TOPSHAM — The Board of Selectmen is looking into a three-part project geared toward mitigating groundwater drainage problems that have plagued the Bay Park neighborhood in recent years.
Snowden Consulting Engineers presented the results of its engineering study during the Board of Selectmen’s Oct. 1 meeting.
The firm started the project with a topographical survey and test bores around Bay Park, and surveyed residents about water problems like flooded basements. Snowden also held a public hearing in late August.
“We wanted to really take a holistic approach to this and … step back and think outside the box as to different ways we could hopefully solve these issues for the people as far as the groundwater levels,” the firm’s Boyd Snowden said.
The process of mitigation would optimally involve three components, he said, which together could cost about $480,000.
The levels of two ponds at the transfer station would each be lowered by about 4 feet in what he recommended as the initial project phase, which could cost about $123,000. A constant level would be established for those ponds.
“What we’re trying to do is just reroute the groundwater table,” Public Works Director Rob Pontau said. “The ponds aren’t what causes the water to flow towards Bay Park; there are some other high points in the entire groundwater system. But by lowering these ponds, we can create a draw-down, which will essentially cut off the water and make the water that flows from the high points, instead of flowing to Bay Park, want to flow towards the ponds. Then at the ponds it will be able to outlet. We’re changing the flow direction of the groundwater.”
The water currently flows from a high point near Foreside Road toward Middlesex Road across Bay Park, Pontau said. That flow would be rerouted toward the ponds. The water would outlet from the ponds into a ravine that leads to the Muddy River.
Another component, to cost about $236,000, would involve replacement of the under-drain system at Hunter Lane, as well as lowering it by a few feet and installing an 18-inch drain. The system would also have an outlet at a new location in order to gain nearly 2 feet in elevation.
A third component, at a cost of about $121,000, would be replacement of the under-drain line at Loon Drive, and to reverse its flow. It currently heads to Coot Lane and ultimately Bay Park Drive; it would be turned toward Hunter Lane. Snowden said many Loon Drive catch basins showed water levels over the top of the pipe.
“Reversing it will help give us a little slope, and make the water flow better,” Pontau said.
Completing the pond-lowering phase first will make installation of the lines in the other phases easier, he explained.
“You’re going to get some benefit by doing each of these components, but it’s the three combined that really take care of the issue for the residents of Bay Park,” Snowden said.
Selectmen asked Snowden for a finished product of the plan in hard copy to study, and are also waiting for a schedule for the total project.
Earlier in the meeting the board voted unanimously to install a sign in the small lot near the Swinging Bridge that will ban parking there between 10 p.m. and 5 a.m. Complaints from neighbors about late-night activity spurred the action.
Alex Lear can be reached at 373-9060 ext. 113 or firstname.lastname@example.org.