Groundwater Level Conditions Research Articles

Research on a Non-Stationary Groundwater Level Prediction Model Based on VMD-iTransformer and Its Application in Sustainable Water Resource Management of Ecological Reserves

The precise forecasting of groundwater levels significantly influences plant growth and the sustainable management of ecosystems. Nonetheless, the non-stationary characteristics of groundwater level data often hinder the current deep learning algorithms from precisely capturing variations in groundwater levels. We used Variational Mode Decomposition (VMD) and an enhanced Transformer model to address this issue. Our objective was to develop a deep learning model called VMD-iTransformer, which aims to forecast variations in the groundwater level. This research used nine groundwater level monitoring stations located in Hangjinqi Ecological Reserve in Kubuqi Desert, China, as case studies to forecast the groundwater level over four months. To enhance the predictive performance of VMD-iTransformer, we introduced a novel approach to model the fluctuations in groundwater levels in the Kubuqi Desert region. This technique aims to achieve precise predictions of the non-stationary groundwater level conditions. Compared with the classic Transformer model, our deep learning model more effectively captured the non-stationarity of groundwater level variations and enhanced the prediction accuracy by 70% in the test set. The novelty of this deep learning model lies in its initial decomposition of multimodal signals using an adaptive approach, followed by the reconfiguration of the conventional Transformer model’s structure (via self-attention and inversion of a feed-forward neural network (FNN)) to effectively address the challenge of multivariate time prediction. Through the evaluation of the prediction results, we determined that the method had a mean absolute error (MAE) of 0.0251, a root mean square error (RMSE) of 0.0262, a mean absolute percentage error (MAPE) of 1.2811%, and a coefficient of determination (R2) of 0.9287. This study validated VMD and the iTransformer deep learning model, offering a novel modeling approach for precisely predicting fluctuations in groundwater levels in a non-stationary context, thereby aiding sustainable water resource management in ecological reserves. The VMD-iTransformer model enhances projections of the water level, facilitating the reasonable distribution of water resources and the long-term preservation of ecosystems, providing technical assistance for ecosystems’ vitality and sustainable regional development.

Effects of microtopography on soil development of the conserved area in the Isahaya Bay polder

ABSTRACT After reclamation of the Isahaya Bay polder, a conserved area is covered with naturally developed vegetation under high groundwater level conditions. This study investigated how alluvial deposits transform into soil without utilizing artificial water drainage systems for agricultural land uses. Soils were surveyed under four vegetation compositions, including those dominated by goldenrods (GR), occupied by high-grown reeds (HRD), covered with low-grown reeds (LRD), or a mixture of goldenrods and reeds (MIX). The microtopography of the polder differentiated the research site with a higher elevation at the GR location, followed by a MIX, HRD, and a lower elevation at the LRD location. The soils were characterized by their physicochemical properties and ionic composition of the soil water. Electrical conductivity (EC), which can be an indicator of residual seawater, was lowest in the GR, followed by the MIX, HRD, and LRD. The soil moisture regimes affected by microtopography led to different frequencies of wet-dry cycles in the soil, resulting in a developing sequence of soil structure from LRD to GR with decreasing EC. The ionic composition of soil water varied with elevation and soil depth. The residual seawater still influenced the ionic composition of deeper soil horizons at lower elevations, while specifically high rates of Ca2+ and SO4 2− were observed in GR. The oxidation of pyrite is stimulated by soil aeration with lowering water level, resulting in soil acidification and the simultaneous dissolution of calcium carbonate from seashells. The sequential changes in soil properties with elevation indicated the effects of microtopography on soil moisture dynamics, which led to variations in soil formation and vegetation in the conserved area.

Evaluation of Slope Stability at Interface using Thin Soil Material Model in Finite Element Software

Cases of landslides on clay shale slopes have been an intriguing study in Indonesia. Most of the slopes failed due to the weathering of the clay shale rock. As studies focused on the properties of clay shale, several FEM analyses indicated a unique translational type of failure between the interface of clay shale and its overburden. However, the modeling of the interface in a case study was still limited. This study aims to evaluate a landslide using a thin-soil interface model using FEM software. The model used two conditions, extreme groundwater level conditions. There were several iterations of the shear strength parameters of the interface layer conducted. Results indicated that the thin-soil interface could portray the interface condition at the landslide. Compared to laboratory interface results, the interface would fail at a high degree of saturation due to water infiltration at the surface. Also, granular overburden with high permeability had a higher chance of failure than cohesive overburden. From the results, this study opened the path to incorporating the interface layer in clay shale slope analysis. However, further studies are needed using the thin-soil interface model in other clay shale landslide cases to synthesize its repeatability.

Slope stability analysis during an earthquake in flow-slide affected area of Jono Oge

On September 28th, 2018, the earthquake with a moment magnitude (Mw) 7.5 due to strike-slip Palu-Koro Fault in Central Sulawesi caused a major geological failure. In the Jono Oge area, the earthquake-induced liquefaction and flow-slide occurred on relatively flat ground with an average slope of 2%. In this paper, the safety factor for slope stability analysis was determined by shear strength reduction caused by the earthquake at the potentially liquefied soil layer, varying peak ground acceleration values, and groundwater level conditions. This analysis evaluated the potential of ground movement occurrence in Jono Oge with the condition of soil layer pre and post the Palu-Donggala earthquake that happened in 2018 using GeoStudio Slope/W geotechnical software. The analysis was conducted on the cross-section of the soil layer based on three boreholes incorporating standard penetration test (SPT) data on the study area. The analysis results showed ground movement potential because of the seismic loads and groundwater level conditions. The lower the safety factor of slope stability, the higher the ground movement potential in flow-slide affected area. This ground movement potential could trigger the occurrence of flow-slide in Jono Oge area.

An analysis of the influences of groundwater level changes on the frost heave and mechanical properties of trapezoidal channels

Abstract In this research study, platforms with different heights were established for the purpose of simulating the different groundwater level conditions. Combined with the prototype channel, the influences of the groundwater level changes on the frost heave deformations in the foundation soil and on the frost heave force of the channel, as well as on the bending moment of the channel section and water content migration of the foundation soil, were studied by the method of mechanical analysis. The research results show that, after a comparative analysis of the ground temperatures in the same layer had been completed, the difference value was found to have been less than 5%. The frost heave of the foundation soil had decreased by 0.15 cm for every 1 cm reduction in the groundwater level. In addition, the maximum frost heave force of the channel was shown to have varied with the change of groundwater level. This study's theoretical calculations determined that the most unsafe groundwater level of a typical channel was 2.61 m. It was concluded that the increase of groundwater level can reduce the amount of soil moisture transfer, while the influence of groundwater level on frost heave of foundation soil can be effectively reduced by laying polystyrene boards.

Analysis of rainfall-triggered landslide in Baleagung Village, Magelang Regency, Central Java

The majority of Magelang Regency is considered as intermediate and high susceptible areas against landslide. As happened in Baleagung Village in January 2018, a landslide has damaged local residency buildings. The landslide occurred because of high-intensity rainfall on the day before. Meanwhile, cracks formed in several areas that were indicated by the slope around the village were still actively moving. Therefore, mitigation is urgently needed to minimize the risk of further landslide movement. This study aimed to analyze the mechanism of ground movement at Baleagung Village which was affected by rainfall. This research was conducted by using back-analysis method to determine the initial groundwater level conditions and its effect on the slope stability. Soil parameters were obtained by laboratory testing and permeability tests in the field. Subsequently, rainfall data was collected from Himawari-8 satellite and used as the data input parameter for numerical analysis using SEEP/W and SLOPE/W. The results obtained from back-analysis showed that rainfall infiltration into the soil affected the degradation of safety factor value that was caused by the increase of pore-water pressure and the decrease of effective stress in a certain period. The degradation of safety factor was caused by the increasing of soil saturation degree when water infiltrated into the ground.

Landslide Mitigation of Banjir Kanal Semarang, with Grouting Method

Indonesia is aprone’s country to the occurrence of mass movements. These disasters often occur in various regions, especially during the winter. Banjir Kanal is one of the locations of landslides from the observation in the field, the type of ground motion that occurs in the research area such as slump, it caused by the intense weathering of rocks and triggered by a condition of ground water level, Vibration, and human activities. Soil material at the research area such as claystone as the original soil and sandy clay stone as fill soil. The soil conditions and slope angle that very steep about 60 degree is a factors causing mass movement. The purpose of this research to determine the type of ground motion, causes and triggers of mass movement at the research area, and to know the success level of grouting methods to overcome them. The research method that used is descriptive method and experimental methods. Slope stability analysis used by the Fellenius method that calculated to determine the value of safety factor (Fs) at the study site. Based on the results of such simulations could be seen that after the implementation of grouting, soil cohesion increased.

Responses of Water Fluxes and Water-Use Efficiency of Maize to Warming Based on Water Transformation Dynamical Processes Experimental Device (WTDPED) Experiment

Evaluating the impacts of warming on water balance components in the groundwater–soil–plant–atmosphere continuum (GSPAC) and crop growth are crucial for assessing the risk of water resources and food security under future global warming. A water transformation dynamical processes experimental device (WTDPED) was developed using a chamber coupled with a weighing lysimeter and groundwater supply system, which could simultaneously control both climatic and ground-water level conditions and accurately monitor water fluxes in the GSPAC. Two experiments with maize under increased temperature by 2 °C (T-warm) and ambient temperature (T-control) scenarios were conducted via the WTDPED. The duration of growing season decreased from 125 days under T-control to 117 days under 2 °C warming. There was little difference of total evapotranspiration (ET) (332.6 mm vs. 332.5 mm), soil water storage change (∆W) (−119.0 mm vs. −119.0 mm), drainage (D) (−13.6 mm vs. −13.5 mm) between T-control and T-warm experiments. The average daily ET for maize significantly increased by approximately 6.7% (p < 0.05) in the T-warm experiment, especially during the sixth leaf to tasseling—silking stage with an increase of 0.36 mm with respect to the T-control experiment. There were evident decreases in LAI (leaf area index), whereas non-significant decreases in mean stem diameter, crop height and leaf chlorophyll content under T-warm compared to T-control experiment. However, the chlorophyll content increased by 12% during the sixth leaf to tasseling–silking stage under 2 °C warming, which accelerated the photosynthesis and transpiration rate. The grain yield and water-use efficiency (WUE) for maize increased by 11.0% and 11.1% in the T-warm experiment, respectively, especially due to enhanced growth during the sixth leaf to tasseling–silking stage. This study provided important references for agricultural planting and water management to adapt to a warming environment.

Environmental risk resulting from historical land degradation in alluvial plains considered for dam planning

AbstractLand degradation of alluvial plains is an environmental risk for groundwater contamination, stemming from the mobilization of contaminants that can occur from waste‐filled gravel pits. This risk can be increased by river damming and consequential rises in groundwater levels. The presence and characteristics of former historical land degradation of alluvial plains should therefore be considered when planning hydroelectric projects. The aim of this study was to assess the hydrological and environmental impacts of the planned damming of the Sava River on the groundwater, which is the drinking water source for the Slovenian capital Ljubljana. It introduces an integrative approach for determining the characteristics of old waste‐filled gravel pits with stereo image processing of historical aerial photographs and electrical resistivity tomography (ERT) in combination with hydrological modelling. Thirty gravel pits in the study area (17 km2) were identified by stereo image analysis, and three were selected to test results in the field using non‐invasive ERT. Integrating this information with the results of hydrological modelling, we assessed the risk of groundwater contamination from the scenario of the planned damming of the River Sava. The results indicate that the thickness of the unsaturated zone below the identified gravel pits will be reduced by an average of 4 m at median groundwater level conditions during damming, which will increase the vulnerability of groundwater to contamination.

Groundwater Management Scenarios for the Biyadh-Wasia Aquifer Systems in the Eastern Part of Riyadh Region, Saudi Arabia

ABSTRACT Groundwater stored in the deep seated sedimentary aquifers is the most important source of water supply. The lack of sufficient groundwater recharge and the overdependence on groundwater might lead to unavailability of this precious natural resource if proper management practices are not adopted. Finite difference modelling using the MODFLOW program was carried out in the east of Riyadh city to simulate the groundwater level conditions under different abstraction scenarios. The simulated aquifer system combines the Wasia and Biyadh aquifer (composed of sandstone) and Aruma aquifer (limestone) which lies between 24°30’00”-25°30’00” N and longitudes 47°00’00”-48°00’00”E. The transmissivity and storage coefficient values of Biyadh aquifer are 7.0x10−3 to 7.0x10−2 m2/day and 3.7x10−4 to 9.4x10−4 respectively. The transmissivity and storage coefficient values of Wasia aquifer ranges from 6.7x10-3 to 8.5x10-2 m2/day and 2x10−4 to 2.3x10−4 respectively. The model calibration involved altering the values of model input parameters to match field conditions within certain acceptable limits to forecast the aquifer response over a period of 35 years (2015-2050). The modelling grid consisted of 20 and 24 columns with the grids spacing of 4 km for the small grids and 6 km for large grids. The results showed that though the Wasia aquifer was productive, it showed a large decline in water levels if water abstraction continued at the present rate. If the existing trends of groundwater withdraw continues; the piezometric heads in Wasia and Biyadh aquifers will decline by the year 2050. A reduction in 25% of the existing groundwater pumping rate in the well field will minimize the rate of groundwater decline in the aquifer to a considerable extent.

Groundwater Effect Factors for the Load-Carrying Behavior of Footings From Hydraulic Chamber Load Tests

Abstract The presence of groundwater level (GWL) causes changes in stiffness and strength of soil, affecting the bearing capacity and settlement of shallow foundations. In the present study, the load-carrying capacity and settlement of footings in sands under various GWL conditions were investigated. For this purpose, a series of model footing load tests and cone penetration tests (CPTs) were conducted using the hydraulically controlled chamber system. Different GWL and soil conditions were considered in the tests. The load-carrying capacity of footings became lower with increasing GWL, which was most significant within the depth of GWL (dw) equal to footing width (1.0B). Larger reductions in the bearing capacity with GWL were observed for looser soils with lower relative density. Based on the test results, design equations and correlation parameters for the GWL effects on the bearing capacity and settlement were proposed as a function of GWL, applied load, and relative density. It was confirmed that the existing CPT-based correlations to footing bearing capacity are valid and applicable for soils with GWL.

Effects of deficit irrigation and groundwater depth on root growth of direct seeding rice in a column experiment

Rice is an essential crop in Iran that is grown mostly in areas where depth to groundwater is low. Root growth and water uptake of rice under shallow groundwater has not been thoroughly studied. This experiment was conducted to determine the lowland rice (cv. Ghasrodashti) root distribution above shallow groundwater in relation to deficit irrigation and groundwater depth in cylindrical greenhouse lysimeters. The irrigation treatments were continuous flood irrigation (CFI) and intermittent flood irrigation (4- and 8-day intervals IF-4 and IF-8). The groundwater depths (GWD) were 0.3, 0.45 and 0.6 m from the soil surface. In general, 40-60% of root dry weight was observed in the top 10 cm of soil in CFI treatments and IF-4 with 0.3 m GWD resulted in 20% increase in root dry weight in 10-20 cm layer compared with 0-10 cm. However, the root dry weight in 0-10 cm at 0.60 m GWD was 58% lower in intermittent irrigation compared to CFI. There was no significant difference in mean root length density in IF-4 with 0.3 m GWD compared with CFI. In general, lowland rice showed good ability to develop its root system in shallow groundwater level conditions in order to extract water due to lower soil water content in the intermittent flood irrigations. Simple equations were presented to predict the groundwater contribution to evapotranspiration based on the root length density and root weight density. Therefore, in areas with shallow groundwater depth (up to 0.45 m from the soil surface) and low potential evapotranspiration, application of IF-4 instead of CFI can be useful management especially where water scarcity is a serious problem.

터널 굴착 및 가물막이 시공에 따른 주변 지하수계 유동분석

본 연구는 A호와 B호를 연결하는 도수로터널 굴착 및 가물막이 공사가 주변 지하수계에 미치는 영향을 정량적으로 평가하고자 수행하였으며, 이를 통해 인근 지하수 환경 변화 예측 및 터널의 라이닝 타설에 대한 효과를 검토하였다. 그 결과 터널 굴착 및 가물막이 공사기간 동안 터널 갱구부에서 최대 3.58 m의 지하수위 강하가 나타났으며, 터널 완공 및 라이닝 타설 시공 후 약 2년 경과 시점에서 자연상태 지하수위의 최대 90 %까지 회복하는 것으로 모사되었다. 터널 굴착에 따른 터널 내 지하수 유입량은 주향이동단층과 접하는 구간에서 터널의 배수설계기준을 초과하는 것으로 분석되었다. 이후 터널의 라이닝 타설이 완료된 후 지하수 유입량은 최대 <TEX>$0.006m^3/min/km$</TEX>로 감소하여, 라이닝 타설에 의한 효과는 93 % 이상으로 평가되었다. 또한 공사로 인한 인근 지역의 지하수 환경에 대한 분석 결과 민가, 사찰 및 견사 등에서 약 0.04~0.31 m의 수위강하가 발생하였으며, 이는 연구지역 인근에 위치한 국가지하수관측소의 연간 수위 변동량(1.3 m)의 24 %에 해당하는 수치로 분석되었다. This study is to quantitatively evaluate the impact on surrounding groundwater of waterway tunnel excavation and cofferdam construction in which A-dam and B-dam, so prediction of groundwater fluctuation and tunnel lining installation was studied. As a result, drawdown of groundwater level during tunnel excavation and cofferdam construction occurred about 3.58 m in the tunnel shaft. The initial condition of groundwater level recovered by up to 90 % was simulated after the completed the construction of the tunnel and lining installation. Groundwater inflow in the tunnel evaluated was analyzed to have exceeding water design criteria of the tunnel. The groundwater inflow is reduced to maximum <TEX>$0.006m^3/min/km$</TEX> after lining installation done in the tunnel, so effect of lining installation was evaluated as 93 % or more. Drawdown of about 0.04~0.31 m occurs in the houses and temples analysis of groundwater system of the surrounding area from construction. Drawdown has occurred nearly by considering annual groundwater level fluctuation of National Groundwater Observation Network.

A conceptual semidistributed model of the Coulazou River as a tool for assessing surface water–karst groundwater interactions during flood in Mediterranean ephemeral rivers

This study aims to assess surface water–karst groundwater interactions during floods in the Mediterranean karst watershed of the Coulazou River (southern France) using a conceptual semidistributed model at 5 min time steps. The kinematic wave routing approximation is used for the transfer of surface flow, while overflows from a linear underground reservoir account for karst flows along the riverbed. After calibration, values of parameters and simulated time series are compared to independent physical measurements. Results show that direct runoff can be neglected on the karst terrains. In addition, this study demonstrates that, in some cases, karst watersheds can be considered as relatively poor systems of regulation but strong systems of amplification or generation of floods and flash floods, depending on rainfall characteristics and also on groundwater level conditions prior to the flood event. Considering that the flood peak is the most important factor defining flash flood hazard, it is shown that the flood hazard regulation effect of the karst is relatively limited for low water table conditions prior to the flood, while the aggravating effect for high water table conditions may be higher than 80% with respect to expected values from surface runoff only. These results show that understanding groundwater–surface water interactions is crucial for describing the flash flood dynamics in karst terrains.

Influence of measurement conditions on depth range and resolution of GPR images: The example of lowland valley alluvial fill (the Obra River, Poland)

Abstract There are many studies referring to the analysis of alluvial deposit structures using GPR (ground-penetrating radar). However, the geophysical surveys are usually conducted at a single set of land surface and groundwater level conditions. The main question is whether an optimal set of such conditions resulting in optimal (highest possible) resolution and depth range can be determined? A field experiment, based on the GPR surveys conducted at various groundwater levels and parameter settings, was carried out to study their influence on depth range and resolution of the GPR surveys. The test was conducted in the lower course of the Obra River (western Poland). Three sets of the GPR measurements were done: at low groundwater level, at the groundwater level situated close to the land surface and when the surface of the floodplain was inundated and frozen. The results indicated significant differences in the depth range and resolution of particular surveys. The GPR images from the survey conducted on the frozen floodplain featured low depth range in comparison with the remaining experimental measurements. Despite the smooth surface of the frozen floodplain that seemed suitable for the geophysical surveys, the images were obscured by numerous reverberations originating from a layer of water underlying the ice cover. The presented results are the first step to create an atlas of georadar images illustrating various depositional environments. The research showed that such a database should consist of GPR images illustrating given sedimentary environment by at least three different sets of hydrogeologic conditions and GPR measurement settings taking into account such parameters as e.g. time window, number of stacks or sampling frequency.

Springs on Ljubljana polje and Barje area, significant for quantity and quality condition of the groundwater body (Slovenia)

The intergranular aquifer of Ljubljana Field and the aquifer system of Ljubljana Moor are the most important sources of drinking water for Ljubljana. The springs that appear on the area of both groundwater bodies reflect the groundwater status, quantity and quality. The spring water in the Ljubljana Field appears on vowel change of the gravel terrace. We follow them in the lower part of Ljubljana Field aquifer from Fužine to confluence of rivers Sava and Ljubljanica. The spring water directly indicates the condition of groundwater level and the quality. On the Ljubljana Barje there are important springs on the Southern edge. These springs are crucial observation point for the quality and quantity status monitoring of the inflow fro main recharge area of Ljubljana Moor aquifers that are exploited for the water supply system By the detailed analysis of older sporadic measurements of springs in Ljubljana Polje and Ljubljansko barje we were able to assess the changes in theirs trends of quantity and to design the monitoring network of springs that would acquire adequate data for the actual and future assessment of quantity an quality of these groundwater bodies in the frame of all other available and representative observation points.

Water and Salt Distribution in a Field Irrigated with Marginal Water under High Water Table Conditions

Development of an impermeable layer at some depth beneath the soil surface and the presence of a high groundwater level are common phenomena in the Yizre'el Valley, Israel. The main objective of this study was to determine the salt and water distributions and salt leaching in a field irrigated by sprinklers, under nonisotropic and high groundwater level conditions. A field experiment was conducted in a cornfield (Zea mays L.) on a Vertisol (Typic Chromoxerets) with subsurface drains. The electrical conductivity (EC) of the irrigation water was 2.5 dS m−1 The variations in water table level, in EC of soil solution and soil saturation paste, and in gravimetric water content along the field were determined at different times. Likewise, corn yield from various sites across the field was determined at the end of the growing season (August). The water table level increased sharply in the winter to 49.5 m, and then decreased continuously in the summer despite the irrigation. The EC increased in the downhill direction, more sharply in the deeper soil layers. In the upper part of the field, the average EC in saturation paste in the 0- to 1.2-m soil layer was 1.1 dS m−1 in March (end of the rainfall season) and 2.1 dS m−1 in August. Conversely, in the lower part of the field, the ECs in March and August were 4.4 and 3.7 dS m−1, respectively. A linear reduction of the corn yield with increasing EC was observed. The relatively low level of the groundwater at the upper part of the field allowed vertical salt leaching by the rainfall. Conversely, the rise of the saline (EC ≈20 dS m−1) groundwater in the lower part of the field in the winter with lateral salt movement increased the soil EC. Decline of the water table in the latter part in the summer allowed vertical leaching of salt by the irrigation water.