Dye-tracer studies were made in November 1978 and in June 1979 to define streamflow patterns in the Vermilion River. For the November 1978 study the tracer was injected at two locations, Surrey Street in Lafayette and about 7 miles downstream at State Highway 3073; the discharge at Surrey Street at the time of injection was 218 cubic feet per second. The two dye clouds merged at Broussard Cemetery, about 12.2 miles downstream from Surrey Street, after an elapsed time of about 270 hours. After 438 hours the dye cloud extended form the Abbeville bridge (Louisiana Highway 14 Bypass) upstream about 14.5 miles. In June 1979, a tracer was injected into the river at Surrey Street at Lafayette; the discharge at Surrey Street at the time of injection was 161 cubic feet per second. Forty-two hours after injection the leading edge of the tracer was located at the Milton pumping plant, 14 miles downstream from the injection site. The average pumping rate of the plant during the study was 440 cubic feet per second. Ninety hours after injection, no indication of the tracer was found in the river, but the tracer was found in a rice-irrigation canal at State Highway 14, about 10 miles west of Abbeville.
