TRANSIENT-RESPONSE OF LAKE SYSTEMS TO PHOSPHORUS

Impoundments and lake systems become eutrophic through excessive nutri ent (phosphorus and nitrogen) loadings. Deterioration of water quality because of algal blooms has forced many water quality control boards to adopt measures to reduce discharge of such nutrients into the water bodies. Phosphorus is the nutrient that is selected most frequently f or control as there are fewer pathways ways for it to enter a lake tha n there are for nitrogen. For instance the Virginia Water Control Boar d has adopted an average monthly limit of 2 mg/l of total phosphorus i n the effluent of about forty wastewater treatment plants in the Chesa peake Bay Drainage Basin [1].