The entrance to the new pool-and-weir fish ladder below the Bristol Mills Dam on Monday, Aug. 10. Mark Becker, of Nobleboro’s Becker Construction Inc., said the ladder will be complete by the beginning of winter. (Evan Houk photo)
Work on the new fish ladder at the Bristol Mills Dam is progressing and should be complete by the beginning of winter, according to the contractor.
Construction began in earnest the week of July 20 after being delayed slightly by a heavy rainstorm July 14.
“We got held up a little bit while we were trying to get the river to flush water,” said Mark Becker, of Becker Construction Inc.
The Nobleboro-based contractor has a contract with the town of Bristol to build the new fish ladder for an amount not to exceed $550,000, the sum approved by voters at the conclusion of annual town meeting on Aug. 4.
This will give Bristol Mills a fully functional fish ladder for alewives to ascend next spring, Becker said Monday, Aug. 10.
The town hopes to complete a second phase of the project, which will include external and cap masonry, landscaping, and construction of a bridge across the dam for pedestrian access, according to Bristol Town Administrator Chris Hall.
“The plan is to make a park and a footbridge like Damariscotta Mills, hopefully within the next year or two, but it all depends on the budget,” Hall said by phone Thursday, Aug. 6.
The old Denil-type fish ladder was removed by Hagar Enterprises Inc., of Damariscotta, on Friday, Aug. 7. Becker said the new pool-and-weir fish ladder will be similar to the one at Damariscotta Mills, although it will be much smaller.
A view of the progress on the new fish ladder below the Bristol Mills Dam on Monday, Aug. 10. Mark Becker, of Nobleboro’s Becker Construction Inc., said 14 more concrete pools have to be installed and stonework has to be done to complete the ladder by the beginning of winter. (Evan Houk photo)
Curt Orvis, a retired principal fishway engineer for the U.S. Fish and Wildlife Service, designed both pool-and-weir ladders. According to Hall, Orvis has a summer home in Vermont and has been regularly visiting Bristol to view the site and the work.
Becker said the new fish ladder will be built specifically for alewives, but will also help eels make the journey upstream to spawning grounds in the Pemaquid River watershed. The majority of the fish that migrate through Bristol Mills are alewives.
He said the new ladder will be much more efficient because it contains 9-inch weirs, or slots, for the fish to travel through to the next pool.
Once complete, Becker said, the fish ladder will contain 18 curved concrete pools with stonework inside to aid the fish in traveling upstream. There will a weir between each pool.
“The stone works to just dissipate the energy of the water because of all of the different surface area shapes — it slows the water down as it comes into each pool. It breaks it up, creates more oxygen, and creates bubbles and whatnot,” Becker said.
Peter Anderson, of the Bristol-based masonry subcontractor Natural Concepts Inc., will do the stonework. There have been many suitable stones donated for use in the fish ladder to save the town money, Becker said.
The entrance to the fish ladder has been moved downstream, away from the base of the Bristol Mills Dam — with a concrete channel that pushes more fish into the ladder.
“The problem before, with the entrance being (by the dam), you had a lot of fish that were going up to the face of the dam, because of the flow coming over the dam, and missing the entrance to the ladder. So, the idea is to funnel the fish to the entrance to the ladder,” Becker said.
The area where the rest of the Bristol Mills Fish Ladder will be built. (Evan Houk photo)
Becker said 14 more pools have to be laid out and constructed to complete the ladder. Once the concrete structures for all the pools are finished, the stonework will start.
Becker said that by adjusting the gates at the entrance to the fish ladder, town officials will be able to better control the water level and the flow of migrating fish.
“You can really get them moving by fiddling with the water a little bit,” Becker said.
Before work began on the fish ladder, some concrete repairs were done on the downstream side of the dam by Knowles Industrial Services Corp., of Gorham.
Hall said the repairs were needed to fill in holes and leaks with concrete before work on the new fish ladder could begin.
The company plans to return in late October to complete repairs to the other side of the dam and repair the footbridge that crosses the river on the north end of the swimming hole.
Voters approved $80,000 for the dam repairs at the conclusion of town meeting on Aug. 4.
Other recent work at the site included the installation of a metal handrail to assist swimmers in and out of the water by the slippery rocks on the side of the swimming hole next to the parking area. Bristol metalworker Adam Sprague installed the handrail July 22.
Hall said the swimming hole can reopen once there is no longer a need for water pumps on the construction site. He hopes it will open next week but said the town has not set a date. The swimming hole has been closed since the beginning of July.
