Location of Risk Zones in Water Network Systems Quality Crisis With GIS, AHP Approach Case Study: Water Network Of Tehran

Urban water distribution network is subject to quantitative and qualitative threats. Quality threats include chemical and biological threats. The crisis in quality of urban water network directly affects human life in three areas of residence, work and activity, and can turn a technological crisis into a social and political one. The first step in the passive defense engineering strategy of urban water supply network is identification of areas at risk; distinguishing places with high risk profiles and selecting appropriate locations for installing water quality controllers. This study spans these five general criteria: damages to pipes, valves, breakers, directors; damages to tanks and water reservoir locations; people living and settled in the local housing facilities; people active at the local workplace, commutating citizens and traffic. It consists of 17 sub-criteria such as levels of service of areas and reservoirs, the distance from water transmission and distribution lines, proximity to contact tanks, refineries, tank floors, pumping stations and air tanks, population distribution and density, sensitive applications, regional work and activities and municipal services, green space, proximity to subway, highway network, railway network, and a network of ways, metro stations and metro lines. The AHP binary method of comparison carried out by 30 researchers using GIS spatial analysis with combination of sub criteria Tehran zone is divided into five categories: super critical, critical, short-term priority, medium term priority and without priority. Finally, as well as analyzing Tehran completely, three zones are shown to be most risky.