The Role and Importance of the River Ecosystem Functions UsingMulti Criteria Decision Making Models(Case Study: Tajan River in Sari City)

Urban rivers as one of the natural structures of the city are important cities sources because of their environmental, economic and cultural values and the provision of ecosystem services. The purpose of this study investigate the role and importance of Tajan River ecosystem functions as one of the most important rivers of Iran in Mazandaran province, Sari. In order to achieve this purpose, multi-criteria decision models includes Entropy to calculate functions weight of the river ecosystem and Technique Order of Preference by Similarity to Ideal Solution (TOPSIS) and the Simple additive weighting (SAW) to prioritize functions. In this study, research data were extracted from field survey, random sampling and from 239 questionnaires completed by Sari citizens in winter 1397 and spring 1398 to show which of the ecosystem functions of the Tajan River, including regulatory, habitat, productivity and information functions, is importance for Sari citizens. Analysis of weighting Tajan River ecosystem functions in Sari with Entropy technique showed that habitat, productivity, information and regulatory functions gained 0.2511, 0.2501, 0.2500 and 0.2488 weights, respectively. According to the results of the prioritization Tajan River ecosystem functions with TOPSIS and SAW models, habitat, productivity, regulatory and information functions take the first to fourth priority respectively.  Also, the results showed that habitat function for 39% of the citizens, productivity function 27% of the citizen, regulatory function 25% of citizen, information function 9% of the citizen had priority. By identifying and determination the priority of Tajan River ecosystem functions, it is suggested that the results of the present study used as a model for designers and decision makers of river engineering and improvement of urban river landscape, and projects be done for the balance of the river ecosystem and the sustainability of the quality of the urban environment.