Proper Functioning Condition - Lentic riparian-wetland areas are func-tioning properly when adequate vegetation, landform, or debris is present to:dissipate energies associated with wind action, wave action, and overlandflow from adjacent sites, thereby reducing erosion and improving waterquality; filter sediment and aid floodplain development; improve flood-waterretention and ground-water recharge; develop root masses that stabilizeislands and shoreline features against cutting action; restrict water percola-tion; develop diverse ponding characteristics to provide the habitat and thewater depth, duration, and temperature necessary for fish production, water-bird breeding, and other uses; and support greater biodiversity.

Toassess the condition of a riparian-wetland area, there must be a gauge to measureagainst. The definition of PFC in TR 1737-9 and TR 1737-15 establishes the gaugefor assessing lotic systems. This definition has to be adjusted for lentic systemsbecause they are affected by wind and wave energies or overland flow energiesversus high flow events, and they typically have a restrictive layer (e.g., geologicstructure/soil material/permafrost/manmade restrictive layer) that limits water perco-lation and maintains the site:

The Bureau of Land Management (BLM), the Fish and Wildlife Service (FWS), andthe Natural Resources Conservation Service (NRCS), formerly the Soil ConservationService, worked together to develop the PFC method. The methodology forassessing the condition of running water (lotic) systems is presented in BLMTechnical Reference (TR) 1737-9, Process for Assessing Proper FunctioningCondition (Prichard et al. 1993), and the methodology for standing water (lentic)systems is presented in TR 1737-11, Process for Assessing Proper FunctioningCondition for Lentic Riparian-Wetland Areas (Prichard et al. 1994).