Floods in Pennsylvania, frequency and magnitude

This report outlines a method of determining the magnitude of floods having frequencies up to 50 years for any stream in Pennsylvania except regulated streams and streams whose drainage basins are smaller than 10 square miles. On the main stems of the Schuylkill, Delaware, Susquehanna, and Chemung Rivers the magnitude of floods can be determined for frequencies up to 100 years.

Six composite frequency curves show the relation of the mean annual flood to floods having recurrence interval up to 50 to 100 years. Curves for fourteen hydrologic areas show the variation of mean annual flood with drainage area. This report explains how to select the proper curves for any chosen point in the State and how to compute a flood-frequency curve for that point.

A tabulation of peak gage heights and discharges for most gaging stations in the State is included. In general, the tabulations contain all peaks above a specific base discharge, although for some stations only annual peaks are shown.