Stormwater is water from rainfall or snowmelt that flows across the ground and pavement. The water may seep into the ground, flow in ditches or streams, or enter the storm drain system. The storm drains are what you see at street corners or at low points on the sides of your streets. The storm drains then lead to a discharge point such an open channel or directly into one of the natural streams and creeks within Dougherty County.
The amount of impervious surface area (roads, parking lots, roofs) has increased significantly in recent years. This increase has a direct correlation to increased stormwater runoff volume, reduced groundwater recharge, and greater stream volumes. This altering of existing stream hydrology results in the erosion of stream banks, wider stream channels, excessive sediment transport, and the damaging of fish and wildlife habitat.
Additionally, when rainfall hits these hardened surfaces, it picks up pollutants. This is known as non-point source pollution, and it travels across the land’s surface eventually discharging into the Flint River and other Georgia waterways. Water that soaks into the soil is naturally filtered and cleaned. Water that flows on the surface of developed property picks up pollutants such as sediment, oil, pesticides, fertilizer, and bacteria from roads, parking areas, and properties where animals are kept. The effect of one property on the quality and quantity of stormwater runoff may seem insignificant, however, the cumulative impact from hundreds of thousands of properties across the state can negatively affect our water quality.
Keep in mind: much of the stormwater runoff that enters lakes, streams, and reservoirs, eventually becomes drinking water for downstream communities. This is one reason why protection water quality is so critical in Dougherty County.
The National Pollutant Discharge Elimination System (NPDES) Phase II permit from Georgia’s Environmental Protection Division mandates that Dougherty County create and maintain a stormwater management program. The Dougherty County Stormwater Management Program regulates stormwater discharges from the County’s Municipal Separate Storm Sewer System (MS4). The MS4 consists of streets, ditches, culverts, sidewalks, canals, holding ponds, etc.
As part of the NPDES Phase II Permit, The County is required to address six minimum control measures, which are as follows:
This picture demonstrates changes in runoff patterns due to increased impervious surfaces.