1985-2013年黑河中游流域地下水位动态变化特征

在气候变化和人类活动的影响下, 黑河流域地表水和地下水的时空分布特征发生了很大变化. 研究水系统演化及其驱动机制对流域水资源可持续管理非常关键. 基于甘肃河西黑河中游流域地下水位动态、水文气象、土地利用和灌溉统计数据, 研究了1985-2013年黑河中游流域地下水位时空变化. 结果表明: 地表水的不合理分配和耕地的扩展导致了地下水的过量开采和地下水位的剧烈变化. 1985-2004年区域地下水位以下降为主; 2005-2013年呈现下降和回升两极发展趋势, 冲洪积扇群带地下水最大下降达17.41 m, 而黑河干流沿岸地下水位最大回升了3.3 m, 地下水埋深普遍增加了1.0~3.0 m. 尽管地下水位在2005-2013年表现出回升趋势, 但干流中游盆地地下水系统处于严重负均衡状态, 制定合理的“生态分水”方案和水资源综合管理规划非常紧迫.

Dynamic variation of the groundwater level in the middle reaches of the Heihe River during 1985-2013

Temporal and spatial distribution and characteristics of surface water and groundwater have greatly changed under the impacts of climate change and human activities in the middle reaches of the Heihe River. Study the evolution of water system and the mechanisms driving the change are critical for sustainable water management of the river basins. Based on groundwater levels of the monitoring wells and hydrogeological data, meteorological data, remote-sensing data and statistical irrigation data, variation of groundwater level caused by surface water allocation was studied in the middle reaches of the Heihe River in the past 30 years. Results show that the unbalanced allocation of surface water and cropland expansion have resulted in the over-abstraction of groundwater and then lowered the groundwater table and renewable quantity. Groundwater level had declined in 1985-2004, and had declined and risen again during 2005-2013. The lowering groundwater level had reached a maximum of 17.41 m in the upper and middle alluvial-diluvial fans, with a maximum rising (3.3 m) along the main Heihe River, during 1985-2013. Generally, groundwater table had risen 1.0-3.0 m. Groundwater system had fallen in severe negative balance, although the groundwater level had presented a rising tendency during 2005-2013 in Zhangye basin. It is urgent to make a rational policy of “eco-water diversion” and integration planning and management of surface water and groundwater resources in the river basin.