Management of Groundwater Resources in Eastern Saudi Arabia

Effective management of groundwater in arid countries, such as Saudi Arabia, is an important factor in sustainable development. A regional numerical simulation model of a multi-aquifer system including the Dammam and Umm Er Radhuma (UER) aquifers was developed to assess the behaviour of the aquifer system under long-term water stresses. The model was utilized to predict the responses of the aquifer system under three alternative pumping schemes over a planning horizon of 31 years (1995-2025). Model results postulate that dewatering of the Dammam aquifer will occur at low productivity sites and along the outcrop with the current trend towards increasing abstraction. The UER will exhibit significant cones of depression at large irrigation projects. Aquifer dewatering and drawdowns will be minimal with the conservation alternative. This management scheme should be adopted for the future development and protection of groundwater in the province.     

Effect of management strategies on reducing negative impacts of climate change on water resources of the Isfahan–Borkhar aquifer using MODFLOW

Recently, many studies have investigated the effect of climate change on groundwater resources in semiarid and arid areas and have shown adverse effects on groundwater recharge and water level. However, only a few studies have shown suitable strategies for reducing these adverse effects. In this study, climate conditions were predicted for the future period of 2020–2044, under the emission scenarios of RCP2.6, RCP4.5, and RCP8.5, for Isfahan–Borkhar aquifer, Isfahan, Iran, using MODFLOW‐2000 (MODFLOW is United States Geological Survey product). Results showed that the average groundwater level of the aquifer would decrease to 13, 15, and 16 m in 2012 to 2044 approximately under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. Then, three groundwater sustainability management scenarios were defined that included 10%, 30%, and 50% reduction in groundwater extraction. These strategies simulated the reduced negative effects of climate change on the aquifer. The results showed that decreases in water withdrawal rates of 10%, 30%, and 50% under RCP8.5 scenario (critical scenario) could decrease the mean groundwater level by 14, 11, and 7 m, respectively. The main result of the study showed that 50% reduction in groundwater withdrawal may increase the groundwater levels significantly in order to restore the aquifer sustainability in the study area. In this study, with assuming that the current harvest of wells in the future period is constant, so the results of studies showed that for the aquifer's sustainability management, the water abstraction from the aquifer should reduce up to 50% of the existing wells. Changing the irrigation method from surface to subdroplet irrigation plays an important role in reducing the withdrawal from the aquifer. The results of a study in Iran have shown that the change in the irrigation method from surface to subdroplet irrigation causes a 40% reduction in water use for agriculture.     

Multiobjective management of a contaminated aquifer for agricultural use

Planned utilization of groundwater from a contaminated aquifer requires development of management strategies that determine the spatial distribution of withdrawal for allocation, as well as for control of water quality. Minimization of groundwater allocation for different purposes, and the control of contamination in the aquifer by a specified pumping strategy constitute a management problem with two conflicting objectives. In order to demonstrate possible tradeoffs between water quality control objective and minimum groundwater withdrawal objective, a multiobjective optimization model is formulated. The solution of the model specifies a strategy to control pollution distribution in the aquifer as per agricultural needs, and also evolve an optimal allocation policy to statisfy agricultural demands. Pareto-optimal solutions representing the tradeoff between the two noncommensurate objectives are established. The formulated model uses the embedding technique for simulating the flow and the transport processes in the aquifer. The constraint method is used to transform the multiobjective optimization model into a single objective optimization model. The resulting model is solved using the exterior penalty function method in conjunction with the Hooke-Jeeves method. The proposed model is easily adoptable for various agroclimatic regions and cropping patterns. For illustrative purposes, the model is applied to a specified study area. Although solutions of the model are presented and discussed as per agricultural requirements in terms of both quality and quantity, solutions for other kinds of water demands can be obtained using the same model with minor modifications. Results show that an optimal pumping strategy can be effectively utilized for controlling contamination in the aquifer.     

Evaluation of Groundwater Resources in Lower Cretaceous Aquifer System in Sinai

The Sinai Peninsula has an area of 61000 km² and its populationis about 325000. It is located in an arid area. Extensivedevelopment in the socio-economic, industrial and agriculturalis in process. Although Lower Cretaceous aquifer is the mostprospective aquifer in Sinai, it is not yet precisely evaluated.Spatially distributed areas of good groundwater quality suitablefor various types of development are not identified.The current article presents a comprehensive assessment of thehydrogeological information and hydrological data. Accordingly,three aquifer zones have been identified. Groundwater reserve wasestimated and groundwater balance has been developed. Developmentpotential was evaluated. Development criteria were proposed and applied.Suitable areas for domestic and irrigation purposes weredelineated. Results indicated that the aquifer contains 308 billion m³ ofgroundwater of which a considerable volume is of good quality. Bylowering the present water level some 200 meters, the aquiferyielded 3643 million m³, which is sufficient to supply thepresent rate of withdrawal for 445 years. The results are considered to be usefulfor preparing groundwater master plans in Sinai. Under the properwater management, Sinai could be self sufficient in satisfying itsdomestic water demand.     

地下水位下降对干旱区膜下滴灌棉花需水量的影响

膜下滴灌种植方式大面积在西北干旱地区推广应用,使得该区地下水得不到有效补给,地下水位出现大幅下降。水位下降使地下水对土壤水的顶托作用和潜水的蒸发作用减弱,对作物需水量产生一定影响。利用2008~2018年新疆巴音郭楞蒙古自治州国家重点灌溉试验站不同地下水位进行滴灌实验的有利条件,研究地下水位下降对干旱地区膜下滴灌棉花滴灌水量的影响,并使用Penman-Monteith公式计算地下水埋深7～8 m时膜下滴灌棉花的需水量。研究表明：地下水位下降致使干旱地区的膜下滴灌棉花高产的需水量上升;滴灌水的入渗能力具有随矿化度增加而增加的趋势,且适宜的含盐量对棉花的生长具有一定的协同作用;当地下水埋深大于6 m时,水位的进一步下降将不再促使膜下棉花的需水量进一步上升。     

马鞍山市地下水水源地应急供水水流模拟研究

为评估马鞍山市应急水源地的供水能力,结合现场水文地质勘察成果,概化了区域水文地质模型,采用GMS软件进行应急开采条件下的地下水渗流场模拟预测。计划布置抽水井75口,模型预测了总开采量15万m^3/d时区域地下水流场的时空分布特征。计算结果表明各水源地应急开采过程中,水源地周围降落漏斗中心降深逐渐增大,胡庄和秦河村水源地由于含水层相对较薄,远离区域主要的补给水源(长江),供水能力较差,降落漏斗中心埋深最大;新锦村靠近长江,抽水井数量相对较少,降落漏斗中心埋深最小。经过365 d抽水,区域降落漏斗最大降深达4.61 m,降落漏斗最大半径达3 000 m。马鞍市拟选应急水源地的供水能力可以达到15万m^3/d,但是水源地应布置在含水层厚度大,补给可靠的区域。     

Quantitative Assessment of Regional Rock Aquifers, South-Western Quebec, Canada

The population of the St. Lawrence Lowlands platform in south-western Quebec, Canada, is heavily dependent on groundwater. The present study summarizes the quantity, quality and sustainability estimations of the groundwater resources found mainly in sedimentary rock aquifers. Results show that the regional groundwater flow in the considered domain of 1,500 km² is 97.7 Mm³/y with: 86.6% infiltration from precipitation, 9.6% inflow from neighboring aquifers, and 3.8% induced recharge. The regional sustainability is defined with simulated drawdowns from uniform withdrawal scenarios. The current withdrawal rate of 18 Mm³/y results in median drawdown of 0.6 m, compared to pre-development conditions. This drawdown is situated well in the sustainable range, an indication that regional aquifers are not overexploited. Hypothetical pumping rate of 24 Mm³/y resulting in an average drawdown of 2.2 m is estimated as sustainable limit. Increasing exploitation from 24 to 51 Mm³/y would need tight control and planning. Pumping rates beyond 51 Mm³/y are judged not sustainable as regional drawdowns become high, ∼8 m. The water levels in recharge areas are the most sensitive to groundwater extraction. Combining drawdown maps, groundwater quality zones, and aquifer vulnerability to surface contamination delineated the areas most suitable for future groundwater developments.     

变化环境对华北平原地下水可持续利用的影响研究

针对华北平原地下水利用中存在的问题,采用分布式水文MIKE SHE模型,考虑人类活动（农业节水措施和南水北调工程）和气候变化等变化环境的影响,通过设定4大类情景（每类情景中均设定了3类气候变化子情景）模拟了2019-2028年华北平原地下水的利用状况。结果表明：农业节水措施和南水北调工程等人类活动对华北平原地下水水位、水均衡和含水层储量有较大的影响;相对于现状保持型情景(SQM),模拟期末(2028年12月31日)农业节水型情景(AWS)、南水北调工程供水型情景(SNWDP)和综合利用型情景(CU)下华北平原饱和含水层储量分别增加0.168、0.558和1.433 m;气候变化对华北平原地下水的影响量级与人类活动的影响相当,且地下水水位、水均衡和含水层储量变化的方向和大小均与未来气候条件的干湿程度呈正相关关系,到模拟期末,相对于现状保持型情景(SQM),湿润、正常和干旱的气候情景下华北平原饱和含水层储量分别为增加0.972~2.239 m、增加0.119~1.540 m和减少0.372~0.940 m;只有综合考虑各种引水和节水措施,多管齐下,才能保证华北平原地下水的可持续利用。     

GIS-Based Groundwater Management Model for Western Nile Delta

The limited availability of renewable fresh water is a major constraint on future agriculture and urban development in Egypt. The main water resource that Egypt has been depending on is the River Nile. Nowadays, the role of groundwater is steadily increasing and will cover 20% of the total water supply in the coming decades especially in the reclaimed areas along the desert fringes of the Nile Delta and Valley. Abstraction from groundwater in Egypt is dynamic in nature as it grows rapidly with the expansion of irrigation activities, industrialization, and urbanization. One of these areas is the Western Nile Delta in which the groundwater is exploited in many localities. To avoid the deterioration of the aquifer system in this area, an efficient integrated and sustainable management plan for groundwater resources is needed. Efficient integrated and sustainable management of water resources relies on a comprehensive database that represents the characteristics of the aquifer system and modeling tools to achieve the impacts of decision alternatives. In this paper, a GIS-based model has been developed for the aquifer system of the Western Nile Delta. The GIS provides the utilization of analytical tools and visualization capabilities for pre-and post-processing information involved in groundwater modeling for the study area. The developed model was calibrated for steady state and transient conditions against the historical groundwater heads observed during the last 20 yr. The calibrated model was used to evaluate groundwater potentiality and to test two alternative management scenarios for conserving the aquifer system in Western Nile Delta. In the first scenario, reducing the surface water inflow while increasing the annual abstraction from groundwater by about 450 million m³ and improving the irrigation system could increase the net aquifer recharge by about 5.7% and reduce the aquifer potentiality by about 91%. Constructing a new canal as a second management scenario could increase the annual aquifer potentiality by about 23%. The GIS-based model has been proven to be an efficient tool for formulating integrated and sustainable management plan.     

河南省浅层地下水动态演变分析

20世纪80年代以来,河南省地下水开采量持续增加,导致地下水补排关系失衡,地下水位持续下降,其中:海河流域平原水位下降了7.25 m,下降速率为0.24 m/a;黄河流域下降了3.14 m,下降速率为0.10 m/a;淮河流域与长江流域地下水位基本保持稳定。1980—2010年河南省平原区地下水位下降了1.65 m,地下水蓄变量减小了51.5亿m3,其中海河流域与黄河流域蓄变量大幅减小,部分含水层已疏干。     

变化环境下地下水埋深动态特征及驱动因素分析

随全球气候变化和人类活动加剧,地下水循环系统发生着深刻的演变,研究变化环境下地下水埋深动态特征具有重要意义。从变化环境与地下水循环系统相互作用关系出发,利用乾安县2000—2015年地下水监测井水位埋深数据、气温、降水量、蒸发量及人工开采量、土地利用等资料,通过Mann-Kendall趋势检验、灰色关联度分析及衬度系数方差分析得出变化环境下研究区地下水动态特征:气候变化和人类活动是影响地下水埋深的主要因素; 16年来,研究区承压水位埋深显著增大,潜水埋深变化不显著;气候变化和人类活动分别是研究区潜水和承压水水位埋深动态的主要外在驱动因素,含水层自身厚度是控制承压水位埋深动态响应程度的内在因素,同时提出变化环境下干旱半干旱平原区地下水埋深响应机制。     

Hydric Restoration of the Agua Amarga Salt Marsh (SE Spain) Affected by Abstraction from the Underlying Coastal Aquifer

The Agua Amarga coastal aquifer, located in the southeast of Spain (Alicante province) has suffered a significant decrease in its piezometric levels due to its use to supply water to Alicante I and II desalination plants. In order to recover its natural levels and to preserve the salt marsh of ecological interest linked to the aquifer, whose origin is related to ancient saltworks, a pilot scheme based on depositing seawater over the salt marsh surface has been carried out from December 2009 to July 2010. As a result, piezometric levels have increased by around 2 and 3 m below the salt marsh and a general decrease in groundwater salinity of between 15 and 100 g/l has been measured. A flow-transport numerical model with SEAWAT is used to assess and evaluate the seawater depositing programme.     

东光县地下水压采效果及环境影响预测

运用Visual-MODFLOW软件建立东光县地下水流数值模型,对不同压采方案下地下水水位回升效果进行预测,并分析其环境影响。结果表明:仅压采深层地下水(方案1)时,承压含水层水位整体明显抬升,升幅为2.0~11.7 m,其中处于超采区的东光县城区升高幅度最大;同时压采浅层和深层地下水(方案2)时,承压含水层水位增幅在1.4~11.6 m,城区水位增幅依然最大。两种压采方案对潜水含水层的影响有限,潜水位前期出现不同程度的波动,后期水位较为平稳。总体上,两种方案下整个区域主要潜水位埋深为3~4 m;方案2下,个别地段水位埋深为1.8 m,低于本区防盐碱化临界水位埋深2.0 m,可能造成次生盐碱化风险。     

应用数值技术揭示开采地下水对河道径流量的影响

利用VisualMODFLOW软件,模拟河流基流的减少、河流入渗的增加两个过程在抽水期间和抽水后期的地下水位场变化,直观的揭示了开采地下水对河道径流量的影响.得出:开采是导致研究区下游地下径流排泄量呈现逐年减小的趋势.从整体水均衡来看,模拟区含水层2001年至2004年都处于负均衡状态,说明该区地下水已出现超采现象.     

Management perspectives on a deep aquifer system for rural water supply in Olt and Vàlcea counties, Romania

The water supply in the Romanian counties of Olt and Vàlcea is mainly from groundwater from a deep aquifer system in Pliocene formations. Isotope analyses have been used to establish the supply area of the deep aquifer system. The age of the groundwater has been estimated for two samples by using ¹⁴C analysis. A simplified numerical model for a north–south cross‐section has provided global values for the hydraulic conductivity and effective porosity of the aquifer system. The groundwater from permeable horizons deeper than 120–140 m is highly mineralised and is, therefore, inappropriate for use as a water supply. Because groundwater resources are limited, the water supply for industry and domestic use in urban regions cannot increase too much. Thus, the deep aquifer system could also be used as a water supply for rural regions.     

宿州市城西水源地地下水限采及其效果分析

针对宿州市城西水源地由于长期开采地下水、井位布局不合理,且地下水补给有限,已严重超采,形成了若干个地下水水位降落漏斗,直接威胁城区供水安全的现实,通过数值模拟法计算宿州市城西水源地的地下水可开采量,采用开采系数法对水源地进行地下水超采评价,并制定相应的限采方案,预测限采后地下水水位的变化,分析限采效果。结果表明,现状年2010年城西水源地地下水开采系数为1.30,属于严重超采;实施限采方案后,规划年2015年、2020年,地下水开采系数分别为1.21、0.97,限采效果较明显。     

Post Audit Analysis of a Groundwater Level Prediction Model in Developed Semiconfined Aquifer System

This paper assesses groundwater recharge under conditions of long-term groundwater pumping at the Ravnik pumping site in Croatia and analyses the groundwater level prediction model used in prior aquifer modelling. The results of model calibration revealed a very low net infiltration rate at the start of the pumping site’s operation. As the operation continued, the net infiltration rate slowly increased, while the percentage of infiltrated rainfall scaled up with increasing pumping rates. The predicted recharge of the covering aquitard amounts approximately 14–15 % of the mean annual precipitation. The aquifer recharge takes place from aquitard by seepage. A subsequent simulation of the pumping site’s operation was performed for the 9 years period on the assumption that the pumping rates and the groundwater recharge would be the same as those recorded during the final calibration years. Results show that the post audit measured levels correspond relatively well to the predicted levels and that increasing of the pumping rate causes changes in the water budget in advantage of net groundwater recharge as a consequence of spreading recharge area outside of previous model boundaries.     

Effect of New Nag Hammadi Barrage on Groundwater and Drainage Conditions and Suggestion of Mitigation Measures

The government of Egypt has decided to construct a new barrage with hydropower facilities, 3.5 km downstream of the existing old one. The water levels in the head pond for the new barrage will be continuously maintained at a level with approximately 0.5 m higher than water level in the head pond of the existing one. To evaluate the effect of increasing the head pond water level on the groundwater and drainage, there is a need to enhancelinking reservoir and stream/aquifer system. Visual MODFLOW hasbeen used to simulate the surface water/groundwater interaction in the area of proposed new barrage. The model has been calibratedagainst the available historical groundwater levels for 25 observation wells based on the steady state conditions. Numerical modeling suggests that river stage is the primary control of rapid groundwater hydraulic head fluctuations in theaquifer system. At present the area at which the depth to groundwater table less than one meter is about 30 110 feddans (1 feddan = 4200 m²). This area will increase to be about40 610 feddans after the construction of the new barrage and increasing the head pond water level. The mitigation measures toovercome the effect of construction of the new barrage have been discussed and their costs have been estimated and evaluated. Increasing the efficiency of existing drainage system by maintenance/upgrading and constructing a new pump station is recommended.     

Regional management modeling of a complex groundwater system for land subsidence control

The three-dimensional groundwater flow model MODFLOW and the one-dimensional consolidation model are coupled and calibrated to simulate the piezometric levels and land subsidence in the complex multi-aquifer system of the lower Central Plain of Thailand. The mathematical models are calibrated against historical data for the period 1955–1990 by considerably updating the system conditions used by previous studies. The aquifer system responses to different pumping schemes are then predicted for the period 1991–2010. The modeling procedure is carried out in close consultation with the Department of Mineral Resources (DMR), Royal Thai Government. The conclusions of the study will allow the DMR to develop and implement updated groundwater management policies, land subsidence control strategies and action programs in the Bangkok Metropolitan Area.     

Response Matrix Minimization Used in Groundwater Management with Mathematical Programming: A Case Study in a Transboundary Aquifer in Northern Greece

Groundwater has always been considered to be a readily available source of water for domestic, agricultural and industrial use. The last decades, the lack of policymaking for the utilization of groundwater, has led to overexploitation in many areas. The cooperation of a wide range of scientists such as mathematicians, engineers, computer scientists, environmentalists and economists – operation researchers, have led to the design and construction of commercial computer programs concerned on water management and specifically on the optimal distribution of limited water resources using groundwater management models. These combined models, via simulation and optimization algorithms, result in one optimal solution through operations research and mathematical programming methods. The groundwater management models are based on the method of space superposition or the combination of space and time superposition for steady and unsteady state problems, respectively. In the present study, an algorithm is presented, which minimizes the dimension of the response matrix, concerning on two assumptions: the first is the added fixed cost which represents the water supply pumping well and the second is the removal of time superposition. The study area is a transboundary phreatic aquifer in Northern Greece, in the area of Eidomeni, a small Hellenic village just on the borderline with FYROM. The aquifer has a total area of 10,84 km², 26 operating – pumping wells, which the 9 of them consist control points of the hydraulic head. The number of the management periods is 12 months.