Groundwater Trends Research Articles

Assessing the Effects of Wheat Planting on Groundwater Under Climate Change: A Quantitative Adaptive Sliding Window Detection Strategy

Climate change has led to changes in precipitation patterns, exacerbating the overextraction of groundwater for wheat irrigation. Although many studies have examined the effects of wheat cultivation on groundwater storage (GWS), few studies have directly assessed the effects of wheat planting on GWS. We proposed a wheat subsiding effect detection (WSED) strategy using time-series remote sensing image to assess the effect of wheat area on GWS across China. The subsiding magnitude of the WSED is calculated as the GWS difference between the wheat area and adjacent nonwheat area in the self-adaptive moving window (the size and position of the sliding window can be automatically adjusted based on the characteristics of the data at the central pixel location). The effects of the wheat area on groundwater storage differ greatly among the change types of wheat area and planting regionalization, characterized by the strong subsiding effect in the wheat stable area, gain area, and Huanghuaihai zone (HWW, the most important wheat-producing region in China mainly includes the provinces and municipalities of Beijing, Tianjin, Henan, Hebei, Shandong, Anhui, and Jiangsu). Nearly 80% of the wheat area in the stable and gain regions had lower groundwater depth than nonwheat areas with significant differences (p < 0.05), resulting in a clear declining groundwater trend of approximately −1 cm/year. This study provides quantitative evidence for the effects of wheat planting on GWS regarding agricultural production and climate change adaptations.

Trend analysis and learning-based groundwater level modelling over a tropical river basin

Groundwater trend analysis and modeling is challenging due to partially explicable factors and unexplained human influence. Hurst index, Sequential Mann-Kendall, and Classical Mann-Kendall test offers a comprehensive groundwater trend analysis. A learning-based approach is developed to model groundwater levels using climatological variables of rainfall and temperature. The study is on 24 locations over Periyar river basin of Kerala, India, for the years 1996-2019, and during January, April, August, and November (JAAN) months. The significant trends were observed at 14 locations in at least one of the JAAN months, which is about 58%. Out of these, 8 locations exhibited positive trend signaling a decline in groundwater supplies. The developed model yielded notable improvements in precision with 50%, 79%, 75% and 83% of the locations in month-wise order. To gauge the model performance, observed and predicted location clusters obtained using k-means clustering are juxtaposed for the years 2017-2019, on both individual and average basis. This assessment indicated only one well transitioning in August, with the average approach resulting in a closer match to the original clustering for most of the wells. These findings shall benefit future stakeholders and policymakers in optimizing resource management strategies over the basin and wider.

Historical patterns of well drilling and groundwater depth in Arizona considering groundwater regulation and surface water access

AbstractArizona has a long history of groundwater use, and there is concern about long term groundwater sustainability across the state. We explore groundwater trends across Arizona and how they vary with respect to: (1) whether groundwater pumping is regulated, and (2) relative access to local or imported surface water. Well observations from the Arizona Department of Water Resources are used to quantify water table depth trends and groundwater drilling patterns. There are more than 85,000 groundwater wells in Arizona, and new wells are routinely being drilled. The number of new shallow wells (<200 ft) has decreased over time in all parts of the state. But midrange (200–500 ft) to deep (>500 ft) wells have increased in the past 10 years in regulated and groundwater dominated areas. Most wells are small with low pumping capacities that fall below the regulatory limit; however, there are still large wells being drilled in unregulated areas. Results show statewide decreasing water storage and groundwater levels. Groundwater declines are less severe in the parts of the state that have groundwater regulation. However, looking closer at this trend, groundwater recovery is strongest in areas receiving imported Colorado River water which also implement managed groundwater recharge with the imported water. Our findings indicate that groundwater recovery is very localized and driven more by managed recharge from surface water as opposed to decreased groundwater pumping.

Long‐term trends in mountain groundwater levels across Canada and the United States

AbstractMountains have a critical role in freshwater supply for downstream populations. As the climate changes, groundwater stored in mountains may help buffer the impacts to declining water resources caused by decreased snowpack and glacier recession. However, given the scarcity of groundwater observation wells in mountain regions, it remains unclear how mountain groundwater is being impacted by climate change across ecoregions. This study quantifies temporal trends in mountain groundwater levels and explores how various climatic, physiographic and anthropogenic factors affect these trends. We compiled data from 171 public groundwater observation wells within mountain regions across Canada and the United States, for which at least 20 years of monthly data is available. The Mann‐Kendall test for monotonic trend revealed that 54% of these wells have statistically significant temporal trends (p < 0.05) over the period of record, of which 69% were negative and therefore indicating overall declining groundwater storage. Wells in the western mountain ranges showed stronger trends (both positive and negative) than the eastern mountain ranges, and higher elevation wells showed fewer negative trends than the low elevation (<400 m asl) wells (p < 0.05). Correlation, Kruskal‐Wallis tests, stepwise multiple linear regression and random forest regression were used to identify factors controlling groundwater trends. Statistical analysis revealed that lower‐elevation mountain regions with higher average annual temperatures and lower average annual precipitation have the greatest declines in groundwater storage under climate change. Trends in temperature and precipitation, and ecoregion were also important predictors on groundwater level trends, highlighting geographic differences in how mountain wells are responding to climate change. Furthermore, sedimentary bedrock aquifers showed markedly more negative trends than crystalline bedrock aquifers. The findings demonstrate that the impact of climate change on mountain water resources extends to the subsurface, with important implications for global water resources.

Assessing the Impact of Groundwater Recharge on Underground Reservoir Replenishment in Eastern Uttar Pradesh, India

Groundwater is considered a fresh resource of water and its uses have tremendously increased in the recent past due to an increase in population, rapid urbanization, and industrialization. In India, the groundwater level is declining in some parts of the country due to over-exploitation, low or negligible recharge of aquifer systems, and unsustainable development of groundwater resources. The groundwater modeling is an important tool for studying the past and present groundwater behavior and in the development of future strategies for sustainable groundwater management plans. To study the Impact of groundwater recharge on the replenishment of underground reservoir, Ballia district of Uttar Pradesh has been selected which is one of the districts of the most populous state of India, Uttar Pradesh. An attempt has been made to develop a groundwater model using Modflow software to simulate the groundwater trends and predict future groundwater heads. The calibration and validation of the model were done for 5 years and 3 years respectively. The correlation coefficient for calibration and validation was found 0.85 and root mean square errors vary from 2.89 to 3.2m variation in future trends of groundwater heads. The results of the study show that the developed model can be effectively used to predict the future groundwater heads. The groundwater flow was observed from the northwest to southeast direction. It was predicted from the study that groundwater draft will increase by 10% with a decrease in groundwater level by approximately 0.24 m in the north-west direction by the year 2025. However, no impact was observed in the south side of the district and it was predicted that the groundwater level would remain the same in this zone during the next 3 years.

Groundwater-dependent ecosystem map exposes global dryland protection needs

Groundwater is the most ubiquitous source of liquid freshwater globally, yet its role in supporting diverse ecosystems is rarely acknowledged1,2. However, the location and extent of groundwater-dependent ecosystems (GDEs) are unknown in many geographies, and protection measures are lacking1,3. Here, we map GDEs at high-resolution (roughly 30 m) and find them present on more than one-third of global drylands analysed, including important global biodiversity hotspots4. GDEs are more extensive and contiguous in landscapes dominated by pastoralism with lower rates of groundwater depletion, suggesting that many GDEs are likely to have already been lost due to water and land use practices. Nevertheless, 53% of GDEs exist within regions showing declining groundwater trends, which highlights the urgent need to protect GDEs from the threat of groundwater depletion. However, we found that only 21% of GDEs exist on protected lands or in jurisdictions with sustainable groundwater management policies, invoking a call to action to protect these vital ecosystems. Furthermore, we examine the linkage of GDEs with cultural and socio-economic factors in the Greater Sahel region, where GDEs play an essential role in supporting biodiversity and rural livelihoods, to explore other means for protection of GDEs in politically unstable regions. Our GDE map provides critical information for prioritizing and developing policies and protection mechanisms across various local, regional or international scales to safeguard these important ecosystems and the societies dependent on them.

Research on the Influence Radius on the Surrounding Groundwater Level in the Beidianshengli Open-Pit Coal Mine of China

Coal mining has a certain influence on and causes disturbances in groundwater. To investigate the variation trend of groundwater around the open-pit mine in grassland area, taking Shengli No. 1 open-pit mine as an example, the impact and variation trend of groundwater level in Quaternary aquifer around the mine area was studied by using the data of hydrological monitoring wells. The results show that the water level around the mining area varies from one year to the next. Since 2008, the water level has experienced a process of reduction, stability and increase. Compared with the background water level value, the current water level of each monitoring well is lower than the background water level. The influence radius calculated by Kusakin formula ranges from 94.15 m to 906.80 m, and the aquifer is heterogeneous. On the basis of the correlations between changes in waterline in monitoring wells and the stope distance, the disturbance radius of open-pit mining on surrounding diving water in grassland area is less than 2000 m. Based on the comprehensive analysis of the alteration of diving waterline and its influencing factors, the main factors affecting the variation in the phreatic water level are atmospheric precipitation, evaporation, groundwater usage and dewatering water. All factors act on the diversification of diving water level synthetically. The internal waste dump of an open-pit mine has a positive effect on the surrounding groundwater recovery. The aim of this study is to reveal the impact of open-pit mining on surrounding groundwater and providing scientific basis for future mining in other open-pit mines.

Analyzing water level variability in Odisha: insights from multi-year data and spatial analysis

A comprehensive analysis of long-term water level trends is essential for freshwater sustainability. Given that Odisha heavily relies on agriculture, the monitoring and management of groundwater and its fluctuations are imperative for ensuring future sustainability in the state. Here, we analyzed the trend in Groundwater using water level data for a 30-year period (1990–2020) for the entire Odisha region. Moreover, to determine the long term variability, critical zones of future groundwater variability and controlling parameters of the water level change, we used spatio-temporal water level data of 746 locations. Water level rise of coastal districts during post-monsoon (POM), corresponds to the intensity of rainfall received, thus rising, however other districts of Odisha, showing decline in water level during the same season is due to shortage of rainfall, increase in population at a sudden, and over pumping due to industrial activities. Similarly, during pre-monsoon (PRM), water level shows an increasing trend in hard rock terrain of Odisha implying rabi crop irrigation, high density drainage network and lesser population density. Feature selection techniques were used in this study to know the parameters controlling most to this water level fluctuation in the entire Odisha state. Precipitation followed by landuse & landcover, lithology and population density are controlling the most for the long term water level change. Drainage, elevation, lithology and slope are positively related to the water level change while others are negatively related. It is also inferred that the districts like Mayurbhanj, Sundargarh, Keonjhar, Kandhamal, Boudh, Dhenkanal, Gajapati, Koraput and Kalahandi contain most of the high critical zone concerning future availability of groundwater while most of the coastal regions are safe.

China's groundwater situation in 2011–2020: Dynamic evolution, Influencing Factors, and sustainable development

Groundwater plays important roles in resource security and ecological maintenance and is sensitive to changes in the natural environment and human activities. It is of paramount importance to investigate the dynamic evolution trend of groundwater and its affecting factors and sustainable development. This paper takes mainland China as the study area, using data sourced from the Groundwater Dynamic Monthly Report, the China Water Resources Bulletin, and the Provincial Water Resources Bulletin. The temporal and space-time evolution trend of groundwater depth in 2011–2020 is determined, along with the correlation between variations in groundwater resources and precipitation, the factors affecting these changes, and the sustainability of groundwater use. The results are as follows: (1) The northern and western regions of mainland China had a greater depth of groundwater compared to the southern and eastern regions. The largest groundwater depth is in the Northwest Rivers Basin (Nw RB), which can reach 17.61–21.10 m, and the shallowest groundwater depth is in the Southeast Rivers Basin (Se RB), only 1.61–5.19 m. (2) Regarding the factors affecting the changes in groundwater resources, precipitation, land use pattern, human activities, and industrial and agricultural water use are highlighted. (3) Overall, the percentage of groundwater in the total water supply has declined. The optimization of groundwater resource allocation and the adjustment of industrial structure have resulted in the coordinated utilization of groundwater resources. The research establishes a scientific foundation for ensuring national water security and promoting sustainable economic and social development.

BaHys—A Bayesian Modeling Framework for Long‐Term Concentration‐Discharge Hysteresis: A Case Study on Chloride

AbstractImproving river water quality requires a thorough understanding of the relationship between constituent concentration and water discharge during runoff events (i.e., C‐Q hysteresis), which may be strongly non‐linear. Analysis of C‐Q hysteresis on large temporal scales provides unprecedented insights into event dynamics and long‐term concentration trends in surface and groundwater. Despite the increasing availability of time series data on water quality, there are still limited quantitative modeling frameworks that enable this analysis. Here, we combine Bayesian modeling and an existing mass balance to model long‐term C‐Q hysteresis dynamics in multi‐decade constituent concentration and water discharge time series. We focus on the case study of chloride and demonstrate that our model can simultaneously characterize the size and rotation of C‐Q hysteresis, and diffuse and low‐flow inputs to constituent concentration using only time‐series data from the river Rhine. Over 28 years of monitoring, we find that chloride exhibits a dominant clockwise dilution behavior that does not vary considerably under different hydro‐climatic conditions, hinting to similar mobilization mechanisms over time. We also show decreasing chloride concentrations in surface and groundwater, due to the cessation of mining activities in the Rhine. Our approach uses uncertainty estimates to show the range within which model parameter values lie, aiding decision‐makers in a robust assessment of river water quality. We conclude that Bayesian modeling of C‐Q hysteresis provides a powerful framework for investigating long‐term contamination dynamics that can be extended to several constituents to find factors controlling their export, ultimately suggesting mitigation measures for river contamination.

Effects of inter-basin transfers on watershed hydrology and vegetation greening in a large inland river basin

The effects of inter-basin transfers (IBTs) on watershed hydrological balances and associated ecosystem processes remain poorly understood in arid regions because of data scarcity and the complexity of ecosystem responses to water management in many parts of the world. To fill this gap, the objective of this study was to quantify the effect of IBTs on watershed hydrological regimes and the associated vegetation dynamics. We conducted a case study on the Shiyang River Basin, a typical mountain-oasis-desert inland river basin in northwestern China, using water balance and wavelet analysis methods. Long-term (1980–2020) monitoring data from river discharge and groundwater tables were used to construct the water balances and quantify the periodicity of the surface water and groundwater. We observed that over 2.90 billion m3 of transferred water during 2003–2020 mitigated the declining trend in groundwater, resulting in a change in water storage trend from –91.9 mm/y to –53.7 mm/y. IBTs contributed approximately 230 % of the increase in observed river runoff, 21 %–60 % (42 % on average) of the increase in total water storage, and 1 %–32 % (12 % on average) of the evapotranspiration deficit (i.e., the portion of actual evapotranspiration beyond climate-driven evapotranspiration). IBTs also significantly altered the seasonal fluctuation and periodicity of river flows and groundwater. Increased water availability promoted vegetation recovery and resulted in multiscale resonance periodicities with vegetation, ranging from monthly to interannual scales. Our results indicate that IBTs markedly modified the water cycle, hydrological regimes, and ecosystem processes in the study basin. Thus, we call for long-term monitoring of the timing, frequency, and magnitude of ecohydrological modifications from IBTs to provide critical information for effective watershed management policies to achieve long-term sustainable development in water-stressed regions.

Modeling spatial groundwater level patterns of Bangladesh using physio-climatic variables and machine learning algorithms

Groundwater monitoring is essential for sustainable groundwater resource management in a country like Bangladesh, where this precious resource is gradually declining due to over-extraction. However, traditional methods of acquiring groundwater level (GWL) data over a large area are time-consuming and expensive. To address this, this study proposes an alternative approach using freely available daily groundwater storage (GWS) gridded data from the Global Land Data Assimilation System (GLDAS) and other data sources such as population, rainfall, temperature, irrigation, and elevation. By employing different regression and machine learning models like multiple linear regression (MLR), regression trees, support vector machines (SVM), Gaussian process regression (GPR), and artificial neural networks (ANN), the study aimed to model GWL data for Bangladesh at a spatial resolution of 0.25° × 0.25°. In-situ weekly GWL data collected from 844 locations across the country were used for model development. The results indicated that GWS data alone was insufficient to estimate the spatial variability and trend of groundwater in Bangladesh. However, the comparison of different models showed that the ANN model performed better, with an overall correlation coefficient (R) of 0.95 and mean squared error (MSE) of 0.64 m2 when estimating GWL using GWS and other data. The study also identified population and rainfall as the most influential factors in determining GWL. The developed ANN model can be utilized to estimate GWL at locations where observation data are unavailable, enabling the monitoring of GWL for sustainable groundwater management in Bangladesh.

The impact of agricultural practices on groundwater depletion: A spatiotemporal analysis of India

ABSTRACTIn recent decades, intensive agricultural activities have adversely impacted the groundwater resources. The post‐green revolution era in India witnessed excessive irrigation practices that negatively impacted sustainable groundwater utilization. This study aims to analyze trends and patterns of groundwater depletion and identify potential factors to determine groundwater depletion across Indian states for the period 2004–2020. In doing so, percentage of safe blocks in terms of groundwater status is used as proxy for groundwater depletion. Employing the Mann–Kendal Method and Sen's slope, the study examines groundwater trends, while spatial analysis is conducted using Moran's I technique. Furthermore, a Fixed Effect‐Generalized Least Square (FE‐GLS) regression approach is employed to identify factors that influence groundwater status. Findings reveal the spatial autocorrelation of groundwater extraction among Indian states, which reflected by a Moran's I value of 0.62. Additionally, this study found that region of northern and southern India exhibits increasing trend groundwater depletion as compared to other regions. Based on the results of FE‐GLS regression and regression with Driscroll–Kraay standard error, our study indicates that crop intensity, gross irrigated land, gross sown area, and the area sown with water‐intensive crops have a negative and significant impacts on the percentage of safe blocks in terms of groundwater availability. Conversely, we found that annual rainfall has a positive and significant relationship with the percentage of safe blocks. From a policy perspective, the study suggests regulating the cultivation of water‐intensive crops and advocates for integrated policies to ensure sustainable water resource and food security – a balance often termed the food‐water‐energy nexus.

Ammonium enrichment, nitrate attenuation and nitrous oxide production along groundwater flow paths: Carbon isotopic and DOM optical evidence

Dissolved organic matter (DOM) plays a crucial role in the biogeochemical processing of reactive nitrogen in groundwater systems. However, the impacts of DOM on release of geogenic ammonium and transport and transformation of reactive nitrogen including nitrate attenuation under dynamics in groundwater level characteristic for floodplain environments remain unclear. In this study, we have identified the influence of riparian water level fluctuations on changes in the redox conditions, groundwater geochemical composition including the DOM mobilization in the piedmont recharge and the discharge area along groundwater flow paths. We have also evaluated the pivotal roles of DOM degradation in transport and transformation of nitrogen species including geogenic ammonium enrichment, nitrate attenuation, and dissolved nitrous oxide (N2O) production combining the stable carbon isotopic signatures and the optical characteristics of DOM. Along groundwater flow paths, the seasonal amplitudes of surface water levels were higher in the piedmont recharge area than those in the plain discharge area, and four DOM fluorescent components were identified through the parallel factor analysis (PARAFAC), with two terrestrial humic-like components (C1 and C2) in the piedmont recharge area, and two microbial humic-like components (C3 and C4) in the plain transition-discharge area. A positive correlation between stable dissolved inorganic carbon isotopic signatures (δ13C-DIC) and ammonium-nitrogen concentrations indicated that microbial degradation processes of DOM concomitantly promote the release of geogenic ammonium into groundwater. Ammonium enrichment and nitrate attenuation trend in groundwater was noted as one moved from the recharge area to the discharge area. Evidently, a clear correlation emerged where elevated dissolved N2O concentrations were linked to diminished ammonium-nitrogen levels and elevated nitrate-nitrogen levels. Additionally, groundwater exhibited higher dissolved N2O levels in the piedmont recharge area compared to the plain discharge area. These findings revealed that the impacts of groundwater DOM degradation on nitrate attenuation and dissolved N2O production in similar geogenic ammonium-affected Quaternary alluvial aquifers along groundwater flow paths, and established the theoretical basis for ensuring the security of local groundwater supply.

Occurrence and Distribution of Fluoride in Groundwater and Drinking Water Vulnerability of a Tropical Dry Region of Andhra Pradesh, India

There has been a growing concern over the occurrence of fluoride (F−) in groundwater and the impact of F− exposure on human health issues over the past decades. So, this study conducted a regional–scale assessment of the occurrence and trend of groundwater F− distribution [2014–2018] integrated with locally field–based investigations on F− exposure to a few selected families (10 households and 35 respondents) and reason behind their consumption of F− containing water (n = 18). In the local study, water samples were collected from multiple sources around the selected households by dividing them into consumptive and non–consumptive use. Results revealed that across the state of Andhra Pradesh, the occurrence of F− is more than the permissible limit in groundwater, and it has been increasing over the years (2014–2018) (average SD is 0.55), and the local study showed that the groundwater had an average of 1.5 mg/L F−, while other sourced water had an average of <1 mg/L F−. Most interestingly, nine families are consuming non–F− containing water (<0.52 mg F−/day) which is commercially available, while only one family is consuming F− containing groundwater and being exposed to >3 mg F−/day. This disparity in fluoride exposure is dependent on economic stability and health exposure policies.

Concurrently assessing water supply and demand is critical for evaluating vulnerabilities to climate change

AbstractAligning water supply with demand is a challenge, particularly in areas with large seasonal variation in precipitation and those dominated by winter precipitation. Climate change is expected to exacerbate this challenge, increasing the need for long‐term planning. Long‐term projections of water supply and demand that can aid planning are mostly published as agency reports, which are directly relevant to decision‐making but less likely to inform future research. We present 20‐year water supply and demand projections for the Columbia River, produced in partnership with the Washington State Dept. of Ecology. This effort includes integrated modeling of future surface water supply and agricultural demand by 2040 and analyses of future groundwater trends, residential demand, instream flow deficits, and curtailment. We found that shifting timing in water supply could leave many eastern Washington watersheds unable to meet late‐season out‐of‐stream demands. Increasing agricultural or residential demands in watersheds could exacerbate these late‐season vulnerabilities, and curtailments could become more common for rivers with federal or state instream flow rules. Groundwater trends are mostly declining, leaving watersheds more vulnerable to surface water supply or demand changes. Both our modeling framework and agency partnership can serve as an example for other long‐term efforts that aim to provide insights for water management in a changing climate elsewhere around the world.

Spatiotemporal variation of water balance components in Mashhad catchment, Iran: Investigating the impact of changes in climatic data and land use

Abstract The research aims to investigate the spatiotemporal changes of water balance components and distinguish the relative impacts of climatic data and land-use on groundwater level in northeastern Iran. This investigation employs the WetSpass-M model to estimate water balance and the Mann-Kendall test alongside Sen's slope estimator to evaluate trend. The study also assesses mean annual water balance components, considering diverse combinations of land-use and soil. The findings offer a hydrological insight, revealing that 14% of precipitation results in runoff, 29% of that recharging the aquifer; the remaining portion is lost through evapotranspiration. The trends in precipitation and simulated water components are not significant but a significant downward trend in groundwater is observed beyond a specific point in time. Based on this outcome, as well as the analysis of land-use changes, it was speculated that human activities in this fast-developing region might be implicated in the decline in groundwater levels. Analysis of water balance components in various soil and land-use combinations indicates that evapotranspiration exhibits greater variability within the land-cover class, while recharge is more influenced by soil texture. These findings enhance our understanding for identifying potential sites for artificial recharge and determining sustainable groundwater withdrawals based on spatiotemporal recharge patterns.

Spatial and Temporal Patterns of Groundwater Levels: A Case Study of Alluvial Aquifers in the Murray–Darling Basin, Australia

Understanding the temporal patterns in groundwater levels and their spatial distributions is essential for quantifying the natural and anthropogenic impacts on groundwater resources for better management and planning decisions. The two most popular clustering analysis methods in the literature, hierarchical clustering analysis and self-organizing maps, were used in this study to investigate the temporal patterns of groundwater levels from a dataset with 910 observation bores in the largest river system in Australia. Results showed the following: (1) Six dominant cluster patterns were found that could explain the temporal groundwater trends in the Murray–Darling Basin. Interpretation of each of these patterns indicated how groundwater in each cluster behaved before, during, and after the Millennium Drought. (2) The two methods produced similar results, indicating the robustness of the six dominant patterns that were identified. (3) The Millennium Drought, from 1997 to 2009, had a clear impact on groundwater level temporal variability and trends. An example causal attribution analysis based on the clustering results (using a neural network model to represent groundwater level dynamics) is introduced and will be expanded in future work to identify drivers of temporal and spatial changes in groundwater level for each of the dominant patterns, leading to possibilities for better water resource understanding and management.

Groundwater Variability Along with The Varying Coastline of Thiruvanathapuram City

Shoreline change is a constantly evolving phenomenon that threatens people and their livelihoods around the globe. India observes this phenomenon strongly at different locations being a tropical peninsular country with 6635kms of coastline. This study tried to analyze the effect of shoreline change on surrounding ground water reserves along Thiruvanathapuram coast in Kerala district of India. Net changes in coastline positions are statistically calculated and observed using Linear Regression Rate (LRR). The shoreline change rate shows most of the region are undergoing erosion, only few accretions or land formation are observed which was mostly artificially formed due to harbor building. The highest erosion rate in terms of LRR was -7m/year and highest accretion was 28m/year. We compared the shoreline change with groundwater variability along the coast and also groundwater salinity using electrical conductivity as the factor. The study observed decreasing trend of groundwater along the eroding coastline. The study also predicted decadal shoreline change along the Thiruvanathapuram coast was predicted using Kalman filter model.

Groundwater trend analysis and regional groundwater drought assessment of a semi-arid region of Rajasthan, India

Groundwater trend analysis and regional groundwater drought assessment of a semi-arid region of Rajasthan, India