Groundwater Table Fluctuations Research Articles

Vegetation dynamics induced by groundwater fluctuations in the lower Heihe River Basin, northwestern China

Aims Since 2000, the environmental flow controls project has been implemented in the lower Heihe River Basin, a typical arid inland river basin in northwest China, to restore the deteriorated ecological environment in this region. The aim of this study was to explore the impacts of groundwater fluctuations on vegetation dynamics. Our results can be used as a reference for water resources planning and management to maintain proper environmental flows in arid areas. Methods The location (by Global Positioning System) and depth of the monitoring wells, as well as groundwater table depth and salinity were measured in situ at each site from July to August 2009. Based on the measurements of the groundwater table depth and salinity following the implementation of environmental flow controls project (EFCP) in the lower Heihe River Basin, the groundwater fluctuations during the period from 2001 to 2009 were analyzed. Descriptive statistics and Pearson’s correlation were used to analyze the relationship between vegetation changes and groundwater table fluctuations. Additionally, the spatial distributions of the groundwater table depth and salinity were interpolated using the simple kriging method. Trend analysis was applied to the time series of integrated Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index data to identify interannual vegetation dynamics. The relationship between vegetation status and groundwater environment was investigated at different spatial scales by analyzing and comparing the time series and trends. Important Findings (i) The groundwater table and salinity increased significantly in most of the study area with spatial heterogeneity. On average, the groundwater table rose ;0.5 and 1.5 m in the upper and lower Ejina Basin, respectively, and the groundwater salinity increased across the study area by 0–4%. (ii) A notable correlation between the vegetation status and the groundwater table was revealed when the groundwater table depth fluctuated between 1.8 and 3.5 m, whereas the vegetation did not show an obvious response to groundwater table changes when the groundwater table depth was more than 5–6 m. (iii) Vegetation restoration mainly occurred in riparian areas within 500–1 000 m of from natural rivers, where the groundwater table depth varied from 2 to 4 m, and salinity was <5%, whereas vegetation degradation appeared at some locations where groundwater environment had deteriorated.

Evaluation of modified DRAINMOD in predicting groundwater table fluctuations and yield of canola in paddy fields under snowy conditions (case study: Rasht Iran)

AbstractThe computer simulation hydrologic model DRAINMOD and modified DRAINMOD (Luo et al. 2000) for cold condition was used to predict the performance of surface drainage and yield of canola as post‐rice cultivation during the wet growing season of 2004–2005 in Rasht Iran.Performance of surface drainage system treatments with 2 m spacing and 15 cm drain depth as compared with plots having no drainage (4 × 10 m2) were used to evaluate the models. Evaluation of predicted daily groundwater table depths as compared with measured values shows that the root mean square error (RMSE) was about 10.2 and 9.9 cm for DRAINMOD versus 11.0 and 11.5 for modified DRAINMOD in 2 m drain spacing and no drainage treatment respectively. Original DRAINMOD and modified DRAINMOD predictions for groundwater table depth was on average about 4 and 7% less than measured values for the surface drainage treatment and 22 and 14% greater for the no drainage treatment whereas the standard error of original DRAINMOD was 1.4 and 1.51 (cm) respectively. The average absolute deviations were 8.67 and 9.22 (cm). However by using the modified DRAINMOD these values were decreased to 1.34 1.3 8.05 and 8.19 cm respectively.Comparisons show that modifications introduced in DRAINMOD for snowy conditions improved the capability of the model to predict groundwater table fluctuations. Copyright © 2011 John Wiley &amp; Sons Ltd.

Mechanism of Soil Sodification at the Local Scale in Songnen Plain, Northeast China, as Affected by Shallow Groundwater Table

Soil sodification in Northeast China is controlled by many other factors besides groundwater level. This research aims to explore the mechanism of sodium buildup in sodic soil based on in-situ observation and laboratory analysis. Results indicate that water and sodium redistribution process on the soil surface at local scale was an additional factor leading to the rapid soil sodification development in Songnen Plain in recent decades. A field observation was conducted in a 35 × 35 m2 area. Mollisols were distributed in depressions and free of natric horizon, while Halaquepts were found on micro slopes and high flats. A natric horizon was found at a depth of 15–30 cm in high flats, with an exchangeable sodium percent (ESP) value of 70. Fluctuation of groundwater table in the freezing period was related, to some extent, to the formation and development of frozen soil. During the freezing period, groundwater table was gradually lowered as a result of the groundwater moving into the frozen layer, leading to higher moisture content therein. During the thawing period, soil moisture content in the surface layer of Mollisols showed a significant enrichment (p < 0.05) from 0.27 to 0.69 m3 m−3(over-saturated). Salt in the surface of Halaquepts enriched quickly, especially in the micro slope, by about 80%. In comparison, insignificant change was observed in Mollisols. Sodic soil should be leveled fully and adequate drainage should be utilized before farming in order to prevent soil sodification. Blocking the capillary pore channels between topsoil and subsoil by plowing before freezing season would help soil desodification in high-latitude arid and semiarid regions.

Characterization of the pre-AD 79 Roman paleosol south of Pompeii (Italy): Correlation between soil parameter values and paleo-topography

The Plinian eruption of Somma-Vesuvius AD 79 that destroyed the ancient city of Pompeii, resulted in a nearly complete burial of the Sarno River plain. Hence, to a certain extent the pre-AD 79 Roman paleo-surface and paleosols of that entire landscape were conserved. To characterize the pre-AD 79 Roman paleosol and the paleo-topographical situation south of Pompeii, ten stratigraphic core drillings were conducted along two transects stretching W–E and N–S. At five locations the drillings yielded Roman paleosols that were described, sampled and analysed for soil physical and chemical parameters. Corresponding to the present-day topography of the study area, which is flat to slightly sloping, the Roman paleo-surface appears in a similar relative paleo-topographic position. It runs nearly parallel to the modern surface at a depth of 5.50 to 6.40 m. By comparing the paleosol's properties with its position along the transects a correlation between soil parameter values and paleo-topography is revealed. The spatial distribution of paleosol characteristics is a function of soil development in relation to elevation and distance from the paleo-floodplain of the paleo-Sarno River network. This is most evident for soil thickness, soil horizonation, total organic carbon (TOC) and phosphate content and to some extent for soil texture and oxalate-extractable Si (Si ox) as a measure of allophane content. Near the paleo-Sarno River and its floodplain the Roman paleosols were 30 cm thick having an AC-profile and showed lower amounts of TOC and phosphates. In contrast, at higher elevation and longer distance from the paleo-River the paleosols were 60 cm thick, showed the development of a B-horizon, and had higher TOC and phosphate contents and partly a finer soil texture and higher amounts of Si ox. Nevertheless, all five Roman paleosols were macroscopically isotropic, i.e. they were mostly very dark gray throughout the profile. Thus, and in accordance with Al ox + 0.5Fe ox < 2%, at the time of the eruption AD 79, pedogenetically the Roman paleosol south of Pompeii is a relatively young soil. Subsequent to the eruption AD 79 at lower elevations the buried Roman paleosols have come under the influence of a seasonally fluctuating groundwater table. This caused redoximorphic features in the lower section of the AD 79 white pumice layer in terms of red Fe(III)-oxide accumulations and increased amounts of SO 4 2− in the underlying pre-AD 79 Roman paleosols.

A new perturbation solution of groundwater table fluctuations in tidal beaches

This paper modeled tide-induced groundwater flow in a vertical beach with a thin submarine outlet-capping. By implementing a perturbation method based on the Boussinesq's equation, a new approximate solution was derived for the model. Then the solution was compared with previous analytical solutions derived from the linearized Boussinesq's equation. The results showed that the error between the present and previous solutions increases with the value of the ratio of tidal amplitude to the aquifer's depth below the mean sea level and the leakage of the submarine outlet-capping.

Pore‐space CO2 dynamics in a deep, well‐aerated soil

Most studies implicitly consider soil carbon dioxide (CO2) efflux as the instantaneous soil respiration and thereby neglect possible changes in the amount of CO2 stored in the soil pore‐space. We measured the CO2 concentration profile of a well‐aerated soil continuously to evaluate the dynamics of the stored CO2 and to analyse the influence of environmental factors. For 25% of the observation period, changes in the amount of stored CO2 accounted for more than 15% of the soil‐CO2 efflux. The following factors were identified to interfere with steady‐state CO2 storage: (i) the fluctuating groundwater table altered the volume of the vadose zone, causing viscous airflow in air‐filled soil pores, (ii) atmospheric turbulence caused pressure‐pumping at the soil–atmosphere interface and (iii) intense rain greatly reduced the diffusivity of the uppermost soil layer. The friction velocity above the canopy was strongly correlated with fluctuations in the differential pressure between soil air and atmosphere, but no static pressure gradient could be detected because of the permeable nature of the soil. Unexpected short‐term declines in the soil CO2 concentration were observed during intense rainfall events. These declines were explained by the intensified CO2 saturation deficit of the infiltrating rainwater caused by the carbonate chemistry of the soil solution.

A conceptual and statistical approach for the analysis of climate impact on ground water table fluctuation patterns in cold conditions

A robust conceptual and statistical approach is presented for the study of ground water table fluctuations with precipitation and temperature as input variables. A conceptual hydrological model was developed to generate daily rainfall, snowmelt and evapotranspiration values and these values were cross-correlated with observed ground water levels to find representative time lags and significant correlations to describe the ground water system. A statistical model linking rainfall, snowmelt, evapotranspiration and ground water level was then developed and validated for an unconfined esker aquifer in boreal environment in central Finland. The model predicted very well fluctuation of ground water level and timing of the minimum and maximum water levels. A future climate change scenario for the years 2010–2039 was subsequently simulated. The simulation indicates higher ground water levels in milder winter climate. This is due to increase in winter recharge. The model provides a new tool to assess the impacts and address the uncertainties related to climate variation and change in complex ground water systems in cold regions with snow cover.

Experimental investigation of effect of tide on coastal groundwater table

In this article, a tide simulation system based on a two-way water pump technique is developed. Using this system and numerical simulations, the groundwater table fluctuation characteristics, relative over height of groundwater table, and influencing factors of over height are investigated. The experimental and numerical results indicate that the groundwater table fluctuation is of periodic, and of asymmetric. The amplitude of groundwater table fluctuations decreases with the increase of the onshore distances. There are phase lags of groundwater table fluctuations for different monitoring points. The tide can bring about remarkable over height of coastal groundwater table. The dominating factors bring about over height include the tide amplitude, aquifer thickness and tide frequency. Under experimental conditions, the relative tide amplitude over height may exceeded 50% of the maximal tide amplitude, and reach about 10% of aquifer thickness.

A fuzzy game theoretic approach for groundwater resources management: Application of Rubinstein Bargaining Theory

Developing optimal operating policies for conjunctive use of surface and groundwater resources when different stakeholders with conflicting objectives are involved, is usually a challenging task. This problem would be more complex when objectives related to surface and groundwater quality are taken into account. In this study, a new methodology is proposed to resolve the conflict of interests among water users, water supply and environmental protection agencies which are involved in a problem of conjunctive use of surface and groundwater resources. In order to develop a Pareto front among objectives, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used. To incorporate the objectives related to groundwater table fluctuations and groundwater quality, the MODFLOW and MT3D groundwater quantity and quality simulation models and the optimization model are embedded. The best non-dominated solution on the Pareto front is selected using the Rubinstein Sequential Bargaining Theory (RSBT). The Fuzzy Set Theory is also utilized to better define the utility functions of decision makers. To evaluate the efficiency of the proposed methodology, it is applied to the conjunctive use of surface and groundwater resources in the Tehran metropolitan area, Iran.

Change of magnetic properties due to fluctuations of hydrocarbon contaminated groundwater in unconsolidated sediments

Sediments affected by fluctuations of hydrocarbon contaminated groundwater were studied at a former military site. Due to remediation, groundwater table fluctuation (GWTF) extends over approximately one meter. Three cores were collected, penetrating through the GWTF zone. Magnetic parameters, sediment properties and hydrocarbon content were measured. We discovered that magnetic concentration parameters increased towards the top of the GWTF zone. Magnetite is responsible for this enhancement; rock magnetic parameters indicate that the newly formed magnetite is in a single domain rather than a superparamagnetic state. The presence of hydrocarbons is apparently essential for magnetite to form, as there is clearly less magnetic enhancement in the core, which is outside of the strongly contaminated area. From our results we conclude that the top of the fluctuation zone has the most intensive geomicrobiological activity probably responsible for magnetite formation. This finding could be relevant for developing methods for simply and quickly detecting oil spills.

Decline of groundwater table in Beijing and recognition of seismic precursory information

This paper quantitatively analyzed groundwater table fluctuations caused by groundwater overdraft, and probed into the possibility of drawing earthquake precursory information from groundwater table variations on the background of groundwater overdraft. Main effect factors of groundwater regime in Beijing region include groundwater extraction and rainfall. The decline of groundwater table was directly related to regional groundwater overdraft. Using the method of correlation analysis, the paper analyzed the relation between groundwater overdraft and groundwater level variations, with the aim of evaluating the effect of groundwater overdraft on water levels in observation wells and providing scientific basis for identifying seismic precursory information. The results indicate that the variations of groundwater level in slightly-affected zones of groundwater overdraft can contain some seismic precursory information, and it is possible to extract seismic precursory anomalies if proper mathematical methods are adopted to remove the trend component and annual period changes.

Lead Pollution of Floodplain Soils in a Historic Mining Area—Age, Distribution and Binding Forms

Historic lead mining, milling and smelting on the floodplain soils of the upper reaches of the Vils River, Eastern Bavaria, Germany has led to heavy metal contamination within the younger floodplain sediments downstream. This study aims to date the lead pollution and possible primary sources, display and quantify its spatial distribution within the Vils River floodplain in accordance to soil horizons and characterise the binding forms of lead. One hundred fifty profiles were sampled to detect total contents of heavy metals. Sequential extractions were carried out to determine the binding forms; thus, the potential of lead mobility was characterised. The contamination of the floodplain soils act as an alluvial archive, providing a stratigraphical indicator of mining activities and related sedimentation. The age of the sediments displaying the initial lead peak in the alluvial loams corresponds with sediment accumulations at the onset of the mining period and its first phase of prosperity in the sixteenth century. Enrichments of lead in the oxidic gleysols revealed that dissolved fractions of lead precipitate in the groundwater table fluctuation zone. The sequential extraction proved that lead mobility increases in the psammic and hypersceletic fluvial horizons below the flood loams due to the modest salt contents of the extractants and low pH given in these layers. Thus, the risk of the particulate transport of lead has to be extended to include the danger of potential lead solubility in ground and surface waters. Further, the polluted alluvial sediments also act as a source of contamination, leading to the grave danger of the further pollution of so far uncontaminated areas downstream, especially if the reworking and dredging of the material is allowed to occur.

Impact of recharge variations on water quality as indicated by excess air in groundwater of the Kalahari, Botswana

Groundwater is an important and often exclusive water resource in arid and semi-arid regions. The aim of the present paper was to gain insight into the processes and conditions that control the deterioration of groundwater quality in the semi-arid Kalahari of Botswana. Measurements of 3He, 4He, 20Ne, 22Ne, and of 14C of dissolved inorganic carbon (DIC) were combined with existing isotopic and hydrochemical data to investigate groundwater from the Ntane Sandstone Aquifer, which is affected by high nitrate concentrations of non-anthropogenic origin. All groundwater samples revealed neon concentrations in excess to air-saturated water, which we attributed to the addition of excess air during recharge. Neon concentrations ranged from values close to air saturation for 14C DIC rich samples (up to 80.5%MC) up to values of 90% in excess to air-saturated water for lower 14C DIC contents (2.6–61.3%MC). A strong linear correlation of excess Ne with nitrate concentrations suggests an intimate connection between groundwater quality and the processes and conditions during groundwater recharge. Low groundwater recharge rates under present-day semi-arid conditions are associated with low amounts of excess Ne and elevated nitrate concentrations. In contrast to this, higher excess Ne values in groundwater of lower 14C DIC and nitrate contents indicate that the high quality groundwater end-member presumably is related to higher groundwater table fluctuations during wetter climatic conditions in the past. We attribute the decline in groundwater quality with respect to nitrate to a decreasing rate and temporal variability of groundwater recharge, and to concurrent changes in biogeochemical activities following a transition to a drier climate during the Holocene. Under such conditions, a much stronger decrease in groundwater recharge compared to the release of nitrate from soil organic matter may result in elevated nitrate concentrations in the vadose zone and groundwater. This implies a strong impact of climate change on the transport of solutes like nitrate through the vadose zone which needs to be considered in predictions of future groundwater quality.

Estimating Land Use Impacts on Regional Scale Urban Water Balance and Groundwater Recharge

Anthropogenic activities have exerted increasingly large-scale influences on terrestrial ecological systems from the past century, primarily through agriculture; however, the impact of such changes on the hydrologic cycle is poorly understood. As one of the important land use (LU) in the coastal Dogo Plain of the Seto Inland Sea, Japan, paddy fields have been decreasing with the increase in urbanization in recent decades. As the main source of water in the Dogo Plain, groundwater plays an important role in providing people with fresh water and contributing to stream base flow. The purpose of this study is to analyze the water resource and evaluate the effect of LU change on groundwater table fluctuation in this coastal plain. Firstly, the observations of groundwater table and the investigation of water balance were carried out in this alluvial plain. Then, a distributed four-block three-layer water balance model was employed to analyze the groundwater table fluctuation with response to the change of paddy field area. Moreover, the role of paddy field in recharging groundwater in the basin has been clarified. Results show that groundwater table depends not only on rainfall and discharge from rivers, but also on irrigation water and topology of the study area. The net groundwater recharge was positive in irrigation periods whereas that in non-irrigation periods was nearly equal to zero or negative. The results of this study would be helpful to the urban development policy and land use planning decision.

Modelling wetland processes in regional applications

Wetlands represent an interface between the terrestrial environment and the surface water systems in river basins, functioning as important buffers and filters for water flow, sediments and dissolved nutrients, and pollutants. They mitigate impacts of floods, improve water quality in rivers, and reduce erosion. However, most model applications at the regional scale do not consider hydrological and eco-hydrological processes in wetlands. This study describes two approaches which allow integration of the most important wetland processes in hydrological and water quality models for regional applications. Both approaches consider water and nutrient fluxes, but they have different levels of complexity depending on data availability and objectives of the study. They are implemented in the model SWIM (Soil and Water Integrated Model). The first approach is rather simple, and can be introduced in a basin-scale ecohydrological model using two basic assumptions. This method illustrates how a very simple supply/demand approach can help to notably improve the modelling results in terms of seasonal river discharge and nutrient loads in catchments with a notable share of wetlands. The second, more advanced, approach is introduced at the level of hydrological response units (HRU) or hydrotopes, and takes into account fluctuations in groundwater table and hydrotope-related flow distances. This method allows for: (a) improving simulated water discharge in summer; (b) improving validation of nutrient-related processes; (c) estimating the impact of wetlands on water flow and nutrient load; and (d) better identification of areas in the catchment responsible for diffuse source pollution.

Evidence for Pleistocene wet aeolian dune and interdune accumulation, S. Pedro da Maceda, north‐west Portugal

AbstractOutcrops and cored/counter‐flushed boreholes in the coastal area between Espinho and Aveiro (north‐west Portugal) were investigated to reconstruct the changing patterns of sedimentation during the Late Pleistocene–Holocene. To obtain a common comparison basis, the grain‐size data from outcrop and borehole samples were analysed. The outcrops and the cored parts of the boreholes were dated by radiocarbon and optically stimulated luminescence. The results show that, on top of pebble‐rich beds of fluvial origin, a wet aeolian dune and interdune environment was active during the later part of the Pleistocene, turning to dry aeolian at the transition to the Holocene. The data indicate also that aeolian accumulation was controlled by vegetation changes (climate) and groundwater table fluctuations. During the Holocene, a podzol formed on the Pleistocene dunes and extensive vegetation precluded major aeolian accumulations. Remobilization of sand started again because of human deforestation and – last but not least – the Little Ice Age.

A Conflict-Resolution Model for the Conjunctive Use of Surface and Groundwater Resources that Considers Water-Quality Issues: A Case Study

The conjunctive use of surface and groundwater resources is one alternative for optimal use of available water resources in arid and semiarid regions. The optimization models proposed for conjunctive water allocation are often complicated, nonlinear, and computationally intensive, especially when different stakeholders are involved that have conflicting interests. In this article, a new conflict-resolution methodology developed for the conjunctive use of surface and groundwater resources using Nondominated Sorting Genetic Algorithm II (NSGA-II) and Young Conflict-Resolution Theory (YCRT) is presented. The proposed model is applied to the Tehran aquifer in the Tehran metropolitan area of Iran. Stakeholders in the study area have conflicting interests related to water supply with acceptable quality, pumping costs, groundwater quality, and groundwater table fluctuations. In the proposed methodology, MODFLOW and MT3D groundwater quantity and quality simulation models are linked with the NSGA-II optimization model to develop Pareto fronts among the objectives. The best solutions on the Pareto fronts are then selected using YCRT. The results of the proposed model show the significance of applying an integrated conflict-resolution approach to conjunctive use of surface and groundwater resources in the study area.

Application of MASW technology to identification of tidal flat stratigraphy and its geoenvironmental interpretation

Intertidal flats are key elements in marine environments; they consist of regions with rich bioactivity and also contribute to water purification. Recently, it has been demonstrated that benthic activities in intertidal flats are closely related to geoenvironmental characteristics. The purpose of this study is to investigate the tidal flat stratigraphy which should be strongly affected by the geoenvironmental characteristics. We examined the shear wave velocity/stiffness structures of intertidal flats by a surface wave method called the multichannel analysis of surface waves (MASW) in order to identify and describe the cross-shore and alongshore tidal flat stratigraphy. Field surveys were carried out on a natural sandflat, natural mudflat, and artificial layered sand–mud flat during the spring tides in summer when these flats were exposed. The MASW has proved to be a very useful method to effectively survey the stratigraphy of various types of intertidal flats. This method is widely acceptable to nature because it does not have any harmful impacts. The tidal flat stratigraphy obtained by the MASW was consistent with the morphological soil structures that manifested themselves under relevant geoenvironmental dynamics. In the sandflat, the formation of stratigraphy obtained by the MASW (as distributions of the shear wave velocity/stiffness) and by soil sampling and physical soil tests (as distributions of the void ratio) can be attributed to the cyclic elastoplastic contraction of the soils that are subjected to various suction dynamics under tide-induced groundwater table fluctuations. In the mudflat, although a variation in the void structure was observed in association with grain size distributions, the soil stiffness was extremely homogeneous because suction did not occur in the soil. In the small-scale artificial layered sand–mud flat, which contained dredged muddy soil with a sand capping, the artificially layered tidal flat stratigraphy was clearly identified by the MASW. The groundwater table dynamics were equivalent to those in the natural large-scale sandflat, indicating that the geoenvironmental characteristics were successfully recreated, even though it had a layered sand–mud stratigraphy.

Sustainability of rice‐dominated cropping system in the Hirakud canal command, Orissa, India

AbstractThe present rice‐based cropping system in the canal command of the Hirakud irrigation project, Orissa (India), is under severe threat due to waterlogging in the monsoon season and acute irrigation water deficit in the non‐monsoon season. Estimation of irrigation water supply and demand reveals that at the present level of cropping, canal water availability during the monsoon is just sufficient to meet the irrigation requirements of crops at only 10% probability of exceedance. During the non‐monsoon season, irrigation water requirement at 10% probability of exceedance exceeds canal water availability by more than 1050 million m3. Groundwater table fluctuation study reveals that during the monsoon more than 90% of the command area remains and during the non‐monsoon, in more than 40% of the area the groundwater table remains within 2–4 m of the surface. Hence there is ample scope for groundwater development. However, even at the permissible limit of groundwater development, the annual water deficit is more than 1000 million m3 at 50% probability of exceedance of irrigation water demand, which can only be mitigated by replacing the existing non‐monsoon rice by other crops with low water requirements as cultivated in the command. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Groundwater and climate dynamics derived from noble gas, 14C, and stable isotope data

Research Article| May 01, 2008 Groundwater and climate dynamics derived from noble gas, 14C, and stable isotope data Stephan Klump; Stephan Klump 1Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland and Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland Present address: EBA Engineering Consultants, Ltd., Calcite Business Centre, Unit 6, 151 Industrial Road, Whitehorse, Yukon Y1A 2V3, Canada; E-mailsklump@eba.ca. Search for other works by this author on: GSW Google Scholar Tim Grundl; Tim Grundl 2Department of Geosciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin 53201, USA Search for other works by this author on: GSW Google Scholar Roland Purtschert; Roland Purtschert 3Physics Institute, University of Berne, 3012 Berne, Switzerland Search for other works by this author on: GSW Google Scholar Rolf Kipfer Rolf Kipfer 4Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland and Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, 8092 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Stephan Klump Present address: EBA Engineering Consultants, Ltd., Calcite Business Centre, Unit 6, 151 Industrial Road, Whitehorse, Yukon Y1A 2V3, Canada; E-mailsklump@eba.ca. 1Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland and Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland Tim Grundl 2Department of Geosciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin 53201, USA Roland Purtschert 3Physics Institute, University of Berne, 3012 Berne, Switzerland Rolf Kipfer 4Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland and Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, 8092 Zurich, Switzerland Publisher: Geological Society of America Received: 13 Nov 2007 Revision Received: 24 Jan 2008 Accepted: 25 Jan 2008 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2008 Geological Society of America Geology (2008) 36 (5): 395–398. https://doi.org/10.1130/G24604A.1 Article history Received: 13 Nov 2007 Revision Received: 24 Jan 2008 Accepted: 25 Jan 2008 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Stephan Klump, Tim Grundl, Roland Purtschert, Rolf Kipfer; Groundwater and climate dynamics derived from noble gas, 14C, and stable isotope data. Geology 2008;; 36 (5): 395–398. doi: https://doi.org/10.1130/G24604A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Noble gas data in conjunction with stable isotopes and 14C ages of groundwater samples from southeastern Wisconsin, USA, indicate a soil cooling of at least 6.5–7 °C during the last glacial period compared with modern soil temperatures. Because stable isotope and excess Ne data indicate that none of the samples contains any significant portions of glacial meltwater, samples with 14C ages between 12 and 26 ka B.P., which is the time when the study area was ice covered, most likely infiltrated during short periods of ice retreat or represent recharge containing a significant proportion of precipitation rather than subglacial meltwater recharge. Further, all samples except for those recharged before the last glacial period show a strong correlation between noble gas temperature and δ18O. By contrast, δ18O values of samples older than ca. 28 ka B.P. are too heavy with respect to their noble gas temperatures. This might be due to a stronger influence of an isotopically enriched moisture source from the Gulf of Mexico. The amount of excess air, which is closely linked to the magnitude of groundwater table fluctuations, increases shortly before and at the beginning of the last glacial period, suggesting that recharge dynamics changed considerably during that time period. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.