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OLS Field Name OLS Field Data
Main Title Design Stream Flows Based on Harmonic Means.
Author Rossman, L. A. ;
CORP Author Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab.
Publisher c1990
Year Published 1990
Report Number EPA/600/J-90/470;
Stock Number PB91-182204
Additional Subjects Stream flow ; Water quality ; Water pollution standards ; Fourier analysis ; Mathematical models ; Concentration(Composition) ; Statistical analysis ; Risk assessment ; Water pollution effects ; Rivers ; Water flow ; Environmental protection ; Public health ; Study estimates ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB91-182204 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 09/04/1991
Collation 7p
Abstract Design streamflows are frequently used in water quality studies to provide adequate protection against pollutant exposure periods of a given duration. By analyzing the effect that simple streamflow dilution has on x-day average exposure levels of a pollutant, it appears that the x-day harmonic mean flow is a more meaningful statistic to use in computing design flows than is the customary arithmetic mean flow. The significance of the result was examined by computing design flows for sixty rivers throughout the country. For 7- and 30-day average annual low flows the impact was minimal. Substantial differences were found for the overall mean daily flow--a design flow suggested for use with water quality criteria based on protecting human health against lifetime exposures. The overall harmonic mean daily flow is typically 20 to 60 percent as large as the arithmetic mean daily flow. For ungaged streams it can be estimated from estimates of the arithmetic mean flow and the 7-day, 10-year low flow by regional regression analysis.
Supplementary Notes Pub. in Jnl. of Hydraulic Engineering, v116 n7 p946-950 Jul 90.
NTIS Title Notes Journal article.
Title Annotations Reprint: Design Stream Flows Based on Harmonic Means.
Category Codes 68D; 68G; 48G; 57U
NTIS Prices PC A02/MF A01
Primary Description 600/14
Document Type NT
Cataloging Source NTIS/MT
Control Number 117926968
Origin NTIS
Type CAT