Abstract: Based on analyses on the problems in the water and land resources exploitation in previous period, the paper puts forth the basic thoughts on land and water resources exploiting after implementing the policy of returning farmland to forest and grassland in arid area of Northwest China. With the principle of water balance, a quantitative models on the main line of impacts of land use and vegetation variation to groundwater is set up, and the forecast on land and water resources variation is given under the present model of land and water resources developing. With definite conceptions, the model has simple form and applies easily-acquired data. Taking the Minqin Oasis of Gansu Province as an example, the mode of land and water resources exploiting with the core aim of realizing the minimum utilization contradictions between land and water resources in the oasis and giving both considerations to eco-environmental benefit and socio-economical benefit is presented based on taking the influence of land use as source and concentrating item to process and the analyzed results of the impact of land utilizing mode to temporal and spatial variation of groundwater. Taking the Sangonghe River Basin of Xinjiang as another example, the mode of land and water resources exploiting with the core aim of controlling vertical water consumption within oasis and groundwater exploitation rationally and giving both considerations to eco-environmental benefit and socio-economical benefit is presented based on taking the influence of vegetation variation as source and concentrating item to process and the analyzed results of the impact of vegetation variation to temporal and spatial variation of groundwater. According to the case studies, the paper presents a theoretical way used to solve the long-term disputes on how to exploit surface water and ground water rationally between the water conservancy department and hydrogeological department and confirms that the modes of land and water resources exploiting are rational in economic effects and favorable in ecological effects.

Key words: arid area, land and water resources, land use, Northwestern China