The County's stream system has suffered damage because of a historic lack of adequate stormwater control. In an effort to prevent future stormwater-generated problems, the County has embarked on a three-part watershed restoration effort to rehabilitate the stream system, introduce better management, and control runoff from additional urban surfaces in the County. This effort is the cornerstone of the County's MS4 stormwater permit.
Specific watershed restoration initiatives include:
- Stream restoration: Physically stabilizing streams and revitalizing stream ecosystems, which have been damaged by urban stormwater runoff.
- Stormwater pond retrofits: Expanding the capacity of and retrofitting stormwater ponds, which receive the large "first flush" of runoff that comes off city streets during rainfall events.
- Environmental Site Design/Low-impact Development: Integrating stormwater management into site design by using smaller, more localized controls that help runoff to soak in and treat it within the footprint of the urban site rather than conveying it (like a waste product) to regional waterways.
The County's built environment includes historical development as well as new development, so it takes all three restoration techniques together to:
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The Problem of Stream Damage
Over the years, many streams in the County's historically urban areas have received fast-flowing, highly erosive urban stormwater runoff from impervious surfaces such as roads, concrete, pavements, parking lots, and rooftops. During development in the past, there were few requirements to safeguard the streams, which received runoff and absorbed much of the stormwater damage.
Streams are fragile systems, and often they are unable to withstand the cumulative impacts of prolonged urbanization.
Learn more about common stream damage resulting from stormwater, which includes:
- Structural damage to streams. Channel and banks are destroyed, affecting the habitat available for biological life in the streams.
- In-stream pollution. Stormwater picks up and carries trash and debris, as well as chemical pollutants such as petrochemicals from vehicles and nutrients from lawn care.
- Improperly functioning aquatic ecosystems. Fish, amphibians, and insects are often unable to survive or reproduce in polluted conditions.
- Lack of forested stream buffers. Areas along streams lack good vegetation to retard pollution and erosion.
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