Search Results (2,610)

Numerical simulations quantify the transient impacts of implementing green infrastructure (GI) grass swales on unconfined aquifer storage and groundwater-surface water interactions around the Red Butte Creek (RBC) of Utah, USA. The Red Butte Creek Watershed (RBCW) transitions from undeveloped mountainous National Forest land to downstream urbanized areas within Salt Lake Valley (SLV). This reconnaissance-level study demonstrates that increasing stormwater infiltration in urbanized areas during the rainy months (April-June) can, until at least the subsequent March, (a) enhance aquifer recharge and support sustainable groundwater yields; and (b) improve surface water availability. Simulations predict hydrologic impacts of aquifer recharge resulting from hypothetical grass-swale implementation within a 704-acre area located around RBC. The employed model, HyperRBC, is an adaptation of a United States Geological Survey (USGS) transient numerical flow, MODFLOW, model implementation for SLV. Adaptations involved (a) uniformly refined horizontal discretization of seven aquifer layers within a sub-area encompassing parts of RBCW and an adjacent watershed; (b) updated input data; and (c) MODFLOW’s Streamflow-Routing (SFR) package to simulate RBC flow and aquifer-stream seepage. Model predictions indicated that by the end of next March: (a) about 3% of the GI-induced recharge would remain within the unconfined aquifer in the HyperRBC area; (b) 66.6% of the recharge would flow northward into the downgradient continuation of the unconfined aquifer; and (c) 30.3% would discharge to nearby stream and river. In summary, predicted hydrologic changes due to the short-term GI-induced recharge highlight increased groundwater availability within and outside the study area for at least the subsequent 12 months, including high-water-demand summer. These findings show the importance of GI in interim environmental management and in enhancing the effective use of water resources. Full article

Water-quality degradation in semi-arid basins is strongly influenced by spatial heterogeneity and cumulative anthropogenic pressure. This study characterises spatial gradients, identifies contamination hotspots, and evaluates system behaviour in the Jipijapa River micro-basin, Ecuador, through an integrated analytical framework. A multi-year dataset (2023–2025; n = 27) from nine monitoring sites was analysed using non-parametric statistics, regulatory exceedance-based hotspot detection, the BMWP/Col index, Spearman correlations adjusted by false discovery rate, and exploratory machine-learning models (Random Forest and ε-SVR) with leave-one-out cross-validation. Results showed a significant longitudinal gradient, with dissolved oxygen decreasing from 6.1 to 2.1 mg L⁻¹ and BOD₅ increasing from 6.1 to 111.0 mg L⁻¹ downstream. Five hotspots were identified, mainly in the lower reach, while BMWP/Col values declined from 118.3 to 37.0, indicating ecological degradation. Correlation analysis revealed strong coupling between BOD₅ and dissolved oxygen (ρ = −0.916), modulated by altitude and vegetation cover. Machine-learning models showed high internal consistency, although their use was restricted to diagnostic pattern detection rather than operational prediction. Overall, the convergence of physicochemical, ecological, hotspot, and modelling evidence supports an inferred spatial resilience gradient and provides a locally adaptable framework for prioritising watershed interventions in data-limited semi-arid basins. Full article

The evolution of groundwater in the Puhe River Basin is closely related to the ecological security of the Beijing–Tianjin–Hebei water source conservation zone. Based on 122 groundwater samples, this study systematically investigated the hydrochemical characteristics, evolution mechanisms, and water quality of shallow groundwater using mathematical statistics, Piper diagrams, ionic ratio analysis, and a variable fuzzy pattern recognition model. The results showed that shallow groundwater in the middle and upper reaches is generally weakly alkaline, fresh to hard water, with HCO₃–Ca and HCO₃·SO₄–Ca as the dominant hydrochemical facies. Groundwater hydrochemistry is primarily controlled by rock weathering, and the dissolution of silicate and carbonate rocks is the main source of major ions. Calcite and dolomite are in dynamic equilibrium between dissolution and precipitation, whereas gypsum and halite remain undersaturated. Overall, groundwater quality is generally good; however, anthropogenic activities in cultivated and construction lands have altered local hydrochemical composition and caused water quality deterioration in some areas. These findings improved the understanding of groundwater hydrochemical evolution in typical small watersheds of the northern Hebei hilly region and provided a scientific basis for the sustainable management and protection of groundwater resources in the Beijing–Tianjin–Hebei water source conservation area. Full article

Landscape pattern is closely associated with pollution in rapidly urbanizing watersheds, but most studies still focus on single pollutants or single environmental media. This study developed a watershed-based framework to compare coupled water and air pollution in the Liaohe River Basin, China. A total of 156 hydrologically connected sub-basins were used as common spatial units. Landscape metrics were calculated for 2000, 2010, and 2020. Total nitrogen and total phosphorus loads were simulated using the Soil and Water Assessment Tool, while annual mean PM_2.5 and O₃ concentrations were aggregated from gridded products to the same sub-basin scale. Coupling coordination degree was used to identify relative co-pollution patterns within the aquatic and atmospheric systems. GeoXGBoost with spatial block cross-validation was used to evaluate predictive performance, and GeoSHAP was used to interpret model-based predictor contributions. The aquatic coupled pollution index was predicted more accurately than the atmospheric index, indicating a stronger landscape association with nutrient coupling. Cropland proportion was the most stable predictor of aquatic coupling, whereas forest proportion was the most stable predictor of atmospheric coupling. These results suggest that water-oriented management should focus on cropland structure and ecological buffering, while air-oriented management should emphasize forest continuity and fragmentation control. The framework provides a spatially explicit basis for differentiated watershed management and territorial spatial planning. Full article

Change detection is a fundamental task in remote sensing with broad applications in urban monitoring, agriculture, watershed management, and land use and land cover analysis. In urban environments, accurate change detection is particularly critical for resource management, urban planning, and smart city development. Rapid urbanization has led to frequent and complex changes in buildings, which constitute key structural components of cities. Consequently, continuous and precise monitoring of building dynamics is essential for informed decision-making related to urban growth, environmental assessment, traffic management, and sustainable development. This paper presents a comprehensive review of two-dimensional (2D) and three-dimensional (3D) change detection methods applied to urban areas. Conventional and advanced approaches are systematically analyzed, and their strengths and limitations are critically discussed from a holistic perspective. Special emphasis is placed on recent learning-based techniques, which demonstrate enhanced robustness and accuracy in complex urban environments. Finally, current challenges and future research directions are identified to support the further development of effective 2D and 3D urban change detection methods. Full article

Massive nutrient inputs from different land uses have caused eutrophication in the Yangtze River. River sediment, as a sink for terrestrial nutrients, can sustain eutrophication for a long time. To further improve water quality, sediment organic carbon (TOC), nitrogen (TN), phosphorus (TP), and the impact of land use composition were investigated in the Tuojiang River watershed, once the most polluted tributary of the Upper Yangtze River. Results showed that the average TOC, TN, and TP contents were, respectively, 11.4 g/kg, 1078 mg/kg, and 1170 mg/kg higher than the local soil background value or the ecologically safe level limit. Due to the spatial layout of agriculture and industry, sediment nutrients were higher in the tributaries and the upper reaches of the main stream of the Tuojiang River. Regression analysis identified that TN was primarily affected by the composition of the dry-farm field within the 500 m zone along the river system, and TOC was affected by 1000 m of dry-farm field and 100 m of paddy field, while TP was related to the distribution of the phosphate chemical industry. It also enhances the urgency of reducing nutrient loss from agricultural non-point sources and mitigating residual nutrients in river sediment. Full article

Wetland system design, management and modelling to support ecosystem services during climate change have been evaluated in this structured and critical review. The focus was on non-tidal and agriculture-linked wetlands in oceanic, temperate and boreal regions. After applying 54 search terms using Google Scholar, 229 references have been cited. The review indicates that local wetland improvements rarely have a measurable impact on the overall watershed. Water can be retained mostly successfully in the landscape for relatively low- and medium-level rainfall. For large and less frequent floods, the concept of Retaining Water in the Landscape rarely applies. The success of compensation schemes for European and United States American farmers to control flood retention depends on financial status, farm size, age and the contract term duration. Ecosystem disservices such as greenhouse gas and nutrient release from ditches should be counteracted by rewetting. Combined water level and nutrient management supports carbon sequestration and protects watercourses from eutrophication. Restored wetlands usually reduce diffuse pollution and enhance biodiversity. The conservation of existing natural wetlands compared to restoring former wetlands is normally more effective regarding carbon storage. The value of sustainably managed wetlands is up to 50 times higher than the mean wetland restoration costs. Full article

Water balance calculations at the watershed scale are fundamental to water resource planning and the sustainable management of limited water supplies. These calculations rely on stream and canal gaging networks operated by local, state and federal entities, whose availability has varied over time due to cost, staffing constraints, and limitations on suitable gaging locations. The Green River Basin (GRB) above Fontenelle Dam in Wyoming illustrates this trend, where the number of operational stream gaging sites has varied over time and the majority of locations have less than 15 years of streamflow records. Recent advancements in the ability to perform streamflow reconstruction and estimate agricultural water use offer a new avenue for estimating the water balance for watersheds with discontinuous gage observations. But the use of these datasets and approaches has not been tested. Therefore, this paper proposes and tests a novel framework that combines discontinuous streamflow observations with new datasets (OpenET, ET-Demands, and GEOGLOWS) to calculate monthly water balances in the GRB from water year 1991 to 2023. Focusing on two main test basins, the Green River and the New Fork River, the integration of modern datasets enables the successful calculation of the water balance in the GRB with good agreement with downstream gaging records, achieving a Nash–Sutcliffe efficiency (NSE) of 0.88 for the New Fork River and 0.80 for the Green River. By improving the ability to quantify water balance components in data-limited basins, this framework supports more transparent water accounting and informed decision-making for sustainable water management, including irrigation planning, drought response, and long-term resource allocation in semi-arid river systems. Full article

Despite extensive research on soil organic carbon in karst regions, the synergistic changes in multiple carbon fractions and their stabilization mechanisms across a complete rocky desertification gradient remain poorly understood. To clarify how soil carbon pools and their drivers change during karst rocky desertification, we selected Kaiyuan City, Yunnan Province, China, as the study area. Total carbon (TC), soil organic carbon (SOC), and their related fractions, including particulate organic carbon (POC), mineral-associated organic carbon (MAOC), iron-bound organic carbon (Fe-OC), calcium-bound organic carbon (Ca-OC), and soil carbon isotopic composition (δ¹³C), were analyzed under different degrees of rocky desertification. SOC and TC followed a nonlinear pattern: increasing from no to potential desertification, decreasing at light and moderate stages, and rising again at the severe stage, indicating a phased response rather than a monotonic decline. POC was lowest under no rocky desertification and increased significantly after desertification occurred, reaching its maximum at the severe stage. MAOC peaked at the potential stage. With increasing rocky desertification severity, POC/SOC increased from no to moderate stages and then slightly decreased, whereas MAOC/SOC generally decreased. Fe-OC and Ca-OC were lowest under no desertification and increased after desertification occurred, pointing to enhanced mineral protection. Soil δ¹³C values under moderate and severe desertification were higher than under no, potential, and light desertification, implying intensified decomposition and a relative increase in C₄ plants. Mean weight diameter (MWD) and geometric mean diameter (GMD) did not differ significantly among rocky desertification stages (p > 0.05). In contrast, fractal dimension (FD) differed significantly only between the light and moderate stages (p < 0.05). Correlation and redundancy analyses showed that soil water content, bulk density, and porosity were the key factors driving variation in SOC and its fractions. These findings provide both a theoretical basis and practical guidance for soil restoration and ecological management in karst faulted basins affected by rocky desertification. Full article

The Beijiang River Basin is an important ecological security protection area and water source supply area in Guangdong Province. This study assesses the spatiotemporal distribution characteristics of watershed water quality based on on-site monitoring data and multivariate statistical analysis. The results indicate that PO₄³⁻P concentrations peak during the flood season, whereas pH, NO₃⁻-N, and total nitrogen (TN) reach their highest levels during the autumn normal-flow period. Spatially, water quality follows a gradient of upstream > downstream > midstream, with the midstream region identified as the primary zone of water quality degradation. Future non-point source (NPS) pollution characteristics in the Beijiang River Basin are influenced by land use/cover change (LUCC) and climate change, showing significant variation across Shared Socioeconomic Pathway (SSP) scenarios. Under SSP126, precipitation increases at the slowest rate, with a peak annual value of 1599.77 mm during 2031–2040 and an average basin temperature of 19.61 °C. In contrast, SSP245 exhibits a marked increase in precipitation, reaching 1802.92 mm by 2061–2070. Under SSP585, annual precipitation rises to 2200.04 mm, with temperatures approximately 0.5 °C higher than those under SSP126. Simulations based on the improved ESP-PLUS model indicate that, under the natural development scenario (NDS), expansion of construction land increases urban runoff pollution by 32.97%. Under the economic development scenario (EDS), 1023 km² of ecological land is lost, significantly weakening pollution interception capacity, while construction land increases by 26.01%. In contrast, the coordinated development scenario (CDS) reduces ecological land loss by more than 60% compared to EDS through balanced development and conservation, thereby maintaining the basin’s pollutant purification function. Overall, future nitrogen and phosphorus loads in the watershed are projected to first decrease and then increase. Accordingly, differentiated management strategies are recommended, emphasizing the coordinated development of economic growth and ecological protection, and providing a scientific basis for controlling NPS pollution under changing climatic conditions. Full article

The city of Bogotá is currently facing a water crisis marked by a worrying drop in the levels of the watershed subsystems that supply more than eight million people. This situation is exacerbated by population growth, climate change, deforestation, and poor water resource management. This research analyzes the current situation of water management in Bogotá based on hydrometeorological data, demographic forecasts, and surveys of citizen perception and adaptation to different measures, such as rationing. It highlights the high dependence on the spatial analysis highlights the high dependence on the areas primarily supplied by the Chingaza system presented higher vulnerability due to their dependence on a single supply source, as well as the evident impact of the El Niño phenomenon and the limited implementation of structural measures by the population. The results show that most people resort to immediate and cost-effective solutions, postponing the implementation of long-term sustainable strategies. Similarly, rationing affected different aspects of the daily routine of a large part of Bogotá’s population. Thus, this study highlights the need to strengthen water infrastructure, improve environmental education, and promote comprehensive public policies that ensure the sustainability of a resource as indispensable as water. Full article

As a critical decision–support tool for sustainable development in alpine lake watersheds, ecosystem service valuation requires scientifically robust accounting systems to inform environmental management. This study addresses the significant interference caused by multi-source heterogeneity in indicator selection, methodology application, and parameter determination within current valuation systems. We innovatively developed a multi-dimensional accounting framework. Through establishing standardized systems for indicators, methods, and parameters, taking Xingyun Lake as the research area, we systematically elucidated the differential impact mechanisms of accounting elements on valuation outcomes. Empirical results demonstrate that structural differences in indicator systems induce 11.61% of valuation fluctuations. Methodological choices lead to 13.86% of deviations. Insufficient parameter localization generates errors up to 18.48%. The refined framework improved valuation accuracy by 16.22%. This study quantitatively evaluates the influencing factors of ecosystem services and confirms a cascading amplification effect of element sensitivity (parameters > methods > indicators) on valuation outcomes, establishing methodological foundations for alpine lake watershed ecological accounting benchmarks. It has important decision-making reference value for applying ecosystem service function evaluation to sustainable development. Full article

Small hill reservoirs in arid North Africa face accelerating threats from soil erosion and siltation, yet integrated assessments linking erosion dynamics, water quality, and soil fertility remain scarce. This study presents a multi-component geospatial assessment of the 345 km² Es-Sabba watershed in the Saharan Atlas of southwestern Algeria. Soil loss was quantified using the revised universal soil loss equation (RUSLE) integrated with Sentinel-2 imagery, a 30 m digital elevation model (DEM), and GIS analysis for 2016–2025. The mean annual soil loss reached 26.3 t/ha/yr, with 68.4% of the watershed under high-to-severe erosion; topography and vegetation cover were the dominant controls. Estimated sediment delivery to the reservoir is 135,300 t/yr, projecting a functional lifespan of 11–15 years without intervention. Hydrochemical analysis classified reservoir water as alkaline- and sulfate-rich, yet suitable for irrigation with very low sodicity risk (sodium adsorption ratio, SAR = 0.08) and an excellent Irrigation Water Quality Index (IWQI = 91.75). Soils exhibited low-to-moderate fertility (mean soil fertility index, SFI = 0.416), with widespread nitrogen deficiency constraining vegetation-based erosion control. The integrated framework identifies circular-economy opportunities through nutrient-rich sediment reuse and provides actionable guidance for climate-resilient reservoir management in arid catchments. Full article

The Yangtze River Economic Belt supports over 400 million people and contributes nearly half of China’s GDP, yet decades of industrialization, urbanization, and agricultural intensification have resulted in severe contamination and pressing environmental challenges. This systematic review synthesizes three decades of peer-reviewed and governmental data to examine the spatiotemporal distribution, sources, and ecological and human health risks of major pollutants, including heavy metals, microplastics, persistent organic pollutants, and excess nutrients. While point-source emission of heavy metals such as cadmium, lead, and mercury have decreased by 35–42% since 2013 following policy interventions like the 10-Point Water Plan and the Yangtze River Protection Law, legacy contaminants in sediments and diffuse agricultural inputs continue to pose significant risks. Cadmium levels in rice still exceed food safety standards, arsenic in groundwater surpasses health guidelines, and microplastic flux into the East China Sea has reached 8.3 × 10¹² particles per year. Nutrient surpluses also drive extensive algal blooms, causing substantial economic losses. This review evaluates remediation strategies such as dredging, phytoremediation, wetland restoration, and AI-enhanced monitoring, which show removal efficiencies of 60–90% at reduced costs. However, critical gaps remain in understanding chronic mixture toxicity, the long-term fate of emerging contaminants, and pollutant–climate interactions. We propose an integrated basin-wide roadmap combining zero-liquid-discharge mandates, green infrastructure, and adaptive, performance-based governance to secure the Yangtze’s ecological and economic sustainability. This framework offers a transferable model for large-scale watershed management worldwide. Full article

Acid mine drainage is an important source of heavy metal contamination in mining watersheds, posing persistent risks to aquatic environments and sediment quality. This study evaluated heavy metal pollution in water and sediments of the acid mine drainage-impacted Xiaomi Creek watershed, China. A total of 20 water samples and 13 sediment samples were collected and analyzed for manganese (Mn), lead (Pb), copper (Cu), cadmium (Cd), aluminum (Al), nickel (Ni), iron (Fe), and zinc (Zn). Water pollution was assessed using the single-factor exceedance index and the Nemerow composite pollution index, whereas sediment contamination was evaluated using the geoaccumulation index and potential ecological risk index. The results showed that water in the Xiaomi Creek watershed spanned a broad pH range (3.16–8.05), and heavy metal pollution was generally more severe in the main channel than in the tributaries, indicating a clear influence of upstream pollution inputs. Nickel showed the strongest enrichment in sediments and posed the highest ecological risk among the investigated metals, while Mn, Pb, Zn, and Ni exhibited severe sediment contamination. Overall, upstream stone coal mining activities and associated waste piles were likely major contributors to heavy metal pollution in the watershed, highlighting the need for source control, sediment-associated risk management, and risk-prioritized monitoring to support sustainable watershed management. Full article