平罗县不同地下水位分布区地下水埋深变化特征分析

【目的】明确平罗县不同水位分布区的地下水埋深变化特征,更好地指导合理用水和防治土壤盐渍化。【方法】选取2007-2017年平罗县不同地下水位分布区内9眼地下水位观测井的月观测数据以及引黄水量、地下水取水量、水稻种植面积、降雨量和年平均气温等数据,分析了平罗县不同地下水位分布区地下水埋深变化特征及其影响因素。【结果】平罗县地下水埋深年内变化幅度大于年际,随月份呈"W"形变化,随年份呈平缓波浪形变化,5-8月和11月-次年1月,各观测点地下水埋深变化曲线呈聚集状态,其他月份则呈离散状态;不同地下水位分布区地下水埋深年际间变异系数表现为:高地下水位>中地下水位>低地下水位,年内无明显规律。与中、低水位分布区相比,高水位分布区地下水埋深不稳定;从各观测点年均地下水埋深与降雨量、平均气温、水稻种植面积、引黄水量和地下水取水量相关性来看,平罗县高、中水位分布区地下水埋深变化更多地受引黄水量影响,水稻种植面积的增加对降低高水位分布区地下水埋深起到了积极作用。【结论】建议平罗县高、中水位盐碱地的改良应减少引黄水量、利用浅层地下水或农田退水灌溉以降低地下水位。

Spatiotemporal Variation in Groundwater Table in Pingluo County

【Background】Rising and falling of groundwater table is closely related to soil salinity in arid and semi-arid region and understanding the characteristics of seasonal groundwater fluctuation is critical to improving water and salt management.【Objective】The purpose of this paper is to analyze the spatiotemporal variation in depth of groundwater table in Pingluo County in Ningxia of China in attempts to improve its irrigation water use efficiency while in the meantime mitigating soil salinization.【Method】This study selected the monthly data of nine groundwater observation wells located in the area with different groundwater depth from 2007 to 2017,and the data of five influencing factors including water diversion from Yellow River,groundwater withdrawal amount,rice planting area,rainfall amount,and annual average temperature.The spatiotemporal variation in groundwater table and its leading factors were analyzed by the mathematical statistics method【Result】Intra-annual variation in the groundwater table was greater than inter-annual variation in the studied area.The monthly average groundwater table changed in"W"shape from spring to winder.From May to August and November to January of the following year,the groundwater change curves of all nine boreholes showed a drop,while in other months it rebounded.The variation coefficient of interannual groundwater table change in areas with different groundwater depth was ranked in:deep groundwater level>moderate groundwater level>shallow groundwater level,and this trend remained almost unchanged in the ten years.Compared with areas with moderate and shallow groundwater table,deep groundwater table was unstable.Correlation analysis revealed that water taken from the Yellow River and groundwater extraction were the two factors that affected the shallow and moderate groundwater most in the areas adjacent the Huinong Canal that diverting water from the Yellow River.The increase in cropping land also had a positive impact on groundwater table dropping.【Conclusion】Mitigating existing and potential soil salinity in the areas with shallow groundwater table should consider reducing the amount of water taken from the Yellow River for irrigation,using shallow groundwater or farmland drainage irrigation to ruduce groundwater table.