Wetland Assessment Criteria 19 



resource evaluations is well-developed, although many habitat evaluation 

 methodologies are based on various assumptions due to current gaps in 

 knowledge on wildlife habitat requirements. The Service's Habitat 

 Evaluation Procedure (HEP), which is based on a numerical rating of 

 habitat quality, is the most comprehensive methodology for quantifying 

 fish and wildlife resource values (U.S. Fish and Wildlife Service, 1980). 



High fish and wildlife resource values (biological or socioeconomic) for 

 wetlands are often associated with such factors as diverse species 

 composition; abundant wildlife numbers or populations; presence of 

 species, populations or habitats of special importance or concern; and/or 

 satisfaction of habitat requirements for those species with specialized 

 habitat or occupying outer extensions of their range. Large, diverse 

 wetlands, hydrologically connected to other wetlands, are likely to have 

 high wildlife resource values since they meet the living requirements of 

 more species. Wetlands with an irregular wetlands-open water edge and 

 intermixture of open water and wetland vegetation are more likely to 

 provide diverse food and cover conditions supporting more wildlife. 



c Hydrologic 



Hydrologic functions of wetlands include surface and groundwater 

 recharge and discharge, water quality, flood water conveyance and 

 storage, and shoreline and erosion protection. Most wetland functions 

 are related to the presence, quantity, quality and movement of water in 

 wetlands (Carter et al., 1979). In general, the hydrologic functional 

 values of wetlands are not well understood and the state-of-the-art is 

 poorly developed (Lonard et al., 1981); this is because wetlands are among 

 the most difficult hydrologic environments to assess (Sather and Smith, 

 1984). Additional research and field testing are needed to correct this 

 deficiency. Wetlands assessment techniques for hydrological functions 

 are limited or poorly developed. 



(i) Surface and Groundwater Supply 



The groundwater discharge function of wetlands (i.e., movement of 

 groundwater into surface water, e.g., springs) is recognized as being 

 more important than the groundwater recharge function (i.e., movement 

 of surface water into groundwater aquifers). Most wetlands are areas of 

 groundwater discharge with some providing water for public uses. Many 

 researchers believe that most wetlands do not function as groundwater 

 recharge sites (Carter et al., 1979). Some exceptions include depressional 

 wetlands like cypress domes in Florida and prairie potholes in the 

 Dakotas (Lissey, 1971). In urban areas, the pumping of municipal wells 

 may draw water from streams and adjacent wetlands and induce 

 groundwater recharge in wetlands (Tiner, 1985). Seasonal wetlands are 

 more likely to perform a recharge function than are permanent or semi- 

 permanent wetlands (Reppert et al., 1979). Recharge is important for 



National Wetlands Priority Conservation Plan 



