1979~2010年和墨洛绿洲区地下水时空演变与归因

THE SPATIO-TEMPORAL EVOLUTION OF THE GROUNDWATER SYSTEM IN RELATION TO CLIMATE CHANGE AND HUMAN ACTIVITIES IN HE-MO-LUO OASIS FROM 1979 TO 2010

地下水系统的演变机制对干旱区地下水资源的可持续管理至关重要。基于地下水观测数据、水文地质资料、气象资料和灌溉用水的统计数据，运用Mann-Kendall趋势检验、地质统计学和地下水储量计算法，研究了和田河流域1979~2010年地下水埋深和储量的时空变化，并应用灰色关联法分析了地下水时空演变的影响因素。结果表明：1979~2010年和墨洛绿洲地下水埋深呈增大趋势，枯水季增大趋势略大于丰水季。30年间地下水储量减小的平均速率为2567×104m3/a，尤其是2004年以后地下水储量锐减，2004~2010年地下水储量的平均减小速率是1979~2004年的8.16倍。从空间分布上，地下水埋深增加有从冲洪积扇缘向扇顶递减的趋势。地下水埋深增大、地下水储量递减主要是由于灌溉面积增加导致地下水开采增加引起的，人类活动对地下水均衡变化的作用大于自然要素的影响。可持续的绿洲农业水资源管理，是维持绿洲地下水安全的关键。

The impact of climate change and human activities on the evolution of groundwater systems is critical to the sustainable management of water resources in arid inland river basins. The Hotan River Basin is located in the west of the Taklimakan Desert and seated in the northern foothills of the Kunlun Mountains. The development of agriculture and animal husbandry increased the demand of groundwater resource, directly affecting the stability of He-Mo-Luo oasis and evolution of groundwater system. Based on groundwater observation data, hydrogeological data, meteorological data and irrigation statistical data, we use Mann-Kendall method, geostatistical analyses for the trends and the spatial distributions of the groundwater levels during the period of 1979~2010 in He-Mo-Luo oasis（36°50＇~37°40＇N, 79°20＇~80°40＇E）. The change of groundwater storage was estimated. The gray correlation analysis was conducted to study the extent of correlation between natural and human factors and the spatio-temporal evolution of groundwater. The results showed that：（1）The groundwater level has generally fallen from 1979~2010, with the downward trend slightly larger in dry season than that in wet season. The largest groundwater depth appeared in June and July. （2）Comparison of 1979,1999,2004 and 2010 maps revealed a spatial distribution of groundwater level decline. The groundwater level falls down from the downstream discharge areas to the recharge areas of the Hotan River alluvial fan. Where as a regular decline was seen in more than 60% of the area, the range of levels were declined from 1~3 m to 3~6 m. （3）The groundwater storage dropped by an average of 2567×104 cubic meters per year in the past 30 years, especially decreasing sharply after 2004. The reduction rate of groundwater storage in 2004~2010 is 8.16 times that of 1979~2004 years. （4）During the last 30 years, farmland area increased by 1261.93 km2 in He-Mo-Luo oasis, the amount of irrigation water was increased by 19.21%, and the groundwater exploitation has increased by 7.2 times. The natural and human factors affecting the change of groundwater storage arrangement by their decreasing importance are：Groundwater exploitation, irrigation area, precipitation, evaporation, runoff, temperature, irrigation leakage. Excessive groundwater depletion in major part of the district may be attributed to indiscriminate abstraction and increase in irrigation area. The effect of human activities on the groundwater balance is greater than that of natural factors. The sustainable management of the water and land resource is the key to maintaining groundwater security in oases.