WINDHAM – The 100-year-old Dundee Dam, the largest of seven dams along the Presumpscot River, is getting some needed attention this summer.

Before heavy rain inundated the region two weeks ago, construction workers from Cianbro Corp. had been working at the dam, owned and operated by Sappi Fine Paper in Westbrook, since May 8. Once waters recede, the work will continue until a projected completion date sometime in September.

The work is necessary, says Brad Goulet, manager of hydrofacilities for Sappi, since a routine examination in 2010 indicated deteriorating concrete in the five vertical buttresses that hold back the wall of the 42-foot-high dam.

In place since construction in 1913, the steel-reinforced concrete buttresses are crucial to the structural integrity of the dam, Goulet said. They are 3 feet wide and range in depth from about 20 feet at their base to about 4 feet at their highest point near the top of the dam.

While the work is routine, and should allow another 20 to 25 years of use before needing further attention, the project is impacting local residents who live along the shore of Dundee Pond, which is the second largest impoundment of water along the Presumpscot River. Only Sebago Lake is larger.

While construction takes place, users of the town of Windham-owned Dundee Park and other residential users will experience lower-than-usual water levels. Goulet said the stretch above the dam is being lowered by 4 feet to prevent flash floods from harming workers, who are operating machinery below the dam. And depending on topography, some pond dwellers will lose dock access altogether through the summer.

Project necessity

With Dundee Dam holding back millions of gallons of water, Goulet said, Sappi is taking action now before the deterioration worsens. Some spalling of concrete, which, Goulet, said is due to the natural freeze-thaw cycle, was observed in 2008, but at that point was considered cosmetic. Last year, inspectors found the deterioration had gotten to a point where replacement was warranted, especially since the dam is considered by the federal government as a “highest risk” dam, meaning property and loss of life could result downstream if catastrophic dam failure occurred.

“Every five years [a third party] conducts very comprehensive inspections, which we call a Part 12. When we did the last Part 12, in 2011, we found there was some erosion in the concrete buttresses that had accelerated from the previous inspection,” Goulet said. “It’s certainly not the Grand Coulee Dam, but with respect to inspection criteria, safety factors, inspection frequency, we basically follow all the same guidelines as the Grand Coulee Dam does.”

Goulet said river water and debris passes between the buttresses, which result in the chipping and cupping where the water passes through.

“As we look at sluicing water through these areas, there’s quite a bit of erosive forces on the concrete. So we saw these piers were cupping at their base, they were thinning down at the bottom more so than at the top. It is a normal thing, but you have to stop it,” Goulet said.

Goulet said Sappi, which specializes in manufacturing coated paper at its Westbrook plant, operates six of the seven dams along the Presumpscot. Each of the dams runs a generating station, which powers the Sappi plant in Westbrook. Excess power not used by Sappi is sold to Central Maine Power.

Project delay

The weather, however, has not been cooperating with Goulet and Cianbro. Workers had built a temporary bridge and gravel roadway along part of the riverbed directly below the dam to allow heavy machinery and a crane access to the buttresses. While the bridge is unscathed, much of the roadway was swept downstream with the floods of the past two weeks.

But the rain also has meant about a month of high water for Dundee Pond users, some of whom were initially unhappy the work meant they’d lose four feet of water in the summertime.

Kim Doering, a Windham resident who owns, along with her mother, Joan Kirk, and extended family, eight lots on the Windham side of the pond stretching from just above the dam to Dundee Park, was initially upset Sappi chose to do the work in the summer. Doering and her children spend their summer days at the pond, and when the pond is low has no beach or dock access. Doering was mainly upset with lack of proper notification. She said she remembered a major dam restoration project in 1989 that drained Dundee Pond in the fall, after the summer recreational season.

After talking with Goulet and receiving a tour of the project, Doering said she understood the timing of the project, which must adhere to fisheries regulations adopted since 1989 that don’t allow Sappi to fully drain the river since it would deplete oxygen levels and kill fish.

A similar concern, according to Goulet, which necessitated the summer timetable, concerns eel migration, which takes place in the spring and fall. While Dundee Dam doesn’t have fish passage, it does have an eel elevator, Goulet said, which allows eels to swim upriver in the spring and downriver in the fall. Because of the natural and regulatory constraints, the summer construction season, Goulet said, was the best time to complete the required project.

While eels will be spared, it will ruin some residents’ summer fun, Doering’s family among them. Frustrated by lack of notice by Sappi, something that was corrected once officials were made aware of faulty addresses, Doering is accepting of the temporary situation.

“While at first I was pretty upset because it caught us off guard, I understand. Brad [Goulet] has been very good about trying to communicate information to us now, and obviously it needs to be fixed. Anyone seeing it would realize it needs to be fixed,” Doering said after receiving a tour of the project last week by Goulet.

While pond residents such as Doering are impacted by the drawdown, the alternative, Goulet said, would be that Sappi removes the deteriorating dam altogether, which would mean a permanent loss of water frontage, since the impoundment above the dam is much larger than what the river would provide naturally.

“If you were someone who lived on this impoundment and you were concerned about the fact that you lost this summer, which we’re very sensitive to, the fact that we’re making a big investment in the project preventing it from deteriorating means that the project is going to be operating for a long period of time,” Goulet said. “The alternative is you remove it, and we don’t want to remove it. If you remove it, there is no pond.”

Some on the pond have already taken precautions to ensure summertime access. Brian Ross, director of Windham Parks and Recreation, said the town-owned Dundee Park, located on the eastern shore of the pond, will maintain water access thanks to $2,500 worth of excavation work by Windham-based D&J Excavation, which graded the riverbank to allow a less severe access slope to the river for swimmers. The work was done in early June.

“Flows are high now because of the recent rains, but in two or three weeks they’ll be dropping again so we’ll be dealing with the lower water levels, so we’ll have to see how that works out,” Ross said. “But I think it’ll be all right. The work we did on the beach and the entryway to the water should work fine for young families.”

Ross has spoken with Goulet about the timetable for the project, and hopes the impact will be limited and, seeing the big picture, will mean many years of future Dundee Pond access.

“Hopefully they can get the work done this year and we’ll be back to normal from here on out for a while,” Ross said.

Brad Goulet, Sappi’s manager of hydroelectric facilities, explains how the Dundee Dam’s concrete buttresses behind him will be repaired once the water flow decreases. (Photo by Rich Obrey)