Fuzzy ranking the effects of subsurface water level rising in un-sewer network cities on the underground water structures (Case study: Kerman city)

The rising of subsurface groundwater level has different multiple damages on the water and wastewater infrastructures in the Kerman city. In the current study to infer the damage effects of rising water level on the underground water structures (urban water distribution networks, sewer collection network, water transfer lines and underground pumping stations) firstly the water level changes are studied, then the FAHP is used to infer and ranking the destructive effects. based on the results of fuzzy ranking, healthy and environmental destructive effects with 0.34 relative weight are the most important one. The operational and performance damages with 0.27 relative weight, the structural and physical damages with 0.15 relative weights are ranked. In the physical class of damages, the corrosive damage of pipes and concretes with 0.25 relative weight has the highest level of risk. In the physical class of damages, the reduction in reliability and insurance has 0.26 relative weight followed by reduction of hydraulic power, sedimentation and entering the roots with 0.2 relative weight, and changes in water and wastewater quality and quantity have the relative weight 0.23. Also, the leakage of the pollutants from and into the water-wastewater networks have the relative weight 0.26 in the class of health and environmental damages. Finally, in the class of economical and cost damages the risk of increasing in the operation and maintenance of the networks with 0.31 relative weights identified as the most important destructive damage.