Lowering Of Groundwater Level Research Articles

Analysis of changes of impervious surface area in Ho Chi Minh City and Ba Ria - Vung Tau province

Rapid urban growth causes the increase of impervious surface which was converted from vegetation land. This affects the rate of water penetration into soils, the rise of surface runoff, and the lowering of groundwater levels. The expansion of the impervious surface gives rise to a series of changes in the physical environment, affecting the quality of life of people due to a change in the thermal energy balance. Therefore, the purpose of this study is to analyse of changes of impervious surface area Ho Chi Minh City and Ba Ria - Vung Tau province which is the marine national economic hub in the period of 2009-2020 by using Landsat satellite image data. The main methods used are NDWI, PISI indices and ISODATA algorithm. The results show that the area of impervious surface area of Ho Chi Minh City is very high with 18.5% in 2009 and 35% increasing rate from 2009-2020. There are 75% districts in Ho Chi Minh city having over 50% impervious surface area. Ba Ria-Vung Tau has lower impervious surface area with 5.8% in 2009 but having the incredible increasing rate– over 100%.

Effects of climate anomaly on rainfall, groundwater depth, and soil moisture on peatlands in South Sumatra, Indonesia

Climate anomalies can cause natural disasters such as severe fires and floods on peatlands in South Sumatra. Factors that affect the natural disasters on peatlands include rainfall, groundwater level, and soil moisture. This paper aims to study the effect of the climate anomalies in 2019 and 2020 and effects of these influencing factors on peatlands in South Sumatra. The data used in this study was derived from in-situ measurement at two SESAME’s measurement stations in the study area. The results indicate that in the 2019 dry season, the rainfall was minimal, the lowest groundwater table depth was −1.14 m and the lowest soil moisture was 3.4%. In the 2020 dry season, rainfall was above the monthly average of 100 mm, the lowest groundwater level was −0.44 m, and the lowest soil moisture was 26.64%. There is also a strong correlation between soil moisture and groundwater table depth. The correlation between the two is stronger when there is less rainfall.

Cross-sectoral impacts of the 2018–2019 Central European drought and climate resilience in the German part of the Elbe River basin

The 2018–2019 Central European drought was probably the most extreme in Germany since the early sixteenth century. We assess the multiple consequences of the drought for natural systems, the economy and human health in the German part of the Elbe River basin, an area of 97,175 km2 including the cities of Berlin and Hamburg and contributing about 18% to the German GDP. We employ meteorological, hydrological and socio-economic data to build a comprehensive picture of the drought severity, its multiple effects and cross-sectoral consequences in the basin. Time series of different drought indices illustrate the severity of the 2018–2019 drought and how it progressed from meteorological water deficits via soil water depletion towards low groundwater levels and river runoff, and losses in vegetation productivity. The event resulted in severe production losses in agriculture (minus 20–40% for staple crops) and forestry (especially through forced logging of damaged wood: 25.1 million tons in 2018–2020 compared to only 3.4 million tons in 2015–2017), while other economic sectors remained largely unaffected. However, there is no guarantee that this socio-economic stability will be sustained in future drought events; this is discussed in the light of 2022, another dry year holding the potential for a compound crisis. Given the increased probability for more intense and long-lasting droughts in most parts of Europe, this example of actual cross-sectoral drought impacts will be relevant for drought awareness and preparation planning in other regions.

The partial contribution of CO2-emission losses from subsidence in small-holder oil palm plantation on a tropical peatland in West Kalimantan, Indonesia

Abstract. Astiani D, Widiastuti T, Ekamawanti HA, Ekyastuti W, Roslinda E, Mujiman. 2022. The partial contribution of CO2-emission losses from subsidence in small-holder oil palm plantation on a tropical peatland in West Kalimantan, Indonesia. Biodiversitas 23: 6539-6545. Carbon storage in tropical peat ecosystems over thousands of years, especially within peat soil, is in huge quantity. Degradation of peat ecosystems is generally caused by human factors, whether intentional or not, damaging the carbon storage function of tropical peatlands, where forest clearing, drainage development, and burning of land converted to agriculture and plantations result in significant greenhouse gas emissions. Tropical peat in the Kubu Raya District of West Kalimantan, which has a relatively large area of peat, has been degraded as a cause of uncontrolled drainage and land fires caused by a lack of management after its forest cover was lost. The main impact is an increase in peat CO2 emissions due to changes in land use, especially lowering groundwater levels. Subsequently, the subsidence process also occurs after land clearing. This study aims to obtain the proportion of carbon biomass loss due to the CO2 emission process from reducing the peat layer due to subsidence. Data collection was executed for two years, where CO2 emission was monitored bi-weekly, and the subsidence was measured bi-monthly. The results demonstrate groundwater levels dictate the peat CO2 emission and subsidence. Lowering GWL 30 to -85 cm increases CO2 by more than three times, approximately. The rate of peat subsidence shows similar trends to the emission. The proportion of peat biomass loss on CO2 emission was between 58.9 to 73.5%, except for GWL ~5 cm, where the proportion was the highest at 82%. The results of this study are beneficial in explaining the part of the subsidence that impacts the sources of CO2 emissions from the small-holder oil palm and GWL management on peatlands.

Control and prevent land subsidence caused by foundation pit dewatering in a coastal lowland megacity: indicator definition, numerical simulation, and regression analysis

Land subsidence has to be controlled under global climate change and sea level rising for coastal megacities. Land subsidence caused by lowering groundwater level during underground excavation has become a dominant influence factor for land subsidence during urbanization and city renewal. How to manage the land subsidence induced by foundation pit dewatering (FPD) on an urban scale was urgent. Shanghai was selected as the research background. A subsidence and drawdown double control (SDDC) partition was established. The position of three times excavation depth (3H) horizontally away from the foundation boundary in the plane was defined as the boundary between dewatering subsidence and excavation settlement. Land subsidence of 3H (LS-3H) and groundwater drawdown on 3H (GD-3H) were defined as the evaluating and controlling indicators. An FPD conceptual model was summarized by the estimating and investigating of foundation pit information and numerical simulations were performed. A total of 6540 FPD scenarios were simulated for the LS-3H and GD-3H. Multi-factor regression analysis was conducted to obtain relations between the GD-3H and the shape, area, depth, and curtain depth of foundation pit on the basis of the numerical simulations. The regression models can be used to estimate the GD-3H and compared with the threshold specified by land subsidence prevention and control (LSPC) law, which can provide a reference for similar cases.

Teaching practice of artificially lowering groundwater level in the course of hydraulic engineering construction

The course of hydraulic engineering construction involves many contents, wide scope and short class hours, and teachers often do not have enough time to teach many knowledge points that need to be mastered in practical projects, among which the knowledge point of "artificially lowering groundwater level" has this characteristic.Based on tube-well method and well-point method, this paper designs the teaching path based on the concept of case teaching method, and makes use of effect drawings, engineering drawings, PPT animation, FLASH animation and engineering cases in limited class hours to make students understand the basic principles, technical characteristics, scope of application, design and calculation of these two0 methods. Finally, the students can initially master the calculation of the displacement of foundation pit, the number and layout of pipe wells in artificially lowering groundwater level, and have the preliminary ability of engineering practice.

Soil CO2 and CH4 fluxes from different forest types in tropical peat swamp forest

Information on temporal and spatial variations in soil greenhouse gas (GHG) fluxes from tropical peat forests is essential to predict the influence of climate change and estimate the effects of land use on global warming and the carbon (C) cycle. To obtain such basic information, soil carbon dioxide (CO2) and methane (CH4) fluxes, together with soil physicochemical properties and environmental variables, were measured at three major forest types in the Maludam National Park, Sarawak, Malaysia, for eight years, and their relationships were analyzed. Annual soil CO2 fluxes ranged from 860 to 1450 g C m⁻2 yr⁻1 without overall significant differences between the three forest sites, while soil CH4 fluxes, 1.2–10.8 g C m⁻2 yr⁻1, differed. Differences in GHG fluxes between dry and rainy seasons were not necessarily significant, corresponding to the extent of seasonal variation in groundwater level (GWL). The lack of significant differences in soil CO2 fluxes between the three sites could be attributed to set-off between the negative and positive effects of the decomposability of soil organic matter as estimated by pyrophosphate solubility index (PSI) and GWL. The impact of El-Niño on annual CO2 flux also varied between the sites. The variation in soil CH4 fluxes from the three sites was enhanced by variations in temperature, GWL, PSI, and soil iron (Fe) content. A positive correlation was observed between the annual CH4 flux and GWL at only one site, and the influence of soil properties was more pronounced at the site with the lowest GWL and the highest PSI. Variation in annual CH4 fluxes was controlled more strongly by temperature where GWL was the highest and GWL and plant growth fluctuations were the least. Inter-annual variations in soil CO2 and CH4 fluxes confirmed the importance of long-term monitoring of these at multiple sites supporting different forest types.

Degradation of wood buried in soils exposed to artificially lowered groundwater levels in a laboratory setting

Service life of wooden foundation piles could be at risk during modern urban construction work, as local groundwater conditions might change and cause increased degradation of nearby buried wood material. Maintaining a high groundwater level has been linked to good preservation conditions, but detailed studies on the effect of lowering the water level have not yet been performed. In this unique designed laboratory study, we explore how reduced water levels affect degradation rates of wood rods embedded in clay soil. In clay columns, effects of reduced water levels (30 cm, 60 cm) and fluctuating water levels (0–60 cm) were investigated at three levels (−5 cm, −30 cm, −55 cm). Two controls were included, one with no water reduction and one with sand soil. Redox potential was measured regularly at the three levels, and soil moisture was measured at start and end of experiment (12 months). Results showed that lowering water levels generally increased wood degradation. Decay took place almost exclusively by soft rot fungi and was highest at −5 cm below soil surface. At −55 cm depth and −400 mV redox potential, scarcely any decay was observed. Desiccation was highest in sand and in clay with −60 cm water reduction, and any decay process here had stopped. Surprisingly, fluctuating water level generated equally low decay rates as a high stable water level. Covered soil surfaces yielded less degradation and the effect was even comparable to that of a maintained high groundwater level. Protecting soils against desiccation could thus keep wood degradation at a minimum at open-air excavations. More experiments are needed to determine long-term effects and threshold values for decay in relation to redox potential.

INFLUENCE OF ENGINEERING PROPERTIES OF SOILAND GROUNDWATER MOVEMENT ON GULLY DEVELOPMENT IN RAFINGORA, NORTHERN BIDA BASIN, NIGERIA

The formation and expansion of gullies in Rafingora community, northern sector of the Bida Basin, Nigeria was investigated. This was aimed at determining the controlling factors for gully development in the area, using field gully parameter measurements, hydrogeological mapping and geotechnical investigation of soils from gully sites. U-shaped gullies were mapped with sliding, slumping and block fracturing as the main modes of gully propagation. Relief is gentle; slope angles range from 1.58° to 1.96°, indicating little or no influence of elevation on gully development. Gullies were found to be deeper than 3m, with drainage area of more than 30m. Depth to water in open wells ranges from 5.5m in the north-eastern part to about 16.4m in the south-western part. Gullies in the north-eastern side are mostly shallower than the water table, contrary to the situation in the south-western part. This shows a direct relationship between water table elevation and gully propagation and is further exacerbated by the relatively high average hydraulic of soils. The soils have low plasticity, cohesion, angle of internal friction (AIR) and maximum dry density (MDD). A combination of these poor geotechnical properties makes the soils friable and crumbles easily when in contact with water and offers very little resistance to erosion. Conclusively, gully development in Rafingora is influenced more by bottom erosion due to high hydraulic conductivity and seepage forces, rather than by overland runoff. Reclamation attempts may consider lowering groundwater levels as a major strategy for erosion control in the area.

Using machine learning algorithms to predict groundwater levels in Indonesian tropical peatlands

Tropical peatlands play a vital role in the global carbon cycle as large carbon reservoirs and substantial carbon sinks. Indonesia possesses the largest share (65 %) of tropical peat carbon, equal to 57.4 Gt C. Human perturbations such as extensive logging, deforestation and canalization exacerbate water losses, especially during dry seasons, when low precipitation and high evapotranspiration rates combine with the increased drainage to lower groundwater levels. Drying and increasing temperatures of the surface peat exacerbate ignition and wildfire risks within the peat soils. As such, it is critically important to know how groundwater levels in peatlands are changing over space and time. In this study, a multilinear regression model as well as two machine learning algorithms, random forest and extreme gradient boosting, were used to model groundwater level over the study period (2010−12) within a peat dome impacted by drainage canals and multiple wildfires in Central Kalimantan, Indonesia. Although all three models performed well, based on overall fit, spatial modeling of groundwater level results revealed that extreme gradient boosting (R2 = 0.998, RMSE = 0.048 m) outperformed random forest (R2 = 0.997, RMSE = 0.054 m) and multilinear regression (R2 = 0.970, RMSE = 0.221 m) near drainage canals, which are key fire ignition risk locations in the peatlands. Our study also shows that, on average, elevation and precipitation are the most important parameters influencing groundwater level spatiotemporally.

Potential role of high-altitude wetlands in preservation of plant biodiversity under changing climatic conditions in the arid Eastern Pamir

High-altitude wetlands in the Eastern Pamir are habitat islands located in an arid landscape. They play several important roles, including that of water sources and forage grounds for people and their livestock. Considering high variation in micro-relief and complexity of water supplies observed in these wetlands, we assessed their potential to play a role of refugia for species whose present ranges may be limited by climate changes projected for Central Asia. Such species currently occur typically in less moist habitats, often located at lower elevations (e.g. steppe and meadow species). To perform this assessment, we analyzed current spatial structure and species diversity of vegetation accompanying selected water bodies in the studied catchments, identified present changes in temperature and precipitation in these catchments and analyzed alterations in area of lakes and small water bodies located in the vegetation mosaic. Presently, the biodiversity of the studied wetlands comprises 110 species of vascular plants from 26 families, forming ten distinct vegetation types, over 40 recorded species are typical for steppes and various types of alpine meadows. Both meteorological data and satellite data on open water area indicated that with growing temperatures, areas of the studied lakes and small water bodies in the vegetation mosaic increase. This effect is probably caused by thawing of ground ice and permafrost, whose occurrence helps mitigate the effects of the ongoing warming and lessening precipitation. Thus, the wetlands may temporarily maintain their cold, wet and mesic characteristics under the changing climatic conditions and, as such, potentially become refugia for steppe and meadow species. However, after the period of intense thawing, lowering of groundwater level and huge surface water fluctuations may occur, potentially resulting in a decrease in the total vegetated area on lacustrine and riverine terraces in the Eastern Pamir.

Response of the fine root morphological and chemical traits of Tamarix chinensis to water and salt changes in coastal wetlands of the Yellow River Delta.

To explore the adaptation of the fine root morphology and chemical characteristics of Tamarix chinensis to water–salt heterogeneity in the groundwater–soil system of a coastal wetland zone, T. chinensis forests at different groundwater levels (high: GW1 0.54 m and GW2 0.83 m; medium: GW3 1.18 m; low: GW4 1.62 m and GW5 2.04 m) in the coastal wetland of the Yellow River Delta were researched, and the fine roots of T. chinensis standard trees were excavated. The fine roots were classified by the Pregitzer method, and the morphology, nutrients, and nonstructural carbohydrate characteristics of each order were determined. The results showed that the groundwater level had a significant indigenous effect on the soil water and salt conditions and affected the fine roots of T. chinensis. At high groundwater levels, the specific root length and specific surface area of fine roots were small, the root tissue density was high, the fine root growth rate was slow, the nutrient use efficiency was higher than at low groundwater levels, and the absorption of water increased with increasing specific surface area. With decreasing groundwater level, the N content and C/N ratio of fine roots first decreased and then increased, and the soluble sugar, starch, and nonstructural carbohydrate content of fine roots first increased and then decreased. At high and low groundwater levels, the metabolism of fine roots of T. chinensis was enhanced, and their adaptability to high salt content and low water content soil environments improved. The first- and second-order fine roots of T. chinensis were mainly responsible for water and nutrient absorption, while the higher-order (from the third to fifth orders) fine roots were primarily responsible for the transportation and storage of carbohydrates. The fine root morphology, nutrients, nonstructural carbohydrate characteristics, and other aspects of the water and salt environment heterogeneity cooperated in a synergistic response and trade-off adjustment.

DEFORESTATION AND BIODIVERSITY DEGRADATION IN MADHUPUR SAL FOREST AT TANGAIL REGION

The study was conducted to investigate the deforestation and biodiversity degradation in Madhupur sal forest of Tangail region during April to September 2010. Households from different garo villages of two selected unions under the forest were contacted for interview to identify the resource consumption pattern and to know their views about deforestation and biodiversity degradation in the forest. Various commercial activities such as large scale plantation of pineapple, banana and papaya trigger the environmental degradation inside the forest through many ways therefore degrading the remaining forest patches, soil quality of the forest and reducing the forest biodiversity. Most of the respondents mentioned that major causes for biodiversity loss including deforestation followed by commercial logging, loss of habitat and lack of conservation initiatives. Results of the study suggested that restriction on human interference inside the forest is the effective solution for reducing deforestation and biodiversity degradation. The study identified that the loss of biodiversity in the forest depended on the effect of deforestation, threats to indigenous livelihood, enhanced greenhouse effect, lowering ground water levels and soil erosion, respectively.

An ensemble approach for predicting future groundwater levels in the Zagreb aquifer impacted by both local recharge and upstream river flow

This paper presents the first study assessing the climate change impact on groundwater levels of the Zagreb alluvial aquifer in Croatia by coupling climate projections under RCP8.5 for the period 2040–2070 with local scale groundwater flow modelling. As a novelty in groundwater modelling of climate change impacts, this study utilizes an ensemble of five climate models and two land surface models for providing projections of relevant boundary conditions to the groundwater model. The groundwater model is used for predicting climate driven changes in groundwater levels in the aquifer system influenced by both changes in local groundwater recharge and changes in river-flow. Both boundary conditions are obtained from the land surface models. In addition, the uncertainty contributions to groundwater levels from both climate models and land surface models were quantified using variance decomposition. The results revealed that the spatial pattern of changes in groundwater levels can be related to different processes influencing groundwater dynamics. In areas dominated by a strong groundwater-surface water interaction, close to the Sava river, the multi-model ensemble mean change in groundwater levels is negligible for low and average water levels. However, for high water levels, an increase was identified. In contrast, a decline in groundwater levels prevails in all areas where aquifer recharge is largely driven by rainfall infiltration. For the variance decomposition analysis, climate models were identified as the main source of uncertainty for groundwater levels. However, the uncertainty contribution of the choice of land surface model to the impact simulations was found to be more important in the area affected by a strong groundwater–surface water interaction and for periods of high groundwater levels. Also, specific local issues related to low and high groundwater levels that are associated with extreme hydrological regimes were found to exacerbate under climate projections.

Ameliorative Effect of Tamarindus indica and Vitamin D Supplementation On Fluoride Induced Biochemical Parameters in Albino Rat

Fluoride water problem is very common in all areas of world including India. The deleterious effects of fluoride on bones causes fluorosis. This problem arises mainly due to gradual lowering of ground water level, which is merely responsible for degrading water quality. The hand pumps of many areas are restricted for use due to excess fluoride in their water. In a country like India, it is very tough to provide pure drinking water to all. Hence this study is designed to study the effect of fluoride on biochemical parameters in albino rats, the mammalian model. The aim and objective of this study is to evaluate combination of two antioxidants viz. Tamarindus indica (rich source of vitamin C) and vitamin D against fluoride toxicity in mammals for which albino rat is used as model. Tamarindus have significant amount of antioxidants and vitamin D also have immunity and healing properties, hence this can be a reason behind their cumulative ameliorative effect against sodium fluoride intoxication. Further, the effect of fluoride can be minimized or ameliorated using some antioxidants and vitamins. For this purpose, the fluoride intoxicated rats were observed for possible amelioration by Tamarindus indica and vitamin D supplementation. The fluoride intoxication showed altered biochemical parameters like serum protein, SGOT, SGPT, ACP, ALP and LDH

Numerical evaluation of a 70-m deep hydropower station foundation pit dewatering

The foundation pit of Yamansu hydropower station has an average depth of 70 m and has been excavated with five-level slopes. Lowering of groundwater level is important in excavation. In this study, drainage and pumping were conducted in dewatering. Pumping tests were performed to reverse hydraulic parameters and calibrate numerical models. Numerical simulations were performed to evaluate the dewatering scheme. In the first stage, powerhouse tailrace canal was excavated and used as a drainage channel to lower the groundwater level. Drawdown and hydraulic gradient were evaluated to prevent potential water inrush, erosion, piping, and slope failure. In the second stage, cutoff wall and pumping wells were evaluated to reduce the groundwater level. The influences of depth, permeability, and thickness of the cutoff wall were evaluated. Dewatering scheme was revised accordingly based on the evaluation. The optimized dewatering scheme, which can be used as a reference in similar engineering projects, was performed and verified successfully.

Ecological regimes of soils of the Novgorod region drained by open drainage

In the natural and climatic conditions of the Novgorod region, the ecological regimes of lands drained by various open drainage structures were studied: channels through 70 m (control), runoff hollows in combination with the strips of cultivation, reclamation, and closed drainage. During the operation (1992-2021) of open drainage structures, the agrochemical state of soils changed: the exchange acidity decreased; the humus content increased by 2-3 %, with the exception of a combination of hollows with a reclamation strip (a decrease of 1.5 %); the content of mobile phosphorus and potassium decreased. The formation of groundwater regimes and moisture reserves on drainage systems depends on meteorological conditions, which in the last 5 years have been very diverse: from slightly arid (2020, HTC = 1.1) to excessively moist (2017, HTC = 2.65). The systems of runoff hollows in combination with the reclamation strip provided the lowest groundwater level, while in an extremely wet year they did not rise into the arable horizon. The most favorable moisture regime of the root-inhabited soil layer in excessively humid 2017 and subsequent years was noted on systems of runoff hollows with closed drainage in combination with reclamation strips. During dry periods, which are usually June-July, a lack of moisture in the root layer of the soil was observed on experimental systems of runoff hollows in combination with cultivation and reclamation strips. The most acute moisture deficiency in these periods (0.45 full capacity) was noted on systems combining runoff hollows with cultivation strips. The most favorable soil moisture regime (0.65-0.85 full capacity) was in the combination of hollows with closed drainage and a reclamation strip. The formed new ecological regimes of the soils drained by the hollow-strip method had a significant impact on the hay yield of perennial grasses (Phleum pratense, Festuca pratensis). The increase in yield compared to the control averaged 0.3-0.6 t/ha over 5 years.

Influence of low-frequency variability on high and low groundwater levels: example of aquifers in the Paris Basin

Abstract. Groundwater levels (GWLs) very often fluctuate over a wide range of timescales (intra-annual, annual, multi-annual, and decadal). In many instances, aquifers act as low-pass filters, dampening the high-frequency variability and amplifying low-frequency variations (from multi-annual to decadal timescales) which basically originate from large-scale climate variability. Within the aim of better understanding and ultimately anticipating groundwater droughts and floods, it appears crucial to evaluate whether (and how much) the very high or very low GWLs are resulting from such low-frequency variability (LFV), which was the main objective of the study presented here. As an example, we focused on exceedance and non-exceedance of the 80 % and 20 % GWL percentiles respectively, in the Paris Basin aquifers over the 1976–2019 period. GWL time series were extracted from a database consisting of relatively undisturbed GWL time series regarding anthropogenic influence (water abstraction by either continuous or periodic pumping) over metropolitan France. Based on this dataset, our approach consisted in exploring the effect of GWL low-frequency components on threshold exceedance and non-exceedance by successively filtering out low-frequency components of GWL signals using maximum overlap discrete wavelet transform (MODWT). Multi-annual (∼7-year) and decadal (∼17-year) variabilities were found to be the predominant LFVs in GWL signals, in accordance with previous studies in the northern France area. By filtering out these components (either independently or jointly), it is possible to (i) examine the proportion of high-level (HL) and low-level (LL) occurrences generated by these variabilities and (ii) estimate the contribution of each of these variabilities in explaining the occurrence of major historical events associated with well-recognized societal impacts. A typology of GWL variations in Paris Basin aquifers was first determined by quantifying the variance distribution across timescales. Four GWL variation types could be found according to the predominance of annual, multi-annual, or/and decadal variabilities in these signals: decadal-dominant (type iD), multi-annual- and decadal-dominant (type iMD), annual-dominant (type cA), and annual- and multi-annual-dominant (type cAM). We observed a clear dependence of high and low GWL on LFV for aquifers exhibiting these four GWL variation types. In addition, the respective contribution of multi-annual and decadal variabilities in the threshold exceedance varied according to the event. In numerous aquifers, it also appeared that the sensitivity to LFV was higher for LLs than HLs. A similar analysis was conducted on the only available long-term GWL time series which covered a hundred years. This allowed us to highlight the potential influence of multidecadal variability on HLs and LLs too. This study underlined the key role of LFV in the occurrence of HLs and LLs. Since LFV originates from large-scale stochastic climate variability as demonstrated in many previous studies in the Paris Basin or nearby regions, our results point out that (i) poor representation of LFV in general circulation model (GCM) outputs used afterwards for developing hydrological projections can result in strong uncertainty in the assessment of future groundwater extremes (GWEs), and (ii) potential changes in the amplitude of LFV, be they natural or induced by global climate change, may lead to substantial changes in the occurrence and severity of GWEs for the next decades. Finally, this study also stresses the fact that due to the stochastic nature of LFV, no deterministic prediction of future GWEs for the mid- or long-term horizons can be achieved, even though LFV may look periodic.

Delineation of Groundwater Potential Zones in Koyna River Watershed, Maharashtra using Remote Sensing and GIS

Groundwater is considered as only source which provides water for meeting domestic, industrial and agricultural requirement. Continuous uses of water without any conservation cause lowering of Ground water level and thus living forms are facing many problems now-a-days. In current situation some existing wells getting dried up because of depletion of groundwater table as the natural groundwater recharge is not sufficient for requirements. As a result, the access to resources and their demand allows individuals to pick favorable locations for population increase. As the world’s population grows, so does urbanization and groundwater exploration. As a rising metropolitan region, it is critical to analyze the present groundwater scenario of the Koyna River watershed. This study is simple to do with the use of remote sensing and geographical information systems (GIS) by cost-effectively incorporating factors impacting groundwater potential. We will combine numerous data sets and maps in this study, including satellite imaging, drainage, groundwater level, precipitation, LULC, slope, and its existing geological map. After including the groundwater potential, it was divided into five distinct zones: extremely poor, poor, moderate, good, and very excellent [1].

Development of different hydrogeological influencing thematic layers and groundwater potential zones of Deo river watershed of Mayurbhanj district, Odisha, India

Water is one of the most abundant renewable resources, and it is essential to all living things. Groundwater is one of the major sources of Water in the planet Earth. Continuous uses of water without any conservation cause lowering of Ground water level and thus living forms are facing many problems now-a-days. Due to increase in industrialisation in the state of Odisha water problem is rising its head. Using Remote Sensing and Geographic information system (GIS) methods, this research aids in the delineation of water potential zones in the Deo river watershed in Mayurbhanj district, odisha. For this, different thematic layers have been prepared and interpreted. This study may be helpful to monitor and conserve groundwater in near future.