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The long-term settlement of calcareous sand foundations caused by daily periodic fluctuations has become a significant geological hazard, but effective monitoring tools to capture the deformation profiles are still rarely reported. In this study, a laboratory model test and an in situ monitoring test were conducted. An optical frequency domain reflectometer (OFDR) with high spatial resolution (1 mm) and high accuracy (±1 μe) was used to record the soil strain responses to groundwater table and varied loads. The results indicated that the fiber-optic measurements can accurately locate the swelling and compressive zones. During the loading process, the interlock between calcareous sand particles was detected, which increased the internal friction angle of soil. The foundation deformation above the sliding surface was dominated by compression, and the soil was continuously compressed beneath the sliding surface. After 26-48 h, calcareous sand swelling occurred gradually above the water table, which was primarily dependent on capillary water. The swelling of the soil beneath the groundwater table was completed rapidly within less than 2 h. When the groundwater table and load remain constant, the compression creep behavior can be described by the Yasong-Wang model with R2 = 0.993. The daily periodically varying in situ deformation of calcareous sand primarily occurs between the highest and lowest groundwater tables, i.e. 4.2–6.2 m deep. The tuff interlayers with poor water absorption capacity do not swell or compress, but they produce compressive strain under the influence of deformed calcareous sand layers.

Mountain headwater streams are important freshwater sources, but they are mostly intermittent and highly susceptible to climate change. This paper examines the sustainability of augmented freshwater availability in mountain headwater streams for water supply under baseline and future climate change scenarios using an integrated modeling approach. The climate change data in the 2040s (2030–2059), under Representative Concentration Pathway 4.5 and 8.5 scenarios, were downscaled for the impact assessment. In the region, climate change raises the average precipitation by 5–7% and the temperature by 13–15% in the 2040s. SWAT–MODFLOW model, integrating Soil and Water Assessment Tool (SWAT2012) and finite-difference Modular Groundwater Flow (MODFLOW) models in a single package, was used to assess the water balance. Results show that extracting a minimum of 16.2 m3/day from the sand storage and 30 m3/day from the aquifer was possible without affecting the groundwater table and water yield. The average annual catchment recharge was 6% of the precipitation under the baseline simulation. Climate change is projected to reduce the average water yield and groundwater recharge by 26% and 19%, respectively. However, the water supply-demand is significantly small compared to the exploitable rate of water in the area. This study was based on limited data, and therefore the findings need to be interpreted with caution, though the model output was validated using satellite products. Construction of a series of sand dams is suggested to maximize the benefit under the potential climate change and water supply-demand increase.

Several reclamation approaches were developed in the last decades to control acid mine drainage from tailings storage facilities, including the monolayer cover combined with an elevated water table. Its performance is dependent on water table elevation and tailings saturation and is directly affected by climatic conditions; therefore, climate change needs to be taken into account to design resilient reclamation systems. The objective of this research was to evaluate three approaches to simulate climate change and compare the impact on reclamation performance up to year 2100. Numerical simulations were calibrated using experimental field data, and future weather conditions were established based on three climate change scenarios adapted for local conditions. Results showed that the projected impact of climate change varied depending on the approach used. Simpler and more conservative approaches indicated that reclamation would eventually fail following an increase of droughts during future summers. However, 80 year simulations showed that reclamation failures (evaluated as oxygen flux) could be limited to a few isolated summers and that a well-designed monolayer cover with elevated water table appeared to remain efficient in the long term. Overall, the probability to exceed the oxygen flux target of 1 mol/m2/year did not exceed 2% for the simulated conditions.

Drought tolerance research using large plant populations may benefit from high-throughput phenotyping systems which allow for accurate measurement of daily single-plant water use. In this work, we identify and optimize a soil mix as part of a passive, bottom-watered pot culture system for soybean (Glycine max (L.) Merr.), which can induce varying but consistent levels of drought stress via adjustment of pot-specific water tables. The soil media within the pot wicks water upwards to maintain soil moisture equilibrium through the rooting column over an entire growth cycle, even as the roots take up water. Plants remained healthy throughout the growth cycle and treatments produce significant differences in water use, growth and yield traits. This system can also be adapted to large-population phenotypic screenings, including Genome-Wide Association Studies. Such a system would greatly improve the feasibility of measuring growth and yield traits in large plant populations grown to maturity. Natural Sciences and Engineering Research Council of Canada, Reference #401221245

The extent to which groundwater flow affects drainage density and erosion has long been debated but is still uncertain. Here, I present a new hybrid analytical and numerical model that simulates groundwater flow, overland flow, hillslope erosion and stream incision. The model is used to explore the relation between groundwater flow and the incision and persistence of streams for a set of parameters that represent average humid climate conditions. The results show that transmissivity and groundwater flow exert a strong control on drainage density. High transmissivity results in low drainage density and high incision rates (and vice versa), with drainage density varying roughly linearly with transmissivity. The model evolves by a process that is defined here as groundwater capture, whereby streams with a higher rate of incision draw the water table below neighbouring streams, which subsequently run dry and stop incising. This process is less efficient in models with low transmissivity due to the association between low transmissivity and high water table gradients. A comparison of different parameters shows that drainage density is most sensitive to transmissivity, followed by parameters that govern the initial slope and base level. The results agree with field data that show a negative correlation between transmissivity and drainage density. These results imply that permeability and transmissivity exert a strong control on drainage density, stream incision and landscape evolution. Thus, models of landscape evolution may need to explicitly include groundwater flow.

Present work is a case study of rainwater harvesting needs and the measures being adopted for the northern region of Haryana, India, covering the districts of Rewari and Mahendergarh. The study was necessitated following the notification by Haryana Urban Development Authority to make rainwater harvesting mandatory for its urban estates. As per the notification: “each individual plot holder having a rooftop area of 100 sq. m. or more, is required to provide for suitable rainwater harvesting measures.” Keeping in view the available soil strata, average rainfall, rainfall intensity, social acceptability etc., a plan has been drafted to comprehensively utilize the rainfall water falling in the campus of Central University of Haryana, Mahendergarh, a campus of around 488 acres of area. Land area requirement for different suggested modes is likely to be a very small percentage of the total catchment’s area. In the first phase, ground water recharge structures for School of Engineering and Technology are suggested. Major objective of the study is to provide rainwater harvesting structures so that ground water storage is enhanced to an extent that it would suffice the drinking water needs of students and faculties residing in the campus. Another objective of the study is that these recharge structures will serve as models and infuse confidence in people to follow the good work initiated by the Haryana Urban Development Authority.

Since unsaturated soil conditions are normally experienced above the groundwater table, most treated or stabilised soils for roadworks, earth dams’ embankments, landfill sites, hydraulic barriers etc. could be regarded as existing in this region. The soil–water characteristic (or retention) curve (SWCC) is a useful conceptual tool by which an evaluation of unsaturated soil's property functions and corresponding macro-scale behaviour (strength, volume change, hydraulic conductivity, fluid flow, diffusivity, etc.) can be carried out. Hence, an examination of some of the various factors that could affect the hydraulic or water retention property of the stabilised soil is very vital both for laboratory studies and field practice. However, a thorough assessment of the water retention behaviour of stabilised soils can be understandably limited sometimes. This could be partly due to some of the perculiar conditions associated with soil preparation methods, soil type, soil-stabiliser mix proportion used, curing conditions, method of compaction, durability assessment modalities and other logistical issues surrounding either laboratory instrumentation or in-situ application. This article presents a critical and comprehensive review of these factors on the stabilised soil’s water retention behaviour and also provides a systematic understanding of the mechanisms of stabilisation occurring at the micro- and macro-mechanical levels. Recommendations are also made to stimulate further discussions on the synthesis of SWCC of stabilised soils vis-a-vis factors influencing them with possible interpreted engineering behaviours such as shear strength and soil consolidation.

iWetland is a community science wetland water level monitoring platform developed by the McMaster Ecohydrology Lab and tested from 2016 to 2019 in wetlands located east of Georgian Bay, Ontario, Canada. The goal of iWetland is to engage community members in wetland science while collecting data to better understand the spatiotemporal variability in water level patterns of wetlands. We installed 24 iWetland water level monitoring stations in popular hiking and camping areas where visitors can text the water level of the wetland to an online database that automatically collates the data. Here, we share our approach for developing the iWetland community science platform and its importance for monitoring all types of wetland ecosystems. From 2016 through 2019, almost 2,000 individuals recorded more than 2,600 water table measurements. The iWetland platform successfully collected accurate water table data for 24 wetlands. We discuss the successes and shortcomings of the community science platform with respect to data collection, community engagement, and participation. We found that forming mutually beneficial partnerships with community groups paired with strong outreach presence were key to the success of this community science platform. Finally, we recommend that those interested in adopting the iWetland platform in their community partner with community groups, recognize participant contributions, identify accessible sites, and host outreach activities.

Rapid urbanization, coupled with land use land cover changes (LULC), has caused stress on freshwater resources around the globe. As in the case of Islamabad, the capital of Pakistan, the population has increased significantly, creating a deficit of natural resources and affecting the environment adversely. Therefore, the purpose of this study is to examine the effects of urbanization and LULC on the decline of the static water table in Islamabad. It also seeks to analyze water policy issues in order to achieve sustainable water resource development. The excessive pumping of the existing groundwater has exceeded the safe limit, which is justified by the constantly growing population. However, the changes in the LULC of the study area have turned many green pastures into barren land. Our research data were obtained from the Capital Development Authority (CDA), Pakistan Meteorological Department (PMD), and Landsat Satellite images. After analyzing PMD and CDA data for the last 20 years (2000–2020), the results were interpreted using Arc GIS. It has been observed that the Normalized Difference Vegetation Index (NDVI) value increases as the Land Surface Temperature (LST) decreases. Therefore, the overall observation is a decreasing trend in Islamabad temperatures due to the increased vegetation in the study area during the period of 2000–2020. It was observed that there has been a considerable drop in water levels due to over-pumping in a few areas. It is primarily associated with the increasing population of the capital in the last 2 decades. This study uses a survey to explore the potential locations for check dams to enhance and recharge the groundwater aquifers in the capital, Islamabad. It suggests catchment areas throughout the Margalla Hills along with different localities, such as Rumli Village, Trail 5, and Shahdara. Validerad;2023;Nivå 2;2023-02-15 (hanlid)

La práctica empresarial se realizó en la finca Santa Helena perteneciente a la empresa GRUPO 20 S.A, ubicada en el municipio de Carepa, Antioquia. El objetivo de la práctica empresarial fue monitorear el sistema de drenaje de la finca, llevar un control de los niveles freáticos y evaluar las labores de protección y cosecha de la fruta. Para ello, se tomaron datos semanalmente, y se realizaron mediciones utilizando implementos de campo (flexómetro, GPS), y formatos de toma de datos suministrados por la empresa. Se identificó las principales falencias que presentaba cada caso por lo que se logró llevar un seguimiento y control de las mismas, así mismo, dar posibles soluciones a las problemáticas de la finca. 0. INTRODUCCIÓN .............................................................................................. 15 1. RESEÑA HISTÓRICA DE LA EMPRESA .................................................... 18 1.1. Misión ................................................................................................................. 19 1.2. Visión .................................................................................................................. 19 1.3. Políticas de desarrollo ...................................................................................... 19 2. OBJETIVOS....................................................................................................... 20 2.1. OBJETIVO GENERAL .................................................................................... 20 2.2. OBJETIVOS ESPECÍFICOS .......................................................................... 20 3. REVISION DE LITERATURA ......................................................................... 21 3.1. Aspectos edafoclimaticos ................................................................................ 21 3.2. Establecimiento del cultivo .............................................................................. 22 3.2.1. Selección del terreno ................................................................................ 22 3.2.2. Adecuación del terreno ............................................................................ 23 3.2.3. Distribución de canales y drenajes ......................................................... 24 3.3. Medición del nivel freático ............................................................................... 25 3.4. Labores de protección de fruta ....................................................................... 26 3.4.1. Amarre ........................................................................................................ 27 3.4.2. Embolse e identificación .......................................................................... 27 3.4.3. Desflore ....................................................................................................... 28 3.4.4. Desmane y desbacote .............................................................................. 28 3.4.5. Despeje de racimo (Deshoje) .................................................................. 28 3.4.6. Guantelete o yumbolon ............................................................................ 28 3.4.7. Desvío de hijos o racimos ........................................................................ 29 3.4.8. Reamarre .................................................................................................... 29 3.5. Labores de cosecha ......................................................................................... 29 4. ACTIVIDADES REALIZADAS ........................................................................ 30 4.1. Capacitaciones .................................................................................................. 30 4.2. Inventario del drenaje superficial y población de plantas .......................... 31 4.3. Lectura del nivel freático .................................................................................. 37 4.4. Evaluación de labores de protección de fruta .............................................. 38 4.5. Evaluación de cosecha .................................................................................... 42 5. CONCLUSIONES ............................................................................................. 48 6. RECOMENDACIONES .................................................................................... 49 7. BIBLIOGRAFÍA ................................................................................................. 50 8. ANEXOS ............................................................................................................ 52 Pregrado Ingeniero(a) Agronómico(a) Práctica Empresarial

Ecohydrological studies in tropical peatland have mostly focused on a small number of non-native commercial species. However, studies of native species are urgently needed as they are considered to be a possible solution in the restoration of millions of hectares of degraded tropical peatlands. We investigated peatland species on Padang Island, Indonesia, to assess their responses to changing environmental factors, particularly the high fluctuation of the water table due to intensive peatland draining. We monitored the sap-flux velocity and radial growth of six trees (four native and one non-native peatland species) in high temporal resolution using sap-flux meters and dendrometers up to seven months. Monitoring also included hydrological and micrometeorological parameters. We found that sap-flux velocity in the monitored species was mainly controlled by air vapor pressure deficits, photosynthetic active radiation, and to some extent, by wind speed and water-table depth. We also observed a species-specific correlation between daily sap-flux velocity and daily radial growth. Non-native Acacia crassicarpa had up to twice the radial growth of native species. This growth of non-native species was significantly higher at a shallow water-table depth, while native species did not show the same relationship. The interaction between water-table depth, sap-flux velocity, and radial growth in daily timescale was not straightforward, presumably because of the complex carbon-allocation mechanism in trees.

Sheet pipe is a type of perforated pipe used for drainage designed initially for drainage but has the potential for sub-surface irrigation. The objectives of this study were to experiment and observe the performance of the sub-surface irrigation control system with sheet pipe. This investigation covered the observation of water table control and its effect on soil moisture. The detailed process of water flow during the setting of the water table was numerically modeled in 2 dimensions to observe the distribution of soil moisture, soil pressure, and flux. The results showed that the system successfully controlled the water table at the desired level in the experiment. The developed two-dimensional numerical simulation showed the distribution of soil moisture in the model center as a response to the water table increase, represented by the variable head. The soil wetting advances toward soil surface driven by the water table, which was increased gradually and reached saturation at the height of water table setpoint.

Soil-leaf hydraulic conductance determines canopy-atmosphere coupling in vegetation models, but is typically derived from ex-situ measurements of stem segments and soil samples. Using a novel approach we derive robust in-situ estimates for whole tree conductance (ktree ), 'functional' soil conductance (ksoil ), and 'system' conductance (ksystem , water table to canopy), at two climatically different tropical rainforest sites. Hydraulic 'functional rooting depth', determined for each tree using profiles of soil water potential (Ψsoil ) and sap flux data, enabled a robust determination of ktree and ksoil . ktree was compared across species, size classes, seasons, height above nearest drainage (HAND), two field sites, and to alternative representations of ktree ; ksoil was analysed with respect to variations in site, season and HAND. Key results: i) ktree was lower and changed seasonally at the site with higher vapour pressure deficit (VPD) and rainfall, ii) ktree differed little across species but scaled with tree circumference, iii) rsoil (1/ksoil ) ranged from 0 in wet season to 10x less than rtree (1/ktree ) in the dry season. Conclusions VPD and not rainfall may influence plot-level k; leaf water potentials and sap flux can be used to determine ktree , ksoil and ksystem ; Ψsoil profiles can provide mechanistic insights into ecosystem-level water fluxes.

Restoration and water table control on peatlands to limit fire risk are national priorities in Indonesia. The present study was initiated at Padang Island, Sumatra, to increase understanding on peatland hydrology in the tropic. At the pilot site, water table and precipitation were monitored at different stations. The results show variation in water table depths (WTDs) over time and space due to spatial and temporal variability in rain intensity and drainage networks. In part of the island, large-scale drainage for plantations led to deep WTD (−1.8 m) and high WTD recession rates (up to 3.5 cm/day). Around villages, farm-scale drainages had a smaller impact with a lower recession rate (up to 1.8 cm/day) and shallow WTD, typically below −0.4 m, the threshold for sustainable peatland management in Indonesia. The recession rates levelled off at 1.0 cm/day near the drained forest/plantation and at 0.5 cm/day near the farm. Deeper layers had much lower specific yield (Sy), 0.1 at −1.5 m depth, compared with top peat soils with Sy up to 0.3. Proximity to drainages extended discharge flow to deeper layers. The results highlighted the severity of peatland drainage impact on most coastal zones of Padang Island, which have intensive drainage networks. HIGHLIGHTS High spatial and temporal variability of water table was observed in Padang Island.; The variability was partially driven by variation in land use and farm drainages.; Recession rate near pulp plantations remained high (0.01 m/day) at −1.5 m depth.

Alpine wetlands are hotspots of carbon (C) storage and methane emission, and they could be key contributors to global warming. In recent years, rapid warming has lowered the water table in alpine wetlands on the Tibetan Plateau, concurrent with intensified nitrogen (N) deposition via anthropogenic activities. We carried out a field experiment to investigate the ecological impacts of these two factors on soil bacterial and functional communities, which are essential drivers of greenhouse gas emissions. Nitrogen amendment alone decreased the phylogenetic alpha-diversity of bacterial communities which could be offset by lowered water table. In contrast, microbial functional alpha-diversity, revealed by a high-throughput microarray, remained unchanged. Both bacterial and functional beta-diversity responded to lowered water table, but only bacterial community responded to N amendment. The alpha-Proteobacteria, beta-Proteobacteria, and Bacteroidetes were the major responsive bacterial lineages, and C degradation, methanogenesis, alkaline shock, and phosphorus oxidation were the major responsive functional processes. Partitioning analysis revealed that N amendment changed bacterial community structure mainly via species loss processes but did not affect bacterial functional communities, with soil pH and ammonium as the key factors influencing changes in bacterial community structure. Conversely, lowered water table altered bacterial and functional communities through species substitution processes linked to soil pH and soil moisture. According to our results, the response mechanisms of microbial communities to lowered water table and N amendment are fundamentally different in alpine wetlands.

Since 2016 we have studied the largest interdunal wetlands/slack lying within a deflated parabolic dune east of Lake Michigan. Geologic cross-sections show ∼ 15 m of sand and gravel beneath the dunes, creating an aquifer hydraulically connecting Lake Michigan-Huron (MH) with the water table/shallow groundwater influencing the slack. Lake Michigan-Huron (MH) water levels have risen ∼ 1 m from 2016 to 2020, increasing water levels within and around the slack ∼ 1 m. Color-infrared images and vegetation quadrat sampling show water appearing, then significantly expanding with the main slack and upland/dune vegetation transitioning to wetland vegetation in response to this rise. Monitoring well data show slack water levels rise in spring as Lake MH rises. Levels drop as the growing season begins while Lake MH continues to rise through summer. Short-term slack water level increases occur due to local rain events, but significant water level declines follow due to evapotranspiration. Slack water levels begin to rise again in late summer and into fall as the end of the growing season arrives, evapotranspiration decreases, and heavier, more frequent rain events occur. Together, these factors push slack water levels to their highest point of the year while Lake MH levels are decreasing. In late fall–winter, slack water levels drop in concert with Lake MH levels. Climate change effects, increased transpiration from higher temperatures, summer drought, and greater variability in lake level fluctuations, may make it more difficult to maintain wet growing conditions for hydrophytic vegetation. Hence, climate change poses risks to the existence of this imperiled ecosystem.

We address the significant knowledge gap for groundwater pollution in Africa methods by assessing groundwater pollution risk at the African scale. To do so, we compiled the most recent continental-scale information on soil, land use, geology, hydrogeology, and topography in a Geographical Information System at the resolution of 15 × 15 km and the 1:60 000 000 scale. We produced a vulnerability map by using the generic DRASTIC vulnerability indicator. This map revealed that groundwater is highly vulnerable in Central and West Africa groundwater basins, where the water table is shallow. In addition, very low vulnerability classes are found in the large sedimentary basins of Africa deserts where groundwater is situated in very deep aquifers. The generic groundwater pollution risk map is obtained by overlaying the DRASTIC vulnerability indicator with current land use. The northern, central, and western parts of the African continent are dominated by high vulnerability classes and very strongly related to water table depths and the development of agricultural activities. Given the availability of data, we concentrate first on nitrate vulnerability mapping. To this end, groundwater nitrate contamination data are compiled in literature using meta-analysis technic and used to calibrate as well linear and nonlinear statistical models; the latter performing much better as compared to simple linear statistical models. This study will help to raise awareness of the manager's International Basin Authorities or Transboundary Basin Organizations in Africa and in particular on transboundary groundwater pollution issues.

Forested wetlands with high water tables are sensitive to disruption from harvesting yet support commercially desired tree species like northern white-cedar. Winter harvest was conducted in Maine, ...

Floodplains cover only 6% of the Earth’s surface. Connectivity occurs in multidirectional patterns in riverbeds, throughout both the drainage paths of the tributaries and the areas contiguous to the riverbed. This study discusses the variations in the levels of the water table as a component of a spatiotemporal representation for evaluating the importance of floodplains as hydric regulatory elements, and the application of this knowledge for developing techniques for the renaturalization of water functions to produce ecosystem services. We measured the variation in the water table level in a floodplain of the Paraiba do Sul River (southeastern Brazil), whose 77 floodplains occupy only 3.87% of the basin and present a high potential for the renaturalization of their water functions. The litho-structural control point (LSCP) is situated in the river channel and mark the end of the floodplain. Areas near the LSCP remain continually saturated, storing water and contributing to dry-season hydrographs. Areas up to 4400 m away from the LSCP perform hydric regulation, storing water from floods of the riverbed and reducing its flow downstream. Areas up to 7500 m away from the LSCP have an increased absorption potential. These three areas operate differently and integrally in absorbing floodwaters and recharging the water table, influencing the increase in minimum flows in the riverbed. The understanding of the functions of these sectors enables the design of objective measures that safeguard and increase the likelihood of the renaturalization of the hydrological functions of floodplains.

Run-off water and groundwater carried out the most important cycle between flora and fauna. The Rushikulya river basin is a particular region where one can study the profound behaviour of groundwater, river run-off and seawater. The river system influences the population in Ganjam District. The flow system of the river basin is profoundly affected by its topography and regional tectonics scenario. Understanding the topographical influence, morphometry tools subsequently play vital role and provide knowledge about river basin. Here in this study, the depleting groundwater condition in Rushikulya river basin is correlated with morphometric indices and used to assert its influence. Periodic groundwater level data set is used to assert the condition in the region from 1995 to 2015. The condition of groundwater table and recharge zone is traced with the help of GIS tools. Further recharge zones and depleting zones for groundwater are taken into consideration in the study. The influence of salty water of the Bay of Bengal is also considered in the study to state the contamination in groundwater. This study shows huge depletion in groundwater conditions during 1995–2015 in the western and northern regions of the basin. The eastern part shows depletion in groundwater during 1995–2005 but enhancement during 2010–2015, which may have influence of transgressing seawater. The pre-monsoon and post-monsoon groundwater conditions show Rushikulya river channels are influencing groundwater recharge. Due to this Aska region gets a better groundwater recharge condition as it is situated near the tri-junction of tributaries. Besides, the impact of land use and land cover also played a vital role with the inducements of groundwater depletion within the basin.

Groundwater is one of the most valuable water resources in the world in terms of quantity and quality. Therefore, their protection as an important issue should be considered by the operating managers. Among the types of existing groundwater aquifers, the coastal aquifers need more protection because they could be contaminated by salt in the result of seawater intrusion. Their protection is a priority based on an optimal and comprehensive management model. Increasement of demands in these areas, especially in recent years, requires sustainable and optimal management as one of the main objectives for long-term operation in the future. In order to meet this purpose, a simulation-optimization model of Bandargaz-Nokandeh coastal groundwater system that located in the north of Iran was proposed by the employment of the Groundwater Modeling System (GMS) numerical model and the Non-Dominate Sorting Genetic Algorithm-II (NSGA-II) multi-objective evolutionary optimization algorithm. In this study based on the quantitative simulated groundwater model; two managerial issues have been examined; including the control of water-table drawdown and sustainability of extraction from the wells in this aquifer. By combining these two models and implementing them, optimal withdrawal scenarios which examines different aspects of the study objectives, have been extracted. Regarding the decision-making methods of Simple Additive Weighting (SAW), Gray Relational Analysis (GRA), and Berda Aggregation method (BAM), the best scenario was determined among the points located on the optimal trade-off curve. The results show that implementations of management strategies to create a sustainable development of the Bandargaz-Nokandeh coastal aquifer, has led to a 48.45 percent decrease in water withdrawal. Also, the comparison of the groundwater table level (GWTL) under the two existing and optimal operating conditions shows a 29.54% reduction (monthly average) in the area of aquifer that contain drawdown in the GWTL. This reduction varies from 1.43% in October 2011 to 59.22% in September 2012. Based on this optimal operation policy, the consequences of excessive withdrawal, and more than the natural capacity of the aquifer, could be compensated. Besides that, in order to the sustainable development of the aquifer can be controlled the amount of water extracted from operation wells.

A combined survey including infrared thermography (IRT) and field-laboratory tests were conducted to analyze the thermal responses and thermal properties of loess on a landslide-prone loess slope in the Heifangtai terrace in Northwest China aiming at preliminarily demonstrating the potential of IRT as a complementary technique to the investigation of irrigation-induced loess landslides. Multitemporal thermographic surveys corresponding to various solar radiation intensities during the afternoon were carried out on the landslide-prone loess slope. Accordingly, the spatiotemporal distribution of the thermal responses within the observed slope surface was analyzed qualitatively and quantitatively. Meanwhile, field and laboratory investigations were also performed on the thermal properties of different landslide materials. The results indicate that loess, a landslide-prone deposit that usually has a relatively high water content, exhibits different thermal properties and anomalies, including a lower surface temperature and greater thermal inertia, compared to surrounding zones without landslides. The groundwater table and corresponding seepage line could also be obtained by determining the potential boundary between the thermal response distribution of landslide scarps and that of saturated deposits in the presence of landslides. The results of these investigations are expected to provide insight for future endeavors combining infrared thermography with other efficient survey methodologies (e.g., InSAR, which can monitor the active displacement of a loess slope) to evaluate the activity of this kind of excessive irrigation-induced loess landslide.

Flownets, geo-electric layers construction and groundwater exploration analysis was investigated in the eastern and Western parts of Ilorin of Southwestern Nigeria. Apata-Yakuba, Eleko-yangan, Tepatan, Oke-Andi at the Eastern part and Akamo, Idi-Araba in the Western part of Ilorin were surveyed to depict the exact locations for potential future groundwater exploration. A preliminary step to collect lithologs of wells from the records of Nigeria Hydrological Services Agency used 35 water samples taken from hand dug wells and boreholes. Static water levels, total depth and coordinates of hand dug wells were measured using tape and GPS respectively. The Static water level (below ground surface and above sea level) values and their coordinates were processed using IPWIN resist software to generate the water level locations on topographical contour maps and the groundwater flow net of the study area. Result reflects the presence of crystalline rocks consisting of migmatite gneiss, granite gneiss, quartzite and granite. Analysis and interpretation of flownet shows ascending equipotential lines at the Eastern part indicating an easy groundwater movement, and divergent equipotential lines at the Western part indicating difficulty in water movement in the study area. The static water levels values together with the corresponding coordinates were superimposed on the geological map of the study area. This research reveals the water table is very close to ground surface in Oyun, Oke-Andi resulting into digging of shallow wells by the dwellers of the area. Water table is also far away from the surface in places Tepatan, Apata-Yakuba among others

Recent advancements in computational efficiency and Earth system modeling have awarded hydrologists with increasingly high-resolution models of terrestrial hydrology, which are paramount to understanding and predicting complex fluxes of moisture and energy. Continental-scale hydrologic simulations are, in particular, of interest to the hydrologic community for numerous societal, scientific, and operational benefits. The coupled hydrology–land surface model ParFlow–CLM configured over the continental United States (PFCONUS) has been employed in previous literature to study scale-dependent connections between water table depth, topography, recharge, and evapotranspiration, as well as to explore impacts of anthropogenic aquifer depletion to the water and energy balance. These studies have allowed for an unprecedented process-based understanding of the continental water cycle at high resolution. Here, we provide the most comprehensive evaluation of PFCONUS version 1.0 (PFCONUSv1) performance to date by comparing numerous modeled water balance components with thousands of in situ observations and several remote sensing products and using a range of statistical performance metrics for evaluation. PFCONUSv1 comparisons with these datasets are a promising indicator of model fidelity and ability to reproduce the continental-scale water balance at high resolution. Areas for improvement are identified, such as a positive streamflow bias at gauges in the eastern Great Plains, a shallow water table bias over many areas of the model domain, and low bias in seasonal total water storage amplitude, especially for the Ohio, Missouri, and Arkansas River basins. We discuss several potential sources for model bias and suggest that minimizing error in topographic processing and meteorological forcing would considerably improve model performance. Results here provide a benchmark and guidance for further PFCONUS model development, and they highlight the importance of concurrently evaluating all hydrologic components and fluxes to provide a multivariate, holistic validation of the complete modeled water balance.

The paper presents the case study of the recurrent slope movement in colluvium deposits at Doi Chang, Thailand. A thorough site investigation confirmed the slope movement rate corresponding to slow creep during dry season, while in the rainy season, its velocity remarkably increased. Despite frequent repair, the movement rate was sufficient to result in the recurrent damage of infrastructures like roads and buildings, causing economic loss and public concerns. Furthermore, surface mapping revealed that the hill's topography led to the concentration of flowing water in a particular area. This resulted in a high level of groundwater table, especially during the rainy season. The inclinometer installed in that area suggested an average movement rate of 20.5 mm/month in the wet season. In contrast, during the dry season, it was limited within 2 mm/month, indicating that the increase in the rate of slope movement in the colluvium deposit was primarily due to the rising groundwater table. Field and laboratory tests were conducted to determine the properties of the colluvium deposit. Landslide susceptibility assessment was performed using infinite slope model and later integrated with GIS to evaluate the factor of safety (FS) over a large area. The FS decreased below 1 when the groundwater level rose to 0.3 cm below the ground surface, and using GIS, based on infinite slope model, the potential risk zone were delineated.

The area around the town of Mangalia in Southern Dobrogea (Romania) hosts a unique karst landscape represented mostly by large collapse dolines. Around one of these collapse dolines, named Obanul Mare, there is a peculiar morphology of hillocks that resemble the tropical labyrinth-cone karst but on a much-reduced scale. This peculiar relief was hypothesized to be residual, resulting from the ceiling collapse of a two-dimensional maze cave. This type of maze caves form when the water table remains stable for long periods of time, allowing groundwater to dissolve the carbonate host rock along all available discontinuities. The Obanul Mare structure contains a 200 m long cave (Movile cave), whereas a few kilometers away we can find Limanu maze cave, whose passages sum up to more than 3,500 m. Because the existence of a former maze cave is difficult to demonstrate, in this study we took an indirect approach to this issue. We hypothesize that if there was a maze cave and its ceiling collapsed, then the inner walls would be left standing as pillars. Subsequent subaerial evolution of these pillars would create slopes that would incline towards the former cave passages. By quantifying the slope aspect from a high-resolution digital surface model, we would be able to identify the direction of the original passages, hence the main hypothetical fracture lines along which those passages formed. By comparing these orientations to those of local fractures (deduced from the nearby valley and doline axes), as well as with the orientations of the Movile Cave passages, we found that they are well correlated. This strengthens the hypothesis that the hillocky terrain is tectonically conditioned and that it might be the result of cave ceiling collapse, bringing more information on the existence of maze caves in the region. La zone autour de la ville de Mangalia dans le sud de la Dobrogea (Roumanie) abrite un paysage karstique unique représenté principalement par de grandes dolines effondrées. Autour de l'une de ces dolines d'effondrement, appelée Obanul Mare, il existe une morphologie particulière de buttes qui ressemble aux karsts à cône labyrinthiques tropicaux, mais à une échelle très réduite. Au sein de ce travail, nous proposons l'hypothèse que ce relief particulier était résiduel, résultant de l'effondrement du plafond d'une grotte labyrinthe bidimensionnelle. Ce type de grottes labyrinthiques se forme lorsque la nappe phréatique reste stable pendant de longues périodes, permettant aux eaux souterraines de dissoudre la roche carbonatée hôte le long de toutes les discontinuités disponibles. La structure Obanul Mare contient une grotte de 200 m de long (grotte Movile), tandis qu'à quelques kilomètres de là se trouve la grotte Limanu, dont les passages totalisent plus de 3 500 m. Parce qu'il est difficile de démontrer l'existence d’une ancienne grotte-labyrinthe, dans cette étude, nous avons adopté une approche indirecte de la question. Nous émettons l'hypothèse que s'il y avait une grotte-labyrinthe et que son plafond s'effondrait, alors les murs intérieurs resteraient debout tels des piliers. Les phases d’érosion subaérienne postérieures de ces piliers créeraient des pentes qui s'inclineraient vers les anciens passages de la grotte. En quantifiant l'aspect de la pente à partir d'un modèle de surface numérique à haute résolution, nous pourrions identifier la direction des passages d'origine, d'où les principales lignes de fracture hypothétiques le long desquelles ces passages se sont formés. En comparant ces orientations à celles des fractures locales (déduites des axes de vallées voisines et dolines), ainsi qu'avec les orientations des passages de Movile Cave, nous avons trouvé qu'elles sont bien corrélées. Cela renforce l'hypothèse selon laquelle le terrain vallonné est conditionné tectoniquement et qu'il pourrait être le résultat de l'effondrement du plafond de la grotte, apportant plus d'informations sur l'existence de grottes labyrinthiques dans la région.

In dry-hot areas, such as southern Tunisia, the availability of good water is very limited by the low scanty rainfall, the long dry periods and the high evaporation rate. Thus, to deal with these issues, information concerning the quality of irrigation water and the variability of groundwater quality across the oasis system from water well to the final runoff released into the natural environment, is required to evaluate the potential impacts on agricultural soil fertility and to assess the effects of land-use and agricultural practices in environmental conservation and natural resources exploitation. In the current study, 28 water samples have been collected from public wells along the irrigation scheme and drainage canals and have been analyzed. The obtained data prove that groundwater has large spatial variability (EC between 2.93 and 10.05 ms/cm and TDS between 1.95 and 8.15 g/L) caused by different influencing factors such as aquifer water quality, overexploitation, distribution system and evaporation processes. According to the used ionic ratios (SAR, KR, PI, MH, TH, SSP, ESP, etc..), the used waters are locally of permissible quality, while the majority fall unsuitable class to be used in irrigation with a maximum SAR of 18 at El Hamma region. The findings indicate that, besides the severe restrictions required for the use of these high mineralized resources, CI water quality shows a slight variability along irrigation scheme, which may provide additive water resources that may be reused in agriculture, the runoff released into the environment and the excess of irrigation water lost to evaporation process. The evaluation of chemical quality of drainage water may provide a scientific basis for the reuse of these waters to more efficient land management aiming to the sustainable development of oasis agriculture and the prevention of land degradation.

Stream restoration, such as channel reconfiguration and riparian zone revegetation, is increasing in response to aquatic impairment in agroecosystems. Though riparian zones effectively remove nitrogen (N), conditions that foster nitrate (NO3−) removal (e.g., soil saturation, low oxygen, available carbon) may facilitate the release of soluble reactive phosphorus (SRP) and greenhouse gases (GHGs—carbon dioxide [CO2], methane [CH4], and nitrous oxide [N2O]). In this study, water quality and GHG fluxes were quantified seasonally at agricultural restored, unrestored, and forested riparian zones via networks of wells and static chambers. Carbon dioxide comprised the majority of GHG emissions, and CO2 fluxes were lower at the restored site than the forested site (medians: 0.71 g C m−2 day−1 and 1.29 g C m−2 day−1, respectively). The restored site was a net CH4 source (median: 1.20 mg C m−2 day−1), while the other sites were net CH4 sinks (medians: − 1.00 to − 1.76 mg C m−2 day−1). Sites had comparable N2O emissions. Subsurface SRP was lower at the restored than unrestored agricultural sites, while median NO3− removal efficiency was higher (restored: 91%, unrestored: 35–66%). Over time, NO3− removal and CO2 fluxes increased post-restoration. Methane emissions were elevated when the restored riparian zone was a CO2 and N2O sink and NO3− removal was high. Despite variability within and between sites, seasonal conditions (temperature, water table height, precipitation) and site characteristics (geomorphology, soils) remained key explanatory variables for riparian N removal and GHG release. Overall, riparian restoration may promote N removal without increasing total GHG emissions.

Sub-surface oil-polluted soils are frequently subjected to temporal groundwater table fluctuations during which the biological and chemical properties of the soil are expected to change in response to hydrological variations. In this study, we investigated the influence of decreasing groundwater levels on soil enzymatic activities, microbial community and total hydrocarbon dynamics. The changes in enzymatic activities, hydrocarbon removal efficiencies and bacterial community structure in the petroleum polluted soil were monitored by routine collection and testing of soil samples every 20 days over a period of 80 days in a laboratory column setup. Polymerase chain reaction and high-throughput sequencing of soil microbial DNA were used to determine the compositions of microorganisms, alpha and beta diversity in the polluted soil while the soil enzymatic activities and total petroleum hydrocarbon were measured using spectrophotometry and gas chromatography–mass spectrometry, respectively. The results showed that experimental decreases in groundwater levels over 80 days led to increased soil alkalinity, modulated enzymatic activities and enhanced total petroleum hydrocarbon attenuation in sub-surface soil. The findings from this study will be very useful in designing and optimizing bioremediation strategies for petroleum polluted soils from cold temperate regions.

We introduce here SOIL-WATERGRIDS, a new dataset of dynamic changes in soil moisture and depth of water table over 45 years from 1970 to 2014 globally resolved at 0.25 × 0.25 degree resolution (about 30 × 30 km at the equator) along a 56 m deep soil profile. SOIL-WATERGRIDS estimates were obtained using the BRTSim model instructed with globally gridded soil physical and hydraulic properties, land cover and use characteristics, and hydrometeorological variables to account for precipitation, ecosystem-specific evapotranspiration, snowmelt, surface runoff, and irrigation. We validate our estimates against independent observations and re-analyses of the soil moisture, water table depth, wetland occurrence, and runoff. SOIL-WATERGRIDS brings into a single product the monthly mean water saturation at three depths in the root zone and the depth of the highest and lowest water tables throughout the reference period, their long-term monthly averages, and data quality. SOIL-WATERGRIDS can therefore be used to analyse trends in water availability for agricultural abstraction, assess the water balance under historical weather patterns, and identify water stress in sensitive managed and unmanaged ecosystems., Measurement(s)volumetric water content • water table depthTechnology Type(s)computational modeling techniqueFactor Type(s)hydrometeorology • soil properties • land useSample Characteristic - Environmentsoil Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.15982578

Tunnels excavated under the water table may need a face support pressure to ensure its stability. When such support pressure is too high to be provided by traditional support measures, advance drainage is required. But drainage lowers the water table, hence increasing the surface settlements and their effects on nearby structures. This work studies the surface settlements induced by tunnel face advance drainage boreholes, and their relationship with the tunnel face stability, using a numerical model of a shallow tunnel with different values of the applied support pressure. Results show that advance drainage produces a “more stable” situation, as less face support pressure is required for stability, while increasing surface settlements and, consequently, the risk to nearby structures. The critical pressures computed with a rotational Limit Analysis failure mechanism are also analyzed, preliminarily suggesting that they correspond to the asymptotic values of the stand-up time.

Alternate wetting and drying (AWD) is an irrigation technique where water is applied to the field a number of days after disappearance of ponded water. This is in contrast to the traditional irrigation practice of continuous flooding (i.e., never letting the ponded water disappear). This means that the rice fields are not kept continuously submerged but are allowed to dry intermittently during the rice growing stage. The number of days where the field is allowed to be “non-flooded” before irrigation is applied can vary from 1 to more than 10. The underlying premise behind this irrigation technique is that the roots of the rice plant are still adequately supplied with water for some period (due to the initial flooding) even if there is currently no observable ponded water in the field. There is a specific form of AWD called “Safe AWD” that has been developed to potentially reduce water inputs by about 30%, while maintaining yields at the level of flooded rice. In Safe AWD, the ponded water on the field (also called “perched water”) is allowed to drop to 10–15 cm below the soil surface before irrigation is applied. The depth of perched water is monitored using a perforated or punctured water tube embedded in the soil. With the threshold of 10–15 cm, roots are still able to extract water from the perched water table and no stress to the plants develops.

In the last three decades, a series of large landslides have occurred in the Siguas River Valley, Peru, and their causes have been attributed to irrigation input affecting the local groundwater conditions. While the causal relationship of the irrigation water to these landslides is widely accepted, the actual groundwater conditions necessary to initiate these landslides have not been previously quantified. In this paper, we present finite element modeling work to estimate the critical groundwater conditions required to initiate failure for the Zarzal and Pachaqui Chico Landslides, given back-calculated strength parameters, topography, and remote estimates of the likely range of possible groundwater scenarios. Modeling results indicate that elevated groundwater tables are required for landslide initiation and that these elevated groundwater tables are more likely due to perched zones forming from irrigation water input, rather than from elevation of the original deeper water table. In addition, the moisture content outside the saturated zone appears to be a less significant factor in landslide initiation than the position and configuration of the saturated zones. These results compare favorably to groundwater data acquired since the initiation of these landslides. Understanding of the groundwater conditions at initiation is important for designing mitigation to help prevent future landslides, and several mitigation options are briefly discussed.

An assessment of liquefaction potential for the Kathmandu Valley considering seasonal variability of the groundwater table has been conducted. To gain deeper understanding seven historical liquefaction records located adjacent to borehole datapoints (published in SAFER/GEO-591) were used to compare two methods for the estimation of liquefaction potential. Standard Penetration Test (SPT) blowcount data from 75 boreholes inform the new liquefaction potential maps. Various scenarios were modelled, i.e., seasonal variation of the groundwater table and peak ground acceleration. Ordinary kriging, implemented in ArcGIS, was used to prepare maps at urban scale. Liquefaction potential calculations using the methodology from (Sonmez, Environ Geol 44:862–871, 2003) provided a good match to the historical liquefaction records in the region. Seasonal variation of the groundwater table is shown to have a significant effect on the spatial distribution of calculated liquefaction potential across the valley. The less than anticipated liquefaction manifestations due to the Gorkha earthquake are possibly due to the seasonal water table level.

Due to financial wherewithal, only shallow wells, which are extremely prone to seasonal groundwater decline, are constructed in the study area. Generally, new groundwater wells are designed to follow the criteria of the old wells, which may be vulnerable to substantial groundwater depletion through water-level decline. Going by this, newer groundwater wells constructed near older ones are 100% susceptible to the uninvestigated depletion associated with the older ones. The method used integrates vertical electrical sounding (VES) technique employing the Schlumberger electrode configuration, which measured the resistivity of geologic layers, depths and thickness with hydrogeological information, which constrained the VES interpretation. The aim was to check the spread of groundwater depth–water table ratios for the shallow aquifers. The 1-D resistivity analysis shows that the topsoil/motley topsoil has resistivity ranging from 71.8 to 1964.1 $$\Omega m$$ and mean 586.9 $$\Omega m$$ , while its depth ranges between 0.5 and 11.3 m with mean value of 2.8 m. In layer 2, while the resistivity spans between 71.3 and 1488.6 $$\Omega m$$ with mean value 444.6 $$\Omega m$$ , the depth and thickness, respectively, have a range and mean value of 2.0–170.4 m and 41.9 m and 3.4–112.2 m and 41.0 m. The third layer resistivity ranges from 7.5 to 2332.5 $$\Omega m$$ with mean value of 797.2 m. The depth of burial and the thickness of the third layer, respectively, have mean of 63.0 m and 74.6 m and range of 40.3–106.3 m and 50.1–115.6 m. The fourth layer penetrated by current at 150 m half of current electrode separation has undefined thickness and depth with respective resistivity range and mean of 25.3–2385.3 $$\Omega m$$ and 508.4 $$\Omega m$$ . Based on the resistivity results and nearby borehole data, sizeable numbers of borehole in the area have depths (between 40 and 80 m) that are remarkably greater than the water table depths (1.4–37.6 m). A few boreholes have depths that are sparingly greater than water levels and by the present climate change; they are not likely to be depleted by virtue of water-level declines as the well depth–water table depth ratios are still sustainable to ward off the depletion associated with water-level decline. The results indicate the spatial spread of shallow hydrogeological units as well as the water-level architecture, which is believed to provide useful information that will complement lithological logs while planning for newer groundwater well development in the area.

Purpose Gaya, the holy city of Hindus, Buddhists and Jains, is facing an acute shortage of potable water. Although the city is blessed with some static and dynamic water bodies all around the region, they do not fulfill the requirement of millions of public either inhabitants of the area or tourists or pilgrims flocking every day. Countless crowds, congested roads, swarming pedestrians, innumerable vehicles moving throughout the day and night have made the city into a non-livable one. The present status of surface water is a mere nightmare to the requirements of the people. Due to which, massive ground water pumping mostly illegally has added a grid in addition to the other socio-economic issues. Design/methodology/approach To focus on such problem, the ground water of the region was studied thoroughly by calculating the depth of water level, discharge, pre-and post-monsoon water table and specifically the storativity in ten different locations. Some data were acquired, others were assessed, and few are calculated to provide an overall view of the ground water scenario. Findings After a long and tedious field study, it was finally established from that static water level ranges from 2.45 to 26.59 m, below ground level (bgl), discharge varies from 3.21 m3/day to 109.32 m3/day. Post pumping drawdown falls between 0.93 m and 16.59 m, whereas the specific capacity lies in between 0.96 and 7.78 m3/hr/m. Transmissivity, which is a key objective to assess ground water potential ranges from 109.8 to 168.86 m2/day. Originality/value This research work is original.

Source parameters were estimated using multiple empirical Green’s functions (meGf) method for 2 clusters of shallow depth and small-magnitude earthquakes induced by the infiltration due to gravity into the groundwater zone after heavy monsoons during October 1998 and October 2017, in Hyderabad, South India. First, four decades of earthquake catalogue data recorded by HYB seismic station at CSIR-National Geophysical Research Institute (NGRI) was used to characterize the spatiotemporal variation in seismicity. Enhanced seismicity was noticed because of the strong seasonal fluctuations of the groundwater table during the post-monsoon season. Second, focus was on the estimation of source parameters for two cluster of swarm events whose local magnitude (Ml) are in −0.09

Groundwater samples from Kapurthala (45), Jalandhar (70), and Hoshiarpur (70) districts from northern Punjab, India, were studied for seasonal variation (pre-monsoon and post-monsoon) of uranium distribution and physicochemical parameters, quality and suitability for drinking purposes, source apportionment, and health risks. The average uranium concentration (in μg L−1) in Kapurthala, Jalandhar, and Hoshiarpur districts was 12.7, 18.8, and 7.0, respectively, in pre-monsoon and 8.0, 17.3, and 5.6, respectively, in post-monsoon. In both seasons, uranium concentration was below WHO limit (30 μg L−1) in more than 90% of groundwater samples, and it was found to exhibit positive correlation majorly with TDS, EC, and total alkalinity. Principal component analysis revealed dissolution of rocks/minerals contributing to mineralization of associated aquifers in addition to some anthropogenic activities such as excessive application of fertilizers/pesticides and dumping of domestic waste followed by their seepage into the groundwater table. All groundwater samples fall in very good to good drinking groundwater quality and its quality is more improved in post-monsoon season owing to dilution of various inorganic salts during groundwater recharge in monsoon season. Average Hazard Index (HI) values due to ingestion of U, F−, and NO3− via drinking water for both adults and children were found to be marginally greater than safe limit of 1 with major contribution from F−. It is advisable to local government/public that regular monitoring of groundwater and proper management policies or strategies should be adopted followed by their implementation to control groundwater pollution in three districts.

To improve the accuracy of hydrological simulations in the groundwater overexploitation zone of North China, it is necessary to study the characteristics of shallow aquifer recharge on daily scale. Three shallow aquifer recharge indices were used to quantify shallow aquifer recharge in two ways. The recharge coefficient was used to quantify the amount of shallow aquifer recharge. The recharge duration and water table rise coefficient were used to quantify the recharge temporal process. The Spearman rank correlation coefficient and regression analysis were used to determine the relationships between aquifer water table depth (WTD), rainfall, and shallow aquifer recharge. The Jiangjiang River Basin, a tributary of the Haihe River, was selected as the study area. The results showed that the recharge coefficient first increased, then decreased, and finally leveled off as WTD increased. When WTD was between 5 and 6 m, the recharge coefficient reached its maximum (approximately 0.3). When WTD was greater than 10 m, the recharge coefficient remained stable (around 0.12). With regard to the sources and forms of recharge, preferential flow was dominant in the areas near the extraction wells. In contrast, plug flow became dominant in the areas distant from the wells. With the reduction of rainfall duration, the proportion of preferential flow contributing to aquifer recharge increased. With the increase of rainfall amount, the duration of aquifer recharge lengthened.

An investigation was undertaken to predict the post-closure water chemistry of the Cortez Hills Underground Deep South Extension where the mine workings will be backfilled with cemented waste rock. The objective was to determine the potential effects of the tunnel water on adjacent groundwater once the groundwater table recovers, hydraulic conditions stabilize, and ambient groundwater flow is reestablished. The average background groundwater chemistry from three wells representing discharge to the tunnel area during closure, and the worst-case groundwater dissolution chemistry of tunnel floor/unconsolidated backfill, shotcrete (sprayed concrete), cemented backfill and country wallrock/cemented backfill reactions were used to calculate their contribution to the total mass loading during tunnel flooding. The volume of groundwater flow through the tunnel area was coupled with these releases to calculate a total tunnel water quality. All analytes met NV Division of Environmental Protection Profile I standards, except for As, Sb, and Pb, due to their naturally-elevated background groundwater levels (0.08, 0.014, and 0.03 mg/L, respectively). The PHREEQC geochemical code was used to determine the post-closure dissolved phase solutes that could migrate to adjacent groundwater. The dissolved tunnel water chemistry was predicted to be pH = 8.2, with an alkalinity of 124 mg/L CaCO3 and with all solutes meeting Profile I except for As (0.07 mg/L) and Sb (0.01 mg/L). The predicted water chemistry was dominated by the influent groundwater, which comprised ≈97% of the mass loading and was similar to two existing underground seeps.

An improved understanding of the relationships among vegetation, groundwater level, and microtopography is crucial for making well-informed management decisions in areas with shallow groundwater resources. We measured plant species abundance/composition and richness in relation to depth to groundwater (DTW) and microtopography in Owens Valley, California, particularly in areas where DTW ranged from 0 to 4 m. Sampling occurred along 67 vegetation transects across three community types. Relationships between DTW and community composition were evaluated using non-metric multidimensional scaling (NMS), while non-parametric multiplicative regression was used to relate DTW and microtopography to species abundance. The dominant gradient in species composition (NMS Axis 1) explained ~51% of variation in our distance matrix and was most strongly associated (r = 0.55) with DTW. The graminoids Juncus arcticus, Leymus triticoides, and Distichlis spicata had strong affinities toward areas with the shallowest DTW ( 2.0 m). Variation in microtopography affected species abundance and increased species richness for vegetation communities at either extreme of the water table gradient, shallow, and deep DTW but not the intermediate DTW. Findings indicate that desert plant communities from shallow aquifers have adapted to different DTW and microtopography conditions and that considering those adaptations may be important to manage groundwater and vegetation resources in these areas.

A study of the engineering properties of the subsurface soil in the Greater Jos Master Plan development area has been carried out to address the paucity of engineering data in the area. The study became necessary because the rapid urbanization has led to limited construction land with more ground prone to instability due to reworking by mining and related activities. The study area is located within Latitudes 09º 48' 20'' to 09º 53'20''N and Longitudes 08º 53' 54'' to 08º 57 '00'' E and extending over 54km2 on Naraguta Sheet 168NE. Surface geological mapping was carried out to confirm the existing geology. Geotechnical properties of soils were determined by analysis of soil samples for 38 locations. While 94 static water level measurements provided additional information on groundwater conditions. The area is underlain by the Jos-Bukuru Complex rocks predominantly biotite granites differentiated on the basis of mode of formation, mineralogy and texture. Soils derived from weathering of the rocks revealed gradual decomposition from gravel, sand, and silt-sized particles to lateritic clays. The soils are considered to have low to medium plasticity/compressibility, expansiveness, and swelling potential across all rock types. The static water table depicts fluctuation in the water table varying between 2.9 and 3.9m. These findings are expected to serve as guide in the choice of design and construction and as a baseline subsurface soil compendium for planning and urban development in the Greater Jos Master plan and for further studies.

Artificial groundwater recharge is an important component of water resources management in arid areas. Knowledge of the surface-water/groundwater interaction in a stream–aquifer system is important for sustainably managing the aquifer and obtaining the expected environmental benefits. In this study, an analytical solution of the linearized one-dimensional Boussinesq equation was obtained by using the Laplace transform; then, improved analytical models of multistage recharge were constructed on the basis of the spreading effect and delay effect to model the multiyear water-table fluctuations in a homogeneous, isotropic, unconfined aquifer under intermittent artificial recharge conditions. In addition, sensitivity analyses were performed to assess the responses of the water-table fluctuations to changes in each controlling hydrogeological parameter. To further validate the proposed method, the analytical models were applied to estimate the multiyear water-table fluctuations in the intermittent artificial groundwater recharge basin of the downstream of Tarim River, northwestern China. The results indicated that the analytical solutions and improved analytical models, which utilize the variation in the water table as a boundary condition, can explain the rise and fall of the water table within the unconfined aquifer. The accuracy of the simulation results was tested through a comparison with observations, and the results demonstrated that the models can effectively reflect the water-table fluctuations under transient recharge, spreading recharge and multistage recharge conditions. These findings can provide a theoretical basis and references for studying and modeling the water-table fluctuations under intermittent artificial recharge conditions spanning multiple years.

Wetland CH4 emissions have been demonstrated to be more sensitive than wetland CO2 emissions to increasing temperatures, which may result in a greater relative contribution of CH4 to total GHG emissions under climate warming. However, it is not clear whether this greater sensitivity occurs globally across diverse hydrologic regimes. Here, we evaluate the temperature dependence of CO2 and CH4 emissions on water table depth using a global database and show similarities in the temperature dependence of CO2 and CH4 emissions. A lower water table is associated with a decrease in the temperature dependence of CH4 emissions and a higher water table has the opposite effect. Water table depth does not affect the temperature dependence of CO2 emissions. Our findings suggest the stimulatory effect of increasing temperature on wetland CH4 emissions may not always be stronger than that on CO2 emissions and depends on the wetland water table. Climate change may result in larger releases of CH4 than CO2 from wetlands as CH4 emissions seem to be more sensitive to temperature. Globally, CO2 and CH4 emissions show a similar temperature dependence but this is modulated by wetland water table depth, which affects CH4 (but not CO2) emissions.

Freezing-induced groundwater-level decline is widely observed in regions with a shallow water table, but many existing studies on freezing-induced groundwater migration do not account for freezing-induced water-level fluctuations. Here, by combining detailed field observations of liquid soil water content and groundwater-level fluctuations at a site in the Ordos Plateau, China, and numerical modeling, we showed that the interaction of soil water and groundwater dynamics was controlled by wintertime atmospheric conditions and topographically driven lateral groundwater inflow. With an initial water table depth of 120 cm and a lateral groundwater inflow rate of 1.03 mm d−1, the observed freezing and thawing-induced fluctuations of soil water content and groundwater level are well reproduced. By calculating the budget of groundwater, the mean upward flux of freezing-induced groundwater loss is 1.46 mm d−1 for 93 d, while the mean flux of thawing-induced groundwater recharge is as high as 3.94 mm d−1 for 32 d. These results could be useful for local water resources management when encountering seasonally frozen soils and for future studies on two- or three-dimensional transient groundwater flow in semi-arid and seasonally frozen regions. By comparing models under a series of conditions, we found the magnitude of freezing-induced groundwater loss decreases with initial water table depth and increases with the rate of groundwater inflow. We also found a fixed-head lower boundary condition would overestimate freezing-induced groundwater migration when the water table depth is shallow. Therefore, an accurate characterization of freezing-induced water table decline is critical to quantifying the contribution of groundwater to hydrological and ecological processes in cold regions.

Purpose This paper aims to study the effect of mineral additions on the mortars’ physical, mechanical and durability properties. Two local mineral additions, considered inert, are chosen: limestone fillers from North-East of Algeria and natural dune sand from Algerian desert areas. Design/methodology/approach Two local additions are finely crushed to a fineness greater or equal to that of the used cement and incorporated into the mortars with predetermined rates; (0, 10%, 15% and 20%) compared to the cement weight to examine their effects on the mortars’ properties at different ages. Two conservation environments are chosen: freshwater as a neutral area and rising water table as an aggressive area to appreciate the effect of the two additions on physical and mechanical properties and durability. Findings The results showed the beneficial effect of these additions on compactness, mechanical resistance and durability toward the rising water table. The results have also allowed us to make an experimental comparison between the limestone addition which is commonly used in the Algerian cement industry and the dune sand, which is not yet well explored and exploited. Originality/value The added value of this study is the use of crushed dune sand which is a local addition of southern Algeria for improving the resistance of mortars and concrete toward the aggressiveness of rising water table which presents a major problem for the infrastructure of civil and public construction.

Previous research involving turfgrass response to soil moisture used methodology that may compromise root morphology or fail to control outside environmental factors. Water-table depth gradient tanks were employed in the greenhouse to identify habitat specialization of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] and manilagrass [Zoysia matrella (L.) Merr.] maintained at 2.5 and 5.1 cm. Turfgrass quality (TQ), normalized difference vegetation index (NDVI), canopy temperature (CT), and root biomass (RB) were used as metrics for plants grown in monoculture in sandy clay loam soil. Mowing height did not affect growth of turfgrass species in response to soil moisture. Turfgrass quality, NDVI, and RB were greatest, whereas CT was lowest at wetter levels [27- to 58-cm depth to the water-table (DWT)] of each tank where plants were growing at or above field capacity. However, bermudagrass RB was greatest at 27-cm DWT, whereas manilagrass RB at 27-cm DWT was lower than RB at 42.5- to 73.5-cm DWT in 2013 and lower than all other levels in 2014. Both species responded similarly to droughty levels (120- to 151-cm DWT) of the tanks. Turfgrass quality, NDVI, and RB were lowest, whereas CT was highest at higher droughty levels. Bermudagrass may be more competitive than manilagrass when soil moisture is high whereas both species are less competitive when soil moisture is low.

The current study evaluated the hydrogeological conditions and hydraulic properties of the groundwater aquifers in Qaraqosh, Karamless and Bartella areas within Al-Hamdaniya district east Mosul. The depths and water tables of groundwater for 48 well were measured in October 2019, were ranged between 5 - 45 meters and 234 - 278.5 meters, respectively. The highest water table reaches in the center of the studied area north Qaraqosh and decreases gradually in all directions. A map of the flow net was drawn, and it was found that the general direction of water movement is from north to south, with local directions resulting by pumping from the aquifer, or due to the heterogeneity of the porous media. The results of the pumping test in Karamless area shows that the transmissivity was 107.671 m2/day and 100.682 m2/day according to Theis and Cooper-Jacob methods, respectively. The hydraulic conductivity of 157.65 m saturated thickness was found to be 0.683 m/day and 0.639 m/day using Theis and Cooper-Jacob methods, respectively. While the storage coefficient using Theis and Cooper-Jacob methods was 0.0023 and 0.0020، respectively. In Qaraqosh, the transmissivity was 87.1685 m2/day and 88.1004 m2/day according to the mentioned methods, respectively. While the hydraulic conductivity of saturated thickness of 71.07 m was found to be 1.24 m/day and 1.23 m/day using Theis and Cooper-Jacob methods, respectively. The values of storage coefficient using these methods was 0.00135 and 0.00115 respectively. The total dissolved solids (TDS) measured to conclude the hydrogeological system according to the quality of the groundwater aquifers, it was found that the concentrations of total dissolved solids are more than 3500 ppm in the mid of the study area and decreased towards all directions to the limits of 250 ppm. This wide variation in salinity may be because the wells in the central area penetrate the groundwater aquifers, represented by the layers of gypsum in Al-Fat'ha formation, which is hydraulically connected with the main aquifer of the Injana formation.