Data Release of Basin Characteristics, Generalized Skew Map, and Peak-Streamflow Frequency Estimates in Oklahoma, 2017 (ver. 1.1, September 2020)

The U.S. Geological Survey (USGS) Oklahoma-Texas Water Science Center, in cooperation with the Oklahoma Department of Transportation, updated basin-characteristic data for Oklahoma streams with drainage areas of less than 2,510 square miles. Basin characteristics were updated or created for 248 streamgages. The previously published Oklahoma generalized skew map, a necessary element in the development of the peak-streamflow frequencies was updated. Compared to a previous dataset described in (Lewis, 2010), this dataset incorporates an additional 9 years of annual peak-streamflow data, including 2 years when major peak-streamflows were recorded (2015 and 2017). The additional years of data collection since the publication of Lewis (2010) also means that several additional streamgages now have an adequate number of years of record for frequency analysis. Some streamgages that provided data for Lewis (2010) have subsequently been determined to be influenced by regulation or were outside of the modified study area and were therefore omitted from this revised dataset. Basin characteristics were determined at each streamgage location by using a geographic information system (GIS) and Bulletin 17B methodology to create an updated Oklahoma generalized skew map. The basin-characteristic data and generalized skew map can be used to asses peak streamflows for unregulated streams in Oklahoma.