The Change Of Water Resources In HeiHe River Basin And Its Influence Of LUCC

Water is an essential material to the survival of human and all biological, as human beings a necessary and irreplaceable resources, is an important material foundation to achieve sustainable socio-economic development. Heihe River Basin is located in the northwest arid area, water scarcity, especially in downstream, serious land degradation. Therefore, the research on the changes and trends of water resources in the Heihe River Basin, is important to the regional economic, social, and ecological and environmental sustainability.This paper, based on the statistical data since 1980, analysis the trends of precipitation, surface water and groundwater resources in Heihe River Basins by the method to trend analysis ,and combining the two land-use data , analysis water resources change to the impacts of the land use change, the following conclusions:(1) In 1980～2008, the distribution of spatial and temporal precipitation in Heihe River Basin is uneven, during the year the rainfall is concentrated in May-September; Upper, middle and lower reaches of precipitation are significantly different. In 1980～2004, the annual average runoff of Qilian station and Yingluoxia station showed an increasing trend, a decreasing trend in Zhengyixia station , Gaoya station and Zamashike station had no significant changes. However, the runoff of the "wet - dry" season changes in each station are different, the different distribution of precipitation of the upper, middle and lower reaches is the main reason for this difference. In 1978～2004, groundwater level of Heihe River Basin has the trend of deepened in the groundwater wells, except for Luocheng well in Gaotai county, which shows a decreasing trend of groundwater .(2) Climatic factors and human activity factors were the main reasons for water resources changes. Study on moisture and runoff correlation analysis nearly three decades, showed that climate change and water resources in Heihe River Basin was weakly correlated. So climate change is the main factor causing changes in water resources various in Heihe upstream.The human activity is the main factor to influence the middle and downstream water resources change. Human activity factors impact on changes on water resources mainly for the aspects of water supply, water using and water consumption. According to data obtained in Gansu Province Bulletin of water resources in 2005, surface water is the main source of the Heihe River Basin water supply, groundwater supply is one in seven of the total water supply. Water for agricultural irrigation accounts for the largest share of water, the next is forestry, animal husbandry, livestock and fisheries, the Heihe River Basin water use is still the traditional irrigation water.On the other hand, the huge consumption of agricultural irrigation water shows that rational development and utilization of water resources, improve water efficiency, are also the focus problem of Heihe River Basin.(3) Spatial distribution of water resources in Heihe River Basin affects land-use patterns, and water changes are also contributed to the reasons for the land-use conversion. Recent years, mainly because of the lack of the rainoff and the decrease of the groundwater level, the Heihe river basin has experienced the land salinization and the increase of the sands area.