Welcome to www.a2gov.org/storm: This site is designed to be a resource on stormwater management and surface water quality issues in the City of Ann Arbor. The site provides:
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What is stormwater?
Stormwater is runoff from rain or snowmelt that flows off streets, rooftops, and lawns into storm drains. From storm drains, runoff flows directly into streams, lakes and rivers. Unlike wastewater, which is treated at a wastewater treatment plant, stormwater receives no treatment before being discharged to surface waters. In Ann Arbor, all stormwater (and any pollutants carried by stormwater) are discharged to the Huron River and its tributaries. |
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Why is stormwater a problem?
Both the quantity and quality of stormwater runoff can negatively impact the local water resources that provide drinking water, recreation, and wildlife habitat.
Water Quantity - Once land is urbanized, very little water is able to infiltrate into the ground, and instead, is rapidly conveyed via storm drains or surface runoff to the nearest water resource. Higher volumes of stormwater runoff can cause flooding, erosion, and property damage. This results in significant changes in stream flow and wetland hydrology, which can cause stream bank erosion and loss of aquatic habitat.
Water Quality - Stormwater runoff picks up anything in its path and delivers it to the nearest creek or river. The pollutants carried by stormwater can degrade the quality of our waterways, making them unhealthy for people, aquatic life, and wildlife. Stormwater from the initial half inch of rain tends to carry the most pollution as it washes fertilizers, automotive fluids, animal waste, deicers, and dirt from the land surface into the storm drains.
Urban watersheds typically exhibit:
- Increased run-off volume due to greater impervious surface and lower tree canopy
- Increased peak discharge rates due to highly efficient drainage systems
- Diminished baseflow, or dry weather flow, due to decreased groundwater infiltration
Managing Stormwater
Stormwater management is any vegetative, structural, or managerial practice used to treat, prevent, or reduce the volume of runoff water that impacts surface or groundwater. The City of Ann Arbor works to manage stormwater in conjunction with land use change in order to protect water quality and reduce impacts of stormwater on local water resources.
Last Update: January 19, 2010