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1.
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
2.
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
3.
H. Pfletschinger I. Engelhardt M. Piepenbrink F. Königer R. Schuhmann A. Kallioras C. Schüth 《Environmental Earth Sciences》2012,65(5):1523-1533
For the determination of groundwater recharge processes in arid environments, vadose zone water fluxes and water storage should
be considered. To better understand and quantify vadose zone processes influencing groundwater recharge, a soil column experimental
setup has been developed that mimics arid atmospheric conditions and measures water and temperature fluxes in high temporal
and spatial resolution. The focus of the experiment was on the determination of water infiltration, redistribution, evaporation
and percolation under non-isothermal conditions. TDR rod sensors and a specific TDR “Taupe” cable sensor were used for water
content measurements and allowed the infiltration fronts to be traced over the whole column length. Applying single irrigations
of different amount and intensity showed the applicability of the experimental setup for the measurement of water movement
in the unsaturated soil column. 相似文献
4.
Advances in Moisture Migration in Vadose Zone of Dryland and Recharge Effects on Groundwater Dynamics 总被引：2，自引：0，他引：2
The vadose zone is the zone in between the land surface and above the groundwater table at vertical profile with partial water saturation and under the unsaturation condition, which constitutes the connections among atmospheric water, surface water and groundwater. Soil moisture migration in the vadose zone is a rather complicate process, which controls the rates of groundwater depletion and recharge, and has close hydraulic connections with highly frequent water transfers on the interfaces among the irrigation farmland, sand dunes, wetlands, lakes, and other landscape types. Recent development on soil moisture migration simulations and the application of tracer techniques, geophysical techniques and other geological methods in the vadose zone research, the factors affecting soil moisture migration and groundwater recharge,and soil moisture migration effects on moisture exchange between different landscapes were reviewed in this paper. Several suggestions on the future research were presented here: ① An intense field observation and research database should be initiated and constructed to determine the soil hydraulic parameters, and quantify the influence of moisture migration in vadose zone on the groundwater recharge; ② The proposed observations and researches should learn from the “Critical Zone Observatory”, and focus on the coupling of the soil moisture migration, solute transport and groundwater recharge. 相似文献
5.
谭菊萍 《前寒武纪研究进展》2013,(4):299-304
黄河冲积平原面积广大,农田灌溉频繁,灌水量大,在地下水资源评价时对灌溉入渗系数取值困难。本文在现场灌溉入渗试验的基础上,分析包气带岩性及结构、水位埋深、灌溉水量对灌溉入渗系数的影响,总结提出了多种条件下灌溉入渗系数的取值范围。在单位灌水量40～60m3／亩和水位埋深小于4m、4～8m、大于8m的井灌区中,当包气带岩性为粉土、粉砂时,灌溉入渗系数可分别取值0．21～O．10、0．10—0．05、0．05～0;当包气带岩性夹有粉质粘土层时,灌溉入渗系数可分别取值0．15～0．09、0.09—0．05、0．05～0。在单位灌水量较大的渠灌区,灌溉入渗系数可按单位灌水量的增大倍数而增加,由此为黄河冲积平原区地下水补给量计算中灌溉入渗系数的确定提供了依据。 相似文献
6.
为探讨包气带深部增厚区土壤水力参数变化对入渗补给过程的影响,采用压力膜仪对河北正定深部包气带(8.0~21.0 m)10个原状土样进行水分特征曲线测试,利用RETC软件中Mualem-van Genuchten导水率模型对其拟合,获取含水率与非饱和导水率的关系曲线,并根据达西法对其进行分析讨论.结果表明:场地包气带深埋区的非饱和导水率为25~240 mm/a.当某一埋深历史水位下降速度越快,该埋深处相同含水率情况下土壤非饱和导水率越大,说明对应土层的入渗补给强度越大;因包气带厚度增大使原来位于饱水带的层状非均质土层转变为包气带,潜水位波动下降过程中深部包气带土层因排水压密作用,使得土壤水力特性发生变化,进而影响垂向入渗补给过程. 相似文献
7.
The present research aims to derive the intrinsic vulnerability of groundwater against contamination using the GIS platform. The study applies DRASTIC model for Ahmedabad district in Gujarat, India. The model uses parameters like depth, recharge, aquifer, soil, topography, vadose zone and hydraulic conductivity, which depict the hydrogeology of the area. The research demonstrates that northern part of district with 46.4% of area is under low vulnerability, the central and southern parts with 48.4% of the area are under moderate vulnerability, while 5.2% of area in the south-east of district is under high vulnerability. It is observed from the study that lower vulnerability in northern part may be mostly due to the greater depth of vadose zone, deeper water tables and alluvial aquifer system with minor clay lenses. The moderate and high vulnerability in central and southern parts of study area may be due to lesser depth to water tables, smaller vadose zone depths, unconfined to semi-confined alluvial aquifer system and greater amount of recharge due to irrigation practices. Further, the map removal and single-parameter sensitivity analysis indicate that groundwater vulnerability index has higher influence of vadose zone, recharge, depth and aquifer parameters for the given study area. The research also contributes to validating the existence of higher concentrations of contaminants/indicators like electrical conductivity, chloride, total dissolved solids, sulphate, nitrate, calcium, sodium and magnesium with respect to groundwater vulnerability status in the study area. The contaminants/indicators exceeding the prescribed limits for drinking water as per Indian Standard 10500 (1991) were mostly found in areas under moderate and high vulnerability. Finally, the research successfully delineates the groundwater vulnerability in the region which can aid land-use policies and norms for activities related to recharge and seepage with respect to existing status of groundwater vulnerability and its quality. 相似文献
8.
受气候变化和人类活动等因素的综合影响,地下水超采和含水层水量亏空已成为备受关注的全球性问题。为了弥补含水层水量亏空和促进地下水资源涵养,已探索出多种人为干预地下水补给的措施,其中通过河道开展地下水人工补给由于具有明显优势而受到重视。已有实践表明,受渗漏补给潜力和包气带调蓄能力等的限制,并不是所有河流或河段都适宜开展地下水人工补给工作。目前缺乏为大家广泛接受的适宜性评估方法。本研究以永定河生态补水为契机,以北京平原段河道和下伏含水层为研究区开展了案例研究,并用实测数据对研究结果进行了检验。应用指标体系法建立的适宜性评估模型（LMBGITSC模型）包括河床土地利用类型、河床介质类型、河床宽度、河床地形坡度、包气带介质类型、包气带厚度、包气带给水度、包气带水平渗透性等8个指标。案例研究结果表明,沿河流流向,通过河道渗漏补给地下水的适宜性由好变差（防渗河段除外）。该规律主要受渗漏补给潜力和包气带调蓄能力控制,因此适宜性也呈现出“阶梯式”演变规律。检验结果表明所建的评估方法适用性较好。该方法具有可移植性,因此也可为其他同类地区提供参考。 相似文献
9.
为了有效提升大清河流域平原区地下水水位,亟需在此区域开展地下水人工补给工程,并确定合理的建设位置及有效的补给方式。首先基于研究区可利用补给水源、地下水位、地表高程、地表坡度及与河道距离5个指标的分布特征,构建地下水补给潜力评价体系,采用ArcGIS空间分析功能对研究区进行了地下水人工补给潜力区划;然后在此评价体系基础上,在典型人工补给高潜力区进一步开展系列野外现场试验,探讨适宜可行的地下水人工补给方式。结果表明：研究区西北部及南部河道附近区域开展人工补给工程潜力较高,而中部、北部及西南部远离河道的区域潜力较低。高潜力区——白沟引河地段包气带及含水层渗透性良好,整体渗透系数均在5 m/d左右或更高,适宜地表补给,但河床渗透性较差,渗透系数基本在0.01~0.09 m/d间,若通过河道补给需配合清淤等措施。其中,在上游及中游沿岸适宜将河道水通过生态水渠引至修建的地表入渗池或借助天然渗坑内入渗补给,在中下游沿岸区域适宜将补给水进行严格的水处理后采用井灌方式补给,在白沟引河中下游河道适宜修建拦水坝,利用河道进行入渗补给。 相似文献
10.
M. O. Schwartz 《Environmental Geology》2006,50(2):237-249
The UNSAT-H, HELP3 and MACRO4.3 computer codes, which have been developed for simulating the water balance of the unsaturated zone of soils and unconsolidated sediments, are also capable simulating water flow in low-porosity media such as fractured rock. The codes can be used to model the ability of rocks and overlying soils in the vadose zone to protect the groundwater in the uppermost aquifer. The net infiltration rates simulated by the different codes are compared against recharge determined by the chloride-balance method in Namibia. The dual-permeability code MACRO4.3 was found to produce more realistic estimates of net infiltration than the UNSAT-H and HELP3 codes, which are based on a single-permeability or effective-continuum method. The net infiltration rate together with the water storage in the unsaturated zone and the groundwater depth are used to calculate the residence time of pore water in the unsaturated zone. This parameter determines the intrinsic vulnerability of the aquifer. 相似文献
11.
Jinlong Zhou Guomin Li Feng Liu Yiping Wang Xiaojing Guo 《Environmental Earth Sciences》2010,60(5):1055-1063
According to the characteristics of groundwater in arid area, this paper proposes DRAV model for groundwater vulnerability
assessment, where D is groundwater depth, R is the net recharge of aquifer, A is the aquifer characteristics, and V is the lithology of vadose zone. As a case study, the paper assesses the vulnerability of pore phreatic water in Tarim Basin
of Xinjiang, China by using the DRAV model. The results indicate that the areas of phreatic water with vulnerability index
ranges of 2–4, 4–6, 6–8 and >8 accounting for 10.1, 80.4, 9.2 and 0.2% of the total plain area of the Tarim Basin respectively,
and the areas with the latter two vulnerability ranges (6–8 and >8) are mainly located in the irrigation districts with thin
soil layer (20–30 cm thick surface soil of vadose zone, mainly with underlying sandy gravel) and with silty and fine sand
layer. Such vadose zone generally lacks sandy loam and clayey soil and has larger recharge by infiltration of irrigation water. 相似文献
12.
The hydrogeological role of trees in water-limited environments 总被引：4，自引：1，他引：3
M. W. Lubczynski 《Hydrogeology Journal》2009,17(1):247-259
Field experiments have already proven that many tree species in water-limited environments (WLE) depend on groundwater. Typically, such trees survive dry seasons and droughts by uptake of water, directly from the groundwater body or from the capillary fringe, by rooting systems that may extend to several tens of meters depth. Such trees are also very efficient in finding soil moisture in the unsaturated zone, reducing groundwater recharge. Considering that WLE are typically characterized by low recharge, and that trees may use a significant amount of groundwater, this groundwater “consumption” should not be neglected in groundwater balancing, modeling and resources management. In practice, groundwater uptake by trees in WLE is either underestimated or disregarded because of limited knowledge about that phenomenon. This review discusses the current understanding of the hydrogeological role of trees in water-limited environments, the partitioning of tree transpiration into groundwater and unsaturated zone contributions and the integration of that partitioning in numerical groundwater models. Problems involved in this research are highlighted and possible future research directions are discussed. 相似文献
13.
Il-Moon Chung Nam-Won Kim Jeongwoo Lee Marios Sophocleous 《Hydrogeology Journal》2010,18(5):1253-1264
A method of estimating groundwater recharge, based on water-balance components using the SWAT-MODFLOW model (an integrated surface water-groundwater model), is described. A multi-reservoir storage routing module is suggested instead of a single storage routing module in SWAT; this represents a more realistic delay in the travel of water through the vadose zone. By using this module, the parameter related to the delay time can be optimized by checking the correlation between simulated recharge and observed groundwater levels. The final step of this procedure is to compare simulated groundwater levels as well as the simulated watershed stream flow with the observed groundwater levels and watershed stream flow. This method is applied to the Mihocheon watershed in South Korea to estimate spatio-temporal groundwater recharge distribution. The computed annual recharge rate is compared with the independently estimated recharge rate using BFLOW. The hydrologic modelling results show that the annual average recharge rate should be estimated by a long-term continuous simulation with a distributed hydrologic modelling technique. 相似文献
14.
Martín Hernández-Marín Lilia Guerrero-Martínez Alfredo Zermeño-Villalobos Lorena Rodríguez-González Thomas J. Burbey Jesús Pacheco-Martínez Sergio I. Martínez-Martínez Norma González-Cervantes 《Hydrogeology Journal》2018,26(8):2811-2826
The investigation involves a temporal and spatial analysis to characterize recharge in the Aguascalientes valley in central Mexico. The results are based on a two-part methodological strategy using a geospatial and numerical analysis. Results from the geospatial analysis are based on the analytical hierarchical process (AHP) method, which involves developing a zoning map that qualifies the conditions for groundwater recharge in the valley. In addition, one-dimensional numerical modeling based on the van Genuchten equation was applied for various soil column configurations to estimate the transit time of recharge through the vadose zone. The analysis was performed over a 20-year period from 1995 to 2015. The results of the geospatial analysis indicate that the optimal area for groundwater recharge is the lower zone of the valley, particularly the portion influenced by surface discontinuities. The shortest estimated period of recharge for water to pass through the vadose zone is approximately 4.25 years. 相似文献
15.
Groundwater is a very important natural resource in Khanyounis Governorate (the study area) for water supply and development.
Historically, the exploitation of aquifers in Khanyounis Governorate has been undertaken without proper concern for environmental
impact. In view of the importance of quality groundwater, it might be expected that aquifer protection to prevent groundwater
quality deterioration would have received due attention. In the long term, however, protection of groundwater resources is
of direct practical importance because, once pollution of groundwater has been allowed to occur, the scale and persistence
of such pollution makes restoration technically difficult and costly. In order to maintain basin aquifer as a source of water
for the area, it is necessary to find out, whether certain locations in this groundwater basin are susceptible to receive
and transmit contamination. This study aims to: (1) assess the vulnerability of the aquifer to contamination in Khanyounis
governorate, (2) find out the groundwater vulnerable zones to contamination in the aquifer of the study area, and (3) provide
a spatial analysis of the parameters and conditions under which groundwater may become contaminate. To achieve that, DRASTIC
model within geographic information system (GIS) environment was applied. The model uses seven environmental parameters: depth
of water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity to
evaluate aquifer vulnerability. Based on this model and by using ArcGIS 9.3 software, an attempt was made to create vulnerability
maps for the study area. According to the DRASTIC model index, the study has shown that in the western part of the study area
the vulnerability to contamination ranges between high and very high due to the relatively shallow water table with moderate
to high recharge potential, and permeable soils. To the east of the previous part and in the south-eastern part, vulnerability
to contamination is moderate. In the central and the eastern part, vulnerability to contamination is low due to depth of water
table. Vulnerability analysis of the DRASTIC Model indicates that the highest risk of contamination of groundwater in the
study area originates from the soil media. The impact of vadose zone, depth to water level, and hydraulic conductivity imply
moderate risks of contamination, while net recharge, aquifer media, and topography impose a low risk of aquifer contamination.
The coefficient of variation indicates that a high contribution to the variation of vulnerability index is made by the topography.
Moderate contribution is made by the depth to water level, and net recharge, while impact of vadose zone, hydraulic conductivity,
soil media, and Aquifer media are the least variable parameters. The low variability of the parameters implies a smaller contribution
to the variation of the vulnerability index across the study area. Moreover, the “effective” weights of the DRASTIC parameters
obtained in this study exhibited some deviation from that of the “theoretical” weights. Soil media and the impact of vadose
zone were the most effective parameters in the vulnerability assessment because their mean “effective” weights were higher
than their respective “theoretical” weights. The depth of water table showed that both “effective” and “theoretical” weights
were equal. The rest of the parameters exhibit lower “effective” weights compared with the “theoretical” weights. This explains
the importance of soil media and vadose layers in the DRASTIC model. Therefore, it is important to get the accurate and detailed
information of these two specific parameters. The GIS technique has provided an efficient environment for analysis and high
capabilities of handling large spatial data. Considering these results, DRASTIC model highlights as a useful tool that can
be used by national authorities and decision makers especially in the agricultural areas applying chemicals and pesticides
which are most likely to contaminate groundwater resources. 相似文献
16.
Henao Casas José D. Kalwa Fritz Walther Marc Rausch Randolf 《Hydrogeology Journal》2021,29(5):1813-1830
To cope with water scarcity in drylands, stormwater is often collected in surface basins and subsequently stored in shallow aquifers via infiltration. These stormwater harvesting systems are often accompanied by high evaporation rates and hygiene problems. This is commonly a consequence of low infiltration rates, which are caused by clogging layers that form on top of the soil profile and the presence of a thick vadose zone. The present study aims to develop a conceptual solution to increase groundwater recharge rates in stormwater harvesting systems. The efficiency of vadose-zone wells and infiltration trenches is tested using analytical equations, numerical models, and sensitivity analyses. Dams built in the channel of ephemeral streams (wadis) are selected as a study case to construct the numerical simulations. The modelling demonstrated that vadose-zone wells and infiltration trenches contribute to effective bypassing of the clogging layer. By implementing these solutions, recharge begins 2250–8100% faster than via infiltration from the bed surface of the wadi reservoir. The sensitivity analysis showed that the recharge rates are especially responsive to well length and trench depth. In terms of recharge quantity, the well had the best performance; it can infiltrate up to 1642% more water than the reservoir, and between 336 and 825% more than the trench. Moreover, the well can yield the highest cumulative recharge per dollar and high recharge rates when there are limitations to the available area. The methods investigated here significantly increased recharge rates, providing practical solutions to enhance aquifer water storage in drylands.
相似文献17.
18.
西北内陆流域下游区天然植被对地下水生态功能具有强烈依赖性,而包气带岩性结构对地下水生态功能具有明显影响,但是在目前的研究中,缺乏定量分析评判。以甘肃石羊河流域下游天然绿洲区为研究区,基于包气带岩性结构野外调查、室内土柱试验和Hydrus1-D数值模拟,研究包气带岩性结构与地下水耦合作用的生态效应,分析不同岩性结构包气带... 相似文献
19.
The aquifer vulnerability of the Molototsi (B81G) and Middle Letaba (B82D) quaternary catchments was assessed to determine the influence of the vadose zone on the groundwater regime. The aquifer vulnerability was assessed by developing a new method, which evaluates the vadose zone as a pathway for pollutants using the following four parameters: recharge, depth to water table, soil type (saturated vertical hydraulic conductivity) and slope (RDSS). Recharge was estimated using the chloride mass balance method, and the depth to the water table was measured in the field using dipmeter. The seepage behaviour (soil type) was determined as hydraulic conductivity from in situ infiltration and percolation testing (SABS 0252-2:1993 and double ring infiltrometer). The slopes were determined with the digital elevation method using ArcGIS software. The four parameters were overlaid using weighted sum, weighted overlay and raster calculator to produce the vulnerability map. Different weightings were attributed in the methods and the best selected. The results obtained indicated high vulnerability on the lower and upper parts of both catchments. The benefits of the method described are (a) the easy quantification of the parameters through fairly simple methods and (b) the exclusion of arbitrary index values. 相似文献
20.
干湿交替的回灌方法常被用于解决地面回灌补给地下水的堵塞问题。研究干湿交替条件下地面回灌对地下水的影响对于指导再生水回灌地下水具有重要实际意义。通过室内土柱模拟实验,在入渗强度为10.5 mm/h的条件下,日均进水量3 888 mL;用干湿交替的地面回灌模式持续运行136 d,累计灌入氨氮含量为5 mg/L的模拟再生水23 894 L,研究包气带土柱对氨氮的去除效果及氮素在包气带中的迁移转化规律。研究表明,充分利用包气带的好氧、兼氧和厌氧环境,生物脱氮是地下水回灌过程中脱氮的主要途径。包气带对氨氮的去除机理主要为土壤对氨氮的吸附作用和微生物的降解作用。回灌过程中累积在土颗粒表面的氨氮在干期发生硝化作用,干湿交替会加强氮素在包气带的迁移转化,导致干期后的回灌初期大量硝态氮迁移到饱和带地下水中。 相似文献