Stormwater Runoff
Stormwater runoff occurs when precipitation from rain or snow melt flows over the ground. As stormwater flows it picks up oils, salt, litter, sediment and other pollutants. Impervious areas prevent stormwater runoff from naturally soaking into the ground. These areas include:

• Buildings
• Driveways
• Parking lots
• Sidewalks
• Streets

As stormwater flows it picks up oils, salt, litter, sediment and other pollutants. This stormwater runoff can flow directly into the Town’s street storm drain collection system, or travel overland before it empties into water bodies like a Natick lake, stream, river, or wetland with little or no treatment to remove the pollutants that could be transporting. These are the same waterbodies we use for swimming, fishing, and providing public drinking water.

For more information, learn about the Nation Pollutant Discharge Elimination System (NPDES) stormwater definitions.

Why Be Concerned About Stormwater?
Stormwater runoff can have a number of impacts. As development and imperviousness increase in an area, the natural capacity of the soil and vegetation to infiltrate and take up rainfall decreases, and more rainfall becomes stormwater runoff. This can produce negative impacts such as erosion of land areas and stream banks, by causing or increasing flooding and also by carrying pollutants to surface waters.

As Natick grows, development increases. When more houses, roads and businesses are constructed, water has nowhere to go and can cause serious drainage, pollutant, and sanitation problems. Continued development causes:

• Erosion and sedimentation
• Impact to stream banks
• Increased imperviousness
• Increased pollutants
• Increased runoff

Stormwater Management Plan
The Environmental Protection Agency (EPA) has mandated that certain communities, such as Natick, must file for a permit under the Phase II National Pollutant Discharge Elimination System (NPDES) program. This program required communities such as Natick to create a Stormwater Master Plan that address 6 Minimum Control Measures.

These measures will be addressed by the town, implementing Best Management Practices (BMPs) appropriate for Natick’s community. The BMPs will commence according to the schedules provided in the NPDES Phase II Permit. The 6 minimum control measures for stormwater enhancements are as follows:

• Public Education and Outreach
• Public Involvement and Participation
• Illicit Discharge Detection and Elimination
• Construction Site Stormwater Runoff Control
• Post Construction Stormwater Runoff Control
• Good Housekeeping in Municipal Operations