Unlike some other nearby communities, Watertown has separate sewer and stormwater drainage systems. The drain pipes do not go to Deer Island to be treated like sewage from your house is. Instead stormwater drainage is collected through catch basins, conveyed through drainage pipes, and then discharged into the Charles River, all with little to no treatment.
What is a catch basin?
There are over 3,200 catch basins in Watertown!
A catch basin, which is also known as a storm drain inlet or curb inlet, is a structure with an opening into the storm drain system. They include a grate or curb inlet at street level where stormwater enters the catch basin. But not just stormwater can enter the inlet. Oil and grease, car washing, pet waste, and any number of things can enter through the grate.
Catch basins do provide some pollution protection by preventing trash and other floatable materials from entering the drainage system. Most also contain sumps that allow larger sediments to settle in the basin. Nevertheless, catch basins provide little stormwater treatment.
Cleaning collected debris from a catch basin, part of annual stormwater maintenance performed by DPW contractor
Street sweeping does more than make our streets look nice, it removes trash and sediment from our roads before it can get into our drainage system
There are over 55 miles of drainage pipe in Watertown, ranging in size from 6-inches in diameter to over 6-feet! These pipes convey stormwater from our catch basins to our stormwater outfalls.
What is an outfall?
There are over 30 stormwater outfalls to the Charles River in Watertown. These outfalls discharge stormwater directly into the river.
Here is one outfall. It is located right along the Charles River Walk Way between the Charles River and Pleasant Street. All of the Town’s outfalls are labelled; this one is outfall #5, behind #304 Pleasant Street.
What can you do to help manage stormwater?
Planting rain gardens help because they infiltrate rain water before it enters into a storm drain. Another thing you can do is install a rain barrel to collect rainwater from your rooftops to use on your lawn or garden. This helps reduce stormwater runoff as well as reduce your water bill. If pet waste is left on the street, lawns or public parks it can wash away with water. This could contaminate our water. So just make sure to clean up after your pet.
The Town also offers a number of programs you can participate in to help improve stormwater in your neighborhood.
As part of the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) permitting program, the Town is required to take steps to reduce the impact of stormwater pollution. The Town of Watertown stormwater drainage system operates as a Municipal Separate Storm Sewer System (MS4) under this permit.
The Town’s program includes the following elements:
- Public Education
- Public Involvement
- Illicit Discharge Detection & Elimination (IDDE) link to other page
- Construction Runoff Control
- Post-construction Stormwater Management
- Pollution Prevention
You can view the annual updates to the Town’s program below:
Green infrastructure is a new approach to managing stormwater. Instead of flowing through downspouts, pipes, and other engineered systems into our catch basins and directly to our outfalls, green infrastructure uses vegetation, soils, and other natural elements to reduce the amount of stormwater and stormwater pollutants.