Groundwater Exploration and Assessment in Rural Communities of Yobe State, Northern Nigeria

The provision of adequate water supply and sanitation to the rapidly growing urban populations is increasingly becoming a problem for governments throughout the world. The continuing expansion of the numbers of people in cities who need water and sanitation services form a continuous pressure to either invest in additional production capacity or to stretch the available supplies to serve more people. Due to rapid increase in population growth in the Yobe State north of Nigeria, there is a shortage in the water supply to Damaturu city the capital of the state and surrounding villages. At the present the total water supply is about 10,000 m³/day abstracted form the shallow alluvial groundwater aquifer using 29 production wells. Due to the expected increase in water demand and the limited potentiality of shallow aquifer system, other deep aquifers were explored and investigated to evaluate their potentiality for future water demand. Vertical Electrical Sounding Method was used for the geophysical survey of the study area. Groundwater flow model was developed and calibrated against the historical information. Three wellfields were designed to provide Damaturu city and surrounding villages with the required water. The calibrated model has been used to evaluate the aquifer potentiality and the effect of future withdrawals on the deep aquifer system. It was found that the aquifer system within the study area consists of two main layers. The upper layer is the Chad formation comprises an alluvial sand and gravel with intercalation of thin sility clay layers. The second layer is Keri-Keri formation consists of sandstone formation which is not explored before. During this study the Kerri-Kerri aquifer system was investigated as an alternative source for groundwater for future demand. The study presents an integrated groundwater resources management strategy for present and future water supply for rural communities.     

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.     

Variation and Trends in Agricultural Drainage Water Reuse in Egypt

ABSTRACT

A substantial quantity of agricultural drainage water flows annually from the Nile Delta to the Mediterranean Sea and North Lakes. The volume and salinity of this water vary both with time and space. Policies for developing water resources in Egypt and maximizing its use include the reuse of agricultural drainage water for irrigation. This implies that water of lower quality than the Nile water will be used in irrigation. The reuse of this water as a reliable resource is limited by its quality, which in turn determines the quantity that can be used.

During the past decade Egypt started an ambitious program towards the goal of achieving higher water use efficiency to face the increasing water demands. The future improvement of the irrigation system, the better allocation of available water resources and the efficient utilization of irrigation water will affect the quantity and quality of agricultural drainage water: The start of this program was associated with a sharp decrease in the natural flow of the River Nile. The prevailing operational and management conditions had decreased the irrigation and drainage discharges and increased the salinity of drainage water

In this paper the historical discharge and salinity data about the drainage water in the Nile Delta will be analyzed to determine the trends and tendencies of their changes. The effect of management of Nile water releases from the High Aswan Dam on drainage water quantities and qualities is discussed. This study is carried out on a regional scale, covering the east, the middle and the west parts of the Delta.     

Simulation supported scenario analysis for water resources planning: a case study in northern Italy.

The work presents the results of a comprehensive modelling study of surface and groundwater resources in the Muzza-Bassa Lodigiana irrigation district, in Northern Italy. It assesses the impact of changes in land use and irrigation water availability on the distribution of crop water consumption in space and time, as well as on the groundwater resources. A distributed, integrated surface water-groundwater simulation system was implemented and applied to the study area. The system is based on the coupling of a conceptual vadose zone model with the groundwater model MODFLOW. To assess the impact of land use and irrigation water availability on water deficit for crops as well as on groundwater system in the area, a number of management scenarios were identified and compared with a base scenario, reflecting the present conditions. Changes in land use may alter significantly both total crop water requirement and aquifer recharge. Water supply is sufficient to meet demand under present conditions and, from the crop water use viewpoint, a reduction of water availability has a positive effect on the overall irrigation system efficiency; however, evapotranspiration deficit increases, concentrated in July and August, when it may be critical for maize crops.     

灌区地表水—地下水耦合模型的构建

为了定量描述灌区水平衡要素及其转化关系,构建了灌区地表水-地下水分布式模拟耦合模型。通过改进SWAT模型的稻田及旱作物水分循环、蒸发蒸腾量和渠系渗漏计算等模块,建立了灌区地表水分布式模拟模型;以SWAT模型中的水文响应单元(HRU)和MODFLOW模型中的有限差分网格(cells)作为基本交换单元,将改进SWAT模型的地下水补给量计算值加载到MODFLOW模型的地下水补给模块,实现了灌区地表水-地下水分布式模拟模型的耦合。耦合模型在柳园口灌区的应用结果表明,该模型能够准确模拟和预测灌区地表水和地下水的动态变化,为灌区水管理提供了科学依据。     

地下水功能区划分浅谈

简要介绍了我国地下水面临的主要问题:资源枯竭、生态功能退化、环境地质灾害加剧。根据地下水系统具有的资源供给、生态环境保护、地质安全保障这三大功能,分析了地下水功能与当前地下水面临的诸多问题的关系,提出将地下水分布区划分成四类一级功能区,即开发利用区、生态环境保护区、地质灾害防治区和保留区,分析了地下水功能区和地下水超采区的关系,建议将地下水功能区和地表水功能区联合起来,构成水资源统一管理的技术平台。指出地下水保护的程序是:进行地下水功能区划,建立地下水功能区评价指标体系,研究地下水保护的标准体系,制定和实施地下水系统保护方案,加强地下水监测和管理。     

Predictive Simulation of Flow and Solute Transport for Managing the Salalah Coastal Aquifer, Oman

A three-dimensional numerical model for flow and solute transport was used for the management of the Salalah aquifer. The model calibration procedures consisted of calibrating the aquifer system hydraulic parameters by history matching under steady and transient conditions. The history of input and output of the aquifer were reconstructed in a transient calibration from 1993 to 2005. Predictive simulation of the aquifer was carried out under transient conditions to predict the future demand of groundwater supply for the next 15 years. A baseline scenario was worked out to obtain the piezometric surface and salinity distribution for the “business as usual” conditions of the aquifer. The “business as usual” scenario was predicted and simulated for the period 2006 until 2020. The effectiveness of seven management options was proposed and assessed for comparison with the “business as usual” conditions. The established simulation model was used to predict the distribution of the piezometric surface, salinity distribution, and mass balance under the proposed scenarios for the prediction period 2006–2020. The scenarios were: (1) relocate Garziz and MAF farms far from the freshwater zone, (2) suspend the abstraction of grass production for 4 months a year, (3) changes in agricultural and irrigation system patterns, (4) establish a desalination plant, (5) combined scenario (1 + 4), (6) combined scenario (1 + 3), and (7) combining all scenarios (1 + 2 + 3 + 4). The result of the simulation shows that the best effective option in terms of aquifer groundwater levels is the fifth proposed scenario and the sixth proposed scenario is the best effective option in terms of aquifer groundwater salinity situation during the next 15 years. This project suggested the application of scenario 6 as it is environmentally sound in terms of sustainable management. A prediction has been made which shows that further actions have to be taken within the next two decades to ensure continuity of the municipal water supply. The management scenarios are examined in the case of the Salalah coastal aquifer using groundwater simulation, which can also be applied to other regions with similar conditions. The established model is considered a reasonable representation of the physical conditions of the Salalah plain aquifer, and can be used as a tool by the water and environmental authorities in the management of the groundwater in the region.     

Future groundwater conditions under long-term water stresses in an arid urban area

The urban area of Greater Dhahran has an extremely arid climate where the average annual rainfail is less than 71 mm. The Umm Er Radhuma (UER) aquifer in that area is the main source of domestic and landscape irrigation demands. Groudwater use has increased drastically during the last 15 years due to extensive developments in the area. Numerical simulation techiques and hydrogeochemical investigations were carried out to assess the effects of increasing pumping rates on the piezometric surface in the UER aquifer and to predict the future levels and quality of water under different pumping scenarios. A groundwater flow model was developed and calibrated for the area. The increase in the water extraction rate between 1967 and 1990 has resulted in a decline in the piezometric surface by about 4 m in the Dhahran area. The results of simulation investigations indicated that if the present trend of the groundwater withdrawal rate continues, the water level is expected to drop by an additional 2 and by the end of the year 2000, by an additional 6 m by the end of 2010. If the present increasing rate in groundwater withdrawal is reduced by 50%, the additional drawdown will also be reduced to about 1 and 2.5 m by the end of years 2000 and 2010, respectively. The average total dissolved solids (TDS) has increased from 2750 to 3545 mg/l between 1967 and 1990 and will continue to rise to 3922 and 4361 by the end of years 2000 and 2010, respectively. These original findings are important because they postulates the negative impacts of increasing groundwater pumping from an aquifer in an arid urban area on future groundwater levels and quality. Therefore, effective groundwater management and conservation schemes should be adopted to maintain the long-term productivity and quality of aquifers in the area.     

陡河流域地表水与地下水转化关系

通过对陡河流域地表水-地下水水样的氢氧同位素分布特征进行分析,发现研究区河岸带第Ⅰ含水层除了受大气降水、灌溉回归水入渗补给外,还接受河水早期的渗漏补给,第Ⅱ含水层对第Ⅲ含水层有越流补给,第Ⅱ含水层同时也受大气降水和灌溉回归水的影响,而远离河岸带的第Ⅳ含水层与上覆各含水层稳定同位素组成显著不同,河岸带水库附近的第Ⅳ含水层可能受地表水库渗漏影响。河岸带地下水与地表水水力联系的变迁严格受河岸带地下水水位变化控制,如景庄子剖面的地下水埋深为5m,雨季时河水补给地下水,旱季时地下水补给河水,而靠近地下水漏斗中心的越河乡剖面地下水水位埋深达25m,其常年受地表水补给。     

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.     

干旱区微咸水灌溉对地下水环境影响的研究

本研究利用MODFLOW模型和MT3DMS模型对内蒙河套地区的一个灌区微咸水灌溉条件下的地下水位、水量、水质和含盐量进行了系统的模拟分析。结果表明,在抽取地下水灌溉后地下水位略有下降,10年后水位降深量仅为0.057～0.11m,可达到动态平衡。两种灌溉水平下,含水层盐分有增加趋势,但增加幅度较小,在4％～9％之间。采用微咸水灌溉,淋洗灌溉定额比正常灌溉定额的方案对环境有利,虽然淋洗灌溉定额也使含水层盐分增加,但就增加的幅度看,在未来相当一段时间内不会造成严重的环境问题。     

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.     

Groundwater Flow Modeling of the Arlington Basin to Evaluate Management Strategies for Expansion of the Arlington Desalter Water Production

Water supply reliability in Southern California is facing serious problems because of reduction in the availability of water from the State Water Project and Colorado River, drought, and growing concerns about environmental restoration. Groundwater sources supply more than fifty-five percent of domestic demands in the Western Riverside County. Western Municipal Water District is planning to increase water supply reliability by expanding the Arlington Desalter production which requires additional groundwater pumping from the Arlington Basin. Western was concerned that increasing groundwater pumping will cause excessive decline in groundwater levels, leading to decreased yields at existing Desalter wells. Three-dimensional groundwater flow model was developed for the Arlington Basin to investigate different water management strategies. Five groundwater management scenarios were run for a 30-year time period. The five model runs were used to determine the feasibility of the Arlington aquifer system to supply groundwater to the Arlington Desalter over the 30-year life of the facility. Model simulation results showed that long-term groundwater pumping from the existing Desalter wells is not sustainable without artificial recharge. However two of the modeling scenarios which incorporated a combination of artificial recharge and new production wells, were shown to meet the increased Desalter yield requirements as well as minimize adverse impacts.     

引黄灌溉对区域生态环境的影响及对策分析

引黄灌区在黄河三角洲地区农业和社会经济发展中具有特别重要的地位。但是,因为缺乏科学的用水管理体系,产生了很多不良影响,本文通过对小开河灌区的分析研究,得出引黄灌溉对区域生态环境的影响,即地下水位下降、地下水位升高和地下水污染。并对相应的影响提出对策分析以减小对生态环境的影响。     

Multi-Objective Optimization of Integrated Surface and Groundwater Resources Under the Clean Development Mechanism

Acquiring sustainable water resources for water-based development of countries is the experts? concern in this field, who seek to follow the clean development mechanism (CDM) regulations and overcome water crisis through integrated water resources management (IWRM). The Great Karun River basin is one of the major basins in the Middle East. This basin, containing six of the largest reservoir dams with a cumulative power plant capacity of more than 10,500 MW generates about 93% of hydropower of Iran. The water balance of the aquifer in the study area was simulated using MODFLOW model while water resources and surface water reserves were simulated by the water evaluation and planning (WEAP) model. A separate simulation was performed with each of two models and the results of two models were coupled using a link file. The multi-objective function optimization process including the maximized supply of demands and hydropower and the minimized aquifer drawdown was completed using non-dominated sorting genetic algorithm (NSGA-II). All effective system components, such as inter-basin water transfer, integrated use of water resources, variation of irrigation network efficiencies, and the effect of water shortage were studied and analyzed under the targeted scenarios. Finally, the best scenario, which was capable to supply the future needs until time horizon of 2040 was planned for the basin considering minimization of aquifer drawdown and optimal generation of hydropower resulting in a maximum decrease in emission of greenhouse gases.

     

宁南地区地下水系统划分方法研究

地下水系统的划分是正确评价宁南地区地下水资源的基础,以拥有独立的含水层系统和完整的水循环流动系统为原则,以构造控水理论为依据,将宁南地区地下水系统划分为9个一级地下水系统,19个二级地下水系统。地下水系统的划分有利于对当地地下水资源做出准确评价、开发、规划和管理。     

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...     

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.     

开采浅层水 增雨水入渗 引河水补源 水可持续用

南皮县淡水资源严重短缺,制约工农业与经济社会的发展。春季开采浅层地下水包括微咸水和半咸水抗旱灌溉,腾出地下含水层空间；汛期增加降雨入渗,减少径流流失,防渍防涝,把时空分布不均的天然降雨转化为地下水资源；秋冬利用河道沟渠引蓄河水补源,淡化地下水质,增加地下水可采量。地上水地下水联合运用,保持水资源采补平衡。实现旱涝碱咸综合治理、水资源可持续利用与经济社会可持续发展。     

水稻灌区基于多过程耦合的分布式水转化模型

水稻灌区灌溉-排水过程频繁,定量表征灌区水转化过程对于灌区水资源管理具有重要的意义。针对水稻灌区供-耗-排过程的时空复杂性以及灌区水转化对地下水补排过程的影响,本研究建立了灌区尺度基于灌排过程-农田土壤水分运动与作物生长过程-地下水运动过程耦合的分布式水转化模型,实现了对灌区的供-耗-排动态过程的定量表征。采用黑龙江省和平灌区水稻生长指标、灌区蒸散发量、地下水位变化以及排水沟流量等数据对模型进行了率定验证,结果表明模型具有较高精度。相对于传统灌区水转化模拟方法,该模型有效表征了灌区水转化所涉及的灌排过程、土壤水及地下水运动过程、作物生长过程的时空动态耦合,实现了灌区水转化的分布式动态模拟。同时,模型所需参数较少,避免了以往灌区水转化过程计算复杂的难点。该模型为水稻灌区多环节水转化过程模拟及用水效率评估提供了重要方法。