Projections of Phosphorus Levels in White Lake

A preliminary mathematical model of phosphorus was used to evaluate different lake rehabilitation schemes for improvement of water quality in White Lake, Michigan. Model calculations indicate that phosphorus loss to the sediments and phosphorus removal by the tributary flow are two key processes responsible for rapid system response under reduced phosphorus loading rates. The sediments had little effect on the initial recovery following load reduction but play an important role in determining the ultimate equilibrium concentrations of phosphorus. Rehabilitation schemes such as aeration and circulation result in additional improvement in water quality beyond that provided by the present sewage diversion project alone. Additional reduction of phosphorus concentrations could be achieved by control of nonpoint sources which constitute about 80% of the total input to the lake.