ABSTRACT
The Walker Dam Impoundment Aquatic Plant Control Project is designed to control the profuse infestation of Brasilian water-weed Elodea through chemical treatment with a 50/50 mixture of diquat and potassium endothall. Selection of the best herbicides to eliminate the infestation of elodea on the Walker Dam centered around those which biodegrade rapidly, present minimal hazards to humans or other life, are readily accessible in desired quantities, are relatively inexpensive, and have been cleared for use in potable water supplies. A combination of two such herbicides, diquat and endothall, was applied to Chickahominy Reservoir, to control the nuisance weed Egeria densa. The toxicity of the herbicides within the reservoir system is dependent upon the initial concentrations and the contact time of the toxins. Two study areas at the reservoir, a quiescent bay and a slightly more lotic bay, were chosen for intensive study. The herbicide mixture was applied from an airboat to the surface of the reservoir.
