environmental impacts of urban utility tunnel construction (case study: urban utility tunnel district 22 of tehran)

urban facilities are necessary components of cities. in all grown and developed cities of the world there are tremendous network of facilities such as water and electric ties, water sewage drainage, water piping and gas piping. that has not been installed in proper depth underground and locations and with growing of the cities and consumption of population. they need to be replaced by excavating the pavement on the streets which creates practically traffic difficulties and some environmental problems. current system of urban facilities distribution in tehran have a lot of loses, the main cause of this, is creating branch without the necessary calculations and obsolescence of networks. use of utility tunnels started from few decades ago in most european (france, uk, and switzerland) and american countries. inside the country accomplished some works about utility tunnels construction from few years ago for example urban utility tunnel construction in district 22 of tehran. in this research the environmental conditions of investigated area (physicochemical, biological, social- economic) and field studies related to the tunnel constructions, measurement of sound and air pollutants in 6 monitoring station in construction and operation phase have been done. then by using integrated matrix (leopold - saratoga) impacts of the utility tunnel constructions on the environmental parameters were studied. the findings indicated that utility tunnel construction have positive effects on social and economic environment such as job creation and improved( welfare facilities, urban transportation systems, quality of life and landscape), but also have some negative effects on physicochemical environment such as noise, and air pollutions .that negative effects can be decrease by applying proper management.