Multiple-criteria decision making for integrated watershed management in the Ramian watershed, Golestan, Iran

This research has concentrated on the physical and socio-economic impacts of vegetation-based management scenarios targeting on flooding and soil erosion issues in the Ramian sub-watersheds. The Ramian watershed with an approximate area of 24000 ha is located in Golestan, Iran. For each sub-watershed, four biological actions (activities) and 16 management scenarios have been considered. Physical impacts have been studied using the SCS (Soil Conservation Service) hydrologic model and the EPM (Erosion Potential Method) model. Economic and social impacts have been evaluated using the cost/benefit analysis as well as the examination of the results of a social survey. Some physical, social, and economic indices were chosen and quantified. The indices then were standardised using the interval standardisation technique. Best scenarios were determined using a multiple-criteria decision making technique. To weight the indices, four perspectives were used. For the first three perspectives one of the physical, social and economic criteria were assigned higher weights while for the fourth perspective all criteria were given the same weight. Trade-off analysis of the results indicates that for most sub-watersheds more than one single management solution can be recommended on the basis of the different perspectives. The results showed that the multiple-criteria decision making serves as a valuable tool to represent the watershed system as a whole, to incorporate output from models and expert-judgments to examine the trade-offs among outcomes necessary to decision making and to communicate uncertainty of the parameters.