What is stormwater?

Flooding on Washington Street, 2010


Stormwater Runoff

Developed areas like Braintree include many parking lots, buildings, roadways, and other hardened “impervious surfaces.” When it rains or when snow melts, water runs off impervious surfaces and picks up pet waste, oil, sand, fertilizers, and other pollutants.

Braintree’s existing stormwater infrastructure, which collects runoff from all over town, includes:

  • 3,887 storm drain inlets
  • More than 2,135 manholes
  • More than 98 miles of pipe
  • 261 discharge points

The water collected by this infrastructure discharges directly into local waterways, which themselves are a critical part of Braintree’s stormwater system. These are also the same waterways we use for fishing and swimming.

To learn more about stormwater and the substances it carries, watch the Stormwater 101 slideshow on the Think Blue Massachusetts website.

The Importance of Stormwater Management

Soil and vegetation in undeveloped areas soak up stormwater, which filters and replenishes groundwater while reducing the amount of stormwater runoff. However, as Braintree becomes more developed, the amount of impervious surface will increase. A greater amount of impervious surface leads to higher volumes of stormwater runoff, which increases the severity of the following issues:

  • Flooding
  • Erosion
  • Sedimentation
  • Increased amount of pollutants in waterways (chemicals, bacteria, litter, etc.)
  • Decreased biodiversity in aquatic species

Stormwater management helps mitigate the negative impacts of stormwater runoff. By creating a more resilient stormwater infrastructure, the Town of Braintree will enjoy the benefits of cleaner local water bodies and better flood control during rainfall events.

EPA MS4 Stormwater Program

The storm drain system in Braintree is regulated by the Environmental Protection Agency MS4 (Municipal Separate Storm Sewer System) permit program. The issuance of this permit means that residents, businesses, developers, and industrial facilities in Braintree shall only discharge clean stormwater. The Braintree Stormwater Division is responsible for ensuring that nothing enters the system that can pollute our streams, rivers, and lakes.

To learn more about Braintree’s Stormwater Program and the MS4 permit, view the DPW’s overview of the program.