WESTBROOK— Looking at the Presumpscot River since headwalls were removed from the dam, observers may notice changes in water levels and water flow.

University of Southern Maine Professor Theo Willis says over the next few years, people may notice some changes in wildlife populations, as well.

Talks about removing the dam for the benefit of wildlife began over 20 years ago, but was reinforced in 2006 when the U.S. Supreme Court upheld the Maine Department of Environmental Protection’s ability to require fish passage and minimum water flow standards around the Presumpscot River dams – then owned by S.D. Warren Co. – as part of water quality certifications required for federal relicensing.

After years of negotiations, the city of Westbrook and Sappi, the current owners, were able to come to an agreement to remove the dam to benefit Westbrook by means of wildlife and tourism, which was approved by federal regulators this April.

Work to remove the headwalls of the dam began around July 15, when changes in the water flow were most noticeable. Sappi is continuing to remove pieces of the dams while preparing to install a natural fish ladder sometime this month, as well as removing an existing powerhouse. Work is expected to wrap up as early as 2020. Sappi has to install a fish-counting facility by the river that has to be operational and running by 2024.

Bodies of water are nearly unpredictable with all of the different factors and shapes they take, but Theo Willis, a professor at the University of Southern Maine with a doctorate in the study of bodies of freshwater and oceanography from the Center for Limnology at the University of Wisconsin-Madison, believes that people will possibly notice changes as the river gets restored to a condition it has not been in since the 1800s.

“This is a small section of the 20-mile river that at one point had nine to 10 dams on it. It was essentially broken into 2-mile chunks. We are taking this one chunk out with fish passage, so this is the furthest up (the river) a fish has been able to get for nearly 300 years,” Willis said.

Through his years of study, Willis has developed a specific interest in Maine anadromous fish, fish that migrate upriver from the sea to spawn. Many factors play into how the river may change with the dams out, including how the channel of the river physically changes with the new flow, which in turn may dictate which fish populations do well without the dam.

“The head pond is mostly mud, so what happens is water hits the dam, as it slows, it drops the sediment it’s carrying into the water then goes over the dam and picks up some more velocity and drops more sediment downstream. There could be some channel changes in terms of depth and moving around some of that mud right below the dam, perhaps some redistribution there. It really depends on what the bottom is like. There are ledges under there people haven’t seen for a hundred years,” Willis said.

According to Willis, there will be a better idea of how the river itself changes after it is exposed to the first Spring rains, meaning it may take a few years to fully take what will be it’s new shape, making assumptions about wildlife even harder. Still, looking at the removal of the Kennebec dam and some other local ones, Willis has a good idea of what could happen.

“You will see some interesting flash water features. We may be able to take some cues from past dam removals on the Presumpscot. There have been big mayfly hatches in part because of the reshaping of the bottom of the river,” Willi said.

When the river gets reshaped, it could create more mud ruffles at the riverbed. Those ruffles store oxygen bubbles, which is where mayfly eggs are laid. More ruffles and more bubbles could lead to a mayfly explosion.

“Which brings in the birds. Upriver, you may see more herons and other birds. You may see some different fish, but (mayflies are) less appropriate for largemouth fish,” he said.

In regards to the fish, the more free-flowing river will be a bit cooler, which is more ideal for salmonids, the fish family that includes salmon and trout.

Another possibility is the discovery of shad, a fish believed to have been extinct from this area for years. When a dam in the Penobscot River was removed, they found a remnant population exploded back into a sizeable amount.

“(Shad) don’t like the fish ladder at Cumberland Mills, but you could still see that population build-up. They are good fish, good fishing and good eating,” Willis said.

Willis also noted that at certain times of the year, the fish ladder could be a genuine spectacle right in the heart of downtown.

“If you are at the fish ladder the right time of year it’s amazing. You have heron, gulls and eagles that are attracted to the runs,” Willis said. “When the salmon come upstream it attracts other fish so you may see striped bass up there, herons that eat the juveniles and adults. It will be a spectacle in the middle of an urban environment. We are making guesses though, each water project is different in a way,” Willis said.

While all of these changes are a bit upstream in the timeline, residents and visitors may have noticed some immediate changes in the look of the riverbanks.

According to Michael Shaughnessy, who lives on the Conant Homestead right off the river, immediately some changes in the water levels have occurred. Initially, the water levels lowered quite a bit, he said, but have since risen, but not to the former depth.

“All of what was covered by the river is now out, the foliage is really exploding and the trees are doing great,” Shaughnessy said.

Shaughnessy, who often canoes the river, has noticed more rock formations and a small, sunken boat in river corridor behind his property.

“Looking out you can see these two rock formations which were entirely underwater, so it’s cool to go around and look at what’s new, so to speak,” he said. “I have noticed the river has a lot of natural springs, too. They are small, but you will be canoeing and hear them before you see them, but they are like little jet streams of water, it’s pretty cool.”

Beavers have been a bit more active and notable on the river as well, having to change their forts around to accommodate the sudden changes in the water level, Shaughnessy said. Willis noted that without any real predators in Maine anymore, Beavers are definitely more notable, but are too small to dam the river themselves, aside from making a few small forts here and there.

“The reality is that there is an ecosystem around beavers. Beavers make meadows, they are hunted by wolves bobcats and mountain lions which we don’t have in southern Maine anymore so that system is out of whack anyhow,” Willis said. “Right now we are working on Highland Lake, or Duck Pond, and that is one of the highest densities of beaver of any stream in the area because there are no predators. Will you see beavers moving around? Sure, the river is too big for beavers building dams across it, but you will have some try so that kind of wildlife watching is possible with that empty space. You could possibly even see them from (Saccarappa) park.”

Currently, Sappi is working on removing the dam, with actual dam removal beginning last week. The installation of the fish ladder will begin this summer.

“This will be such a beautiful scene in the middle of downtown. The river is much healthier now and I love seeing the city embrace that,” Shaughnessy said. “Other mill towns have this thing where they may have rivers or dams and they are hidden or tucked away, but we will have this gorgeous river right here downtown, and that is incredible.”

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