Estimating Regional Groundwater Recharge Using a Hydrological Budget Method

Estimating groundwater recharge is a key component in determining the sustainable yield of groundwater resources in arid and semi-arid areas such as southern California. Estimating groundwater recharge on a regional scale requires developing a water budget that incorporates data on boundary conditions, aquifer properties, groundwater levels, and groundwater production. The hydrological budget method proposed herein is simple, cost-effective, and easy to apply. It utilizes matched pairs of groundwater level measurements, groundwater extraction data, and distributed specific yield information for estimating groundwater recharge. In this method, ARCGIS 9.0 Geostatistical and Spatial Analyst applications are used for interpolating/extrapolating and creating grids for specific yield, bedrock elevation, and raw groundwater data. The annual average groundwater recharge for the Hemet subbasin in western Riverside County, California, from 1997 to 2005 is estimated at 12.5 MCM, with wet and dry periods ranging between 14.9 MCM and 11.7 MCM, respectively. The proposed method utilizes information commonly available to most groundwater management entities, such as groundwater production data, groundwater level measurements, and lithologic information.     

Optimal Operation of Artificial Groundwater Recharge Systems Considering Water Quality Transformations

In water limited areas as water demand increases alternative sustainable water sources must be identified. One supply augmentation practice, that is already being applied in the arid southwest U.S., is artificial groundwater recharge usingwastewater effluent. The objective of a recharge facility is to supplement the available groundwater resources by storing water for the future. The resulting reclaimed water is used primarily for non-potable purposes but under increasing stressesshifting to potable use is likely to happen. Water quality thenbecomes a more pressing concern. Water quality improvements during infiltration and groundwater transport are significant and are collectively described as soil-aquifer treatment (SAT). To meet user needs, the recharge operation must be efficiently managed considering monetary, water quality and environmental concerns. In this paper, a SAT management model is developed that considers all of these concerns. Within the SAT management model, the shuffled complex evolution algorithm (SCE) is used as the optimization tool. SCEis a relatively new meta-heuristic search technique for continuousproblems that has been used extensively for hydrologic model calibration. In this application, SCE is integrated with the simulation models (MODFLOW, MT3D, and MODPATH) to represent movement and quality transformations. Two steady state case studies on a general hypothetical aquifer (modeled after a field site) were examined using the management model.     

潜水入渗补给研究进展

目前,对土壤水运移机理研究已从定性走向定量、从均质走向非均质。优先流是地下水入渗的普遍现象,在田间土壤水主要以捷径流方式入渗补给地下水。对优先流研究是潜水入渗补给研究的重点与难点之一,其主要方法为染色示踪与X射线成像和地质雷达技术。潜水入渗补给评价方法众多,且每种方法都有其适用条件。因此,综合采用示踪法、地下水位波动法、地中渗透仪法、零通量法和数值模拟法,相互对比验证,提高评价可靠性,是研究地下水入渗补给最有效的方法。     

Groundwater Resources Sustainability: Past, Present, and Future

With the worldwide depletion of groundwater and the intensified use around the world, particularly in many arid and semi-arid regions for irrigation and municipal use, there is no satisfactory approach to groundwater sustainability. The lack of and miss-management of this valuable resource has not only created serious groundwater pollution problems but has created present and/or future water supply problems. This paper does not present a solution, but instead examines economic ideas such as exhaustible resource theory (over exploitation), and optimization methodologies that can incorporate new ideas of groundwater sustainability, population growth constraints, include both short term and long term consequences, and consider multi-objectives. Concepts of groundwater footprint, recharge, and safe yield are discarded as concepts for measuring groundwater sustainability. The concept of developing a sustainability index that could also be used within the context of optimization is introduced. Also the concepts of traditional knowledge are discussed with the emphasis on the use of these methodologies for both developed and developing regions of the world to achieve groundwater sustainability.     

反滤回灌井的改进技术

反滤回灌井是我国山东半岛地下水回灌中广泛采用的一种有效的回灌设施,它由回灌井和回灌池组成。文中分析了反滤回灌井的利用现状及存在的主要问题,提出了综合改进措施,研发了土工织物反滤回灌井技术,并导出土工织物反滤回灌井单井回灌量的理论计算公式。     

不同回灌补源模式下石川河富平地下水库数值模拟

石川河富平地区地下水长期处于采补失衡状态,大范围含水层被疏干,形成区域性降落漏斗,针对拟建的石川河富平地下水库,设置5种开采回灌方案,建立地下水流数值模型模拟不同方案下地下水库水位和蓄水库容变化情况。结果表明：各回灌方案在消除降落漏斗的同时,均能较好地恢复地下水水位,且不超过地下水库的调蓄上限水位;回灌量相同、回灌方式不同时,逐日回灌方式的水位恢复效果优于灌期+非灌期回灌方式,较2018年地下水水位平均抬升13.55 m,蓄水库容增加2.99×10⁸ m³;回灌量不同时,较大回灌量对地下水水位的影响大于回灌方式,即泾惠渠水源回灌时,水位抬升程度最大,为19.77 m,蓄水库容相应增加4.36×10⁸ m³。模拟结果可为地下水库的调蓄与运行提供参考。     

平原漏斗区高效生态含水层补给技术研究

针对中国黄泛平原井灌地区地下水超采引起的大面积地下水漏斗问题,选择山东省临清市项目区,利用土壤水动力学、水力学和地下水动力学等相关理论,实施了地下水回灌工程对技术方案和参数进行设计,计算其回灌效果。通过计算结果可知,该回灌工程在7 d的引水过程中,增加了52 310.82 m~3的地下水补给量,占地下水补给总量的60.7%。野外回灌系统流速监测和示踪试验表明,该工程设计方案可行。在原沟渠渗入补给的基础上,该种明沟—暗管—竖井回灌补源工程增加了地下水补给量,对地下水漏斗恢复和旱涝碱综合治理具有重要作用。     

气候变化情景下的地下水潜在补给变化影响分析——以栾城试验站为例

了解气候变化影响下的地下水潜在补给变化对于地下水资源的科学管理与评价是非常必要的。以栾城生态试验站为典型研究区,联合应用ClimGen天气发生器和地下水补给Visual HELP模型,对未来气候变化情景下的地下水潜在补给速率进行了评估。结果显示:在降水减少10%(P)、温度上升2℃(T)以及两者同时发生(PT)三种情景下,未来(2011年-2040年)地下水多年平均补给速率相比基准(1961年-1990年)分别下降了23.33%、4.42%、26.01%,其中降水的减少对地下水入渗补给的影响尤为明显。该项研究对于指导地下水资源的科学管理与可持续开发利用具有重要意义。     

土壤水入渗补给数值模拟——以河北栾城为例

由于通过短时间尺度的土壤水动态监测数据难以准确获得土壤水入渗补给的规律,因此在中国地质科学院栾城试验场开展了长时间尺度(5 a)的土壤水动态监测试验,监测深度为340 cm。利用Hydrus-1D软件的双渗透(基质流区和大孔隙流区)模型进行数值模拟,并采用最小函数法对模型进行参数反演。为克服地表复杂的气象条件可能给模拟结果带来较大误差,选取140 cm深度为模型上边界。研究结果表明,基质流区(m)和大孔隙流区(F)土壤水动力特征参数n_m,n_F,α_m和α_F,大孔隙流区饱和导水系数K_sF对模型入渗补给量的灵敏性最高,并被选取为模型反演参数。 总体上,土壤体积含水量的模拟值能较好地拟合其实测值,其决定系数为0.78。地下水入渗补给速率具有年际变化特征,但在年内具有明显的季节性,即在雨季达到最大,然后缓慢减小。年均入渗补给速率为220 mm/a,其中由优先流引起的入渗补给量为211 mm/a,这表明地下水入渗补给以优先流为主。该研究成果可提高对地下水入渗补给规律的认识,同时可为地下水资源评价与农业节水管理等提供参考。     

济南泉域地下水保护对策探析

济南泉域是典型的单斜构造,裂隙岩溶发育,地下水丰富,泉水众多。为保护好济南泉域地下水,保持"泉城"特色,从分析泉域地质及水文地质条件、地下水开发利用现状及存在问题出发,提出回灌补源、分质供水、开源节流、禁采限采、经济调节、管理与监测等工程措施和非工程措施。     

滹沱河大型入渗试验地下水补给量计算

通过采用水均衡法计算了滹沱河入渗试验期间的河道入渗补给量,并求取了滹沱河水源地一带获得的河道入渗补给量。研究表明:试验期间河道入渗水量为1 482.75万m3,河道入渗补给地下水量为1 382.89万m3,河道渗漏补给系数为93%;滹沱河水源地接受的补给量为742.53万m3,水源地范围内的观测井最大水位上升幅度6.823m,地下水补给效果明显。     

Estimating Land Use Impacts on Regional Scale Urban Water Balance and Groundwater Recharge

Anthropogenic activities have exerted increasingly large-scale influences on terrestrial ecological systems from the past century, primarily through agriculture; however, the impact of such changes on the hydrologic cycle is poorly understood. As one of the important land use (LU) in the coastal Dogo Plain of the Seto Inland Sea, Japan, paddy fields have been decreasing with the increase in urbanization in recent decades. As the main source of water in the Dogo Plain, groundwater plays an important role in providing people with fresh water and contributing to stream base flow. The purpose of this study is to analyze the water resource and evaluate the effect of LU change on groundwater table fluctuation in this coastal plain. Firstly, the observations of groundwater table and the investigation of water balance were carried out in this alluvial plain. Then, a distributed four-block three-layer water balance model was employed to analyze the groundwater table fluctuation with response to the change of paddy field area. Moreover, the role of paddy field in recharging groundwater in the basin has been clarified. Results show that groundwater table depends not only on rainfall and discharge from rivers, but also on irrigation water and topology of the study area. The net groundwater recharge was positive in irrigation periods whereas that in non-irrigation periods was nearly equal to zero or negative. The results of this study would be helpful to the urban development policy and land use planning decision.     

Management of Alluvial Aquifers in Two Southern African Ephemeral Rivers: Implications for IWRM

This paper summarises innovative research into the assessment of long-term groundwater recharge from flood events in dryland environments of the Kuiseb (Namibia) and the Buffels (South Africa) rivers. The integrated water resource management (IWRM) policies and institutions affecting the exploitation of groundwater resources in each of these developing countries are compared. The relatively large alluvial aquifer of the Kuiseb River (～240 Mm³) is recharged from irregular floods originating in the upper catchment. Reported abstraction of 4.6 Mm³ per year is primarily consumed in the town of Walvis Bay, although the groundwater decay (pumping and natural losses along the period 1983–2005) was estimated in 14.8 Mm³ per year. Recharge is variable, occurring in 11 out of 13 years in the middle Kuiseb River, but only in 11 out of 28 years in the middle-lower reaches. In contrast, the Buffels River has relatively minor alluvial aquifers (～11 Mm³) and recharge sources derive from both lateral subsurface flow and floodwater infiltration, the latter limited to a recharge maximum of 1.3 Mm³ during floods occurring once every four years. Current abstractions to supply the adjacent rural population and a few small-scale, irrigated commercial farms are 0.15 Mm³ yr^???1, well within the long-term sustainable yield estimated to be 0.7 Mm³ yr^???1. Since independence in 1990, Namibia’s water resource management approach has focussed on ephemeral river basin management of which the Kuiseb Basin Management Committee (KBMC) is a model. Here, some water points are managed independently by rural communities through committees while the national bulk water supplier provides for Walvis Bay Municipality from the lower aquifers. This provides a sense of local ownership through local participation between government, NGOs and CBOs (community-based organisations) in the planning and implementation of IWRM. Despite the potential for water resource development in the lower Buffels River, the scope for implementing IWRM is limited not only by the small aquifer size, but also because basin management in South Africa is considered only in the context of perennial rivers. Since 2001, water service delivery in the Buffels River catchment has become the responsibility of two newly created local municipalities. As municipal government gains experience, skills and capacity, its ability to respond to local needs related to water service delivery will be accomplished through local participation in the design and implementation of annual ‘integrated development plans’. These two case studies demonstrate that a variety of IWRM strategies in the drylands of developing countries are appropriate depending on scales of governance, evolving policy frameworks, scales of need and limitations inherent in the hydrological processes of groundwater resources.     

江苏南通部分地区深层地下水咸化成因及对策

为了解江苏南通部分地区深层地下水水质咸化的状况及产生原因,对全市深层地下水的3个开采阶段进行了初步分析。找出了导致该地区深层地下水咸化的原因为：多年高强度开采、隔水层薄弱地区的越流补给、不规范的成井工艺等改变了深层地下水的正常流动与补给。根据研究结果,提出了加强开采管理、根据水文地质条件科学布井、强化取水许可全过程监管、全面回填报废管井等综合应对措施。     

西辽河流域平原区地下水动态补给研究

基于分布式水循环模拟模型MODCYCLE,建立强人类活动影响下西辽河流域水循环模拟模型,量化西辽河平原地下水补给组成,分析地下水动态补给情况及年际、年内变化。分析结果表明：西辽河流域平原区地下水补给以降水入渗补给为主,与年降水量直接相关。随降水减少,降水入渗补给比重减少,河道入渗补给及灌溉回归补给比重增加。地下水补给的年内变化差异较大,且与年内降水分布直接相关。研究结果可为西辽河平原地下水资源可持续开发利用提供依据     

保定市一亩泉地下水回灌水文地质条件分析

通过对区域水文地质条件、现场回灌试验等资料的综合分析,对保定市一亩泉水源地下水超采降落漏斗分布范围、地下储水空间、回灌水向深层含水层及外流域流失的可能性,及入渗场地下水回灌地质条件等进行了系统分析,在此基础上选择了适于本区水文地质条件的地下水回灌方法。     

用于裂隙岩溶含水层回灌的屋面雨水径流水质特性研究

本文以北方地区裂隙岩溶水典型城市济南市为研究区，监测分析了2008年2月至8月降水过程的降雨量、降雨强度，同时对研究区13次天然降水的11项指标与位于裂隙岩溶水直接补给区7次降水形成的屋面径流的28项指标进行检测，识别出屋面径流主要污染物类型，探讨了2008年春季和夏季各次降雨形成的屋面径流中不同污染物随降雨历时、降雨强度和季节的变化规律；分析了径流污染物的来源，并对屋面径流雨水通过井回灌裂隙岩溶含水层用于饮用水的处理方法及效果进行了探讨。济南市屋面水质的研究为济南城市屋面雨水回灌裂隙岩溶含水层提供了依据。     

建筑屋面雨水有压回补地下水理念与潜力评估

城市雨水回补地下水对增加城市地下水资源、减轻内涝灾害具有重大意义。屋面雨水水质较好,且具有高水头特点,并无需外界提供电能、不占据多余空间,可实现雨水收集、快速净化,形成屋面雨水有压回补地下水模式,增加地下水回补率。该技术理念提出后,尚处于研究阶段,故本文以天津大学新校区为研究区,通过水泵加压回补地下水的现场数据推导出了半经验公式,选取与实地状况基本相符的渗透率等相关参数,对该模式进行相关计算与潜力评估。利用天津市暴雨公式计算了不同降雨重现年及历时的设计雨强,并计算出本模式应用于研究区的不同设计情况下的回补率。计算结果显示,回补率与降雨历时(建筑屋面汇水或滞留时间)呈正相关关系;假设建筑屋面雨水滞留时间为24 h时,25年一遇以内降雨回补率大于90%,50年一遇和100年一遇降雨回补率达85%以上。本文论证了该种模式具有很强的应用价值,对雨水回补地下水技术研究有一定的参考价值。     

Groundwater Recharge Assessment for the Kalahari Catchment of North-eastern Namibia and North-western Botswana with a Regional-scale Water Balance Model

Groundwater is the only source of drinking water for the inhabitants of the Kalahari. Thus understanding spatial and temporal variations in groundwater recharge is very important and a regional-scale water balance model has therefore been set up for a 209,149 km² catchment in north-eastern Namibia and north-western Botswana. The model has a spatial resolution of 1.5 × 1.5 km, daily model time-steps, and climatic input parameters for 19 years are used. The distributed, GIS-based, process-oriented, physical water balance model (MODBIL) used in this study considers the major water balance components: precipitation, evapotranspiration, groundwater recharge, and surface runoff/interflow. Mean precipitation for the study area is 409 mm a⁻¹, while mean actual evapotranspiration is 402 mm a⁻¹ and mean groundwater recharge is 8 mm a⁻¹ (2% of mean annual precipitation). The recharge pattern is mainly influenced by the distribution of soil and vegetation units. Groundwater recharge shows a high inter- and intra-annual variability, but not only the sum of annual precipitation is important for the development of groundwater recharge; a large amount of precipitation in a relatively short period is more important. Published independent data from the Kalahari in Namibia, Botswana and the Southern African region under similar climatic conditions are used to verify the modelling results.     

An Analytical Solution of Boussinesq Equation to Predict Water Table Fluctuations Due to Time Varying Recharge and Withdrawal from Multiple Basins, Wells and Leakage Sites

Recharging and pumping are the integral part of any scheme of ground water resources development and both processes significantly affect the dynamic behavior of the aquifer system. Leakage from the aquifer’s base, if present, is other process which affects the water table variation. Therefore, an accurate estimation of water table fluctuation induced by recharging, pumping and leakage is pre-requisite to ensure sustainability of groundwater resources. In the present work an analytical solution of a 2-D linearized Boussinesq equation is developed to predict water table fluctuations in the presence of time varying recharge, pumping and leakage from any number of recharge basins, wells and leakage sites of any dimension for any number of recharge and pumping cycles. The rate of time varying recharge (or pumping) is approximated by using a series of linear elements of different lengths and slopes which are dependent on the nature of variation in the recharge (or pumping) rate. Application of the solution in the prediction of water table fluctuation in the presence of time varying recharge, pumping and leakage is demonstrated with the help of a numerical example. These numerical results indicate significant effect of the time varying recharge/pumping rates and leakage on the water table variation. Such information is useful for the proper management of groundwater.