Low-flow characteristics of small streams in proposed Public Law 566 basins

Abstract

Low-flow characteristics of Wisconsin streams in basins considered for work under Public Law 566 are presented in this report. The low-flow characteristics presented are the annual minimum 1-day mean flow below which the flow will fall on the average of once in 2 years (Q7,2) and the annual minimum 7-day mean flow below which the flow will fall on the average of once in 10 years (Q7,10). The low-flow characteristics are presented for 278 project sites in 32 basins considered for work under Public Law 566. They were determined by correlating base-flow measurements at the project site 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 an Q7,10 at the project sites. The accuracy of the estimated low-flow characteristics is evaluated according to the type and amount of data available used. The statewide average of the accuracy determined by the standard error of estimate for the 10-year low flow (SE7,10)> based on three base-flow measurements, is 45 percent but differs within the State.