Alleviate Water Scarcity Research Articles

How Effective Is Water Technology as a Water Scarcity Remedy for the Economy in China?

China’s water shortage is severe and has become one of the factors hindering economic growth. It is widely accepted that changes in water technology play a profound role in sustainable development. However, because water technology is embedded in water resources, it is difficult to clarify the effects of water technologies as a means of alleviating water scarcity to achieve sustainable development. The level of water technology can be measured by total-factor water efficiency. This study analyzes panel data from 2002–2018 using the stochastic frontier model and addresses water inputs and water technology by introducing the concept of water productivity into economic growth framework. We found that, with the introduction of water technology, the importance of water resources for economic growth increases; water inputs increase by 1%, and GDP increases by 0.349%. The progress of 1% water technology can drive 0.142% of GDP growth and have great potential as a water scarcity remedy for the economy. Due to lower prices, the substitution rate of water technology to water is six times that of water-to-water technology, which is very detrimental to water technology progress. In the short term, water technology can be policy-driven in water-scarce developing economies, and price-induced in the long term.

Water Resources Allocation in the Tingjiang River Basin: Construction of an Interval-Fuzzy Two-Stage Chance-Constraints Model and Its Assessment through Pearson Correlation

Water scarcity has become a major impediment to economic development, and a scientifically sound water allocation plan is essential to alleviate water scarcity. An opportunity constraint approach is introduced to optimise the uncertainty of the minimum regional development level under five hydrological scenarios, and an interval-fuzzy two-stage chance-constraint model (IFTSC) is constructed to improve the reliability of the model results. The correlation of each stochastic parameter in the IFTSC model with the water allocation results and the economic benefits of the Tingjiang River basin is analysed by the Pearson correlation coefficient method. Simulation results from the IFTSC model show a downward trend in overall water scarcity and an upward trend in overall economic benefits in the Tingjiang River basin. Taking the dry water scenario as an example, the water shortage in the industrial sector decreases by 9.7%, and the overall economic benefits of the Tingjiang River basin increase by 41.58 × 108 CNY. The results of the correlation analysis based on Pearson’s correlation coefficient show that water allocation is strongly positively correlated with variables such as water price and regional minimum development requirements, and economic efficiency is strongly positively correlated with unit scale output value and losses caused by water shortage. This paper provides constructive suggestions and guiding directions for the rational allocation of water resources in the Tingjiang River basin through a detailed analysis of the results and identification of the main stochastic parameters in the water allocation process.

Climate induced changes in streamflow and water temperature in basins across the Atlantic Coast of the United States: An opportunity for nature-based regional management

Study regionWatersheds of the Atlantic Coast of the United States (ACUS) spanning a latitudinal range of 30.8°N – 46.5°N Study focusThis study assessed climate-induced changes (CMIP5-RCP 8.5) in projected streamflow and water temperature estimates from individual SWAT watershed models across the ACUS territory by mid and end of the century. Seasonal and spatial trends as well as relationships between hydroclimatologic variables were analyzed to identify opportunities for regional implementation of water management strategies. New hydrological insights for the regionChanges in hydroclimatologic variables suggest spatial trends clearly differentiated by seasons. Northern and central watersheds are projected to experience the most dramatic changes in winter, summer, and spring streamflows (67 %, −25 %, and −24 %, respectively) and summer water temperature (6.2 °C), while southern watersheds presented the largest streamflow increase in fall (35 %), and water temperature changes greater than 3 °C for all seasons. These similarities and contrasts between ACUS watersheds’ hydrologic responses provide an opportunity for regional management of climate induced impacts on water resources. Mitigation strategies such as regional conservation of forests and wetlands can alleviate water scarcity and extreme flow events occurring across the ACUS under the assumed emissions scenario. Results suggest that changes in seasonal air temperature and water temperature may be linearly related in watersheds at lower elevations with no snow influence; while streamflow, precipitation, and air temperature changes have complex non-linear relationships.

Exploration of public stereotypes of supply-and-demand characteristics of recycled water infrastructure - Evidence from an event-related potential experiment in Xi'an, China

There is a growing consensus that recycled water, as an alternative and renewable water source, can serve as a vital water supply to alleviate water scarcity problem and in support of water resilience. Accordingly, recycled water infrastructure investment has seen a significant growth in recent years in many regions of the world. However, previous studies found the perceptions of public, the main end user, toward using recycled water for potable or non-potable purposes remain negatively stereotyped. The negative stereotypes led to public rejections to the construction and operation of recycled water infrastructure. Traditionally, public perceptions of recycled water uses are captured through self-reporting interview or survey techniques. To gain a more accurate measurement of the implicit public stereotypes toward recycled water uses, this study employed an event-related potential (ERPs) technique to collect neurophysiological responses with participants and presented a few research findings. Firstly, the negative stereotypes of recycled water still exist. Secondly, the degree of human contact impacts the negative stereotypes of participants toward recycled water uses more significantly on the supply side (referring to the whole supply chain of recycled water) rather than on the demand side (referring to the potential consumers of recycled water) Third, knowledge level significantly impacts the negative stereotypes of participants toward recycled water uses that have close human contact, at both supply and demand sides, and shows a more significant impact on the supply side. The findings of study contributed to the literature through creatively dividing the negative stereotypes of recycled water into the “supply-side” and the “demand-side” ones, and meanwhile have managerial implication for policymaking and scheme implementation in the area.

Water-use technical efficiency and income: Evidence from China's South-North Water Transfer Project

Improvements in water-use technical efficiency can alleviate water scarcity, which may help alleviate poverty caused by it. Therefore, it is necessary to understand the complex relationship between water-use technical efficiency, income, and even poverty. This article explores the spatial spillover effect of water-use technical efficiency on income through the case of China's South-North Water Transfer Project. It also critically examines the role of industrial development and employment in the impact of water-use technical efficiency on income. The findings demonstrate that increasing water-use technical efficiency can increase income, bringing “water blessings.” Moreover, increasing water-use technical efficiency also improves the income of adjacent regions through spatial spillovers. In addition, increasing water-use technical efficiency promotes industrial development, thereby increasing income through the positive moderation of government expenditure. Finally, increasing water-use technical efficiency also promotes employment and then increases income; however, increasing population size weakens WUTE's impact on employment. Beyond the current understanding of the relationship between water-use technical efficiency and income, this article provides another empirical study that contributes to profoundly understanding the spatial effect and internal mechanism of this relationship.

Sustainable management of two‐directional lateral and upconing saltwater intrusion in coastline aquifers to alleviate water scarcity

AbstractLateral saltwater intrusion (LSWI) and vertical saltwater intrusion (VSWI) are the major problems in coastal aquifers. Coastal aquifers are subjected to natural and artificial changes, including sea‐level rise, decreasing inland recharge, and overexploitation of production wells' water resources. Therefore, this study investigates the influence of changing the coastal aquifers boundary conditions considering climate changes' effect. Parameters describing the upward saline well parameters based on the abstraction conditions, also, the top layer properties were studied based on the erosion and sediments, irrigation, and drainage conditions. For this purpose, the SEAWAT model was employed to simulate lateral SWI based on Henry's problem principle. The sensitivity analysis of the mentioned parameters was accomplished considering as a case study the Biscayne aquifer in the Cutler Ridge area near Deering Estate, Florida, USA, where the LSWI and VSWI were also investigated. The results indicate that the boundary conditions, abstraction well parameters, and top layer cost significantly impact aquifer LSWI and water upconing. The simulation results of the Biscayne aquifer for a saline water head of 84.86 cm for 2060 indicate a decrease in freshwater recharge by 30% and increasing the saltwater concentration by 14.30%. At the same time, the LSWI increased by 3.30%, 22.80%, and 8.70%, while the relative upconing heights reached 0.63, 0.60, and 0.47 compared with 0.42 for the current situation. Increasing the upward saline abstraction well discharge rates by 50% increases the LSWI by 9.40%. In contrast, increasing the depth by 10%; decreases the distance by 30%, the screen length by 30%, the LSWI decreased by 1.80%, 25.10%, and 1.30%, respectively. At the same time, the relative VSWI height reached 0.60, 0.39, 0.48, and 0.40, respectively. Moreover, decreasing the top layer hydraulic conductivity by 25% and increasing the aquitards layer depths by 200% decreased the LSWI by 4.90% and 7.80%, respectively. At the same time, the relative VSWI height reached 0.34 and 0.30, respectively. In addition, the saline water heads, a freshwater recharge should be controlled to manage SWI; the upward well should be utilized at a low abstraction rate, far from the seaside, and with minimum screen length. The agriculture activity for decreasing the soil permeability for the top layer must be extended for better management of the SWI. The solution‐oriented findings resulting from this study might be useful for decision‐makers and engineers to develop effective management measures to tackle the SWI issue in coastal aquifers.

Spatial Variation in the Composition and Diversity of Fishes Inhabiting an Artificial Water Supply Lake, Eastern China

With the intensification of eutrophication, many artificial water supply lakes that act as a biological filter for water diverted from rivers have been built to alleviate water scarcity in Eastern China. In this study, we selected Lake Yanlong, a representative artificial water supply lake in Yancheng City, as our experimental lake to explore how the community composition of fishes changed among different habitat types and assess potential consequences for effective water treatment. From October 2015 to October 2020, we conducted quarterly surveys of fish communities and environmental factors in the Mangshe River (MR; water for lake) compared to four different water treatment zones of Lake Yanlong (PZ, the pretreatment zone with inlet from the MR; EZ, the emergent macrophyte zone; SZ, the submerged macrophyte zone; DZ, the deep purification zone with outlet to urban waterworks). A total of 16,339 individual fish belonging to 11 families and 49 species were collected. Six of the eight dominant species observed across zones were small-bodied fishes. Despite reduced fish species richness, the relative abundance and biomass of fishes tended to be higher in Lake Yanlong relative to the MR. The Shannon-Wiener diversity index, Pielou evenness index, Simpson’s diversity index all decreased from the MR to the DZ in the following sequence: MR < PZ < EZ < SZ < DZ. Analysis of similarities and similarity percentage analysis confirmed that fish communities differed significantly among zones and Coilia ectenes, Carassius auratus, Pseudobrama simony, Hemiculter leucisculus, and Hemiculter bleekeri were the major differentiating species. Mantel’s test and redundancy analysis revealed that water depth, aquatic vegetation coverage, and phytoplankton concentrations were the major factors determining the spatial distribution of fishes when moving from the MR to the DZ of Lake Yanlong. Stocking piscivorous fish can be used as an effective measure to control the abundance of prolific small-bodied fishes in Lake Yanlong. The details backing these findings are important for understanding how the community composition of fishes among habitat types in Lake Yanlong influence water quality, and to develop suitable biomanipulation strategies for the management of fish resources and maintaining proper function of these artificial water supply lakes.

A Transition Towards an Unusually Wet Condition Will Not Alleviate Water Scarcity Risk in Xinjiang, China

AbstractThe arid Xinjiang region of China exemplifies severe water scarcity regions with a burgeoning agriculture. Whether or not the ongoing wetting, unprecedented in instrumental hydroclimatic records, will become routine has implications for regional oasis economy and China's Go West plan. Here, we show that Xinjiang experienced a one‐third increase in precipitation since the 1980s, and that this increase is primarily due to sea surface warming in the Bay of Bengal‐west Pacific and tropical North Atlantic. Using the historical precipitation‐sea surface temperature relationship to constrain future precipitation changes under a moderate warming scenario, annual precipitation over Xinjiang is projected to increase by 56% relative to the present‐day, and the levels of wetness of exceptional years, such as 2010 and 2016, will potentially become a new norm in terms of regional mean within the next few decades. However, such a large precipitation‐induced increase in freshwater resources will still be insufficient to rescue the Tarim and Junggar basins from their severe water scarcity dilemma within the next few decades, unless the most‐efficient water‐saving irrigation strategies are implemented.

Simulation Analysis of Double-effect Seawater Desalination System Using Compression Heat Pump

The lack of freshwater resources has become the biggest obstacle to the sustainable development of the world economy with the expansion of population and the impact of climate change. Seawater desalination is recognized as the most effective means to alleviate water scarcity. A double-effect seawater desalination system using compression heat pump is proposed by combining a compression heat pump and a double-effect desalination system. Performances of the proposed system are simulated using Aspen simulation software. Based on the simulation results, the influence of heat pump evaporating/condensing temperature, temperature difference between the two effects and the brine circulation ratio on the system Performance Ratio (PR) and freshwater production are analysed. It is concluded that the value of PR increases but the freshwater production reduces with the increase of evaporating temperature of the heat pump. Both the value of PR and the freshwater production decreases with the condensing temperature of the heat pump. An optimal temperature difference between the two effects exits to get the highest PR and freshwater production for a constant heat pump operation condition. The freshwater production can increase slightly with the increase of the brine circulation ratio. When the mass flow rate of feed seawater is 80kg/h and the evaporation temperature of primary effect evaporator is 40°C, the PR of the system reaches 40.07 with an evaporating/condensing temperature of 20°C/50°C. The freshwater production is 39.76kg/h with an evaporating/condensing temperature of 10°C/50°C.

Public perception of water re-use: building trust in alternative water sources in Malmesbury, South Africa

The recent drought in the Western Cape Province in South Africa has been marked as the worst since 1904. The drought impacted severely on the availability of bulk water supply in many parts of the Western Cape Province, particularly the Cape Town Metro and surrounding districts. In order to alleviate water scarcity, wastewater recycling (water reuse) has been identified to have the potential to augment water supplies in the province. This paper argues that although water recycling has the potential to contribute towards alleviating water scarcity, studies have shown that public perceptions greatly influence the outcome of any water recycling scheme. The study collected data using face-to-face interviews, focus group discussions, and the application of the Story with a Gap participatory exercise. One of the key findings is that residents have to trust the municipal competencies and systems, and this can be achieved through meaningful engagement between the municipality and residents. We argue that rolling out a water reuse scheme by starting with affluent areas increases the likelihood of acceptance among low-income communities.

Online monitoring and sampling analysis of siltation in the middle route of the south-to-north water diversion project

The middle route project (MRP) of the South to North Water Diversion Project is a significant infrastructure and alleviating water scarcity in Northern China. MRP suffered from untraditional siltation problems. Obvious siltation occurred in the regulating reservoir at the end of the channel and some locations with weak hydrodynamic conditions in the channel when the mineral siltation concentration in the flow is very low. To study the characteristics of the siltation and the siltation time period, an IoT based automatic siltation monitoring system using cloud was installed at the outlet of the inverted siphon project on Xiao River. Three years of online monitoring data since 2018 and the siltation samples at five sites for particle size analysis were collected. The monitoring data shows that siltation mainly occurs during March to October, and almost no siltation occurs in winter. The maximum siltation speed can reach 390 mm per day. The particle size of the siltation gradually increases from upstream to downstream, which mainly occurs in the range above 100 m. The organic matter contained in the siltation shows a significant increase from 40.3 to 86.4% at upstream and downstream sampling position, respectively. Monitoring results shows the main body of the siltation in the MRP is not the traditional siltation but the remnants of the algae that proliferate in large numbers. During March to October, the temperature is suitable for the proliferation of algae which attaches to the sediment particles and gradually grows downstream with the flow.

Response of Potted Hebe andersonii to Salinity under an Efficient Irrigation Management

Although the use of marginal-quality water can be an effective measure to alleviate water scarcity, it often contains a high concentration of salts that can compromise crop growth. As a result, farmers apply more water than necessary to leach salts away from the root zone, resulting in wasted water and the release of fertilizers into the groundwater. In this study, we assessed the effects of three salinity levels of irrigation water (1.8 dS m−1, 3.3 dS m−1, and 4.9 dS m−1) on the physiology and ornamental traits of Hebe andersonii cv. Variegata. The experiment was carried out with potted plants in a greenhouse for seven months. We also studied the feasibility of growing this cultivar without leaching salts. The results showed that Hebe plants can be grown without leaching using water up to 3 dS m−1. This setup produces plants with high water use efficiency and without reducing their ornamental value. Meanwhile, irrigation with 5 dS m−1 water reduced the quality of Hebe but did not compromise its physiological processes. The photosynthesis of Hebe under salinity conditions was mainly controlled by stomata, which was related to the level of salt stress and water status of the plant. Salinity had no significant effects on photosystem II, which can be explained by the fact that Hebe was able to dissipate the excess excitation energy as heat effectively. Hebe was able to avoid ion toxicity and maintain a suitable nutrient balance under the salinity levels tested in this experiment.

Salinity impacts on irrigation water-scarcity in food bowl regions of the US and Australia

Irrigation water use and crop production may be severely limited by both water shortages and increased salinity levels. However, impacts of crop-specific salinity limitations on irrigation water scarcity are largely unknown. We develop a salinity-inclusive water scarcity framework for the irrigation sector, accounting for crop-specific irrigation water demands and salinity tolerance levels and apply it to 29 sub-basins within two food bowl regions; the Central Valley (CV) (California) and the Murray–Darling basin (MDB) (Australia). Our results show that severe water scarcity (levels >0.4) occurs in 23% and 66% of all instances (from >17 000 monthly crop-specific estimates) for the CV and MDB, respectively. The highest water scarcity levels for both regions occurred during their summer seasons. Including salinity and crop-specific salinity tolerance levels further increased water scarcity levels, compared to estimations based on water quantity only, particularly at local sub-basin scales. We further investigate the potential of alleviating water scarcity through diluting surface water with lower saline groundwater resources, at instances where crop salinity tolerance levels are exceeded (conjunctive water use). Results from the CV highlights that conjunctive water use can reduce severe water scarcity levels by up to 67% (from 946 monthly instances where surface water salinity tolerance levels were exceeded). However, groundwater dilution requirements frequently exceed renewable groundwater rates, posing additional risks for groundwater depletion in several sub-basins. By capturing the dynamics of both crops, salinity and conjunctive water use, our framework can support local-regional agricultural and water management impacts, on water scarcity levels.

Winter Potato Water Footprint Response to Climate Change in Egypt

The limited amount of freshwater is the most important challenge facing Egypt due to increasing population and climate change. The objective of this study was to investigate how climatic change affects the winter potato water footprint at the Nile Delta covering 10 governorates from 1990 to 2016. Winter potato evapotranspiration (ETC) was calculated based on daily climate variables of minimum temperature, maximum temperature, wind speed and relative humidity during the growing season (October–February). The Mann–Kendall test was applied to determine the trend of climatic variables, crop evapotranspiration and water footprint. The results showed that the highest precipitation values were registered in the northwest governorates (Alexandria followed by Kafr El-Sheikh). The potato water footprint decreased from 170 m3 ton−1 in 1990 to 120 m3 ton−1 in 2016. The blue-water footprint contributed more than 75% of the total; the remainder came from the green-water footprint. The findings from this research can help government and policy makers better understand the impact of climate change on potato crop yield and to enhance sustainable water management in Egypt’s major crop-producing regions to alleviate water scarcity.

Coupling Two-Stage Stochastic Robust Programming with Improved Export Coefficient for Water Allocation among Industrial Sectors

Water scarcity and water pollution are essential factors limiting coordinated regional development, especially in water-deprived regions. Industrial restructuring is an effective water management solution to alleviate water scarcity and mitigate water pollution. However, due to widely existing inexact parameter information in the water resource management system, it is challenging to allocate water resources among industrial sectors. To address these problems, an export coefficient coupled with a two-stage stochastic robust programming method (EC-TSRP) was developed through integrating an export coefficient model (ECM), two-stage stochastic programming (TSP) and robust optimization. The proposed EC-TSRP model could effectively deal with the multiple uncertainties expressed as stochastic and the intervals with fluctuation ranges, and enhance the robustness of optimal plans for supporting water resource allocation among industrial sectors under complex uncertainties. It was then applied to Bayan Nur City, in arid north-west China. The optimization alternatives indicate that wheat, sheep and services would be the most sensitive sectors among all industrial sectors, when non-point source (NPS) pollution exports are restricted. In addition, comparing the EC-TSRP results with the deterministic model, the reliability of the system could be improved significantly, while the value of the objective function would be decreased slightly. The simulation results were also compared with the historical data from 2012 to 2016. Although the total revenue of Bayan Nur City would decrease by 1.52%, the pollutant loads of total nitrogen, total phosphorus and chemical oxygen demand (TN, TP and COD) would decrease by 14.5%, 7.75% and 2.07%, respectively, and total water allocation also would decrease from 4.6 billion m3 to 4.23 billion m3.

A novel concentrated solar membrane-distillation for water purification in a building integrated design

Solar-assisted Vacuum Membrane-Distillation provides a lower-energy alternative to water treatment, particularly desalination in dry areas. While horizontally integrated (roof-top) decentralized treatment systems exist, vertically integrated (balcony) water treatment systems remain unexplored. This study improves upon a previous solar-VMD system with a compound parabolic collector and integrate it onto the vertical faces of a building. The novel VMD system generates a flux of >8 L water per square meter of membrane area per hour when operating at a temperature above 65 °C and with a 15 kPa vacuum pressure during peak solar conditions (>800 W/m2). This system's performance was identical under clean-water and desalination operating modes, reinforcing the use-case of urban desalination. Furthermore, a numerical model was developed and validated to be utilized for parametric study. Finally, an economic analysis has shown that the system has a levelized cost of water of 21.5 USD/m3, with the cogeneration of heat via hot water (i.e., a levelized cost of heat of 0.015 USD/kWh) off-setting costs. Assuming a use-case of rural implementation whereby water transport costs dominate, the payback period of the design is around 2 years. Ultimately, this demonstrates a viable decentralized water treatment/hot-water system that can alleviate water scarcity in arid areas.

RZWQM2 Simulated Drip Fertigation Management to Improve Water and Nitrogen Use Efficiency of Maize in a Solar Greenhouse

The drip fertigation technique is a modern, efficient irrigation method to alleviate water scarcity and fertilizer surpluses in crop production, while the precise quantification of water and fertilizer inputs is difficult for drip fertigation systems. A field experiment of maize (Zea mays L.) in a solar greenhouse was conducted to meet different combinations of four irrigation rates (I125, I100, I75 and I50) and three nitrogen (N) fertilizer rates (N125, N100 and N75) under surface drip fertigation (SDF) systems. The Root Zone Water Quality Model (RZWQM2) was used to assess the response of soil volumetric water content (VWC), leaf area index (LAI), plant height and maize yield to different SDF managements. The model was calibrated by the I100N100 scenario and validated by the remaining five scenarios (i.e., I125N100, I75N100, I50N100, I100N125 and I100N75). The predictions of VWC, LAI and plant height were satisfactory, with relative root mean square errors (RRMSE) < 9.8%, the percent errors (PBIAS) within ±6%, indexes of agreement (IoA) > 0.85 and determination of coefficients (R2) > 0.71, and the relative errors (RE) of simulated yields were in the range of 1.5–7.2%. The simulation results showed that both irrigation and fertilization had multiple effects on water and N stresses. The calibrated model was subsequently used to explore the optimal SDF scenarios for maximizing yield, water use efficiency (WUE) or nitrogen use efficiency (NUE). Among the SDF managements of 21 irrigation rates × 31 N fertilizer rates, the optimal SDF scenarios were I120N130 for max yield (10516 kg/ha), I50N70 for max WUE (47.3 kg/(ha·mm)) and I125N75 for max NUE (30.2 kg/kg), respectively. The results demonstrated that the RZWQM2 was a promising tool for evaluating the effects of SDF management and achieving optimal water and N inputs.

Improving footprint-based water use efficiency through planting structure optimization

Unreasonable utilization of water resources cause serious water shortage and associated pollution problems. Improving water use efficiency (WUE) is helpful for alleviating water scarcity and mitigating water pollution. However, due to the conflict between water saving and economic development as well as uncertain parameter information, it is challenging to improve WUE. To address these problems, a water-footprint-based interval fuzzy robust fractional programming (WF-IFRFP) model was developed through integrating water footprint (WF), interval parameter programming (IPP) and fuzzy robust optimization (FRP) into a fractional programming (FP) framework. The developed WF-IFRFP model improved upon traditional methods by being able to tackle interval numbers and fuzzy sets under different system-violation risks. The developed model was applied to a water management case in the northwest of Inner Mongolia, China. The results of WF assessment showed that the water consumption of crop growth increased, water, whereas that used for reducing total nitrogen concentration decreased from 2012 to 2016. Then, specific benefit- and risk-explicit plans for cropping pattern adjustments were generated. The results showed that the water supply-demand ratio from WF-IFRFP would be [5.1, 10.7] % higher than that in the benchmark year of 2016. To assess its performance and merits, the optimal results from the WF-IFRFP model were compared to four alternative models. These comparisons reveal that the WF-IFRFP model is beneficial for improving irrigation WUE.

Determination of Potential Aquifer Recharge Zones Using Geospatial Techniques for Proxy Data of Gilgel Gibe Catchment, Ethiopia

The lack of valuable baseline information about groundwater availability hinders the robust decision-making process of water management in humid, arid, and semi-arid climate regions of the world. In sustainable groundwater management, identifying the spatiotemporal and extrapolative monitoring of potential zone is crucial. Thus, the present study focused on determining potential aquifer recharge zones using geospatial techniques for proxy data of the Gilgel Gibe catchment, Ethiopia. Proxy data are site information derived from satellite imageries or conventional sources that are operated as a layer attribute in the geographical information system (GIS) to identify groundwater occurrence. First, GIS and analytical hierarchy process (AHP) were applied to analyze ten groundwater recharge controlling factors: slope, lithology, topographic position index lineament density, rainfall, soil, elevation, land use/cover, topographic wetness index, and drainage density. Each layer was given relative rank priority depending on the predictive implication of groundwater potentiality. Next, the normalized weight of thematic layers was evaluated using a multi-criteria decision analysis AHP algorithm with a pairwise comparison matrix based on aquifer infiltration relative significance. Lithology, rainfall, and land use/cover were dominant factors covering a weight of 50%. The computed consistency ratio (CR = 0.092, less than 10%) and consistency index (CI = 0.1371) revealed the reliability of input proxy layers’ in the analysis. Then, a GIS-based weighted overlay analysis was performed to delineate very high, high, moderate, low, and very low potential aquifer zones. The delineated map ensures very high (29%), high (25%), moderate (28%), low (13%), and very low (5%) of the total area. According to validation, most of the inventory wells are located in very high (57%), high (32), and moderate (12%) zones. The validation results realized that the method affords substantial results supportive of sustainable development and groundwater exploitation. Therefore, this study could be a vigorous input to enhance development programs to alleviate water scarcity in the study area.

Robust PEDOT:PSS-based hydrogel for highly efficient interfacial solar water purification

Solar water purification has been attracting considerable attention due to its promising desalination and purification applications to alleviate water scarcity and pollution. However, despite recent rapid progress, rational design and development of robust and highly efficient interfacial photothermal materials sufficing for large scale real usage is still a critical challenge to the science and technology of this field. Herein, we develop a mechanically robust nanocomposite hydrogel with intriguing evaporation performance by simple blending and cross-linking of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) nanofibrils and poly(vinyl alcohol) (PVA) viscous solution. As-prepared PEDOT:PSS-PVA hydrogel exhibits an excellent light absorption ratio of ∼ 99.7% in a wide wavelength range of 250 ∼ 2500 nm and displays unprecedented high energy efficiency of ∼ 98.0% with a fast evaporation rate of ∼ 2.84 kg m-2 h-1 under one sun irradiation. A 60-day continuous test simulating the real seawater evaporation environment shows superior long-term stability of such hydrogel with an average energy efficiency of ∼ 93.3%. To harness these advantageous properties, we further demonstrate the scalable hydrogel production and fabricate a solar water evaporator equipment for seawater desalination and wastewater purification, from which the acquired water can meet the drinking requirements set by the World Health Organization.