Flushing time of the Maple River impoundment and methods in current measurements.

Abstract

The flushing time of Lake Kathleen (Maple River impoundment, adjacent to the Dam Site Inn; Pellston, Michigan) was determined by measuring the currents and cross-sectional areas in both the upstream branches, East and West, and downstream (below the Dam). By knowing the total water volume in the impoundment and the water volume moving through the streams per hour, the flushing time, the time required for daily discharge to move through a water body, can be determined. When the current measurements were made it would have been desireable to take readings at the surface waters. This data is necessary for obtaining a better estimate of the average velocity in the surface waters. Also it would have been helpful to take readings just above the stream bottom. In taking the actual measurements a digital readout would be helpful. Because the surveying was not completed only a very rough estimate of the impoundment (central basin) volume was made. The approximate flushing time is: 3 days & 21 hours.