Search Results (216)

Malaria remains a major public health issue, especially near hydroelectric dams that often promote mosquito breeding. This study aimed to establish baseline epidemiological data during the construction of the Singrobo–Ahouaty dam to support assessment and decision-making for short- and long-term health impacts on surrounding communities. A cross-sectional survey was carried out in randomly selected households. Blood samples were analyzed using thick/thin smears and rapid diagnostic tests, while sociodemographic and behavioral data were collected via questionnaires. Statistical analyses included chi-square, Mann–Whitney, Kruskal–Wallis tests, and logistic regression. The malaria prevalence was 43.1% (394/915). The parasite density averaged 405.7 parasites/µL. School-age children (6–13 years) showed the highest prevalence (74.3%, p < 0.0001), while younger children (0–5 years) had the highest parasite density (1218.0 parasites/µL, p < 0.0001). Highly elevated infection rates (>51%) occurred in Sokrogbo, N’Dènou, and Amani-Menou, with the highest density in Ahérémou 1 (5663.9 parasites/µL). Risk factors included being an informal worker (ORa = 1.5), working in the raw material sector (ORa = 1.4) or market gardening/rice farming (ORa = 0.9; p = 0.043), and frequent mosquito bites (OR = 0.4; p = 0.017). These results underscore the need for stronger vector control strategies, improved bed net distribution and follow-up, and enhanced intersectoral collaboration in dam-influenced areas to reduce malaria transmission. Full article

With ongoing global warming, glacier lake outburst floods (GLOFs) and associated debris flows pose increasing threats to downstream communities and infrastructure. Glacial lakes differ in their triggering factors and breach mechanisms, necessitating event-specific analysis. This study investigates the GLOF risk of Jiongpuco Lake, located in the southeastern part of the Tibetan Plateau, using an integrated approach combining remote sensing, field surveys, and numerical modeling. Results show that the lake has expanded significantly—from 2.08 km² in 1990 to 5.43 km² in 2021—with the most rapid increase observed between 2015 and 2016. InSAR data and optical imagery indicate that surrounding moraine deposits remain generally stable. However, ice avalanches from the glacier terminus are identified as the primary trigger for lake outburst via wave-induced overtopping. Mechanical and geomorphological analyses suggest that the moraine dam is resistant to downcutting erosion, reinforcing overtopping as the dominant failure mode. To assess potential impacts, three numerical simulation scenarios were conducted based on different avalanche volumes. Under the extreme scenario involving a 5-million m³ ice avalanche, the modeled peak discharge at the dam site reaches approximately 19,000 m³/s. Despite the high flood magnitude, the broad and gently sloped downstream terrain facilitates rapid attenuation of flood peaks, resulting in limited impact on downstream settlements. These findings offer critical insights for GLOF hazard assessment, disaster preparedness, and risk mitigation under a changing climate. Full article

Geological surveys have vital importance at the planning stage of dammed reservoir construction projects. The results of these surveys determine the majority of the technical solutions adopted in the construction design to ensure the proper safety and stability parameters of the structure during water damming. Where the ground type is found to be different from what is expected, the construction project may be delayed or even cancelled. This study analyses issues and design modifications caused by the identification of different soil conditions during the construction of four new flood control reservoirs in the Nysa Kłodzka River basin in south-western Poland. The key findings are as follows: (1) a higher density of exploratory boreholes in areas with potentially fractured rock mass is essential for selecting the appropriate anti-filtration protection; (2) when deciding to apply deep piles, it is reasonable to verify, at the planning stage, whether they can be installed using the given technology directly at the planned site; (3) inaccurate identification of foundation soils under the dam body can lead to significant design modifications—in contrast, a denser borehole grid helps to determine the precise elevation of the base layer, which is essential for reliably estimating the volume of material required for the embankment; (4) in order to correctly assess the soil deposits located, for instance, in the reservoir basin area, it is more effective to use test excavations rather than relying solely on borehole-based investigations—as a last resort, test excavations can be used to supplement the latter. Full article

Suyukou Gully, located on the eastern slope of the Helan Mountains in northwest China, is a typical debris-flow-prone catchment characterized by a steep terrain, fractured bedrock, and abundant loose colluvial material. The area is subject to intense short-duration convective rainfall events, which often trigger destructive debris flows that threaten the Suyukou Scenic Area. To investigate the dynamics and risks associated with such events, this study employed the FLO-2D two-dimensional numerical model to simulate debris flow propagation, deposition, and hazard distribution under four rainfall return periods (10-, 20-, 50-, and 100-year scenarios). The modeling framework integrated high-resolution digital elevation data (original 5 m DEM resampled to 20 m grid), land-use classification, rainfall design intensities derived from regional storm atlases, and detailed field-based sediment characterization. Rheological and hydraulic parameters, including Manning’s roughness coefficient, yield stress, dynamic viscosity, and volume concentration, were calibrated using post-event geomorphic surveys and empirical formulations. The model was validated against field-observed deposition limits and flow depths, achieving a spatial accuracy within 350 m. Results show that the debris flow mobility and hazard intensity increased significantly with rainfall magnitude. Under the 100-year scenario, the peak discharge reached 1195.88 m³/s, with a maximum flow depth of 20.15 m and velocities exceeding 8.85 m·s⁻¹, while the runout distance surpassed 5.1 km. Hazard zoning based on the depth–velocity (H × V) product indicated that over 76% of the affected area falls within the high-hazard zone. A vulnerability assessment incorporated exposure factors such as tourism infrastructure and population density, and a matrix-based risk classification revealed that 2.4% of the area is classified as high-risk, while 74.3% lies within the moderate-risk category. This study also proposed mitigation strategies, including structural measures (e.g., check dams and channel straightening) and non-structural approaches (e.g., early warning systems and land-use regulation). Overall, the research demonstrates the effectiveness of physically based modeling combined with field observations and a GIS analysis in understanding debris flow hazards and supports informed risk management and disaster preparedness in mountainous tourist regions. Full article

To investigate the species composition, reproductive dynamics, and hydrological drivers of fish resources in the early stage in the Guiping section of the Xunjiang River, we conducted a two-year survey (2022–2023) downstream of the Datengxia Dam. A total of 22,464 fish eggs and larvae were collected, representing 6 orders, 17 families, and 67 species, with Cyprinidae (58.2%) as the dominant family. Dominant species included Squaliobarbus curriculus, Gobiidae, Hemiculter leucisculus, and Culter, exhibiting significant interannual variation in abundance. The breeding season peaked from May to September, accounting for 94.6% of annual recruitment. Hydrological conditions strongly influenced reproductive output: the multiple flood pulse periods in 2022 (peak discharge: 29,000 m³/s) yielded 34.997 billion eggs and larvae, whereas reduced flows in 2023 (peak discharge: 12,200 m³/s) led to a 75.4% decline (8.620 billion). Redundancy analysis (RDA) revealed that discharge, water temperature, natural hydrological data, and dissolved oxygen were the primary environmental drivers, explaining 46.11% of variability in larval abundance (p < 0.001). Notably, the proportion of important economic fish, “four major Chinese carps”, plummeted from 4.9% (2022) to less than 0.1% (2023), indicating spawning ground function degradation. Our results demonstrate that flood pulses are essential for sustaining fish recruitment, particularly for pelagic spawning riverine fish like the four major Chinese carps. Their proportion plummeted to less than 0.1% in 2023, highlighting the urgent need for eco-hydrological management in the Xunjiang River. Full article

Background and Objectives: The aim of this study was to evaluate how the indirect pulp capping treatment approaches and material choices used by dentists actively practicing in Turkey vary according to demographic data. Materials and Methods: Dentists practicing in Turkey were included in this study. A 13-question survey was used and distributed to the participants via social media. The statistical analysis of the data obtained from this study was performed using IBM SPSS v23. The chi-square test was used to compare categorical variables between groups, and multiple comparisons of the proportions were analyzed using the Bonferroni correction. The results of the analysis are presented as frequencies (percentages) for categorical data. The significance level was set at p < 0.05. Results: A total of 402 dentists from across Turkey participated in this study. A total of 331 participants (82.3%) reported that they performed indirect pulp capping treatment. The most commonly used materials for indirect pulp capping were Ca(OH)₂;-containing liners (73.4%) and glass ionomer cement (58.3%). The use of amalgam and cotton roll isolation was more common among dentists working in the public sector, whereas rubber dam isolation and the use of contemporary materials such as MTA and Biodentine were more frequently observed among dentists working in the private sector. Conclusions: Significant differences were found in the dentists’ indirect pulp capping approaches and the materials they used based on their specialty, years of experience, and workplace setting. These findings suggest that dentists’ knowledge and experience regarding indirect pulp capping should be enhanced during their education and post-graduation training. Full article

Climate change and extreme events such as droughts, heavy rainfall and flooding can influence the water column stratification in reservoir dams, decrease storage capacity, increase sediment and pollutant loads and, as a result, affect water quality. The seasonal variation in the water column stratification of reservoirs is an important parameter for the study of dam life cycle as well as water management and use. In the present study a detailed bathymetric survey was carried out, and a digital elevation model (DEM) of the reservoir was constructed. Seasonal physicochemical monitoring data such as temperature, dissolved oxygen, pH and conductivity are presented. The seasonal thermal stratification was recorded, resulting in an isolated hypolimnion where anoxic layers formed below 17 m in summer and autumn. Manganese and iron concentrations exhibited values higher than 150 mg/L in the anoxic hypolimnion during summer and autumn, indicating solubilization from the sediment. The observed seasonal and depth-dependent variations in physicochemical parameters underline the reservoir’s susceptibility to eutrophication and metal mobilization, particularly during stratified periods. These findings are critical for designing management strategies to mitigate potential water quality issues. Full article

The resettlement of development-induced migrants is a complex socioeconomic and cultural process. The levels of place identity among migrants may profoundly affect their long-term stability and sustainable development in host communities. For long-distance displaced migrants, their social relations undergo drastic changes, and the extent of social-relations reconstruction determines their place identity in the resettlement area. Previous studies mainly concentrated on migrant compensation schemes, housing, and land allocation, and livelihood restoration. However, insufficient attention has been paid to the mechanism by which social-relations reconstruction shapes place identity. Drawing on sample survey data collected during 2022–2023 from migrants displaced from the Three Gorges Dam (TGD) in China to various other provinces, this study conceptualizes place identity in three dimensions: group identity, permanent settlement intention, and expectations for children. A structural equation model (SEM) was employed to investigate how social relations, categorized as geographical, home-tied, and carried-over relations, mediate the influence of multiple factors on place identity. The findings are that: (1) among development-induced migrants, social relations exerted significant positive effects on place identity, along with personal characteristics, socioeconomic characteristics, land, and housing factors. Moreover, family features, socioeconomic characteristics, and land and housing factors all had a significantly positive impact on social relations; (2) social relations acted as a full mediator between family features and place identity, and a partial mediator between socioeconomic characteristics/land and housing factors and place identity; (3) among geographical, home-tied, and carried-over social relations, geographical social relations had the largest effect on place identity, followed by carried-over relations. However, continuous dependence on home-tied social relations negatively affected the migrants’ development of place identity in new resettlement areas. This study elucidates the role of social relations in the socioeconomic and cultural reconstruction during migrant resettlement, offering insight for improving resettlement policies and promoting sustainable community integration. Full article

This paper investigated sectoral water use and trends in the Mzimvubu to Tsitsikamma Water Management Area 7 (WMA7). The investigation considered the Water Authorisation and Registration Management System (WARMS) database and field surveys as a source of water use information. The study was able to successfully make use of time series statistical analysis to show water use trends for identified priority sectors over a 5-year period by sourcing historical water use data of the study area. Further, the groundwater stress index and streamflow impact were applied to assess water use impacts on the surface and groundwater. The WARMS database and field survey results identified major sectoral water users such as agriculture (irrigation), municipal water services, dam storage, afforestation, power generation, recreation, mining, and industries. Study findings revealed that the agricultural sector is a major water user, with an estimated 60% of the total water requirement over a 5-year period (2018 to 2022). The application of the groundwater stress index revealed that the majority of the Quaternary catchments have surplus groundwater available. The application of streamflow impact revealed that the majority of catchments have low flow or no flow. The rise of water use clearly indicates a lack of water use compliance and enforcement. An increase in total water use could put water resources under stress, including an impact on the aquatic ecosystem, reduced water quality, and economic and social consequences. Therefore, the study recommends that a follow-up on compliance of surface water and groundwater use licenses be regularly conducted. Full article

This study assessed riverbank erosion and stability along the Mekong and Bassac Rivers to propose safe river corridors and mitigate erosion risks in the Mekong Delta. Using Landsat imagery (2000–2023), field surveys, and numerical simulations, we identified severe erosion hotspots, where erosion rates reach up to 40 m annually, in the meandering sections of the Mekong River,. In contrast, the Bassac River exhibited significant sedimentation, though this trend was diminishing due to upstream sediment deficits caused by hydropower dams. Stability assessments revealed optimal safety corridor distances ranging from 20 to 38 m, influenced by local geotechnical conditions and structural loads. A significant proportion of riverbanks in Dong Thap (88%) and An Giang (48%) do not comply with conservation standards, exacerbating erosion risks and threatening infrastructure. The results of this study highlight the urgent need for enforcing conservation regulations, implementing nature-based solutions like riparian buffers, and adopting sustainable land-use planning. By addressing the interplay between natural processes and anthropogenic pressures, these findings offer actionable insights to enhance riverbank stability, protect ecosystems, and sustain livelihoods in the Mekong Delta amidst growing environmental challenges. Full article

Beavers (Castor fiber L.) are recognized as keystone ecological engineers who shape freshwater ecosystems by modifying hydrology, sediment dynamics, and biodiversity. Although beaver populations have recovered across Europe, including Romania, understanding the environmental factors driving their dam distribution remains limited. This study aimed to (i) characterize the physical and compositional features of beaver dams in the Râul Negru basin, Romania, (ii) model the environmental variables influencing the dam distribution using MaxEnt, and (iii) evaluate the implications for broader conservation strategies. Over a five-year survey covering 353.7 km of watercourses, 135 beaver families were identified, with an estimated population of 320–512 individuals. The dam dimensions showed strong correlations with the river slope, channel width, and wetness index. Predictive models based on LIDAR data achieved over 90% accuracy, outperforming SRTM-based models. The results reveal that topographic wetness, flow accumulation, and valley morphology are the strongest predictors of dam presence. These findings contribute to proactive beaver management strategies, highlighting areas of potential future expansion and offering data-driven guidance for balancing ecosystem restoration with human land use, contributing to the development of conservation strategies that balance ecosystem engineering by beavers with human land-use needs in Romania and across Europe. Full article

Dam and reservoir (D&R) systems, during their long history, have suffered from hundreds of failures, whose mechanisms have been accelerated by climate change and climate hazards. The following research question is posed: “which are the potentially significant climate hazards of D&R systems?” To answer this question, the vulnerability of D&R systems to climate change is assessed via a typologized methodology that is consistent with the technical guidelines of the European Commission on the climate proofing of infrastructure. The main steps of the methodology, which are (1) a description of the D&R system, (2) climate change assessment, and (3) vulnerability assessment, are performed using literature surveys, expert opinions, and climate models. The methodology is applied to the Almopeos D&R system in Greece, which is in the design stage, and the following conclusions are drawn: (1) the potentially significant groups of climate hazards are (i) temperature increase and extreme heat, (ii) precipitation decrease, aridity, and droughts, and (iii) extreme precipitation and flooding, and (2) the vulnerability assessment identified the climate indicators, the most important effects, and the most vulnerable components of the D&R system that can be used in the risk assessment that follows to identify the significant climate hazards and to propose targeted adaptation strategies to reduce their risks to an acceptable level. Full article

Anthropogenic influence has altered watershed environments and hydrological processes, leading to increased occurrences of impaired streams and negative impacts on benthic invertebrates. While individual environmental factors affecting benthic macroinvertebrates have been studied, the cascading effects of land use change and hydrological alterations remain unclear. This study employed structural equation modeling (SEM) to analyze the interactions among land use proportion, hydrological characteristics, substrate composition, and water quality and their influence on benthic macroinvertebrate communities in impaired streams upstream of the Paldang Dam in the Han River Basin, South Korea. Analysis of data from 24 streams surveyed between 2018 and 2022—3 or 6 streams per year—under the Impaired Stream Diagnosis Program indicated that urban and agricultural land cover, low substrate diversity, high pollutant concentrations, and altered flow conditions (low velocity and discharge) were associated with decreased pollution-sensitive Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa and increased pollution-tolerant and collector–gatherer taxa. These findings highlight the role of land use-driven hydrological changes in stream ecosystem degradation and underscore the need for targeted restoration strategies, such as riparian buffer zones, substrate enhancement, and hydrological flow restoration, to mitigate these impacts and improve benthic macroinvertebrate habitats. Full article

Check dams play a pivotal role in soil and water conservation engineering as they mitigate debris flow and decelerate the slope of the river channel by intercepting sediments, thereby preventing disasters. However, as ecological conservation and landscape integration have become significant, functions, safety, harmony, and aesthetics with the surroundings must be considered in the design of check dams. In this study, a questionnaire survey was conducted based on scenic beauty estimation (SBE) and image segmentation using artificial intelligence to evaluate the landscape quality of soil and water conservation projects. Data were collected from the photos which were segmented into vegetation, structure, sky, land, and water. The proportion of each segment was calculated to explore the relationship with the scenic beauty of the landscapes. Regions with prevalent vegetation and water received favorable evaluations, whereas areas with a higher proportion of land were less preferred. Even when vegetation was present in high quantities, an unorganized arrangement was less desirable. Identified key factors influencing the scenic beauty of the landscape can be considered in the design of soil and water conservation engineering projects. Full article

Understanding spatiotemporal patterns of fish density and their environmental drivers is critical for managing river–lake ecosystems, yet dynamic interactions in heterogeneous habitats remain poorly quantified. This study combined hydroacoustic surveys, spatial autocorrelation analysis (Moran’s I), and generalized additive models (GAMs) to investigate seasonal and spatial fish distribution, aggregation characteristics, and regulatory mechanisms in China’s Zhelin Reservoir. The results reveal pronounced seasonal fluctuations, with summer fish density peaking at 13.70 ± 0.91 ind./1000 m³ and declining to 1.95 ± 0.13 ind./1000 m³ in winter. Spatial heterogeneity was evident, with the Xiuhe region sustaining the highest density (15.69 ± 1.09 ind./1000 m³) and persistent hotspots in upstream bays. Transient high-density clusters (90–99% confidence) near the Zhelin Dam during summer suggested thermal or hydrodynamic disturbances. GAM analysis (R²adj = 0.712, 78.5% deviance explained) identified seasonal transitions (12.26% variance), water depth (16.54%), conductivity (13.75%), and dissolved oxygen (13.29%) as dominant drivers, with nonlinear responses to depth and bimodal patterns for conductivity/oxygen. These findings demonstrate that hydrological seasonality and habitat heterogeneity jointly govern fish aggregation, underscoring the ecological priority of Xiuhe and upstream bays as core habitats. This study provides a mechanistic framework for guiding reservoir management, including targeted conservation, dam operation adjustments to mitigate hydrodynamic impacts, and integrated strategies for balancing hydrological and ecological needs in similar ecosystems. Full article