Search Results (299)

Olyokma Nature Reserve, where we conducted our research, is in Eastern Siberia in the middle taiga zone in an area characterized by continuous permafrost. This is the only protected area in the region with a complete reserve regime, where there is no human activity. Here, we studied 14 different types of water bodies located along the Olyokma River valley, 13 of which were studied for the first time. For some of the studied water bodies, a high content of biogenic elements was noted, which may be associated with the characteristics of permafrost water bodies, which are under nutrient release from permafrost thaw. The concentration of several biogenic elements, including ammonium, nitrates and phosphates, increases in the water of the lakes toward the bottom of the river valley. In the composition of various communities of these water bodies, including both planktonic and non-planktonic, we identified 246 species and varieties of microalgae. The abundance and biomass of phytoplankton, as well as the number of species, decreased down the river valley. At the same time, at the upper stations there were more diatoms; while at the stations down the valley, green algae came to the fore; and even lower down, cyanobacteria prevailed. At the lower stations, the indicators of microalgae development were minimal. In accordance with the bioindicative properties of microalgae, a decrease in the trophic status of water bodies was noted down the river valley, which, in our opinion, is a characteristic feature of the waters of an undisturbed catchment basin in the permafrost area. This indicates that the studied aquatic ecosystem changes within a set of environmental and biological indicators, that is, it exists in natural conditions for this catchment basin. Research on the territory of Olyokma Nature Reserve allowed us to obtain information on natural transformation and removal of nutrients in permafrost catchments, while excluding the likelihood of anthropogenic impact on these processes. Full article

Urban green development has become a crucial approach for balancing ecological conservation and socio-economic development. The digital economy (DE) and new-type urbanization (NTU), as technological and social systems, respectively, are both driving urban green development. In this context, furthering their synergistic effects could substantially improve urban sustainability outcomes. Grounded in sociotechnical systems theory, this study applied pooled and multi-period fuzzy-set qualitative comparative analysis (fsQCA) to analyze urban green development pathways in 79 Yellow River Basin cities (2020–2022). The pooled fsQCA indicates that urban green development is driven by synergistic interaction within the NTU-DE subsystem, especially industrial digitalization–spatial urbanization. The multi-period fsQCA further demonstrates that industrial digitization has always existed as a core condition, which means that it plays a more general role. In addition, the Yellow River Basin exhibits distinct regional variations in urban green development, where the downstream region is dominantly driven by DE and spatial urbanization, the upstream region by industrial digitization, and the midstream region demonstrates diversified pathways. This study enhances understanding of complex system interactions in urban green development and provides policy-relevant insights. For policy implementation, local governments should not only prioritize effective synergies between industrial digitization and spatial urbanization but also develop differentiated strategies for the DE and NTU subsystems based on local conditions. Full article

The Henan section of the Sha Ying River Basin, as the core agricultural area of the Central Plains Urban Agglomeration (CPUA), plays a significant role in promoting regional green and sustainable development through the coordinated management of water–energy–carbon (WEC). This study takes the Henan section of the Sha Ying River Basin as a case study to analyze the spatiotemporal evolution characteristics of the region from 2010 to 2022, establish an evaluation system to assess the level of coupled coordination development, and utilize the gray correlation model to identify key influencing factors. The results show a fluctuating downward trend in WEC consumption, with low coupling coordination transitioning from high coordination to moderate imbalance. Key factors influencing coupling coordination include water consumption per 10,000 CNY of GDP, agricultural industry structure, and year-end population. Spatial heterogeneity in WEC coupling coordination factors was observed across cities. This research provides a scientific basis for understanding ecosystem dynamics in agricultural cities and supports differentiated environmental policies for sustainable regional development. Full article

The Yellow River Basin in China is the region with the most severe agricultural non-point source pollution. The control of agricultural non-point source pollution is an important task for ecological protection and high-quality development in the Yellow River Basin at present and in the near future. This paper takes the eight provinces located along the Yellow River, except Sichuan, as the research object. This study estimates the total amount, intensity, and structure of agricultural non-point source pollution from 2014 to 2023 by adopting quantitative methods such as the pollutant discharge coefficient method, the equivalent pollution load method, and so on. The results reveal that the total amount of non-point source pollution of the Yellow River Basin has risen from approx. 4.94 million tons in 2014 to approx. 7.45 million tons in 2023. However, the growth rate has decelerated over the past five years, and the pollution intensity has decreased by 15~40% on average. The characteristics of agricultural non-point source pollution presents as follows: chemical oxygen demand (COD) emissions have become the most significant pollutant, accounting for 90% of the total pollution; livestock and poultry breeding has become the main source of pollution; and the key areas of pollution have shifted from the lower reaches to the middle and upper reaches, but the regional differences have been narrowing, as measured by the Gini coefficient. An analysis of the Kuznets curve indicates that most of the provinces in the Yellow River Basin still depend on an extensive growth model characterized by high input, high emission, and low output. Finally, this paper proposes a classified governance and measurement system for regions and sources, aiming to enhance the agricultural non-point source pollution prevention and control system. It also advocates for accelerating the green transformation of agricultural production in the Yellow River Basin to achieve the rapid decoupling of pollution emission from economic growth. Full article

Water scarcity in Southern Europe, driven by climate conditions and water-intensive land use, is promoting water reuse adoption. Water reuse regulations are emerging, but little is known about integrating spatial concerns into their contents. This study examines how spatial issues are addressed within water reuse regulations adopted by the European Union (EU), Portugal, and Spain. Through a comparative content analysis, this research explores the inclusion and distribution of key terms related to water drivers, spatial concepts, and land use types within key sections, preamble, objectives, permitting, risk assessment, monitoring, and governance. The findings show that Portugal and Spain exhibit poorer integration of water scarcity compared to the EU, and Portugal does not address it in its objectives. In contrast, broad spatial terms are more prominent in Portugal, while Spain emphasises conservation and environmental areas more. Spatial terms are distributed differently across sections, reflecting different regulatory approaches. Surprisingly, none of the regulations link to plans. They mention risk management plans and, occasionally, circular economy and river basin management plans. Agriculture and urban activities dominate, although Portugal emphasises industry and green areas. This study highlights the need for more spatially informed water reuse regulations. Full article

This study evaluates the feasibility of repurposing produced water—an abundant byproduct of hydrocarbon extraction—for green hydrogen production in Wyoming, USA. Analysis of geospatial distribution and production volumes reveals that there are over 1 billion barrels of produced water annually from key basins, with a general total of dissolved solids (TDS) ranging from 35,000 to 150,000 ppm, though Wyoming’s sources are often at the lower end of this spectrum. Optimal locations for hydrogen production hubs have been identified, particularly in high-yield areas like the Powder River Basin, where the top 2% of fields contribute over 80% of the state’s produced water. Detailed water-quality analysis indicates that virtually all of the examined sources exceed direct electrolyzer feed requirements (e.g., <2000 ppm TDS, <0.1 ppm Fe/Mn for target PEM systems), necessitating pre-treatment. A review of advanced treatment technologies highlights viable solutions, with estimated desalination and purification costs ranging from USD 0.11 to USD 1.01 per barrel, potentially constituting 2–6% of the levelized cost of hydrogen (LCOH). Furthermore, Wyoming’s substantial renewable-energy potential (3000–4000 GWh/year from wind and solar) could sustainably power electrolysis, theoretically yielding approximately 0.055–0.073 million metric tons (MMT) of green hydrogen annually (assuming 55 kWh/kg H₂), a volume constrained more by energy availability than water supply. A preliminary economic analysis underscores that, while water treatment (2–6% LCOH) and transportation (potentially > 10% LCOH) are notable, electricity pricing (50–70% LCOH) and electrolyzer CAPEX (20–40% LCOH) are dominant cost factors. While leveraging produced water could reduce freshwater consumption and enhance hydrogen production sustainability, further research is required to optimize treatment processes and assess economic viability under real-world conditions. This study emphasizes the need for integrated approaches combining water treatment, renewable energy, and policy incentives to advance a circular economy model for hydrogen production. Full article

Continuous use of agricultural chemicals and fertilizers, sporadic sewer overflow events, and an increase in urbanization have led to significant nutrient/pollutant loadings into the semi-arid Arroyo Colorado River basin, which is located in South Texas, U.S. Priority nutrients that require reduction include phosphorus and nitrogen and to mitigate issues of low dissolved oxygen, in some of its river segments. Consequently, the river’s potential to support aquatic life has been significantly reduced, thus highlighting the need for restoration. To achieve this restoration, a watershed protection plan was developed, comprising several preventive mitigation measures, including installing green infrastructure (GI) practices. However, for effective reduction of excessive nutrient loadings, there is a need to study the effects of different combinations of GI practices under current and future land use scenarios to guide decisions in implementing the cost-effective infrastructure while considering factors such as the existing drainage system, topography, land use, and streamflow. Therefore, this study coupled the Soil and Water Assessment Tool (SWAT) model with the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) model to determine the effects of different combinations of GI practices on the reduction of nitrogen and phosphorus under changing land use conditions in three selected Arroyo Colorado subwatersheds. Two land use maps from the U.S. Geological Survey (USGS) Forecasting Scenarios of land use (FORE-SCE) model for 2050, namely, A1B and B1, were implemented in the coupled SWAT-SUSTAIN model in this study, where the urban area is projected to increase by 6% and 4%, respectively, with respect to the 2018 land use scenario. As expected, runoff, phosphorus, and nitrogen slightly increased with imperviousness. The modeling results showed that implementing either vegetated swales or wet ponds reduces flow and nutrients to meet the Total Maximum Daily Loads (TMDLs) targets, which cost about USD 1.5 million under current land use (2018). Under the 2050 future projected land use changes (A1B scenario), the cost-effective GI practice was implemented in vegetated swales at USD 1.5 million. In contrast, bioretention cells occupied the least land area to achieve the TMDL targets at USD 2 million. Under the B1 scenario of 2050 projected land use, porous pavements were most cost effective at USD 1.5 million to meet the TMDL requirements. This research emphasizes the need for collaboration between stakeholders at the watershed and farm levels to achieve TMDL targets. This study informs decision-makers, city planners, watershed managers, and other stakeholders involved in restoration efforts in the Arroyo Colorado basin. Full article

Grounded in the theory of new economic geography, this research develops a comprehensive theoretical framework to examine the spatial interaction mechanisms between the Green Finance Index and carbon emissions. Employing a range of econometric techniques—including three-dimensional kernel density estimation, spatial quantile regression, bivariate spatial autocorrelation analysis, and the spatial linkage equation model—the dynamic evolution, spatial pattern shifts, and mutual influences of green finance and carbon emissions in the middle and lower reaches of the Yellow River from 2003 to 2022 are systematically assessed. The findings indicate that (1) both carbon emissions and the Green Finance Index have experienced a trajectory of continuous growth, phased decline, and structural optimization, accompanied by a gradual shift in the regional center of gravity from coastal economic zones towards resource-intensive and traditional industry-concentrated areas; (2) significant spatial clustering is evident for both green finance and carbon emissions, demonstrating a strong spatial correlation and regional synergy effects; (3) a persistent negative spatial correlation exists between green finance and carbon emissions; and (4) green finance exerts a stable negative spatial spillover effect on carbon emissions, suggesting that the influence of green finance extends beyond localities to adjacent regions through spatial externalities, manifesting pronounced spatial transmission and linkage characteristics. By unveiling the bidirectional spatial association between green finance and carbon emissions, this study highlights the pivotal role of green finance in driving regional low-carbon transitions. The results provide theoretical insights for optimizing green finance policies within the Yellow River Basin and offer valuable international references for similar regional low-carbon development initiatives. Full article

The present study focuses on the sources and spatial distribution of potentially toxic elements (PTEs) and organic pollutants in water, canal bed sediment, and soil in the Versiliana urban park, an inclusive green area near the coast in the densely populated Versilia Plain of Tuscany. Surface water and bed sediments from canals crossing the urban park were collected at 10 stations during four different surveys to account for hydrological seasonality. Groundwater was collected in a survey through 10 piezometers. Eleven shallow soil samples were also collected, with the aim of evaluating the potential release of pollutants. Groundwater ranged from Ca-HCO₃, to NaCl, CaCl₂, and Na-HCO₃ water types, indicating conservative mixing and cation exchange processes during seawater intrusion. Most waters from canals belonged to the Ca-HCO₃ hydrofacies; a salinization shift, due to hydraulic connection with saline groundwater and soil sea salt dissolution, is observed. The concentration of most PTEs in groundwater and canal water is below Italian regulatory thresholds, with the only exception being As, which exceeds the legal limit in some samples. In most sediments, Ni, Cr, Zn, and As exceed the threshold effect concentration, and in some cases, the probable effect concentration. Geogenic PTE sources are attributed to metalliferous mineralization that characterizes the upstream Versilia River basin catchment. However, local PTE inputs from vehicular emissions and local industrial activities have been highlighted. Arsenic in sediments originated from geogenic sources and from arsenical pesticides, as indicated by the analysis of organic compounds, highlighting the legacy of the use of organic pesticides that have settled in bed sediments, in particular malathion and metalaxyl. The arsenic risk-based screening level in soil is lower compared with the regulatory threshold and with the measured concentration. Full article

A total of 24 hydropower stations are planned for construction in the upper Yellow River, from the Longyangxia to the Qingtongxia section, with completion anticipated by 2050. These stations represent the densest and highest-capacity reservoirs in China and play a crucial role in the ecological preservation and water resource management of the Yellow River Basin. To assess the ecological impacts of reservoirs on the surrounding environment, we analyzed vegetation dynamics in 10 reservoir areas between 2000 and 2020 using the normalized difference vegetation index (NDVI), examined the relationship between vegetation and climatic elements using biased correlation, and quantified the impacts of climatic factors and reservoir construction on the riparian vegetation using a generalized linear model (GLM) and path analysis. The findings indicated that the rate of vegetation growth declined after reservoir construction, and the overall trend indicated greening. Climate change impacts on riparian vegetation showed significant spatial heterogeneity, and the GLM analysis identified reservoir construction as the primary contributor to riparian vegetation dynamics, with a contribution rate of >50%. Temperature and soil moisture were the main climatic factors influencing vegetation growth in the reservoir area, with a 10–20% contribution rate. Path analysis further verified that reservoir construction directly enhanced riparian vegetation growth (with an impact coefficient of 0.514) and indirectly affected vegetation by altering the microclimate. This study emphasizes the importance of reservoir construction in assessing the relationship between riparian vegetation and climatic factors and provides insights for improved ecological conservation and water resource management strategies. Full article

It is of great significance to optimize water resource management and promote sustainable development in the Tarim River Basin (TRB) by using the water footprint (WF) evaluation method to evaluate the water shortage of fruit trees in the TRB and analyse its water-saving potential. This study aimed to elucidate the WF spatial–temporal distribution characteristics of fruit trees in the water-limited TRB from 2000 to 2020 and evaluate their water-saving potential capability. The WF was calculated using a combination of irrigation technology simulation and water usage assessments for four different fruit trees (apple, pear, date, and walnut). The results indicate that the green WF (WF_green) initially increased and then decreased, reaching its lowest value of only 175.09 m³/t in 2020, and decreased by 22.71% from 2000 to 2020. WF_blue decreased by 47.13% over the same period. In 2020, the WF_blue of date and walnut accounted for a higher percentage of WF_blue. WF_blue significantly exceeded WF_green, indicating their high water consumption and the limited adoption of water-saving technologies in the study area. Due to the increase in fruit tree planting area and fertilization, WF_grey exhibited an overall upward trend. Meanwhile, the total WF (WF_total) indicated a general downward trend, though the walnut tree had the highest WF_total at 2.21 × 10⁵ m³/t, indicating the popularization of water-saving technology. The results show that, taking 2020 as the baseline, the WF_blue of the four fruit trees in the TRB was 2.64 × 10⁵ m³/t (accounting for 89.1%), total WF_blue decreased by 0.73 × 10⁵ m³/t (a decrease of 48.38%) after drip irrigation, and the water-saving potential in the five prefectures of the TRB was in the range of 38.55–56.18%. Therefore, the promotion of drip irrigation technology plays a key role in alleviating the water pressure of fruit trees and promoting the sustainable utilization of water resources in the TRB. Full article

The interplay between terrestrial water storage and vegetation dynamics in arid regions is critical for understanding ecohydrological responses to climate change and human activities. This study examines the coupling between total water storage anomaly (TWSA) and vegetation greenness changes in the Hexi Corridor, an arid region in northwestern China consisting of three inland river basins—Shule, Heihe, and Shiyang—from 2002 to 2022. Utilizing TWSA data from GRACE/GRACE-FO satellites and MODIS Enhanced Vegetation Index (EVI) data, we applied a trend analysis and partial correlation statistical techniques to assess spatiotemporal patterns and their drivers across varying aridity gradients and land cover types. The results reveal a significant decline in TWSA across the Hexi Corridor (−0.10 cm/year, p < 0.01), despite a modest increase in precipitation (1.69 mm/year, p = 0.114). The spatial analysis shows that TWSA deficits are most pronounced in the northern Shiyang Basin (−600 to −300 cm cumulative TWSA), while the southern Qilian Mountain regions exhibit accumulation (0 to 800 cm). Vegetation greening is strongest in irrigated croplands, particularly in arid and hyper-arid regions of the study area. The partial correlation analysis highlights distinct drivers: in the wetter semi-humid and semi-arid regions, precipitation plays a dominant role in driving TWSA trends. Such a rainfall dominance gives way to temperature- and human-dominated vegetation greening in the arid and hyper-arid regions. The decoupling of TWSA and precipitation highlights the importance of human irrigation activities and the warming-induced atmospheric water demand in co-driving the TWSA dynamics in arid regions. These findings suggest that while irrigation expansion cause satellite-observed greening, it exacerbates water stress through increased evapotranspiration and groundwater depletion, particularly in most water-limited arid zones. This study reveals the complex ecohydrological dynamics in drylands, emphasizing the need for a holistic view of dryland greening in the context of global warming, the escalating human demand of freshwater resources, and the efforts in achieving sustainable development. Full article

This study, guided by the concept hat “lucid waters and lush mountains are invaluable assets”, focuses on explicating the ecological vulnerability characteristics of the Nanpan and Beipan River Basins, a typical karst river basin in Guizhou Province. In this article, a value equivalent table was built to calculate the ecosystem service value (ESV) within the basin from 2000 to 2020. The patch landscape and urban simulation model (PLUS) was improved to forecast ecosystem changes under four scenarios in the future. The Getis-Ord Gi*statistic, a spatial analysis tool, was introduced to identify and interpret the spatial patterns of ESVs in the study area. The research indicates that: (1) from 2000 to 2020, the spatial pattern of ecosystem has significantly improved, and with a notable ESV increase in the Nanpan and Beipan River Basins, especially the fastest growth from 2005 to 2010. Forest and grassland ecosystems are the main contributors to ESV within the basin, and the spatial distribution of ESV shows a decreasing trend from southeast to northwest. (2) Under different scenarios, forest ecosystem still would have the highest contribution rate to update the ESV between 2010 and 2035. The ESV is the lowest under the cropland protection scenario, amounting to CNY 104.972 billion. Compared to other scenarios, the ESV is higher under the sustainable development scenario, reaching CNY 106.786 billion, and this scenario provides a more comprehensive and balanced perspective, relatively achieving a harmonious coexistence between humans and nature. (3) The hot spots of ESV are mainly concentrated in the southeast and along the riverbanks of the study area. Urban ecosystems are the cold spots of ESV, indicating that protecting the ecosystems along the riverbanks is crucial for ensuring the ecological security and sustainable development of karst mountainous river basins. In the future development of karst mountainous river basins, it is necessary to strengthen ecological restoration and governance, monitor soil erosion through remote sensing technology, optimize the layout of territorial space to implement the policy of green development, and promote the harmonious coexistence of humans and nature, ensuring the ecological security and sustainable development of the basins. Full article

As an important ecological barrier and economic belt in China, the sustainable development of the Yellow River Basin (YRB) is of great significance to national ecological security and regional economic balance. Based on the coupled and coordinated development analysis of the water–soil–energy–carbon (W-L-E-C) system in the provinces of the Yellow River Basin from 2002 to 2022, this study systematically analyzed the interaction relationship among the various factors through WLECNI index assessment, factor identification, and driving factor exploration. Thus, it fully reveals the spatiotemporal evolution law of regional coordinated development and its internal driving mechanism. It is found that the coordinated development of the W-L-E-C system in different provinces of the Yellow River Basin presents significant spatiotemporal differentiation, and its evolution process is influenced by multiple factors. It is found that the coordination of the YRB presents a significant spatial difference, and Inner Mongolia and Shaanxi, as high coordination areas, have achieved significant improvement in coordination, through ecological restoration and clean energy replacement, arable land intensification, and industrial water-saving technology, respectively. Shandong, Henan, and Shanxi in the middle coordination zone have made some achievements in industrial greening and water-saving technology promotion, but they are still restricted by industrial carbon emissions and land resource pressure. The Ningxia and Gansu regions with low coordination are slow to improve their coordination due to water resource overload and inefficient energy utilization. Barrier factor analysis shows that the water resources utilization rate (W4), impervious area (L4), energy consumption per unit GDP (E1), and carbon emissions from energy consumption (C3) are the core factors restricting coordination. Among them, the water quality compliance rate (W5) of Shanxi and Henan is very low, and the impervious area (L4) of Shandong is a prominent problem. The interaction analysis of the driving factors showed that there were significant interactions between water resource use and ecological protection (W-E), land resource and energy use (L-E), and carbon emissions and ecosystem (C-E). Inner Mongolia, Shaanxi, and Shandong achieved coordinated improvement through “scenic energy + ecological restoration”, cultivated land protection, and industrial greening. Shanxi, Henan, and Ningxia are constrained by the “W-L-E-C” complex obstacles. In the future, the Yellow River Basin should implement the following zoning control strategy: for the areas with high coordination, it should focus on consolidating the synergistic advantages of ecological protection and energy development; water-saving technology and energy consumption reduction measures should be promoted in the middle coordination area. In the low coordination area, efforts should be made to solve the problem of resource overload, and the current situation of low resource utilization efficiency should be improved by improving the utilization rate of recycled water and applying photovoltaic sand control technology. This differentiated governance plan will effectively enhance the level of coordinated development across the basin. The research results provide a decision-making framework of “zoning regulation, system optimization and dynamic monitoring” for the sustainable development of the YRB, and provide a scientific basis for achieving high-quality development of the basin. Full article

A SWAT (soil and water assessment tool) model was built to elucidate the spatiotemporal dynamic changes in blue/green water resources during 1980–2019 in the Hanjiang River Basin, China. Several scenarios were constructed to analyze the spatiotemporal differentiation between green and blue water resources in diverse climate and land utilization conditions. The results showed that (1) the mean blue water and green water resources were 392.24 and 410.48 mm/year; (2) the blue water resources showed a non-significant fluctuating decreasing trend, while the green water resources showed a non-significant increasing trend in volume; (3) the high-value areas of the blue water resources were concentrated in the western, northeastern, and southeastern parts of the Hanjiang River Basin, whereas the western region had more abundant green water resources; (4) compared with the effects of land use change, the climate factors contributed much more to variations in the blue/green water resources of the Hanjiang River Basin. Overall, the blue/green water resources in most areas of the Hanjiang River Basin had a downward trend during 1980–2019. The findings may offer theoretical support for the optimal allocation and management of water resources in the Hanjiang River Basin, China, under climate change. Full article