Groundwater Resources and Human Impacts in a Quaternary Intramontane Basin (L'Aquila Plain,Central Italy)

Abstract

An aquifer vulnerability study was carried out in the L'Aquila Plain of Central Italy for evaluating changes in groundwater quantity and quality induced by human activities. The L'Aquila Plain, filled with Quaternary clastic deposits, is an intramontane basin encircled by karst massifs characterized by regional groundwater, which is connected with the porous multilayer aquifer of L'Aquila Plain. The study was organized into different steps: (1) geo-lithological characterization; (2) sampling of hydrogeological data and water budget evaluation; and (3) hydrochemical and microbiological monitoring of springs and wells. The latter step made it possible to identify water-rock interaction, groundwater mixing and recharge, and to recognize the different sources of groundwater pollution. The plain aquifer, mainly recharged by the surrounding carbonate massifs, shows centripetal groundwater flowpaths. The hydrochemical features show two groundwater end-members, coming from carbonate aquifers or circulating only in the plain, with intermediate mixed groundwater. The observed ground-water pollution is negligible, but it will probably increase if the strong development of the human activities continues without groundwater protection planning.     

Basement Groundwater as a Complementary Resource for Overexploited Stream-Connected Alluvial Aquifers

The use of groundwater from alluvial aquifers largely affects stream discharge by capturing the stream resources. This affects hydrological processes and riparian biodiversity. In this study, complementary water resources are investigated in an effort to ease human pressure on alluvial systems and, eventually, on stream-aquifer relationships. Discharge and hydrochemical data along a 5 km reach of the Tordera River (NE Spain) provide evidence that groundwater fluxes, associated with a regional hydrogeological system related to the basement fracture network, contribute to alluvial recharge and to stream flow. End-member mixing analysis considering upstream discharge, groundwater flows, and human inputs to the stream as major flow sources shows that regional basement groundwater fluxes are responsible for as much as 20 % of the total discharge, which also explains unexpected rises in stream flow. This suggests a possible new approach to local water resources planning, indicating that conjunctive use might actually be feasible.     

太湖地区典型小流域地下水储量动态模拟与分析

对太湖地区典型小流域的近地表地质特征进行系统野外试验,分析近地表土层土壤和岩层结构特征,初步确定了含水层计算参数;采用三维地下水流数值模拟方法概化水文地质条件,识别与验证模型参数。结果表明:地表水补给地下水的量约是地下水补给地表水总量的2倍,山溪型小流域的地表地下水交互过程趋于单向交换,即河道水补给地下水。从含水层储水量变化看,除去蒸散发,通过地下通道流失的水量占据总水量的相当比重,且地下储水的减少量主要依赖降雨入渗进行补给。所建立的模型能够较好地反映研究区实际的水文地质条件,揭示地表水和地下水的交互量的变化过程,并定量研究流域水量平衡动态关系,可为变化环境下的地下水保护和滨湖区的地下水潜流计算研究提供预测分析依据。     

Statistical Approach for Comprehensive Planning of Watershed Development Through Artificial Recharge

The purpose of the study is to demonstrate that cross-correlation analyses can contribute to the artificial recharge study in regional level of shallow aquifer. Correlations between hydrologic time series data were analyzed to identify the hydrogeologic location for potential artificial recharge in district Surat, Gujrat, India. The natural groundwater-level fluctuations and rainfall data were used for the analyses. The effective development of groundwater resources is essential for a country like India. India receives a good amount of average annual rainfall (114?cm) but most of its part goes waste as runoff. Over exploitation of groundwater due to increasing population is an additional cause of water crisis that results in the reduction in per capita availability of water in the country. Artificial recharge is essential for effective development of groundwater resources. An effort has been made to evaluate the suitable recharge zone considering rainfall by arresting runoff to restore groundwater conditions using a statistical technique. Groundwater system in a basaltic terrain where the top weathered regolith forms shallow aquifer the water table variation is directly influenced with temporal rainfall variation. Understanding of this relation is of critical importance to management of groundwater resources. A diagnostic relationship between recharge time series and water level time series is used to serve the purpose to determine the best site for groundwater recharge.     

地下水人工回灌和停采对地面沉降控制的影响分析

地面沉降是全世界主要的工程地质灾害之一,而地下水超采是造成地面沉降的主要原因之一。为研究地下水人工回灌和停采对北京平原地面沉降的影响,采用三维地下水模型和情景设计法,设计3个情景(保持现状、人工回灌和地下水停采)对北京平原区域及沉降中心的沉降速率进行模拟。结果表明:保持现状、人工回灌和地下水停采等情景下北京平原在2015、2020和2030年的区域地面沉降分别为24 mm/a左右、12. 7～23. 2 mm/a及12. 4～23. 7mm/a,沉降中心地面沉降分别为39. 30～158. 62 mm/a、21. 09～165. 83 mm/a及16. 5～162. 95 mm/a;人工回灌和地下水停采对研究区地下水水位和含水层储存量的恢复以及地面沉降的控制有显著的促进作用,但地下水停采的效果要优于人工回灌的效果;只有综合考虑社会经济发展和地面沉降控制,才能既控制地面沉降的恶化,又保证北京平原社会的可持续发展。     

五常镇地下水水文地质特征分析

五常镇以农耕为主,为稻米之乡。五常镇70km2范围内区域的水文地质条件,受区域第四纪地质、地貌、水文和气象等因素的控制,形成了区域地下水系统的基本格局。研究地下水水文地质条件,包括地下水的赋存条件、补径排条件、类型和动态规律等,从而得出移动规律,为地下水量的计算提供基础资料,为五常镇地下水资源的评价提供水文地质依据。     

河套盆地晚更新世以来黄河改道对高砷地下水分布的控制机制

针对河套盆地开展了历时多年的水文地质环境地质调查,利用采集的298组浅层地下水样品以及收集并甄选的382个水文地质钻孔记录分析发现:河套盆地内95%的高砷地下水(As质量浓度10μg/L)集中在黄河决口、改道形成的古河道影响带及黄河决口扇裙带。其中,盆地南部首次发现了较为集中的高砷地下水,其分布范围与黄河北岸的晚更新世以来黄河决口、改道形成的4个大型决口扇,在空间上有着良好的对应关系。黄河古河道带及决口扇裙带表现为较强的还原环境及蒸发浓缩作用以及较弱的地表水补给强度。受pH值、含铁氧化物的还原性溶解等因素影响,决口扇裙带浅层地下水中砷的含量略低于平原中部黄河古河道带。结果表明:黄河古河道带及决口扇裙带特定的沉积环境控制着地下水的水文地球化学过程,进而对高砷地下水的分布具有决定性的作用。     

高开采强度下库尔勒市地下水位埋深动态与影响因素浅析

库尔勒市社会经济快速发展对水资源的需求使其地下水开发经历了临界超采期(2000—2006年)、超采增长期(2007—2011年)和高位超采稳定期(2012—2015年)过程。为探究高开采强度下的地下水位埋深动态特征,以库尔勒市地下水监测网覆盖区作为研究区,对以上3个开采强度时段地下水位埋深进行线性趋势分析。所有监测井地下水位埋深均呈持续增大趋势,研究区2000—2011年地下水位埋深总体呈“加速”增大状态;2012—2015年转变为“减速”增大状态。地下水长期超采已使山前倾斜平原地下水位埋深累计增大4.10～12.67 m,冲积平原累计增大9.07～22.26 m,天然生态受到威胁。逐步回归分析表明,研究区监测井地下水位埋深与径流量呈负相关关系,与地下水开采量呈正相关关系,径流量、开采量实质是研究区地下水补给项与排泄项的综合反映。地下水位埋深持续增大是地下水补给量减少、地下水开采强度增大共同作用的结果。研究成果可为库尔勒市水资源开发利用与保护提供一定的参考。     

新疆玛纳斯河流域典型剖面地下水位动态分析

新疆玛纳斯河流域是水资源开发力度较大、经济发展水平较高的地区。对玛纳斯河流域13眼监测井组成典型剖面的2010年-2014年监测数据进行趋势性分析得出,整个监测剖面地下水位呈持续下降趋势,上部冲洪积平原单一潜水区地下水位下降速率为0.65~0.83m/a(平均0.74m/a);中部潜水溢出带地下水位下降速率为1.12m/a;冲积细土平原区上部、下部地下水位下降速率分别为0.59~3.07m/a(平均1.77m/a)和0.35~3.98m/a(平均2.41m/a);地下水位年下降速率由上游至下游呈增大趋势。在年内变化上,冲洪积平原单一潜水区埋深变化为"降-升-降";潜水溢出带及以北区域为"升-降-升"。地下水动态类型除上部冲洪积平原单一潜水区为入渗-径流型外,潜水溢出带至冲积细土平原区均为开采型。区域地下水位持续下降使现状地下水埋深(5.89~67.46m)远大于6.0m荒漠化临界埋深,生态环境面临恶化。通过对石河子市、玛纳斯县水资源利用分析得出,地下水位持续下降的因素是地下水超采、区域水资源高效利用使地下水补给量减小双重作用下形成的。提出必须科学规划用水,缩减灌溉面积和地下水开采量,开展生态补偿机制,使流域经济社会可持续发展。     

Development of a Rainfall-Recharge Relationship for a Fractured Basaltic Aquifer in Central India

Groundwater being an important component of the hydrological cycle, estimation of its annual replenishment is essential to evolve a plan for optimum utilization. Groundwater balance approach, which is used extensively for the quantification of recharge and discharge components has been adopted for the rainfall-recharge estimation. Various inflow and outflow components have been identified and estimated for Sagar block in Sagar district of Madhya Pradesh, which faces acute water scarcity and continuous decline in groundwater levels. The computed recharge from rainfall varies between 122.45 and 183.71 MCM. The computed rainfall-recharge is compared with the Chaturvedi (1973), Kumar and Seethapathi (2002), Krishna (1987), and U.P. Irrigation Research Institute models. Models have also been developed to estimate rainfall-recharge for varying ranges of the annual rainfall and have been compared with the existing models. The relative error in estimation of rainfall-recharge from proposed models varies between 0.03 and 9.24%. The overall scenario is net decline in groundwater storage to an extent of ?31.31 MCM over a period of 16 years from 1985–1986 to 2000–2001. The trend analysis by Kendall’s rank correlation test, regression test for linear trend and Mann–Kendall test also clearly suggests falling trends in groundwater storage at 5% significant level, thereby demonstrating over-exploitation of the groundwater aquifer. This has subsequently led to progressive decline in groundwater table in the study area. Efforts should be initiated to tap the surface water by creating storages at suitable sites and artificial recharge practices should be encouraged after identifying suitable recharge zones. Conjunctive use of the surface and groundwater along with water conservation practices and groundwater management measures should be taken up to arrest the progressive decline in groundwater levels and over-exploitation of groundwater aquifer.     

平原区截渗排水渗流计算方法的研究与探讨

描述了非完整沟(管)工程布设形式和补给出流条件,对现行的平原区截渗排水渗流计算方法进行了综合分析,针对单、双沟的对称和非对称布设形式,提出了系列的有限含水层厚度条件下,对称与非对称单、双沟截渗排水的渗流水动力学计算公式。计算结果表明,在补给和出流条件基本相同的情况下,双沟比单沟截取地下水量和降低地下水位的作用都明显增大。     

伊犁河谷西部平原多级次地下水循环模式

分析伊犁河谷西部平原区地质条件与水文地质条件,结合2017、2018年研究区内采集的220组地表水及地下水样品的水化学、D、~(18)O、~3 H及CFCs等指标测试结果,以伊犁河南北岸2个典型剖面为重点,分析了区域地下水环境同位素和水化学的空间分布特征。伊犁河谷西部平原区地下水主要接受山区降水补给,地形地貌和含水层岩性变化是控制区内地下水循环最主要的影响因素,区内地下水循环表现为多级次的循环演化特点,以伊犁河为界,伊犁河谷西部平原区南北两侧地下水水流系统可划分为局部、中间和区域等3个级次的地下水流系统。不同级次的地下水水流系统在循环范围和深度上存在一定差异。     

巧家县龙洞地下河岩溶水系统及其补给关系分析

基于云南省巧家县荞麦地河流域岩溶水文地质调查之上,主要对整个流域的一个岩溶水子系统即龙洞地下河岩溶水系统的地下水补给关系进行分析研究。首先通过其区域的水文地质特征及实地调查分析,确定其地表水渗漏为地下水补给重要来源,然后对该岩溶水系统的水样数据进行水化学分析,运用Auto CAD软件绘制Piper三线图,使用三线图示法分析该岩溶水系统地表水和地下水水化学特征,进一步验证区域内地表水和地下水的补给关系和联系。     

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。     

人类开采活动影响下的衡水地区地下水水质特征及演化

衡水地区地下水普遍存在"上咸下淡"的水质格局,受深部淡水持续超采影响,浅层咸水有逐年下移而使淡水咸化的趋势。选择衡水地区典型剖面,通过水质长期监测,结合地下水开采情况,分析2011至2014年该剖面上地下水水位与水质监测资料,总结了衡水地区地下水水化学特征及其演化规律。研究结果表明,浅层含水层中水平径流微弱,地下水水质由西向东逐渐好转,其中西部地下水离子浓度变化较大;深部含水层中水平径流明显,地下水水质整体良好,但有逐年恶化的趋势;人类开采活动一定程度上增强了浅层和深层含水层间的水力联系,使二者中离子浓度随时间的波动呈现出一定的相关性。     

孔隙承压水盆地超采评价与限采规划

为客观评价孔隙承压含水层的超采程度，以地下水资源的可循环再生能力作为可持续开采的约束，通过对各项补给的来源、途径和性质的分析，确定可持续开采量的构成。文中以安徽淮北平原西部孔隙承压水盆地超采评价为例，对上述过程进行阐述，结合承压水流系统的数值模型，评价研究区的可持续开采量和超采程度，并在此基础上，提出限采规划方案。     

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.     

Natural recharge to sustainable yield from the barind aquifer: a tool in preparing effective management plan of groundwater resources.

This paper presents the results of water balance study and aquifer simulation modeling for preliminary estimation of the recharge rate and sustainable yield for the semi arid Barind Tract region of Bangladesh. The outcomes of the study are likely to be useful for planning purposes. It is found from detailed water balance study for the area that natural recharge rates in the Barind Tract vary widely year to year. It may have resulted from the method used for the calculation. If the considered time interval had been smaller than the monthly rainfall, the results could have been different. Aquifer Simulation Modeling (ASM) for the Barind aquifer is used to estimate long-term sustainable yield of the groundwater considering limiting drawdown from the standpoint of economic pumping cost. In managing a groundwater basin efficiently and effectively, evaluation of the maximum annual groundwater yield of the basin that can be withdrawn and used without producing any undesirable effect is one of the most important issues. In investigating such recharge rate, introduction of certain terms such as sustainable yield and safe yield has been accompanied. Development of this area involves proper utilization of this vast land, which is possible only through ensured irrigation for agriculture. The Government of Bangladesh has a plan to develop irrigation facilities by optimum utilization of available ground and surface water. It is believed that the groundwater table is lowering rapidly and the whole region is in an acute state of deforestation. Indiscriminate groundwater development may accelerate deforestation trend. In this context estimation of actual natural recharge rate to the aquifer and determination of sustainable yield will assist in proper management and planning of environmentally viable abstraction schemes. It is revealed from the study that the sustainable yield of ground water (204 mm/y) is somewhat higher than the long-term annual average recharge (152.7 mm) to the groundwater reservoir. The reason behind this is that the rivers within and around the Barind Tract might have played the role of influent rivers.     

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。     

Modeling Anthropogenic Impacts and Hydrological Processes on a Wetland in China

In many rapidly urbanizing countries like China, wetlands are constantly affected by anthropogenic factors such as landscaping, additional abstractions, reduction in catchment perviousness, etc. Thus, modeling of such anthropogenic factors should be explicitly considered when simulating wetlands. In this paper, the wetland module in a distributed hydrological model, SWAT, is modified to simulate the artificial water input to the designated wetlands. Local river runoff is used as the water sources to study the wetland restoration potential and to analyze the effects on local hydrological cycle and sea outflow. The QingDianWa depression, near Tianjin city, China, is used as a case study to study the restoration impact. Results showed that after restoration, the QinDianWa depression can reduce the potential impact of flooding by an average of 61 million m³ per year, increase the annual surface runoff by about 32 million m³ in non-flood seasons, and increase groundwater recharge by 9.4 million m³. This illustrated the importance of wetland restoration on flood control, river flow increase, groundwater recharge, and flood reclamation. But with local water resources is far from meeting the demands of wetland restoration, the actual restored water surface area is only 21.5 and 40.9 km² for the designated surface areas of 60 and 150 km² respectively. Compared with nature wetlands without human disturbance, the anthropogenic effect of reduction of runoff and groundwater recharge may be attributed to large amount of human consumption of local water. However, the results showed that the aims of restoring Tianjin wetlands cannot be achieved fully by relying solely on local water resources. It is necessary to consider a combination of external sources of water and using artificial recharge from reclaimed water.