A Bird's Eye View Of Cold Brook Preserve

 HARWICH – It will be a couple of months before the Robert Smith Cold Brook Preserve can be open to the public, with the finishing touches now being made to parking facilities, stormwater swales and the scenic overlook at the former cranberry bogs off Bank Street.

 But the year-long eco-restoration project has brought major changes to 49 acres of the 66-acre preserve, establishing four ponds to help remove nitrogen from groundwater flow; freeing the flow of Cold Brook, disrupted many years ago to direct water for cranberry production; and reclaiming wildlife habitat.

 “Everything is engineered and incredibly deliberate. It’s a very precise engineering project,” Harwich Conservation Trust President Tom Evans said during a tour of the restored habitat Aug. 29.

HCT owns the preserve and has been working with the town, the Massachusetts Division of Ecological Restoration and the U.S. Fish and Wildlife Service to return the fallow cranberry bogs to a natural marshland system. The inclusion of four ponds on the property is expected to remove nitrogen flowing through groundwater, improving the health of nutrient-impaired Saquatucket Harbor watershed.

What has happened in the preserve over the past year is transformative. Cold Brook has been extended by about a half mile and is flowing freely for the first time in a century.

“It really has become an oasis in the heart of Harwich Port,” said HCT Executive Director Michael Lach. 

 The ponds, each about three-quarters of an acre and six to eight feet deep, are retaining groundwater and allowing the natural process of attenuation to reduce nitrogen levels. The hills and marshland are accommodating a return of wildlife.

The trails remain closed, said Evans, but people really want them opened. There is a lot of interest in accessing the preserve, but the construction zone still has its complications, he said. 

The old asphalt from the previous parking lot that separates the preserve from the newly renovated former fire station has been removed and a new 25-space asphalt parking lot is being built outside the 100-foot buffer to wetlands. Stormwater filtration swales and handicapped accessible pathways leading into the scenic overlook are also planned. The trails will be opened in a couple of months when the parking lot is completed, Lach said.

Inter-fluve Inc. of Cambridge designed the restoration, which is completed. It includes a handicapped-accessible trail made of stabilized stone dust which provides a hard surface trail a half-mile long that accommodates wheelchairs, providing access for folks with physical disabilities and families with youngsters in strollers, said Lach. 

There are four wooden bridges that span sections of Cold Brook and natural loop trails for those seeking a longer walk through the wildlife habitat. Evans said the wildlife adjusted to the transition quickly. Workers were seeking deer and coyotes early in the morning. The grounds are changed to address the needs of varied species of wildlife. Two hills, said to have been there before the property was altered to accommodate cranberry bogs, have been restored.

There are three otters living in the first pond, Evans said, and a lot of dragonflies are returning to the area. The invasive species that infiltrated the cranberry bogs over the years have been buried beneath the reconstructed hills. The thought was it would be better to bury them than have them carted off site through Harwich Center in 18-wheeler trucks, he said.       

“We’re really trying to maintain the habitat for wildlife,” said Evans.

Traveling the natural trails one comes upon a 100-foot wooden bridge over Cold Brook and associated wetlands. This is an area that is subjected to tidal flow, especially during astronomically high tides and storm force conditions. Lach points to the side of the brook at the saltmarsh grass planted that is thriving. The wetlands will help diminish nitrogen generated by septic systems to the north of the preserve, he said. The greenery surrounding the bridge is a visible sign of the healthy transformation.

A large patch of cattails is growing near one of the ponds. Evans said during the restoration the equipment turned over a 100-year-old seed bank and the species contributing to the greenery surrounding the bridge have come from that seed bank. Much of the new growth in the preserve comes from that and other seed banks, he said.

Looking north from the bridge provides a clear look at pond four. There are slash piles of tree stumps and branches along the edge of the Cold Brook, placed there to hold the bank of the river and to provide shelter for fish making their way to the salt pond or accessing spawning headwaters in Grassy Pond.

Pond four is the recipient of tidal flow and the newly created water body is alive with activity. Loons, ducks, and laughing gulls could be seen on the water, and a spray of minnows ripple the surface. In pond three, a great blue heron waited cautiously while visitors passed. Just off the shore was a small island clustered with birch trees. Evans said a major effort was made to preserve the birch trees.

Old song bird nest boxes dot the woods that separate the preserve from several large houses skirting the oasis. Lach said the nests have been studied for a dozen years and HCT officials are anxious to see what changes occur next year.

“Next year we are expecting to see an increase in the number of bluebirds nesting there,” he said