Development of Regression Models to Estimate Flow Duration Statistics at Ungaged Streams in Oklahoma Using a Regional Approach

摘要

Multiple-regression analysis was used to develop equations for estimating annual andseasonal flow-duration statistics at ungaged streams in and near Oklahoma that are notsubstantially affected by human alteration. Ordinary least-squares and left-censored (Tobit)multiple-regression techniques were used to develop equations that relate these statistics, fromcontinuous streamflow data at gaged locations with 10 or more years of record, to physical andclimatic basin characteristics. Separate equations were developed to estimate these statistics forstations within similar hydrologic and geologic regions. Use of separate regressions by regionsubstantially improved the accuracy of the estimate for streams in eastern and central Oklahomawhen compared with estimating equations developed for the entire State, especially forregressions estimating lower flow duration values. For all regions, the equations were morereliable for estimating higher flow duration values. The accuracy of regressions for estimatingflow duration statistics in western Oklahoma was very poor, especially for lower flow durationvalues.