Charles Parrett Stephen R. Holnbeck 1996 Flood hydrographs for 26 gaging stations and rainfall data were used together with a rainfall-runoff simulation model to derive unit hydrographs and important unit-hydrograph variables. Methods were developed for estimating unit hydrographs at ungaged sites using either the Clark or dimensionless unit-hydrograph methods. The 26 derived unit hydrographs were compared with those calculated by the two estimation methods. The two methods performed about equally well in matching derived unit-hydrograph peaks and shapes. application/pdf 10.3133/wsp2420 en U.S. Geological Survey Procedures for estimating unit hydrographs for large floods at ungaged sites in Montana reports