气候变化和人类活动对灌区地下水埋深的影响

【目的】探析气候变化和人类活动对灌区地下水埋深的影响。【方法】利用年代波动性分析、突变检验、灰色关联分析、敏感性分析、双累积曲线法和相对贡献率分析了人民胜利渠灌区1952—2013年地下水埋深及其影响因素的变化和突变特征,并识别了地下水埋深与各影响因素间的响应特征。【结果】人民胜利渠灌区地下水埋深呈明显增加趋势(0.8 m/10 a)。地下水埋深在1952—1959年的变异系数最大,为27.33%,呈中等变异性;降水量、蒸发量、平均气温和灌溉水量在1960s的变异系数最大,其中蒸发量和平均气温呈弱变异性。地下水埋深、降水量、蒸发量、平均气温和灌溉水量的突变年份分别发生在1984年、1970s、1972年前后、1973年前后以及1993—1996年。各影响因素对地下水埋深的影响程度大小为平均气温>降水量>灌溉水量>蒸发量,敏感程度为平均气温>蒸发量>降水量>灌溉水量。各影响因素对地下水埋深的贡献大小呈平均气温>蒸发量>灌溉水量>降水量,其中平均气温的贡献率最大为38.16%,降水量的贡献率最小为17.40%;2002—2013年灌溉水量对地下水埋深的贡献率最大为47.05%。【结论】不同时间阶段各影响因素对地下水埋深的贡献不同,1952—1963年蒸发量的贡献最大,1964—2001年平均气温的贡献最大,2002—2013年灌溉水量的贡献最大。

The Effects of Climate Change and Anthropogenic Activities on Groundwater in Irrigation District

【Background and objective】Groundwater is the most important water resource for agricultural production in many regions around the world and its spatiotemporal changes are affected by a multitude of natural and anthropogenic factors.Understanding their quantitative relationship is hence imperative not only to sustain agricultural production but also to safeguard the development of other sectors.Taking an irrigation district in central China as an example,this paper analyzed the fluctuation of its groundwater depth in response to climate change and anthropogenic activity.【Method】The analysis was based on groundwater and meteorological data measured from 1952-2013 from the People’s Victory Canal Irrigation District.Their changes and relationship were analyzed using the decadal volatility analysis,mutation test analysis,gray correlation analysis,sensitivity analysis,double cumulative curve method,and the relative contribution rate method.【Result】The groundwater depth in the district has been increasing at an average rate of 0.8 m/10 a.The maximum coefficient of variation of the groundwater depth from 1952—1959 was 27.33%;the coefficients of variation of the precipitation,evaporation,average temperature and the amount of irrigation water all peaked in 1960 s,though the variation of the evaporation and average temperature was not as strong as other factors.Abrupt changes in groundwater depth,precipitation,evaporation,average temperature and irrigation water amount occurred in 1984,1970 s,1972,1973 and 1993—1996,respectively.The influence of each factor on groundwater depth was ranked in the order of average temperature > precipitation >irrigation water amount > evaporation,while the sensitivity of groundwater depth to different factors was ranked in the order of average temperature > evaporation > precipitation > the amount of irrigation water.On average,the contributions of the different factors to groundwater depth change were ranked in the order of average temperature >evaporation > irrigation water amount > precipitation.The average temperature contributed most to the groundwater depth change accounting for 38.16%,and the least was precipitation contributing 17.40%.Irrigation water affected groundwater depth mostly from 2002 to 2013,contributing 47.05% of the change.【Conclusion】The factors affecting the groundwater depth in the district varied with time,with evaporation being dominant from 1952 to 1963,average temperature from 1964 to 2001,and irrigation from 2002 to 2013.