This includes natural and artificial drainage systems, such as ditches and storm sewers. If we pollute a watershed, we directly affect the water quality in that lake, stream or river. In a natural watershed, much of the rain soaks into the soil of grassy or vegetated areas. However, in an urban watershed, rain runs off hard surfaces such as streets, driveways and rooftops. As rainwater flows from street to storm sewer, it picks up pollutants including oil, antifreeze, leaves, grass clippings, pet wastes and chemicals from lawns and gardens.
Storm sewers provide direct routes for pollutants to lakes and streams.
Lawn care Phosphorus, one of the most troublesome pollutants, is in leaves, lawn clippings, animal wastes and most lawn fertilizers. When phosphorus reaches a lake or stream it increases algae growth which then blocks sunlight and prevents other plants from growing. As algae decays, it also takes oxygen from fish. Protecting watersheds We are all part of the solution to water quality problems. Our actions affect the water and environment around us.