The hydraulics of flow was investigated at two reaches in the Kaskaskia River. The discharge varied from 58 to 4000 cfs and the flow frequency varied from 5 to 88 percent. The head loss varied from 0.96 ft/ mile for high flows to 1.98 ft/mile for low flows. The vertical velocity distribution was found to follow a logarithmic distribution. A theoretical distribution predicted the lateral velocity distribution in the bends reasonably well. In all, 79 isovels were developed for all flow conditions. The average value of the energy coefficient was 1.45 for straight reaches and 1.43 for bends. Similarly, the average value of the momentum coefficient was 1.22 for straight reaches and 1.18 for bends. Manning’s roughness coefficient varied from 0.039 to 0.053. During low flows. the river flows through a series of pools and riffles. The median diameter of bed materials varied from 40 mm in the riffle to 0.04 mm in the pool, whereas the Froude number changed from 0.7 to 0.01. During high flows, the effect of the pool and riffle on the flow condition is minimal or nonexistent.publishedpeer reviewedOpe
