A determination of a storm runoff rate for assessing the impact of nonpoint runoff on a second-order stream

The purpose of this study was to determine a storm design frequency for assessing nonpoint runoff on a second-order stream. Beaver Creek,.a second-order stream (< 50 cfs), was simulated using a model verified by Weeter and Meadows. Taking five year storm frequency flows as the initial lateral inflow, the flows were reduced in increments until the model's dissolved oxygen (D0) profile no longer violated the in-stream standard of 5 mg/1 D0. At this point, the runoff flow was converted to a storm frequency. The design frequency recommended for use in nonpoint assessment studies for second-order streams in areas similar to East Tennessee in topography and climatology is 1.1 inches of rain per 24 hours or a one year storm frequency.