Estimating the magnitude and frequency of low flows of streams in Massachusetts

Water-Resources Investigations Report 94-4100



The report presents techniques used for estimating 7-day 2-year (7Q2) and 7-day 10-year (7Q10) flows at continuous-record streamflow-gaging stations, partial-record stations, and ungaged sites on streams in Massachusetts. A two-parameter log-normal probability distribution was used to compute low flows at 31 continuous-record stream-flow-gaging stations. Graphical and mathematical techniques were used to estimate low flows at partial-record stations. Regional regression techniques commonly are used to estimate 7Q2 and 7Q10 flows at ungaged stream sites. The development and application of a low-flow regression model is described. The model contains two parameters, mean and standard deviation, computed from separate regression equations that use total drainage area and basin relief as independent variables. The coefficients of determination of the mean and standard deviation regression equations are 0.964 and 0.960, respec- tively; the percentage of standard error of the regression of each equation are 35 and 34, respec- tively. The model is applicable for basins in Massachusetts having a drainage area of 5 to 150 square miles, a slope of less than 4 percent, and an area of stratified drift greater than 4 percent of the total drainage area. A computer program is presented that can be used to compute 7Q2 and 7Q10 flows and the 95-percent intervals of confidence and prediction for a given basin.

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Estimating the magnitude and frequency of low flows of streams in Massachusetts
Series title Water-Resources Investigations Report
Series number 94-4100
DOI 10.3133/wri944100
Edition -
Year Published 1994
Language ENGLISH
Publisher U.S. Geological Survey ; USGS Earth Science Information Center, Open-File Reports Section [distributor],
Description iv, 29 p. :ill., maps ;28 cm.
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