Search Results (10,177)

To quantify the spatial and lagged associations between ecological water conveyance and fractional vegetation cover (FVC) in Populus euphratica Oliv. forests, we integrated Landsat imagery (1995–2025), conveyance records, groundwater observations, and multi-period random forest classifications in the lower Tarim River. Newly formed or expanded surface water was mapped within dynamic annual response windows and characterized by annual surface inundation expansion area, multi-year inundation frequency, and distance from forest pixels to recurrently inundated water surfaces. These metrics were related to FVC using Theil–Sen trends and Lag 0–Lag 3 correlations. After 2010, reservoir releases, annual surface inundation expansion area, and groundwater conditions generally improved. Mean FVC increased by 0.182 percentage points per year, with improvement and degradation interspersed spatially. Relatively low- to moderate-frequency inundation was associated with pronounced positive FVC trends, and FVC improvement was concentrated within 0–0.5 km of recurrently inundated water surfaces. Associations of FVC with reservoir releases, groundwater depth, and annual surface inundation expansion area were strongest after 2–3 years. Together, these surface inundation metrics complement reservoir-release and groundwater records and support spatially differentiated monitoring of FVC changes in P. euphratica forests. Full article

Water depth substantially affects wave transformation over hybrid submerged breakwaters, yet the incremental effects of geotextile armoring and crest vegetation remain insufficiently understood. Experiments were conducted in the 50.0 m long, 0.8 m wide, and 1.2 m high wave flume at the Hydraulic and Harbor Engineering Laboratory of Tongji University. A hard submerged breakwater (HSB), a geotextile-armored submerged breakwater (GSB), and a vegetation-integrated ecological submerged breakwater (ESB) with identical core geometry were compared. Six irregular-wave conditions with H₀ = 0.06–0.16 m and T_p = 1.4–2.2 s were tested at h = 0.50 m, corresponding to an incident Ursell number range of U_ri = 2.97–27.26. Three still-water depths, h = 0.44, 0.50, and 0.56 m, were examined under H₀ = 0.12 m and T_p = 1.8 s, corresponding to a relative crest-submergence range of δ_c = $d_{\mathrm{c}}/\overline{H_{\mathrm{s},1}}$ = 0.33–1.38, where d_c is the still-water depth above the breakwater crest and $\overline{H_{\mathrm{s},1}}$ is the measured incident significant wave height at W1. Wave transformation, relative mean water-level adjustment, bulk wave coefficients, coefficient-based energy partition, wave spectra, and harmonic bicoherence were examined. With increasing U_ri, the energy partition shifts from transmission toward residual energy loss, while reflection remains secondary. Adding crest vegetation to the GSB reduces the transmitted energy fraction, T = K_t², where K_t is the wave-transmission coefficient defined as the ratio of transmitted to incident significant wave height, by an average of 5.2 percentage points over the tested U_ri range, whereas the tested partially exposed GSC armor alone produces no systematic attenuation improvement relative to the HSB. Increasing δ_c increases transmission while reducing reflection, residual energy loss, and relative mean water-level contrast. The incremental vegetation effect is non-monotonic and is greatest at d_c/l_v = 0.67, where d_c is the still-water depth above the breakwater crest and l_v is the upright vegetation blade length. Mean squared harmonic bicoherence, defined as the average squared bicoherence over the selected harmonic-coupling frequency-pair region, is consistently higher at the immediate lee-side gauge than at the seaward gauge, indicating enhanced coherent quadratic phase coupling among harmonic frequency components during wave transformation across the breakwater; this lee-side coupling generally weakens with increasing δ_c. Overall, relative crest submergence governs not only bulk attenuation but also the associated mean water-level and nonlinear phase-coupling responses, while crest vegetation provides a more consistent attenuation benefit than the tested GSC armor alone. Full article

With limited freshwater resources and growing water demands, it is imperative to identify and monitor water needs. Agricultural irrigation is the world’s largest water user, comprising 45–90% of freshwater withdrawals. Identifying and tracking changes in irrigated land is necessary for sustainable water management and forecasting agricultural water needs and patterns; however, the low resolution of available remote sensing observations hinders field-scale analysis. Downscaling soil moisture observations has been offered as a solution to this problem. Our study compares the performance of five irrigation identification methods using a newly developed downscaled deep soil moisture extrapolation method used to estimate Soil Moisture Active Passive (SMAP) soil moisture (SM) at a spatial resolution of 400 m for 5 cm, 20 cm, and 50 cm depths. Using this data along with Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) precipitation and Landsat Normalized Difference Vegetation Index (NDVI), we evaluate these methods with respect to crop type, irrigation type, and observation depth on agricultural fields in Colorado using the irrigation maps provided by the Colorado Decision Support System from 2015 through 2024. With no crop/irrigation type–observation depth combination exceeding an F1 score of 0.149 or MCC value of 0.163, we find that none of the methods can accurately identify irrigated land regardless of crop type, irrigation type, and observation depth. Because these methods succeeded in earlier small-area studies, and because the classified maps resolved into large, spatially uniform blocks, we interpret this as a limitation specific to field-scale detection over large, heterogeneous regions rather than a defect in the dataset. These findings highlight a limitation of this downscaled SM dataset and raise the question of whether other downscaled soil moisture products share this limitation. Full article

Sichuan taimen (Hucho bleekeri Kimura 1934) has experienced severe loss of spawning habitat due to hydropower development, as reservoir impoundment has inundated and altered the hydraulic conditions of its original riverine habitats, substantially reducing suitable habitats for its survival and reproduction. Identifying alternative spawning sites and creating suitable hydraulic conditions are therefore critical for this endangered species. Field investigations and literature synthesis identified key spawning requirements, including water velocity of 0.4–0.8 m s⁻¹, water depth of 0.2–0.8 m, sand–gravel substrates with ≥60% sand and fine gravel, and water temperature of 4–10 °C. An integrated ecological engineering scheme combining gravel-bar construction, substrate reconstruction, hydraulic optimization, and nursery habitat enhancement was developed. A depth-averaged, 2-D, hydrodynamic–habitat model showed that restoration increased WUA during the spawning period from 5.2–6.5% to 39.5–47.6%, corresponding to a 70–287% increase, with WUA increasing to up to ~3.9 times the pre-restoration value. The results demonstrate that ecological engineering can effectively enhance spawning habitat under hydropower-regulated flows and provide a transferable framework for endemic rheophilic fishes in regulated alpine rivers. Full article

Hydrothermal aquifers are natural systems useful for understanding deep fluid–rock interaction processes and, in particular, the fate of strategic raw materials, such as Rare Earth Elements (REE). This study investigates the geochemical behavior of dissolved REEs in hydrothermal systems of western Sicily (Italy), a tectonically active area of the south Mediterranean. These waters are discharged at a wide range of temperatures (18 °C to 56.1 °C) and electrical conductivities (0.81 to 35.06 mS cm⁻¹). Three major hydrochemical groups were individuated in the Langelier–Ludwig diagram: Group I (chloride–sulfate alkaline waters, with a seawater-like composition), Group II (chloride–sulfate earth-alkaline waters), and Group III (bicarbonate earth-alkaline waters, governed by CO₂ circulation). Total dissolved REE concentrations variate in a two-order magnitude range, from 10.2 to 954 ng L⁻¹. Patterns of shale-normalized REE show a progressive enrichment from light (LREE) to heavy (HREE) REEs, together with persistent negative Ce (Ce/Ce^∗ = 0.16–0.88) and prominent positive Eu (Eu/Eu^∗ = 1.87–4.42) anomalies. A shallow oxidative scavenging of Ce onto iron oxyhydroxide surfaces (Ce³⁺ → Ce⁴⁺) is suggested by its negative anomaly. The strong positive Eu is attributed to the preferential leaching of Eu²⁺ from feldspars, occurring at high temperatures at depth, before the upwelling of hydrothermal fluids. The amplitude of the third (T3) and fourth (T4) lanthanide tetrad effects was used for reconstructing the non-CHARAC (Charge And Radius Controlled) fractionation pathways, isolating distinct trajectories: Group I and II fluids are characterized by combined tetrad amplitudes, driven by the competitive complexation between un-fractionated deep sulfate/halide species and shallow, highly fractionating carbonate ligands. Furthermore, the middle-REE (δMREE) enrichment highlights interactions with fluids circulating in evaporitic deposits, and iron reductive dissolution by deep gas forcing. This comprehensive REE behavior is a useful geochemical tool for the characterization of the low-to-medium enthalpy geothermal systems in the south Mediterranean structural domain. Full article

In the northwest region of China, collapsible loess is widely distributed, and its special geological characteristics have brought numerous challenges to the construction of foundation engineering. As a new type of foundation form, the research on long and short pile foundations in the collapsible loess area of the northwest is still in the initial and exploratory stage. In-depth exploration of the bearing characteristics of long and short pile foundations in the loess area under the water immersion state is of crucial significance for the safety and stability of engineering construction in this area. This paper adopts the effective stress method, fully considers the important factor of pore water pressure, and combines it with the load transfer method to construct a calculation method for negative skin friction of long and short pile foundations in the collapsible loess area. Through theoretical derivation and analysis, it can be known that the calculation method established has many unique features. It explicitly defines the soil surrounding the pile as unsaturated soil, on the basis of which the effective stress method and the load transfer method are organically integrated, and then a segmented curve model for calculating the negative skin friction of long and short piles under the water immersion state was established. The advantage of this model lies in its comprehensive and in-depth consideration of the influence of multiple factors (including pore water pressure, effective stress, and pile-soil relative displacement) on the mobilization of skin friction. To further verify the accuracy and reliability of this calculation method, the indoor model tests were conducted: the axial force, the lateral friction resistance, and the vertical displacement of pile foundation were compared. The results show that there is a good agreement between the theoretical and experimental results, proving that the calculation method proposed in this paper is reasonable and feasible. The achievement of this research result can provide a valuable reference basis for the pile foundation design work in similar collapsible loess areas, help improve the quality and safety of foundation engineering construction in these areas, and promote the further development and progress of engineering technology in related fields. Full article

Deep lacustrine–fluvial soft ground at the Songyanghu Terminal (Phase III), Yueyang Chenglingji Port, was treated using vacuum wellpoint dewatering combined with dynamic compaction. A two-dimensional coupled solid-mechanics-Darcy model in coupled COMSOL Multiphysics 6.3 model was used to examine deformation and excess pore-water-pressure response, while an archived 360-day settlement series was used to evaluate three empirical prediction methods. The field dataset contains 12 settlement observations at a constant 30-day interval from Day 30 to Day 360. The numerical outputs indicate surface settlement approaching approximately 100 mm by Day 100; at Day 10, localised excess pore-water pressure remained at roughly 100 kPa near the mid-depth drainage zone, while most of the model domain was substantially lower. To avoid treating the same observations as both fitting and validation data, the Asaoka, hyperbolic and exponential methods were recalibrated using data ending at Days 180, 240 and 300 and then evaluated against the subsequent withheld observations. Across these three windows, the mean RMSE values were 0.02, 0.59 and 0.19 mm for the Asaoka, hyperbolic and exponential methods, respectively. The Day-360 measurement of 108.84 mm is therefore used as a reference observation rather than as a proven final settlement. For this single site and dataset, the Asaoka method produced the lowest numerical withheld-data errors; however, the differences between the Asaoka and exponential predictions are smaller than the stated ±1 mm levelling accuracy and therefore do not establish statistically or physically significant superiority. Broader applicability requires validation at additional sites and with independent monitoring datasets. These results provide a case-specific basis for post-construction settlement assessment of similarly treated soft ground. Full article

Climate change alters precipitation regimes, affecting flood hazard and sustainable urban development. This study assesses flood exposure of planned development and emergency assembly areas in Bismil and Çınar, Diyarbakır, Turkey, for 2023–2048. Precipitation projections from HadGEM2-ES, MPI-ESM-MR, and GFDL-ESM2M in RCP4.5 and RCP8.5 were bias-corrected using Equidistant Quantile Mapping (EQM) to develop intensity–duration–frequency (IDF) curves. HEC-HMS generated 100-year design hydrographs, HEC-RAS 2D simulated flooding, and GIS-based overlay analyses quantified exposure. In Çınar, maximum water depths ranged from 2.64 to 4.22 m, and inundation areas from 0.300 to 0.383 km². In HadGEM2-ES RCP8.5, exposed planned development areas increased from a reference value of 0.117 to 0.128 km², while exposed emergency assembly areas increased from 0.033 to 0.035 km². In Bismil, maximum water depths ranged from 6.39 to 7.41 m, and inundation areas from 4.320 to 5.932 km²; no overlap occurred with the evaluated development or assembly areas under any scenario. However, this absence does not imply that other parts of Bismil face no flood hazard. These differences highlight the need for district-specific exposure assessments. The framework identifies exposed development and assembly areas, supporting climate-adaptive land-use planning and sustainable urban resilience. Full article

The optical response of skin tissue in the near-ultraviolet to short-wave infrared band (350–2350 nm) contains rich physiological information such as hemodynamics, hydration status, and lipid metabolism. However, due to limitations in detector technology, conventional spectroscopic systems often use a single type of detector: silicon-based CCD (effective wavelength ≤ 1100 nm) captures visible blood features but cannot cover the long-wave vibration bands of water/lipids, while InGaAs (effective wavelength ≥ 900 nm) is sensitive to long-wave water/lipid absorption but misses the strong blood absorption in the visible region. This spectral detector segmentation leads to a separation of blood features from tissue background signals. In addition, traditional single source-probe distance measurement only probes one depth and cannot observe tissue information at different depths by varying the source-probe distance. This study employs a dual-spectrometer splicing architecture to achieve seamless continuous spectral measurement across 350–2350 nm by amplitude registration and normalization in the overlapping region. Using the thumb, palm, and arm as representative sites, we systematically analyzed spectral differences under varying vascular densities and fat backgrounds and successfully extracted absorption features of major chromophores including blood, water, and lipids. The results showed that the dual-spectrometer splicing method achieved smooth transitions in the overlapping region across different sites, validating its reliability. Spectral differences across sites were mainly characterized by hemoglobin absorption features in the visible region and water/lipid vibrational absorption features in the short-wave infrared region. These findings demonstrate the feasibility of dual-spectrometer splicing for broadband tissue spectral acquisition, enabling simultaneous capture of multi-component signals, and providing a new technical approach for non-invasive tissue composition analysis. Full article

Long-term morphodynamic responses to large ports are difficult to quantify when historical observations cover different periods, spatial domains, and engineering interventions. At Ashdod Port, on the Mediterranean coast of southern Israel, previous studies documented individual stages of coastal change, but the cumulative response to six decades of port development remained unresolved. This study reconstructs the Ashdod coastal system from 1957 to 2025 using historical and modern bathymetric–topographic surveys, shoreline analysis, and intervention-adjusted sediment balances. During 1965–1995, approximately 4.50 × 10⁶ m³ of sand accumulated within the ~2.5 km sector immediately south of the main breakwater (MBW), while a comparable deficit developed north of the port. Following construction of Ashdod Marina (1995–1997), accumulation became distributed across the southern sectors, while erosion persisted north of the port and extended farther downdrift. For 1965–2021, intervention-adjusted balances were +7.859 × 10⁶ m³ south and −7.208 × 10⁶ m³ north of the port, corresponding to +140 and −129 × 10³ m³/yr, respectively. Their similar magnitude and opposite signs constrain the long-term morphological response to interruption of the predominantly northward sediment-transport system but do not constitute a direct LST estimate. Successive port expansions extended the MBW head from ~15 to ~25 m water depth, across most of the sandy inner-shelf domain extending to ~30 m. North of the port, substantial sediment losses were accompanied by limited shoreline retreat, showing that shoreline change alone underrepresents the submerged response. Despite artificial northward transfer of ~1.457 × 10⁶ m³ since 2000, the downdrift deficit persisted. Historical accumulation south of the port should therefore not be equated with a presently available sand reserve. The record demonstrates the value of multi-decadal volumetric analysis for resolving cumulative port impacts and supporting sediment management on engineered sandy coasts. Full article

Shoreline erosion is a stress to coastal communities, and this is particularly true under climate change and sea level rise conditions. Understanding the mechanisms controlling shoreline erosion and the ability for future projections are critical for mitigation and planning. A parameterization has been developed to model shoreline erosion based on wave power and shoreline characteristics. The present study couples the shoreline erosion model with the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) and the third-generation Wind Wave Model (WWMIII) and conducts a long-term (1991–2014) simulation constrained by observed long-term shoreline erosion rates. The model revealed that wind waves inside the Bay are mostly locally formed and influence from offshore wave propagation is limited. Shoreline erosion quantity is comparable to sediment loads from the watershed but composed of more coarse material like sand. Interannual variability of shoreline erosion from weather variation was up to 58 percent from 1991 through 2014. Shoreline erosion has a significant influence on sediment distribution away from riverine inputs, but estuarine turbidity maxima dominate the transitional zones between fresh and salt waters in the tributaries as well as in the main stem Bay. A sensitivity analysis run with 53 cm sea level rise resulted in a 28 percent increase in shoreline erosion due to increases in water depth and wave power. Full article

Winter food conditions can shape behavioral investment, yet measured food mass and short-term foraging behavior need not covary. We quantified the potentially available food dry mass (FD), foraging-attempt rate (FAR), and 15 min behavioral time allocation of wintering black-necked cranes (Grus nigricollis Przevalski, 1876) in five habitats across three sampling stages in Linzhou County, XiZang. Food was sampled in eight independent plots per stage × habitat combination, and 600 valid focal observations were analyzed under a working-independence assumption. Habitat, sampling stage, and their interaction were associated with both FD and FAR (all nominal p < 0.001 in the fixed-effects models). Unplowed farmland consistently had the highest FD and FAR, whereas riverbank and shallow-water areas generally had the lowest values. Foraging accounted for 59.2–75.3% of observed time. Because different plots and partly different valleys were sampled among stages, these stage-associated contrasts combine temporal and spatial variation. Plot-level FD–FAR relationships varied among habitats and stages, showing that measured dry mass and a 1 min behavioral rate were not interchangeable indicators of food accessibility, foraging success, or energetic payoff. Future work should revisit fixed plots, retain individual–flock–plot–session identifiers, and quantify food identity, burial depth, hydrological conditions, successful ingestion, and detection-corrected habitat use. Full article

Conventional petroleum-based plastic packaging is facing formidable challenges in terms of both environmental sustainability and precise quality regulation of food products, compelling the food packaging industry to pivot toward biodegradable, recyclable, and intelligent solutions. Hydrogels, characterized by their unique three-dimensional network architecture, high water content, and excellent biocompatibility, have emerged as promising candidates for constructing next-generation sustainable food-packaging systems. This review presents a structured critical overview of the recent progress in multifunctional hydrogels derived from natural and synthetic polymers for food packaging applications. We begin by summarizing the structural characteristics and functional attributes of various polymeric substrates from different sources. Subsequently, we place emphasis on elucidating the molecular design and microstructural engineering strategies that enable enhanced mechanical properties, confer antimicrobial and antioxidant activities, and impart pH/gas-responsive intelligent functionalities. Furthermore, the regulatory mechanisms of forming and processing technologies—including solution casting, electrospinning, and three-dimensional printing—on the structure and performance of hydrogel-based packaging materials are discussed in depth. Finally, in view of the key bottlenecks currently impeding the widespread adoption of hydrogel packaging materials, particularly regarding water resistance, scalable production, and cost control, we outline future directions toward multifunctional synergism and quantitatively evaluated life-cycle performance. This review aims to provide a systematic theoretical basis and technical reference for the rational design of high-performance, intelligent, and sustainable food packaging systems for the future. Full article

Velocity distributions in curved open-channel flows exhibit strong three-dimensionality and nonlinear behavior, posing challenges to both accurate prediction and physical interpretation. Using measured velocity data from nine discharge–water-depth combinations in a laboratory 180° open-channel bend, this study developed an integrated eXtreme Gradient Boosting (XGBoost)–SHapley Additive exPlanations (SHAP) framework, with multiple linear regression (MLR), random forest (RF), and a back-propagation neural network (BPNN) used for comparison. Leave-one-condition-out cross-validation was used to evaluate the predictive accuracy and stability of the four models. A stratified sampling strategy was then adopted to construct the training dataset, allowing information from all flow regimes to contribute to robust parameter calibration; the two data-partitioning strategies yielded broadly comparable predictive performance. Using models trained with stratified sampling, multidimensional model evaluation was further conducted using global statistical metrics, segment-wise predictive performance, held-out extreme-condition tests, and measured–predicted agreement, among other criteria, with XGBoost consistently showing the best performance. Multilevel SHAP analyses quantified global feature importance, pairwise interactions, streamwise variations in feature contributions, SHAP–PDP dependence relationships, and condition-specific attribution. The SHAP results indicate a two-level attribution structure in the model: hydraulic variables jointly define the global velocity baseline, and their contribution signs can switch between positive and negative. Spatial variables characterize cross-sectional velocity redistribution. Strong discharge–depth interaction is associated with width-to-depth-ratio-dependent adjustment of the bend flow field. The proposed framework establishes a complete experiment-driven prediction–mechanism interpretation workflow for sharply curved open-channel flow and provides new quantitative insight into model-represented multifactor hydrodynamic interactions in open-channel bends. Full article

Antecedent soil moisture determines how much storage remains in bioretention media before rainfall, but its relationship with runoff control is poorly quantified. Three wet seasons of monitoring were analyzed for two field-scale bioretention systems with contrasting media depths, runoff loading, and drainage boundaries. For each event, antecedent available storage was calculated from the initial soil moisture profile relative to field capacity and, separately, to the 95th percentile of peak water content at each depth. Event-activated storage was defined as the greatest synchronous increase in water stored across the monitored profile following rainfall onset. Both storage metrics were expressed as equivalent rainfall depths over the contributing roof area. Runoff volume reduction ranged from 62.3% to 100% in BR1 and from 43.3% to 100% in BR2. Median event-activated storage over the media area was 4.9 mm in BR1 and 19.1 mm in BR2. However, after conversion to the contributing roof area, median antecedent storage was larger in BR1 than in BR2 under both the field capacity reference (3.8 versus 0.6 mm) and the high water reference (11.0 versus 5.0 mm). Greater antecedent storage was associated with a lower probability of drainage activation in both systems and greater runoff volume reduction in BR1. In BR2, greater event-activated storage was associated with lower runoff volume reduction, indicating that stronger within-event media wetting did not necessarily correspond to greater facility-scale runoff retention. Dynamic storage should therefore be interpreted in relation to hydraulic loading, media configuration, and drainage pathways. Full article