U.S. Army Corps of Engineers permits are required for discharges of dredged or fill-material downstream from the ' headwaters ' of specified streams. The term ' headwaters ' is defined as the point of a freshwater (non-tidal) stream above which the average flow is less than 5 cu ft/s. Maps of the Mobile District area showing (1) lines of equal average streamflow, and (2) lines of equal drainage areas required to produce an average flow of 5 cu ft/s are contained in this report. These maps are for use by the Corps of Engineers in their permitting program. (USGS)