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Protecting Casco Bay from Stormwater

Friends of Casco Bay works hard to reduce stormwater pollution. Stormwater delivers some of the largest loads of pollution into Casco Bay. As stormwater flows over our roads, driveways, parking lots, and buildings, it collects a toxic slurry. Instead of filtering into the soil, water sheets off these impervious surfaces, picking up pesticides and fertilizers from lawns, exhaust and salt from roadways, pathogens from pet waste, and so much more. Stormwater carries this toxic mix into our rivers and streams, and ultimately into Casco Bay, causing a host of water quality problems.

While stormwater pollution is very difficult to eliminate because it is so diffuse, we are making progress on this threat by ensuring that the Clean Water Act permits that regulate stormwater are effectively implemented.

We have good news to share on this front. We maintained the strength of the permit that regulates stormwater discharged from large urban stormwater systems into our watershed through a successful appeal to the Maine Board of Environmental Protection.

You may remember that last year we celebrated that Maine’s new municipal separate storm sewer system (or, “MS4” as it is called) permit went into effect. For the first time, towns subject to the permit were required to develop LID ordinances to reduce pollution to the “maximum extent possible.”

Late last year, the municipalities subject to this permit submitted their draft ordinances to the Maine Department of Environmental Protection (DEP) for approval. To comply with the MS4 permit, the ordinances should have included nine mandatory LID strategies designed to reduce stormwater pollution from new construction and redevelopment. Although the drafts submitted by municipalities in our watershed did not contain all of these necessary elements, DEP approved the drafts.

To ensure the MS4 permit was properly implemented, we appealed DEP’s approval of the incomplete ordinances to the Board of Environmental Protection, a seven-member citizen board that provides independent decisions on the interpretation and enforcement of Maine’s environmental laws. This was our second appeal to the Board involving this MS4 permit, a decision that we did not take lightly but was needed to protect the Bay.

In November 2023, the Board of Environmental Protection agreed that DEP should not have approved the insufficient draft ordinances. The Board vacated the approvals and ordered DEP “to expeditiously set clear, specific, and measurable standards for the municipal LID ordinances.” The municipalities the order applies to include Biddeford, Cape Elizabeth, Cumberland, Falmouth, Freeport, Gorham, Portland, Saco, Scarborough,  South Portland, Westbrook, Windham, and Yarmouth.

We will continue to participate in the process to be certain the redrafted ordinances contain all of the necessary elements.