4 minute read
Tidmarsh Farms Cranberry Bog
Plymouth, Massachusetts, United States
Carrying out the largest freshwater restoration in Massachusetts. In 2009, the owners of Tidmarsh Farms entered an agreement with the U.S. Department of Agriculture’s Wetlands Reserve Program to place nearly 80 hectares of cranberry bogs and degraded wetlands near the headwaters of Beaver Dam Brook into a conservation easement. The region had suffered from the effects of deforestation and draining since the seventeenth century, and cranberry farming practices had further impacted biodiversity, aquatic life, and local hydrology. The restoration process began by documenting the existing habitat and geomorphic conditions, then examining the possible wetland and stream restoration opportunities, and finally identifying the constraints and opportunities at the site. That analysis resulted in a concept design describing various restoration options for the bog complex, downstream channel, dam, and impoundment. In 2014, the project team decided on the final design: channel restoration, reestablishing hydrologic control, and native plant revegetation for the entire 80 hectares. Construction began in 2015 on 6000 meters of new stream channels, 100 hectares of fen and Atlantic white cedar bog restoration, sphagnum reintroduction, fish passage improvements, and the removal of the headwater dam. The final result is a thriving habitat, increased biodiversity, and a haven for birds, butterflies, and native wildflowers.
Article cover: The new meandering stream intersecting some of the former drainage ditches. (Photo by Inter-Fluve)
Producing Efficiencies
Economic shifts, climate change, and new farming techniques have resulted in farmers letting their cranberry farms go fallow around Massachusetts. This project models transforming abandoned cranberry farms to native stream and wetland ecosystems, restoring nonproductive land into valuable native habitat. There exist only a few known wetlands in the region not affected by the last 400 years of use, so the team had few real-world examples to draw on. The success of the Tidmarsh restoration will serve as a model for future projects and provide additional opportunities for scientific and academic research, design engineering, and permitting and monitoring.
Using Natural Processes
Constructing riffles in new stream channels and filling in and plugging perimeter and lateral ditches raised the water’s surface elevation in the retired cranberry bog, converting them to native stream and wetland ecosystems. The project team used thousands of pieces of large wood and tree stumps, many from adjacent forestland or from local entities looking to dispose of downed trees, to provide complexity in habitat conditions for fish and other aquatic organisms. By engineering microtopography into the landscape through a pit-and-mound design, the team naturally encouraged diversification in flora and fauna and made the habitat more resilient to climate change.
Broadening Benefits
The Massachusetts Audubon’s Nature Sanctuary and the Living Observatory demonstrate Plymouth’s emergence as a center for ecotourism and scientific inquiry and provide the same level of employment— perhaps even more—as when Tidmarsh was a working farm. The sanctuary and observatory engage the public and provide educational and academic inquiry opportunities while also providing a space for recreation and wildlife observation. The restored wetland also makes the region more resilient to climate change as the design will adjust with sea level rise.
Promoting Collaboration
The team collaborated with the Department of Agriculture’s Wetlands Reserve Program, the Massachusetts Division of Ecological Restoration, and with scientists from nearly a dozen academic institutions, including the University Massachusetts–Amherst’s Geosciences Department for their expertise in spring flows and stream temperatures and the Massachusetts Institute of Technology’s Media Lab for their expertise in remote-sensing operations. The Massachusetts Audubon purchased the site as a wildlife sanctuary and now provides trails, educational signs, and an educational center to encourage long-term research and monitoring.
