Communities that use fill-and-draw waste-water treatment lagoons or waste-stabilization ponds are required to discharge during the spring and fall of the year at a rate that does not exceed the assimilative capacity of the receiving stream. The 10-year low mean monthly discharge (MMQ10) for October, November, April, and May for the receiving stream has been used to establish the discharge rate for the treatment systems at the appropriate time of the year. To determine the MMQ10 for the receiving stream the monthly mean discharge first was estimated by using a technique developed by Riggs (1969). Once the monthly mean discharge was determined the MMQ10 of the ungaged stream was estimated by using a graphical correlation between the monthly mean discharge and the MMQ10 of at least three gaging stations near the waste-stabilization pond.The MMQ10 for these gaging stations were determined by a log-Pearson Type III frequency analysis.
The MMQ10 was determined for Maple Creek at Valmy, Aliens Creek near Oakdale, North Branch Manitowoc River at Sherwood, East Fork Poplar River near Curtiss, and Yellow River at Barronette.