共查询到18条相似文献，搜索用时 154 毫秒
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降水入渗补给系数分析研究 总被引：4，自引：0，他引：4
本文运用均衡实验站各观测系统的实验数据和资料,根据水均衡原理和"三水"转换关系,通过包气带蓄水库容有效作用分析,阐明了包气带蓄水库容和复蓄的概念,说明了包气带对土壤中水分调节作用的机理.通过对前期影响雨量系列的分析,建立了降水与入渗补给系数之间的关系,得出了降水入渗补给系数计算思路和取值公式,同时就降水入渗补给系数和地下水埋深的关系进行了探索. 相似文献
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确定干旱—半干旱地区降水入渗补给量的新方法——氯离子示踪法 总被引：7，自引：0，他引：7
在干旱－半干旱地区由于入渗水分大部分滞留在包气带中，强烈地蒸发、蒸作用导致包气带中土壤水的氯离子浓度改变。氯离子示踪方法从质量守恒角度，通过比较土壤水分的氯离子浓度和降水输入的氯离子浓度大小，可以定量确定降水入渗量和降水入渗补给的历史变化过程。本文介绍了目前国外应用较普遍的氯离子均衡法和氯离子累积法，并讨论了方法应用时存在的一些问题。 相似文献
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种植条件下降雨灌溉入渗试验研究 总被引：2，自引：0，他引：2
基于清水河平原头营和黑城试验场降雨(灌溉)入渗过程土壤水分运移观测试验数据的分析研究,笔者应用能量观点描述了包气带水分运移的分带性、降雨(灌溉)入渗补给地下水的水分条件和地下水入渗补给过程的基本特征。应用蒸散量模型、土壤水分通量模型,计算了作物生长期的蒸发蒸腾量、土壤贮水量的变化量、400cm深度处的土壤水分渗漏量及渗漏系数。从多年的角度分析了深层土壤水分渗漏量、渗漏系数与地下水入渗补给量和补给系数的关系。它对分析降雨(灌溉)入渗对地下水的补给过程和定量分析地下水入渗补给量、入渗补给系数具有重要价值。 相似文献
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大气降雨是华北平原浅层地下水的主要补给来源。长期过量开采地下水造成地下水位持续下降,使原来处于饱水带的透镜体位移到包气带中,形成了厚度大、非均质性更为复杂的包气带。厚层包气带中弱渗透性黏土透镜体对于降雨入渗补给的影响是关系到降水入渗过程及补给量评价的基本问题。用HYDRUS软件建立数值模拟模型,模拟探讨单次降雨条件下,透镜体埋深、宽度比、厚度等要素对入渗路径、入渗补给时间和入渗补给量的影响。结果表明:入渗过程中弱渗透性黏土透镜体两侧会形成较快的绕流;透镜体会减小补给峰值并延长总体补给时间,但不改变补给起始时间;透镜体埋深与极限蒸发深度的相对关系决定了潜在补给量的大小,透镜体埋深或因透镜体形成的上层滞水处于极限蒸发深度以上会减少潜在补给量。 相似文献
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利用包气带环境示踪剂评估张掖盆地降水入渗速率 总被引：2，自引：0，他引：2
降水入渗补给速率是干旱半干旱地区地下水资源评价和保护中的重要参数。长期以来在河西走廊中游盆地地下水资源评价中,一直认为地下水位埋深>5m的地带难以产生降水入渗补给。本文在黑河流域中游的张掖盆地分别选择沙丘区和裸地区,综合运用包气带同位素和水化学信息,开展了降水入渗补给研究。包气带氯质量平衡法结果表明:现代气候条件下,张掖盆地地下水位埋深>5m的地带仍存在降水入渗补给,在沙丘覆盖区,地下水位埋深6.3m时,降水入渗补给速率为13.3～14.4mm/a,入渗系数0.10～0.11;在裸地区,地下水位埋深8.6m时,降水入渗补给速率为16.8～18.4mm/a,入渗系数0.13～0.14。 相似文献
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降水和人工灌溉是黑河中游浅层地下水重要的补给来源。长期以来入渗补给量评价采用经验参数法,但没有成熟的监测方法和实证数据。采用人工溴示踪法研究黑河中游不同灌溉条件和不同深度条件下的地下水入渗补给规律。结果表明:研究区大气降水条件下包气带溴离子含量峰值年均运移距离为21.25 cm,年平均入渗补给量为11.93 mm,入渗补给系数为0.1;大水漫灌条件下包气带溴离子含量峰值年均运移距离为86.51 cm,年平均入渗补给量为148.7 mm,入渗补给系数为0.16;小水漫灌条件下包气带溴离子含量峰值年均运移距离为46.35 cm,年平均入渗补给量为 53.81 mm,入渗补给系数为0.07;滴灌条件下年包气带溴离子含量峰值年均运移距离为41.72 cm,年平均入渗补给量为52.6 mm,入渗补给系数为0.11。人工溴示踪剂应投放在包气带水分单向入渗下行区,一般西北内陆盆地在地表3 m以下为宜。此研究成果可为黑河流域地下水资源评价提供实证参数,对西北内流盆地地下水水资源量与合理开发利用的科学认识具有重要意义。 相似文献
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在地下水资源评价或地下水动态研究过程中,降水入渗系数α,是一个经常要用到的重要水文地质参数,影响它的因素很多,除降水本身的因素外,主要还有地形地貌、包气带岩性及地下水位埋深(即包气带厚度)。 相似文献
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准确计算地下水的垂向入渗补给量是合理评价和利用地下水资源的基础.EARTH模型是一种集中参数的水文模型,可刻画水流在包气带中的运移过程,弥补黑箱模型的不足.以中国科学院栾城农业生态试验站的地下水位观测资料以及气象资料为基础,综合运用降水、蒸发、土壤水、地下水动态观测资料,利用EARTH模型计算了河北平原地下水垂向入渗补给量.计算结果表明,2003年1月1日至2005年8月31日期间,栾城农业生态试验站在降水量1404.1 mm、灌溉量1050.0 mm的条件下地下水入渗补给量为487.2 mm,平均年入渗补给量为182.6 mm, 占降水和灌溉总量(2454.1 mm)的19.9%.在模拟结果的基础上,对不同年份的降水量(含灌溉)和入渗补给量分布的对比分析表明,河北栾城地下水补给滞后现象明显,在研究时间段内峰值滞后18～35 d. 相似文献
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华北平原地下水浅埋区水循环主要以垂直方向上的入渗、蒸发和蒸腾的方式存在,同位素可以作为一种有效"示踪剂"揭示降水入渗补给地下水的过程。选择华北平原中、东部地下水浅埋区的衡水和沧州为典型实验点,研究不同降水特征、土壤质地和植被条件下入渗过程的差异性。结果表明,土壤非均质条件下(沧州),降水入渗补给过程中伴随着蒸发、植被蒸腾作用以及与土壤前期水分的强烈混合作用,活塞流入渗的同时土壤100 cm深度可能还存在大孔隙优先流;土壤均质条件下(衡水),降水向下均匀入渗,入渗速度较快,土壤水运动以新水基本代替老水的活塞流为主要形式,并经过强烈的蒸发浓缩作用补给地下水。 相似文献
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地表-地下水系统水、热迁移转化与裸土蒸发机理研究对于水量平衡以及地表能量转化具有重要意义。以鄂尔多斯盆地风沙滩地区为研究区,基于原位蒸渗仪长期观测,结合数值模拟,选择2种地下水位初始埋深分别为80 cm（浅埋深）和290 cm（深埋深）的情景,研究了变饱和带水热迁移转化的动力学过程以及对裸土蒸发的影响。结果表明:变饱和带土壤水的运动规律受水头梯度和温度梯度的共同驱动,且在不同水位埋深条件下呈现不同的运动方式;浅埋深条件下,受水头梯度的作用,土壤的毛细上升高度能够到达地表,蒸发条件下土壤水在毛细力驱动下向上运移,土壤内部不存在零通量面,温度对水分运动的影响较小,发现当地下水位埋深小于毛细上升高度时,地下水在毛细力作用下直接贡献土壤蒸发;深埋深条件下,水头和温度是土壤水运动过程的关键因素,位于地表以下18 cm以浅土壤内部出现孤立的零通量面,阻止了土壤水的向上运移,导致蒸发量减小。当地下水位埋深大于毛细上升高度的1.6倍时,地下水不再直接参与土壤蒸发,但会间接地影响包气带的水分转化;因此模拟期间浅埋深的裸土累积蒸发量约为深埋深累积蒸发量的4倍。 相似文献
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Evaporation capacity is an important factor that cannot be ignored when judging whether extreme precipitation events will produce groundwater recharge. The evaporation layer’s role in groundwater recharge was evaluated using a lysimeter simulation experiment in the desert area of Dunhuang, in the western part of the Hexi Corridor in northwestern China’s Gansu Province. The annual precipitation in the study area is extremely low, averaging 38.87 mm during the 60-year study period, and daily pan evaporation amounts to 2,486 mm. Three simulated precipitation regimes (normal, 10 mm; ordinary annual maximum, 21 mm; and extreme, 31 mm) were used in the lysimeter simulation to allow monitoring of water movement and weighing to detect evaporative losses. The differences in soil-water content to a depth of 50 cm in the soil profile significantly affected rainfall infiltration during the initial stages of rainfall events. It was found that the presence of a dry 50-cm-deep sand layer was the key factor for “potential recharge” after the three rainfall events. Daily precipitation events less than 20 mm did not produce groundwater recharge because of the barrier effect created by the dry sand. Infiltration totaled 0.68 mm and penetrated to a depth below 50 cm with 31 mm of rainfall, representing potential recharge equivalent to 1.7 % of the rainfall. This suggests that only extreme precipitation events offer the possibility of recharge of groundwater in this extremely arid area. 相似文献
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This study aims to estimate artificial recharge of groundwater by using remote sensing technology, geographical information systems, and groundwater surveys. This study is part of the King Fahd project for rainfall and runoff water harvesting, within the premises of Alilb Dam in Diriyah to the west of Riyadh. Digital elevation models were obtained with the help of aerial photography from the year 2007. These models were used to delineate watershed. Average rainfall was calculated using isoheytal method, and the area of each of the storage lakes was measured using SPOT 5 satellite images from 2007. Fluctuations in groundwater levels, evaporation, and infiltration rates were used to determine the water balance for the purpose of estimating of artificial recharge. Artificial recharge rates were found to surpass natural recharge from rainfall. Recharge wells caused a reduction in the effect of evaporation on storage lakes and helped in supplying water to the groundwater reservoir. Moreover, 80% and 86% of the rainwater was found to be available for artificial recharge in Alilb at 2005 and 2007, respectively. The study recommends the establishment of strategic projects for water storage using artificial recharge wells, an increase in the number of monitoring wells around the dams, and the monitoring of hydrochemical changes in groundwater both before and after the artificial recharge. It also recommends the erection of a weather station in the northwest of Wadi Hanifa. 相似文献
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太行山山前平原地下水补给规律分析:以河北栾城为例 总被引：2，自引：0，他引：2
采用水均衡法与通量法对太行山山前平原(河北栾城)进行了地下水补给评价,结果表明:近20 a地下水入渗补给量为8～172mm/a(水均衡法),平均值49.3 mm/a,变化幅度大.其中2004年入渗补给量(63mm/a)比采用通量法计算结果(28.2mm/a)大一倍,表明土壤优先流对入渗补给作用显著.年入渗补给量总体上随有效降雨量增加、地下水位下降速率减少、作物实际蒸发蒸腾量减少而增加,但与有效灌溉量和灌溉量之和的相关性不显著.通过长序列地下水位与灌溉量等数据估算得到研究区侧向净补给量为125.2 mm/a,约占地下水总补给量的71.7％(175.4 mm/a),说明地下水主要以侧向补给为主.同时计算了入渗补给与侧向补给地下水的延迟时间,分别为60 a和1个月. 相似文献
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《China Geology》2020,3(3):462-472
The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain, the transition zone between the Dabie Mountain Area and Jianghan Plain. It’s a great field test site to study the material and energy exchange among rainfall, soil moisture, and groundwater of the Earth ’s critical zone in subtropical monsoon climate plain areas. This paper analyzed the connection between rainfall and volume water content (VWC) of soil at different depths of several soil profiles, and the dynamic feature of groundwater was discussed, which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata. The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge, while the lateral recharge is the main supplement source. There were 75 effective rainfall events among 120 rainfall events during the monitoring period, with an accumulated amount of 672.9 mm, and the percentages of effective rainfall amount and duration time were 62.50% and 91.56%, respectively. The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m. The soil profile was divided into four zones: (1) The sensitive zone of rainfall infiltration within 1.4 m, where the material and energy exchange frequently near the interface between atmosphere and soil; (2) the buffer zone of rainfall infiltration between 1.4 m and 3.5 m; (3) the migration zone of rainfall infiltration between 3.5 m and 5.0 m; and (4) the rainfall infiltration and groundwater level co-influenced zone below 5.0 m. The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth ’s critical zone, which is of great theoretical and practical significance for groundwater resources evaluation and development, groundwater environmental protection, ecological environmental improvement, drought disaster prevention, and flood disaster prevention in subtropical monsoon climate plain areas. 相似文献
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Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate 总被引：3，自引：2，他引：1
D. J. Lapworth A. M. MacDonald M. N. Tijani W. G. Darling D. C. Gooddy H. C. Bonsor L. J. Araguás-Araguás 《Hydrogeology Journal》2013,21(3):673-686
Although shallow groundwater (<50 mbgl) sustains the vast majority of improved drinking-water supplies in rural Africa, there is little information on how resilient this resource may be to future changes in climate. This study presents results of a groundwater survey using stable isotopes, CFCs, SF6, and 3H across different climatic zones (annual rainfall 400–2,000 mm/year) in West Africa. The purpose was to quantify the residence times of shallow groundwaters in sedimentary and basement aquifers, and investigate the relationship between groundwater resources and climate. Stable-isotope results indicate that most shallow groundwaters are recharged rapidly following rainfall, showing little evidence of evaporation prior to recharge. Chloride mass-balance results indicate that within the arid areas (<400 mm annual rainfall) there is recharge of up to 20 mm/year. Age tracers show that most groundwaters have mean residence times (MRTs) of 32–65 years, with comparable MRTs in the different climate zones. Similar MRTs measured in both the sedimentary and basement aquifers suggest similar hydraulic diffusivity and significant groundwater storage within the shallow basement. This suggests there is considerable resilience to short-term inter-annual variation in rainfall and recharge, and rural groundwater resources are likely to sustain diffuse, low volume abstraction. 相似文献
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Lihe Yin Guangcai Hou XiaoSi Su Dong Wang Jiaqiu Dong Yonghong Hao Xiaoyong Wang 《Hydrogeology Journal》2011,19(2):429-443
The characteristics of δD and δ18O in precipitation, groundwater and surface water have been used to understand the groundwater flow system in the Ordos Plateau, north-central China. The slope of the local meteoric water line (LMWL) is smaller than that of the global meteoric water line (GMWL), which signifies secondary evaporation during rainfall. The distribution of stable isotopes of precipitation is influenced by temperature and the amount of precipitation. The lake water is enriched isotopically due to evaporation and its isotopic composition is closely related to the source of recharge and location in the groundwater flow systems. River water is enriched isotopically, indicating that it suffers evaporation. The deep groundwater (more than 150?m) is depleted in heavy isotopes relative to the shallow groundwater (less than 150?m), suggesting that deep groundwater may have been recharged during the late Pleistocene and early Holocene, when the climate was wetter and colder than at present. All groundwater samples plot around the LMWL, implying groundwater is of meteoric origin. Shallow groundwater has undergone evaporation and the average evaporation loss is 53%. There are two recharge mechanisms: preferential flow, and the mixture of evaporated soil moisture and subsequent rain. 相似文献
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地下水的补排主要包括垂向的地面入渗补给、蒸发排泄（蒸发可视为入渗的负值）及侧向的地表水补给、排泄。水文地质学最基本的问题之一——地下水可持续开釆量的评价准则,涉及补给的增量与排泄的减量,因此地下水开采的预测模型必须包含上述两类的补给、排泄因素,否则不能满足要求。然而,经典的Theis不稳定井流模型,即使在傍河抽水,也只有侧边界的补给、排泄作用,而不涉及上边界的地面入渗补给。这样一来,这个解析模型基本上不能够用于预测,而只能在旱季用于井流试验求取含水系统的参数。为此,文章的目标是发展具地面入渗补给的Theis不稳定潜水井流模型。对于潜水流问题,不能再用承压水流的以水头为应变量的方程来建立,应采用第二类线性化方法的势函数来建立潜水流问题。对于既有降雨入渗补给,又有抽水井作用的复杂的水文地质问题所概化数学模型的求解,采取的方法是把它分解成若干个简单的子模型问题求解,然后将其合成为原来复杂数学模型的解。基于质量守恒原理,假定渗流服从Darcy定律并满足Dupuit徦定建立了水流基本微分方程。然后对于两平行河流及一河流平行一隔水边界形成的两类条形区域,具地面均匀稳定入渗补给的井流问题,获得通用水位方程和几类常见的特定条件水位方程及其流量方程。此外,提出并采用“边界对边界的反映法”用以求解一河流平行一隔水边界条形区域的同一问题,减少了许多推导过程。最后,作为上述理论成果的初步应用,也是一个重要的应用,即在河水水质不能满足要求的河流附近,设有一口抽水井,计算该抽水井在不汲取河水的前提下的临界流量方程,获得具重要意义的结构简洁的关系式。该方程也可以用于滨海区的抽水井,在不发生海水入侵前提下的临界抽水流量计算。给出了上述条件不稳定井流过程某时刻的地下水流网图,其流网与文献中常见的傍河井流的流网相比,具显明的特征。 相似文献