In 1970, despite the expansion of Blue Plains and the construction of several other facilities downstream in Virginia and Maryland, the situation reached crisis proportion again. Overflows of combined sewer and storm drains introduced more raw sewage into the Potomac than in 1932 when no treatment plants existed. The Potomac was also overloaded with nutrients, such as nitrogen and phosphorus, producing thick mats of algae downstream of Mt. Vernon that chocked more than 100,000 acres of the river during the summer months. Urban dwellers can recycle used motor oil and avoid putting household toxics, such as oven cleaners, down the drain. Suburban homeowners can restrict the use of fertilizers and pesticides on lawns and gardens and can minimize erosion by keeping yards grassed and using splash blocks at downspouts.
Rural residents can make sure that septic systems are maintained in good order.
Developers can install effective anti - siltation devices to keep exposed soil from washing into streams during construction. January 15, 1996.