Human Water Use Research Articles

Uncertainty in model estimates of global groundwater depth

Abstract Knowing the depth at which groundwater can be found below the land surface is critical for understanding its potential accessibility by ecosystems and society. Uncertainty in global scale water table depth (WTD) limits our ability to assess groundwater’s role in a water cycle altered by changing climate, land cover, and human water use. Global groundwater models offer a top–down pathway to gain this knowledge, but their uncertainty is currently poorly quantified. Here, we investigate four global groundwater models and reveal steady-state WTD disagreements of more than 100 m for one-third of the global land area. We find that model estimates of land areas with shallow groundwater at <10 m depth vary from 10% to 71% (mean of 23%). This uncertainty directly translates into subsequent assessments, as land areas with potential groundwater accessibility for forests, population, and areas equipped for irrigation, differ substantially depending on the chosen model. We explore reasons for these differences and find that contrary to observations, 3 out of 4 models show deeper water tables in humid than in arid climates and greatly overestimate how strongly topographic slope controls WTD. These results highlight substantial uncertainty associated with any global-scale groundwater analysis, which should be considered and ultimately reduced.

Seasonal variability in the global relevance of mountains to satisfy lowland water demand

Abstract Mountain areas play a vital role in global water resources as they often generate disproportionally high runoff and seasonally delay runoff due to storage as snow and ice. Water originating from mountains is used to satisfy human water demand further downstream in the lowlands of the corresponding river basins. Although the relevance of mountains for water supply is widely acknowledged, our current quantitative knowledge of their relevance for human water use on a global scale remains limited to decadal averages. As both water demand and mountain water supply have a strong seasonality, it is crucial to assess the global relevance of mountain areas beyond the annual time scale. To this end, we examined the share of lowland surface water abstraction (LSWA) stemming from mountain runoff in all river basins larger than 10,000 km2 globally from 1990 to 2019, focusing on the intra-annual variability. We distinguished between essential runoff contributions from low and high mountains and potential mountain runoff contributions to LSWA. Essential mountain contributions are defined as the share of water abstractions in the lowlands that can solely be satisfied by mountain runoff, whereas potential mountain contributions are the share that can originate from the mountains but does not necessarily have to. Our results confirm a strong spatial heterogeneity in the contribution of mountain runoff to LSWA. Globally, 15% of annual LSWA can solely be satisfied by mountain runoff, with monthly variations between 9 and 23%, highlighting the strong seasonality in the reliance on mountain runoff for lowland water use. The share of potential mountain contributions is much higher (51% annually). Slightly less than half of the essential mountain contributions to LSWA are sourced from high mountains. This shows the disproportional relevance of these regions, constituting only around one-third of the total mountain area. Furthermore, our results show an increasing dependence of lowlands on mountain water contributions.

Using national hydrologic models to obtain regional climate change impacts on streamflow basins with unrepresented processes

Climate change is increasingly impacting water availability. National-scale hydrologic models simulate streamflow resulting from many important processes, but often without processes such as human water use and management activities. This work explores and tests methods to account for such omitted processes using one national-scale hydrologic model. Two bias correction methods, Flow Duration Curve (FDC) and Auto-Regressive Integrated Moving Average (ARIMA), are tested on streamflow simulated by the US Geological Survey National Hydrologic Model (NHM-PRMS), which omits irrigation pumping. A semi-arid agricultural case study is used. FDC and ARIMA perform better for correcting low and high flows, respectively. A hybrid method performs well at both low and high flows; typical Nash-Sutcliffe values increased from <-1.00 to about 0.75. Results suggest methods with which national-scale hydrologic models can be bias-corrected for omitted processes to improve regional streamflow estimates. Utility of these correction methods in simulation of future projections is discussed.

An Opportunity for Synergizing Desalination by Membrane Distillation Assisted Reverse-Electrodialysis for Water/Energy Recovery.

Industry, agriculture, and a growing population all have a major impact on the scarcity of clean-water. Desalinating or purifying contaminated water for human use is crucial. The combination of thermal membrane systems can outperform conventional desalination with the help of synergistic management of the water-energy nexus. High energy requirement for desalination is a key challenge for desalination cost and its commercial feasibility. The solution to these problems requires the intermarriage of multidisciplinary approaches such as electrochemistry, chemical, environmental, polymer, and materials science and engineering. The most feasible method for producing high-quality freshwater with a reduced carbon footprint is demanding incorporation of industrial low-grade heat with membrane distillation (MD). More precisely, by using a reverse electrodialysis (RED) setup that is integrated with MD, salinity gradient energy (SGE) may be extracted from highly salinized MD retentate. Integrating MD-RED can significantly increase energy productivity without raising costs. This review provides a comprehensive summary of the prospects, unresolved issues, and developments in this cutting-edge field. In addition, we summarize the distinct physicochemical characteristics of the membranes employed in MD and RED, together with the approaches for integrating them to facilitate effective water recovery and energy conversion from salt gradients and freshwater.

Refuge identification as a climate adaptation strategy to promote fish persistence during drought

AbstractClimate change is leading to global increases in extreme events, such as drought, that threaten the persistence of freshwater biodiversity. Identification and management of drought refuges, areas that promote resistance and resilience to drought, will be critical for preserving and recovering aquatic biodiversity in the face of climate change and increasing human water use. Although several reviews have addressed the effects of droughts and highlighted the role of refuges, a need remains on how to identify functional refuges that can be used in a drought management framework to support fish assemblages. We synthesize literature on drought refuges and propose a framework to identify and manage functional refuges that incorporate species physiological tolerances, behaviours and life‐history strategies. Stream pools, perennial reaches and off‐channel habitat were identified as important drought refuges for fish. The ability of refuges to improve species resistance and resilience to drought requires careful consideration of the biology of the target species and targeted management to promote persistence, quality and connectivity of refuges. Case studies illustrate that management of drought refuges can be challenging because of competing demands for water, incomplete knowledge of ecological requirements for target species and the increasing occurrence of multi‐year droughts. Climate adaptation is increasingly important, and drought refuges can increase fish resistance and resilience to climate‐related drought across the riverscape.

Molecular phylogenetic analyses reveal a radiation of freshwater Gammarus (Amphipoda: Gammaridae) in the northern Chihuahuan Desert

Abstract Isolation of desert springs often leads to the evolution of unique biodiversity. We investigated the taxonomy and evolutionary relationships of members of the Gammarus pecos complex, an assemblage of narrowly endemic amphipod species in the Chihuahuan Desert of the USA. Morphological and molecular phylogenetic analyses, including newly obtained COI sequences from the now-extinct type population of Gammarus desperatus, reveal the presence of two undescribed species and lead to redescription of G. desperatus. Gammarus acerbatus sp. nov. is split from G. desperatus and Gammarus balmorhea sp. nov. is split from G. hyalelloides. Each of these species is endemic to a single spring system. Speciation in the Gammarus pecos complex was likely promoted by the lineage’s ties to marine/riverine systems and geological events during the Oligocene/Miocene. The additional diversity discovered within the complex highlights the effects of both habitat and evolutionary history on the processes of speciation at local and regional spatial scales. The entire complex of at least six species is imperilled due to the narrow ranges occupied by each species and human water-use that threatens the existence of their spring habitats.

How climate change and groundwater extraction will shape the global terrestrial water cycle pattern

Human groundwater extraction alters hydrological processes, thereby influencing climate through land–atmosphere interactions. As socioeconomic development progresses, the escalating water demand exacerbates conflicts with limited water resources. Nevertheless, potential response of the global terrestrial water cycle to the combined impact of climate change and groundwater extraction under various future scenarios remain vaguely understood. Therefore, this study developed human water regulation projection schemes based on Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) integrated into a global climate model (CAS-FGOALS-g3). The results show that global water demand in 2100 under the SSP370 scenario almost doubled relative to 2010. The proportion of surface soil drying due to warming is 3%-11% more in the medium- and high-emission scenarios than in the low one. In major irrigated areas, excessive groundwater extraction changed the groundwater storage trend, especially in the Southern Plains of the United States, where the increasing groundwater storage trend became negative compared to scenarios without groundwater extraction. This study underscores the complex interplay between human water use and hydroclimate within an evolving environment, emphasizing the critical need for effective water resource management to mitigate future water stress.

Streamflow Intermittence in Europe: Estimating High‐Resolution Monthly Time Series by Downscaling of Simulated Runoff and Random Forest Modeling

AbstractKnowing where and when rivers cease to flow provides an important basis for evaluating riverine biodiversity, biogeochemistry and ecosystem services. We present a novel modeling approach to estimate monthly time series of streamflow intermittence at high spatial resolution at the continental scale. Streamflow intermittence is quantified at more than 1.5 million river reaches in Europe as the number of no‐flow days grouped into five classes (0, 1–5, 6–15, 16–29, 30–31 no‐flow days) for each month from 1981 to 2019. Daily time series of observed streamflow at 3706 gauging stations were used to train and validate a two‐step random forest modeling approach. Important predictors were derived from time series of monthly streamflow at 73 million 15 arc‐sec (∼500 m) grid cells that were computed by downscaling the 0.5 arc‐deg (∼55 km) output of the global hydrological model WaterGAP, which accounts for human water use. Of the observed perennial and non‐perennial station‐months, 97.8% and 86.4%, respectively, were correctly predicted. Interannual variations of the number of non‐perennial months at non‐perennial reaches were satisfactorily simulated, with a median Pearson correlation of 0.5. While the spatial prevalence of non‐perennial reaches is underestimated, the number of non‐perennial months is overestimated in dry regions of Europe where artificial storage abounds. Our model estimates that 3.8% of all European reach‐months and 17.2% of all reaches were non‐perennial during 1981–2019, predominantly with 30–31 no‐flow days. Although estimation uncertainty is high, our study provides, for the first time, information on the continent‐wide dynamics of non‐perennial rivers and streams.

Appraising the eco-health of Tigris River water using pollution indicators and the health risk assessment model

ABSTRACT The Tigris River is a major source for supplying water for various purposes (drinking, domestic, industrial, and agricultural) for many cities and villages, and evaluating its water for human use is an important goal. For assessment purposes, nine stations, nine elements, four eco-health pollution indicators, and a health risk assessment model were chosen to evaluate the Tigris River's water environmentally and healthily in three governorates, namely Nineveh, Salah Al-Din, and Baghdad, in April 2023. The results of pollution indicators like the heavy metal pollution index, metal index, synthetic pollution index, and Nemerow Index showed that the Al-Qayyarah and Baiji sites were distinguished by higher values compared to the other stations. High concentrations of cadmium and lead, above the permissible limits for drinking water according to the World Health Organization, have clearly affected the values of pollution indicators. This research showed that there are non-carcinogenic risks to children from drinking water in the Qayyarah and Baiji stations due to the hazard quotient exceeding 1, while there are no risks to adults. Regarding the use of Tigris River water for bathing purposes, the risk quotient value was ,1 for all study stations, indicating that there are no risks to children and adults.

Reframing water demand management: a new co-governance framework coupling supply-side and demand-side solutions toward sustainability

Abstract. Water demand management adopts economic and non-economic measures to reduce human water use. However, it is argued in this study that water use changes may cause idle water supply facilities and revenue losses, thereby challenging the sustainability of water supply systems in the context of climate change. A co-governance framework was established to inspire practical strategies of sustaining water supply systems by re-evaluating the long-term impacts of water demand changes. This framework adopts a broader view of water demand management by integrating the political, financial, and consumptive needs of the government, the market, and the users in the form of a collaborative strategy coupling both supply-side and demand-side solutions. The proposed framework was applied to the analysis of the sustainability of China's South-to-North Water Diversion Project. It is found that the South-to-North Water Diversion Project is not a simple water supply infrastructure but rather a synthesis of supply-side and demand-side water management solutions. Actively releasing water for ecological and cultural purposes is suggested in this study to maintain the socio-ecological benefits of the project in the context of human water use decline. The economic cost of the water supply could be recovered by ongoing revenues that include not only the water fees charged to users but also the benefits gained from cooperative investment in broader water-related businesses by both the state-owned water transfer company and local governments in water-receiving areas. The proposed framework and strategies are valuable for other water utilities around the world, especially those challenged by reduced water demand caused by climate change, high water prices, and economic depression.

Water scarcity assessment index from the realistic perspective of human basic water requirements

Significant population growth with rapid economic development have led to water scarcity problems around the world. Currently, most of the simple water scarcity assessment methods only refer to per capita water use, failing to take into account actual water availability and actual human domestic water use. Therefore, we have developed a simple and practical method to assess water scarcity, incorporating total water resources, water use efficiency, and the proportion of domestic water. In this approach, a new water scarcity index is employed to describe different levels of water scarcity using various thresholds based on the basic daily human water use per person. This may help to visualize the extent of water scarcity in a region while focusing on human interests. To illustrate this approach, we take China–the world's largest developing country–as an example, analysing its nationwide water scarcity in 2021 while validating it with the results of other scholars on China's water scarcity. The results show that our water scarcity assessment index is very accurate, revealing that in 2021, the disparity in water resources between the northern and southern regions of China remains substantial, with severe water scarcity still widely concentrated in northern China.

Legal terminology in environmental and land law: theoretical-legal analysis

The article examines the peculiarities of the formation of legal terminology in the field of environmental and land law and proves the feasibility of its improvement in connection with the adaptation of the norms of national law to the law of the European Union. The article states that today in Ukraine there is significant environmental pollution, climate change, land deterioration, which significantly worsened in connection with the military aggression of the Russian Federation and caused a particularly dangerous ecological situation in the country. The article proves that the implementation of the principles of the right of citizens to a safe environment, ensuring human safety, protection and rational use of land, forest, water and subsoil resources is not possible without a clear definition of legal prescriptions enshrined in the law. The article states that one of the important aspects of the language of law is legal terminology, which makes it possible to formulate the content of a legal document. The article defines the concepts of “terminology”, “terminology”, “legal terminology”. It is noted that it is not appropriate to equate the concepts of “terminology” and “terminological system”. It has been investigated that despite the presence of established terminology in environmental law, the presence of terms in need of improvement is observed in this field, namely: “ecological law” and “environmental law”. It has been proved that for the purpose of further codification of environmental law, it seems appropriate to use the term “environmental law” as an established term of EU legislation. It has been analyzed that today the language of the law in the field of land relations is gaining importance, which is due to the formation of the land market in Ukraine and the need to adapt the norms of land law to EU law. It is noted that in land law there is a problem of identifying the terms: “land”, “land plot”. It was noted that the legal terms related to the formation of the land market in Ukraine need improvement and detailing. It was concluded that legal terminology in the field of environmental and land law is one of the important aspects of the development of the language of law. The issue of improving legal terminology in the field of environmental and land law is one of the necessary steps that will contribute to the unification and harmonization of the legal norms of the specified fields in the context of adapting the norms of national law to EU law.

Spatio-temporal analysis of river flow master recession curve characteristics over Ardabil province rivers

The Master Recession Curve (MRC) is a crucial tool for evaluating, managing, and utilizing rivers, particularly under low-flow conditions. Analyzing changes in the MRC of river flow is useful for water resource planning, surface water utilization, and estimating and allocating environmental flow. This study utilized daily flow data from rivers in Ardabil province, Iran over a 48-year statistical period (1970–2015). The Visual Basic program was utilized to estimate the equations and coefficients of recession curves. The trends of the constant and slope coefficients of the MRC equations were determined using the Mann-Kendall test and linear regression. Higher constant coefficient values were attributed to main rivers with higher discharge (e.g., Borran, Mashiran, and Samian, having 17.98, 13.79, and 5.64 cms, respectively. The slope of the MRC in most of the rivers in the central part of the study area exhibited a decreasing trend (p-value<0.05), which attributed to climate change, alterations in precipitation patterns, reduced rainfall/snowmelt, and water abstraction leading to less water input during non-flood periods. Additionally, most rivers in different climatic regions and areas of the study region exhibited an increasing trend (p-value<0.05) in the MRC constants, indicating reduced groundwater recharge or increased groundwater abstraction, as a common issue in the Ardabil province. Moreover, human water use and reservoir regulation (Yamci, Sabalan, Saghezchi, Givi, and small regulating reservoirs) can influence river flow patterns during non-flood periods. The occurrence of droughts and intensified surface water use by farmers, as well as unauthorized extraction of water from wells, have exacerbated this trend.

Physico‐chemical and bacteriological study of ground water quality of Belpahar area, Odisha, India using artificial neural networks

AbstractThe major objective of this work is to determine the degree of contamination of ground water in the Belpahar area of Odisha, India, by calculating WQI, assessing the presence of toxic metals, studying bacteriological analysis, and ultimately predicting the suitability of ground water for human use. A machine learning approach, the ANN model, was used to compare the experimental values with the predicted value of water quality and predict the level of contamination in the future. The level of performance due to modelling was evaluated by applying numerous statistical indices. The whole area was divided into five zones, such as residential, tourist, industrial, village, and coal mining areas, and ten ground water samples were collected in each zone. The WQI of the tourist area is 76.017, the village area is 70.721, the industrial area is 122.423, the residential area is 74.880, and the coal mining area is 115.507, indicating the industrial area is extensively polluted because of the impact of extensive industrialization. From the analysis of metals, it was estimated that toxic metals like Cr6+ (VI), Se, Mn, Zn, and Cu are much higher than the permissible limit, particularly in mining and industrial areas. From bacteriological analysis, it was found that the number of viable E. coli bacteria is highest in the TRL colony, that is, 18.2 × 107, and lowest in village areas such as Sarbahal (17.9 × 107), Ujjalpur (15.5 × 107), and tourist, industrial, and coal mining areas because of fewer human activities. Hence, suitable management, viable remedial measures, and the distribution of ground water in the Belpahar area must be recommended.

Synthesis, characterization and application of steel waste-based iron oxide nanoparticles for removal of heavy metals from industrial wastewaters

Water treatment and reuse can avail more clean and safe water for human use. In this study, iron oxide waste powder generated from the steel pickling process was used to develop iron oxide nanoparticles (IONPs) using solution gelation synthesis process. The powder and developed IONPs were characterized by X-ray fluorescence and diffraction (XRF, XRD), scanning electron microscopy, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller (BET) analyses. Adsorption experiments were carried out on synthetic water with lead and chromium metal ions. The adsorption data were analysed with Langmuir and Freundlich models. Adsorption kinetics were also analysed with Pseudo-First-Order and Pseudo-Second-Order models using non-linear regression. The synthesized IONPs were porous with active surface functional groups of hydroxyl bonds, with BET specific surface area of 325.02 m2/g. XRD results confirmed the cubic spinel structure of IONPs with particle sizes of 20–30 nm. The nanoparticles at a dosage of 0.35 g in 10 mL for 50 min effectively removed Pb(II) and Cr(VI) metal ions up to 99.9% from both synthetic water and industrial wastewater. The adsorption capacity (qmax) of IONPs was found to be 417 and 326.80 for Pb(II) and Cr(VI) respectively. Freundlich isotherm model data fitted best for the removal of both metal ions. The regression values for kinetic models confirmed that pseudo-second-order best fit the adsorption of both Pb(II) and Cr(VI) confirming chemisorption processes. This study contributes to elucidating alternative application of pickling waste from the steel rolling mills for the benefit of heavy metal removal in industrial wastewater.

The effects of reservoir storage and water use on the upstream–downstream drought propagation

Temporal aspects (e.g., response time and propagation rate) of drought propagation have been explored extensively by many studies, yet much less is revealed about the spatial characteristics of drought propagation. In our case study region the Shaying River basin with two major reservoirs, the effects of reservoir storage and water use on drought propagation, especially the upstream–downstream drought propagation, are closely investigated. It is found that meteorological droughts propagate to reservoir droughts in the river basin with drought pooling and lengthening. How hydrological droughts propagate from upstream to downstream is closely related to drought severity. Mild and moderate upstream reservoir droughts usually did not propagate to the downstream reservoir, but severe upstream reservoir droughts could propagate to the downstream reservoirs with delayed occurrence, prolonged duration, and increased severity. Severe reservoir droughts could lead to severe streamflow droughts, even after the end of reservoir droughts as an aftermath. During the period of drought propagation from upstream to downstream, the downstreamness of stored volume (Dsv) typically keeps going down from above the downstreamness of storage capacity (Dsc) at the beginning of drought occurrence, indicating relatively more water is stored in the downstream reservoir, to below Dsc at the end of drought, indicating relatively more water stored in the upstream reservoir. Although the increase of water uses aggravated hydrological drought in the long-term, the typical exacerbating effect of water use on hydrological droughts is not observed during 2013–2018 because most human water use was industrial and domestic which was generally stable over time. In the 2013–2018 period, upstream reservoir’s drought was driven by inflow variability, while downstream reservoir's drought conditions were predominantly shaped by mainly the variation of the outflow from the upstream reservoir. These findings offer crucial implications for policymakers, aiding in the formulation of robust drought and water management strategies that consider upstream–downstream dynamics, providing essential insights for river-basin scale water resource management and drought mitigation.

Experimental investigations: Reinforced Concrete Beams Bending Strength with Brine Wastewater in Short Age

The scarcity of waste in some regions has led to the contemplation of other approaches to providing potable water for human use. In the present research, it is proposed that a portion of the brine wastewater be recycled for potable water purposes through its incorporation into concrete and reinforced concrete compositions. The researchers performed an extensive empirical investigation to examine the impact of incorporating brine wastewater into the concrete mixture on the shear strength, bending stress, and compressive strength of the material. A total of seventy-two beams, each measuring 500 mm in length, 100 mm in width, and 100 mm in depth, were observed. A total of twelve beams were designated as control specimens, while an additional sixty beams were subjected to immersion in brine wastewater at varying concentrations of 2.5, 5, 7.5, 10, and 15%. The beams were reinforced using two longitudinal steel bars with a diameter of 8 millimeters in the tension zone and 6 millimeters in the compression zone. The stirrups included in the study were also measured to have a diameter of 4 mm. The samples were examined at intervals of seven, fourteen, twenty-one, and twenty-eight days. Based on the findings of this study and other relevant studies, it was determined that the use of 10% fresh water as a substitute for brine wastewater yielded the most optimal outcomes. The results obtained after a duration of 28 days indicate a notable increase in both the compressive and bending strengths of the concrete samples, with improvements of around 22% and 2.6% seen in comparison to the reference specimens. The impact of brine wastewater on the corrosion of reinforcing steel in reinforced concrete was investigated. The empirical findings indicated that the introduction of brine wastewater at a concentration of 10% to the concrete constituents did not provide any discernible repercussions over a period of 65 days. Doi: 10.28991/CEJ-2024-010-01-010 Full Text: PDF

Evaluation of biosynthesized GO@CeO2 nanocomposites as a catalyst for UV-assisted degradation of organic dyes and phytotoxicity studies

The availability of clean water for human use is one of the world's most pressing problems, and scientists are working hard to find a solution. Water that has been treated using nanotechnology is free of harmful microbes and organic dyes, making it superior to older treatment techniques. This research investigated the effects of light on graphene oxide nanocomposites infused with biosynthesized CeO2 nanoparticles. Numerous techniques were applied to characterize the as-prepared nanocomposites, including HRTEM, FTIR, XRD, XPS, UV-Vis, and Raman spectroscopy. Adsorbing and photodegrading CV, MB, and AO from an aqueous solution was accomplished with the help of a GO@CeO2 nanocomposite. Adsorption and photodegradation of the GO@CeO2 nanocomposite occur significantly more rapidly and efficiently in the presence of visible light than in the absence of light. The GO@CeO2 compound was able to eliminate 85 % of CV, 91.81 % of MB, and 87 % of AO in under 90 min. Adsorption alone is ineffective against CV, MB, and AO, but photodegradation in visible light is superior. According to the results of a research study with fenugreek plants, the treated effluents do not have any phytotoxic effects. Degradation of organic dyes in industrial wastewater using the GO@CeO2 catalyst was proven to be an efficient and inexpensive method.

Monitoring Lake Level Changes in Bosten Lake from 2003-2021 based on Multi-source Satellite Altimetry Data

The investigation of freshwater lake water resource changes in arid regions is crucial for understanding the evolution of regional lake dynamics under climate change, given their value and limited availability. This study aims to overcome the limitations of traditional water level monitoring methods and address the practical need for monitoring water level changes in Lake Bosten, located in the arid and semi-arid regions of China. To this end, we employed ICESat, ICESat-2, and CryoSat-2 altimetry data, as well as Landsat 8-OLI optical remote sensing data, to obtain the water level information for Bosten Lake from 2003 to 2022. We analyzed the temporal variation of the lake level and discussed the response of the lake level to climate and human activities in the context of temperature, precipitation data, and human water use. The water level of Lake Bosten exhibited a decreasing and then increasing trend, with three rising and three falling intervals, respectively. The intra-year variation of the lake water level exhibited bimodal characteristics, and the fluctuation range of water level during abundant water periods was greater than that during dry periods. Finally, we correlated the extracted lake water level with the measured water level at the hydrological station and found a significant positive linear correlation between the observed water level of Bosten Lake based on satellite altimetry and the measured water level at the hydrological station, with an overall correlation coefficient of 0.896 and 0.934 (P &lt; 0.01), indicating high accuracy of the water level results obtained in this study. The dynamics of Lake Bosten are influenced by a combination of climate change, hydrological elements, and human activities, with a relatively weak relationship between climate change and lake volume and a strong influence of human activities. Multi-source altimetry satellites provide a powerful tool for monitoring lake water levels over a long time scale, which is critical for studying lake water level changes and their response to climate and the environment.

Genetic erosion in an endangered desert fish during a megadrought despite long-term supportive breeding.

Human water use combined with a recent megadrought have reduced river and stream flow through the southwest United States and led to periodic drying of formerly perennial river segments. Reductions in snowmelt runoff and increased extent of drying collectively threaten short-lived, obligate aquatic species, including the endangered Rio Grande silvery minnow (Hybognathus amarus). This species is subject to boom-and-bust population dynamics, under which large fluctuations in abundance are expected to lower estimates of effective population size and erode genetic diversity over time. Rates of diversity loss are also affected by additions of hatchery-origin fish used to supplement the wild population. We used demographic and genetic data from wild and hatchery individuals to examine the relationship of genetic diversity and effective population size to abundance over the last two decades. Genetic diversity was low during the early 2000s, but diversity and demographic metrics stabilized after the hatchery program was initiated and environmental conditions improved. Yet, from 2017 onward, allelic diversity declined (Cohen's d = 1.34) and remained low despite hatchery stocking and brief wild population recovery. Across the time series, single-sample estimates of effective population size based on linkage disequilibrium (LD Ne ) were positively associated (r = 0.53) with wild abundance and total abundance, but as the proportion of hatchery-origin spawners increased, LD Ne declined (r = -0.55). Megadrought limited wild spawner abundance and precluded refreshment of hatchery brood stocks with wild fish; hence, we predict a riverine population increasingly dominated by hatchery-origin individuals and accelerated loss of genetic diversity despite supplementation. We recommend an adaptive and accelerated management plan that integrates river flow management and hatchery operations to slow the pace of genetic diversity loss exacerbated by megadrought.