ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    旱区土地利用变化对地下水动力场和化学场的影响:以新疆孔雀河流域为例

    Impact of Land Use Change on Groundwater Regime and Hydrogeochemistry: A Case Study in the Kongqi River Catchment of Xinjiang

    • 摘要: 旱区土地利用变化对地下水动力场和化学场的影响是国内外的研究热点问题。笔者以新疆孔雀河流域为研究区,分析了土地利用变化条件下地下水动力场和水化学场的时空演化规律。研究表明:近50年间,孔雀河流域耕地面积急剧增加,地下水开采量不断增大,同时地表水大量被引走用于灌溉,使得河道入渗补给地下水量减少,共同导致孔雀河流域地下水位明显下降,下降幅度普遍在10~40 m,局部地区下降达50 m以上,并形成地下水降落漏斗,孔雀河中下游河流与地下水补排关系也由原先的地下水补给河流转变为河流渗漏补给地下水。土地利用变化通过影响地下水循环条件和水文地球化学作用,造成水化学场发生变异。地下水位下降,潜水蒸发浓缩作用减弱,同时低矿化度河水灌溉使得淋滤作用增强,造成研究区地下水TDS总体降低。地表水灌溉还使得漏斗区水化学混合作用增强,造成地下水化学类型由Cl·SO4型转变为HCO3·Cl和HCO3·Cl·SO4型。本研究可为孔雀河流域和类似地区地下水合理开发利用与保护提供科学依据。

       

      Abstract: The impact of land use change on groundwater regime and hydrogeochemistry is one of the hottest research topics in the hydrogeological community. This study took the Kongqi river Catchment of Xinjiang as the research area, the spatial and temporal distributions of groundwater regime and hydrogeochemistry were analyzed under the condition of land use change. The results indicated that over the last 50 years, The cultivated land increased rapidly, resulting in a continuous increasement in the amount of groundwater extraction. Additionally, a large amount of surface water was diverted for irrigation, which reduced the amount of groundwater recharge through river channel infiltration in the Kongqi river Catchment. This leads to a significant drop in water table and the formation of groundwater depression zones. The majority of drawdown was 10~40 m, with the biggest value of over 50 m. In the middle and lower reaches of the Kongqi river, the relationship between river and groundwater also changed from gaining steam to loosing stream. Land use change caused variations in hydrogeochemical fields by influencing groundwater circulation conditions and hydrogeochemical processes. The overall decrease in groundwater TDS in the study area was observed, due to a weakened evapotranspiration following water table decline and an enhanced leaching effect by irrigation using low salinity river water. Surface water irrigation also enhanced water chemical mixing in the depression zones, and led to the chemical type changes from Cl·SO4 to HCO3·Cl and HCO3·Cl·SO4. This study can provide a scientific basis for the rational development, utilization and protection of groundwater in the Kongqi river Catchment and similar areas.

       

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