1 Design and Installation of Embedded Culverts Kamloops March 12, 2002 Pilot 2 Part 2: Design
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Design and
Installation of
Embedded Culverts
Kamloops
March 12, 2002
Pilot 2
Part 2: Design
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
3Culvert Terminology
Slope/Gradient
Barrel
Invert
Perching
Jump/Rest Pool
Weir
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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:
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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2. Detailed Streambed Profile
• Use precise instruments
• Establish elevation benchmarks
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
6Detailed Streambed Profile
• Horizontal
reference
stakes
Field Survey Reference Control
• Elevational
benchmarks
Spike BM in
blazed tree
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• Extended distance upstream and downstream (~50m minimum)
• note potential influences such as log/debris jams, bedrock, nick points
Profile Length
Detailed Streambed Profile
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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)
Existing Stream Bed
Profile
Detailed Streambed Profile
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• 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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• 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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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–Require P.Eng. For :
>2000mm
or >6 m3/s
FPC Forest Road Regulations
Sizing the Pipe
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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Factors Influencing
Culvert Length
• Include:
depth of fill
R/W width
gradient
11
1.51
Sizing the Pipe
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• Include:
amount of skew to road r/w
C/L
Factors Influencing
Culvert Length
Sizing the Pipe
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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Velocity Refuge (Shadows)
Roughness reduces velocity and creates shadows
Embedment Materials
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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Embedded pipes -modeling/simulating
the natural streambed
Embedment Materials
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• Size similar to that found in adjacent
natural streambed
Natural Stream Channel Embedment Material
“Rule of Thumb”
Embedment Materials
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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• Design should specify composition and distribution sizes of material to be used
Range of Material Size
Embedment Materials
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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%
Range of Material Size
Defn. D90 is the size of which 90% of the material will be smaller than
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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35%
15%25%
25%
Cobble Gravel Fine Boulder
General Size Distribution of Embedded Material
Embedment Materials
Range of Material Size
Rule of thumb - aka George Robison
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
32Design Drawings
Site Plan / Profiles
- Plan/profiles
developed for the
crossing
- design drawings
developed from site
plan / profiles
- used for design and
documentation
purposes
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
33Design Drawings
Site Plan
- contour map
of the site
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
35Design Drawings
Culvert
Profile
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
36Design Drawings
Road profile
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
37Design Drawings
Plan Drawing
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
38Design Drawings
Riprap Specifications
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
39Design Drawings
Installation Measures
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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Installation Referencing
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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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
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
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Plan View
Weir
Flow
Longitudinal View
WeirWeir Design
Design Drawings
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
43Design Drawings
Weir Design
Kamloops, March 12, 2002Design and Installation of Embedded Culverts
44Design Drawings Summary
• Stream data
• Plan
• Profile
• Construction referencing
(vertical / horizontal)
• Materials specifications
• Installation specifications
• other details (riprap, weir, etc.)
Design should include: