When Lewis and Clark journeyed across the United States they navigated many streams, lakes, and rivers across the continent. When they camped, they thought nothing of taking a bucketful of water from a nearby stream and drinking from it, cooking with it, or bathing in it. Things are a lot different nowadays. Our streams are filled with pollutants, and our water has to be treated and purified before it can be used. How did our water resources get to that point, and why can't something be done about it?
Well, something is being done. The State of Indiana recently passed regulations to control "stormwater runoff," which is a major pollutant in Indiana's waterways. Controlling stormwater runoff is a big step towards cleaning up our water resources.
It helps to understand how water flows, which in turn helps you understand the impact stormwater runoff has on our water resources. Here are a few frequently asked questions about stormwater:
What is a Watershed?
Every one of us lives in a watershed - areas that drain to a common waterway, such as a stream, lake, estuary, wetland, or ultimately, the ocean. In other words, a small creek may drain into a larger stream, which flows into a river, which may flow into an even bigger river before it reaches the ocean.
As you can see from the map above, watersheds come in all shapes and sizes. They also cross county, state, and national boundaries. Most of Clark County is contained in the Silver-Little Kentucky watershed (named for Silver Creek on the Indiana side of the Ohio River and the Little Kentucky River on the Kentucky side).
What is "stormwater runoff"?
Stormwater occurs naturally when it rains or snows. You probably have looked out the window of your home on a particularly rainy day and noticed the water flowing down the sides of the street. Where is it going? Well, water running off your yard, sidewalk or street flows down to the curb and into the nearest storm drain. From there, it flows into the storm drain system, a vast network of underground pipes and tunnels that carry it to nearby streams and lakes. Contrary to popular belief, stormwater normally does NOT go to the sewage treatment plant.
What happens when stormwater "runs off"?
As it runs off of rooftops, and lawns, and down driveways and streets, stormwater picks up pollutants and debris.
In developed areas, where much of the land surface is covered by buildings and pavement, water cannot soak into the ground. As a result, the stormwater flows over these impervious surfaces and picks up many toxic chemicals from motor oil, lead from gas and auto exhaust, and zinc from roof drains and tires. These chemicals may kill or impair the health of aquatic life.
Stormwater may also contain sediment (soil particles) if it is washed off construction sites. When sediment enters a lake or stream, the water appears cloudy or turbid. Over time, it will fill in a stream or lake as it settles out of the water. Phosphorus is a nutrient often attached to soil particles that fuels the growth of algae and aquatic weeds, plants that are important as fish and wildlife habitat. Too much phosphorus, however, can cause rapid and excessive growth of the plants and can degrade water quality, and interfere with swimming, boating, and fishing.
Bacteria, viruses, and other disease causing microorganisms can abound in stormwater that carries pet waste and litter. They make waterways unsafe for swimming and other types of water recreation. People who depend on lakes or streams for drinking water may be endangered because some microorganisms are difficult to remove through water treatment.
Other potential stormwater pollutants include:
Polluted stormwater runoff is also called "nonpoint source" (cannot be traced to a single source) pollution.