A GIS-based score system for siting and sizing of created or restored wetlands: Two case studies

Water bodies are impacted by watershed loads in terms of nutrients and xenobiotics. This impact impairs the designated uses of the water body. Often preventive actions and end-of-pipe treatments do not reach the acceptable load to ensure the water quality standard in the water body. Wetlands are suitable tools for improving the self-purification capacity of a water system and can be used as a tool to reduce pollutant loads in a river network. This paper presents a methodology for the Siting and Sizing of created or restored wetlands at the watershed level, based on Geographical Information Systems (GIS) technique and estimations of wetland required area. The final outputs of the methodology are a Land Score System for Siting and a first rough estimation for the Sizing. The combination of these two elements is expected to be useful as a planning tool for watershed management and wetland planning. In order to assess the reliability of the procedure two very different case-studies are considered.