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Showing posts with label Hopkins Dam. Show all posts
Showing posts with label Hopkins Dam. Show all posts

Friday, March 31, 2023

Hopkins Dam key to erosion prevention on Little Sebago Lake

By Abby Wilson

Little Sebago Lake has many special features, including an outlet dam that regulates the water level to mitigate erosion and prevent lakeside property damage. Hopkins Dam is owned by the Little Sebago Lake Association and Rod Bernier has managed the dam since 1996.

Hopkins Dam was built on Little Sebago
Lake in 1890 and continues to regulate
water levels on the lake to prevent erosion
and mitigate water damage to lakeside
properties. PHOTO BY STAN PAUWELS  
As the dam keeper there, his basic role is to operate and maintain the dam, says Bernier, and his regular duties include checking water level and regulating outflow.

Hopkins Dam is an outlet dam, so Bernier pays careful attention to the water level because the state mandates that the lake be kept at a certain level from April 15 to October 15.

The dam keeper must also develop emergency plans with the state and Cumberland County Soil and Water Conservation District in case the dam fails.

The last time a dam failed on Little Sebago Lake was in 1861.

“After a period of heavy rain, it washed out everything between here and the ocean,” says Bernier. There were reports of the Presumpscot River flowing backwards due to flooding.

A new dam was built in 1890, and Bernier says it has “certainly stood and held to the test of time.”

The Hopkins Dam was purchased by the Little Sebago Lake Association in 1952 from the S.D. Warren Paper Mill for $2,500 plus $400 to cover surveying costs.

As a 501(c)(3) nonprofit, Little Sebago Lake Association can receive funding through donations. Memberships are not required from residents but annual donations have been able to cover most expenses including operation of the dam and water quality testing.

The association tests for water clarity and oxygen and with the help of students at Saint Joseph’s College, they also test for chlorophyll and phosphorous.

Lake Association President, Pam Wilkinson, says “membership has been great.” In fact, last year the gate mechanism needed an upgrade and $76,000 was raised. Lake side residents contributed largely to this project, as well as the towns of Gray and Windham.

This gate mechanism is very important for regulating the water level of the dam but is also key in allowing fish to pass through. There are no salmon species in Little Sebago Lake, so the dam does not have migrating fish, however, year-round, a small area (about 4 inches) is left open for freshwater fish to exit and go downstream.

There is a gauge installed on the face of the dam and Bernier must watch this gauge very closely. Ideally, the gauge remains at 0 during the summer. As of March 14, the gauge measured 19 inches below 0.

In the later winter months, water levels should be low to account for spring rain and snowmelt. Keeping the water level low in winter will prevent flooding and “preserve the shoreline so the ice doesn’t compromise it,” says Wilkinson. When ice melts, it tears the shoreline up as it retreats. This causes erosion of the banks and destruction of property.

The lake association has noticed changes due to climate change. When there is less spring rain or snowmelt and more summer droughts, it results in a low lake level and a higher water temperature. Also, sunlight reaches lower and plants grow where they shouldn’t.

A low lake level affects recreation. As the lake lowers, more bottom-dwelling glacially formed rocks are exposed and are often hit by boat propellers.

Wilkinson said, “Some summers residents tell me ‘that rock grew.’”

Bernier says that as dam keeper he gets many requests.

“People ask me to let water in and open the dam,” he said.

This is of course not possible since Hopkins Dam is an outlet dam and it only can let water out.

It can be tricky to predict these seasonal rain and snow events.

To account for climate change, it seems the dam could just let less water out but Bernier says, “We can’t take the chance with flooding and the number one concern is safety of people downflow, so even if summer levels are low, we can’t take the risk.”

The Little Sebago Lake Association’s mission is “To protect, restore, and improve our lake’s water quality and fragile ecosystem.” The lakeside residents are a huge help in this effort and Bernier says Little Sebago is a “beautiful lake and great community.” Wilkinson speaks of a large rock that many people enjoy jumping into the water from and says “It’s a right-of-passage.”

When Wilkinson asks for volunteers and donations for projects or just general support for the 30 miles of shoreline they manage, the people of Little Sebago Lake show that they care.

“The Little Sebago Lake community is such a special community. We do have people that are concerned and support us,” she said. “This is the way it should be. We have a mission and we hold true to that.”

To learn more about the Hopkins Dam and the Little Sebago Lake Association, visit littlesebagolake.com.<