In the 1980s, Evan Schulman, a financial services entrepreneur, and his wife, Glorianna Davenport, a co-founder of the Media Lab at MIT, acquired Tidmarsh farms in Manomet Village (Plymouth) Massachusetts to run as a single cranberry enterprise. When a more productive cranberry varietal made it possible to produce the fruit in upland fields, berries grown in wetlands became less competitive. At this point, Schulman and Davenport decided to place 225-acres of cranberry bogs under a permanent conservation easement restoring the cultivated land to its original purpose — as a wetland.
Tidmarsh is the largest wetland restoration undertaken in Massachusetts to date. It took three years and a massive effort that included engineers, hydrologists, and a collection of soil, botany, and wildlife scientists. At the center of the project is Alex Hackman, a restoration specialist with the Division of Ecological Restoration, Massachusetts Department of Fish and Game. Hackman is a soft-spoken man with gentle, but effective, powers of persuasion.
When laying out the approaches that could be taken, Hackman explained to the landowners, “If we’re taking a holistic approach, the dam that is creating the pond has to go because it links to everything else downstream.” This Davenport recalled, “was something the family needed time to think about since it would completely change the landscape.” In the end, the family took Hackman’s “holistic approach,” and the dam came down.
But from here it was all best guesses. This was literally new territory for the restoration team. Take the stream channel. “In most situations,” Hackman said, “we are hesitant to rebuild stream channels if nature can carve its own drainage path. When we have removed upstream pond dams there is usually a mudflat, and the river carves itself back to a channel again. If nature can shape it, let her do it.” The Tidmarsh project was different because the land is very flat with no stream power or groundwater to force the water to carve a new channel. With a great deal of humility, Hackman’s team did their best in estimating the shape of the original stream. The sinuosity of the stream one sees today at Tidmarsh was created in part by adding 3,000 huge stumps and logs that create little side arms and backwaters that help store water longer on the land and wildlife habitat.
The restoration took three years and a massive effort from a team of engineers, hydrologists, and a collection of soil, botany, and wildlife scientists. Heavy-earth moving equipment not only removed the pond dam but eight other earthen dams and berms, filled in drainage ditches, broke up over 100 acres of cranberry mat and constructed over 3.5 miles of new stream channel.
Hackman explains that although cranberry bogs are technically wetlands, “they don’t stay wetlands. They usually turn into drier pine forests.” The addition of sand cranberry farmers put down over the hundred or more years helped suppress pests and encourage vine growth, but it also “increased the elevation a few feet and then plants were no longer sitting in water but on dry sand.” Great for pine trees, not so good for wetland flora and fauna. Hackman describes a healthy wetland as “muck — nice, rich, dark, organic stinky mud.”
The ecology movement has drawn attention to the complex, dynamic relationships that make up each wetland system: as water filters that improve water quality, as buffers against floodwaters and storm surges, as a control against erosion along shorelines, and as a “food web” that feeds many species of fish, amphibians, shellfish, and insects that are also the source of food for birds and mammals. Scientists have also learned that wetlands play an important role in climate change by storing carbon within their plant communities and soil.
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The Arc of Change, From Wetland to Cranberry Field to Wetland