They are WET LAND. They are squishy—you’re not swimming, but you’re not on terra firma either. Wetlands come in different flavors—they can be salty or fresh, upland or lowland, but the bottom line is that wetlands lie at the margin of water and land.
They are myriad, but we’ll mention 3 principal values: The first is Habitat. Lots of creatures live or spawn in wetlands. This means wetlands support commercial fisheries and recreation—both of which are big sources of revenue in Maryland.
Wetlands are valuable to those of us who live in low lying areas because of Flood Control. They provide a physical buffer against the sea. If you live in Havre de Grace for example, you may remember Isabel. A major reason why Isabel caused so much damage so far up the Bay is that bulkheads have replaced wetlands along a lot of shoreline. Instead of absorbing the storm surge as wetlands would have, bulkheads just passed it along. More recently, Katrina taught New Orleans a powerful lesson in the protection that wetlands afford coastal dwellers.
A third Value of a Wetland is Filtration. Whether you live in Aberdeen or North Harford, your wetlands hold water that runs off the land. They filter and clean the water before it enters the nearby stream, and ultimately the Chesapeake Bay. Wetlands also slow the water down, allowing it to seep into the ground to replenish ground water that we tap with our wells. If you are on a 70-foot well, and there are houses going in around you with wells to 300 feet, replenishment of ground water may be of interest to you.
Development affects wetlands when we fill, drain, dredge, and dam them. We use drain tiles, for example, to turn wetlands into arable, grazable land. Development affects wetlands when rain carries POLLUTANTS off the land (think golf courses in close proximity to streams, or the RV storage facility next to Winter’s Run, a source of water for Bel Air). Development affects wetlands via the quantity of STORM WATER RUN OFF. When roofs, parking lots and roads cover the earth, it can’t absorb water. When it rains, the water sheets off the impervious surface and floods the adjacent wetland. There’s more water than the wetland can process—so the water floods the adjacent stream, eroding its banks, and sending precious topsoil into the Bay. When a watershed has 10% impervious surface, water quality downstream plummets. When the wetland spills excess water, less of it is reabsorbed to replenish our ground water.
In so many ways, a better question would be, “Is there any way in which wetlands do not affect land use?” Water and land are intimately and inextricably intertwined—wetlands are at the interface. We often speak of wetlands as though they were passive, a barometer of how well we use the land. This is true, but it’s only half the story. Ultimately, wetlands decide how and whether we use the land. They decide land use when they protect us—or fail to—from the ravages of storms; they determine land use when they provide a breeding ground and refuge for creatures that feed us; they determine land use when they replenish and purify—or fail to—the water we drink. In short, if you think that we can develop the land without regard to wetlands, think again. Meanwhile, to get to know a wetland near you, just walk out the door and head downhill. Remember to wear your waterproof boots.
To mitigate is to lessen or moderate; to mitigate wetland loss is to allow development in wetlands and attempt to recreate a wetlands somewhere else. The replacement does not have to be within the watershed where wetlands are paved over. Developers may pay money to the County, called a fee-in-lieu, allowing them to build over top of the wetlands. The money collected is used for “Wetlands Restoration”.
Restoring a stream costs $100 to $200 for every linear foot. It costs $30,000 to $45,000 to restore an acre of lost wetlands. Design for wetlands mitigation is $135,000. The cost to the watershed when wetlands are destroyed may be immeasurable.