principle make culvert not a velocity barrier to fish
DESCRIPTION
Principle Make culvert NOT a velocity barrier to fish Compare to typical natural channel hydraulics Use V (section average) as indicator. Design Flow Parameters: Evaluate at Q > normal, Q < flood Choose Q fpd – only exceeded 5% of days Calculate hydraulically (no statistics). - PowerPoint PPT PresentationTRANSCRIPT
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 Qfpd – only exceeded 5% of days
• Calculate hydraulically (no statistics)
Fish Passage
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0.5
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0 10 20 30 40 50 60 70 80 90 100
% Time Flow Less Than
Q /
Q90
Rati
o
Fish Passage
YFPD = 0.8 – 34.3S ; min. YFPD = 0.2
Y98 envelope
Fish Passage
98.0
99.0
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105.0
020406080100120140160180200
Invert + Culvert
Energy Gradeline
Water Surface EL.
Top of Bank
Critical Depth
Normal Depth
Backwater from burial – Y up, V down
Fish Passage
98.0
99.0
100.0
101.0
102.0
103.0
104.0
105.0
020406080100120140160180200
Invert + Culvert
Energy Gradeline
Water Surface EL.
Top of Bank
Critical Depth
Normal Depth
Backwater from burial – Y up, V down
Backwater effect lost- V > Vch?
Fish PassageVelocity 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 PassageVelocity Reduction Options – NOT Effective• Increase Pipe Diameter - mostly air space
• Increase Burial – ineffective >1m, ponding, u/s barrier, excavation?
Fish Passage
Substrate
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-5 -4 -3 -2 -1 0 1 2 3 4 5
XS Station (m)
Elev
atio
n (m
)
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 > Vch (U/S)
Fish Passage
Y n - Class 1M n - Class 1
0.1 0.161 0.2 0.079 0.1410.3 0.064 0.0950.4 0.057 0.0790.5 0.053 0.0710.6 0.050 0.0650.7 0.048 0.0620.8 0.047 0.0590.9 0.046 0.0571.0 0.045 0.0551.1 0.044 0.0541.2 0.044 0.0531.3 0.043 0.0521.4 0.043 0.0511.5 0.042 0.050
Substrate - Impact on Roughness
Fish Passage
Fish Passage• Channel parameters: B = 3.0 m, h = 1.5 m, T = 7.0 m, S = 0.012 • Design flow parameters of Qdes= 36 cms, Ydes= 2.25 m, Vdes= 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, YFPDD = 0.39 m, QFPDD= 1.3 cms, VFPDD = 0.9 m/s
Fish Passage