One of the most important functions of wetlands is to restore and maintain water quality. Wetlands upstream from the bay can filter sediments and remove pollutants from water before it reaches the bay itself. Wetlands are capable of removing up to 90 percent of nitrogen and 80 percent of phosphorus from water, as well as capturing particulate matter suspended in runoff.
The challenge becomes where to work within the 64,000-square-mile watershed to most effectively improve water quality through wetland restoration activity. In order to do our best with limited resources, DU developed the Chesapeake Bay Planning Network, which targets and ranks subwatersheds for restoration (see sidebar). Restoration activities in these subwatersheds will improve the quantity and quality of SAV for redheads and canvasbacks.
Focusing within these priority watersheds, biologists work with private and public landowners to restore and enhance wetlands, plant upland grass buffers, reforest riparian corridors, and improve coastal salt-marsh habitats, all of which improve water quality in the bay. DU restores previously converted wetlands to improve water quality and provide much-needed waterfowl and wildlife habitat. Riparian forests provide stream bank stabilization and act as buffers, filtering excess nutrients from runoff before it enters adjacent streams. Warm-season grass plantings perform a similar function. They filter sediment from surface runoff and uptake excess nutrients from groundwater. Grassland buffers are also effective in preventing topsoil erosion. Additionally, grass plantings provide habitat for waterfowl, upland game birds, and a variety of nongame species.