CAJ | 학술논문

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。
위촉진협서관중평원거정쌍관구지하수량성순배，보장관구수자원고효안전이용，이경혜거관구위례，분석료관구다년래지하수계통외부배경인소급지하수순배요소적변화특정，기우다변량시간서렬CAR（controlled auto-regressive）모형건립료지하수위동태대배경변화적향응모형，이용험증후적모형대관구불동배경변화정경하적지하수위매심진행료모의。연구결과표명：강수、증발、거수인수、거정용수비례시영향관구지하수순배적주요외부배경인소；강수량감소、증발량증가，지하수각항보급량감소、배설량증가，사득지하수위축년하강，근34 a루계하강11.8 m；재다년평균강수량정경Ⅰ하（근56 a균치：513 mm），유지관구지하수량성순배적괄의거정용수비례위1.53，재다년평균강수량감소5%，즉강수정경Ⅱ하（487 mm），괄의거정용수비례위1.61。배경변화하불동거정용수방안적연구，유리우관구지하수적량성순배，가위관구제정고효안전용수대책제공의거。
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 from 1955 to 2010. The Hurst index of precipitation and evaporation were 0.69 and 0.56 respectively. The irrigation intake water from canal head, the surface irrigation water use and the groundwater exploitation showed a decreasing trend from 1977 to 2010, and was reduced by 62.5%, 44.7%, and 34.5% respectively. With the decrease in the irrigation water ratio of channel and well, the groundwater depth tended to increase gradually. The decreased precipitation, the increased evaporation, also the reduced amounts of groundwater recharge and the increased amounts of excretion all led to groundwater level dropping gradually, which dropped from 395.4 m in 1977 to 383.6 m in 2010 and the cumulative decline was 11.8 m in nearly 34 years. The simulation results of groundwater depth under different environmental scenarios showed that in scenarioⅠwith the average precipitation of 512.5 mm, the suitable irrigation water ratio of channel and well for keeping groundwater cycle healthy was 1.53. When the irrigation intake water from canal head was 2.15×108m3, and the groundwater exploitation was 1.39×108m3, so that the groundwater level could be stabilized with an average level and the balance of groundwater recharge and discharge could be maintained. In scenarioⅡ with precipitation reduced to 486.9 mm, the suitable irrigation water ratio of channel and well was 1.61. Groundwater recharge and discharge balance could be reached when the irrigation intake water from canal head was 2.19×108m3 and the groundwater exploitation was 1.36×108m3.