Hydraulic Scenarios Research Articles

The Water–Energy Nexus in 26 European Countries: A Review from a Hydrogeological Perspective

The significance of the interconnection between water and energy, known as the water–energy (WE) nexus, is highly regarded in scientific publications. This study used a narrative review method to analyze the existing WE nexus studies performed before 2024 in 26 European countries. The aim of this study is to provide a comprehensive analysis of the existing WE nexus to identify research gaps and to report a conceptual overview of energy consumption related to groundwater use phases, ranging from the tapping to distribution. This information is valuable as a guideline for any future estimates in this field. The results indicate that the WE nexus in 26 European countries comprises a variety of topics, including the water supply system, wastewater treatment, hydropower, desalination, and biofuel production. Most of the focus has been on fossil fuel production, while water supply and desalination were considered rarely. Italy and Portugal had the largest WE nexus. It is highlighted that there have been no studies on the WE nexus focusing on the groundwater supply system that consider the conceptual hydrological model or hydrodynamic processes. In this work, a view of these aspects was provided by taking into account different hydrogeological and hydraulic scenarios that may affect the amount of energy required for groundwater exploitation. Most scientific publications have focused on quantitative analysis. In the future, it will be necessary for WE nexus models to place a greater emphasis on governance and the implications of the WE nexus approach.

Assessing the Efficiency of Fully Two-Dimensional Hydraulic HEC-RAS Models in Rivers of Cyprus

Floods are among the most widespread and recurrent natural disasters globally. In the European region, climate change leads to an increase in the incidence and intensity of flooding. For effective management of the phenomenon, the European Union instituted Directive 2007/60/EC for the assessment and management of flood risks in order to reduce the negative consequences of flooding on human health, economic activities, the environment, and cultural heritage. Cyprus, as a member of the European Union, had to comply with the provisions of the directive. Within the second implementation of the directive, combined 1D/2D hydraulic models were conducted. These data served as a benchmark for the present research, in which the differences in the inundated area, depths, and simulation time are investigated using a full 2D hydraulic simulation. The present research examines two Areas of Potentially Significant Flood Risk, one in an urban and one in a rural area. Overall, the proposed 2D methodology was found to represent inundated areas to a good extent with almost zero deviation in comparison to the 1D/2D method. This study demonstrated the adequacy of the 2D hydraulic simulation method, which offers greater flexibility in modeling a variety of hydraulic scenarios, enabling planning and flood risk management that is vital for protecting communities, infrastructure and the environment from the devastating impacts of floods.

A CFD-based compartmental modelling approach for long-term dynamic simulation of water resource recovery facilities

ABSTRACT This article presents a methodology for compartmental model (CM) creation for long-term simulation of water resource recovery facilities (WRRFs). CMs are often focused on reproducing with a lower computational cost, previously simulated scenarios. In contrast, the methodology presented here can represent variable hydraulic conditions, based on the interpolation of data gathered from a set of computational fluid dynamics (CFD) simulations that reproduce representative hydraulic scenarios. This is achieved by modelling with bidirectional flows the exchange flows between fixed compartments, which are defined based on the geometry of the reactors. The resultant hydraulic surrogate model can be implemented in commercial water treatment software to solve biochemical kinetics. The methodology was applied to simulate in WEST®-DHI a WRRF in Vila-Real, Spain. In this contribution, the CM was validated with real plant data. The developed CM provided a quick response simulation with a high level of hydraulic and biochemical detail. This allowed observation of a spatial distribution of component concentration, which could help with sensor location or plant optimisation. The methodology presented here could also be a useful enabler of digital twins to be implemented in WRRF.

Explicit Scheme for a Hydrological Channel Routing: Mathematical Model and Practical Application

The computation of hydrographs in large watersheds necessitates utilizing channel routing, which calculates the movement of hydrographs along channel branches. Routing methods rely on an implicit scheme to facilitate numerical resolution, which requires more computational time than the explicit scheme. This study presents an explicit scheme channel routing model that offers a versatile approach to open channel flow analysis. The model is based on mass conservation principles and Manning equations, and it can accommodate varying bed slopes, making it highly adaptable to diverse hydraulic scenarios. In addition, the proposed model considers backwater effects, which enhances its applicability in practical scenarios. The model was tested in a practical application on a rectangular channel with a width of 7 m, and the results showed that it can accurately predict outflow hydrographs and handle different flow conditions. Comparative analyses with existing models revealed that the proposed model’s performance in generating water flow oscillations was competitive. Moreover, sensitivity analyses were performed, which showed that the model is highly responsive to parameter variations, such as Manning’s coefficient, bed slope, and channel width. The comparison of peak flows and peak times between the proposed model and existing methods further emphasized the model’s reliability and efficiency in simulating channel routing processes. This research introduces a valuable addition to the field of hydrology by proposing a practical and effective channel routing model that integrates essential hydraulic principles and parameters. The results of the proposed model (lumped routing) are comparable with the solution provided by the Muskingum–Cunge method (distributed routing). It is of utmost importance to note that the proposed model applies to channel branches with bed slopes below 6°.

Experimental investigation of the total flow resistance in emergent and submerged rigid canopy flows

In canopy flows, flow resistance mainly originates from vegetation drag and depends on vegetation characteristics and flow conditions. In the present study, a series of experiments were performed in various hydraulic scenarios with high stem Reynolds numbers (2641 ≤ Red≤ 17333) using relatively sparse rigid canopies, represented with four different dimensionless vegetation densities (0.0044, 0.0098, 0.0174 and 0.0392), on a smooth bed. A novel drag plate mechanism was developed to measure the total flow resistance due to the emergent and submerged vegetation arrays in a staggered pattern under subcritical flow conditions. Manning’s roughness coefficient and Darcy–Weisbach friction factor were adopted to represent the total flow resistance in the analyses. Simple empirical relationships based on roughness concentration and submergence ratio were derived to determine the total flow resistance parameters within a broad range of stem Reynolds numbers. Although relationships were proposed in a simple form to be used for direct practical applications, they show similar or better performance in the prediction of total flow resistance parameters than the existing equations in the literature, which require considerable computational effort. Additionally, analyses demonstrated that the results of the present study and those of similar studies regarding canopy flow resistance are in good agreement. Accordingly, the novel drag plate looks promising for measuring flow resistance due to vegetation and bed conditions similar to those in nature.

Impact of aging infrastructure on water pressure and quality: Guelma water network simulation

ABSTRACT AQUA – Water Infrastructure, Ecosystems and Society issues a formal withdrawal in relation to the above article by Kherouf Mazouz, R. Mansouri and M. Dorbani. This decision has been taken due to concerns about the validity and reliability of the conclusions, and the originality of the article.

Performance of a low-cost hydraulic ram pump as a function of variations in feed height and inlet pipe diameter

Access to water in rural areas is extremely important in the different activities that occur daily on agricultural properties, whether for human consumption, animal watering, irrigation and other purposes. This access is often difficult and costly, especially for small rural producers who do not have the financial capacity to purchase an electric pump, or do not have electricity on their property. In this sense, alternative water pumping, without the need to use electrical energy or energy from the burning of fossil fuels, can be a good alternative and deserves to be studied. Based on these premises, the objective of this research was to study the performance of the repressed flow, obtained by a low-cost hydraulic ram, installed in different hydraulic scenarios. The methodology consisted of installing equipment built in the Irrigation, Hydraulic and Hydrology Laboratory of the Agricultural Sciences Center of the State University of the Tocantina Region of Maranhão (LIHH/CCA/UEMASUL), for this, different hydraulic scenarios were created depending on the interaction of different feeding heights and different pipe diameters, which constituted the experimental treatments. The results found allowed us to conclude that the highest average pressure flow was obtained in the hydraulic scenario that presented the greatest geometric difference between the water source and the hydraulic ram with the largest diameter of the inlet pipe, with an average of 9,539.21 L.d-1 of repressed water. It was also possible to prove that this equipment constitutes a good alternative for pumping water on small rural properties.

Respiro dell'acqua ad Ho Chi Minh city

The research entitled Flood Risk Management Prevention, Adaptation and Resilient Strategies in Ho Chi Minh city, the partial outcomes of which are presented in this text, is framed within the Projects of Great International Relevance of the Italian Ministry of Foreign Affairs and International Cooperation for the consolidation of bilateral relations between Italy and Vietnam. The University of Trento, the IUAV University of Venice and the Vietnam National University are working together to propose alternative landscape and hydraulic scenarios to face the challenges posed by the excessive anthropic load and climate change that squeeze and weaken the river landscape of the metropolis, not allowing the fragile lacustrine territories to breathe adequately.

Microplastic transport dynamics in surcharging and overflowing manholes

The transport of microplastics within urban water systems remains poorly understood, with little prior research on their behaviour within manhole configurations. This study represents the first to measure and model the transport dynamics of microplastics within circular and square manholes under different hydraulic scenarios. The transport and fate of polyethylene (PE) was quantified and compared to solutes (Rhodamine WT dye) using energy losses, residence time distributions (RTDs), and mixing models within surcharging and overflowing manholes. The bulk mass of solute and PE concentrations followed similar flow paths across all conditions except for 17.3 ± 7.9 % of PE mass that was immobilized in a dead zone above the inlet pipe for manholes with a surcharge to pipe diameter ratio ≥2. Consequently, these microplastics only exit after a significant change in hydraulic regime occurs, causing microplastics to be at risk of being contaminated over a prolonged duration. No significant mixing differences for PE and solutes were found between manhole geometries. The deconvolution method outperformed the ADZ model with goodness of fit (Rt2) values of 0.99 (0.60) and 1.00 (0.89) for PE and solute mixing, respectively. This establishes the deconvolution method as the most accurate and appropriate model to accurately predict microplastic mixing in manholes and urban drainage systems.

Different Experimental and Numerical Models to Analyse Emptying Processes in Pressurised Pipes with Trapped Air

In hydraulic engineering, some researchers have developed different mathematical and numerical tools for a better understanding of the physical interaction between water flow in pipes with trapped air during emptying processes, where they have made contributions on the use of simple and complex models in different application cases. In this article, a comparative study of different experimental and numerical models existing in the literature for the analysis of trapped air in pressurised pipelines subjected to different scenarios of emptying processes is presented, where different authors have develope, experimental, one-dimensional mathematical and complex computational fluid dynamics (CFD) models (two-dimensional and three-dimensional) to understand the level of applicability of these models in different hydraulic scenarios, from the physical and computational point of view. In general, experimental, mathematical and CFD models had maximum Reynolds numbers ranging from 2670 to 20,467, and it was possible to identify that the mathematical models offered relevant numerical information in a short simulation time on the order of seconds. However, there are restrictions to visualise some complex hydraulic and thermodynamic phenomena that CFD models are able to illustrate in detail with a numerical resolution similar to the mathematical models, and these require simulation times of hours or days. From this research, it was concluded that the knowledge of the information offered by the different models can be useful to hydraulic engineers to identify physical and numerical elements present in the air–water interaction and computational conditions necessary for the development of models that help decision-making in the field of hydraulics of pressurised pipelines.

Fundamentals of Climatology for Engineers: Lecture Note

The study of climatology serves as a foundation for students who wish to specialize in water resources, hydrology, or environmental engineering. Climatology is the study of long-term average weather patterns. It is a distinct field of study from meteorology and is subdivided into a number of subfields. In order to predict the future hydrologic and hydraulic scenarios, knowledge of climatology is essential. In other words, climatology allows us to determine the likelihood of snowfall and hail, the amount of solar thermal radiation that can reach a specific location, etc. Climatology focuses frequently on how the climate has changed over time and how these changes have affected people and events. The primary objective of this technical note is to acquaint and encourage engineers with the basics of the climate and its processes so that they can understand the climatic impact on water resource systems as beginners.

Investigation of Energy Dissipation Rate of Stepped Vertical Overfall (SVO) Spillway Using Physical Modeling and Soft Computing Techniques

In the present study a physical model of a stepped vertical overfall (SVO) spillway is proposed and designed as a novel combination of a free overfall spillway with horizontal steps. First, the hydraulic design characteristics of the proposed spillway were discussed using a laboratory-scaled model. Effective parameters on the energy dissipation rate were defined as the relative critical depth, Froude number, number of steps, and dimensionless steps' geometry parameter using dimensional analysis. The energy dissipation rate of the stepped vertical overfall spillway is measured using a waterwheel laboratory setup. Different geometry and hydraulic scenarios were used to assess the energy dissipation rate variation of the proposed spillway. Furthermore, Support Vector Regression and Random Forest Regression methods were used to estimate the energy dissipation of the proposed structure. Investigating the energy dissipation rate of 27 geometry scenarios with the available range of discharge revealed that the energy dissipation rate against the water's relative depth inside the SVO spillway follows a gradually increasing trend ranging between 88.53% to 98.06%. Also, random forest regression algorithm showed more accurate prediction performance than support vector regression approach with RMSE = 0.128 and R2 = 0.99 in training stage and RMSE = 0.115 and R2 = 0.99 in testing stage. The support vector regression model estimated the proposed spillway's energy dissipation rate with an accuracy of RMSE = 0.67 and R2 = 0.88 in training stage and RMSE = 0.61 and R2 = 0.9 in testing stage.

Optimal Sensor Placement in Hydraulic Conduit Networks: A State-Space Approach

Conduit bursts or leakages present an ongoing problem for hydraulic fluid transport grids, such as oil or water conduit networks. Better monitoring allows for easier identification of burst sites and faster response strategies but heavily relies on sufficient insight in the network’s dynamics, obtained from real-time flow and pressure sensor data. This paper presents a linearized state-space model of hydraulic networks suited for optimal sensor placement. Observability Gramians are used to identify the optimal sensor configuration by maximizing the output energy of network states. This approach does not rely on model simulation of hydraulic burst scenarios or on burst sensitivity matrices, but, instead, it determines optimal sensor placement solely from the model structure, taking into account the pressure dynamics and hydraulics of the network. For a good understanding of the method, it is illustrated by two small water distribution networks. The results show that the best sensor locations for these networks can be accurately determined and explained. A third example is added to demonstrate our method to a more realistic case.

Performance evaluation of potential inland flood management options through a three-way linked hydrodynamic modelling framework for a coastal urban watershed

Abstract 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.

Drones, hydraulics, and climate change: Inferring barriers to steelhead spawning migrations

AbstractGlobal climate models suggest dramatic changes in the timing and form of future precipitation in the Pacific Northwest, United States. By some estimates, in the Columbia River drainage, basin‐wide snow‐water equivalencies could decrease by more than 50% before the end of the century, with locally more extreme variation. In the South Fork Clearwater River, Idaho, where hydraulic barriers are currently thought to partially limit ESA‐listed steelhead migrations, changes in precipitation that could exacerbate the intensity and timing of hydraulic barriers presents an obvious conservation concern. Evidence indicates that the strongest steelhead swimmers are capable of sustaining burst speeds for up to 20 s, with maximum speed being a function of fish size (length). Understanding hydraulic dynamics that have implications for migrating fish requires integration of high‐resolution hydraulic models with sufficient resolution to characterize the hydraulic experience of the fish. Unmanned aerial vehicles (drones) have recently emerged as useful platforms for measuring river ecosystems with high precision. Results from habitat surveys and hydraulic modeling can identify locations where intense hydraulic energy may preclude fish passage during critical migration periods. The current as well as future range of discharges can be evaluated with a spatially explicit hydraulic model to quantify when, where, and how long barriers to migration exist. Further, this approach provides a powerful tool for manipulating the digital physical channel form and presents a heuristic opportunity to test hydraulic scenarios to improve migration success.This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Water and Life > Stresses and Pressures on Ecosystems Water and Life > Methods

Using High-Density LiDAR Data and 2D Streamflow Hydraulic Modeling to Improve Urban Flood Hazard Maps: A HEC-RAS Multi-Scenario Approach

The ability to extract streamflow hydraulic settings using geoinformatic techniques, especially in high populated territories like urban and peri-urban areas, is an important aspect of any disaster management plan and flood mitigation effort. 1D and 2D hydraulic models, generated based on DEMs with high accuracy (e.g., Light Detection and Ranging (LiDAR)) and processed in geographic information systems (GIS) modeling software (e.g., HEC-RAS), can improve urban flood hazard maps. In this study, we present a small-scale conceptual approach using HEC-RAS multi-scenario methodology based on remote sensing (RS), LiDAR data, and 2D hydraulic modeling for the urban and peri-urban area of Bacău City (Bistriţa River, NE Romania). In order to test the flood mitigation capacity of Bacău 1 reservoir (rB1) and Bacău 2 reservoir (rB2), four 2D streamflow hydraulic scenarios (s1–s4) based on average discharge and calculated discharge (s1–s4) data for rB1 spillway gate (Sw1) and for its hydro-power plant (H-pp) were computed. Compared with the large-scale flood hazard data provided by regional authorities, the 2D HEC-RAS multi-scenario provided a more realistic perspective about the possible flood threats in the study area and has shown to be a valuable asset in the improvement process of the official flood hazard maps.

Numerical assessment of temperature effects on concrete failure behavior

This work focuses on the evaluation of temperature effects on concrete failure behavior and modes by means of a realistic thermodynamically consistent non-local poroplastic constitutive model, previously developed by the authors, which is modified in this work. In this regard, two original contributions are presented and discussed. Firstly, and based on significant published experimental results related to this very complex aspect such as the effects of temperature in concrete failure, a temperature dependent non-associated flow rule is introduced to the poroplastic constitutive model to more accurately account for the temperature dependent inelastic volumetric behavior of concrete in post-peak regime. This is crucial for improving overall model accuracy, particularly regarding the temperature effects on concrete released energy during degradation processes. Secondly, and more importantly, the explicit solution of the localization condition in terms of the critical hardening modulus is developed regarding the non-local poroplastic constitutive model reformulated in this work, which allows the analysis of localized failure modes in the form of discontinuous bifurcation of quasi-brittle porous materials like concrete under different temperature, hydraulic and stress state scenarios. Also numerical procedures are followed, which also allow the evaluation of temperature effects on the critical directions for localized failure or cracking which is performed in this work for a wide spectrum of stress states and temperatures. Both, undrained and drained hydraulic conditions are evaluated. The results in this work demonstrate the soundness of the proposed constitutive model modifications and of the derived explicit solution for the critical hardening modulus to accurately predict the temperature effects on both, concrete volumetric behavior, and on the failure modes and related critical cracking direction. They also demonstrate that concrete failure mode and critical localization directions are highly sensitive to temperature, particularly in the compressive regime.

Experimental studies on high-pressure high-temperature contact-condensation at falling jets in the TOPFLOW pressure-tank

Abstract We report on generic experimental studies dealing with the direct contact condensation of steam at a falling sub-cooled water jet at high pressure and temperature. This generic problem concerns some safety-relevant thermal hydraulic scenarios in light water reactors. One of such is the question for heat transfer and mixing when a sub-cooled jet of water in an emergency core-cooling scenario enters a hot pressurized component of the primary reactor circuit. The involved phenomena of heat transfer are complex in this case, reaching from direct condensation of steam via steam bubble entrainment to single phase mixing of hot and cold water. Experiments were performed in the TOPFLOW pressure tank, which is an experimental facility for high-pressure thermal hydraulics experiments in pressure equilibrium. The facility has been designed for studying steam-water two-phase flows at pressures of up to 50 bar. It enables to run experiments in flow domains of complex shape without high difference pressures across the wall. The concept therefore allows us to use thin metal walls and even glass windows to observe flows in complex geometry domains with the help of video camera and to considerably reduce cost and complexity of experimental installations. The experimental results show, that high ambient pressure promotes the direct contact condensation heat transfer of subcooled jet flow heavily.

Modeling of subsurface agricultural drainage using two hydrological models with different conceptual approaches as well as dimensions and spatial scales

In regions where soils are seasonally or perennially wet, subsurface drainage represents an essential water management practice. Two hydrological models with different modeling approaches as well as different dimensional and spatial scales, DRAINMOD (1D, lumped and field-scale) and CATHY (3D, spatially distributed and watershed-scale), were compared in terms of their performance to predict tile-drain flow and to simulate evapotranspiration (ET) under field conditions. Two metrics were defined to assess the capacity of the models to represent the soil water dynamics: relative errors in simulating peak flow and drainage volume. Using different hydraulic conductivity scenarios, both models provided similar results. For the total predicted/observed tile-drain flow comparison, the two models yielded very similar results. In terms of coefficient of determination (R2) and Nash–Sutcliffe model efficiency (NSE), their performances were low in simulating tile-drain flows for dry periods (low observed tile-drain flow). During periods with higher observed tile-drain flow, the performance of both models was good (R2 > 0.75 and NSE mostly > 0.60), but DRAINMOD produced better results than CATHY did. The two models had similar ET values (R2 > 0.80). Regarding the impact of the hydraulic conductivity of each soil layer on subsurface drainage outflow, this study showed that the soil layer below the tile-drain system was the most influential for the two models.

Risk reduction measures: adaptation and integration of the concept into risk analysis of flood protection systems

Risk analysis methods are now widely used to inform and help flood protection system managers in their decision making. Identification and characterisation of risk reduction measures are among the main purposes of the risk analysis process. The risk reduction measure concept, which has first been defined for industrial applications, is now classically used in dams risk analysis. However, due to the specificities of levee systems, the definition of risk reduction measures still needs to be adapted to suit well to risk analysis of flood protection systems. The paper presents an adaptation of the risk reduction measure definition to flood protection system specificities. It details the different types of risk reduction measures that can be applied to levee systems and explains how they can be characterized to evaluate their performance. Finally, the paper presents a process to identify risk reduction measures and integrate them in the specific failure mode and effects analysis method developed by Irstea these past few years to analyse the failures of levee systems and identify the different hydraulic and structural failure scenarios of flood protection systems.