Water bodies come in many shapes and sizes. As EPA and the U.S. Army developed the Clean Water Rule, the agencies relied on the latest science to determine what water bodies should be protected. Streams and their wetlands that clearly have an impact on the health of downstream waters are protected by the rule. In particular regions of the country, there are unique water bodies that are also scientifically shown to influence the health of downstream waters and therefore may be protected under the Clean Water Rule. These unique water bodies are critical resources for the surrounding communities – for fishing, hunting, and recreation; for their ability to filter pollution to streams and rivers; and reduce flooding.
Prairie potholes are a complex of glacially formed wetlands, found from central Iowa through western Minnesota, eastern South Dakota, and North Dakota. Potholes accumulate and retain water, reducing floodwaters and filtering pollution before it goes downstream into nearby streams and rivers. Prairie potholes are also rich habitat for plants and wildlife. In particular they are vital to hunting in America, as they play host to 18 species of waterfowl. They are also are popular for birdwatching, with 96 species of songbirds, 36 species of waterbirds, 17 species of raptors and 5 species of upland game birds.
CAROLINA AND DELMARVA BAYS
Carolina and Delmarva bays are ponded wetlands along the Atlantic coastal plain from northern Florida to New Jersey. Carolina bays are most abundant in North Carolina and South Carolina, while those found in the Delmarva Peninsula are commonly referred to as Delmarva bays. Bays typically are close to each other or to streams, and connect to each other and to downstream waters in large rain events. Carolina bays and Delmarva bays filter out nitrogen, which reduces the pollution entering groundwater and flowing downstream. These bays are important nursery grounds for amphibians and reptiles.
Pocosins are evergreen shrub and tree-dominated landscapes that are found from Virginia to northern Florida, but mainly in North Carolina. Typically, there is no standing water present in these peat-accumulating wetlands, but a shallow water table leaves the soil saturated for much of the year. The slow movement of water through pocosins removes nutrient pollution and acidifies the water. This water is slowly released to downstream waters and estuaries, where it helps to maintain the proper salinity, nutrients, and acidity.
Vernal pools are shallow, seasonal wetlands that accumulate water during colder, wetter months and gradually dry up during warmer, drier months. In California they typically occur as complexes of pools, connected to each other and to seasonal streams. Vernal pools are rich in biodiversity and wildlife moves between the pool complexes and streams and other downstream waters. With climate change increasing the severity of drought in the West and specifically California, the protection of upstream water resources is even more essential.
COASTAL PRAIRIE WETLANDS
Along the Gulf of Mexico from western Louisiana to south Texas, freshwater wetlands occur as a mosaic of depressions, ridges, flats, and mounds on the landscape. Texas coastal prairie wetlands are locally abundant and function together to impact the health of downstream water bodies. Collectively as a complex, Texas coastal prairie wetlands can be connected to each other and contribute flow to downstream waters. Cumulatively, these wetlands control nutrient release levels and rates to downstream waters, as they capture, store, transform, and pulse releases of nutrients to those waters.