presented by: timothy w. reed, p.e., cpesc · mega-ditch batter chute, southbridge, ma. corrugated...
TRANSCRIPT
Building Trust. Engineering Success.
Batter Chute DesignPresented by:
Timothy W. Reed, P.E., CPESCProject Director / CAD Services Manager
Sanborn, Head & Associates, Inc.October 2, 2018
Experience P.E. – NH, MA, ME CPESC - 2011 Solid waste designer for 20+ years Industrial facility drainage and landfill cell
and closure construction projects
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What is a Batter Chute?A batter chute or “drainage chute” is a steep drainage channel that passes down the face of a slope.
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Natural ConditionIn nature, water finds the path of least resistance.
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EngineeredEngineered batter chutes are typically more uniform and range from concrete-lined dam spillways…
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Engineered… to riprap-lined channels.
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The Power of Water
7Oroville, California dam spillway failure – March 2017
Landfill Final Cover System Steep slopes (3H:1V) Tall slopes (> 100 feet) Limited area Perimeter roads Detention basins Highly regulated
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Landfill Cap System
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Gabion-Lined Downchute
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Landfill Cap System
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Landfill Cap System
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Anatomy of a Batter Chute
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CHANNEL
INLET(S)
OUTLET1X
Anatomy of a Batter Chute
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1X
SUBCRITICAL FLOW
SUBCRITICAL FLOW
SUPERCRITICAL FLOW
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Froude Number and Critical Depth
Fr = v/(g hm)1/2
The Froude Number is “the inertia force on an element of fluid to the weight of the fluid element”
v = velocity
g = acceleration of gravity
hm = hydraulic mean depth
hm = A / TT = width of channel open surface
A = cross-sectional area
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Inlet Erosion Protection
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1X
y1
y2TRASITION ZONE IS
POTENTIAL AREA FOR EROSION
SUBCRITICAL FLOW
SUPERCRITICAL FLOW
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SUMP
VAULT
BASIN
DRAINAGE CHUTE
Channel Erosion Protection
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1X
SUPERCRITICAL FLOW
y2
Manning’s Equation
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Q = VA = ( )AR2/3S1/2
1.49nV = ( )R2/3S1/2
1.49n
Channel Geometry
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TRAPEZOIDAL TRIANGULAR
RECTANGULAR PARABOLIC
Channel Erosion Protection Rock needs to be large and angular to stay
on slope Rock can be secured (gabion or grouted in
place) Alternative armoring system can be used
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Rock-Filled Gabion Baskets
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Corrugated HDPE-Lined Swale
26MEGA-DITCH BATTER CHUTE, SOUTHBRIDGE, MA
Corrugated HDPE-Lined Swale
27MEGA-DITCH BATTER CHUTE, SOUTHBRIDGE, MA
Corrugated HDPE-Lined Swale
28MEGA-DITCH BATTER CHUTE, SOUTHBRIDGE, MA
Geomembrane-Lined Swale
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Centralized Sediment Mgmt.
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Geoweb/Geocell
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Geoweb/Geocell
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Articulated Concrete Block
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ARMORFLEX BY CONTECH
Grout-Filled Geotextiles
34ARTICULATING BLOCK MATS BY SYNTHETEX
Outlet Erosion Protection
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1X
SUBCRITICAL FLOW
SUPERCRITICAL FLOW
Stable Outlet Options
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DROP-INLET HEADWALL
PLUNGE POOLENERGY
DISSIPATER
Outlet Erosion Protection
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Basin Inlet
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Location of the Hydraulic Jump
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CASE A CASE B
CASE C
VELOCITY HIGH AND DEPTH LOW = JUMP
AWAY FROM TOE
VELOCITY AND DEPTH MATCHES =
JUMP CLOSE TO TOE (OPTIMAL)
VELOCITY HIGH AND DEPTH HIGH = JUMP
OCCURS OVER SLOPE (POTENTIAL
FOR PROBLEMS)
Hydraulic Above the Channel
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ACTS LIKE A HYDROFOIL (AIRPLANE WING)
Case C – Resulting in Damage
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Consider Below-Grade Flow
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Size Recess Based on Flow
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SIZE A RECESS TO ENSURE THAT JUMP OCCURS CLOSE TO THE TOE OF SLOPE
Z
Sizing Guidance
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Additional Design Information
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Catchments & Creeks
https://www.catchmentsandcreeks.com.au/index.html
Additional Design Information
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Design and Construction of Urban Stormwater Management Systems, ASCE, 1992 Older document >700 pages
Additional Design Information
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Questions?
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Thank You!
Building Trust. Engineering Success.
Timothy W. Reed, P.E., CPESCProject Director / CAD Services Manager
Sanborn, Head & Associates, [email protected]
www.sanbornhead.com