presented by: timothy w. reed, p.e., cpesc · mega-ditch batter chute, southbridge, ma. corrugated...

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

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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, Inc.treed@sanbornhead.com

www.sanbornhead.com