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Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds

Journal of Irrigation and Drainage Engineering

By:
, , , , and
DOI: 10.1061/(ASCE)IR.1943-4774.0000571

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Abstract

The rational method for peak discharge (Qp) estimation was introduced in the 1880s. The runoff coefficient (C) is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the C has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the return period, C(T), were determined for 36 undeveloped watersheds in Texas using peak discharge frequency from previously published regional regression equations and rainfall intensity frequency for return periods T of 2, 5, 10, 25, 50, and 100 years. The C(T) values and return period adjustments C(T)/C(T=10  year) determined in this study are most applicable to undeveloped watersheds. The return period adjustments determined for the Texas watersheds in this study and those extracted from prior studies of non-Texas data exceed values from well-known literature such as design manuals and textbooks. Most importantly, the return period adjustments exceed values currently recognized in Texas Department of Transportation design guidance when T>10  years.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds
Series title:
Journal of Irrigation and Drainage Engineering
DOI:
10.1061/(ASCE)IR.1943-4774.0000571
Volume
139
Issue:
6
Year Published:
2013
Language:
English
Publisher:
ASCE
Contributing office(s):
Texas Water Science Center
Description:
7 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Irrigation and Drainage Engineering
First page:
476
Last page:
482
Country:
United States
State:
Texas