关键词: 干旱区, 半干旱区, 水资源, 持续开发利用, 对比分析

Abstract: Water resources are critical to the development of regional economy and to the protection of ecosystem and environment, especially in the arid and semi arid regions. Along with the increase of population, the development of industry and agriculture, and the deterioration of water quality in the arid and semi arid regions of Gansu Province, the sustainable utilization and exploitation of water resources are crucial. This paper is intended to make a comparative study of the composition of water resources, the problems in the exploitation and utilization of water resources, and the management and the policy supporting system of water resources in the arid and semi-arid regions of Gansu Province. The semi arid regions are mainly distributed in the middle and east of Gansu Province, while the arid regions are located in the Hexi Corridor in front of mountains. In the semi arid regions, precipitation is the source of water resources; therefore rainwater collecting engineering of irrigation is the main way of the water resources utilization. In the arid regions, the runoff from mountainous watersheds is the source of water resources. Precipitation and melt water from glaciers and snow cover form runoff in mountains. Therefore, the oasis agriculture in front of mountains is irrigated by the runoff from mountains, and the water saving irrigation is the main way to rise the efficiency of water resources utilization. Annual runoff variation is larger in the semi arid regions, while that is rather smaller in the arid regions. Both the arid regions and the semi arid regions are lack of water resources, but it is much more serious in the semi arid regions. The arid and semi arid regions are facing the problems of increasingly serious contamination of water and rising of mineralization of the ground water. In the semi arid regions, the emphasis of the water resources management should be put on artificial interception of atmosphere precipitation, rational exploitation of ground water and planning of surface water utilization. For interception of precipitation, great progress has been achieved in the last 30 years. Nevertheless, there is still a lack of scientific allocation and management of water resources. From a long term of view, water laws and policy should be gradually perfected, and the sewage treatment and irrigation system should be set up. In the arid regions, the water saving economy should be achieved by the spreading of water saving technology. In Hexi Corridor, a large proportion of water resources are consumed by agriculture, hence the agriculture water saving technology is critical. The management of drainage basins is also very important. It is necessary not only to coordinate the rational allocation of water resources for the oases at the upper and lower courses of the inland river basins, but also to coordinate the water resources utilization of the ground water and surface water, the clean water and sewage water. The protection of the mountainous water resources and the water utilization in oasis agriculture and ecosystem protection in the down course area should be balanced in the inland river basins, in order to achieve the sustainable exploitation and utilization of water resources.

Key words: arid and semi arid regions, water resources, sustainable exploitation and utilization, comparative analysis