Water Transfer Research Articles

Effect of runoff water supply on vegetation and soil response to increasing aridity in Mediterranean drylands

Drylands are characterised by spatially discontinuous vegetation coverage. Consequently, during most rainfalls, runoff is generated in open areas and redistributed to vegetation. This transfer of water and nutrients from source to sink areas has been identified as a key ecohydrological process modulating drylands functioning. However, there are only a few experimental studies assessing the role of runoff redistribution on vegetation, and none of them evaluate its effect on determining the response of vegetation patches to aridification. In this study, we conducted a 3-year runoff exclusion experiment on 8 study sites consisting of Macrochloa tenacissima steppes distributed along two aridity gradients with contrasting lithologies in SE Spain. The aim was to assess the effect of runoff redistribution on vegetation and underlying soil communities as aridity increases, and to determine the influence of lithology on this response. For that, we compared a set of plants (photosynthetic activity, leaf chlorophyll content and green biomass production) and soil (microbial activity and composition) traits measured during different field campaigns on plants receiving run-on with the same variables measured on plants where run-on was excluded. Our findings demonstrate that run-on increases plant green biomass during wet periods with control plants showing a gain of the green biomass fraction higher than run-on excluded plants (difference between control and excluded plants is about ∼10 % of the total AGB in both gradients). By altering green biomass accumulation, run-on exclusion also shapes soil microbial communities (∼20 % of the aridity dependent ASVs are affected by run-on exclusion) and ameliorates the negative effects of drought on the activity and biomass of soil microorganisms (the decrease of SIR values between time 1 and 2 is 17 % lower in control than on run-on excluded plants), but it does not affect photosynthetic rate and chlorophyll concentration. This is due to the poikilohydric behaviour of M. tenacissima and the contrasting timing in the response of the measured variables to water pulses. Vegetation photosynthetic rates respond to short-term water availability, while green biomass and its indirect effect on the soil microbial communities results from a delayed response to the different rainfalls during the growing season. The effects of run-on were lower than expected and did not vary along aridity gradients, probably due to the unusual drought conditions and the atypical rainfalls during the studied period. During the last years, only a few large rainfalls were registered, causing soil moisture saturation under both excluded and control plants. Under these conditions, resources provided by runoff to control plants is diminished, thus lessening their competitive position compared to excluded plots. Long-term monitoring is necessary to evaluate the response of vegetation and the underlying soil to resource supply through runoff water with increasing aridity.

Modelling soil - Vegetation - Atmospheric interactions of radon products in a Belgian Scots pine forest site.

A soil-vegetation-atmospheric transfer (SVAT) model for radon and its progeny is presented to improve process-level understanding of the role of forests in taking-up radionuclides from soil radon outgassing. A dynamic system of differential equations couples soil, tree (Scots pine) and atmospheric processes, treating the trees as sources, sinks and conduits between the atmosphere and the soil. The model's compartments include a dual-layer soil column undergoing hydrological and solute transport, the tree system (comprising roots, wood, litter, and foliage) and the atmosphere, with physical processes governing the transfers of water and radon products between these compartments. A dose post-processor calculates dose rates to the trees from internal, external, and surface radiation exposures. The model parameterisation is based on measurement data from the Grote Nete Valley in the Belgian Campine region. The model results suggest that the tree intake of radon progeny is principally from the atmosphere, whereas radium is mainly taken-up from soil by the root uptake process, leading to an additional fraction of ingrown radon progeny in the tree by this route. It is also suggested that atmospheric uptake of radon is an essential mechanism when evaluating the tree uptake of 214Po, 214Pb and 218Po and subsequent decay products. The model also indicates a slow uptake of radionuclides by the tree roots, with timescales in the order of years, leading to different dose rates for young and mature trees. The importance of foliar surface deposition, leading to a dominance of surface doses to the tree needles, is also highlighted. These mechanisms, ignored in most assessment models, are necessary improvements for assessment tools dealing with the impact of radon and its progeny in forests, with regard to legacy sites with 226Ra contamination.

Modelling Water Management using SWAT+ : Application of Reservoirs Release Tables and the New Water Allocation Module in a Highly Managed River Basin

Abstract Incorporating the simulation of water management actions in hydrological models is paramount to enhance their reliability and usefulness. SWAT + (Soil and Water Assessment Tool) includes novelties in this aspect compared to its previous versions: the decision tables and the water allocation module provide enhanced capabilities for configuring management actions. Despite their potential, these features have not yet been applied due to their novelty. This study pioneers the use of SWAT + ’s new features applied in the Upper Tagus River Basin, a densely populated and highly regulated catchment. Irrigation, reservoir management, and various kinds of water transfers were incorporated in a SWAT + model of this basin. The implementation of management actions and their impact on the model performance were evaluated. The model accurately reproduced water demand for irrigation and water transfers, capturing both the demand volume and timing. The water sources were configured to meet most of the demand, with 73% of irrigation and 90% of water transfer requirements being satisfied. Release decision tables were configured for 31 reservoirs, resulting in an accurate simulation of outflow and storage in many of them. Incorporating management actions improved the streamflow simulation at the basin outlet, both considering the hydrograph and performance metrics (e.g., PBIAS was reduced by more than 50%). Some potential improvements in the model configuration and in the code were identified and will be addressed in future studies. This work provides a comprehensive guide to SWAT + ’s new features and the methodology employed, making it valuable for anyone working with the model.

Effect of the Shear Band on Water Migration in the Interface Between Lean Clay and an Engineering Structure: A Case Study of Loess-like Soil in Changchun Area, China

The entire deformation and overturning of numerous engineering structures commence from the failure of the interface between engineering structures and environmental soils, and the shear band formed by such failure results in variations in the water transfer law within the soil. In this study, a direct shear test was carried out to analyze the alterations in dry density of the soil both inside and outside the shear band before and after the disruption of the interface between lean clay and structure bodies, and the effect of the shear band on water migration in lean clay in the interface area under different shear displacements and normal stress values was examined. A numerical model of water transfer in lean clay with the shear band was constructed to predict the soil water distribution in the interfacial band across various temporal and spatial conditions. The results indicated that the existence of the shear band in the interface delayed the water migration; shear displacement and normal stress substantially affected the rate of water migration and volumetric water content in the interface region. The established water migration model could effectively simulate the migration patterns of water in the interface region and model the entire process of changes in free water in the soil under different spatial and temporal conditions. The research findings can provide a reference for the evaluation of structural permeability stability in hydraulic engineering.

Spatially explicit assessment of water stress and potential mitigating solutions in a large water-limited basin: the Yellow River basin in China

Abstract. Comprehensive assessment of the long-term evolution of water stress and its driving factors is essential for designing effective water resource management strategies. However, the roles of water withdrawal and water availability components in determining water stress and potential mitigating measures in large water-scarce basins are poorly understood. Here, an integrated analytical framework was applied to the Yellow River basin (YRB), where the water crisis has been a core issue for sustainable development. The analysis suggests that the YRB has experienced unfavorable changes in critical water stress indicators over the past 56 years. Compared to the period from 1965 to 1980, the regional water stress index (WSI) and the frequency and duration of water scarcity increased by 76 %, 100 %, and 92 %, respectively, over the most recent 2 decades. Water withdrawal was the primary driver of the increased WSI before 2000; however, it has since contributed as much as water availability. Meanwhile, local water management and climate change adaptation were shown to be important in determining total water availability at the sub-basin scale. Water demand in the 2030s is predicted to be 6.5 % higher than during 2001–2020 (34.2 km3) based on the trajectory of historical irrigation water use and corrected socio-economic data under different Shared Socioeconomic Pathways (SSPs). To meet all sectoral water needs, a surface water deficit of 8.36 km3 is projected. Potential improvements in irrigation efficiency could address 25 % of this deficit, thereby alleviating the pressure on external water transfer projects. Such efficiency gains would enable the WSI of the YRB in the 2030s to be maintained at the current level (0.95), which would worsen conditions for 44.9 % of the total population while easing them for 10.7 % compared to in the 2000s. Our results have vital implications for water resource management in basins facing similar water crises to that in the YRB.

Spatial and temporal distribution characteristics and source apportionment of biogenic elements using APCS-MLR model in the main inlet tributary of Danjiangkou Reservoir.

Danjiangkou Reservoir has been widely concerned as the water source of the world's longest cross basin water transfer project. Biogenic elements are the foundation of material circulation and key factors affecting water quality. However, there is no comprehensive study on the biogenic elements in tributaries of Danjiangkou Reservoir, hindering a detailed understanding of geochemical cycling characteristics of biogenic elements in this region. Guanshan River, one of the main tributaries that directly enter the Danjiangkou Reservoir, was token as the research object. Spatiotemporal distribution characteristics of basic water quality parameters and biogenic elements were studied. Water quality was comprehensively evaluated through water quality index (WQI). Absolute principal component score-multiple linear regression (APCS-MLR) model was adopted to explore the main sources of biogenic elements. Results showed that, in terms of season, the concentrations of total nitrogen (TN), total phosphorus (TP), and dissolved organic carbon (DOC) were significantly higher in wet season than in dry season, while no significant differences were found for dissolved inorganic carbon (DIC) and dissolved silica (DSi). Spatially, the concentrations of dissolved carbon, DIC, TN, and TP in the middle and lower reaches were higher than that in the upstream. DOC concentration peaked in the middle reaches, while DSi showed higher concentrations in the upstream. WQI values indicated that the river water quality was between good and excellent, although the water quality in wet season was slightly worse than that in the dry season. PCA extracted five potential sources, which accounting for 84.12% of the total variance, including rock weathering, mixed source of sewage discharge and agricultural non-point source pollution, dissolved soil CO2, seasonal factor, and agricultural non-point source pollution. These sources contributed 38.96%, 12.33%, 13.54%, 23.95%, and 11.21% to river water quality parameters, respectively. Strengthening the monitoring of biogenic elements, controlling pollutant discharge, and exploring the relationship between biogenic elements and other pollutants are important for the water environment management in this basin.

Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl2, CaCl2 and NH4Cl.

Electroosmosis reduces the available energy from ion transport arising due to concentration gradients across ion-exchange membranes. This work builds on previous efforts to describe the electroosmosis, the permselectivity and the apparent transport number of a membrane, and we show new measurements of concentration cells with the Selemion CMVN cation-exchange membrane and single-salt solutions of HCl, LiCl, NaCl, MgCl2, CaCl2 and NH4Cl. Ionic transport numbers and electroosmotic water transport relative to the membrane are efficiently obtained from a relatively new permselectivity analysis method. We find that the membrane can be described as perfectly selective towards the migration of the cation, and that Cl- does not contribute to the net electric current. For the investigated salts, we obtained water transference coefficients, tw, of 1.1 ± 0.8 for HCl, 9.2 ± 0.8 for LiCl, 4.9 ± 0.2 for NaCl, 3.7 ± 0.4 for KCl, 8.5 ± 0.5 for MgCl2, 6.2 ± 0.6 for CaCl2 and 3.8 ± 0.5 for NH4Cl. However, as the test compartment concentrations of LiCl, MgCl2 and CaCl2 increased past 3.5, 1.3 and 1.4 mol kg-1, respectively, the water transference coefficients appeared to decrease. The presented methods are generally useful for characterising concentration polarisation phenomena in electrochemistry, and may aid in the design of more efficient electrochemical cells.

Spatial and seasonal fish assemblage dynamics in a heavily urbanized estuary affected by interbasin water transference (Northeast, Brazil)

Spatial and seasonal fish assemblage dynamics in a heavily urbanized estuary affected by interbasin water transference (Northeast, Brazil)

Spatiotemporal Variation Assessment and Improved Prediction Of Cyanobacteria Blooms in Lakes Using Improved Machine Learning Model Based on Multivariate Data.

Cyanobacterial blooms in shallow lakes pose a significant threat to aquatic ecosystems and public health worldwide, highlighting the urgent need for advanced predictive methodologies. As impounded lakes along the Eastern Route of the South-to-North Water Diversion Project, Lakes Hongze and Luoma play a key role in water resource management, making the prediction of cyanobacterial blooms in these lakes particularly important. To address this, satellite remote sensing data were utilized to analyze the spatiotemporal dynamics of cyanobacterial blooms in these lakes. Subsequently, a precise machine learning model, integrating the Projection Pursuit Model and Random Forest (PP-RF) algorithms, was developed to predict the extent of cyanobacterial blooms, considering a range of influencing factors, including physical, chemical, climatic, and hydrologic variables. The findings indicated pronounced seasonal fluctuations in cyanobacterial blooms, with higher levels in summer than in other seasons. Key determinants for cyanobacterial blooms prediction included solar radiation, temperature and total nitrogen for Lake Hongze, while for Lake Luoma, significant predictors were identified as temperature, water temperature, and solar radiation. Compared with traditional data preprocessing methods, PP-RF model has advantages in addressing multicollinearity. This study provides a feasible method for predicting cyanobacterial blooms in impounded lakes within inter-basin water transfer projects. By inputting region-specific data, this model could be applied broadly, contributing to against the adverse effects of cyanobacterial blooms and provide scientific guidance for the protection and management of aquatic ecosystems.

National-Scale Optimized Design of Cost-Effective Water Supply and Transfer Systems

National-Scale Optimized Design of Cost-Effective Water Supply and Transfer Systems

Integrated management of the raw water transfer invasion pathway

Integrated management of the raw water transfer invasion pathway

Potential Inter-basin Water Transfer from the Kelani River to Mahaweli River, Sri Lanka to Mitigate Water Issues

Potential Inter-basin Water Transfer from the Kelani River to Mahaweli River, Sri Lanka to Mitigate Water Issues

Roughness and Energy Losses Induced by Mussel Growth on the Walls of Hydraulic Structures and Application to a Water Transfer Project

Roughness and Energy Losses Induced by Mussel Growth on the Walls of Hydraulic Structures and Application to a Water Transfer Project

Numerical investigation on energetic and exergetic performance of triplex concentric tube heat exchanger using MXene nanofluids

This study examines the heat transfer and fluid flow parameters for pure water and water-based (0.1–2% v/v.) MXene and (1% v/v.) Al2O3 nanofluid as hot fluids in a triplex tube heat exchanger (TTHX). Using a counter-flow configuration of the TTHX system, the research investigated the effects of the Reynolds number and volume fraction of nanoparticles on effectiveness, hydrothermal exergy loss, and entropy generation analysis. In the TTHX intermediate tube, the mass flow rate ranged from 0.06 kg/s to 1.6 kg/s, and a temperature of 343 K was considered. The key findings indicate that the 1% v/v. MXene nanofluid enhances the heat transfer rate by 12.5% compared to the Al2O3 nanofluid and by 20% compared to pure water in the TTHX system. The MXene nanofluid had 14.28% higher friction factor than pure water and 3.26% higher than the Al2O3 nanofluid. Increase in Nusselt number as compared to pure water is found to be 5.53%, 7.36%, 10%, 12.65%, 15% and 16.36% for Al2O3 nf, 0.1% Mxene nf, 0.5% Mxene nf, 1% Mxene nf, 1.5% Mxene nf and 2% Mxene nf respectively, at Reynolds number of 6800. The performance evaluation criteria for MXene nanofluid are 21.73% higher than for Al2O3 nanofluid at a Re of 6800, with an internal annulus fluid velocity of 0.1 m/s, and a specific value of Re at 4400, 1% v/v. MXene nanofluid is 29.7% more effective than Al2O3 nanofluid. Therefore, compared to traditional fluids, MXene nanofluids can improve the performance of a TTHX system.

Sensitivity analysis of geometrical parameters of supercritical water in twisted spiral tubes

ABSTRACT The high thermal efficiency of supercritical water makes it a promising alternative to water cooled reactors. This study employs numerical analysis, utilizing the SST k-ω turbulence model, to investigate the heat transfer performance of supercritical water (SCW) in various tube configurations and fluid flow conditions across Reynolds numbers ranging from 8,000 to 20,000. This research examines how different geometrical parameters, such as the helical direction, number of lobes, and cross-sectional shape, impact the flow physics and heat transfer performance of different spiral tubes. The outcomes specify that increasing the lobed number in the tube improves the heat flux by about 5%–16%. Furthermore, introducing two direction changes in the twisted tube will cause a slight increase (about 20%) on heat transfer enhancement. Finally, the sensitivity analysis of heat flux and Nusselt number to each of the effective parameters in the heat transfer of supercritical water in twisted tubes has been accomplished and the Response Surface Method (RSM) utilizes the central composite design (face-centered) approach. According to the findings of these two studies, it has been established that the Reynolds number of the fluid flow is the most influential parameter in determining the extent of heat transfer. Specifically, it exerts an effectiveness of 26% and 76% on the Nusselt number and heat flux, respectively. Furthermore, the inscribed circle diameter of tube by 8% effectivity and minor axis length by 5% effectivity on heat flux are more effective than others.

Nutrient loading as a key cause of short- and long-term anthropogenic ecological degradation of the Salton Sea

The Salton Sea (SS), California’s largest inland lake at 816 square kilometers, formed in 1905 from a levee breach in an area historically characterized by natural wet-dry cycles as Lake Cahuilla. Despite more than a century of untreated agricultural drainage inputs, there has not been a systematic assessment of nutrient loading, cycling, and associated ecological impacts at this iconic waterbody. The lake is now experiencing unprecedented degradation, particularly following the 2003 Quantification Settlement Agreement—the largest agricultural-to-urban water transfer in the United States. Combined with high evaporation rates, reduced inflows have led to rapid lake shrinkage, with current maximum depths of only 10 m. Here we report distinct temporal and spatial patterns for nutrient dynamics at the SS for two decades spanning the period before and after major water transfer agreement. While external nutrient loading remains relatively consistent year-round, internal cycling varies seasonally. Winter exhibits high total phosphates and nitrate levels due to reduced primary productivity, with lower ammonium concentrations from increased oxygenation. Summer conditions shift to decreased phosphate and nitrate levels from enhanced primary production, sustained partly by internal phosphorus release from sediments during anoxic periods. Although N:P molar ratios can exceed 50:1 to 100:1 (far above the Redfield ratio of 16:1), phosphorus consistently remains at hypereutrophic levels (> 0.05 mg/L) challenging previous assumptions of phosphorus limitation. Post-2020 data show disrupted stratification patterns. Despite higher oxygen levels in bottom waters compared to 2004–2009, overall water column oxygenation has declined, reflecting altered hydrodynamics in the shallowing lake. These changes have intensified environmental challenges stemming from cultural eutrophication including harmful algal blooms, threatening both ecosystem and public health. Effective remediation will require significant reduction in external nutrient loading through constructed wetlands and/or treatment facilities at tributary mouths to reduce the lake’s overall nutrient inventory over time.

Advanced Bionic 3D Interfacial Solar Steam Generator With One-way Water Supply for Highly Efficient Desalination and Oil-Fouling Prevention.

Interfacial solar steam generation (ISSG) employed for seawater desalination and wastewater purification shows great promise to alleviate global freshwater scarcity. However, simultaneous optimization of water transfer direction in a cost-effective and reliable ISSG to balance thermal localization, salt accumulation, and resistance to oilfouling represents a rare feat. Herein, inspired by seabird beaks for unidirectional water transfer, eco-friendly and cost-effective plant extracts, sodium alginate, and tannic acid, are selected for crafting an innovative Sodium Alginate-Tannic Acid Hemispheric Evaporator (STHE). The STHE aligned with centripetally tapered channels ensures one-directional water flow and effectively inhibits downward heat transfer, thereby boosting energy efficiency. Additionally, the integration of one-way water supply in tapered channels with interfacial evaporation of STHE, mimicking plant transpiration, collaboratively facilitates upward water transfer for a reliable solar-driven water evaporation rate of ≈2.26 kg m-2 h-1 under one sun irradiation. Even in a brine of 15.0 wt % solution, no salt crystals are observed on the surface of STHE. Hemispheric structure and superhydrophilicity are conducive to oil repellence. This work provides pivotal inspiration for constructing next-generation solar generators of high-efficiency, salt-tolerance, and anti-oil-fouling.

Copolymerization of Poly (Triazine Imide) Single Crystal Nanoplates with Enhanced Charge Transfer for Efficient Photocatalytic Overall Water Splitting

AbstractSolar‐driven photocatalytic overall water splitting represents a sustainable strategy to produce green hydrogen using metal‐free polymeric carbon nitride. However, conventional thermal polymerization with a single precursor for the synthesis of poly (triazine imide) faces challenges such as slow deamination rates and mass transfer, resulting in the formation of undesired structural defects, which usually serve as charge recombination sites and decrease the photocatalytic performance. Herein, highly crystalline poly (triazine imide) by thermal copolymerization of binary precursors of melamine and cyanuric acid in the presence of molten salts is reported. The results reveal that melamine and cyanuric acid easily generate melam (intermediates of carbon nitride) and subsequently facilitate the polycondensation process. Solid characterizations revealed that crystalline poly (triazine imide) nanoplates with extended π‐conjugation degrees and reduced intensity of structural defects would be obtained, which largely promotes separation and migration of photogenerated carriers, and inhibits the undesirable charge recombination at the defect sites. Accordingly, after in situ photo‐deposition of CoOx and Pt/Cr2O3 as O2 and H2 evolution co‐catalysts, respectively, the optimized crystalline poly (triazine imide) nanoplates achieve an excellent solar‐to‐hydrogen conversion of 0.30% under simulated sunlight irradiation.

Polyvinylidene Fluoride Nanofiber Murray Membrane for Quick Oil Absorption

With the rapid advancement of global industrialization, there is an increasing year-on-year demand for oil in society. The occurrence of oil spills during the processes of development, refining, and transportation has become an urgent issue that needs to be addressed. Electrospun fiber separation using selective oil/water absorption represents a relatively new yet promising technology. However, despite the lipophilic nature of the membrane for oil absorption, the rate of oil absorption is slow. There are still challenges in meeting the needs of developing communities. The plant employs a strategy of multi-branching with narrowed pores, which serves to enhance the efficiency of water and nutrient transfer. Inspired by plant transpiration, we adjusted the parameters of electrospinning and constructed a PVDF biomimetic nanofiber membrane with gradually reduced pore size through a bottom-up layer-by-layer spinning strategy. This PVDF biomimetic nanofiber membrane conforms to Murray's law. The experimental results showed that the oil absorption of carbon tetrachloride by PVDF Murray membrane was 3.06 g/g. Significantly, the PVDF Murray membrane demonstrates rapid adsorption of the oil slick (0.3 mL, n-hexane) in just 13s, as compared to 24s without the Murray structure. Therefore, the one-step preparation of the PVDF Murray membrane indicates a promising potential for its future application as a sustainable and quick oil-absorbent membrane.

Direct Contact Membrane Distillation of Hydroponic Solutions for Recycling of Phosphate and Potassium

A critical issue facing extraterrestrial expansion has always been long-term life support capabilities. The large energy requirements to move even small amounts of material from Earth necessitate the ability to reuse and recycle as much as possible, particularly waste. The weight of food supplies eventually starts to limit the length of the expedition. Hydroponic growth systems offer the ability to grow plants, and with them, a miniature ecosystem. This offers the ability to repurpose both carbon dioxide and waste salts such as ammonia and other compounds, such as those found in urine. A major issue facing hydroponic systems is the need to provide a stable water-based nutrient stream. Direct contact membrane distillation (DCMD) was tested for viability as a method of re-concentrating and stabilizing the nutrient-rich water stream. Polytetrafluoroethylene (PTFE)- and polyvinylidene (PVDF)-based polymer hydrophobic membranes were used to separate solutes from water. The DCMD method was tested with the feed stream operating at temperatures of 50 °C, 65 °C, and 80 °C. The results were analyzed using UV-Visible spectroscopy to determine concentrations. The benefits and limitations of the PTFE and PVDF membranes in DCMD were compared. The larger-pore PTFE membranes concentrated solutions effectively at 80 °C, while the PVDF membranes removed more water at lower temperatures, but permitted detectable phosphate ion leakage. Adjusting temperature and flow rates can help maintain stable ion and water transfer, benefiting hydroponic systems in achieving reliable nutrient levels.