利用地下水水位波动提取地下水蒸发蒸腾和降雨入渗补给强度

发布时间：2019-02-26 18:55

【摘要】：蒸发蒸腾是干旱和半干旱地区浅埋藏地下水最主要的排泄方式,而降雨是地下水的主要补给方式。两者均是地下水系统中最重要的均衡项,这两项的精确估算在地下水资源评价、地下水的合理开发和植被保护等方面起着重要作用。本文以陕西宝鸡渭河南岸黄土区为研究区,选取了7个具有代表性的观测井,获得了为时一年的高频率地下水水位监测数据。在此基础上,分析了地下水位的变化规律,利用地下水水位波动法逐一分离净补给和气压效应引起的水位变化量,消除利斯效应,分别获取了蒸发蒸腾强度和降雨入渗补给强度的估算方法。并利用水量均衡法验证了这两种估算方法是准确可靠的。研究取得了以下主要成果:(1)地下水的侧向净补给引起的地下水位的变化整体呈现出“夏季多,冬季少”的趋势,最大值出现在9月为4.96 cm/d,最小值出现在1月为1.41 cm/d,春季补给平稳。(2)气压效应在研究区显著,是影响地下水水位波动的重要因素。水位对气压响应的滞后特征,观测井水位滞后时间在0~80分钟不等。气压效应系数的可信区间为(-0.558,-0.442)。在本研究区内,气压效应引起的水位变化量在浅水位区比较大,深埋深区比较小,也可以初步的判定该区域水位能受到气压效应影响的深度约小于3.5 m。(3)蒸发蒸腾强度的年内变化由7个观测井的数据来体现,可以简单描述为“夏高春低,秋高冬低”,5、6、7、8月份最高。(4)地下水水位对降雨事件存在响应延迟效应。地下水水位对降雨事件的响应延迟时间与降雨事件的发生情况、降雨强度的大小、水位埋深等因素有关。长时间未降雨后的第一次降雨,水位的响应延迟时间较长。水位埋深越大,水位的响应延迟时间越长。降雨强度越大,水位的响应时间越短。(5)6个有效观测井的年均降雨入渗补给系数分别为0.37、0.29、0.64、0.39、0.43、0.23。整体表现为,久旱后的首场雨的补给系数很小或为0,随着降雨陆续的发生降雨入渗补给系数增大。降雨入渗补给地下水存在持续效应,在研究时段内,降雨的持续时间在5-40天不等。
[Abstract]:Evaporation and transpiration is the most important discharge mode of shallow groundwater in arid and semi-arid areas, and rainfall is the main way to replenish groundwater. Both of them are the most important equilibrium terms in groundwater system, and the accurate estimation of these two items plays an important role in the evaluation of groundwater resources, the rational exploitation of groundwater and the protection of vegetation and so on. In this paper, 7 representative observation wells were selected from the loess area on the south bank of Weihe River in Baoji, Shaanxi Province, and the monitoring data of high frequency groundwater level for one year were obtained. On the basis of this, the variation rule of groundwater level is analyzed, and the water level change caused by net replenishment and barometric effect is separated one by the method of groundwater level fluctuation, so as to eliminate the Liss effect. The estimation methods of evaporation and transpiration intensity and rainfall infiltration recharge intensity were obtained respectively. The water balance method is used to verify that the two methods are accurate and reliable. The main results are as follows: (1) the variation of groundwater level caused by lateral net recharge of groundwater shows the trend of "more summer and less winter", and the maximum value is 4.96 cm/d, in September. The minimum value was 1.41 cm/d, in January. (2) the barometric effect was significant in the study area, which was an important factor affecting the fluctuation of groundwater level. The lag time of water level response to air pressure varies from 0 to 80 minutes. The confidence interval of barometric effect coefficient is (- 0.558, / 0.442). In this study area, the change of water level caused by barometric effect is larger in shallow water level area, and smaller in deep buried area. It can also be preliminarily determined that the depth at which the water level in this area can be affected by the barometric effect is less than 3.5 m. (3) the annual variation of evapotranspiration intensity is reflected by the data from seven observation wells, which can be simply described as "high summer and low spring." Autumn is high and winter is low ", 5,6,7 and August are the highest. (4) the response of groundwater level to rainfall events is delayed. The response delay time of groundwater level to rainfall events is related to the occurrence of rainfall events, the magnitude of rainfall intensity, the depth of water level and other factors. For the first rainfall without rainfall for a long time, the response delay time of the water level is longer. The greater the depth of the water level, the longer the delay time of the response of the water level is. The higher the rainfall intensity, the shorter the response time of the water level. (5) the annual rainfall infiltration replenishment coefficients of the six effective observation wells are 0.37, 0.29, 0.64, 0.39, 0.43, 0.23 respectively. As a whole, the replenishment coefficient of the first rain after a long drought is very small or 0, and the replenishment coefficient of rainfall infiltration increases with the occurrence of rainfall one after another. Rainfall infiltration recharge groundwater has a persistent effect, during the study period, the duration of rainfall is not equal to 5-40 days.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P641

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