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Reducing a large source of pollution into the Bay

After a rainstorm, millions of gallons of polluted stormwater pour into Casco Bay.A wedge of dirty brown water floating on Casco Bay after a hard rain makes it is easy to understand that stormwater is one of the largest sources of pollution to our coastal waters. Stormwater can wash fertilizer, oil, pesticides, dirt, bacteria and other pollutants into our coastal waters. After one heavy rainstorm, we found a wedge of polluted stormwater 18 feet deep floating on top of seawater in Portland Harbor. Some of that polluted water flows into the Bay through storm drains, pipes, and ditches maintained by municipalities.

Over the next five years, many of the larger municipalities in the Casco Bay watershed will try to significantly reduce stormwater pollution. The Maine Department of Environmental Protection issues a new permit every five years to regulate pollution from municipal separate storm sewer systems. In each new permit cycle, the intent is to make communities more effective at reducing stormwater pollution.

Casco Baykeeper Ivy Frignoca is especially excited about two new provisions in the draft permit that regulates pollution from municipal separate storm sewer systems—MS4s for short.

Says Ivy, “Under the proposed permit, municipalities must test their stormwater outfalls for bacteria and other pollutants—and if found, they must trace them back to the source and work to eliminate the pollutants. Second, if a stormwater system discharges into an urban impaired stream listed in the permit, the municipality must identify ways it will reduce pollution, both through structural changes to treat stormwater and nonstructural changes, which could include adoption of an ordinance to restrict and reduce the use of fertilizers.”

Fred Dillon, South Portland Stormwater Program Coordinator, and Casco Baykeeper Ivy Frignoca test for bacteria in a municipal stormwater pipe in the Willard Beach neighborhood. [Photo taken last summer.]
Our Casco Baykeeper commented on many preliminary drafts of the new MS4 permit. She also met with state and town officials many times to discuss permit terms. Says Ivy, “We are gratified that our towns and cities worked with us and agreed to take these measures to improve and protect the waters we cherish and rely on.”

Fred Dillon, South Portland’s Stormwater Program Coordinator, reflects, “Ivy and Friends of Casco Bay were instrumental in helping MS4 communities step up our water resource protection efforts while also ensuring we have the adequate funding to do so.” South Portland is one of the communities around Casco Bay regulated under the general MS4 permit, along with Cape Elizabeth, Cumberland, Falmouth, Freeport, Portland, Scarborough, Westbrook, and Yarmouth.