Search Results (245)

Seawater has been widely used in copper–molybdenum flotation plants due to the shortage of fresh water and the high cost of seawater desalination, especially in arid regions. There have been many studies concerning the molybdenite flotation in seawater. Due to the complication of seawater flotation, it is difficult to identify the key factors affecting molybdenite recoveries. It is known that the unique structure of molybdenite plays an important role in molybdenite flotation. The anisotropic property of molybdenite leads to the different surface properties of basal and edge plane surfaces. Electrochemical properties of sulfides have a significant effect on the surface properties which affect the flotation performance. Therefore, it is important to understand the surface electrochemical properties such as surface chemistry, redox processes, and reaction kinetics of molybdenite’s two different surfaces in seawater, and to determine what affects the molybdenite flotation behaviors in seawater. In this study, the surface properties of molybdenite basal and edge plane surfaces in both fresh water and seawater were investigated through various electrochemical techniques. Open circuit potential (OCP) measurement indicated that edge plane surfaces were easier to be oxidized than basal plane surfaces. Cyclic voltammetry (CV) studies showed that the basal plane surfaces were stable with a low electrochemical reactivity, while the edge plane surfaces had relatively high electrochemical reactivity. In addition, the redox property of the molybdenite surface was enhanced in seawater, which is a key to the improvement of fine molybdenite flotation in seawater. Electrochemical impedance spectroscopy (EIS) measurements further confirmed the stability of basal plane surfaces and indicated a greater charge transfer ability of edge plane surfaces in seawater. Different molybdenite particle sizes with different basal and edge ratios were applied in the flotation in both fresh water and seawater; the results illustrated that molybdenite flotation was enhanced in seawater especially to fine particles. The flotation and electrochemical studies reveal that the electrochemical reactivity of edge plane surface plays an important role in molybdenite seawater flotation. Full article

Pressure on fresh water resources has been aggravated in recent decades, basically due to population growth, rapid urbanization, and global warming. Integrated engineering solutions and the circular economy, considering the urban water cycle as a whole, are becoming fundamental, particularly in arid and semi-arid regions under permanent or recurrent hydric deficit. This study aims to develop and present an integrated engineering solution for water supply, wastewater collection, and treated wastewater reuse for landscape irrigation in a large, topographically complex, and arid to semi-arid coastal urban region at the south of Santiago Island, Cape Verde. The region is one of the driest and most arid of the Island, with a current average annual precipitation between about 100 and 200 mm, and has very limited underground water resources. The main study area, with about 600 ha, has altitudes ranging from values close to sea level up to about 115 m and has several topographic difficulties, including several relatively rugged zones. The devised water supply system considers four altimetric distribution levels, three main reservoirs connected to each other by a serial system of pipelines with successive pumping, a fourth downstream reservoir for pressure balance in one of the levels, and desalinated water as the source. The sanitary sewer pipes of the urbanizations drain to an interceptor system that operates predominantly in open channel flow in a closed pipe. The long interceptor crosses laterally along the coast several very dug valleys in the path to the Praia Wastewater Treatment Plant in the east, and requires several conduits working under pressure for the crossings, either lifting or governed by gravity. The under-pressure pipeline system of recycled water is partially forced and partially ruled by gravity and transports the treated wastewater from the plant in the opposite direction of the interceptor to a natural reservoir or lake located in the region of urbanizations and the main green spaces to be irrigated. The conceived design of the interceptor and recycled water pipeline minimizes the construction and operation costs, maximizing their hydraulic performance. Full article

Water scarcity and inefficient nitrogen (N) use are major constraints on wheat production in arid regions. Drip irrigation offers a precise method for optimizing water and nutrient delivery, but integrated management strategies are needed to maximize yield and resource use efficiency. In Egypt, water shortages and inadequate fertilizer necessitate effective resource management for sustainable agriculture and crop productivity. This study investigates the effects of integrated water and nitrogen fertilizer management under drip irrigation on wheat (Triticum aestivum L.) performance in arid zones of Egypt. A two-year field experiment was conducted to evaluate wheat yield, productivity of applied water (PAW), crop water productivity (CWP), and nitrogen use efficiency (NUE) under varying irrigation regimes and nitrogen application rates. This study evaluated two irrigation regimes: 100% (I₁) and 80% (I₂) of crop evapotranspiration (ETc) in combination with three nitrogen application rates: 142.8 kg N ha⁻¹ (N₁), 190.4 kg N ha⁻¹ (N₂), and 238 kg N ha⁻¹ (N₃). Irrigation at 100% of ETc (I₁) significantly enhanced plant height, straw yield, biological output, grain yield, seed index, NUE, and CWP in comparison with the 80% ETc treatment (I₂). However, I₂ demonstrated a higher PAW and grain protein content than I₁. Furthermore, applying nitrogen at a rate of 238 kg N ha⁻¹ (N₃) resulted in notable improvements in these parameters relative to the lower rate of 142.8 kg N ha⁻¹ (N₁). I₁N₃ and I₁N₂ treatments increased CWP by 29% and 22%, respectively, compared to I₁N₁ across both growing seasons. Principal component analysis (PCA) revealed that the application of 238 kg N ha⁻¹ (N₃) may represent the most effective nitrogen management strategy for optimizing winter wheat production under drip irrigation systems. Moreover, PCA suggested that combining deficit irrigation with a high nitrogen application rate (I₂N₃) enhances the productivity of applied water (PAW) and grain quality. In contrast, full irrigation with the lowest nitrogen rate (I₁N₁) appeared to be the most effective strategy for maximizing NUE. These findings highlight the potential of integrated strategies to sustainably boost wheat yields in environments suffering from water shortage. Full article

Climate change intensifies the challenges surrounding water cycling and vegetation dynamics in arid desert ecosystems, calling for detailed observations to decode adaptive plant strategies and support restoration efforts. This study analyzes interannual variations in water budgets and vegetation coverage in two distinct desert systems—K. foliatum (midstream) and R. songarica (downstream)—within the Heihe River Basin from 2016 to 2021. We uncover a pronounced ecohydrological contrast: the K. foliatum ecosystem displays substantial soil moisture variability alongside high precipitation and evapotranspiration rates, leading to a soil water deficit. In contrast, the R. songarica ecosystem maintains minimal moisture fluctuation under extreme aridity, yet records a slight water surplus. Notably, vegetation coverage in K. foliatum closely correlates with soil water storage, precipitation, and evapotranspiration, whereas R. songarica exhibits no significant hydrological coupling, implying a pulsed response to episodic rainfall. Groundwater recharge emerges as a key compensatory mechanism against rainfall shortages in midstream regions. These findings underscore the need for region-specific management—prioritizing groundwater conservation downstream and intelligent irrigation regulation midstream—offering a science-backed pathway for restoring and managing water resources in arid inland basins under climate change. Full article

Droughts present persistent and severe challenges to the security of regional water supplies, particularly in arid and semiarid regions such as northern China. Traditional reservoir operation models that prioritize water supply reliability or economic efficiency often fail to adequately address the risks posed by extreme drought events. In this study, we develop a novel risk-informed multiobjective reservoir operation model that incorporates three key performance indicators: reliability, resilience, and vulnerability (RRV). This model aims to improve drought response and enhance the overall stability of the water supply system. It is applied to a multisource water supply system composed of the Nierji Reservoir and various water-user sectors. Unlike traditional models, this approach explicitly balances the trade-offs among supply reliability, recovery capability, and water shortage during drought periods. Comparative analyses with conventional strategies (CSs) under both a six-year consecutive dry period and a representative single dry year demonstrate the superior performance of the RRV-based model in drought management. Specifically, the model reduces the average supply disruption duration from 8–10 to 4–6 ten-day intervals, increases water supply reliability to 90%, decreases the maximum single-event shortage depth to 22 × 10⁶ m³, and lowers the average water shortage to 221 × 10⁶ m³. Agricultural water shortages are reduced, although slight increases occur in other sectors. The results highlight resilience as the most influential objective in the model, and its inclusion or exclusion can be adjusted based on different drought response priorities. This study presents a novel and adaptive framework for reservoir operation under drought conditions, offering practical implications for improving the resilience and efficiency of regional water resource systems in the context of climate change. Full article

Effective water governance is essential for sustainable development amidst water scarcity challenges in semi-arid regions like Esmeraldas Province, which has substantial agrotourism potential. Yet, fragmented governance and chronic water shortages threaten its viability. Using a mixed-method approach, this study analyzed how sustainable water governance can support agrotourism development in Esmeraldas Province, Ecuador. This study combined policy gaps analysis, stakeholder surveys (policymakers, farmers, community leaders, and tourism operators), and water availability using the Standardized Precipitation Evapotranspiration Index (SPEI) from 1980 to 2022. The results revealed a lack of policy regulation and water infrastructure as the major governance gaps that need more intervention. The survey respondents indicated that water is mainly used for domestic and economic activities and the conservation of natural ecosystems. The SPEI revealed a significant drought trend falling below −3, with severe drought years coinciding with many crop losses and a fall in tourism. This study highlights the interconnection between water governance and agrotourism in Esmeraldas, Ecuador, proposing a strategic framework that incorporates adaptive governance principles and inclusive participation mechanisms, emphasizing targeted capacity building to strengthen water management practices and enhance the Sustainable Development Goals for agrotourism resilience. Full article

Sustainable land management in arid regions such as the Jordan Valley (JV) is essential as climate pressures and water shortages intensify. The extended use of treated wastewater (TWW) for irrigation, while necessary, brings potential risks related to the accumulation of trace elements and their impact on soil health and food safety. This study examined the spatial distribution, variability, and potential sources of five trace elements (Co, Hg, Mo, Mn, and Ni) in agricultural soils across a 305 km² area. A total of 127 surface soil samples were collected from fields irrigated with either TWW or freshwater (FW). Trace element concentrations were consistently higher in TWW-irrigated soils, although all values remained below WHO/FAO recommended thresholds for agricultural use. Spatial modeling was conducted using both ordinary kriging (OK) and empirical Bayesian kriging (EBK), with EBK showing greater prediction accuracy based on cross-validation statistics. To explore potential sources, semivariogram modeling, principal component analysis (PCA), and hierarchical clustering were employed. PCA, spatial distribution patterns, correlation analysis, and comparisons between TWW and FW sources suggest that Co, Mn, Mo, and Ni are primarily influenced by anthropogenic inputs, including TWW irrigation, chemical fertilizers, and organic amendments. Co exhibited a stronger association with TWW, whereas Mn, Mo, and Ni were more closely linked to fertilizer application. In contrast, Hg appears to originate predominantly from geogenic sources. These findings provide a foundation for improved irrigation management and fertilizer application strategies, contributing to long-term soil sustainability in water-limited environments like the JV. Full article

Water resources are a key constraint on sustainable development in arid regions, especially for agricultural production where water use is intensive. To assess the sustainability of agricultural water use in such environments, this study utilizes 2010–2020 agricultural data from the Turpan–Hami Basin and is among the first to integrate the water footprint (WF) theory with the DPSIR (driver–pressure–state–impact–response) model into a comprehensive framework for evaluating water resource sustainability in arid agricultural systems. The agricultural blue, green, and grey WF in the Turpan–Hami Basin were quantified for 2010–2020, followed by a sustainability assessment under the DPSIR framework using a comprehensive weighting method. The results showed a continuous increase in the WF, dominated by the blue WF (>60%), largely due to crops like cotton and grapes, intensifying regional water stress. Turpan experienced prolonged resource overload, while Hami exhibited slightly higher sustainability. DPSIR analysis revealed stronger policy responses in Turpan and significant ecological investments in Hami. Key influencing factors included the crop yield, WF modulus, per capita WF, and water quality shortage index. Overall, sustainability in the basin fluctuated between “Basically Sustainable (Level III)” and “Insufficiently Sustainable (Level IV)”, with slight improvement in 2020. The findings highlight the need for region-specific agricultural optimization, strengthened ecological governance, and improved water-saving strategies to enhance water use efficiency and sustainability in arid regions. Full article

Large-scale inter-basin water transfer is an important means to alleviate the pressure on water resources in water shortage regions. However, the long-term impacts of inter-basin transfers on the regional water–salt balance and associated land productivity remain poorly understood, especially in salt-affected arid environments. To fill this gap, the core objective of this study was to reveal the implications of inter-basin water transfer on soil salinity and sodicity and the crop yield response under different irrigation practices. We conducted a case study on the Karamay irrigation district (KID), an artificial oasis with a 30-year history of inter-basin water transfer in northwestern China, using trend and correlation analyses, water–salt balance analyses, and salt-controlled yield reduction functions as well as field comprehensive measurements over 1996–2023. The results indicate that soil salinity and sodicity profiles, overall, exhibited a clear vertical stratification under both the early and late crop growing stages, and the degree of the soil salinization was decreasing, and the area of non-saline land was increasing significantly from 1996 to 2023 in the KID. Owing to the lack of salt-washing water and the poor irrigation water quality, the water-saving irrigated farmland was in the slight salt-aggregating state in the topsoil layer, while the other soil layers were in the salt-expelling or salt-equilibrating state in the KID. The profile distribution and exchange fluxes of soil salinity and sodicity are mainly characterized by climate, irrigation, and groundwater dynamics, as well as the plant salt tolerance, soil properties, and agronomic management which also influence the soil salt accumulation. With the transformation of irrigation schemes from traditional flood irrigation to modern water-saving irrigation during 1996–2023, the impact of soil salinity on relative crop yields has been substantially reduced in the KID, especially for salt-sensitive crops. This revealed that optimizing the drainage facilities, precise field irrigation and fertilization measures, and rational crop selection and agronomic practices are vital for high-quality development in the KID. Capitalizing on these research findings, we would provide effective directives for maintaining the sustainability of agricultural development in other similar inter-basin water transfer zones in the world. Full article

Ensuring water resources for livestock production in Kazakhstan presents a multifaceted challenge. Pastoral systems in Southern Kazakhstan are facing a critical groundwater shortage, with 56.5% of pastures currently unused due to limited water access, jeopardizing around 2 million head of livestock and the region’s food security. This study presents the first comprehensive groundwater assessment in over 40 years, integrating hydrochemical analysis (55 samples) and field surveys conducted in the Almaty and Zhetysu regions. Key findings include: the total water demand for livestock is estimated at 53,735 thousand m³/year, with approximately 40% of samples exceeding WHO guidelines for total mineralization. It was determined that 45% of exploitable groundwater reserves in the Almaty region and 15–17% in the Zhetysu region are suitable for irrigation. This study also provides updated hydrogeological data, identifying three priority aquifer systems. A novel Groundwater Sustainability Index for pastoral zones of Central Asia is introduced, demonstrating that strategic aquifer development could expand watered pastureland by 30–40%. These findings directly inform Kazakhstan’s Agricultural Development Plan through 2030 and provide a replicable framework for sustainable water management in arid regions. With 69,836 rural residents currently lacking access to safe water, our results underscore the urgent need for infrastructure investment to meet SDG 6 targets (ensure availability and sustainable management of water and sanitation for all). Full article

The unique anticline geological structure in the central region of Yingjisha County results in significant spatial variations in groundwater quality. The study shows that the recoverable groundwater reserves account for 13.5% of the natural groundwater supply, and the development potential is considerable. Therefore, this study conducts an in-depth analysis of the spatial distribution characteristics of multiple water sources, integrates agricultural cropping patterns, and delineates irrigation districts accordingly. A water quality-based optimized allocation model for water resources is established. After optimization, the total irrigation water demand is reduced from 3685.8 million m³ to 3229.9 million m³, with total groundwater extraction controlled at 694.0 million m³. The total water shortage rate is 12%, and the decline in groundwater levels has been effectively controlled. Additionally, 116.4 million m³ of saline water is utilized, achieving an 83% utilization rate, which accounts for 16.8% of total groundwater extraction. Consequently, the utilization rate of freshwater decreases from 127% to 64%, while the overall water supply reliability reaches 87.6%. The sequence of water supply and consumption in the model remains consistent with the existing supply structure, demonstrating the rationality of the model parameter settings. This study proposes an optimal freshwater–saline water allocation model, which mixes saline water with reservoir water for dilution and subsequent agricultural irrigation. The approach aims to exploit the potential of saline groundwater and enhance the utilization efficiency of groundwater systems, thereby providing an innovative solution to alleviate water supply-demand conflicts in arid regions. Full article

Extreme climate events are increasing in severity and frequency and affecting the livelihood of pastoralists. Understanding these impacts is crucial for developing effective management strategies. Thus, this study examines the effects of drought on livestock production and market dynamics in semi-arid Ethiopia and explores the adaptation strategies employed by Borana pastoralists. Both the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were used to calculate indicators of drought severity between 1993 and 2022. Surveys were also conducted in 244 selected households. In addition, focus group discussions and field observations were conducted to investigate the adaptation practices of Borana pastoralists to drought. A line graph was used to illustrate the relationship between the Standardized Precipitation Index (SPI) and livestock market prices. The study found extreme drought in 1985, 2000, and 2011, with the most severe to moderate dryness occurring in the Arero, Elwaya, Dubuluk, Guchi, and Yabelo areas. The study found that severe droughts are increasing, affecting pastoralists’ livelihoods. The recurring drought led to a shortage of feed and water, which resulted in the starvation and death of livestock and jeopardized the livelihoods of pastoralists. In addition, the decline in milk production and falling market prices are said to have had a negative impact. Diversification of livelihood sources, mobility of livestock to seek out forage and water resources, and diversification of herd composition to take advantage of varying drought tolerance have been the usual long-term adaptation strategies of Borana pastoralists. Given the multiple negative impacts of climate change, development interventions in pastoral and agro-pastoral areas of Ethiopia should focus on proactive measures to reduce the impacts of climate change on livestock production. Full article

At the beginning of human history, surface water, especially from rivers and springs, was the most frequent water supply source. Groundwater was used in arid and semi-arid regions, e.g., eastern Crete (Greece). As the population increased, periodic water shortages occurred, which led to the development of sophisticated hydraulic structures for water transfer and for the collection and storage of rainwater, as seen, for example, in Early Minoan times (ca 3200–2100 BC). Water supply and urban planning had always been essentially related: the urban water supply systems that existed in Greece since the Bronze Age (ca 3200–1100 BC) were notably advanced, well organized, and operable. Water supply systems evolved considerably during the Classical and Hellenistic periods (ca 480–31 BC) and during the Roman period (ca 31 BC–480 AD). Also, early Indian society was an amazing vanguard of technology, planning, and vision, which significantly impacted India’s architectural and cultural heritage, thus laying the foundation for sustainable urban living and water resource management. In ancient Egypt, the main source of freshwater was the Nile River; Nile water was conveyed by open and closed canals to supply water to cities, temples, and fields. Underground stone-built aqueducts supplied Nile water to so-called Nile chambers in temples. The evolution of water supply and urban planning approaches from ancient simple systems to complex modern networks demonstrates the ingenuity and resilience of human communities. Many lessons can be learned from studying traditional water supply systems, which could be re-considered for today’s urban sustainable development. By digging into history, measures for overcoming modern problems can be found. Rainwater harvesting, establishing settlements in proximity of water sources to facilitate access to water, planning, and adequate drainage facilities were the characteristics of ancient civilizations since the ancient Egyptian, Minoan, Mohenjo-Daro, Mesopotamian, and Roman eras, which can still be adopted for sustainability. This paper presents significant lessons on water supply around the world from ancient times to the present. This diachronic survey attempts to provide hydro-technology governance for the present and future. Full article

In recent decades, societies and economies across the globe have started to show signs of stress associated with water shortages. Meeting the sustainability benchmarks in arid and semi-arid regions has caused water reuse to be considered a viable alternate source to augment the existing water supply resources. Water reuse, resource recovery, and recycling are extensions of the concept of a circular economy that has been practiced in other fields. Globally, the U.S. has played a leadership role in the development of guidance and regulations for various water reuse applications. Other countries and organizations have also developed similar programs. This paper aims to propose a review of the existing literature and provide a broader perspective of water reuse focusing on the most pressing issues such as direct potable reuse with the backdrop of viral pathogens and perfluorinated compounds. The global history of statutory developments to regulate the selected contaminants has also been discussed by covering the recent advancement in water reuse applications. Technological developments and regulatory trends are chronicled in the context of emerging contaminants linked with an imminent social, industrial, and agricultural prospectus. The proposed high viral log removal credit for water reuse is a challenging task especially at regular intervals; therefore, the treatment requirements must be verified to ensure public safety. The extreme persistence of PFAS, their tendency for buildup in biotic systems, and their removal is another challenging task which requires development of cost effective and efficient technologies. Disparity in the financial and technological capabilities of regional or internal stakeholders of shared watershed or aquifer is a bottleneck in tangible advancements in this area. The role of public–private partnerships in addressing the impending water sustainability challenges is discussed as a model for future direction in funding, managing, and public acceptance. Full article

Assessing water scarcity risks under climate change has become an important research topic for sustainable development. Regional water scarcity is driven not only by direct local water deficits but also by indirect effects from upstream supply chains. Despite their significance, existing studies seldom integrate both local water scarcity and indirect water scarcity comprehensively. This study utilizes multi-regional input–output tables (MRIO) to quantify virtual water flows among eight provinces in the Yellow River Basin, elucidating the extent of local (WSI) and indirect water scarcity (IWS) from 2007 to 2017. Leveraging Representative Concentration Pathway (RCP) projections and Shared Socioeconomic Pathway (SSP) scenarios, the research further projects future virtual water flow patterns and associated water scarcity risks in the Yellow River Basin from the 2020s to the 2090s. Findings reveal that downstream provinces (Shandong, Henan, Shanxi) experience more severe water scarcity—both locally and indirectly—than upstream regions (Inner Mongolia, Gansu). Local water scarcity surpasses indirect scarcity, with the agricultural sector predominantly driving IWS, accounting for 76.1% to 91.3%. Additionally, downstream provinces facing severe water scarcity not only exhibit high local water use but also rely on imports from middle and upper regions grappling with water shortages. Under SSP1-RCP2.6 and SSP5-RCP8.5 scenarios, water scarcity risks in the Yellow River Basin are projected to intensify, with the overall WSI potentially reaching 0.59 and IWS attaining severe levels of 0.42 by the 2050s. This study enhances the understanding of water scarcity risks in arid and semi-arid regions, providing valuable insights for policymakers to develop more climate-resilient water-resource management strategies. Full article