关中平原渠井双灌区地下水循环对环境变化的响应  

Response of groundwater cycle to environmental changes in Guanzhong Plain irrigation district

作　　者：李萍[1] 魏晓妹[1] 降亚楠[1] 冯东溥[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,杨凌712100

出　　处：《农业工程学报》2014年第18期123-131,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：水利部公益性行业科研专项(201301016);陕西省水利科技计划项目资助(2011-07);国家科技支撑计划项目(2012BAD08B01)

摘　　要：为促进陕西关中平原渠井双灌区地下水良性循环,保障灌区水资源高效安全利用,以泾惠渠灌区为例,分析了灌区多年来地下水系统外部环境因素及地下水循环要素的变化特征,基于多变量时间序列CAR(controlled auto-regressive)模型建立了地下水位动态对环境变化的响应模型,利用验证后的模型对灌区不同环境变化情景下的地下水位埋深进行了模拟。研究结果表明:降水、蒸发、渠首引水、渠井用水比例是影响灌区地下水循环的主要外部环境因素;降水量减少、蒸发量增加,地下水各项补给量减少、排泄量增加,使得地下水位逐年下降,近34 a累计下降11.8 m;在多年平均降水量情景Ⅰ下(近56 a均值:513 mm),维持灌区地下水良性循环的适宜渠井用水比例为1.53,在多年平均降水量减少5%,即降水情景Ⅱ下(487 mm),适宜渠井用水比例为1.61。环境变化下不同渠井用水方案的研究,有利于灌区地下水的良性循环,可为灌区制定高效安全用水对策提供依据。Healthy groundwater cycle can ensure that water resources are used more efficiently and securely in northern irrigation district. In recent years, groundwater cycle condition in the irrigation district affected by climate change and human activities has changed greatly. Environmental problems such as the attenuation of groundwater storage capacity, hanging pump wells and the groundwater deterioration occur with the unhealthy groundwater cycle in some northern areas, which directly affect the safety and efficiency of water resource utilization in the irrigation district. Therefore, studies on response of groundwater cycle to environmental changes in the irrigation district are urgent and important. This study took Jinghui Canal Irrigation District in Shaanxi province as a research area, analyzed variations of characteristics of external environment factors for groundwater system and groundwater cycle elements over the years by trend analysis and spearman rank correlation test. A forecasting model of groundwater depth affected by external environment was established based on multivariate time series CAR model （Controlled Auto-regressive）. Groundwater depth under different environmental scenarios were predicted using validated models. The prediction problem of complex nonlinear time series can be effectively solved by using CAR model. In order to evaluate the prediction effects of CAR model, its results were compared with those from other models including support vector machine （SVM） prediction model and radial basis function （RBF） network model. The results showed that the prediction effect of CAR model was much better than SVM model and RBF network model. The specific research results of this paper showed that the main external environment factors affecting groundwater cycle were precipitation, evaporation, irrigation intake water from canal head, and irrigation water ratio of channel and well. Precipitation was in a significantly decreasing trend while evaporation was in a unnotable increasing trend f

关 键 词：灌溉 模型 水分管理 地下水循环 泾惠渠灌区 多变量分析 CAR(Controlled Auto-regressive)模型 

分 类 号：S271[农业科学—农业水土工程]