The groundbreaking on the Mountain Lakes Dam Rehabilitation project and dredging of the upper and lower lakes commenced on Tuesday at Mountain Lakes House. Engineer and Township Project Manager Deanna Stockton said that the $3 million contract requires the project to be complete by October 2011.
The dam restoration and the dredging is made possible through a partnership of local organizations and individuals, including the Township, Friends of Princeton Open Space (FOPOS), the Public Works Department, those involved in historic preservation, the Recreation Department, and an anonymous donor who provided the funding necessary to complete the work.
Compass Construction of New Egypt, N.J. and subcontractor Watts Restoration of Feasterville, Pa. are the construction companies that will work on the project.
Ms. Stockton characterized the changes as a safety improvement, explaining that both the upper and lower lakes would be drained, and the accumulated sediment would be removed. The upper dam will have reconstruction and rehabilitation work done on the concrete and stone, and the lower dam will be raised approximately 2.5 feet, she said. Installation of fish habitat structures in the lakes is also planned.
Trails around and leading up to the dam and lakes will be closed, and revised trail maps will be installed where the current maps are now, Ms. Stockton reported.
Naturalist Steve Hiltner of FOPOS called the changes a positive thing, saying that when the upper lake was created, it had a depth of seven feet, whereas currently the depth is six inches because of the buildup of sediment over time. To have the lake water deeper after the dredging will make it cooler, and a better habitat for fish, he noted, adding that there would be fewer algae at the site as well.
Mr. Hiltner explained the efficiency of this project is that they had to drain the lakes anyway, so why not dredge them at the same time?
When the lakes were created at the turn of the last century, they were clear of sediment, but over the past 100 years, dirt and silt have entered the waterway and accumulated at the lake bottom. Mr. Hiltner said that from what I hear, the sediment is clean enough that it can be hauled away and used in making topsoil.
Historic aspects of the dam will be preserved and restored as much as possible. Other improvements include extending the sewer line to Mountain Lakes House, which will eliminate the need for a septic field immediately above the upper lake.
Mountain Lakes Preserve was purchased by Princeton Township in 1987 in collaboration with FOPOS and an anonymous donor, and was added to the State and National Historic Register in 2007. The Princeton Ice Company, which functioned as an ice manufacturing site in the late 1800s and early 1900s, formerly occupied the area.
Mr. Hiltner explained that FOPOS is in charge of administering the conservation easement at Mountain Lakes, and has been working with Township engineering and public works staff on major decisions. When the Township needed to locate a staging area for the construction that required an acre of land to be cleared, Mr. Hiltner and others had a lot of input deciding which trees to save, and which could be cut down.