Water Table Decline Research Articles

Assessing the efficiency of smallholder sugarcane production: The case of Faisalabad, Pakistan

Declining water tables and shrinking irrigation supply are two major challenges for agricultural production that increase production costs of high delta crops in Pakistan. Crop producers may tackle these threats by optimizing the use of available resources. To devise policies for improved resource use and cost reduction, assessing current efficiency levels and their determinants can provide useful information. This research assessed the technical, allocative, and groundwater-irrigation efficiency of smallholder sugarcane farms in Faisalabad, Pakistan using primary data for 56 tubewell solo owners, 37 tubewell shareholders, and 47 water buyers and applying the data envelopment analysis technique. The factor affecting the allocative efficiency were explored using the tobit regression. We found that the groundwater-irrigation efficiency ranged from 92% for the solo owners, 92% for shareholders, and to 83% for water buyers. On average, technical efficiency at sugarcane farms was more than 90%. Solo owners, shareholders, and water buyers achieved only 40%, 28%, and 37% of allocative efficiency, respectively. By improving the allocative efficiency through optimal allocation of inputs, farms can considerably decrease their costs for a given output level. The allocative efficiency was negatively associated with farmers’ age, farm size, tubewell depth, discharge rate and salinity in groundwater. Our findings imply that sugarcane farms can substantially reduce their production costs by installing smaller tubewells that match their crop irrigation requirement and groundwater depth. Further, improving the allocative efficiency of relatively large sugarcane farms, monitoring and regulating groundwater extraction to prevent further increase in groundwater and irrigation and soil management practices to reduce salinity can improve the efficiency.

Sustainable Groundwater Management, Addressing Depletion Through Advanced Technology and Policy

Groundwater depletion poses a critical threat to global water security, agriculture, and ecosystems, with unsustainable extraction rates contributing to declining water tables, land subsidence, and environmental degradation. This article explores the integration of advanced technology and policy frameworks as a sustainable solution for managing groundwater resources. Technologies such as remote sensing, artificial intelligence (AI), machine learning, and smart irrigation systems are playing pivotal roles in monitoring and optimizing groundwater usage. Additionally, blockchain technology offers transparency in water rights management, ensuring accountability in resource allocation, technological advancements alone are insufficient to address the issue. Effective policy frameworks, including regulatory limits, groundwater pricing, and community-based management, are necessary to enforce responsible water extraction and promote equitable access. International cooperation is crucial, particularly in regions where transboundary aquifers exist. This paper advocates for a collaborative approach that combines cutting-edge technology with robust governance to ensure sustainable groundwater management. Data-driven decision-making, public education, and the integration of technology into governance structures are essential for long-term groundwater conservation. By aligning these strategies, societies can mitigate the negative impacts of groundwater depletion and protect this critical resource for future generations.

HYDROPONICS FARMING – AN IMPROVED TECHNIQUE FROM SOIL CROP PLANT TO SOILLESS CROP PLANT

Due to rapid urbanization and industrialization, our conventional agriculture is facing the major challenges like as decrease in per capita availability of cultivable land, Global climate change, Poor soil fertility status, Unpredictable climate conditions, Water source pollution, decline in water table, Hazardous infectious disease etc. are threatening the food Production under conventional farming. As per 2020 World Population Data Sheet, World population is projected to increase from 7.8 billion in 2020 to 9.9 billion by 2050 and for this population we will need to increase the production by 70% in order to meet the calorie need of 9.8 billion populations. Feeding to such huge population could be a challenging task. Horizontal expansion of cultivable land isn’t possible, and, in such case, the sole solution seems is Vertical expansion and it requires very innovative technique i.e., HYDROPHONICS FARMING

Evaluating nitrate transport and accumulation in the deep vadose zone of the intensive agricultural region, North China Plain

Evaluation of the nitrate transport process in the deep vadose zone (DVZ) is important for groundwater quality management, especially in intensive agricultural regions, such as the North China Plain (NCP). The NCP produces ~20% of the total food grain in China, owing to timely groundwater irrigation and excessive chemical N fertilizer applications, and faces severe groundwater environmental degradation. This study evaluated the potential impacts of intensive agriculture on groundwater quality by investigating nitrate accumulation and transport in the DVZ of wheat-maize double-cropping field based on sediment sampling (maximum depth of 45.2 m) over three sub-regions of the NCP. The results showed that legacy nitrate‑nitrogen (NO3−-N) accumulated in the DVZ ranged from 118.5 to 6302.8 kg N ha−1 across the NCP; it increased with depth at an average rate of ~157 kg ha−1 m−1. Nitrate transport and accumulation in the DVZ were spatially varied and mainly controlled by the DVZ sediment textures, in addition to water and nitrogen inputs from the ground surface. Coarse sediments retained lower soil water content, resulting in less nitrogen storage; however, they provided greater nitrate transport velocity. Higher transport velocities observed in the alluvial-proluvial fan allowed chemical N fertilizer to reach the water table. However, in other regions, nitrate transport velocities were lower than the water table decline rates, implying that groundwater quality may not have been impaired by chemical N fertilizer. Furthermore, a reductive environment was identified in some areas with fine sediments, indicating a favorable environment for denitrification in the DVZ. The findings of the current study could provide an important foundation for groundwater quality management in agricultural areas, such as the NCP and similar regions.

A copula incorporated cellular automata module for modeling the spatial distribution of oasis recovered by ecological water diversion: An application to the Qingtu Oasis in Shiyang River basin, China

Assessing the impact of ecological water diversion on oasis restoration is critical for water resources and environmental management in arid inland basins. This study proposed a copula incorporated cellular automata (CA) module for modeling the oasis’s spatial distribution driven by ecological water diversion. Given the effects of groundwater depth and community expansion on oasis evolution, a water availability index and a neighbor vegetation index were proposed. These two indices were joint using the Clayton copula function, producing a vegetation suitability index that quantified vegetation growth’s habitat quality and provided the CA module’s basis to identify cellular categories. The CA module was integrated into a previously developed conceptual lumped ecohydrological model (CLEM), resulting in an improved CA-CLEM that outputted groundwater depth, oasis area, oasis NDVI, and oasis distribution data. The CLEM provided the oasis area changes for the CA module, which specified the spatial distribution of these changes. The CA-CLEM had a simple structure, low computation cost, and good performance, indicated by the application in the Shiyang River basin in Northwest China. Results show that an ecological water diversion of 30 million m3, with an average groundwater depth of 2.95 m, an oasis area of 25 km2, and an oasis NDVI of 0.36, would successfully recover the terminal Qingtu Oasis in 2020. The oasis distribution and its dynamic evolution processes were irregular because of the spatial heterogeneity of vegetation habitat suitability. The present Qingtu Oasis was fragile, and its sustainability relied on ecological water diversion. The reduction in water diversion would cause water table decline, oasis area shrinkage, vegetation degradation, and oasis fragmentation. The CA-CLEM combined with scenario analysis provides practical and reliable implications for managers and policymakers to improve ecological water diversion strategies.

Runoff, erosion, and nutrient transport arising from furrow irrigation in a corn conservation production system

AbstractContemporary row‐crop practices in the mid‐southern United States contribute to declining water tables and impairment of downstream waters, threatening the sustainability of irrigated agriculture and vital ecosystem services. This research was conducted to determine whether agro‐hydrology can be altered by cover crop or traffic pattern. The effects of cover crop {Austrian winter pea [Pisum sativum var. arvense (L.) Poiret], crimson clover [Trifolium incarnatum L.], cereal rye [Secale cereal L.], and tillage radish [Raphanus sativus L.]} and traffic pattern (traffic, nontraffic) on runoff, erosion, and nutrient transport from a furrow irrigation event were investigated at Stoneville, MS on a Commerce very fine sandy loam (a fine‐silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquept). Relative to winter fallow, the inclusion of a cover crop reduced erosion by at least 16% but had no effect on runoff or the transport of total P, total Kjeldahl nitrogen (TKN), soluble reactive phosphate (SRP), NH4–N, or NO3–N. Eliminating traffic in furrows reduced runoff, erosion, and SRP transport up to 13%. Traffic pattern had no effect on the transport of total P, TKN, NH4–N, or NO3–N. Regardless of treatment, total N loss never exceeded 0.2% of N applied as inorganic fertilizer. This research demonstrates that cover crop and equipment traffic pattern can be manipulated in reduced tillage systems to improve the sustainability of irrigated agriculture and ecosystem services in the mid‐southern United States.

Water table decline alters arthropod community structure by shifting plant communities and leaf nutrients in a Tibetan peatland

Water table decline is one of the most serious environmental problems in the peatland in the Qinghai-Tibetan Plateau. However, the effect of water table decline on the structure of aboveground arthropod communities is still not clear. We investigated changes in the abundance of different arthropod groups, and estimated the abundance, height, and biomass of the plant community in a soil water table reduction experiment to reveal the effect of water table decline on the arthropod community structure. The effect of water level decline on herbivorous arthropods varied according to the feeding habits. Specifically, water table decline treatment decreased the abundance of grass-preferring herbivores but increased the abundance of forb-preferring herbivores. However, the density of predators (e.g., spiders) did not change significantly. The variations in arthropod communities were correlated with the increase in forbs and leaf nitrogen content in the water table decline treatments. Our experiment demonstrated that the effect of water table decline on plant communities cascades upwardly to alter the arthropod community. Such trophic interactions should be considered in studies aimed at predicting shifts in the arthropods communities in a changing climate.

Groundwater Depletion in an Urban Environment under Semiarid Climate and Persistent Drought–City of Marrakesh (Morocco)

The quantitative monitoring of the shallow aquifer in Marrakesh and its surrounding area shows that the water table has been lowered gradually over the last 40 years, and attaining an acute decline in the early 2000s. This declining trend—if confirmed in the future—may lead to a water shortage, or even to a total aquifer depletion, which would be devastating for a region where economic activity and drinking water supply rely partly on groundwater resources. Two factors account for this situation: the hot semi-arid climate characterized by high temperatures and low precipitation, causing an inadequate groundwater recharge (deficit between rainwater supply and the potential evapotranspiration), and the over-pumping of groundwater from wells for intensive agricultural uses and some leisure activities (golf courses, waterparks and pools, for example). The objective of this study is to assess the hydrodynamic behaviour of the shallow aquifer in this context of persistent drought and semi-arid climate under intense use conditions. Based on earlier research studies and hydrological data recently collected from the field, a spatiotemporal analysis using a geographic information system has been conducted, allowing researchers to monitor the evolution of groundwater resources under the impact of intense exploitation. This study shows a general decline of groundwater level in the city of Marrakesh between 1962–2019. However, by dividing this period into three periods (1962–1985, 1986–2001 and 2002–2019), it is obvious that the main groundwater fall occurred during the two last decades, a period marked by highest recorded temperatures and decreased precipitation levels. This water table decline impacted 85% of the study area and is estimated at 0.9 m/year. The area most affected by the drawdown of the water table experienced a decline reaching 37 m between 2002 and 2019 (more than 2 m a year).

Groundwater resource protection and spring restoration in Upper Jhelum Basin (UJB), western Himalayas

Groundwater is a significant source of fresh and clean water to millions of people living in the Upper Jhelum Basin (UJB) of Kashmir, India. During the past two to three decades the decline of water table in the shallow aquifers led to a reduction of spring discharge and/or drying up of some springs and wells. In the present study, hydrogeological investigation was carried out to understand the causes and factors for drying up or attenuation of springs in alluvial aquifer(s) of the UJB. Exhaustive field campaigns were conducted in 2017 to collect field data and water samples were collected from tubewells, springs and streams for stable water isotopic analysis. The rampant excavation of riverbed minerals (sand and boulders) using high-tech machinery has intercepted the alluvial aquifers, which exacerbated the problem of water-table decline. The similar stable water isotopic composition of groundwater and stream water samples at certain locations indicates a good hydraulic connection exists between groundwater and stream water. The stable water isotopic composition also suggests that streams act as point sources of recharge at many locations. The results indicate that besides climate change, the shrinking of recharge areas (by constructing roads along stream banks, converting small ponds into cropland, etc.) and unplanned pumping are the dominant factors responsible for the drying up of the springs and wells in alluvial aquifers. The findings suggest that the aquifers and the springs can be restored by artificial recharge and by plugging the intercepted aquifers along river beds by construction of masonry check dams across the streams near the affected sites. These findings can help in restoration of groundwater level and lost springs across the Himalayas at local and regional scales.

Drainage increases species richness and density of soil macro-invertebrates in the Zoige peatland of eastern Tibetan Plateau

Soil macro-invertebrates play an important role in the decomposition process of soil organic matter. As the world’s largest alpine peatland, the Zoige peatland on the eastern Tibetan Plateau is experiencing the decline in water table level primarily because of historic drainage. However, little is known about the responses of soil macro-invertebrate communities to water table decline. To address this issue, we established a field drainage experimental platform in 2013, which consists of low (50 cm deep drainage ditch) and intermediate (20 cm deep drainage ditch) water table level treatments, and the ambient (no drainage ditch) plots. In July (warm season) and November (cold season) of 2019, we examined the species composition, richness, densities and the vertical distribution of soil macro-invertebrates. Results showed that the species composition differed significantly among treatments. Species richness and densities of overall and different trophic groups (i.e., detritivores, herbivores and predators) of soil macro-invertebrates were significantly higher in the drained treatments compared to the ambient plots. Moreover, soil macro-invertebrates moved down to deeper soil layers in the low water table treatments compared to the ambient plots. In addition, sampling season (warm vs. cold) did not affect the responses of soil macro-invertebrates to water table decline. These results indicate that soil macro-invertebrate community is sensitive to water table decline in the Zoige peatland. Given the recognized importance of soil fauna to ecosystem functioning, more attention should be paid to the conservation of peatlands.

MAR site suitability mapping for arid–semiarid regions by remote data and combined approach: A case study from Balochistan, Pakistan

Climate change, along with the rapid increase in population and mismanagement of water resources, resulted in a decline in the quality and quantity of groundwater worldwide. Balochistan, the largest and driest province of Pakistan, is located in the south western part of the country. This region is suffering from the declining water table, land subsidence, and intense soil erosion. Rapidly increasing population, sea level rise, increasing temperature, declining average annual precipitation, and short-duration intense rainfalls with reduced percolation rates are further aggravating the situation. Managed Aquifer Recharge (MAR) is considered as a solution to reduce the stress on groundwater resources and achieve resilience to climate change. Creating a MAR suitability map may be one of the steps to be taken to reach sustainable groundwater management. This study produced the first MAR suitability map of the Quetta Valley, the most densely populated city of Balochistan, and Poralai and Hingol coastal basins suffering from seawater intrusion. To construct the MAR suitability map, the online INOWAS platform was first used to narrow down the suitable MAR options. Then, the six influencing factors including geology, slope, land-cover, precipitation, drainage density, and soil were identified, and the raster map of each factor was scored and weighted using GIS tools and the Multi Influencing Factor (MIF) method. All the factors were integrated according to their weight by using the ‘Weighted Overlay Analysis’ tool and the Multi-Criteria Decision Analysis (GIS-MCDA) in ArcGIS to produce the final MAR suitability map. The suitability map divided the study area into high, moderate, low, and very low suitability classes. The results depict that 80% of Poralai Basin, 10% of Hingol Basin and less than 5% of Quetta Valley falls in the high MAR suitability zone especially for trenches, ditches, furrows, and leaky dams. The first MAR suitability map for the basins of Balochistan can serve as the guidance and screening tool to focus site specific studies for highly suitable areas for MAR implementation. In the following phase of the study, an analysis of source, quality, and final use of water can serve to design and develop the specific MAR structures according to local conditions and needs. The displayed method is applicable to further MAR suitability studies for other arid-semiarid regions.

Identifying the full spectrum of climatic signals controlling a tree species' growth and adaptation to climate change

Identifying the key climatic parameters controlling a tree species’ growth in a given environment can improve our understanding of the species’ adaptability to climate change. However, this can be significantly affected by the detection and analytical methodologies used, at least for water-limited ecosystems. To address this issue, we tested together for the first time the five key methods widely applied for detecting climatic drivers of tree growth. The test was applied on the growth dynamics of Pinus pinea L. (the last ca. 130 years) and for evaluating its climatic sensitivity (the last ca. 60 years), under contrasting climatic conditions, from sites in Italy and Greece. As predictors, we selected a high number of seasonal, annual, and multi-annual climate integration periods (626 variables in total for precipitation and SPEI) through running correlation analysis. Methods that retain low-frequency variability and persistence of past climatic signals in radial growth (ABD, RCS, and raw BAI) revealed that long-term precipitation accumulated over 3–6 years was the key driver for P. pinea growth in the wettest sites. These signals probably appeared because of the cumulative effects of past years’ rainfall in determining water table levels. They would have been missed if low-frequency climate and growth variability were not considered, how it happens using standardized BAI and TRW. In the driest site, productivity was low and explained by 1–2 years precipitation signals, suggesting that mostly moisture stored in topsoil from more recent rainfall sustained P. pinea growth, a typical shallow-rooted species. Thus, the loss in root contact with the declining water table may explain the higher vulnerability to drought stress at its dry-end distribution range, particularly under low precipitation. A further drop in water table levels, driven by global warming, will most likely increase such vulnerability. Hence, conservation efforts will require maintaining a stable water table, prohibiting groundwater overexploitation at P. pinea habitats. Reducing competition from other deeper rooted tree species, better adapted to drought and fire, may further benefit the species’ conservation status.

A two-layer numerical model of soil moisture dynamics: Model development

Simulating water moisture flow in variably saturated soils with a relatively shallow water table is challenging due to the high nonlinear behavior of Richards' equation (RE). A two-layer approximation of RE was derived in this paper, which describes vertically-averaged soil moisture content and flow dynamics in the root zone and the unsaturated soil below. To this end, the partial differential equation (PDE) describing RE was converted into two-coupled ordinary differential equations (ODEs) describing dynamic vertically-averaged soil moisture variations in the two soil zones subject to a deep or shallow water table in addition to variable soil moisture flux and pressure conditions at the surface. The coupled ODEs were solved numerically using the iterative Huen's method for a variety of flux and pressure-controlled top and bottom boundary conditions (BCs). The numerical model was evaluated for three typical soil textures with free-drainage and mixed flux-pressure head at the bottom boundary under various atmospheric conditions. The results of soil water contents and fluxes were validated using HYDRUS-1D as a benchmark. Simulated values showed that the new model is numerically stable and generally accurate in simulating vertically-averaged soil moisture in the two layers under various flux and prescribed pressure BCs. A hypothetical simulation scenario involving desaturation of initially saturated soil profile caused by exponentially declining water table demonstrated the robustness of the numerical model in tracking vertically-averaged moisture contents in the roots layer and the lower vadose soil as the water table continued to fall. The two-layer model can be used by researchers to simulate variably saturated soils in wetlands and by water resources planners for efficient coupling of land-surface systems to groundwater and management of conjunctive use of surface and groundwater.

Interaction of soil water and groundwater during the freezing–thawing cycle: field observations and numerical modeling

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

Local and non-local controls on seasonal variations in water availability and use by riparian trees along a hydroclimatic gradient

As global climate change continues to impact regional water cycles, we may expect further shifts in water availability to forests that create challenges for certain species and biomes. Lowland deciduous riparian forests are particularly vulnerable because tree species cannot migrate out of the stream corridor, and they rely on root zone water availability that is controlled by variations in both local climate conditions (e.g. precipitation, evaporation, and infiltration) and non-local hydroclimatic forcing (e.g. streamflow, snowmelt, recharge). To determine how the seasonal water source usage of riparian trees is controlled by local versus non-local variability in hydroclimatic regime, we reconstructed the seasonal oxygen isotope (δ 18 O) signature of water used by two riparian tree species with contrasting rooting depths, comprising ∼800 δ 18 O tree-ring cellulose measurements from 12 tree-level decadal time-series at sub-annual resolution (six samples per year), along a strong hydroclimatic gradient within the Rhône River basin, SE France. These results were evaluated alongside δ 18 O measurements made from potential endmember water sources and independent hydroclimatic metrics. Thus we characterize the seasonal evolution of both potential water availability at distinct rooting depths and tree water source use and investigate the generalized riparian tree response to seasonal variations in local versus non-local hydroclimatic forcing over a decade. We show: (a) distinct seasonal water use between species, based on differential access to groundwater; (b) substantial source switching in both species based on evolving water availability; and (c) that riparian trees are more dependent on locally controlled soil moisture with distance downstream, creating increased vulnerability to locally increasing temperatures. We also find that deeply rooted trees in lowland riparian floodplains are potentially vulnerable to climate change because of their high dependence on water supply from mountains. This effect is more pronounced downstream, where seasonal water table decline may lead to loss of water required for deeply rooted trees.

Responses of leaf carbon, nitrogen, and phosphorus stoichiometry of Carex muliensis to water table drawdown in an alpine marsh on the Ruoergai Plateau, China.

Based on a field water table drawdown manipulation platform of Naleqiao marsh on the Rueorgai Plateau, we lifted in situ soil block of 1 m×1 m by 20 cm for simulating water table decline, and analyzed the response of carbon, nitrogen, and phosphorus stoichiometry in the wetland species Carex muliensis from June to September 2020. The results showed that there was no significant difference in leaf C content during the whole growing season, while N and P content gra-dually decreased along the growing season. After the drawdown of water table, the C content in leaves during the growing season was not consistent. Water table drawdown increased leaf C content in the early and middle growth stages, but changed little in the peak growth stage. Water table drawdown significantly increased leaf N content, while significantly decreased leaf P content. C:N, C:P, and N:P for leaves all increased along the whole growing period. The relative growth rate of C. muliensis was positively correlated with leaf C:N, but negatively correlated with leaf C:P and N:P. Water table drawdown significantly decreased leaf C:N, while significantly increased leaf C:P and N:P, which significantly reduced the relative growth rate of C. muliensis. The decrease of foliar P content induced by water table drawdown was the main regulating factor for the decrease of single leaf weight and specific leaf weight.

Elevated salinity and water table drawdown significantly affect greenhouse gas emissions in soils from contrasting land-use practices in the prairie pothole region

Land-use practices can alter shallow groundwater and salinity, further impacting greenhouse gas (GHG) emissions, particularly in the hydrologically dynamic riparian zones of wetlands. Emissions of CO2, CH4, and N2O were estimated in soil cores collected from two prairie pothole region (PPR) sites with three adjacent land-use practices (i.e., annual crop = AC, pasture = PA, and short rotation willow = SRW) and treated with declining water table depths (2 to 26 cm), and salinity (S0 = control, S1 = 6 mS cm−1, and S2 = 12 mS cm−1) in a microcosm experiment. Land-use practices significantly (p < 0.001) affected GHG emissions in soils from both sites in the order of PA > AC = SRW. Compared to the control, emissions of CO2 and CH4 were significantly lower under higher salinity treatments (i.e., S1 and S2), while N2O was significantly higher (p < 0.05). Emissions under declining groundwater table depths were significantly (p < 0.001) variable and specific to each gas, indicating the impacts of shifted soil moisture regime. Overall, the CO2 and CH4 emissions increased up to week four and then decreased with declining water table depths, whereas N2O emission increased up to a maximum at week six. The soils from SRW had considerably lower global warming potential compared to AC and PA. Groundwater salinity in soils from contrasting land-use in the PPR has significant impacts on GHG emissions with potential for crucial climate feedback; however, the magnitude and direction of the impacts depend on hydrology.

Plan B water assessment: Efficiency and circularity for agricultural and municipal adaptation to water scarcity

Municipal supply of water under climate variations, growing population, uncertainty, and scarcity, requires water planners to devise feasible and sustainable water sourcing plans; especially for territories relying on groundwater. The conventional ways to cope with water scarcity will no longer guarantee reaping the maximum benefits of declining available water resources. Efficiency and circularity of water are claimed as essential criteria for seeking solutions in designing long-term supply management. A Plan B water assessment applied to a group of municipalities in dry areas of Colombia, is proposed as a hydro-economic model aimed at providing inputs for water resources planning, in which the depletable and common-pool character of aquifers are incorporated. A declination speed index is introduced in two ways: the surface → water table distance and water table → saturated thickness distance. This issue should not be overlooked if spatial differentiation in water tables is incorporated in groundwater extraction permits analysis for multiple and convergent water users. Research results are promising for sustainability of water management in dry areas around the world. Respect to status quo situation a 22% of efficiency gain might be achieved in the next 20 years in Sucre – Colombia, under an efficient model of water consumption. If an efficient and circular water management model is endeavored, multiple gains would be harvested for the benefit of water users and ecosystems relying on aquifers. Increased efficiency is mostly driven by 30 million m3 sewage water recirculated in agriculture, which in turn would prevent aquifer extraction for this activity. In business-as-usual scheme, water efficiency gap will be wider; extraction costs will rise to prohibitive levels for low income municipalities; the declining water tables will oblige to make new punches by simultaneous water users and water declination index calculated would reflect a precipitous decay. Research results provide empirical evidence to the discussion on possible solutions for sustainable and efficient water management as stated in Sustainable Development Goals; specifically target goal 6.4 determines that water efficiency and sustainability in water withdrawals should be accomplished. Local setting on water resources availability, competition on resources, types of users, sewage water treatment technology, energy costs, and institutions in time and place, would determine the replicability of research results.

Long-term sustainability of groundwater resources in the central Ganga Alluvial Plain, India: Study from Gomti River Basin

Groundwater is the major primary source of drinking and irrigation water for nearly 500 million inhabitants in both rural and urban areas of the Ganga Alluvial Plain (GAP) in India. Indiscriminate pumping of groundwater primarily from the shallow parts of the alluvial aquifer system is leading to rapid decline in water tables. It is expected that in coming years, the stress on groundwater will only increase due to steadily rising urbanization and additional demands for water and land, as well as by impending weather anomalies and shifts in availability of water during seasons when demands for irrigation and ecological needs are high. In the present study, Inverse Distance Weighted (IDW) interpolation method is used using pre- and post-monsoon groundwater levels from 764 observatory wells and peizometers to assess the trends of declining groundwater in the Gomti River Basin (GRB) during 2005 to 2015. Groundwater potential zone maps were composed using water depths data and Cartosat-1 satellite images delineating the area under rising and falling groundwater tables. The loss of shallow groundwater was clearly visible during the 2005–2015 periods. The decline is attributed to intensive irrigation from groundwater as well as peri-urban growth around the state capital. This study can apprise the planners and local administrators of the effects of irrigation and urbanization on the groundwater regime in the fast growing regions of the basin.

Groundwater contamination and health risk posed by industrial effluent in NCR region

More than 90% of the urban water supplies in the Yamuna Flood Plain come from the groundwater. Moreover, the irrigation during non-monsoon months is totally dependent on the groundwater. The upcoming townships in the Yamuna Flood Plains add to the extra taxation on the groundwater resources of the region. As a result of the additional demands generated due to increasing population both in numbers and density, the underground water resources are depleting at a faster rate as the water table has been showing a declining trend over the years. As a result of this declining water table, not only the fresh water potential is decreasing but also the eco-system, especially the vegetation cover has been affected and requires a lot of maintenance. Threat to groundwater is also imposed by overexploitation and contamination of groundwater. The percolation of contaminants from these units pose a greater risk to ground water contamination and in turn affect human health. During course of the research, we have not come across any study which has solely focused on contamination due to heavy metals found in effluent discharged from these industrial units, so this study has solely focused on heavy metal contamination and its effects in major Industrial areas of NCR Delhi.There has been a rapid decline in ground water table in and around Delhi owing to rapid urbanization and increase in population over the decades gone by, Therefore, there is an immediate need to arrest this decline to avoid desertification of Delhi in near future. Therefore, the study will also go into the details of water table decline and its rate of progression et.to know the present trend and future Scenario.