Storm Water Planning, Permits and Emergency Response in Grand Rapids
What is Storm Water?
Stormwater is a water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system. Stormwater that does not soak into the ground becomes surface runoff, which either flows directly into surface waterways or is channeled into storm sewers, which eventually discharge to surface waters.
Stormwater is of concern for two main issues: one related to the volume and timing of runoff water (flood control and water supplies) and the other related to potential contaminants that the water is carrying, i.e. water pollution.
Stormwater is also a resource and ever growing in importance as the world's human population demand exceeds the availability of readily available water. Techniques of stormwater harvesting with point source water management and purification that can potentially make urban environments self sustaining in terms of water.
Storm Water Managmenet
Managing the quantity and quality of stormwater is termed, "Stormwater Management."[5] The term Best Management Practice (BMP) is often used to refer to both structural or engineered control devices and systems (e.g. retention ponds) to treat polluted stormwater, as well as operational or procedural practices. There are many forms of stormwater management and BMPs, including:
• manage stormwater to control flooding and erosion;
• manage and control hazardous materials to prevent release of pollutants into the environment (source control);
• plan and construct stormwater systems so contaminants are removed before they pollute surface waters or groundwater resources;
• acquire and protect natural waterways where they still exist or can be rehabilitated;
• build "soft" structures such as ponds, swales or wetlands to work with existing or "hard" drainage structures, such as pipes and concrete channels;
• revise current stormwater regulations to address comprehensive stormwater needs;
• enhance and enforce existing ordinances to make sure property owners consider the effects of stormwater before, during and after development of their land;
• educate a community about how its actions affect water quality, and about what it can do to improve water quality; and
• plan carefully to create solutions before problems become too great.
Stormwater Pollution
Because impervious surfaces (parking lots, roads, buildings, compacted soil) do not allow rain to infiltrate into the ground, more runoff is generated than in the undeveloped condition. This additional runoff can erode watercourses (streams and rivers) as well as cause flooding after the stormwater collection system is overwhelmed by the additional flow. Because the water is flushed out of the watershed during the storm event, little infiltrates the soil, replenishes groundwater, or supplies stream baseflow in dry weather.
Pollutants entering surface waters during precipitation events is termed polluted runoff. Daily human activities result in deposition of pollutants on roads, lawns, roofs, farm fields, etc. When it rains or there is irrigation, water runs off and ultimately makes its way to a river, lake, or the ocean. While there is some attenuation of these pollutants before entering the receiving waters, the quantity of human activity results in large enough quantities of pollutants to impair these receiving waters.
