PORTLAND — Work to restore Capisic Pond is flowing, even if the water is not.
“Currently everything is on schedule and the work is being completed as (we) thought it would be,” Public Works project engineer Nathaniel Smith said Monday.
The long-awaited project to remove invasive plant species and cat tails that had clogged the open water in the city’s largest pond began last month when Stillwater-based Sargent Contracting blocked Capisic Brook upstream.
Smith said water flowing from the brook is now diverted with a dam made of sandbags built near the Rockland Avenue stormwater outflow. The brook flows to an existing storm drain, which empties below the dam on the other side of Capisic Street.
The city set aside $2.2 million to clear 4.5 acres of growth and restore open water, funded by 2015 and 2016 capital improvement bonds repaid through property tax revenues and sewer fees. Sargent’s bid of $1.46 million was the lowest of four received by the city.
Capisic Pond is fed by Capisic Brook, which flows to the Fore River. The largest work area is north of the Capisic Street bridge, but one area of invasive growth between the bridge and dam will also be cleared, Smith said.
Smith said the warm, dry weather has helped contractors stay on schedule, which requires them to be completely done by Nov. 30. That means new plantings will be in place and the site cleaned up and equipment will be gone by then; the dredging needs to be complete by Nov. 1.
A 2012 study for restoring Capisic Pond by engineering firm Woodard and Curran said the pond was last dredged in the 1950s. The engineers noted open water on the pond was reduced by about 70 percent, from 7.7 acres to fewer than 2 acres.
Capisic Pond has “experienced significant sedimentation with current open water only a fraction of historical dimensions,” the report said.
Smith said sediment removed from the pond bottom will be reused as a berm at a sporting club in Scarborough.
The headwaters of Capisic Brook are found north and west of the pond near Evergreen Cemetery, the intersections of Forest and Allen avenues, and beyond Warren Avenue and the Maine Turnpike.
“The pond receives runoff from a highly urbanized watershed,” the report said, although the completion of the Rockland Avenue outflow has eliminated some wastewater that flowed into the brook after heavy storms.
Woodard and Curran said the man-made pond dates to the 1600s; the dam south of the Capisic Street bridge was built in the 1950s and modified 20 years ago.
The new plantings are not only intended to block the growth of invasive species, they are intended to attract a wider diversity of species to the park, including more waterfowl.
The view from the bridge on Capisic Street in Portland of a drained and dredged Capisic Pond on Sept. 8. The pond restoration is expected to cost $740,000 less than the estimated $2.2 million.
The view from the Capisic Street bridge in Portland in July 2015 shows the extent of invasive species on open water in Capisic Pond.