Xi'an, one of the biggest cities in the middle part of china, is along the Weihe River which is a branch of the Yellow River. In resent years, its water demand has been increasing drastically due to rapid industrial development and population growth. Infrastructure, such as water supply and wastewater treatment plants, however has not established enough yet, so serious water problems in quality and quantity have appeared. For example, ground subsidence has occurred by too much ground water abstraction, and water pollution has been more seriously by increasing domestic, industrial and agricultural wastewater disposal. So constructing an efficient water utilization system is an urgent need in this region. In this study, the authors investigate water balance and pollutant load fluxes in Xi'an City based on field surveys, and by analyzing GIS data and using SD. In conclusion, in Xi'an City, ground water accounts for 70% of the total water use and its amount decreased 0.9 billion tons from 1993 to 2001. The total BOD amount into the rivers is about 0.2 million tons in 2001 and its 90% is from domestic and industrial waste waters.
