A Trout Brook culvert. Courtesy of Fred Dillon

Efforts to rehabilitate Trout Brook are underway through a culvert replacement project. The efforts are formed by a unity of individuals and organizations, including the South Portland Conservation Commission, Fred Dillon and Lacey Kremer from the Water Resource Protection Department, Stream Water Restoration Consultant Alex Abbott, Matt Craig of the Casco Bay Estuary Partnership, the Cape Elizabeth Land Trust, and the South Portland Land Trust.

“Watersheds can span municipal boundaries,” said Dillon, storm water coordinator. “We don’t do this ourselves; we do this with lots of partners.”

Trout Brook is designated as an impaired stream. This designation has been give to about 30 locations in the state, and tend to occur in heavily urbanized and developed areas such as South Portland. As a result, the city received funds from the Department of Environmental Protection to establish a watershed management plan in 2012.

The brook is designated as impaired by the DEP for multiple reasons: stream bank erosion, inadequate buffers, yard waste dumping, stream channel alteration, degraded aquatic habitat, decreased dissolved oxygen, elevated chlorides, and fish passage barriers.

One of the principal measures used to determine water standards are macroinvertebrates, which Dillon called the “canary in the coal mine.” Macroinvertebrates that spend so much of their life cycles in the stream are very useful indicators in determining if there are persistent pollutants or stressors. Some of these invertebrates are much more pollutant-intolerant than others. Ideally, Dillon said, you would find pollutant-intolerant insects in the stream, which would be indicative of good water quality. Not as many of these invertebrates are being found in the stream as the city and the DEP would like to see.

A lot of work has been done over the past 10 years to improve the brook. The most current effort is to upgrade/replace the culverts, which would improve fish passage.


“One of the significant recommendations in our Watershed Management plan is to identify areas that are real barriers to fish passage,” Dillon said. “And I guess the reason it’s called Trout Brook is because it actually used to support a native trout fishery. We have been releasing trout in Trout Brook for the past decade or so with the Portland Water District, which has a trout release program that we have been doing with middle school students for a long time.

“It definitely has trout, but they have a very limited range of motion because of these culverts that are restrictions or barriers to passage. This latest effort that we are involved with is to apply for a federal grant that would allow us to replace a bunch of culverts and thereby opening up more potential habitat to trout, so they can travel even further up into the watershed.”

The Water Resource Protection Department has recently received a grant from Casco Bay Estuary Partnership for just under $10,000 to study one of the key culvert crossings at Providence Road. The detailed analysis will determine if the city can install a much larger culvert of better grade, that would allow the passage of trout.

The department is adhering to “stream smart” principles, a set of practices used to make culverts mimic natural stream channels as much as possible despite a road being above them.

The department is submitting a concept proposal to the National Fish and Wildlife Association for a full engineering study for all of the culvert crossings in the area.

“If they decide to fund that, then that would be a really good indicator that they would then be willing to fund a major investment in infrastructure upgrades,” Dillon said.

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