Using Improved TOPSIS and Best Worst Method in prioritizing management scenarios for the watershed management in arid and semi-arid environments

Watershed as a complex and dynamic system is considered to be a functional unit for planning and management strategies. It is important to take all technical, social, economic, physical, ecological and administrative aspects in the process of watersheds planning and management into account. Deciding in the watershed management is quite intricate due to existence of diverse agents and indices there. Therefore, this study focused on the socioeconomic, ecological and physical impacts of management scenarios targeting on water and soil resources management issues in the Hable-Rud River Basin, Tehran Province, Iran. Also provide the best scenario for watershed management to achieve integrated management of resources in the catchment using Improved Technique for Order of Preference by Similarity to Ideal Solution (Improved TOPSIS) approach and Best Worst Method (BWM). The study area covers an area of 3269 Km(2). In this study, according to managerial problems of the region, four management actions (rangeland exclusion, pitting, contour furrow and pile seeding) and 16 management scenarios were taken into consideration. Also, four standards of social (social acceptance), economic (benefit/cost), ecological (Weighted Average of Patch Size Index (WMPSI) and Weighted Land Cover Area Index (WLCAI)), and physical (runoff and soil erosion) indices are applied. Then, using the Best Worst Method, the weight of each index is met. Following the formation of decision matrix with 16 options (management scenarios) and 6 criteria (evaluation index), the Improved TOPSIS method was used to prioritize management scenarios. The research results showed that the social acceptance index (0.304) has the highest weight and the WLCAI index (0.072) has the lowest weight. The results of the prioritization of the scenarios using the weights estimated by the BWM method showed that the scenario 13 (rangeland exclusion, pitting and pile seeding) and scenario 5 (pile seeding) and scenario 16 (rangeland exclusion, pitting, contour furrow and pile seeding) perform best, respectively. In this research, a novel and logical approach of multi-criteria decision-making processes, i.e., Improved TOPSIS and Best Worst Method, was adopted to prioritize management scenarios for planning and watershed management. Given the results, the Improved TOPSIS method can be used as a suitable technique in prioritizing management scenarios, especially when the decision maker faces contradictory or even conflicting objectives and cannot decide on the best alternative(s).