Buddy never saw the point of extending marshland. “It’s so much easier to find my ball on sand or mud than in that eelgrass stuff!”
What other climate protections do we see being created as we walk around town? We’ve noted stuff like sandbags, permeable pavements, new shade trees, removable flood walls, drought-tolerant lawns in recent ClimateDog letters.
What if we came across this scene?
If we ask them what they’re doing out there on the marsh, they’ll tell us . . .
We’re planting seagrass.
Increasingly strong storms, caused by climate change, are creating bigger waves which can quickly churn weak marshland into mud flats, making it easier for the waves to flood low-lying areas of the land behind the marsh. This can happen whether it’s the seashore or inland lakes and rivers. The leaves of eelgrass slow the motion of wind-driven water, and its extensive roots are good at holding a marsh together in the face of such waves, resisting erosion and minimizing shoreline flooding.
We’re filling ditches.
It’s not obvious, but filling up those ditches that have been dredged over the years to drain the wetlands actually helps defend us from climate change.
Ditches in marshland make it easier for waves to erode the soil and degrade the wetland.
Marshes and swamps are significant carbon sinks. Refilling ditches slows drainage and helps keep the marshland wet, preventing the exposure and decomposition of carbon-rich soil.
Despite being a carbon sink, a wetland can produce and release methane, a potent greenhouse gas. Refilling ditches reduces the oxygen in the soil, inhibiting the production and release of methane.
There’s lots of other care we can give our wetlands that will help protect the community from climate change. Constructing berms to contain floodwater, removing weeds that degrade the wetland, installing water control structures, or removing pipes, culverts or clay drainage tiles all help preserve the marshland.
What does it cost?
That party of workers out on the marsh suggests that planting seagrass is cheap, but costs actually run between $33,000 and $80,000 per acre, slightly lower if lots of volunteers are involved and well-managed. One cost is finding compatible soil to fill the ditches; often this needs to be dredged from nearby rivers, lakes, or channels.
Then the marsh has to be maintained. When all costs are included over the life of the project, it can cost up to $330,000 per acre.
These costs are more than repaid if the restored eelgrass meadows reduce flooding of nearby properties.
What we can do
There’s no national list of active wetlands restoration projects, but they’re not hard to find if we search for “wetland restoration near me,” maybe substituting “eelgrass,” “seagrass,” “saltmarsh,” or “marshland” into the search.
Buddy wasn’t around when I last planted eelgrass, but I remember it as a pleasant way to protect against local flooding - probably more fun than repaving our driveway, stacking a row of sandbags, or watching a temporary flood wall being installed.
LEARN, THINK, ACT
A mystery: “Cause and Cure for Ailing Wetlands” New York Times
What is often overlooked is the joy and sense of purpose that comes from being a volunteer in these kind of projects. Here in the UK we have a large and growing number of people involved in rewilding projects and we can see with our own eyes how species are returning to the evolving environments. The rewilding projects not only improve improved habitats for otherwise shrinking species lists but also act as carbon sinks (peat particularly) as well, of course, as holding water in times of flooding, as we have had this winter.
Always learning something new from you.