Modelling the response of surface water quality to the urbanization in Xi'an, China.

The study investigated the response of surface water quality to urbanization in Xi'an, China. We qualitatively described the change in urban land use from 1996 to 2003, analyzed the status of the surface water environment, and constructed a model of urban expansion to simulate the water environment's response to urbanization. Our results revealed that patterns of land use changed dramatically, the rate of economic growth exceeded that of urbanization during the study period, and increasing urban land use was correlated with fluctuations in water quality. The simulated results suggested that urbanization had reached the environmental carrying capacity based on the average land utility and the marginal costs of pollution.