Restoring natural filters
Situated at the southern end of a 2,500-acre watershed, the 14-acre Tanglewood Preserve — a park and stormwater treatment area in Lakeview, N.Y. — fell into disrepair because of budget shortfalls in the 1980s and 1990s. However, as water quality downstream from the wetlands deteriorated, Nassau County launched a restoration project to repair the damage.
Tanglewood Preserve was designed to collect and naturally treat stormwater runoff before it reached the Atlantic Ocean. The preserve includes wetlands, a red maple swamp and a 1-acre pond. At the north end of the preserve, a structure diverts water from Pines Brook into Tanglewood Brook, which meanders through the preserve, two sediment ponds and Tanglewood Pond before discharging back to Pines Brook. From there, water continues south to the tidal waters of the Atlantic Ocean.
During the county’s budget shortfalls, stormwater management components were not maintained, causing sediment to clog Pines Brook and erode its banks. In some areas, new vegetation grew, seriously impeding the hydraulic efficiency of the brook. The conditions also reduced the flow in Tanglewood Brook and starved Tanglewood Pond of a continuous flow that adversely affected water quality. In addition, because the park did not have a well-defined pathway around the Tanglewood Pond, park visitors damaged native vegetation and caused more erosion.
In September 2003, the county began a $1.2 million dollar project to restore aquatic habitats, install structures to protect downstream areas from the effects of stormwater runoff and beautify the preserve. Using capital funds and a grant from the U.S. Environmental Protection Agency, the project included construction of elements that limit sedimentation and erosion and routinely remove accumulated sediment.
To begin, the Pines Brook channel was de-silted, and a 6-inch diameter rip rap was installed to reduce erosion. Sedimentation ponds were cleaned and reshaped. Pond banks were stabilized with coir mesh and planted with native ornamental wetland vegetation to enhance aesthetics and remove harmful nutrients from the stormwater.
Tanglewood Pond was dredged, and 1,500 cubic yards of material was removed, deepening the pond by three feet. The pond bank was reshaped, and a four diffuser panel aeration system was installed to circulate and aerate the water, which will improve water quality and help maintain a warm-water habitat for fish that are stocked by the New York State Department of Environmental Conservation’s Bureau of Fisheries. Hundreds of native ornamental wetland plants of several species — such as Cardinal Flower, Pickerel Weed, White Water Lily, Narrowleaf Cattail and Duck Potato — were planted around the pond in coir mesh fabric.
A 6-foot-wide brick paver walkway was built to provide better access to the pond perimeter and to direct pedestrians away from sensitive areas along the pond fringe, minimizing erosion of the shoreline. Seating areas, a gazebo, scenic overlook areas, a new fishing platform and rustic bridge abutments were added for visitors. By July 2005, the finishing touches of the project — a wood-chip nature trail and low-profile wood bridges over Tanglewood Brook — were created to guide visitors through the natural red maple swamp.
To expand the use of the preserve, the county leased several historic buildings on the property to the locally based Center for Science, Teaching and Learning (CSTL) in exchange for rehabilitating the structures. Also, an adjacent assisted-living facility built a path from its facility to the preserve to give residents a place to stroll and enjoy the outdoors. “Utilizing state and federal grants to restore the beauty of this preserve and working with both the assisted living facility and CSTL is a perfect example of how a public-private partnership can work for the residents of this county at a minimal cost,” says Nassau County Executive Thomas Suozzi. “The Tanglewood Pond and Preserve now provides a habitat for wildlife, a center for learning as well as a refuge for the public.”
Brian Schneider, project manager for the Nassau County, N.Y., Department of Public Works