Abstract: The ecological integrity of a landscape is often threatened by economic developments.The balance between economy and ecology can be achieved through a landscape approach.A landscape approach is to create an ecologically sound landscape with possibilities for the development of conflicting types of land use.This involves the reallocation of land-use types in a way that adverse impacts are balanced out.The reallocation of land-use types should correspond to the potentials of the natural physical structures.A landscape approach considers the spatial interactions among adjacent managed or unmanaged ecosystems and how those interactions affect water resources and landscape ecology.For modeling and assessing both water resources and landscape ecology,success lies in our ability to perform watershed simulation with a system that integrates GIS with other spatial models.An integrated analysis of the coupling relationship between water systems and land uses can effectively assess ecological sustainability.An integrated analysis of the coupling relationship between surface water and groundwater systems can effectively evaluate aquifer vulnerability.Without an understanding of watershed hydrology,it is impossible to comprehend the temporal and spatial variations in water resource and landscape ecology.It is recognized that optimal spatial arrangement of conflicting land uses may actually reduce the flood threats and minimize the water quality problems without jeopardizing the economic development.Thus,it is our goal to model these hydrological issues and associated landscape ecological problems by integrating GIS with other spatial models so that optimal spatial solutions can be found for the coupling watershed:Mahan Mountain/Xinlun Mountains and Lanzhou/Yuzhong Basins.

Key words: semiarid area, landscape ecology, GIS, modeling