HOMS COMPONENT

MEASUREMENT OF PEAK DISCHARGE AT WIDTH CONTRACTIONS BY INDIRECT METHODS

1.   Purpose and objectives

     To compute peak discharge through open channel width contractions.

2.   Description

     The manual includes field and office procedures. The discharge equation based on the continuity and energy equations between an approach cross section and the contracted section under a bridge or other contraction is given. Contractions are classified into four geometric types. Discharge coefficients and computation procedures are given with a complete example of computation of a contracted opening measurement. Procedures are given for use with multiple opening contractions.

3.   Input

     Channel geometry and high-water marks from a recent flood.

4.   Output

     The peak discharge of the flood.

5.   Operational requirements and restrictions

     Best results will be obtained when applied by a person experienced in open channel hydraulics to a suitable contracting reach with good high water marks.

6.   Form of presentation

     Manual in English.

7.   Operational experience

     Extensive.

8.   Originator and technical support

     U.S. Geological Survey.

9.   Availability

     From the HOMS National Reference Centre for USA.

10.  Conditions on use

     None.

Last updated: 20 SEP 88)
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