What Is a Wetland Functional Assessment?
Wetlands perform many ecological functions that have value to society. These functions (sometimes called ecological services) include groundwater recharge, storm water retention, stream bank stabilization, and fish and wildlife habitat. The USFWS’s (United States Fish and Wildlife Service) LLWW (Landform, Landscape, Waterbody, Water Flow Path) classification system is used to describe the physiographic context within which wetlands, as mapped by the NWI (National Wetland Inventory) and other systems, are located.
A wetland located within a riverine floodplain may likely provide functions in stormwater retention, stream bank stabilization, and fish and wildlife habitat. According to LLWW, this wetland is located in a lotic (riverine) landscape position, has a basin (depressional) landform, and is in a through-flow area where surface water may flow for some time each year or during high water events. The LLWW and NWI systems, called NWIPlus when used together, provide land managers and other interested parties with an overview of wetland distribution and the types of wetland functions across large areas. Wetlands could also be "ranked" according to their potential to provide a given function, helping managers understand where wetlands are performing particular functions and at what level (moderate or high). This information may be useful for determining what current wetlands might be of high priority for preservation.