The lake is a river system, it rarely backflows, during the time the beaches were closed there is no way the lake was backflowing with the amount of water that was being pulled at the dam. Look on the MoDNR site at the latest samples. The July samples have been within tolerable limits, while the samples that exceeded the limits were taken at the end of May (a high water period). The mass of contamination is coming from the tributaries and it is a natural process. The amount of runoff volume that comes from lakefront properties is not even comparable to the volume that comes from the watershed. If the beach closures come during high water periods when we are getting that high volume of runnoff, wouldn't it make sense that is where the vast majority of the contaminants come from?