Low-flow characteristics of Wisconsin streams at sewage-treatment plants
Water-Resources Investigations Report 74-45
Prepared in cooperation with the Wisconsin Department of Natural Resources
- W.A. Gebert and B.K. Holmstrom
Low-flow characteristics of Wisconsin streams at 415 sewage -treatment plants are presented in this report. The low-flow characteristics presented are the annual minimum 7-day mean flow that occurs on the average of once in 2 years (Q7, 2) and the annual minimum 7 -day mean flow that occurs on the average of once in 10 years (Q7, 10).
The low-flow characteristics at most sewage-treatment plants were determined by correlating base-flow measurements at the sewage- treatment plants to the concurrent daily mean flow at continuous-record gaging stations in the area. The Q7, 2 and Q7, 10 discharges determined by a frequency analysis at the continuous-record gaging stations were used to estimate the Q7, 2 and Q7,10 at the sewage-treatment plants. For some sewage-treatment plants the low-flow characteristics were also determined by frequency analysis at nearby continuous -record gaging stations or correlation analysis at nearby low-flow, partial-record stations.
The accuracy of the estimated low-flow characteristics is evaluated according to the type and amount of data available used to determine the low-flow characteristics. The accuracy determined by the standard error of estimate for the 10-year low flow (SE10) ranged from 18 percent at continuous -record gaging stations to 70 percent when only three base-flow measurements were available.
The SE10 of 70 percent is larger than anticipated when the project was initiated. This was the result of extremely poor base-flow conditions during the 2-year data-collection period.
Additional publication details
- Publication type:
- Publication Subtype:
- USGS Numbered Series
- Low-flow characteristics of Wisconsin streams at sewage-treatment plants
- Series title:
- Water-Resources Investigations Report
- Series number:
- Year Published:
- U.S. Geological Survey
- Contributing office(s):
- Wisconsin Water Science Center
- vi, 101 p.
- United States
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