Channel Slope Effect on Peak Discharge of Natural Streams

The Channel Slope Method provides a reasonable approach to the apparent need for a reasonable method of computing peak runoff rates for natural streams. Stream runoff data from the U.S. Geological Survey were correlated with the slope of the stream channel. The data were plotted on logarithmic paper with stream channel slope in ft/mi as abscissa and unit runoff in cu ft/sec/acre as ordinate. A straight line envelopes all the plotted points and gives the equation of the unit runoff for a particular recurrence interval. The designer who must determine waterway openings for bridges or culverts or design flows for flood plains, can obtain a conservative answer to the peak discharge for a given recurrence interval by this method.