Hasil untuk "Hydraulic engineering"

ZHANG Chengyan, BAO Lingling, YE Yizhou et al.

To overcome the limitations of previous analyses examining drought evolution from solely temporal or spatial perspectives and to better capture the complete developmental process of meteorological drought events, this study employs a three-dimensional (3D) drought identification method integrating spatiotemporal connectivity, based on the SPI-3, to systematically reveal the spatiotemporal dynamic evolution patterns of meteorological drought events in Wenzhou City, a pivotal coastal area in southeastern China. The methodology involves defining drought events as coherent spatiotemporal clusters where the SPI-3 is below the moderate drought threshold (-1), meticulously tracking their initiation, migration, expansion, contraction, and termination. The analysis utilizes high-quality monthly precipitation data (1961-2019) from 22 meteorological stations, spatially interpolated to a 1-km resolution grid, alongside SRTM DEM data for topographical context. The core 3D identification process comprises two key steps: first, identifying independent drought patches in each month by merging contiguous drought grids and applying an area threshold (≈1.6% of the study area, 193.6 km²); second, temporally connecting patches across consecutive months based on spatial overlap exceeding this threshold, thereby constructing 3D drought structures characterized by duration, area, intensity (volume), and centroids. Results identify 131 distinct meteorological drought events in Wenzhou from 1961 to 2019. Temporally, overall trends in drought duration, area, and intensity show a fluctuating decline, with distinct phases: a significant decrease before 1995, an increase followed by a decrease between 1995 and 2005, and relatively stable duration/intensity but fluctuating area post-2005, indicating a shift towards more widespread but less intense/short-lived events. Seasonally, droughts exhibit high incidence in summer (27.53%) and autumn (26.96%), with October (13.7%) and July (13.0%) being the peak months. Spatially, drought centers are predominantly concentrated in inland areas farther from the coast, with Yongjia, Ouhai, Ruian, and Pingyang districts experiencing particularly long-duration and high-intensity events, highlighting a clear correlation with topography and land-sea position. Analysis of the ten most severe events and detailed 3D case studies demonstrates that the reconstructed spatiotemporal evolution—including development paths, changing spatial footprints, and centroid migration—aligns remarkably well with historical drought records from Wenzhou. This consistency robustly validates the reliability and practical utility of the proposed SPI-based 3D identification method. Consequently, this study not only provides novel insights into the intricate spatiotemporal dynamics of droughts in a complex coastal environment but also offers a refined methodological framework for improved regional drought monitoring, dynamic tracking, and early warning. The findings furnish a detailed scientific basis for formulating targeted drought risk prevention, control strategies, and resilience enhancement in Wenzhou and similar monsoonal coastal regions.

Hugo Hernández-Gamboa, Oscar Iván Reyes-Maya

Las disputas urbanas en torno al agua, aunque han sido un tema constante en ciudades de todo el mundo, solo recientemente han impulsado análisis interdisciplinarios, especialmente desde enfoques teóricos llamados híbridos, como la ecología política urbana, que busca desentrañar la compleja relación entre lo político y el recurso hídrico en ámbitos metropolitanos. Este artículo se centra en analizar las alteraciones en el ciclo hidrosocial de Ecatepec, de la Zona Metropolitana del Valle de México, provocadas por el "huachicoleo" (robo de agua mediante tomas clandestinas) y sus consecuencias políticas. Se indaga si el huachicoleo busca hacer valer los derechos políticos de los ciudadanos carentes del recurso y desmantelar las redes políticas-clientelares ligadas con la precariedad hídrica. A diferencia de otros estudios, este análisis no se limita a las estrategias empleadas por aquellos que ostentan el poder sobre aquellos que carecen de él, sino que se adentra en las complejidades de la interacción. La metodología incluyó trabajo de campo y entrevistas semiestructuradas a vecinos y empleados del organismo operador de aguas del municipio durante los años 2020 y 2021. Se concluye que aunque el huachicoleo no busca primordialmente desafiar las redes de poder que limitan los derechos políticos ha tenido un impacto disruptivo en los flujos de agua y las dinámicas de poder en la región.

Yan DU, Hongda ZHANG, Mowen XIE et al.

Large-scale rock collapse is a prevalent geological hazard in China, characterized by complex causes, wide distribution, strong concealment, sudden onset, and significant destructiveness, making early warning challenging to achieve. The instability mechanisms and warning models of rock collapse disasters vary widely. Scientific identification of damage to rock bridge structural surfaces is essential for early warning and prevention of these disasters. Conducting damage identification of rock bridge structural surfaces and comprehensive monitoring research, which includes static, dynamic, and environmental indicators (SDEI), is key to early monitoring and warning of large-scale rock collapses. The study of early warning mechanisms based on the identification of separation damage precursors is an effective means to enhance the timeliness of early warnings for such disasters. With the development of micro-electromechanical systems and cloud-edge collaboration technology, a new multivariate early warning paradigm is expected to emerge in the future. This paradigm would feature real-time linkage of dynamic stability evaluation, unstable working condition prediction, and failure time prediction models. It is also necessary to continuously enrich the early warning technology system for brittle failure disasters, such as large-scale rock collapses, to achieve real-time analysis of warning levels, stability status, unstable conditions, and timing of dangerous rock masses, effectively addressing the dual challenges of scientific and accurate prevention and control of large-scale rock collapse disasters and intelligent emergency decision-making. Finally, several development strategies and countermeasures are proposed to overcome the technical bottlenecks in current early monitoring and warning research. For instance, in the field of theoretical research on monitoring and early warning, it is crucial to investigate the causes and early warning mechanisms of brittle destruction disasters such as large-scale collapses. In terms of monitoring equipment development, promoting the development of domestic equipment that integrates dynamic indicators and SDEI is necessary. Building a monitoring and early warning index system based on the integration of multi-source information from SDEI is essential in the research on monitoring and early warning index systems. The development of intelligent monitoring and early warning technology based on cloud-edge integration should be steadily advanced. In terms of data collection for case studies of large-scale dangerous rock mass collapse disasters, comprehensively constructing the SDEI database for various large-scale dangerous rock mass collapse case monitoring samples should be undertaken, ultimately forming a virtuous development cycle of research on theoretical models of large-scale dangerous rock mass collapse disasters, development of monitoring equipment, construction of index systems, development of early warning technology, and database upgrading and improvement. These measures can provide some reference for better responding to large-scale rock collapse disasters in high-risk geological hazard areas.

LI Jiong 1, 2, 3, LI Mingguang 1, 2, ZHAN Hongbing 4, CHEN Jinjian 1, 2, XIA Xiaohe 1, 2

To address the issue that the traditional models of well hydraulics for constant-head tests (CHTs) fail to reflect the effects of the clogging in well vicinity on groundwater flow dynamics, a semi-analytical model of the groundwater hydraulics in well vicinity is developed for CHTs using partially penetrating wells. A combination of variable substitution, Laplace transform and finite Fourier cosine transform is used to develop the solutions for the proposed model in the Laplace domain. Then, the solutions in the real-time domain are obtained using the Stehfest numerical Laplace inversion method. A parametric study of the developed solution indicates that a smaller asymptotic hydraulic conductivity Kr, ∞ leads to the smaller hydraulic head increment s and the less injection flux Q and reduces the quasi-steady flow dynamics of the recharged aquifer, while a larger permeability reduction exponent λ decreases s and Q only in the middle stage of the injection tests but has few effects on the quasi-steady flow dynamics. The hydraulic head difference due to various values of Kr, ∞ and λ first increases and then decreases with the radial distance and reaches its maximum value at the interface of the clogging region and the formation. The clogging in well vicinity results in an obvious inflection point at the outside boundary of the clogging region on the distribution curve of s and leads to an apparent decreasing stage of the history curve of s, which can offer theoretical reference for the evolution and prediction of the clogging development.

M. Babaei, M.T. Sattari

IntroductionDevelopment of reservoirs helps to meet food and energy needs by supplying water for agriculture and hydropower plants. Efficient management of water resources is important and vital to overcome the problems of water leakage and meet agricultural, industrial and drinking needs. Each of these requirements creates limitations in the way the reservoir is operated, which requires accurate information on the changes in the reservoir storage and other influential components during the operation period. In order to manage and plan water resources at country scale, using reservoir simulation models as a suitable tool in simulating processes related to dams, such as the operation of water reservoirs, will be very effective. Reservoir simulation models such as the HEC-ResSim model provide the opportunity to simulate the natural and hydrological processes related to the water resources system and the relationships between the supply and demand sectors by implementing a schematic structure of a real reservoir. Two scenarios of water savings of 20 and 30 percent were used in the current investigation.  Additionally, using this method, the objectives of water resource management can be assessed.Materials and MethodsIn the present study, the use of the Latian reservoir in real conditions was simulated using the HEC-ResSim model. The simulation was carried out according to the river's inflow from 1968 to 2018, downstream water needs, energy production capacity by turbines, physical characteristics and reservoir building. The implementation of the HEC-ResSim model is summarized in three steps. The Watershed Setup module is used to introduce the general outline of the watershed. In this module, the shape and geographical location of the basin and related elements such as rivers, reservoirs, hydrometric stations and other projects in it should be specified. The Reservoir Network module is used to introduce the desired reservoir network and to enter the physical characteristics and how to use them. The Simulation module is designed to introduce the simulation period and display the model outputs.  In this module, the simulation time and period and the operation pattern should be determined.Results and DiscussionAccording to the results obtained from the reservoir simulation model, the average storage capacity of Latian dam for the simulation period was estimated to be 41 million cubic meters, which shows a significant drop of 49% compared to the normal level (83 million cubic meters). Additionally, for the same period, it was estimated that the average discharge was equivalent to 5.4 cubic meters per second and the average inflow to the reservoir of the Latian dam was equal to 5.7 cubic meters per second. This is in contrast to the period's average demand, which for the area downstream of the Latian Dam is 12.1 cubic meters. The findings indicate that the reservoir of the dam frequently, and particularly at the conclusion of the simulation period, is unable to satisfy the needs of the downstream. Additionally, according to the findings of the current study, the Latian dam power plant's (Kalan) average annual hydro-electric energy production was projected to be 68,000 MWh, and the results show that in accordance with the policy of operating the Latian dam in the majority ofthe years, the Kalan power plant is able to supply the electricity required in the study area. According to the results, the average reservoir volume of Latian dam for the entire period in the first and second scenario was estimated to be 49 and 63 million cubic meters, respectively. Also, by applying the first and second water saving scenarios, the Latian dam reservoir will be able to generate 66,000 and 63,000 MWh of energy annually.ConclusionIn this study, the functioning and operation of the Latian dam reservoir was used by applying the Hec-ResSim reservoir simulation model. After entering data such as the elevation and length of the dam, surface-volume-elevation curve, evaporation from the surface of the reservoir, elevation and uncontrolled outlet coefficient, dam storage areas, rule curve, were simulated by the model. In the present study, the values of inactive volume and conservation volume of Latian Dam were estimated as 28 and 83 million cubic meters, respectively. The average water release of Latian dam for the first and second 25 years of operation was equal to 6.1 and 3.7 cubic meters per second, respectively, which met 50 and 32% of the downstream demand on average. The results indicate that the success rate of Latian dam in supplying drinking, industry and downstream environment for the period of operation is 42%. Also, 16 years out of 50 years of operation, Kalan hydropower plant has fully met 100% of the needs. On average, the large power plant is able to provide 80% of the energy needs of the study area for the entire simulation period.

Xiaoxiao Hao, HongGuang Sun, Shiyin Li et al.

Nanoparticles have been applied to remediate heavy metal pollutants (e.g., arsenic) in groundwater and soil, where the migration mechanism of pollutants in this multi-component system has not been fully understood. To better understand how nano-iron oxide affects arsenic migration under multivariate influence, this study prepared arsenic loaded composite colloids using arsenic (As(V)), humic acid, and nano iron oxide (n-α-Fe2O3). Then we explored the migration behavior of the composite colloids (HA-n-α-Fe2O3) loaded As(V) in a quartz sand column affected by n-α-Fe2O3 under various humic acid concentrations, pH values, ionic strengths, and ferric oxide contents. Two migration models, including a classical advection-dispersion equation (ADE) and a Hausdorff fractal advection-dispersion equation (HADE), were used to quantify the observed co-migration of arsenic conveyed by HA-n-α-Fe2O3 colloids loaded As(V) in the column. Our analysis indicates that the adsorption capability of nano-iron oxide on arsenic decreases with pH, humic acid and iron oxide concentrations, thus accelerating arsenic movement. While, the increasement of ionic strength enhances the adsorption force of nano-iron oxide on arsenic and suppresses arsenic migration. Furthermore, simulation results suggest that the HADE model outperforms the traditional ADE model in characterizing arsenic migration, where the time derivative index is an indicator of anomalous diffusion.

ZHENG Defeng, ZHAN Shiyao, CAO Yongqiang

The spatiotemporal dynamic characteristics of regional potential evapotranspiration can lay a theoretical foundation for regional rational crop planting and scientific agricultural irrigation.In the context of global warming and increasing evapotranspiration rates,the Penman-Monteith equation is used to calculate the potential evapotranspiration (ET₀) and water budget (K) of Hebei Province from1967 to 2019 according to the actual meteorological observation data of twelve weather stations in Hebei Province,and the characteristics of their spatiotemporal dynamic variations are analyzed.On this basis,the analysis method of the Morlet wavelet function is introduced for the cycle analysis of ET₀ and K in 53 years.The results show that ET₀ has obvious zonal characteristics,and it is generally on the rise while K is on the decline during this period.Moreover,the evapotranspiration variations vary with seasons:ET₀ shows an upward trend in spring,autumn,and winter but a downward trend in summer.The cycle of K has the most significant oscillation at 35 a,and the scope of the oscillation is prominent in summer and autumn.Therefore,obvious changes in seasonal characteristics of Hebei Province have a great impact on K.The results can provide a reliable theoretical basis for agricultural water-saving and planting structure adjustment in Hebei Province.

Verónica Sykora, Araceli Clavijo, Daniel Calvo et al.

La inclusión de los análisis ecotoxicológicos en los estudios ambientales resulta indispensable, pues aporta información sobre los efectos que los contaminantes puedan causar en los organismos expuestos y en los ecosistemas receptores. El objetivo del trabajo fue evaluar la calidad del agua en la cuenca del arroyo Cañuelas (Buenos Aires, Argentina), a partir de determinaciones fisicoquímicas y de bioensayos ecotoxicológicos estandarizados en diferentes niveles tróficos con los organismos: Pseudokirchneriella subcapitata, Lactuca sativa y Caenorhabditis elegans. Las muestras se extrajeron de cuatro puntos de muestreo representativos a lo largo del cauce de los arroyos Cañuelas y Navarrete. P. subcapitata y la raíz de L. sativa presentaron los valores más altos de inhibición del crecimiento en los puntos de muestreo coincidentes con un mayor deterioro de la calidad del agua de acuerdo con los niveles propuestos por la normativa local. Por el contrario, C. elegans reveló toxicidad en muestras cuyos parámetros fisicoquímicos cumplieron con la normativa vigente. Los resultados de este trabajo respaldan la necesidad de incorporar una batería de bioensayos ecotoxicológicos que complementen los análisis fisicoquímicos y contribuyan a una mejor gestión de los recursos hídricos.

Hossein Tabari, Parisa Hosseinzadehtalaei, Wim Thiery et al.

Abstract The economic stress and damage from natural hazards are escalating at an alarming rate, calling for anticipatory risk management. Yet few studies have projected flood and drought risk, owing to large uncertainties, strong non‐linearities, and complex spatial‐temporal dynamics. Here, we develop an integrative global risk analysis framework encapsulating future changes in flood and drought hazards as well as associated exposure and vulnerability dimensions. Flood characteristics are quantified by fitting a generalized extreme value distribution (GEV) to the annual flow maxima time series, while drought properties are characterized by the standardized precipitation evapotranspiration index (SPEI) and the standardized precipitation index (SPI). The drivers of drought and flood risk changes at the global and regional scales are explored, and the wide cascade of uncertainties in the risk assessment is decomposed. We find a substantial increase in both flood and drought risk towards the end of the century over most of the globe, driven by compounding changes in exposure, vulnerability, and hazard. A shift from a fossil‐fueled development to a sustainable one decreases the global area facing a risk doubling from 61% to 33% for flood and from 41% to 23% for drought. South America and Africa are identified as hotspot regions where a concomitant, large increase in both flood and drought risk are projected. The hazard quantification method is ubiquitously the dominant uncertainty source for drought risk changes, while the contribution of uncertainty sources for flood risk changes is highly variable in space.

Yingchun Li, Chuangzhou Wu, B. Jang

Z. Yin, Jie Yang, F. Laouafa et al.

Abstract In order to study the impact of internal erosion at the scale of an engineering structure, a hydro-mechanical continuous modelling approach considering suffusion is needed. It requires a relevant mechanical model for granular soils considering the -dependency ( fines content) and a hydraulic model for suffusion to control the changes in the fines content. To this purpose, the mechanical models for granular soil, the unified modelling approaches for -dependency of granular soils and the hydraulic modelling of suffusion are first reviewed. Then, a hydro-mechanical model considering both suffusion and mechanical loading is developed by combining the three components. For each component of the model, alternative choices are provided. Simulations of laboratory tests as well as an example of a dike-on-foundation problem demonstrated the reliability and applicability of this coupled numerical approach for internal erosion problems.

Wei Zhang, B. Dai, Zhen Liu et al.

Gopchak Igor, Basiuk Tetiana, Bialyk Ihor et al.

The environmental assessment of the surface water quality of the Western Bug River has been made using the system of classification quality of land surface water of Ukraine in accordance with the approved methodology, which allows comparing water quality of separate areas of water objects of different regions. The calculation of the environmental assessment of water quality has been carried according to three blocks: block of salt composition, block of trophic and saprobic (ecological and sanitary) indicators and block of indicators of content of specific toxic substances. The results are presented in the form of a combined environmental assessment, based on the final conclusions of the three blocks and consists in calculating the integral ecological index. Comprehensive studies of changes in the water quality of the Western Bug River have been conducted within the territory of Ukraine for a long-term period. The water quality of the river on the final values of the integral indicators of the ecological condition corresponded mainly to 4nd category of the 3rd class – the water is “satisfactory” by condition and “little polluted” by degree of purity (except for points of observation that located within the Volyn region, where the water quality corresponded to 3rd category and the 2nd class. It is “good” by condition and “fairly clean” by the degree of purity). Visualization and part of the analysis are performed using GIS technologies in the software of the ArcGIS 10.3.

Xiaoya Tang, Guangyan Liu, J. Yang et al.

H. Farhadian, H. Katibeh, P. Huggenberger

Hongli Chen, Min Li, Z. Lv et al.

Kaman Thapa Magar, Mark Balas, Susan Frost et al.

A class of adaptive disturbance tracking controllers (ADTCs) is augmented with disturbance and state estimation and adaptive state feedback, in which a controller and estimator, which are designed on the basis of a lower-order model, are used to control a higher-order nonlinear plant. The ADTC requires that the plant be almost strict positive real (ASPR) to ensure stability. In this paper, we show that the ASPR property of a plant is retained with the addition of disturbance and state estimation and state feedback, thereby ensuring the stability of the augmented system. The proposed adaptive controller with augmentation is presented in the context of maximum power extraction from a wind turbine in a low-wind-speed operation region. A simulation and comparative study on the National Renewable Energy Laboratory’s (NREL’s) 5 MW nonlinear wind turbine model with an existing baseline Proportional-Integral-Derivative(PID) controller shows that the proposed controller is more effective than the existing baseline PID controller.

Ding Li, Shikun Zhang, S. Zhang