Groundwater Reservoir Research Articles

Mechanism of the Original Ecology Gravity Irrigation in the Ziquejie Terrace

The Ziquejie Terrace is one of the three famous ancient terraces in China. Rice has been planted in large area with mountains standing and a lot of steep hills. Whatever the weather is drought or rainstorm, the rice can always have a good harvest without water storage facilities. To reveal the mechanism of the original ecology gravity irrigation, several investigations had been developed such as observation of hydrology and meteorology, hydro-geological exploration and dynamic monitoring of groundwater level. According to the results of the experimental observations, this article proposed a suit of perfect theories and methods, such as the nonlinear autonomic regulation theory and “the ground water reservoir on the same slope position” theory in ancient terrace area. Further more, the calculation model of the original ecology gravity irrigation water cycle balance was established and a set of theories and methods of the water cycle balance calculation were formed on the basis of prior theories. Using this model, the process of irrigation water supply and demand balance, as well as the irrigation assurance, was simulated at rice growth stages in the original gravity irrigation area and its surrounding artificial irrigation area. The results showed that there is a highly consistency between the simulation results and the measured results, and it revealed the mechanism of ancient ecological gravity irrigation profoundly in terraces area. The result of study has important directive significance to the exploitation and protection of the terrace in China and has important reference value to the exploitation of the slope farmland.

Major groundwater reservoir nr 112 in the coast of Gdańsk Bay

The main groundwater reservoirs (MGR) in Poland have been established during last 9 years and finished in 2017 yr. (Mikołajków, Sadurski edit.). The most reach in groundwater resources hydrogeological structures in the country where deliminated and the scope of limited and forbidden human activities for their protection where established. Area of main groundwater reservoir nr 112 , named - Żuławy Gdańskie - comprises predominantly City of Gdańsk and area of Gdańsk and Pruszcz Gdański Counts and slightly exceeds 100 km2. The area undertaken for the investigation and modelling was 363.8 km2. The aim of MGR delimitation and hydrogeological documentation was the water resources protection based on physical planning proper, responsible water management (Herbich et al., 2009). The methods of hydrogeological researches, groundwater resources calculation and delimitation of MGR is presented in the paper.

Cryospheric Hydrometeorology Observation in the Hulu Catchment (CHOICE), Qilian Mountains, China

Core Ideas CHOICE is an observation platform for field, hillside, catchment and mountainous basin scales. A distributed hydrological model including cryospheric hydrology data is needed. CHOICE is an open cryospheric hydrology observation and research system. Understanding cryospheric hydrology and the effects of cryospheric changes on river runoff is critical for sustainable water management especially in arid inland river basins such as those in northwest China where water resources mainly come from alpine areas. A cryospheric hydrometeorology observation system (CHOICE) has been established since 2008 in the Hulu catchment, which is a well‐instrumented experimental and representative catchment in the upper reaches of the inland Hei River, Qilian Mountains, northwest China. The CHOICE includes dense meteorological measurements from 2980 to 4800 m asl (e.g. glacier, snow, and permafrost hydrology) and water and heat balance in the vertical landscape zones including alpine grassland, meadow, shrub, coniferous forest, marshy meadow, and moraine‐talus zones. The comprehensive long‐term observations available for the CHOICE provide the basis for model development and application in cryospheric hydrological research. We focus on cryospheric hydrometeorological process of precipitation, freeze–thaw cycle, energy balance, soil–vegetation–atmosphere transfer (SVAT), runoff, groundwater reservoir, and hydrological resiliency within vertical elevation in CHIOCE. Data from CHOICE, an open cryospheric hydrology observation and research system, is accessed through a website (http://hhsy.casnw.net/) and the WestDC database (http://westdc.westgis.ac.cn/).

Salt water intrusion in the breakthrough valley of the river Aa between the Flemish coastal plain and the Saint Omer basin (France)

The salinity distribution in a breakthrough valley has been studied based on field observations and using a numerical model. The studied valley is located in Northern France between the Saint Omer basin and the Flemish coastal plain. The field campaign starts with the installation of observation wells. In these observations wells the electrical conductivity is logged versus depth with an electro-magnetic device. These wells also allow the necessary measurements to deduce the fresh water heads. Some of the wells are used for the performance of a pumping test. The lateral variation of the electrical conductivity of the water in the drainage canals is measured. With a numerical model the evolution of the flow and distribution of the fresh and salt water are simulated. Two simulations are made with the same schematization of the groundwater reservoir consisting of quaternary marine sediments, silt and clay and with the same hydraulic and solute parameters and boundary conditions but with two different initial salinity distributions. The results of both simulations show that the salinity distribution in the quaternary marine sediments depends not only on the lateral variation of the watertable but also on the shape of the incision of the palaeo-valley into the clay of Ypresian age. The salinity distribution in the lower part of the quaternary marine sediments depends first and foremost on the shape of the incision of the palaeo-valley into the clay of Ypresian age whereas the salinity distribution in the upper part of the quaternary marine sediments depends first and foremost on the lateral variation of the watertable.

The climate changes in the sub-basin of the Oum Er rbia central and the impact on the surface waters.

Observations and model results indicate that climate trends in North Africa show both drying and warming over the past few decades, according to the latest Intergovernmental Panel on Climate Change (IPCC) assessment. During the last decades, due to changes in climatic and environmental conditions, water resources available in Morocco are decreasing. They are, moreover, subject to extreme cyclical variations and to soaring water demands because of rapid population growth, improvement of living standards, industrial development and expansion of irrigated agriculture. The pressure on these water resources is accompanied by a growing and increasingly serious degradation of their quality. This is found at the level of average of air temperatures that are continuously growing and at the level of precipitation with an average potential of water in the area with a significant decrease in the last forty years. The purpose of this work is to make a study on the impact of climate change on water resources that exist in the basin of the Oum Er Rbia Central, and to give justifiable results regarding the evolution of climate change over time. From the created database, we brought out diagrams, curves and maps of the evolution of climate change that show the results below: The study of the evolution of rainfall recorded since 1934 and the breaks in time series highlighted two methodologically distinct periods: a wet period with high rainfall (1986 - 1971), a dry season and low rainfall (1970/71 to 2007). Observed climatic trends, calculated over the period of 1935-2007 and reported in the study, indicate the following: On an annual basis, changes in precipitation were not significant and varied from one region to another. On the other hand, spring rainfall declined significantly in the northern part of Morocco at a rate of 0.5 mm / day per decade; That the area experienced an average annual rainfall reduction of 70 mm (20%) over this period compared to 1940-1980. The area is a hydraulic region that is already experiencing a water deficit. The sharp decline in water supplies since 1980-2007 (by 40% compared with 1940- 1980) and the increase in demand and water degradation by different causes; The annual average flows measured at the the central Oum Er Rbia stations were reduced by considerable hydrological deficits ranging between 40.8 and 49.5%. Global warming and rainfall regression are added to the intrinsic conditions of sub basins of the Oum Er Rbia Central (especially waterproofing of land and the lack of groundwater reservoir) to increase its vulnerability to water scarcity. This critical situation requires adapting good management methods of meteorological water as the only source of water in this basin.You should leave 8 mm of space above the abstract and 10 mm after the abstract. The heading Abstract should be typed in bold 9- point Arial. The body of the abstract should be typed in normal 9-point Times in a single paragraph, immediately following the heading. The text should be set to 1 line spacing. The abstract should be centred across the page, indented 17 mm from the left and right page margins and justified. It should not normally exceed 200 words.

Identification of active denitrifiers by DNA-stable isotope probing and amplicon sequencing reveals Betaproteobacteria as responsible for attenuation of nitrate contamination in a low impacted aquifer.

Groundwater reservoirs constitute important freshwater resources. However, these ecosystems are highly vulnerable to contamination and have to rely on the resident microbiota to attenuate the impact of this contamination. Nitrate is one of the main contaminants found in groundwater, and denitrification is the main process that removes the compound. In this study, the response to nutrient load on indigenous microbial communities in groundwater from a low impacted aquifer in Uruguay was evaluated. Denitrification rates were measured in groundwater samples from three different sites with nitrate, acetate and pyrite amendments. Results showed that denitrification is feasible under in situ nitrate and electron donor concentrations, although the lack of readily available organic energy source would limit the attenuation of higher nitrate concentrations. DNA-stable isotope probing, combined with amplicon sequencing of 16S rRNA, nirS and nirK genes, was used to identify the active denitrifiers. Members of the phylum Betaproteobacteria were the dominant denitrifiers in two of three sites, with different families being observed; members of the genus Vogesella (Neisseriaceae) were key denitrifiers at one site, while the genera Dechloromonas (Rhodocyclaceae) and Comamonas (Comamonadaceae) were the main denitrifiers detected at the other sites.

Groundwater origin and recharge in the hyperarid Cordillera de la Costa, Atacama Desert, northern Chile

The Cordillera de la Costa is located along the coastline of northern Chile, in the hyperarid Atacama Desert area. Chemical and isotopic analyses of several small coastal springs and groundwater reservoirs between 22.5 °S and 25.5 °S allow understanding groundwater origin, renewal time and the probable timing of recharge. The aquifers are mostly in old volcanic rocks and alluvial deposits. All spring waters are brackish, of the sodium chloride type due to intensive concentration of precipitation due aridity and for deep groundwater to additional water-rock interaction in slowly renewed groundwater and mixing with deep seated brines. The heavy δ18O and δ2H values in spring water are explained by recharge by the arrival of moist air masses from the Pacific Ocean and the originally lighter values in the deep wells can be associated to past recharge by air masses coming from the Atlantic Ocean. Current recharge is assumed almost nil but it was significant in past wetter-than-present periods, increasing groundwater reserves, which are not yet exhausted. To explain the observed chloride content and radiocarbon (14C) activity, a well-mixed (exponential) flow model has been considered for aquifer recharge. The average residence time of groundwater feeding the springs has been estimated between 1 and 2kyr, up to 5kyr and between 7 and 13kyr for deep well water, assuming that current recharge is much less than during the previous wetter period. The recharge period feeding the coastal springs could have been produced 1 to 5kyr BP, when the area was already inhabited, and recharge in the Michilla mine was produced during the 10 to 14.5kyr BP CAPE (Central Andean Pluvial Event) pluvial events of the central Andes. The approximate coincidence of turnover time with the past wet periods, as revealed by paleoclimate data, points to significant recharge during them.

Multi-reservoir fluid mixing processes in rift-related hydrothermal veins, Schwarzwald, SW-Germany

Fluid mixing is an important process in the formation of many hydrothermal vein-type deposits. Here, we present evidence from hydrothermal fluorite-barite-quartz veins with Pb-Zn-Cu-(Ag)-sulfides and associated mineralization, indicating that mineral precipitation was initiated by mixing of fluids derived from multiple sources, including mixing between more than two end-member fluid compositions. Based on our observations, we relate the diversity of the hydrothermal veins of the Schwarzwald mining district in terms of mineral assemblage and fluid inclusion chemistry to the disturbed and transient geological environment during ongoing rifting. Literature data on the regional geology, current groundwater reservoirs, formation processes and hydraulic features are augmented by new fluid inclusion analyses from post-Cretaceous, hydrothermal vein minerals including microthermometry, crush leach, Microraman and LA-ICP-MS analyses of individual fluid inclusions.Petrography and microthermometry of fluid inclusions show complex sequences of alternating fluid signatures within different growth zones of one crystal. High (20–26wt% NaCl+CaCl2), moderate (5–20wt% NaCl+CaCl2) and low salinity (<5wt% NaCl+CaCl2), sulfate- and/or CO2-bearing primary fluids were trapped during crystal growth. Such variations are commonly observed in minerals from different localities. Bulk crush leach analyses show significant variations in major element composition of the trapped fluids, within the overall Na-Ca-Cl-SO4-HCO3-system. These variations are caused by mixing of fluids from different aquifers and in various proportions. Ancient fluids show chemical similarities to modern groundwater aquifers that are available for direct sampling, such as granitic basement, Lower Triassic sandstones or Middle Triassic limestones and evaporites. Analyses of individual fluid inclusions by LA-ICP-MS support this interpretation and document the multi-component fluid mixing processes at individual localities recorded on the scale of single crystal growth zones. The latter data are used in a diffusion model to obtain the duration of mineral growth (before the fluid is homogenized), which implies very short-lived fluid events on the order of seconds to hours.By defining end member fluids and their proportions, we show that nearly all fluid mixtures are saturated with respect to barite. By contrast, fluorite-saturated fluids can only be modelled by mixing of a basement brine with fluids from Triassic sandstones. All fluid mixtures are strongly undersaturated with respect to galena, chalcopyrite and sphalerite, the most commonly observed ore minerals in the hydrothermal veins. As the calculated fluid mixtures are typically relatively oxidized and contain high sulfate/sulfide ratios, precipitation of sulfides was probably related to short-lived reduction events caused by an influx of hydrocarbons, by reactions with graphitic wall rocks in fractures by sulfidation related to fluid-rock reaction with the surrounding host rocks or an external influx of hydrocarbon-bearing fluids. The multi-aquifer fluid mixing processes involving aquifers of different chemical and physical constitution were triggered by brittle deformation related to rifting of the Rhine graben. This appears to be essential for the formation of a large number of mineralogically diverse hydrothermal ore deposits.

Aquifer configuration and geostructural links control the groundwater quality in thin-bedded carbonate–siliciclastic alternations of the Hainich CZE, central Germany

Abstract. The quality of near-surface groundwater reservoirs is controlled, but also threatened, by manifold surface–subsurface interactions. Vulnerability studies typically evaluate the variable interplay of surface factors (land management, infiltration patterns) and subsurface factors (hydrostratigraphy, flow properties) in a thorough way, but disregard the resulting groundwater quality. Conversely, hydrogeochemical case studies that address the chemical evolution of groundwater often lack a comprehensive analysis of the structural buildup. In this study, we aim to reconstruct the actual spatial groundwater quality pattern from a synoptic analysis of the hydrostratigraphy, lithostratigraphy, pedology and land use in the Hainich Critical Zone Exploratory (Hainich CZE). This CZE represents a widely distributed yet scarcely described setting of thin-bedded mixed carbonate–siliciclastic strata in hillslope terrains. At the eastern Hainich low-mountain hillslope, bedrock is mainly formed by alternated marine sedimentary rocks of the Upper Muschelkalk (Middle Triassic) that partly host productive groundwater resources. Spatial patterns of the groundwater quality of a 5.4 km long well transect are derived by principal component analysis and hierarchical cluster analysis. Aquifer stratigraphy and geostructural links were deduced from lithological drill core analysis, mineralogical analysis, geophysical borehole logs and mapping data. Maps of preferential recharge zones and recharge potential were deduced from digital (soil) mapping, soil survey data and field measurements of soil hydraulic conductivities (Ks). By attributing spatially variable surface and subsurface conditions, we were able to reconstruct groundwater quality clusters that reflect the type of land management in their preferential recharge areas, aquifer hydraulic conditions and cross-formational exchange via caprock sinkholes or ascending flow. Generally, the aquifer configuration (spatial arrangement of strata, valley incision/outcrops) and related geostructural links (enhanced recharge areas, karst phenomena) control the role of surface factors (input quality and locations) vs. subsurface factors (water–rock interaction, cross-formational flow) for groundwater quality in the multi-layered aquifer system. Our investigation reveals general properties of alternating sequences in hillslope terrains that are prone to forming multi-layered aquifer systems. This synoptic analysis is fundamental and indispensable for a mechanistic understanding of ecological functioning, sustainable resource management and protection.

Multivariate statistical analysis to characterize/discriminate between anthropogenic and geogenic trace elements occurrence in the Campania Plain, Southern Italy.

Shallow aquifers are the most accessible reservoirs of potable groundwater; nevertheless, they are also prone to various sources of pollution and it is usually difficult to distinguish between human and natural sources at the watershed scale. The area chosen for this study (the Campania Plain) is characterized by high spatial heterogeneities both in geochemical features and in hydraulic properties. Groundwater mineralization is driven by many processes such as, geothermal activity, weathering of volcanic products and intense human activities. In such a landscape, multivariate statistical analysis has been used to differentiate among the main hydrochemical processes occurring in the area, using three different approaches of factor analysis: (i) major elements, (ii) trace elements, (iii) both major and trace elements. The elaboration of the factor analysis approaches has revealed seven distinct hydrogeochemical processes: i) Salinization (Cl-, Na+); ii) Carbonate rocks dissolution; iii) Anthropogenic inputs (NO3-, SO42-, U, V); iv) Reducing conditions (Fe2+, Mn2+); v) Heavy metals contamination (Cr and Ni); vi) Geothermal fluids influence (Li+); and vii) Volcanic products contribution (As, Rb). Results from this study highlight the need to separately apply factor analysis when a large data set of trace elements is available. In fact, the impact of geothermal fluids in the shallow aquifer was identified from the application of the factor analysis using only trace elements. This study also reveals that the factor analysis of major and trace elements can differentiate between anthropogenic and geogenic sources of pollution in intensively exploited aquifers.

Physical Experiment and Numerical Simulation of the Artificial Recharge Effect on Groundwater Reservoir

To improve the efficiency of utilizing water resources in arid areas, the mechanism of artificial recharge effecting on groundwater reservoir was analyzed in this research. Based on a generalized groundwater reservoir in a two-dimensional sand tank model, different scenarios of the infiltration basin location and recharge intensity are designed to study how to improve the efficiency of groundwater reservoir artificial recharge. The effective storage capacity and the effective storage rate are taken as the main parameters to analyze the relation between recharge water volume and storage capacity. By combining with groundwater flow system theory, FEFLOW (Finite Element subsurface FLOW system) is adopted to set up the groundwater numerical model. It is used to verify the experiment results and to make deep analysis on the rule of water table fluctuations and groundwater movement in the aquifer. Based on the model, different scenarios are designed to examine the combined effect of recharge intensity and intermittent periods. The research results show that: the distance between infiltration basin and pumping well should be shortened appropriately, but not too close; increasing recharge intensity helps to enlarge the effective storage capacity, but it can also reduce the effective storage rate, which goes against the purpose of effective utilization of water resources; and, the recharge intensity and recharge duration should be given full consideration by the actual requirements when we take the approach of intermittent recharge to make a reasonable choice.

The Source, Flow Rates, and Hydrochemical Evolution of Groundwater in an Alluvial Fan of Qilian Mountain, Northwest China

Major ions and selected environmental tracers (D, 18O, 3H and chlorofluorocarbons (CFCs)) were employed to determine the source, flow rates, and hydrochemical evolution of groundwater in an alluvial fan along the front of the Qilian Mountains, which serves as an important groundwater reservoir in northwest China. Temporal and spatial variations in ion concentrations were limited near the upper portion of the alluvial fan. However, groundwater quality deteriorated along the flow path as concentrations of Mg2+, Na+, SO42−, and Cl− increased toward the fan toe and into the center of the valley. The relative abundance of the major cations and anions also changed down-fan from Ca2+ to Na+ and Mg2+, and from HCO3− to SO42− and Cl−, respectively. Isotopic data suggests that precipitation within the Qilian Mountains, which recharged the alluvial deposits near the mountain front, was the primary source of groundwater. Apparent groundwater ages determined by CFCs varied from 23 to 40 years, and in general, increased in age from south to north (down-fan). It is concluded that groundwater in the study area was recharged by the Qilian Mountains, flowed through the alluvial fan from south to north, and was subsequently discharged several decades later from springs located along the toe of the fan, after which it re-entered the Shule River.

Using environmental isotopes along with major hydro-geochemical compositions to assess deep groundwater formation and evolution in eastern coastal China

Hydrochemical analysis and environmental isotopic tracing are successfully applied to study groundwater evolution processes. Located in eastern China, the Jiangsu Coastal Plain is characterized by an extensively exploited deep groundwater system, and groundwater salinization has become the primary water environmental problem. This paper provides a case study on the use of a hydrochemical and environmental isotopic approach to assess possible mixing and evolution processes at Yoco Port, Jiangsu Province, China. Hydrochemical and isotopic patterns of deep groundwater allow one to distinguish different origins in deep water systems. HCO3– is the dominant anion in the freshwater samples, whereas Na+ and Cl− are the dominant major ions in the saline samples. According to δ18O, δ2H and 14C dating, the fresh water is derived from precipitation under a colder climate during the Glacial Maximum (Dali Glacial), while the saline groundwater is influenced by glacial-interglacial cycles during the Holocene Hypsithermal. The δ18O, δ2H and 3H data confirm that deep groundwater in some boreholes is mixed with overlying saline water. The deep groundwater reservoir can be divided into a saline water sector and a fresh water sector, and each show distinct hydrochemical and isotopic compositions. The saline groundwater found in the deep aquifer cannot be associated with present seawater intrusion. Since the Last Glacial Maximum in the Late Pleistocene, the deep groundwater flow system has evolved to its current status with the decrease in ice cover and the rising of sea level. However, the hydraulic connection is strengthened by continuous overexploitation, and deep groundwater is mixed with shallow groundwater at some points.

Evaluating Model Simulations of Twentieth-Century Sea-Level Rise. Part II: Regional Sea-Level Changes

Twentieth-century regional sea level changes are estimated from 12 climate models from phase 5 of the Climate Model Intercomparison Project (CMIP5). The output of the CMIP5 climate model simulations was used to calculate the global and regional sea level changes associated with dynamic sea level, atmospheric loading, glacier mass changes, and ice sheet surface mass balance contributions. The contribution from groundwater depletion, reservoir storage, and dynamic ice sheet mass changes are estimated from observations as they are not simulated by climate models. All contributions are summed, including the glacial isostatic adjustment (GIA) contribution, and compared to observational estimates from 27 tide gauge records over the twentieth century (1900–2015). A general agreement is found between the simulated sea level and tide gauge records in terms of interannual to multidecadal variability over 1900–2015. But climate models tend to systematically underestimate the observed sea level trends, particularly in the first half of the twentieth century. The corrections based on attributable biases between observations and models that have been identified in Part I of this two-part paper result in an improved explanation of the spatial variability in observed sea level trends by climate models. Climate models show that the spatial variability in sea level trends observed by tide gauge records is dominated by the GIA contribution and the steric contribution over 1900–2015. Climate models also show that it is important to include all contributions to sea level changes as they cause significant local deviations; note, for example, the groundwater depletion around India, which is responsible for the low twentieth-century sea level rise in the region.

Cupriavidus pinatubonensis AEO106 deals with copper-induced oxidative stress before engaging in biodegradation of the herbicide 4-chloro-2-methylphenoxyacetic acid

BackgroundMicrobial degradation of phenoxy acid (PA) herbicides in agricultural soils is important to minimize herbicide leaching to groundwater reservoirs. Degradation may, however, be hampered by exposure of the degrader bacteria to toxic metals as copper (Cu) in the soil environment. Exposure to Cu leads to accumulation of intracellular reactive oxygen species (ROS) in some bacteria, but it is not known how Cu-derived ROS and an ensuing oxidative stress affect the degradation of PA herbicides. Based on the previously proposed paradigm that bacteria deal with environmental stress before they engage in biodegradation, we studied how the degradation of the PA herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) by the model PA degrader Cupriavidus pinatubonensis AEO106 was affected by Cu exposure.ResultsExposure of C. pinatubonensis in batch culture to sublethal concentrations of Cu increased accumulation of ROS measured by the oxidant sensing probe 2,7-dichlorodihydrofluorescein diacetate and flow cytometry, and resulted in upregulation of a gene encoding a protein belong to the Ohr/OsmC protein family. The ohr/osmC gene was also highly induced by H2O2 exposure suggesting that it is involved in the oxidative stress response in C. pinatubonensis. The increased ROS accumulation and increased expression of the oxidative stress defense coincided with a delay in the catabolic performance, since both expression of the catabolic tfdA gene and MCPA mineralization were delayed compared to unexposed control cells.ConclusionsThe current study suggests that Cu-induced ROS accumulation in C. pinatubonensis activates a stress response involving the product of the ohr/osmC gene. Further, the stress response is launched before induction of the catabolic tfdA gene and mineralization occurs.

Overexploitation and cumulative drought trend effect on Ras El Ain karstic spring discharge (Khabour Sub-basin, Syria)

The effects of climate change and overexploitation are being strongly perceived in the studied area and the springs discharge is obviously affected. In this paper, Ras El Ain spring discharge and precipitation were analyzed by normalized methods on an yearly timescale. The deficit of Ras El Ain spring discharge due to overexploitation factors and drought effects was estimated. Cumulative drought analyses were carried out using SPI10 and SQI10. Finally, the decreasing trends of the spring discharge due to the deficiency in rainfall were analyzed. The main results reveal that the annual mean deficit of Ras El Ain spring discharge due to overpumping was between 32 and 45%, whereas, annual mean deficit related to drought was between 22 and 35% on average, during the last 30 years (post-1984). The moving averages of SPI and SQI delineate very well the drought periods during last three decades. The cumulative droughts using SPI10 and SQI10 reveal that wet period (pre-1984) with positive values was characterized by high precipitation and spring discharge. Overexploitation period (1984–1989) is distinguished by decreasing SQI10 values whereas, SPI10 is almost stable. The response of the karst system to the precipitation signal has been changed, during the drought period (1990–2000), and the spring behaviour has been modified due to the first overexploitation period. Finally, overexploitation period (2001–2008) is related to the second phase of groundwater intensive pumping for irrigation purposes. Consequently, this period is completely catastrophic causing the drying up of the spring. The decreasing trends analyzed using DPI and DQI showed annual decreasing rates relative to the mean values of −0.268% and −0.105%, respectively. Thus, the results of theoretical model reveal that precipitation will decrease by about \(\hbox {DPI} = -20.7\)% and the discharge will decline by about −9.2% by 2050. Consequently, the declining discharge due to climatic variation under natural conditions as pre-1984 was about 10%. Whereas, the catastrophic drying up of the spring was probably the consequence of the anthropogenic effects. Accordingly, it requires the development of sustainable water resources management program to reduce long-term drought risks, restore the groundwater reservoir and minimize the overexploitation effects on spring discharge.

Hydrogeological mapping of heterogeneous and multi-layered ophiolitic aquifers (Mountain Prinzera, northern Apennines, Italy)

ABSTRACTA few hydrogeological studies have been carried out worldwide in peridotite aquifer systems, despite their wide distribution. The ophiolites are one of the main groundwater reservoir within the northern Apennines (Italy). This paper suggests the graphical solution to set the hydrogeological map of heterogeneous, multi-layered ophiolitic aquifers mapped on large scale (1:1600). The site investigation area is an ophiolite outcrop of the External Ligurian of the northern Apennines: the Mountain Prinzera rock complex area (44°38′30″N, 10°5′E; Parma Province, Emilia-Romagna Region). The hydrogeological characteristics of the tested aquifer system do not allow setting a hydrogeological map by applying usual graphical approaches. The hydrogeological map in such complex aquifer systems will show the classic hydrogeological data but must put in evidence above all (i) the main heterogeneities of the system, from the hydraulic point of view and (ii) the modifications of groundwater scenarios and pathways over time. The hydrogeological database of Mt Prinzera aquifer was managed in ESRI ArcGIS 10.0 software.

Combined hydrogeological and nitrate modelling to manage water resources of the Middle Soummam Aquifer, Northeast of Algeria

Water management is one of the most challenges in Algeria, a semi-arid Mediterranean country confronted to a serious water stress. The country will have to endure, beyond 2025, a situation of chronic water penury, adding an excessive pollution of the majority of groundwater reservoirs. The management of water resources by combined approach using hydrogeological model and nitrates evolution model was experimented in the Middle Soummam valley. The alluvial aquifer, offering good hydrodynamic and geometrical characteristics, is over-exploited, providing in drinking water Akbou and Tazmalt cities and irrigation perimeters. If exploitation continues at these steady paces, the depletion of the water resource and the hydrochemical imbalance will be inevitable. On the one hand, the results of hydrodynamic model, based on an increase of the water takings and simulated needs from 24.71 Mm3/year in 2015 into 39.69 Mm3/year in 2030, show a critical withdrawal. The aquifer budget expresses the inversion of flow between the wadi and the aquifer where the wadi feeds the groundwater reservoir. This hydrodynamic inversion was attributed to simulated pumping rates which increased and exceeded 100,000 m3/day, but the aquifer was partially relieved by the weight of the exploitation through Tichy Haf dam. The water management strategy adopted in this study was based on management measures promoting zones, which have been delimited between Tazmalt and Akbou, and containing important water quantities available in the axis of the valley. However, according to the depleted in isotopes of 18O and 2H, which could be explained by the influence of a paleoclimatic effect and suggested that the aquifer recharge would have largely been made under a colder climate, pumped groundwater could be old, and the implementation of new pumping sites has been studied minutely. On the other hand, the hydrogeochemical modelling allowed following nitrates concentrations in order to project their evolution. Four wells on 25 react in face to the imposed conditions in each scenario simulated until 2030, showing inertia of pollution, and confirmed after three series of tests. This inertia would be related to the hydraulic gradients and hydraulic conductivities, aquifer thickness and recharge. The low hydraulic gradients lead to a rather slow flow velocity and thus to an inertia in the dispersion of nitrates, with a mass transport weakened by the hydrodynamic conditions. It is also related to the aquifer thickness; when the aquifer is powerful (65–85 m), the stock of water would be important and allows a dilution process. The reverse is true for the simulated boreholes where the concentrations remain invariant; the aquifer is less powerful (32–37 m). Finally, the recharge effect through the rain was evoked; the aquifer is unconfined, and the rain water and pollution that reached the piezometric level can remain in position in slow hydrodynamic conditions. The methodology was demonstrated through a combination of monitoring and modelling for both water quantity and quality and the importance to use numerical models to support water resources management strategy in the Mediterranean aquifers.

Water Quality Variations in Temporal and Spatial of Dagu River Groundwater Reservoir

It has important significance for the economic and social development of Qingdao city of Dagu River Groundwater Reservoir. Introduced Dagu River groundwater reservoir area characteristics and hydrogeological conditions, analyzed temporal and spatial variation of groundwater quality in the study area. Result showed that pollution of groundwater in this area is serious and has worse trend, provide the basis for the Dagu River Basin of groundwater quality comprehensive treatment.

Antarctic subglacial groundwater: a concept paper on its measurement and potential influence on ice flow

Abstract Is groundwater abundant in Antarctica and does it modulate ice flow? Answering this question matters because ice streams flow by gliding over a wet substrate of till. Water fed to ice-stream beds thus influences ice-sheet dynamics and, potentially, sea-level rise. It is recognized that both till and the sedimentary basins from which it originates are porous and could host a reservoir of mobile groundwater that interacts with the subglacial interfacial system. According to recent numerical modelling, up to half of all water available for basal lubrication, and time lags between hydrological forcing and ice-sheet response as long as millennia, may have been overlooked in models of ice flow. Here, we review evidence in support of Antarctic groundwater and propose how it can be measured to ascertain the extent to which it modulates ice flow. We present new seismoelectric soundings of subglacial till, and magnetotelluric and transient electromagnetic forward models of subglacial groundwater reservoirs. We demonstrate that multifaceted and integrated geophysical datasets can detect, delineate and quantify the groundwater contents of subglacial sedimentary basins and, potentially, monitor groundwater exchange rates between subglacial till layers. The paper thus describes a new area of glaciological investigation and how it should progress in future.