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

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

Fish Passage

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

Fish Passage Backwater from burial – Y up, V down

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

Fish Passage Velocity Distribution in Culverts

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

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

Fish Passage Substrate

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)

Fish Passage Yn - Class 1Mn - Class Substrate - Impact on Roughness

Fish Passage

Channel parameters: B = 3.0 m, h = 1.5 m, T = 7.0 m, S = 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 = m, S = For S = m/m, Y FPDD = 0.39 m, Q FPDD = 1.3 cms, V FPDD = 0.9 m/s

Fish Passage