stormwater collaborative

What is stormwater pollution?

The Mystic River Watershed Association (MyRWA) has convened the Mystic River Stormwater Collaborative, a group of 13 towns and cities in the watershed dedicated to the common goal of reducing stormwater pollution, the primary source of water pollution today.

Stormwater pollution occurs when rain or snowmelt washes pollutants such as oil, fertilizers, pet waste and trash over land and into the nearest catch basin, which flows directly to the nearest water body.

As is required by the Environmental Protection Agency, municipalities are working to reduce the amount of pollutants that enter our water. One way they do this is through educating residents, businesses, developers and industry leaders in their communities on how we all can reduce stormwater pollution. MyRWA supports these efforts by creating monthly educational materials for the municipalities to disseminate.

The materials we create—social media posts, videos, brochures, flyers, press releases and educational curriculum—aim to raise public awareness about stormwater pollution and inspire stewardship.

Members of the Stormwater Collaborative

Arlington, Cambridge, Chelsea, Everett, Lexington, Medford, Reading, Revere, Somerville, Wakefield, Watertown, Winchester, and Woburn.

Monthly Clean Water Tips


Nurture your plants while protecting your rivers, lakes, and streams!

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When it rains, the water washes fertilizer and other pollutants from our lawns over our driveways, sidewalks, and roads, into our storm drains where it flows directly - and untreated - into our rivers, lakes, and streams.

Phosphorus - commonly found in fertilizers - can cause toxic algae blooms and fish kill. Under Massachusetts law, you can only apply fertilizer with phosphorus if a soil test shows that phosphorus is needed or during the first growing season for a newly established lawn.

Trying to figure out how to take care of your plants while also protecting our water? Consider the following tips:

  • Test your soil and apply fertilizers only as needed

  • Use Phosphorus-free fertilizers (the middle number is “0”)

  • Use slow-acting fertilizers

  • Follow instructions and do not over-fertilize

  • Do not apply fertilizer before a rainstorm

  • Leave grass clippings and add compost to your garden and lawn


Low Impact Development: Improve aesthetics while keeping our rivers, lakes, and streams clean!

During storms, rain runs over our driveways, sidewalks, and roads - picking up pollutants along the way. This water flows into storm drains and directly into our water bodies, causing water pollution. Low impact development (LID) is a set of building practices that mimic nature’s natural processes to keep rain water on site, thereby improving aesthetics while reducing water pollution in our streams, rivers, and lakes. Examples of LID include:

Rain gardens and bioretention facilities

A rain garden (or bioretention area)  is a depressed area in the landscape filled with sandy soil, topped with a thick layer of mulch, and planted with dense vegetation that collects rain water from a roof, parking lot, driveway, or street and allows it to soak into the ground, filtering pollutants and recharging groundwater.  rRain gardens and bioretention areas can be used in parking lot islands, median strips, and traffic islands. They can be incorporated in new construction or retrofitted into existing sites.

These rain gardens not only keep pollutants out of the water we fish, swim, and boat in, but they are a cost effective way of improving aesthetics.

Permeable Pavement

Permeable (or porous) paving is a replacement for asphalt and concrete which allows water to infiltrate into the ground below, filtering pollutants along the way. Examples of permeable paving include: pervious asphalt, pervious concrete, interlocking pavers, and plastic grid pavers. Permeable paving can also reduce the need for road salt and reduce construction costs for residential and commercial development by reducing the need for some conventional drainage features.

Rain Barrels

Disconnect your downspout and hook up a rain barrel! Not only will this keep rain water from washing pollutants into our waterways, but it will allow you to water your plants with rain water, saving money.

In addition to beautifying our cities and keeping our water clean, low impact development can also:

  • Reduce the need for and wear on traditional stormwater infrastructure

  • Muffle noise

  • Mitigate "urban heat island" effects by cooling and humidifying air

  • Absorb dust and smog as well as other contaminants from the air and rain

  • Provide habitat for wildlife including birds, butterflies, and insects.


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Keep our rivers, lakes, ponds, and streams clean—Use de-icer smartly and sparingly!
When the snow melts, do you ever wonder where all that salt and deicer goes? You guessed it! It flows over our driveways, sidewalks, and roads, into the nearest catch basin, and directly (untreated!) into our waterways.

What’s wrong with salt, sand, and deicer in our water?

SALT in our water is not good for plants, wildlife, or people. Birds can mistake salt crystals for food, eating them and getting sick. Salt can be toxic to fish and others in aquatic systems. Salt is not good for our plants, and in many wetlands salt-tolerant invasives are crowding out our native vegetation, which then affects the wildlife that lose their food sources. And of course salt in our water supplies is not good for us -- we all know that salt is linked to high blood pressure and heart disease. Salt includes sodium chloride, as well as calcium and magnesium chloride.

Some use SAND, and while it doesn’t carry chemicals into our waterways, it does clog catch basins and cause flooding. It can also carry other pollutants into our waterways. If used, excess sand should be swept up.

DE-ICER is a preferable alternative to both salt and sand, but it is still not perfect, and should be used smartly and sparingly. Deicers include Sodium or Potassium Acetate  and Calcium Magnesium Acetate.

What can YOU do to keep your pavement safe while also keeping your water clean?

  • Use de-icer (sodium acetate, potassium acetate, and calcium magnesium acetate) instead of salt (sodium chloride, calcium chloride, and magnesium chloride).

  • Shovel early and often. Remove as much snow and ice as you can, and only use de-icer on what you can’t take care of with a shovel.

  • Follow product instructions and only use as much de-icer as you need. More is not better.

  • For heavy snowfalls, shovel early and often to avoid the snow compacting and forming ice.

  • For wet snow or sleet and freezing rain, apply deicer product early on to prevent snow from bonding or ice from building up.


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Keep our rivers, lakes, ponds and streams clean—bag Your Leaves!

Bag or compost your leaves, but do not rake them into the street or dump them down storm drains! Blocking storm drains can cause flooding, and large amounts of leaves in our water can lead to an excess of decaying organic material in waterways.

Why do leaves cause water pollution?

Left on land, leaves decompose, feeding your plants and enriching your soil. But when large amounts of leaves wash off our lawns, down our driveways, into storm drains, and ultimately into our waterways— they release phosphorus and nitrogen contributing to water pollution.

These elevated levels of nutrients in our water:

  • Cause “blue-green algae,” or cyanobacteria blooms, which are toxic to both humans and wildlife and are considered a public health hazard

  • Kill fish through the depletion of oxygen in the water, called “eutrophication”

  • Cause the growth of large amounts of algae and invasive plants, choking up the waterway

What can YOU do?

Keep leaves out of the storm drain and your rivers, lakes, and ponds!

  • Bag your leaves for curbside pick-up.

  • Mix your leaves into your compost pile, creating a nutrient-rich fertilizer for your plants.

  • Use a mulching mower and create mulch from your leaves to use in flower beds.

Want to share online? Graphics are available! Banner can be found here and a copy of the photo can be found here.



Find more videos about stormwater runoff and about municipality efforts to reduce stormwater pollution on our YouTube channel.