Stormwater consists of precipitation from rainwater or snowmelt as well as water that comes from sources like car washing or overwatering a lawn. Sometimes, rather than soaking into the ground, this water runoff gathers on impervious surfaces, such as curbs, asphalt roads, or driveways. Typically, the water is then channeled into natural or man-made drainage systems that are eventually released into streams, lakes, and rivers. This water can carry pollution into these natural water sources. Adopting and implementing a plan to reduce the discharge of stormwater pollutants and hazardous materials into water sources is known as stormwater control.
In addition to helping reduce potential water pollution, stormwater control serves several other functions. It can assist with flood and erosion control by regulating runoff water volume. In addition, professionals can plot out ways to protect or rehabilitate current natural water sources. Stormwater control can also mean implementing a plan to improve runoff water quality.
Stormwater control typically involves employing a combination of preventative and control measures. Preventative measures are designed to minimize the impact of water runoff in advance as well as to reduce both generation of and contamination of stormwater runoff. Prevention can include things like building rain gardens, which are small, landscaped plots of land that can assist in reducing stormwater runoff and filtering pollution. Another preventative measure is the use of permeable concrete, which allows water to filter though the concrete and into a reservoir underneath the pavement.
Control measures are targeted at capturing excess water flow and removing pollutants. For instance, pollutant removal systems can help filter or detain pollutants that exist in stormwater runoff. Cisterns, which are essentially storage tanks used for the purpose of capturing precipitation runoff, can help contain stormwater. The water stored in a cistern can then be used for other purposes, such as irrigating lawns or for toilet flushing. Surface depressions in sidewalks, known as runnels, can also be used to securely capture small amounts of runoff water.
In some countries, government agencies require certain businesses to adopt wastewater management plans. For example, pursuant to the Clean Water Act, the Environmental Protection Agency (EPA) oversees stormwater control regulations in the United States. A number of state and local governments within the United States have expanded on these federal regulations by adding additional stormwater management requirements. In Europe, stormwater control is governed by the European Environment Agency (EEA), and in Australia the Department of the Environment, Water, Heritage and the Arts monitors stormwater regulations.
Companies commonly impacted by stormwater control laws include land and building developers, construction contractors, and property managers. These companies may be required to obtain permits prior to beginning projects and to adhere to certain stormwater management practices. In some countries, property owners may also be subject to ordinances designed to reduce stormwater effects. For example, property owners may be required to minimize the use of fertilizers and pesticides on their lawns or to dispose of household wastes in a certain manner to eliminate potential water pollution.