Restoration and Reclamation of the River Valleys’ Landscape Structure for Urban Sustainability using FAHP Process, the Case of Northern Tehran- Iran

Tehran city has been subject of critical environmental challenges during the course of 20th century namely: massive population growth, broad expansion, reduction in urban open/green spaces, increasing in energy consumption and waste production. Releasing industrial wastewater into river valleys have led to considerable changes in structure of city’s natural landscape. The natural structures of river valleys in northern Tehran that historically function as ecological corridors for transferring surrounding air and water into city, helping urban sustainability, have been gradually turned into large concrete canals for urban wastewater to downstream land, damaging ecosystems balances and biodiversity needs. The eradication of green spaces on the river banks accelerated the rivers environmental degradations. This research aimed at examining the structure of northern Tehran landscape and the influential factors which play role in the river valleys‘ landscape destruction. The contributing parameters to restoration of these ecological corridors were investigated based on a tree structure. Using FAHP-Fuzzy Analytical Hierarchy Process- the questionnaires distributed among experts, and factors were classified. Then Chang’s methodology employed and finally ranked by degree of importance. Outcomes of FAHP were used as input for Arc GIS 9.3 to export the analytical maps of Tehran‘s urban landscape enhancement through river valleys’ restoration. Evidence from this research show that alteration in environmental structures(vegetation cover, micro climate, urban infrastructures, hydrology) comes with greatest importance in shaping existing changes. Restoration of river valleys’ structures are therefore, possible through improving their natural functions i.e. biological structures, urban green patches and enhancing network connectivity among patches.