FLOOD08281

• County: Statewide
• Basin: Statewide
• Title: Design Criteria for Riprap Drop Structures
• Date: 1/26/1982
• Prepared For: US
• Prepared By: UDFCD
• Floodplain - Doc Type: Educational/Technical/Reference Information

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REVI EW C.OPY

L. Scott Tuoker. E)C8Cutive Direclor
T<<IIuurer

RIPRAP DROP STRUCTURES
DESIGN CRITERIA

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INTRODUCTION

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The most common use of drop structures is to control the
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CIly"_ g longitudinal slope of grass lined channels to keep design velocities
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noIIIIU~::= ffi' Figure 1. are two possible types of drop structures.
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~~~ The Urban Drainage and Flood Control District (UD&FCD) has studied

~ ,~ riprap drop structures and has developed criteria and charts to aid in
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CIly"'" 1II:t the design of these types of structures. This publication presents the
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~~; background for the criteria and design charts, a general discussion of
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_A.COnIII" the drop structures. and example problems.
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OaWlA.Doy III The criteria presented herein are preliminary in that additional
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CIlyol_' been developed after considerable and careful research and deliberation.
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~~::: However. any criteria of this nature should have the flexibility to
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_E._ ~ account for additional field experience.
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.L.~.~ ~ The criteria contained in this publication should be used in
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conjunction with the preliminary revision of the riprap section of the

Urban Storm Drainaqe Criteria Manual (dated June. 1981). This revision

contains the necessary information regarding riprap gradation. bedding