What's a Watershed?

We all live within a "watershed", which is all of the land area that drains into a given body of water. Even if you don't live next to a pond or lake, your activities can still have an impact on water quality within your watershed. Follow the link at left to learn about local watershed management organizations.

Water Drain

Watersheds are like gigantic funnels. Each time it rains, water runs off onto the streets from impervious surfaces like your driveway and house, as well as from nearby commercial buildings and parking lots. From there, it enters the storm drains and empties directly into the nearest pond or lake untreated.

Water Quality

All of this runoff and the pollutants it carries can degrade water quality and affect the health of our aquatic ecosystems. Fortunately, many of the pollutants in our watershed can be prevented through proper lawn care, erosion control and chemical disposal.

Where Does Your Water Go?

Water is necessary to sustain life on Earth. In fact, humans cannot live for more than a few days without it. Our water was created when the Earth was formed, which makes it more than 4 billion years old. Since then, very little water has been created or lost. All the water we have is all the water there will ever be, so we must protect this valuable natural resource.

The Water Cycle

Water naturally runs through a continuous cycle.

Water cycle illustration

First, the sun heats surface water, which causes some of it to evaporate. Water vapor is also released by plants through the undersides of their leaves. This is called transpiration.

Next, water vapor rises into the Earth's atmosphere, cools and condenses when it comes into contact with warmer air. This is similar to when your bathroom mirror fogs up after you take a hot shower. Clouds are comprised of large amounts of condensed vapor and if the air stays warm, vapor will continue to collect and form large drops.

When these drops become heavy, they fall to the Earth as rain. Some of the rain is absorbed by plants; some infiltrates into the ground to become ground water, and some runs over the ground's surface and enters our ponds, lakes and streams.

The more we cover the ground with impervious surfaces, like roads and buildings, the more rainwater that will runoff into our surface waters instead of being absorbed into the ground. Many urban pollutants are carried by rainwater and when they enter our ponds, lakes and streams, they degrade water quality.

Did you know that…?

  • All pollutants in the street - including grass clippings, fertilizer, oil, antifreeze and sediment - go directly into your nearby pond or lake when it rains!
  • One pound of the nutrient phosphorus found in fertilizers and in plant material such as grass clippings can support over 500 pounds of algae!
  • Burnsville's ponds, lakes and streams drain into the Mississippi River, and ultimately into the Gulf of Mexico! Excessive amounts of sediment and nutrients have created a "dead zone" for biological growth in the Gulf of Mexico.
  • Improving water quality in Burnsville will help improve water quality in the Mississippi River and ultimately the Gulf of Mexico.