RESUMO
The expansion of major cities regardless of the scientific planning principles has led to the emergence of negative urban development impacts in Iran such as the degradation of natural resources and various forms of pollution. Undoubtedly, urban rivers can enhance the ecological value of the earth to an optimal extent. However, to benefit from these potentials, appropriate planning looks inevitable. Due to the lack of data and information, analyzing the quality of these resources requires the application of new methods which consider the uncertainties and complexities of the issue in the decision making. This research presents an application of fuzzy TOPSIS multi attribute group decision making to identify factors causing land degradation, distinguish the most optimal areas based on their ecological values and provide suggestions on landscape improvement. To this end, the development of Shiraz city along the Khoshk River corridor was investigated using the 1:25000 maps and satellite images [ICONOS]. With respect to the river attributes and adjacent lands, the riverside was divided into four heterogeneous zones. Then, to distinguish the most optimal zone based on the ecological values, the fuzzy decision making method was applied. To this end, the expansion of human activities and biophysical criteria were defined, separately. A number of experts determined the importance of each indicator qualitatively. Finally, using the group decision making theory and fuzzy TOPSIS technique, the researchers identified the most suitable zone based on the [biophysical criteria] and [human activity criteri] separately as well as the whole criteria, and provided suggestions on the landscape improvement
RESUMO
Multicriteria decision analysis tool is used in many water resources and environmental management projects. The Malnichara is one of the natural channels in Sylhet city [Bangladesh] responsible for storm runoff conveyance to the downstream Surma river. The channel is found to be encroached at many locations of the city and found to be very vulnerable. The authority has taken decision to improve natural channels by a traditional approach, e.g. constructing box culvert. In most cases, stakeholders' participation is ignored in such type of decision making. Hence, efforts were made to evaluate three common alternatives viz. sodding natural channel, lined natural channel and box culvert for the channel improvement. The channel is hydrologically divided into two parts: the upper portion [Choukidekhi-Kanishail] and the lower portion [Kanishail-Topoban]. Both parts were separately analyzed. Small groups of stakeholders were interviewed for the selection of criteria and for the assignment of weighed factor and scores. Experts' opinions were also taken through consultation. Nine criteria from four categories such as technical, economic, environment and social aspects were selected. The relative performances of alternatives were evaluated using the weighed sum technique of multicriteria decision analysis. It was found that the sodding natural channel is the best alternative for both portions of the channel. However, the choice is very sensitive to the social criteria