近20a来黑河中游张掖盆地地下水动态变化

Variations of Groundwater in Zhangye Basin of the Middle Reaches of the Heihe River in Recent Two Decades

在研究黑河中游张掖盆地水文地质条件及对区内地下水进行动态分区的基础上, 总结了区内1981-2001年地下水水位、储量的时空变化规律. 结果表明: 1)盆地内部沿冲洪积扇自上而下的 4 个区域内由于赋存条件的差异, 地下水多年动态类型分异显著. 其中, 冲洪积扇中上部 20 世纪 80 年代的10 a内地下水储量累积减少56.47×106m3, 90年代地下水储量累积减少150.83×106m3; 冲洪积扇下部80年代储量减少11.80×106m3, 90年代减少77.50×106m3; 细土平原 2 0 a 内储量累积减少0.56×106m3; 临高河谷平原近20 a内储量增加了 1.78×106m3; 进入 90 年代后, 各区域变化幅度均有不同程度增加. 2)各区域内地下水年内动态类型复杂, 存在显著的季节差异, 在进入 90 年代后年内动态变化也均有不同程度的增强.

To study the variation of groundwater, which is an important source and the best choice for drinking water in the arid regions, is vital to the sustainable exploitation, utilization, and reasonable management of groundwater. Based on the investigation of hydrogeological conditions in Zhangye Basin in the middle reaches of the Heihe River and the division of groundwater, the temporal-spatial variations of groundwater level and storage from 1981 to 2001 are analyzed. It is revealed that: (1) Due to the difference of the storage conditions, the annual variation of groundwater is differential remarkably in the four sub-areas. In the upper-middle of the alluvial-diluvial fan, the storage of groundwater totally reduced 56.47×10~6m^3 in the 1980s, and 150.83×10~6m^3 in the 1990s; in the lower part of the alluvial-diluvial fan, it reduced 11.80×10~6m^3 in the 1980s, and 77.50×10~6m^3 in the 1990s; in the fine-grained soil plain, it reduced 0.56×10~6m^3 in the two decades; and in the river-valley plain, it totally increased 1.78×10~6m^3 in the two decades. Furthermore, the variation range increased individually in the 1990s. (2) The monthly variation of groundwater of every area in the basin was complicated, and had the remarkable temporal differential. Exploited and hydrological-runoff variations were primary in the upper-middle of the alluvial-diluvial fan; there were hydrological-runoff and irrigated variations in the lower part of the alluvial-diluvial fan; the irrigated-exploited and the irrigated-runoff types were dominant in the fine-grained soil plain; and in the river valley plain the irrigated-runoff was the primary variation type. Moreover, the monthly variation seemed to be enhanced to some extent in the 1990s.