Storm water runoff is water from rain that flows over the ground. Paved surfaces such as driveways, parking lots, and streets prevent storm water from naturally soaking back into the ground. Water flowing over paved surfaces becomes contaminated with debris, chemicals, dirt, and other pollutants. Also, storm water flowing across unpaved and un-vegetated ground can result in soil erosion and increased siltation in our streams. Eventually, this untreated water discharges to storm sewers that in turn discharge to nearby surface water bodies, which are used for swimming, fishing, and providing drinking water. We’ve all seen a stream or lake that looks muddy after a heavy rain.
The pollutants, which can include things like oil, gasoline, fertilizers, and pesticides, in addition to sediment and trash, can cause significant negative impacts in our wetlands, rivers, streams, lakes, and estuaries. It is important to prevent contaminants from entering the storm sewer system because pollutants are not removed before this water flows into our waterways.
Soil erodes when wind and rain carries away soil particles. Water runoff can carry fertilizers and other pollutants along with the soil. Nitrogen and phosphorous from fertilizers are associated with many environmental problems, such as nutrient pollution, when in excess. For example, streams, ponds, rivers, and other water bodies suffer from increased algae growth, which depletes the water’s oxygen supply and leads to suffocation of aquatic organisms. Signs of soil erosion include bare spots, exposed tree roots, rills and gullies on slopes, soil splashes on the windows and walls of a building, and sediment collected on paved areas.
Prevent soil erosion! If excess water is moving across the property, divert the water using logs or berms (high areas). For small diversions, plant or mulch the area once the water has been redirected. Consider planting sod or plants as an alternative to grass seed. A concrete splash block at the downspout outlet can also help control erosion. Direct roof and gutter runoff toward a grassy area or other planted area, a stream, or a street gutter. Runoff from roofs may be directed into a barrel and stored for later use. Groundcover, the layer of vegetation below the shrub such as grasses, vines, low shrubs, and mosses, is the most common solution to preventing erosion of steep slopes.
Some of the steps USPS has taken to prevent storm water pollution include the following:
n Developing plans that are designed to prevent storm water pollution and eliminate or reduce water pollution from petroleum products (oil, grease, lubricants, etc.)
n Whenever possible, moving stored chemicals indoors to eliminate exposure to storm water.
n Covering materials or operations to minimize exposure to storm water.
n Labeling drains at large facilities — “Don’t dump, leads to waterway.”
We all potentially contribute to storm water pollution with many of our everyday activities. Below are some examples of things you can do to reduce water pollution:
n Wash your car at car washes, which are required to treat their discharge. If you cannot do that, invest in a high pressure nozzle for your hose, which will minimize the total water volume.
n Pick up your pet waste from the yard and don’t drop it in storm sewers when taking the dog for a walk.
n Read the directions for fertilizers and apply them in appropriate amounts and at the appropriate times to minimize the chance they will get into storm water.
n Find alternatives to pesticide use. For example, eliminating food sources that attract pests can reduce pest populations that in turn reduce the water quality impacts of pesticides.
