2.25 m, V des = 2.8 m/s Culvert structure: D = 3670 mm, L = 86 m, Burial = 0.925 m, S = 0.012 For S = 0.012 m/m, Y FPDD = 0.39 m, Q FPDD = 1.3 cms, V FPDD = 0.9 m/s

15. Fish Passage