Strategic Bog Projects for Climate Resilience

The Coalition recently bought 42 acres of mostly retired cranberry bogs in Onset. This will become a coastal bog restoration project that can allow the salt marsh in Onset's Broad Cove to expand inland as sea level rise from climate change progresses. Purchases like this are part of a long-term view toward maximizing opportunities for healthy salt marshes in the future, as salt marshes provide a critical ecosystem for wildlife, coastal resilience and help ensure clean water throughout Buzzards Bay.

Nearby in Bourne, Puritan Bogs is another example of the Coalition looking to restore these strategically placed bogs in a way that will allow salt marsh to migrate in. Last month, Coalition staffers Evelyn Mortimer and Kate Ricketson were deliberately making their way through this overgrown mess in search of channels of mucky water. They donned chest-high waders and pulled back their hair in ponytails, which they tucked under hats.

They are meticulously surveying the site. This is their second surveying trip to the Bog, picking up where they left off last time. It’s fairly simple at first glance: record the elevation of the top of one side of the ditch, the middle of the ditch, and the top of the opposite side. They record a set of three elevations at intervals along the former irrigation ditches. “In a spot where the ditch changes considerably in width, depth, or direction, we need to record that so the mapping program has the most accurate measurements,” says Mortimer.

Back when it was a working bog, the cranberry farmer would keep the ditches clear and of similar dimensions throughout the bog. But nature has changed all that. Sides have caved in and sediment has gathered in various depths in the water. 

Usually when a bog is retired and slated immediately for restoration, engineers can understand ditch and channel depth at the bog through satellite images and a knowledge of how deep the farmer kept the them. But because decades have passed since these bogs stopped production and nature has taken its toll both in the channels and on land (plant and tree overgrowth obscure the satellite images), Mortimer and Rickets are forced to survey with boots on the ground—or waders in the muck.

So why are they surveying this land at all? Engineers will need a very precise topographical map of the channels so they know how much earth they will need to relocate into the ditches to bring them more to their natural shapes, allowing the influx of salt water to all reaches of the old bog and letting it thrive once again as a natural wetland.

As sea levels rise, salt marshes need gently sloped places to establish, and a restored cranberry bog adjacent to a tidal waterway can be the perfect location for that. This is climate adaptation in action.

And, for Ricketson and Mortimer, that means getting data. “Field work isn’t always glamorous, but it is critical to our work. For a restoration project to be successful, sometimes you just have to jump in and wade through the muck,” says Ricketson.