Large sections of culvert that washed out from under Route 186 in Gouldsboro when torrential rains caused part of the road to collapse rest along a downstream creek bed in this June 2021 file photo. Credit: Bill Trotter / BDN

In early June of this year, a heavy rainstorm washed out part of Route 186 in Gouldsboro and multiple roads in western Washington County. Then in late October, another storm caused extensive water damage to roads in and around Camden and Rockport.

In each case inadequate drainage along and under roadways, caused in part by clogged culverts, helped aggravate flooding that caused sections of road to wash away in the deluge.

The issue of outdated culverts — a tunnel or open drain that carries water under a roadway — in Maine has come under greater scrutiny in recent years both because of increasingly heavier rainstorms and their impact on fish populations. As a result, conservation groups, municipalities and state agencies in Maine are focusing more on upgrading how rainwater is channeled under roadways as a way to mitigate the effects of climate change.

But it’s not just road washouts they are concerned with. Sarah Haggerty, a conservation biologist for Maine Audubon who leads the organization’s Stream Smart program, said roadside flooding caused by constricted or blocked culverts can cause environmental damage even when a road stays fully intact.

Flooding can sweep up trash that collects along roadways as well as spilled automotive fluids, remnants of de-icing agents and even plastic microparticles from tires, depositing it into waterways and downstream habitats.

And a washout often goes beyond the inconvenience it poses to motorists or nearby residents. Sections of road that end up in a stream bed can alter fish passage and pollute the stream, she said.

“All that fill you’re replacing is in the stream now,” Haggerty said. “You’re changing the bottom of the stream. You’re changing the way the stream actually functions.”

Sometimes, if the washout occurs on a private road, residents decide to simply put the road back the way it was, complete with the same piece of old drain pipe that washed downstream, because of the high cost of upgrading the stream crossing, she said. Then, if another heavy rain comes along and causes another washout, the process of the road eroding into the streambed plays out again.

Haggerty acknowledged that, for many people, the urge to repair the road as quickly as possible is strong, especially if it cuts them off from their house or creates a long, inconvenient detour for them to get to their destination. But, over time, such quick repairs exacerbate the problem and add to the eventual expense.

Reusing a culvert or replacing it with one the same size is only a short term fix that will have to be repeated, Haggerty said. A better fix is to install a bigger culvert or a small bridge to carry traffic over the drainage area. While those cost more in the short term, over time the costs will be cheaper since the work won’t have to be repeated.

The Maine Department of Transportation has a list of local projects aimed at fixing drainage problems before roads are washed away. In Bar Harbor, some downtown roadside drainage improvements along Route 3 and the replacement of a large culvert where Kittredge Brook runs under Route 102 near Somesville are earmarked. Bethany Leavitt, the town’s public works director, said culvert replacement projects also are on the town’s list of improvements to be made.

Leavitt, who started her job in Bar Harbor nearly two years ago, said she has tried to take a more empirical, proactive stance on addressing the town’s more urgent infrastructure needs, which include handling storms that dump heavier amounts of rain.

Where once the town would assume culverts were fine until they obviously weren’t, Leavitt said she is trying to use data to determine when they should be replaced.

“As we prepare for projects, which typically have been more conditions-driven, I’m hoping to use more of a data-driven approach,” Leavitt said. “We’ve just started discussions on planning for a more resilient system” for stormwater runoff.

She said the town’s roads crew is planning to replace several culverts along Sand Point Road in the coming year.

Jarod Farn-Guillette, director of the Hancock County Planning Commission, said that the issue of inadequate road drainage is not specific to coastal Maine, where offshore storms often bring heavy rainfalls. He noted the Maine Stream Habitat Viewer — an online interactive map maintained by a collaborative group of state and federal agencies, private businesses and non-governmental organizations — has hundreds if not thousands of colored dots in all developed parts of the state that show where streams have difficulty flowing under roads, usually because of blocked or insufficient culverts.

“There’s a number of them,” Farn-Guillette said. “There are several that are considered complete barriers.”

There are several roads noted on the Blue Hill Peninsula, for instance, he said. Other areas in eastern Maine that appear to have higher concentrations of blocked or potentially blocked stream crossings include Mount Desert Island, western Penobscot County, the Camden-Rockport area and the Moosehorn National Wildlife Refuge near Calais.

Farn-Guillette said that as part of his job, he helps local municipalities apply for matching funds from the Maine Department of Environmental Protection’s municipal stream crossing upgrade program, which provides funding of varying degrees for culvert replacement projects.

Municipal interest in the program “comes and goes,” he said, but the impact of heavier rains on Maine roads, many of which were designed decades ago, is not expected to fade. Every town in the state should be focused on upgrading their culverts before a storm comes along and gives them no choice, he said.

“I’d say everybody needs to do it,” he said.

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Bill Trotter

A news reporter in coastal Maine for more than 20 years, Bill Trotter writes about how the Atlantic Ocean and the state's iconic coastline help to shape the lives of coastal Maine residents and visitors....