The Development of Landscape Analysis of Wetland Function (LAWF): a GIS-based Wetland Functional Assessment Tool.

The various functions performed by wetlands in the landscape and the associated impact on water quality–nutrient uptake and cycling, wildlife habitat, flood flow attenuation, contaminant binding, sediment retention, stream base flow maintenance–are well documented. Regulatory agencies require protection, preservation, and when impacts are unavoidable, mitigation of wetland systems. Traditionally, replacement of wetlands is done on a strict ratio of replacement to loss, without regard to functional losses associated with the destruction of particular wetlands. Crucial aspects related to the successful establishment of these systems include proper hydrology, landscape position, and appropriate soils. Using GIS-based tools, areas for successful wetland restoration and mitigation, along with storm water management facilities, can be identified and protected.Prince George's County, Maryland, USA, has developed a GIS-based, landscape-level functional assessment application in the ArcView environment. Based upon HGM and other functional assessment approaches, the tool will be used to site mitigation banking areas, locate rare wetland types for protection and preservation, and allow the impact of public works projects proposed by the County to be evaluated before execution. Excluding certain areas from consideration before going to the field for expensive on-site evaluations allows for efficient use of County resources and protection of wetland function in an integrated, watershed-based fashion.