Estimation of groundwater recharge using the chloride mass-balance method, Pingtung Plain, Taiwan

 Due to rapid economic growth in the Pingtung Plain of Taiwan, the use of groundwater resources has changed dramatically. Over-pumping of the groundwater reservoir, which lowers hydraulic heads in the aquifers, is not only affecting the coastal area negatively but has serious consequences for agriculture throughout the plain. In order to determine the safe yield of the aquifer underlying the plain, a reliable estimate of groundwater recharge is desirable. In the present study, for the first time, the chloride mass-balance method is adopted to estimate groundwater recharge in the plain. Four sites in the central part were chosen to facilitate the estimations using the ion-chromatograph and Thiessen polygon-weighting methods. Based on the measured and calculated results, in all sites, including the mountain and river boundaries, recharge to the groundwater is probably 15% of the annual rainfall, excluding recharge from additional irrigation water. This information can improve the accuracy of future groundwater-simulation and management models in the plain. Received, April 1996 Revised, March 1997, November 1997 Accepted, March 1998     

黑河流域水资源转化特征及其变化规律

黑河流域水资源主要以冰雪水资源、 地表水资源与地下水资源的形式存在.上游祁连山区分布有现代冰川428条, 发育大小河流共计29条, 多年平均出山径流量37.83×10⁸m³·a^-1; 中下游走廊平原由松散沉积的第四系盆地组成, 接受出山河水及引灌河水的入渗补给, 是地表水资源的重复表现形式, 地下水补给量为25.637×10⁸m³·a^-1.受构造-地貌条件的制约, 自南部山区至北部盆地, 地下水与河水之间经过5个不同地带有规律的、 大数量的、 重复的转化过程, 形成完整统一的"山区地下水-出山地表水-中游盆地地下水-中游盆地地表水(泉水)-下游盆地地下水"水资源循环转化系统.     

Surface water and groundwater dynamic interaction models as guiding tools for optimal conjunctive water use policies in the central plain of Thailand

Many irrigation projects in the central plain of Thailand are not capable of providing sufficient surface water for the cultivation of rice, which is the major cash crop for Thai farmers. To overcome this surface water deficiency, which has been exacerbated in recent years by climate change, groundwater is increasingly being used for irrigation. Thus, large sections of agriculture lands have been converted to conjunctive water use regions. While conjunctive water use may be a suitable option to overcome the temporary water shortages on a short-term basis, it may pose a particular threat to the overall water resources in the long term, if not properly managed. As a remedy, conjunctive water management policies ought to be adopted. Conjunctive water management is basically a tool to optimize productivity, equity, and environmental sustainability through simultaneous management of surface water and groundwater resources. As of now, such a comprehensive approach has not been yet employed in the upper Chao Phraya basin of Thailand, and the present study is one of the first of this kind. The study region is the Plaichumpol Irrigation Project (PIP) where conjunctive water use has become indispensable for meeting the increasing water requirements for farming. To get a first grip on the issue, water demand, supply and actual use in the study area were investigated for the purpose of providing possible guidelines for optimal water exploitation. A numerical groundwater model with a special module for simulating surface-groundwater interaction was applied in the PIP area to understand the impact of the farmer’s irrigation behavior on the dominant hydrological processes that determine the seasonal and multi-annual water availability in the irrigation area. A set-up of different agricultural water allocation schemes that depend on the local weather conditions and the regional management rules are examined by the numerical models. The results of the simulations provide adaptation guidelines for the proper management of the conjunctive water resources, namely, optimal water utilization. The numerical results for the surface groundwater in particular indicated that while the irrigation canals recharge water to the aquifer during both dry and wet season, small amounts of discharge from the aquifers to the canals occur only during the wet season. The analysis of the groundwater balance also showed that the present available groundwater potential is not fully exploited by the farmers, especially during the dry periods of surface water shortage. In contrast, the adoption of an optimal conjunctive management scheme would ensure extra water availability for additional annual rice crops in the region.     

Impact of agricultural activity and lithology on groundwater quality in the Merdja area, Tebessa, Algeria

This work presents results of the hydrogeological and hydrochemical studies on groundwater samples from the alluvial aquifer of Merdja in Tébessa, located in the Western part of this town. Its groundwater resources are used mainly for crop irrigation in an agriculture dominated area. Hydrochemical and water quality data obtained through a sampling period (December 2008) and analysis program indicate that nitrate pollution can be a serious problem affecting groundwater due to the use of nitrogen (N) fertilizers in agriculture. The concentration of nitrate in groundwater ranged from 19 to 281 mg/l. Considerable seasonal fluctuations in groundwater quality were observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the wadi El Kebir flow regime. The chemical composition of the water is not only influenced by agricultural practices, but also by interaction with the alluvial sediments. The dissolution of evaporites accounts for part of the Na⁺, K⁺, Cl^?, SO ₄ ^2? , Mg²⁺, and Ca²⁺, but other processes, such as calcite precipitation and dedolomitization, also contribute to groundwater chemistry.     

Impact of agricultural activity and geologic controls on groundwater quality of the alluvial aquifer of the Guadalquivir River (province of Jaén,Spain): a case study

The alluvial aquifer of the Alto Guadalquivir River is one of the most important shallow aquifers in Jaén, Spain. It is located in the central-eastern part of the province, and its groundwater resources are used mainly for crop irrigation in an agriculture-dominated area. Hydrochemical and water-quality data obtained through a 2-year sampling (2004–2006) and analysis program indicate that nitrate pollution is a serious problem affecting groundwater due to the use of nitrogen (N)-fertilizers in agriculture. During the study, 231 water samples were collected from wells and springs to determine water chemistry and the extent of nitrate pollution. The concentration of nitrate in groundwater ranged from 1.25 to 320.88 mg/l. Considerable seasonal fluctuations in groundwater quality were observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Guadalquivir River flow regime. The chemical composition of the water is not only influenced by agricultural practices, but also by interaction with the alluvial sediments. The dissolution of evaporites accounts for part of the Na⁺, K⁺, Cl⁻, SO₄ ²⁻, Mg²⁺, and Ca²⁺, but other processes, such as calcite precipitation and dedolomitization, also contribute to groundwater chemistry.     

Considering groundwater use to improve the assessment of groundwater pumping for irrigation in North Africa

Groundwater resources in semi-arid areas and especially in the Mediterranean face a growing demand for irrigated agriculture and, to a lesser extent, for domestic uses. Consequently, groundwater reserves are affected and water-table drops are widely observed. This leads to strong constraints on groundwater access for farmers, while managers worry about the future evolution of the water resources. A common problem for building proper groundwater management plans is the difficulty in assessing individual groundwater withdrawals at regional scale. Predicting future trends of these groundwater withdrawals is even more challenging. The basic question is how to assess the water budget variables and their evolution when they are deeply linked to human activities, themselves driven by countless factors (access to natural resources, public policies, market, etc.). This study provides some possible answers by focusing on the assessment of groundwater withdrawals for irrigated agriculture at three sites in North Africa (Morocco, Tunisia and Algeria). Efforts were made to understand the different features that influence irrigation practices, and an adaptive user-oriented methodology was used to monitor groundwater withdrawals. For each site, different key factors affecting the regional groundwater abstraction and its past evolution were identified by involving farmers’ knowledge. Factors such as farmer access to land and groundwater or development of public infrastructures (electrical distribution network) are crucial to decode the results of well inventories and assess the regional groundwater abstraction and its future trend. This leads one to look with caution at the number of wells cited in the literature, which could be oversimplified.     

河西走廊内陆河流域农户地下水使用的影响因素分析

在农业与生态系统用水相矛盾的干旱内陆区,地下水过度开采导致生态环境急剧恶化。以往对地下水的管理,以政府直接控制地下水使用为主,但效果并不十分理想,或管理成本较大。因此,寻求间接调控地下水使用的措施成为更好的选择。以河西走廊的石羊河、黑河和疏勒河流域为例,以农户问卷调查数据为依据,探究影响农户使用地下水的关键因素,以寻求通过制定更有针对性的政策来影响农户节约并高效利用地下水,最终达到农户自下而上自发节水的效果。分析结果发现：农户对地下水的使用在不同阶段有不同的特征,但均强烈地依赖于地表水供给,地表水供给每增加1个轮次,单位公顷耕地地表水用量会增加237.3 m³,相应会减少795.2 m³的地下水,整体上平均减少504.1 m³的总用水量,地下水占灌溉总用水的比例也会下降3.7%。此外,地下水的使用还与家庭经营规模、经营模式、地下水供给条件及经营者偏好等因素密切相关。因此,政府应根据流域内地表水与地下水的综合条件和特点,结合农业生产特征和农户偏好,因地制宜制定政府主导的管理政策与农户自我调节能力有效结合的开发治理制度和方案,切实实现区域水资源节约与高效利用双重目标。     

南水北调中线河南省受水区浅层地下水水位演化规律

南水北调中线工程供水后对河南省受水区浅层地下水位、用水结构等产生了重要影响。首先回顾了河南省平原区以往地下水位埋深变化,并通过收集、统计2008—2018年河南省受水区浅层地下水位的监测成果,基于ArcGIS软件,针对南水北调中线供水前后河南省受水区浅层地下水位变化进行量化分区;结合降水量、地下水资源量、供水量等资料对供水前后河南省受水区用水结构变化等进行分析。结果表明:自20世纪60年代至2008年,河南省平原区浅层地下水位平均埋深整体逐渐增加;河南省受水区地下水资源量随降水量增加呈线性增加趋势;南水北调中线一期供水后,2015—2018年平均地下水供水量在地下水资源量中的占比较2008—2014年减少9.55%;受水区浅层地下水位有所回升,且主要体现在埋深 > 8~12 m范围向埋深 > 4~8 m及≤4 m范围的转变,埋深 > 12~16 m及 > 16~20 m范围在受水前后基本保持不变,埋深 > 20 m的区域范围有所减少;2008—2014年各监测点分布县区的浅层地下水位呈下降趋势,2015—2018年供水期间有2/3以上县区浅层地下水位逐渐恢复;农林渔业用水和工业用水占比在供水后均有所减小,城乡生活、环境综合用水占比增加明显。研究结果表明南水北调中线工程对河南省受水区浅层地下水位恢复及缓解供水矛盾问题等产生积极有效的影响。      

开采浅层水增雨水入渗引河水补源实现水资源可持续利用

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.     

Study on the Climatic Change Features of Hebei Plain

Precipitation and groundwater are essential to water circulation and they mutually influence. Groundwater is the main water supply source in Hebei Plain. On the other hand, atmospheric precipitation infiltration recharge is the main supply source of the groundwater in this area. Therefore, the studies on Hebei Plain climatic change features are of great significance to further analyze the influences of climatic changes on groundwater resources. This paper selected 10 ground climatological stations in Hebei Plain in terms of daily precipitation and temperature data from 1961 to 2010 and analyzed the spatial-temporal evolution features of temperature and precipitation. The results showed that the minimum temperature of Hebei Plain in recent 50 years increased significantly; the maximum temperature basically is stable; and the mean temperature presents an obviously increasing trend. In the spatial distribution, it gradually decreases from southwest to northeast on the whole and gradually tends to increase from the coastal to inland. The precipitation in recent 50 years owns obvious interannual change features and spatial distribution features, with a trend of overall periodic decrease and significant decrease of extreme precipitation. The annual mean precipitation intensity and annual mean extreme precipitation intensity gradually increased from piedmont plain to coastal plain. Hebei Plain has a warming and drying development trend on the whole. In space, piedmont plain belongs to the high-temperature and few-water area; coastal plain lies in low-temperature and much-water area; and central plain is in transitional zone. The climatic change and human activities are two influential factors of groundwater resources. Further revealing of the climatic change features of different geomorphic types and measuring and distinguishing of the influences of climatic change and human activities on groundwater remain to be further explored.     

典型井灌区农田土壤和地下水库调蓄汛雨径流的研究

针对80年代以来,北京市平原区地下水资源日益匮乏,必须减少径流流失与燕发消耗,利用汛雨与径流增加可用水资源,对在北京市东南郊天堂河流域水资源试验区取得的近20年的降水、地下水位等资料进行了较全面地整理;分析计算了不同水文年度0-3m层土壤水库的蓄水容量和调蓄能力;揭示了流域内不同层次地下水间的水力联系;研究了潜水、承压水随降水的多年变化关系,并证明在当前地下水埋深条件下,降水对浅层地下水位变化的影响是跨年度完成的.     

吉林省西部潜水资源与生态环境风险分析

吉林省西部是我国主要粮食产区,但区内农业水利规划管理同时面临潜水资源与生态环境双重风险。近20年来,区内曾尝试多种水资源利用模式,但缺少不同模式应用效果的定量化对比。文章建立了不同水资源利用模式,对比分析各模式的水资源与次生盐碱化风险。以洮儿河流域为例,采用循环神经网络预测2019—2023年该地区大气降水和地表水对地下水补给量;通过随机数值模拟预测现状开采、连续干旱、无序开采、地下水库建设、节水灌溉、旱田改水田6种情形下,区内潜水水位空间分布特征。以防止次生盐碱化为目标,定义水位埋深上限为1 m;以含水介质厚度为参考,定义水位埋深下限为12 m。遴选适合吉林省西部地区地下水资源可持续利用模式。结果显示:无序开采是导致区内水资源枯竭的主要诱因;地下水库建设和旱改水工程有助于潜水资源维护,但长期运行可加剧生态环境风险。节水灌溉（净采强度为2.0×108～3.0×108 m3/a）是降低区内水资源风险和生态环境风险的最佳方式。文章采用的神经网络—随机模拟分析方法成功预测了地下水位变化驱动因子和地下水位中长期变化趋势,为我国干旱半干旱地区潜水资源利用方案制定提供了新方法。     

地下水补给与开采量对降水变化响应特征:以京津以南河北平原为例

通过对京津以南河北平原年降水量、地下水补给量和农业开采量三者动态规律及其互动关系研究表明, 年降水量减增, 同期地下水补给量与开采量呈互逆变化规律, 即降水量减小, 补给量变少, 开采量增大; 年降水量增大, 补给量较多, 开采量减小.在连续枯(丰) 水年份, 当年降水量减少(增加) 10mm时, 则地下水系统水量减少7.08 (增加7.06) mm, 水位下降(上升) 5.2~8.7cm; 在10~320mm变幅内, 当年降水量减少(增加) 10%时, 则地下水系统水量减少7.98 (增加7.67) %.气候旱化过程中降水变化对引起补给量减少和开采量增加的幅度, 大于气候增雨过程中降水变化对补给量增大和开采量减少的影响程度.因此, 需要重视连续枯水年份降水变化对地下水系统影响的应对举措, 这对于提高我国北方区域地下水资源供给安全保障具有重大意义.      

黑河流域中游盆地地下水动态特征及其调蓄能力分析

40 多年来,我国西北地区大规模的地下水开发利用造成了部分地区地下水水位持续下降甚至泉水干涸,部分地区地下水仍能维持动态稳定,判断这类地区水资源开发利用是否具有可持续性是必须解决的重大科学问题。以黑河流域中游盆地作为研究对象,采用MK检验和连续小波分析等方法,分析长时间序列地下水水位数据的变化特点,研究区域地下水动态特征;结合区域水文地质条件,综合划分黑河流域中游盆地地下水补排平衡区与非平衡区;利用克里金插值法估算1990—2020 年盆地含水层对水资源的调节水量,并评价不同动态平衡区的调蓄能力。结果显示,黑河流域中游盆地地下水水位动态类型有:水文型、水文-开采型、开采型和蒸发-开采型4种长周期动态稳定型,过量开采型或上游过度引用地表水型2 种长周期持续下降型。黑河-梨园河倾斜平原、酒泉盆地和黑河中游下段侵蚀堆积平原的大厚度含水层是黑河流域中游盆地的地下水补排平衡区,其在1990—2001 年共输出地下水12.06×108 m3,2001—2020年共储存地下水9.06×108 m3。大厚度含水层为地下水的长周期调蓄提供了充足的空间,在合理控制开采量的前提下,该类含水层的天然调蓄能力可满足生产生活和下游生态用水需要。盆地地下水补排非平衡区,如黑河以东诸河倾斜平原、盐池盆地和榆木山山前诸小河流域等地区,目前的地下水开发利用方式和强度是不可持续的,应适当减少地下水开采量,调节盆地上游的引水量和开采量,抑制地下水资源枯竭。本研究成果可为西北干旱内陆地区水资源管理和持续开发利用提供参考。     

库车县南部地区地下水资源特征及开发利用对策研究

库车县南部地区位于天山南麓洪积扇扇缘及冲洪积平原地区，干旱少雨，淡水资源相当匮乏。本文在系统分析该地区地下水的形成机理，水质水量分布特征基础上，得出该地区淡水资源数量有限且在开采条件下水质易恶化的结论，并提出适量开采，控制降落漏斗降深及范围，加强保护的开发利用方案。     

早涝碱咸综合治理与生态环境良性循环

华北平原东部淡水资源短缺，旱涝碱成灾害限制了农业生产的可持续发展。海河的治理，解决了排洪排涝排咸出路。春季开发利用地下水包括微咸水和半咸水抗旱灌溉。夏季利用伏雨洗盐排咸，增大降雨入渗，减少径流流失，防治渍涝灾害，把降雨转化为地下水资源。秋冬引蓄河水，回灌地下水补源。以土壤与潜水的地层空间作为调节大气降水、土壤水、地下水、地表水的地下水库，以调控地下水埋深在临界动态为指标，最大限度地把时空分布不均的天然降雨转化为可持续利用的水资源。地表水地下水联合运用，促使水资源采补平衡，降雨灌溉淋洗脱盐强于干旱蒸发积盐过程，地下水淡化强于矿化过程。实现旱涝碱咸综合治理，水土资源可持续利用，经济社会可持续发展，生态环境良性循环。     

干旱区平原绿洲散耗型水文模型——Ⅰ模型结构

针对干旱地区平原绿洲水土资源利用的特点,建立了以农区土壤水为中心的干旱区平原绿洲散耗型水文模型。散耗型模型考虑了水在不同介质和不同形态之间的交换或转化,并重点考虑人类活动如引水灌溉、地下水的开采等对水平衡的影响。模型把研究区划分为河段、泉井、水库湖泊、农区和非农区五类水均衡模块,水均衡模块之间通过地表渠系、地下水侧渗进行水量交换。应用模型可以对研究区农区、非农区各自的蒸发量、农区向非农区地下水迁移量等干旱区主要水分散耗项进行分析。     

干旱区平原绿洲散耗型水文模型——Ⅰ模型结构

针对干旱地区平原绿洲水土资源利用的特点,建立了以农区土壤水为中心的干旱区平原绿洲散耗型水文模型。散耗型模型考虑了水在不同介质和不同形态之间的交换或转化,并重点考虑人类活动如引水灌溉、地下水的开采等对水平衡的影响。模型把研究区划分为河段、泉井、水库湖泊、农区和非农区五类水均衡模块,水均衡模块之间通过地表渠系、地下水侧渗进行水量交换。应用模型可以对研究区农区、非农区各自的蒸发量、农区向非农区地下水迁移量等干旱区主要水分散耗项进行分析。     

黑河流域径流演变规律及区域性水资源优化配置分析

经对黑河流域径流演变趋势分析研究得出结论：径流的年际变化因受降水、冰川融水、地下水三种类型混合补给，其年际变化较小，有利于水资源的利用；而径流的年内分配因受季风气候的影响，水热同步，是农业灌溉非常优越的条件，但春季来水较少，经常出现卡脖子旱。过去50年径流的总体趋势是在波动中缓慢增大，未来10年径流仍将继续缓慢增大。根据黑河中下游地区社会、经济持续发展对水资源的需求，提出了区域性水资源优化配置建议。     

华北平原农田区地下水开采量对降水变化响应

通过区域农业开采量、区域平均年末浅层地下水位对区域年降水量变化的响应特征研究,结果表明:区域农业开采量与年降水量之间存在两极互逆效应,即在枯水年份,作物需耗水量和区域农业开采量增大;在丰水年份,作物需耗水量和区域农业开采量减小。上述规律,突现了在连续枯水年份地下水对农业安全保障的特殊作用。由此,提出了农业开采量的利用水平、合理性和节水潜力以及预测的新的评价方法。