Impoundment Destratification by Mechanical Pumping

Mechanical pumping was used to break up thermal stratification in four lakes in southern Ohio during the summer of 1964. The lake volumes were 98, 100, 120, and 1260 acre-ft. Each impoundment was thermally and chemically stratified before pumping began. The equipment was a pontoon-mounted, axial-flow pump, 13 acre-ft per day capacity, driven by a gasoline engine. The pump drew water from the bottom and discharged it at the surface. Profiles of temperature, pH, and concentrations of dissolved oxygen and carbon dioxide were taken before and after pumping. Data presented show that this method was effective in destratifying these lakes. In addition, the data show that water quality was improved by artificial destratification and that an entire impoundment could be mixed with the pump located at a single position. Some data are presented on total work requirements, but these were found to be dependent on the efficiency of the mechanical equipment and the percentage of cold water in the impoundment before pumping.