Phosphorus

Lake Dunlap has a phosphorus pollution problem! Why is phosphorus bad for the lake? Phosphorus is a nutrient that stimulates plant growth- that's why it is in most fertilizers. Excess phosphorus encourages algae growth. Too much algae results in algae blooms that turn the lake a cloudy green and cause ugly surface scum. As the algae die and decay, the lake looks and smells bad, discouraging swimmers and boaters. The decaying algae also use up the water-borne oxygen that fish need. Increased phosphorus, even in small amounts, reduces water quality. We all are aware of the summer months when the lake turns an ugly pea green and has an unpleasant odor that stays for months at a time. This is a result of cultural eutrophication, when phosphorous comes from several sources including human disturbances of the land and its vegetation, industrial wastes, human wastes, and animal wastes.

How does phosphorus get into the lake? Reports indicate that the bulk of the phosphorus entering our lake comes from the two NBU wastewater treatment facilities (located near the softball fields). Storm water and groundwater also carry phosphorus into the lake from a number of sources, including:

• Fertilizers from gardens and small farms
• Detergents
• Failing septic tanks
• Pet and livestock waste
• Soil that erodes during landscaping and development

So, even though we may not know it, each of us puts phosphorus into the lake-often by the things we do every day in our own backyards. We all contribute to the problem and we need to work together to solve it. Here are a few ways we can keep phosphorus out of the lake.

• Fertilize your lawn and garden sparingly-once or twice a year at most. Use compost or organic fertilizers not animal manure. Don't apply fertilizer when rain threatens. Use slow release fertilizers.
• Plant native plants and keep shorelines from eroding.
• Maintain your septic tank.
• Scoop your pet waste and dispose of it.
• Wash your car in gravel or on the lawn. Dumping “gray water” into the river is against the law and subject to a fine.