Culvert Hydraulics

• Hydrotechnical Design Parameters• Channel Hydraulics• Culvert Hydraulics• Culvert Sizing

Culvert Hydraulics

Hydrotechnical Design Parameters

Culvert Hydraulics

•Area•Shape•Slope•Storage•Density•Vegetation•Soil Type•Initial Moisture

Culvert Hydraulics

200100502010521.251.051.00310

100

1000

Return Period (Years)

Dis

char

ge (c

ms)

Data

GEV

LN3

LP3

Options - Statistics

200100502010521.251.051.003100

1000

10000

Return Period (Years)

Dis

char

ge (c

ms)

LN3 - Without Ungauged Data

LN3 - With Ungauged Data

Gauges >30 Years (212)

0

1

2

3

4

5

0 100 200 300

Discharge (m3/s)

Stag

e (m

)

Culvert Hydraulics

Options - Model

0

20

40

60

80

100

120

0 50 100 150 200

Rainfall (mm)Ru

noff

(mm

)

Foothills

Swan Hills

Western Plains

Central Plains

SE Corner

50

100

200

400

Culvert HydraulicsStream Location Year Flow (cms) Stage (m) Stream Location Year Flow (cms) Stage (m)Oldman Lethbridge 1995 4700 8.5 N. Sask. Edmonton 1899 6000 13.0

1908 4500 8.3 1915 5800 12.81948 3500 7.5 1986 4500 11.61953 3100 7.1 1952 3750 10.82013 2400 6.3 2013 2800 9.5

Bow Calgary 1879 2250 4.5 Athabasca Athabasca 1954 5700 7.11897 2250 4.5 1944 5000 6.82013 1700 4.1 1971 4600 6.51902 1550 4.0 1986 4500 6.51932 1500 4.0 1980 4300 6.3

Red Deer Red Deer 1915 1900 6.6 Smoky Watino 1990 9400 10.42005 1500 5.9 1982 9200 10.21954 1500 5.9 1972 9000 10.02013 1300 5.5 1987 7100 8.71952 1250 5.4 1965 5500 7.6

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Component Governs % System

Channel Capacity Most channels > 80%

Historic HWM Large streams ~ 10%

Runoff Potential Small basins < 5%

Hydrotechnical Design Guidelines

Culvert Hydraulics

Channel Capacity

Culvert HydraulicsHistoric Highwater - AT

Culvert Hydraulics

0

40

80

120

160

200

Jun/18 Jun/19 Jun/20 Jun/21 Jun/22 Jun/23 Jun/24

Disc

harg

e (c

ms)

Alberta 'd' vs 'Tc' Observations - Rainfall

0

50

100

150

200

250

0 20 40 60 80 100Time to Centroid Of Hydrograph 'Tc' (Hours)

Run

off D

epth

'd' (

mm

)

05A&11A05B - F07A07B - G

Basin Runoff Potential

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Channel Hydraulics

Culvert Hydraulics

S

1

Y

V = 14 Y0.67 S0.4

Normal Flow

Culvert Hydraulics

B

h

T

Q = AV

Culvert Hydraulics

Culvert Hydraulics

S

1

1. Normal2. RVF

3. GVF

Other Flow Profile Cases

Culvert Hydraulics

S

1

EGL• EGL flows downhill• Head loss at RVF

E = Y + V2/2g

Culvert Hydraulics

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Culvert Hydraulics

Bridge

Culvert

Culvert Hydraulics

Culvert Hydraulics

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

RVF - ExpansionRVF - Contraction

Barrel – GVF +

D/S Channel - Normal

U/S Channel - GVF

Trans - AdverseTrans - Steep

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Culvert Hydraulics

Culvert Sizing

Culvert HydraulicsSizing:• Complex – need model• Start :– Rise = burial + Y + headloss• Range - sizes, shapes, barrels, profiles• Parameters – V, freeboard/ponding• Practical – drift/ice, future lining

Culvert HydraulicsConsiderations:• Fish Passage• Blockage - Drift, Icing• End Protection Works (V)• Ponding:

- Upstream Flooding- Uplift Failure- Embankment Stability- Road Overtopping