Design and Installation of Kamloops March 12, 2002 ......Design and Installation of Embedded Culverts Kamloops, March 12, 2002 Culvert Terminology 3 Slope/Gradient Barrel Invert Perching

1

Design and

Installation of

Embedded Culverts

Kamloops

March 12, 2002

Pilot 2

Part 2: Design

Kamloops, March 12, 2002Design and Installation of Embedded Culverts

2

Part 2: Design

6 Main Topics

1. Evaluation of site suitability

2. Detailed streambed profile

3. Sizing the pipe

4. Design embedment

5. Embedment material

6. Design drawings


3Culvert Terminology

Slope/Gradient

Barrel

Invert

Perching

Jump/Rest Pool

Weir


4

1. Evaluation of Site Suitability

• Fish stream

• Stable stream channel

• Stream gradient <6%

• Stream channel width

<2.5m

• Depth of excavatable fill

• Suitable for both stream

and road geometry

• Evaluate diversion options

Should consider the following:


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2. Detailed Streambed Profile

• Use precise instruments

• Establish elevation benchmarks


6Detailed Streambed Profile

• Horizontal

reference

stakes

Field Survey Reference Control

• Elevational

benchmarks

Spike BM in

blazed tree


7

• Extended distance upstream and downstream (~50m minimum)

• note potential influences such as log/debris jams, bedrock, nick points

Profile Length

Detailed Streambed Profile


8

96.5

97

97.5

98

98.5

99

99.5

100

100.5

101

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Elevation (m)

Length (m)

96.5

97

97.5

98

98.5

99

99.5

100

100.5

101

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Proposed

Stream Bed

Slope and

Elevation (at

low points)

Existing Stream Bed

Profile

Detailed Streambed Profile


9

• Culvert diameter / span must span SCW at point of embedment

Stream Channel Width

Edges of rooted

vegetation

Definite change in

vegetation and sediment

texture

3. Sizing the Pipe


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• Determination of Stream Channel Width with field measurements

• Use systematic approach to avoid skewing the results

(FSCG - 6 equally spaced intervals along 100 m length)

Diameter/Span

Sizing the Pipe


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• Round pipes - 40% of diameter or 0.6m,

whichever is greater

• Pipe-arch - 20% of vertical rise of the arch

Depth of Embedment

Sizing the Pipe


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• 40% of diameter or

0.6m, whichever is

greater

• Span the stream

channel width (SCW) at

embedment depth

present water level

Pipe Dia > Stream channel width

40% embeddment

Round Pipes

Sizing the Pipe


13

• Pipe-arch – 20% of

vertical rise of the

arch

• Span the stream channel width (SCW) at embedment depth

Present water level

Arch Span > Stream channel width

20% embedment

Arch Pipes

Sizing the Pipe


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• Check that Q100 will pass @ embedment depth

Check Q100

• Round pipe at 40% embedment => loss of 37% of area

• Arch pipe at 20% embedment => loss of 17% of area

Non-embedded pipe

Culvert Cross Sectional Area ~ 3 x Visible Highwater Area

Sizing the Pipe


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• Round pipe at 40% embedment -> loss of 37% of area

Check Q100

Round Culvert X-sectional

Area Required ~ 1.37 x

(3 x visible high water

area)

• Arch pipe at 20% embedment -> loss of 17% of area

Arch Culvert X-sectional

Area Required ~ 1.2 x

(3 x visible high water

area)

Sizing the Pipe


16

–Require P.Eng. For :

>2000mm

or >6 m3/s

FPC Forest Road Regulations

Sizing the Pipe


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• Depth of fill and fill slopes

• Road surface width

• Culvert gradient

• Skew angle of culvert to road

Factors Influencing

Culvert Length

Sizing the Pipe


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Factors Influencing

Culvert Length

• Include:

depth of fill

R/W width

gradient

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1.51

Sizing the Pipe


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• Include:

amount of skew to road r/w

C/L

Factors Influencing

Culvert Length

Sizing the Pipe


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4. Design Embedment

• Round pipes - 40% of diameter or 0.6m,

whichever is greater

• Pipe-arch - 20% of vertical rise of the arch

Depth of Embedment


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96.5

97

97.5

98

98.5

99

99.5

100

100.5

101

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Elevation (m)

Length (m)

96.5

97

97.5

98

98.5

99

99.5

100

100.5

101

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Proposed

Stream Bed

Slope and

Elevation (at

low points)

40% or 20 %

Embedment

Estimated

Culvert Invert

Elevation &

Slope

Existing Stream Bed

Profile

Design Embedment


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• Objective is to emulate/simulate natural streambed

• Fish passage is related to “Hydraulic Roughness” (HR)

• HR related to size of bed materials

• Bed materials, in turn, are related to water velocities and water depth in culvert which influence fish passage

5. Embedment Materials


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0

0.4

0.8

1.2

1.6

2

0 0.1 0.2 0.3 0.4 0.5 0.6

Depth of Flow (m)

Velo

cit

y (

m/s

)

5 cm

15 cm

30 cm

60 cm

Material Size

Material Size Influence on Velocity

Embedment Materials


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Velocity Refuge (Shadows)

Roughness reduces velocity and creates shadows

Embedment Materials


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Embedded pipes -modeling/simulating

the natural streambed

Embedment Materials


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• Size similar to that found in adjacent

natural streambed

Natural Stream Channel Embedment Material

“Rule of Thumb”

Embedment Materials


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• Design should specify composition and distribution sizes of material to be used

Range of Material Size

Embedment Materials


28Embedment Materials

• A range of substrate sizes (gradation) should be specified in the design

• Materials must be well graded to “seal” the streambed

• Ensure sufficient fines (sands & gravels) to “seal” the streambed

• Supplement with larger D90 material to help retain substrate

• D90 or greater particularly important on stream between 3 and 6%


Defn. D90 is the size of which 90% of the material will be smaller than


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35%

15%25%

25%

Cobble Gravel Fine Boulder

General Size Distribution of Embedded Material

Embedment Materials


Rule of thumb - aka George Robison


30Embedment Materials

Substrate Volume Determination

• Round pipe embedded 40% ~ 37% of area

Area(Round) = p(Dia/2)2

• Arch pipe embedded 20% ~ 17% of area

Area(Arch) from manufacturer info


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Design Drawings

Purpose

• Tools to “design” culvert to fit site

• Document proposed works and final product

• Provides material and construction specifications

• Provide construction referencing


32Design Drawings

Site Plan / Profiles

- Plan/profiles

developed for the

crossing

- design drawings

developed from site

plan / profiles

- used for design and

documentation

purposes


33Design Drawings

Site Plan

- contour map

of the site


34Design Drawings

Fit Crossing to Site

- The selected crossing

structure should be

suited to both the stream

and road

- consider road drainage

to minimize potential

sediment delivery to the

stream

- avoid vertical dips,

provide for roadway

drainage


35Design Drawings

Culvert

Profile


36Design Drawings

Road profile


37Design Drawings

Plan Drawing


38Design Drawings

Riprap Specifications


39Design Drawings

Installation Measures


40Design Drawings

Installation Referencing


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Other Details ie. Weir Design

• A downstream weir may

required as part of the

design to be installed

within 1.5 – 2 channel

widths downstream of

culvert outlet

• Assists in maintaining

adequate low flow depth

• Helps retain substrate

• Prevents formation of

plunge pool

• Particularly important

where stream gradient is >

3%

1.5 – 2 channel

widths

stream bank

stream bank

well graded boulders,

cobbles and fines leaving

no gaps in matrix

Design Drawings


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Plan View

Weir

Flow

Longitudinal View

WeirWeir Design

Design Drawings


43Design Drawings

Weir Design


44Design Drawings Summary

• Stream data

• Plan

• Profile

• Construction referencing

(vertical / horizontal)

• Materials specifications

• Installation specifications

• other details (riprap, weir, etc.)

Design should include:

Documents

Design and Installation of Kamloops March 12, 2002 ......Design and Installation of Embedded Culverts Kamloops, March 12, 2002 Culvert Terminology 3 Slope/Gradient Barrel Invert Perching