Hasil untuk "Hydraulic engineering"

Sun Xinguo, Peng Anbang, Ma Shuaifei et al.

Urban areas are increasingly affected by intense rainstorm-induced flooding, posing serious risks to human life and property. To reduce the impact of such disasters and promote urban safety and sustainable development, a systematic assessment of Urban Flood Disaster Risk (UFDR), along with appropriate management strategies, is essential. Due to the high cost and complexity of acquiring and processing numerous potential indicators, identifying the most influential predictive variables is critical. This study integrates adaptive fuzzy logic with machine learning techniques to predict flood probabilities and develop evidence-based mitigation protocols. The proposed framework incorporates 13 carefully selected evaluation indicators, categorized into three dimensions: hazard triggers, environmental susceptibility, and community vulnerability. Indicator weights are determined through a combination of subjective (Analytic Hierarchy Process) and objective (CRITIC) weighting methods. Dynamic risk assessment is conducted using the Variable Fuzzy Pattern Evaluation (VFPE) model, while temporal features are automatically extracted using one-dimensional convolutional neural networks (1D-CNN). Flood probability is predicted using several machine learning algorithms, including Random Forest (RF), Decision Tree (DT), Extreme Gradient Boosting (XGBoost), and Support Vector Machine (SVM). The contribution of each input variable is assessed using feature importance scores derived from the RF model, averaged over a leave-one-out cross-validation (LOOCV) process. Results indicate that the SVM model achieves the highest accuracy and reliability for the multi-class classification task, particularly in identifying high-risk events. RF and XGBoost also demonstrate strong performance, offering a balance between predictive accuracy and model interpretability. Overall, the proposed methodology provides an effective and data-driven approach to support urban flood risk assessment and disaster mitigation planning.

Yuriy Kvach, Carol A. Stepien, Galyna G. Minicheva et al.

Abstract Background The effects of war on biodiversity, habitats, ecosystem services, and water, seafood, and fishing resources are complex and long-lasting, yet their ongoing environmental analyses are limited. The Russia–Ukraine War (2022–present) comprises a unique ecological situation to examine biodiversity effects on the distinctive cold-temperate northern Black Sea ecosystem, which has an intriguing biogeographic history and high endemism resulting from geographic isolation and differentiation. Results We summarize negative and positive effects from the War on the aquatic (marine, estuarine, and freshwater) biota and their habitats, focusing on investigations by the Institute of Marine Biology, National Academy of Sciences of Ukraine. Negative effects include toxins and habitat damage from oil spills, shelling, mining, explosions, flooding, and fires; along with disregard of Protected Areas. Positive effects are reduced anthropogenic loads from less shipping, fishing, trawling, recreation, hydraulic engineering, construction, and tourism. The Kakhovka Dam’s destruction on June 6, 2023 was the greatest ecological catastrophe to date, causing extensive downstream flooding with freshwaters and pollutants that destroyed many populations and habitats. We discern that many effects have been temporary, with habitats and species replenishing, and some reverting to their historical biota characteristic of lower salinity regimes. However, significant habitat destruction, disturbances, and pollutant damages remain. Since many of the native species evolved in conditions favoring broad salinity, temperature, and oxygen tolerances, the northern Black Sea ecosystem appears pre-adapted for ecological recovery and persistence, which may equate to ecological resilience during and after the War. Conclusions The native biota exhibits long-term adaptiveness to marked salinity and temperature fluctuations, alongside a background of invasive species. An evolutionary and recent history of broad environmental tolerances by a large proportion of Black Sea species may enhance their ability to withstand marked environmental changes, including habitat destruction, as during the Kakhovka Dam's breakage and other stressors that continue during the Russia–Ukraine War. The Black Sea community’s overall ecological resilience is likely to facilitate persistence and adaptation to the War’s effects and the accelerating impacts of climate change, increased global transportation, and invasive species—meriting worldwide conservation agency focus and cooperation.

HUANG Wenlin, SHAO Jing’an, WANG Chi et al.

【Objective】In the hilly and mountainous regions of Southwest China, improving irrigation efficiency is critical due to their complex terrains. This paper studies the inter-annual variation in irrigation water effective utilization coefficient (IWEUC) in these regions and identifies its main influencing factors.【Method】Taking Chongqing in the region as the study area, inter-annual changes in IWEUC were analyzed using data measured across 79 irrigation districts. Nine influencing factors categorized into four groups: natural conditions, resource availability, management practices and engineering infrastructure were selected in the analysis. Principal component analysis (PCA) was used to identify the dominant factors that influence IWEUC. 【Result】 ① IWEUC in Chongqing is lower than the national average due to the difficulty of implementing efficient irrigation in its mountainous terrains. While IWEUC has been growing over time, the growing rate has slowed in recent years. Spatially, IWEUC ranked from highest to lowest as southeast, west, main city and northeast. ② In irrigation districts with similar sizes, pumping-irrigation areas had higher IWEUC than free-flow irrigation areas, likely due to greater transmission efficiency of water in pipelines. However, free-flow irrigation areas showed faster growth in IWEUC. Medium-sized irrigation districts outperformed small-sized ones in absolute IWEUC, yet the latter demonstrated higher growth potential. ③ PCA results showed that areas with water-saving irrigation projects contributed most positively to IWEUC.【Conclusion】To further enhance irrigation efficiency in the mountainous regions of Southwest China, priority should be given to small-scale and free-flow irrigation districts, which have greater potential for improvement. Efforts should focus on improving irrigation management, optimizing water allocation, and expanding water-saving infrastructure, to enhance sustainable agricultural water use in these regions.

Maureen Denu, Frank Spörel, David Alós Shepherd et al.

Concrete segregation can lead to variations in hardened concrete’s properties, such as strength and Young’s modulus, or permeability, resulting in changing volume ratios between aggregates and paste within a concrete element. One approach to mitigate this potential risk is to conduct a performance test to assess vibrated concrete’s segregation sensitivity. This paper outlines various methods to evaluate the segregation sensitivity of vibrated concrete, aiming to support adequate concrete casting. The focus is on practical feasibility while maintaining test accuracy. For hydraulic engineering in Germany, test procedures to evaluate segregation sensitivity on fresh and hardened concrete based on aggregate distribution are described in the “BAW-Code of practice MESB”. However, this method is very complex and, therefore, difficult to implement in practice. Another procedure for hardened concrete is based on concrete density. In this paper, both methods are compared to investigate if evaluating fresh concrete using a simple density criterion leads to a comparably significant differentiation of vibrated concrete with different segregation sensitivities. The primary emphasis lies in accurately classifying examined concretes in terms of their segregation sensitivity, evaluating the scatter of results, and assessing the practical applicability of these methods. The investigations demonstrate that a density-based method can yield reliable and comparable results to those obtained through the wash-out test according to “BAW-Code of practice MESB”. Additionally, a simpler and faster procedure is achievable with the density approach. Hence, density evaluation offers a practical alternative to the wash-out test.

J. Costa

Guangjun Cui, Chunhui Lan, Cuiying Zhou et al.

Micron-scale crack propagation in red-bed soft rocks under hydraulic action is a common cause of engineering disasters due to damage to the hard rock–soft rock–water interface. Previous studies have not provided a theoretical analysis of the length, inclination angle, and propagation angle of micron-scale cracks, nor have they established appropriate criteria to describe the crack propagation process. The propagation mechanism of micron-scale cracks in red-bed soft rocks under hydraulic action is not yet fully understood, which makes it challenging to prevent engineering disasters in these types of rocks. To address this issue, we have used the existing generalized maximum tangential stress (GMTS) and generalized maximum energy release rate (GMERR) criteria as the basis and introduced parameters related to micron-scale crack propagation and water action. The GMTS and GMERR criteria for micron-scale crack propagation in red-bed soft rocks under hydraulic action (abbreviated as the Wmic-GMTS and Wmic-GMERR criteria, respectively) were established to evaluate micron-scale crack propagation in red-bed soft rocks under hydraulic action. The influence of the parameters was also described. The process of micron-scale crack propagation under hydraulic action was monitored using uniaxial compression tests (UCTs) based on digital image correlation (DIC) technology. The study analyzed the length, propagation and inclination angles, and mechanical parameters of micron-scale crack propagation to confirm the reliability of the established criteria. The findings suggest that the Wmic-GMTS and Wmic-GMERR criteria are effective in describing the micron-scale crack propagation in red-bed soft rocks under hydraulic action. This study discusses the mechanism of micron-scale crack propagation and its effect on engineering disasters under hydraulic action. It covers topics such as the internal-external weakening of nano-scale particles, lateral propagation of micron-scale cracks, weakening of the mechanical properties of millimeter-scale soft rocks, and resulting interface damage at the engineering scale. The study provides a theoretical basis for the mechanism of disasters in red-bed soft-rock engineering under hydraulic action.

Runzhi Xie, Xudong Wang, Beiyi Xu et al.

Study region: Lower Yangtze River alluvial plain, China. Study focus: The uneven subsidence caused by dewatering in underground engineering constructions in densely populated areas of alluvial plains with an unevenly distributed medium has caused increased concerns. This study applied the transition probability geostatistical software (T-PROGS) geostatistical models based on data from 31 boreholes to characterize a three-dimensional (3D) heterogeneous aquifer (8.8×105 m2 in area and 56 m in depth) in an underground construction area in the alluvial plain of the lower Yangtze River. The SUB model was constructed to simulate the pumping-induced subsidence processes based on a reliable MODFLOW transit flow model. New hydrological insights: The simulation results indicated that surface subsidence increased with pumping and reached a maximum of 33 mm by the end of the extraction (the 14th day). Surface subsidence development exhibited spatial anisotropy around the pumping center, consistent with the observations. Furthermore, the proposed model indicates that hydraulic head evolution and soil compressibility distributions significantly influence the spatial–temporal development of subsidence, implying the significance of the aquifer heterogeneity. The compressible soft soil overlying the pumping section was identified as a vulnerable subsidence zone, suggesting its significance for engineering geological surveys and dewatering designs in underground construction in alluvial plains.

Seah Yew Heng Sherman, Leong Eng Choon

Desiccation cracks in soils are important in engineering structures that need hydraulic integrity such as earth dams, and containment facilities. At the element test level, such cracks are a hindrance when the volume change of the soil specimen needs to be measured during the test. One such test is the volumetric shrinkage test where the volume of the soil specimen needs to be continuously determined together with its mass change as the soil specimen dries. The soil specimen may deform non-uniformly. Previously hazardous and cumbersome methods using mercury or wax are needed to determine the volume of soil specimens that deform non-uniformly, but the advent of 3D scanning and photogrammetry enables the volume of non-uniform soil specimens to be measured quite accurately. However, such techniques cannot accurately determine the volume of the deformed soil specimen once cracks start appearing in the soil specimen. Volumetric shrinkage tests are commonly conducted for cylindrical soil specimens. This paper investigates the geometry (shapes and dimensions) of soil specimens other than cylindrical on the formation of desiccation cracks. Bentonite is used as the test soil as it experiences large volume change on drying. The test results provide guidance for the geometry of a soil specimen to be used in the volumetric shrinkage test.

Yan-wei Fan, Chong Ren, Zhi-wei Yang et al.

Moistube irrigation is a new micro-irrigation technology. Accurately estimating its wetting pattern dimensions presents a challenge. Therefore, it is necessary to develop models for efficient assessment of the wetting transport pattern in order to design a cost-effective moistube irrigation system. To achieve this goal, this study developed a multivariate nonlinear regression model and compared it with a dimensional model. HYDRUS-2D was used to perform numerical simulations of 56 irrigation scenarios with different factors. The experiments showed that the shape of the wetting soil body approximated a cylinder and was mainly affected by soil texture, pressure head, and matric potential. A multivariate nonlinear model using a power function relationship between wetting size and irrigation time was developed, with a determination coefficient greater than 0.99. The model was validated for cases with six soil texture types, with mean average absolute errors of 0.43–0.90 cm, root mean square errors of 0.51–0.95 cm, and mean deviation percentage values of 3.23%–6.27%. The multivariate nonlinear regression model outperformed the dimensional model. It can therefore provide a scientific foundation for the development of moistube irrigation systems.

A. Katende, Lisa O'Connell, A. Rich et al.

C. Liang, Mohammad Askari, Looh Tchuin Choong et al.

Osmotically assisted reverse osmosis (OARO) has become an emerging membrane technology to tackle the limitations of a reverse osmosis (RO) process for water desalination. A strong membrane that can withstand a high hydraulic pressure is crucial for the OARO process. Here, we develop ultra-strong polymeric thin film composite (TFC) hollow fiber membranes with exceptionally high hydraulic burst pressures of up to 110 bar, while maintaining high pure water permeance of around 3 litre/(m2 h bar) and a NaCl rejection of about 98%. The ultra-strong TFC hollow fiber membranes are achieved mainly by tuning the concentration of the host polymer in spinning dopes and engineering the fiber dimension and morphology. The optimal TFC membranes display promising water permeance under the OR and OARO operation modes. This work may shed new light on the fabrication of ultra-strong TFC hollow fiber membranes for water treatments and desalination. Osmotically assisted reverse osmosis can overcome limitations of the reverse osmosis process but a strong membrane which can withstand a high hydraulic pressure is crucial. Here, the authors develop strong polymer thin film composite hollow fiber membranes with exceptionally high hydraulic burst pressures of up to 110 bar, while maintaining high water permeance and salt rejection.

Chrissy Mitchell

L. Björkman

Mousumi Ghosh, Mohit Prakash Mohanty, Pushpendra Kishore et al.

This study proposes a novel comprehensive hydrodynamic flood modelling framework over Mithi river watershed in Mumbai, India, a coastal urban area, to reduce the inundation extent by incorporation of different inland hydraulic scenarios. First, the study addresses the issue of data scarcity by adapting alternate robust techniques to estimate design rainfall, tidal elevation and discharge, the key inputs for a flood model. Following that, a three-way linked flood model has been developed in the MIKE FLOOD platform, considering river, stormwater, overland flow and tidal influence to generate flood inundation and subsequently hazard maps for various inland hydraulic scenarios, by incorporating different feasible cross-sections and lining materials. The flood inundation and hazard maps have been derived for 10-, 50- and 200-year return periods of design rainfall, discharge and tide to identify the best possible flood-reducing hydraulic scenario. It is observed that a ‘trapezoidal river cross-section lined with concrete’ relatively maximizes the reduction in flooding extent. The proposed framework can be implemented as an effective flood mitigation strategy in data-scarce, densely populated and space-constrained areas. HIGHLIGHTS This study proposes a novel comprehensive hydrodynamic flood modelling framework to reduce the inundation extent by incorporation of different inland hydraulic scenarios considering various combinations of cross-sections and lining material options.; The maps are derived for 10, 50, and 200 year return periods of design rainfall, discharge and tide to identify the best possible flood-reducing hydraulic scenario.; This easy-to-implement, user-friendly framework has the potential based on modifications along the river channel of being an effective flood mitigation strategy, especially in data-scarce areas, socially-relevant set-ups, and densely populated and space-constrained areas where implementing structural measures like construction of dams, reservoirs etc., are no simple panacea.; The area considered in this study comprises the Mithi river catchment – a highly flood-prone region in Mumbai, the commercial capital of India.; This framework would prove beneficial particularly for densely populated urban catchments wherein space constraints render the adaptation of structural measures for flood management difficult.;

J. G. Williams, Greg Amstrong, C. Katopodis et al.

H. Azamathulla, A. Haghiabi, A. Parsaie

Ekaterina M. Bogutskaya, Aleksey G. Kositskiy, Denis N. Aybulatov et al.

The authors have studies the regularities of the mean annual runoff of the rivers at the Crimean Mountains Northwestern slopes on the basis of the hydrological stations’ data. For all station, including the closed ones, that data were unified against a single manyyear uniform period for which we calculated mean annual water flows and runoff modules. It has been stated that mean annual runoff modules, in contrast with the most of small rivers of Russia are decreasing with the increase of catchment areas and the river hydrographic length, and this is associated with the evaporation effects. In addition, we have found diminishing dependence of mean many-year runoff modules on remoteness from the sea and increasing dependence on the catchment average height. We have stated that it were these above factors that decisively effect on the Kacha, Belbek, and Chernaya rivers runoff formation, particularly in the downstream were the watercourses face anthropogenic impact. These rivers have catchment areas exceeding 250 km2 . The anthropogenic factors impact upon formation of the mean annual runoff is not so significant in comparison with that for rivers with lesser catchment areas. However, any hydrological station data supporting this fact are not available.

M. Shahin, M. Jaksa, H. Maier

Leila Goodarzi, Abbas Roozbahani

Climatic parameters including temperature and precipitation have an important role in  water resources management of river basin as well as agricultural planning. Time series models are a kind of short-term prediction for these parameters. Precipitation is one of the most important climate parameters that should be addressed in water resources management. This is especially important in Iran, with an average annual rainfall of about 250 mm. Another climate parameter is temperature, which changes the climate structure of each location. For this reason, the study on temperature at various time and space scales has been addressed in a large part of the climatological researches. Time series analysis is widely used as a tool for temperature and rainfall predictions. So far, various studies have been done to predict climate and hydrologic parameters using time series analysis models. Kaushik and Singh (2008) predicted  monthly temperature and precipitation in India using the seasonal Arima Model. There are also other researchers focused on application of ARMIA model such as Naill and Momani (2009), Tularam and Ilahee (2010) and Mondal et al. (2014). Holt Winters is also one of the time series models used for prediction. For example, Costa et al. (2015) predicted  water quality parameters using the Holt Winters model and presented its effectiveness in the prediction. <br />In this research, the ability of time series models for forecasting  monthly temperature and precipitation of Latian station in Iran has been examined. Trend analysis was conducted using the Seasonal Mann- Kendall test and then, various Autoregressive Integrated Moving Average Models (ARIMA) as well as Holt Winters model were fitted to the data and the best time series model was finally selected.