Urban Stormwater


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    Urban Stormwater


    When it rains or snows water flows over the land surface, heading downhill to the nearest stream or ditch, this is called stormwater runoff.

    In urban settings, water cannot soak through pavement and rooftops like it can into the soil. As a result, cities have larger amounts of stormwater runoff than forests and fields do. Water flows off of impervious surfaces (such as driveways, rooftops, sidewalks, and parking lots) and then collects in gutters or basins which run directly into storm
     drains. These drains carry the water as well as other toxic chemicals  directly to lakes and streams.

    Water quality in an area generally starts to become impaired when impervious land cover rises above 10 percent. The more impervious cover, the greater the risk that your watershed is contaminated.


    tunnel drainIn recent years, the Intermountain West has experienced some of the fastest urban growth in the United States. With an increasing population comes an increased demand for water resources, particularly in watering lawns and gardens. Because the west's water consumption has increased the Colorado River now runs dry before it can reach the sea.

    This rapid urban growth and water consumption are detrimental to Utah's native desert ecosystems which are extremely delicate and take hundreds of years to develop.  Unfortunately impervious surfaces and construction complicate the problem by introducing pollutants into the ecosystem. During dry periods between rain events, pollutants build up on these surfaces. The first storm after a long dry period then creates a “first flush,” sending that high concentration of pollution into the watershed.