Net Groundwater Research Articles

Comparison of groundwater distribution, exchange and storage between cropland and forestland over the past 115 years

ABSTRACT Using the US Geological Survey groundwater model, we compared spatial distribution, flow exchange, and storage of groundwater between cropland and forestland in the Upper Yazoo River Watershed, Mississippi, from 1900 to 2014. Under normal climate, average groundwater head declined 2.7 m in cropland but only 1 m in forestland over the 115 years. The average groundwater flow from forestland to cropland surpassed the reverse flow by a factor of 238, owing to a higher elevation in forestland and intensive groundwater pumping in cropland. Cropland was a net groundwater sink while forestland was a net groundwater source under all climates. Our findings underscore the discernible impacts of climate changes on groundwater storage and suggest that afforestation in the region would be an alternative for saving groundwater resources and supplying more waters to croplands. This study offers valuable insights into groundwater supply planning not only in Mississippi but also in comparable situations worldwide.

Aquifer vulnerability valorization via DRASTIC index-based assessment within litho-facies of a coastal environment

Determining the degree of an aquifer’s susceptibility to pollutants is an important tool for policy planning in subterranean water administration and conservation. In this work, subterranean water vulnerability was appraised with the use of DRASTIC methodology, which employs seven parameters: depth to groundwater (D); net groundwater recharge (R); aquifer media (A); soil media (S); topography (T); influence of vadose zone (I); and hydraulic conductivity (C). Different ratings were given to each parameter based on the hydro-geological and geo-electrical information obtained from the study area. Geo-electrostratigraphic data was acquired with vertical electrical soundings and electrical resistivity tomography surveys. The results demonstrated the existence of geoelectrical layers with variable resistivities ranging from high to low, with variable curve types. Longitudinal conductance measures indicated moderate subterranean water protective capacity. Analysis of DRASTIC vulnerability indices showed that the aquifer indicated moderate to high vulnerability to contamination. Vulnerability maps were generated to indicate locations of high vulnerability, the goal being to prevent indiscriminate haphazard and wildcat abstraction of groundwater in such locations. The quality category index (QCI) generated for the DRASTIC model indicated that underground water susceptivity is dependent on all 7 parameters employed in the model, with the most critical determinants being the depth to aquifer (D), net recharge (R), aquifer media (A), and impact of the vadose zone (I). The work recommends that anthropogenic activities that could contaminate groundwater resource be halted as the resource is indicated by DRASTIC models as being vulnerable.

Effects of climate variability and change on groundwater impacts of forestry plantations

AbstractQuantifying water use of various water consumers is an essential part of sustainable water management. Annual evapotranspiration (ET) of plantation forests often exceeds that of dryland agriculture, which in South Africa and South Australia has resulted in restrictions on plantation development. In the latter case, water licences are issued to commercial forestry plantations to account for higher ET compared to dryland pasture. Unlike irrigated crops, it is not practicable to measure water use of plantations directly and so in South Australia a set of ‘deemed’ average water use rates has been applied since 2013, based on species and depth to groundwater. Since South Australia's ‘deemed’ rates were calculated, additional plot‐scale measurements of annual ET from plantations <2 years old and post‐canopy closure have been used to quantify various components of ET. This has enabled development of two empirical ET models for plantations in South Australia's Lower Limestone Coast, and facilitated an advanced understanding of the effect of plantations on hydrological processes, particularly in relation to groundwater use. In this study, we applied these models to estimate rotation‐averaged annual ET and net groundwater impacts (net groundwater extraction plus recharge reduction compared to pasture) of plantations, driven by climate and groundwater depth, for comparison with the deemed rates. The modelling suggests that the groundwater impacts of plantations vary in space and time and that the deemed rates over‐estimate these impacts, on average. Accounting for variation in the effects of climate on the various components of ET, both spatially and temporally, may allow for more flexible rules for water resource allocation than using any simple, rule‐of‐thumb approach.

Use of remote sensing, spatial and geophysical modeling, and real recharging capabilities to identify suitable areas for groundwater exploitation in dry coastal areas

Accurate identification of groundwater potential areas in arid regions is an important task for groundwater management and sustainability. As a result, this study used the innovative integration of remote sensing (RS), geographic information system (GIS), watershed modeling system (WMS), geophysical survey, and water mass balance equation to identify potential groundwater areas in the W. Dara, Eastern Desert, Egypt. A weighted spatial probability model (WSPM) of groundwater potential based on eight regulatory factors was implemented within ArcGIS software. Drainage density (DD), precipitation (P), net groundwater recharge (NGR), terrain slope (TS), lineament density (LD), lithologic group (LG), water quality (TDS), and depth to groundwater level (DGW) are the aspects considered. The Analytical hierarchy process (AHP) method was used to assign weights to these parameters, and their accuracy was estimated using the consistency ratio (CR). The resulting groundwater potential map classified W. Dara study area into five categories, ranging from very low to very high potential. A geophysical survey, in the form of Vertical Electrical Sounding (VES) and Transient Electromagnetic (TEM), was conducted along W. Dara to validate the results of the WSPM, which identified areas of high groundwater potential. The 1D inversion of VES/TEM shows that the central and western parts of W. Dara are considered the most promising areas for groundwater occurrence, and are located in areas of high and very high potential classes derived from WSPM. Moreover, the results of VES and TEM surveys showed that the proposed aquifers (Nubian Sandstone, Miocene, and Quaternary) in the study area are horizontally and vertically connected through a set of normal faults traversing NW-SE. Ten sites have been proposed for drilling additional exploitative wells in W. Dara area based on the WSPM and geophysical survey with the aim of sustainable development. Thus, the integrated techniques applied in this study proved effective in accurately determining the development strategy for arid and semi-arid coastal areas, especially those that suffer from scarcity of rainfall and increased agricultural reclamation requirements in remote areas.

The lake and groundwater interaction based on water balance in Dongting Lake, China

Study region: Dongting Lake (DTL), the second largest freshwater lake in China, plays a crucial role in regulating and storing water within the Yangtze River Basin.Study focus: The study utilized the water balance method to extensively investigate the exchange volume of groundwater and DTL from 2003 to 2020. Furthermore, we analyzed the impact of climate change and human activities on the interaction between groundwater and DTL.New hydrological insights for the region: Unlike previous studies, our study further included the ungauged runoff, providing a more comprehensive assessment of the water balance of DTL. From May to July, groundwater recharge from DTL, with an average monthly recharge of 0.71 km³. Conversely, groundwater discharges into DTL from August to April of the following year, with an average monthly discharge of 1.12 km³. The net groundwater discharge into the lake from 2003 to 2020 amounts to 7.98 km³/yr. Intriguingly, precipitation over the lake contributes a mere 0.6% to the total inflow, while lake evapotranspiration constitutes only 0.4% of the total outflow. Inflow runoff and outflow runoff play a leading role in the water balance of DTL, significantly influencing the exchange capacity between the lake and groundwater. Groundwater discharge into the lake serves as compensation for diminished runoff stemming from extreme climate occurrences, like droughts, and anthropogenic actions such as dam construction.

Multivariate Assessment of Groundwater Depletion and Recharge Prospect in a Sub-tropical Basin of Eastern India

Abstract The present study aims to highlight the groundwater-stress condition of the Quaternary 一 recent alluvial region escalated by anthropogenic extraction of water resources in the western Bengal Basin (Purba Bardhaman, West Bengal, India). With the rapid development of irrigation technology, high crop yield, water- consumed rice varieties, and high cropping intensity, the farmers of the river basin go to deeper underground aquifers (>180 m bgl) to extract water for summer rice (Boro) cultivation. In this study, the five semi-critical blocks (Mangolkote, Bhatai; Manteswai; Purbasthali II, and Memari II) of Purba Bardhaman district have experienced statistically significant pre-monsoon fall (0.404 m yr- 1 to 1.099 m yr-1) and post-monsoon fall of groundwater level from 0.486 m yr-1 to 2.214 m yr-1. Principal component analysis reflects that annual irrigation draft, annual replenishable groundwater unit, net groundwater availability, Boro rice cultivation area, area to be covered on each day irrigation for Boro, and daily pump discharge required for Boro irrigation are the key factors to escalate groundwater decline. This study reveals that Galsi II, Bardhaman I and II, Katwa I, and Purbasthali I blocks will experience a water-stress or groundwater drought in future. The model of groundwater recharge potential zone shows four principal categories of groundwater prospect area in the basin, viz., poor (0.08 %), moderate (5.78 %), good (68.96 %), and very good (25.18 %). These findings provide the relevant information for planners of groundwater resources to upscale groundwater management procedures and enhance the sustainability of agricultural systems in the study area.

Warming temperatures exacerbate groundwater depletion rates in India.

Climate change will likely increase crop water demand, and farmers may adapt by applying more irrigation. Understanding the extent to which this is occurring is of particular importance in India, a global groundwater depletion hotspot, where increased withdrawals may further jeopardize groundwater resources. Using historical data on groundwater levels, climate, and crop water stress, we find that farmers have adapted to warming temperatures by intensifying groundwater withdrawals, substantially accelerating groundwater depletion rates in India. When considering increased withdrawals due to warming, we project that the rates of net groundwater loss for 2041-2080 could be three times current depletion rates, even after considering projected increases in precipitation and possible decreases in irrigation use as groundwater tables fall. These results reveal a previously unquantified cost of adapting to warming temperatures that will likely further threaten India's food and water security over the coming decades.

Climate-warming-driven changes in the cryosphere and their impact on groundwater–surface-water interactions in the Heihe River basin

Abstract. The Heihe River basin in northwest China depends heavily on both anthropogenic and natural storage (e.g., surface reservoirs, rivers and groundwater) to support economic and environmental functions. The Qilian Mountain cryosphere in the upper basin is integral to recharging these storage supplies. It is well established that climate warming is driving major shifts in high-elevation water storage through loss of glaciers and permafrost. However, the impacts on groundwater–surface-water interactions and water supply in corresponding lower reaches are less clear. We built an integrated hydrologic model of the middle basin, where most water usage occurs, in order to explore the hydrologic response to the changing cryosphere. We simulate the watershed response to loss of glaciers (glacier scenario), advanced permafrost degradation (permafrost scenario), both of these changes simultaneously (combined scenario) and projected temperature increases in the middle basin (warming scenario) by altering streamflow inputs to the model to represent cryosphere-melting processes, as well as by increasing the temperature of the climate forcing data. Net losses to groundwater storage in the glacier scenario and net gains in the permafrost and combined scenarios show the potential of groundwater exchanges to mediate streamflow shifts. The result of the combined scenario also shows that permafrost degradation has more of an impact on the system than glacial loss. Seasonal differences in groundwater–surface-water partitioning are also evident. The glacier scenario has the highest fraction of groundwater in terms of streamflow in early spring. The permafrost and combined scenarios meanwhile have the highest fraction of streamflow infiltration in late spring and summer. The warming scenario raises the temperature of the combined scenario by 2 ∘C. This results in net groundwater storage loss, a reversal from the combined scenario. Large seasonal changes in evapotranspiration and stream network connectivity relative to the combined scenario show the potential for warming to overpower changes resulting from streamflow. Our results demonstrate the importance of understanding the entire system of groundwater–surface-water exchanges to assess water resources under changing climatic conditions. Ultimately, this analysis can be used to examine the cascading impact of climate change in the cryosphere on the resilience of water resources in arid basins downstream of mountain ranges globally.

Water Cycles and Geothermal Processes in a Volcanic Crater Lake

Exploring how the hydrological and thermal conditions of a volcanic lake change in response to volcanic activity is important to identify the signs of a volcanic eruption. A water cycle system and a geothermal process in a crater lake, Okama, in the active Zao Volcano, Japan, were explored by estimating the hydrological and chemical budgets of the lake, and analyzing the time series of lake water temperature, respectively. In 2021, the lake level consistently increased by snowmelt plus rainfall in May–June, and then stayed nearly constant in the rainfall season of July–September. The hydrological budget estimated during the increasing lake level indicated that the net groundwater inflow is at any time positive. This suggests that the groundwater inflow to the lake is controlled by the water percolation into volcanic debris from the melting of snow that remained in the catchment. Solving the simultaneous equation from the hydrological and chemical budgets evaluated the groundwater inflow, Gin, at 0.012–0.040 m3/s, and the groundwater outflow, Gout, at 0.012–0.027 m3/s in May–September 2021. By adding the 2020 values of Gin and Gout evaluated at the relatively high lake level, it was found that Gin and Gout exhibit highly negative and positive correlations (R2 = 0.661 and 0.848; p < 0.01) with the lake level, respectively. In the completely ice-covered season of 15 December 2021–28 February 2022, the lake water temperature increased between the bottom and 15 m above the bottom at the deepest point, which reflects the geothermal heat input at the bottom. The heat storage change during the increasing water temperature was evaluated at a range of −0.4–5.5 W/m2 as the 10-day moving average heat flux. By accumulating the daily heat storage change for the calculated period, the water temperature averaged over the heated layer increased from 1.08 to 1.56 °C. The small temperature increase reflects a stagnant state of volcanic activity in the Zao Volcano. The present study could be useful to investigate how an active volcano responds to water percolation and geothermal heat.

A market-based mechanism for long-term groundwater management using remotely sensed data

Groundwater markets improve the agricultural economy by transferring water entitlements from low-efficient users to high-efficient ones to maximize productivity. Aiming at developing an efficient groundwater market, the environmental effects of the market mechanism should be assessed, and a reliable method for monitoring water consumption needs to be employed. Toward this end, this paper proposes three annual smart groundwater market mechanisms to maximize water net benefits, minimize groundwater withdrawal, and precisely measure water consumption in agricultural fields. To guarantee the aquifer's safe yield in each mechanism, a groundwater simulation model (i.e., Groundwater Modeling System (GMS)) is used to control groundwater table drawdown at the end of the planning horizon. In addition, the fields' evapotranspiration (ET) is estimated using Surface Energy Balance Algorithm for Land (SEBAL) and Mapping Evapo Transpiration at high Resolution with Internalized Calibration (METRIC) algorithm to measure the net groundwater consumption during the market. In this regard, we evaluated the algorithms' performances using observed data from a local lysimeter. They are applied to the Nough plain in Iran to assess the effectiveness of the proposed market framework. The findings illustrate their efficiency in recovering approximately 80% (23.33 million cubic meters (MCM)) of groundwater loss due to overexploitation in the study area and increasing the users' annual benefits by 10.6% compared to the non-market condition. In addition, results imply that the METRIC model approximates daily crop ET with a higher accuracy level than the SEBAL model with RMSE, MAE, and Percentage Error of 0.37 mm/day, 0.32 mm/day, and 14.92%, respectively. This research revealed that the proposed market framework is a powerful tool for reallocating water entitlements and increasing water productivity in arid and semi-arid regions.

Combined Analysis of Net Groundwater Recharge Using Water Budget and Climate Change Scenarios

Estimating the groundwater recharge rate is essential in all groundwater-related fields, including groundwater development, use, management, modeling, and contamination analysis. In this study, we proposed a combined method of water budget and climate change scenario for estimating the net groundwater recharge rate in the Nakdong River watershed (NRW), South Korea. For the climate change scenario method, the representative concentration pathway (RCP) 4.5 and 8.5 climate scenarios were adopted. First, using the water budget method from 2009 to 2018, the net groundwater recharge rate (NGRR) of 12.15–18.10% relative to annual precipitation (AP) was obtained, subtracting direct runoff (DR) of 21.18–25.32% relative to AP, evapotranspiration (EP) of 40.53–52.29% relative to AP, and baseflow of 12.42–17.84% relative to AP, from the AP (865–1494 mm). The average annual NGRR of the NRW was 200 mm (15.59%). Second, the mean NGRRs from 2009 to 2100 under the RCP 4.5 and RCP 8.5 scenarios were anticipated as 8.73% and 7.63%, respectively. The similarity between the water budget and climate change scenarios was confirmed using data from 2009 and 2018. According to the simple climate change scenario, it is predicted that annual precipitation will increase over the years while the groundwater level and net groundwater recharge rate will decrease. Nonetheless, the estimated NGRR by the water budget method in this study possesses uncertainty due to using potential ET instead of actual ET which should be estimated by considering soil water content.

Improved Darcian streambed measurements to quantify flux and mass discharge of volatile organic compounds from a contaminated aquifer to an urban stream

Quantifying VOC transport from contaminated groundwater to streams is challenging and important for understanding off-site migration of VOCs, cross-media contamination (groundwater to surface water and eventually air), and potential impacts on downstream ecosystems and human populations. A streambed point sampling approach was used to quantify fluxes of water and 14 VOCs from groundwater to an urban stream in North Carolina, USA, during summer (June 2015) and winter (January 2016). The approach is unique in coupling measurements of vertical hydraulic conductivity, vertical hydraulic head gradient, and groundwater VOC concentration at each individual sampling point, reducing or eliminating some potential concerns with other Darcian methods for quantifying VOC inputs to streams.Most results were consistent with discharge of two main VOC plumes on opposite sides of the stream. Plume 1 from the west side was dominated by cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC) at mean concentrations of 19 and 11 μg L−1, respectively. Plume 2 from the east side was dominated by benzene (mean concentration 56 μg L−1). Plume 2 was not previously known, and the improved sampling approach allowed VOC discharge from both plumes to be quantified simultaneously.For 13 of the 14 detected VOCs, the mean VOC flux from groundwater to the stream (fVOC) was higher in January 2016 than in June 2015, mainly because groundwater flux was higher in January. The only exception was cDCE, the most abundant VOC in Plume 1, which had mean fVOC values of 9.8 and 9.5 mg m−2 d−1 in June 2015 and January 2016, respectively. Benzene was the most abundant VOC in Plume 2 and had mean fVOC values of 11 and 37 mg m−2 d−1 in June 2015 and January 2016, respectively. High groundwater flux drove almost all the occurrences of high VOC flux. For a given VOC, the flow-weighted mean concentration (with each VOC concentration weighted by the upward groundwater flux at the VOC sampling point) was generally larger than the unweighted mean concentration. Thus, flow-weighting of concentrations gave a more accurate indication of the average VOC concentration in net groundwater discharge to the stream.An estimate of total VOC mass discharge from groundwater to the study reach of the stream, 3.6 kg of VOC per year, was based on the fVOC results and streambed area in the reach. The bulk of this discharge was due to benzene, cDCE, and VC, with individual mass discharges of 2.1, 0.83, and 0.40 kg yr−1, respectively. Estimates of maximum potential VOC degradation in the streambed suggest that the 3.6 kg yr−1 estimate of mass discharge was not sensitive to potential degradation of VOCs in the streambed sediments above the groundwater sampling depth.

Estimating the long-term deformation and permanent loss of aquifer in the southern Junggar Basin, China, using InSAR

Groundwater is the main water source for agricultural irrigation in arid/semi-arid agricultural region. Overexploitation of groundwater inevitably leads to permanent loss of aquifer and ground subsidence. The oasis agricultural area in the southern Junggar basin (JSOAA) is one of the largest oasis agricultural areas in western China. In this study, we, for the first time, recover the regional-scale ground displacements time-series of JSOAA, using all ALOS-1/PALSAR (2007–2010) and Sentinel-1 (2015–2020) data. The results show that there are multiple subsidence areas related to groundwater overexploitation. From 2007 to 2010, the area with a subsidence rate greater than 10 mm/yr is about 5876.2 km2, accounting for 13.2 % of the total area of JSOAA. From 2015 to 2020, these values are about 16146.7 km2 and 36.3 %. In the areas with concentrated groundwater exploitation, the small separate subsidence areas grew larger and became connected, and finally developed into giant subsidence clusters. The maximum cumulative deformation of JSOAA exceeded 400 mm from 2007 to 2010, and 500 mm from 2015 to 2020. We modeled the surface subsidence caused by the permanent aquifer loss, and estimated the volume strain of aquifer in JSOAA. The total volume strain of the aquifer is 2.73 km3 between 2007 and 2020. Moreover, we estimated the aquifer storage coefficient and the net groundwater deficit of JSOAA. The results of this study will serve for JSOAA aquifer health detection, ecological environment stability assessment, and sustainable development of the agricultural economy.

Assessment of groundwater at Kurukshetra district

Abstract Mankind depends on surface water and groundwater resources to meet basic requirements. Groundwater is a limited resource that can be replenished. Instead of surface water, groundwater can be an alternate supply to meet a region's water demand for household, agriculture, and industrial uses. As a result, a thorough assessment is required to ensure the resource's long-term viability. The main aim of the research is to identify potential zones using remote sensing and quantification of groundwater resources. In the present study, the potential zones were identified by using the weighted overlay technique in ArcGIS software by considering eight influencing factors, and the estimation of groundwater was carried out using GEC 2015 methodology. The study discovered that the study area has a good potentiality of groundwater in the southern region. Further estimates were made for the period April 2020–March 2021 by taking into account recharge by rainfall, irrigation return flow, seepage by canals, and draft by industries, domestic, irrigation, and evapotranspiration. The research reveals that the net groundwater recharge of 0.16284361 million ha-m was depleted in the study area. This analysis concludes that the groundwater in the study area is critical and becoming an overexploited zone.

Effects of a Volcanic-Fluid Cycle System on Water Chemistry of a Deep Caldera Lake: Lake Tazawa, Akita Prefecture, Japan

Lake Tazawa, the deepest lake (423.4 m depth at maximum) in Japan underwent drastically changed water quality in 1940, because volcanic water from two active volcanos was then drawn into the lake for power generation and irrigation. Thereby, the pH of lake water decreased from 6.7 to 4.2, which exterminated a land-locked type of sockeye salmon, Oncorhynchus nerkakawamurae (locally called Kunimasu trout). Additionally, the mean residence time of lake water changed from 195 years to 8.9 years by rapidly increasing the outflow for power generation and irrigation. In this study, long-term chemical fluxes controlling lake water chemistry were obtained, and a groundwater water cycle system between the lake and the volcano was explored by estimating hydrological and chemical budgets of the lake. In the chemical budget estimate, two ionic species, SO42− and Cl−, in volcanic fluids were chosen and each mass conservation equation was yielded. The hydrological budget estimate gave us the net groundwater inflow at −1.36 m3/s on average over three periods in 2020–2021, and then the simultaneous equation coupled with the chemical budget equation allowed us to separate into groundwater inflow and outflow at 6.01 m3/s and 7.37 m3/s, averaged over the three periods, respectively. The evaluated groundwater inflow and outflow were compared with those of the other crater or caldera lakes. The linear relationship between the lake volume and the magnitude of groundwater inflow or outflow suggests that the groundwater cycle scale in such a lake increases with the magnitude of the volcanic eruption to have formed the lake.

A century of groundwater accumulation in Pakistan and northwest India

The groundwater systems of northwest India and central Pakistan are among the most heavily exploited in the world. However, recent, and well-documented, groundwater depletion has not been historically contextualized. Here, using a long-term observation-well dataset, we present a regional analysis of post-monsoon groundwater levels from 1900 to 2010. We show that human activity in the early twentieth century increased groundwater availability before large-scale exploitation began in the late twentieth century. Net groundwater accumulation in the twentieth century, calculated in areas with sufficient data, was at least 420 km3 at ~3.6 cm yr–1. The development of the region’s vast irrigation canal network, which increased groundwater recharge, played a defining role in twentieth-century groundwater accumulation. Between 1970 and 2000, groundwater levels stabilized because of the contrasting effects of above-average rainfall and the onset of tubewell development for irrigation. Due to a combination of low rainfall and increased tubewell development, approximately 70 km3 of groundwater was lost at ~2.8 cm yr–1 in the first decade of the twenty-first century. Our results demonstrate how human and climatic drivers have combined to drive historical groundwater trends.

Numerical modeling for the temporal variations of the water interchange between groundwater and surface water in a regional great lake (Poyang Lake, China)

For areas possessing both regional-scale floodplain lakes and complex river system, the allocation pattern of water interchange between the groundwater and the lakes and rivers, as well as its temporal variations under year-scale climate changes, are important issues in regard to water resources and ecology environment but are rarely revealed. This study presented a numerical groundwater modeling of the Poyang Lake area to reveal the difference of the temporal variation patterns of the groundwater-lake water interchange and that of the groundwater-river water interchange, and to assess the potential effects of year-scale climate on the temporal-spatial variability of water interchange and on the allocation pattern of the net groundwater discharges into rivers and lake. It is found that the monthly groundwater discharge into surface water exhibits significant temporal variability, which reveals an inverse correlation between monthly groundwater discharge and lake water levels and precipitation amounts. Rainy months can lead to groundwater recharge from the Poyang Lake. Our simulated results reveal that, in the dry year of 2018, the variable monthly groundwater discharge into Poyang Lake and the monthly groundwater recharge from Poyang Lake were 0.97–9.67 × 108 m3/month and 0.07–2.54 × 108 m3/month, respectively. Additionally, the annual water interchange amount between groundwater and the Poyang Lake was 9.44 × 108 m3/year, and the annual net groundwater discharge into Poyang Lake was 6.76 × 108 m3/year. However, the hydraulic interaction between groundwater and the five rivers only features groundwater discharge into rivers with variable monthly groundwater discharge into the five rivers of 0.20–0.72 × 108 m3/month and an annual total groundwater discharge amount of 5.32 × 108 m3/year in 2018. Additionally, our water interchange results of the rainy year of 2010 indicate that the annual water interchange amount between groundwater and the Poyang Lake was 22.74 × 108 m3/year, the annual net groundwater discharge into the Poyang Lake was 1.26 × 108 m3/year, and the annual groundwater discharge into the five rivers was 8.10 × 108 m3/year. These comparisons between the results of the rainy year of 2010 and dry year of 2018 can reveal the effects of the year-scale climate on water exchange between groundwater and surface water and imply that a rainy year can increase the total water interchange amount but decrease the total net groundwater discharge into surface water and that groundwater is more likely to discharge into rivers during a rainy year. Furthermore, it is found that a rainy year can significantly alter the spatial distribution of the water interchange between groundwater and lake water and that the backward particle tracking simulation could be helpful in regard to identifying the spatial distribution of water exchange between groundwater and regional-scale lake. These findings can contribute to a deeper understanding of climate effects on the spatial–temporal variability of water interchange between groundwater and surface water in regional floodplain lake areas and provide useful information for the evaluation of local water resources and the estimation of pollutant transportation.

Technologies for Enhancing Water Productivity through Remote Sensing and GIS

Water is the essential component of the agricultural system as well as another biota so that precisely management needs to save it for the future generation. So many types of water problems are there on the earth to affect the ecosystem whereas some dangerous problems are created by the uneven management of water such as flood, drought, metallic contamination, water pollution, wastage of water, and drainage, etc. Remote sensing and GIS technology are important and useful tools for the sustainable agricultural management system. The integrated use of remote sensing and GIS technology in several areas for the sustainable agricultural management system in India. Even with their importance, data required monitoring the productivity of land and water resources over the vast areas are usually not available or accessible. Satellite measurements from the National Oceanic and Atmospheric Administration (NOAA) weather satellite are combined in this study with the ancillary in situ data into a Geographic Information System (GIS). Remote sensing measurements are converted to crop yield, to actual evapotranspiration and indirectly to the net groundwater use. The GIS data consist of canal-water deliveries and rainfall records. For each of the canal commands, the productivity of water is calculated. Maximum variability in the data is found from different canals commands area in the Indus basin. It has resulted that water productivity is being controlled by the crop yields than by water input. Remote sensing and GIS technology are being effectively utilized in India in several areas for sustainable agricultural development and management. The areas of sustainable agricultural development include cropping system analysis, agro-ecological zonation, quantitative assessment of soil carbon dynamics and soil productivity, soil erosion inventory, integrated agricultural drought assessment and management and Integrated Mission for Sustainable Development (IMSD). Remote Sensing and GIS technology demonstrated to be an effective tool for suggesting action plans or management strategies for agricultural sustainability of any region.

Climate change impacts on crop water productivity and net groundwater use under a double-cropping system with intensive irrigation in the Haihe River Basin, China

Facing the high possibility of future severe water resources scarcity, the Haihe River Basin in the North China Plain is an important region for climate change studies. This study employed an improved SWAT model with a Management Allowed Depletion (MAD) auto-irrigation method to assess the impacts of future climate change on water cycle and crop growth of irrigated winter wheat and summer maize in the Haihe River Basin, China. A total of 27 Global Climate Models (GCMs) from the latest Coupled Model Intercomparison Project 6 (CMIP6) and two Shared Socioeconomic Pathways (SSP2–4.5 and SSP5–8.5) were used to drive the SWAT-MAD model to simulate crop growth and water balance components for two future periods of 2041–2070 (2050s) and 2071–2100 (2080s). Data from almost all GCMs showed an increase in annual mean maximum air temperature, minimum air temperature, total precipitation, and solar radiation across the Haihe River Basin. Winter wheat yields increased by 15.6% (SSP245) and 16.3% (SSP585) by 2050s, and by 17.1% (SSP245) and 10.0% (SSP585) by 2080s, respectively. Summer maize yields increased by 8.9% (SSP245) and 9.6% (SSP585) by 2050s, and by 12.6% (SSP245) and 6.1% (SSP585) by 2080s, respectively. The change of leaf area index (LAI) indicated an advance in phenology of crops, which might be related to the increase in temperature. In the four future climate scenarios, precipitation, percolation, and surface runoff increased by 19.16–57.25 mm, 7.26–22.18 mm, and 1.45–4.87 mm during winter wheat growing season, 125.41–205.24 mm, 51.03–96.37 mm, and 33.97–68.69 mm during summer maize growing season. However, the irrigation amounts decreased by 18.82–83.74 mm and 35.71–50.92 mm during wheat and maize growing seasons, respectively. The annual Net Groundwater Use (NGU) decreased with time and the crop water productivity (CWP) increased in the future, which have positive effects on the sustainable development in this double-cropping system with intensive irrigation management.

Isotope-based water balance assessment of open water wetlands across Alberta: Regional trends with emphasis on the oil sands region

Study regionWater sampling for stable isotopes (18O and 2H) was carried out during 2009–2019 across Alberta, Canada, as part of a survey targeting 1022 open water wetlands. The study presents the first site-specific wetland water balance assessment spanning Grassland, Parkland, Foothills, Mountains, and Boreal regions, including the oil sands region, a corridor of rapid development. Study focusClimate reanalysis, watershed data, and isotopic data for wetlands were incorporated into a steady-state isotope mass balance model, and applied to estimate site-specific evaporation losses from the wetlands, as well as runoff, groundwater inflow, total outflow, and seasonal drawdown. Regional-scale water balance fluxes, water balance indicators and site-specific classifications were mapped and described. New hydrological insights for the regionSystematic variations in evaporation losses, watershed runoff to wetlands, wetland discharge, and net groundwater inflow are revealed across the major subregions of Alberta including the oil sands region. Isotope balance calculations suggest that 13% of wetlands are predominantly evaporative, 87% have surface and/or groundwater outflow, 90% have positive water yields, 47% likely have groundwater inflow, and 2% are apparently fed by allochthonous water sources (either snow or glacial melt). For the 3 oil sands regions, a scoping survey suggests that between 20% and 40% of wetlands within the bitumen zones are detectably groundwater reliant compared to 35–50% in the wider vicinity of the deposits.