DISCALC: a computer algorithm for computing the flow characteristics of flood discharges in stream channel cross sections

Geomorphologists occasionally desire estimates of flow conditions for past or future flood events. Manual methods for computing flow characteristics of flood discharges may be time-consuming and tedious. Computational shortcuts involving the substitution of depth of flow for hydraulic radius in hydraulic equations may yield results with significant bias. DISCALC is a computer program that calculates uniform-flow characteristics of flood discharges within stream-channel cross sections. It eliminates computational bias by calculating hydraulic measures based on their precise mathematical definitions. The algorithm contains an iterative routine that converges on the desired discharge by changing the vertical position of the water surface within the stream-channel cross section. The program is capable of handling single thread as well as multithread channels. It also contains options for displaying results on a color monitor or a plotter.