Dye tracer tests to determine time-of-travel in Iowa streams, 1990–2006

Dye-tracing tests have been used by the U.S. Geological Survey, Iowa Water Science Center to determine the time-of-travel in selected Iowa streams from 1990-2006. Time-of-travel data are tabulated for 309 miles of stream reaches in four Iowa drainage basins: the Des Moines, Raccoon, Cedar, and Turkey Rivers. Time-of-travel was estimated in the Des Moines River, Fourmile Creek, North Raccoon River, Raccoon River, Cedar River, and Roberts Creek. Estimation of time-of-travel is important for environmental studies and in determining fate of agricultural constituents and chemical movement through a waterway. The stream reaches range in length from slightly more than 5 miles on Fourmile Creek, to more than 137 miles on the North Raccoon River. The travel times during the dye-tracer tests ranged from 7.5 hours on Fourmile Creek to as long as 200 hours on Roberts Creek; velocities ranged from less than 4.50 feet per minute on Roberts Creek to more than 113 feet per minute on the Cedar River.