From the Purpose and Scope: "This report presents the estimated magnitude of flood flows associated with the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs for 356 streamflow gaging stations (referred to hereafter as streamgages) across Pennsylvania and surrounding states not subject to substantial flow regulation, diversion, or mining activity. [...] The streamgages included in the study had a minimum of 10 years of data through water year 2015. The report also documents a regional skew analysis, trends in annual peak streamflow data, and development of regional flood-flow regression equations from the relation of flood-flow and basin characteristic data. The resultant regression equations allow for the computation of flood flows at ungaged basins across Pennsylvania by means of select basin characteristics that are significantly correlated with streamflow. Estimates of floodflow magnitude and frequency for streamgages substantially affected by upstream regulation are also presented. The limitations of the study and uncertainties of the flood-flow estimates are also discussed."
United States. Department of the Interior; Geological Survey (U.S.)