Evaluation of the flow resistance in mobile bed vegetated rivers

River hydrodynamicsBed roughness and flow resistanc

An Integrated Modeling Approach to Optimize the Management of a Water Distribution System: Improving the Sustainability While Dealing with Water Loss, Energy Consumption and Environmental Impacts

Research article There is a strong link between water and energy in municipal water systems then the Alliance to Save Energy coined the term "Watergy" [1]. Each component of the integrated water system contributes differently to the energy balance. With regard to urban water distribution systems (WDS), the pumping energy cost represents the single largest part of the total operational cost, also magnified by every litre of water lost to leaks. Even a small increase in operational efficiency may result in significant cost savings to the water industries. Therefore the inefficient management of water distribution systems results not only into depletion of water resources but also into energy consumption that increase CO2 emissions related also to the treatment of water volumes greater than needed, with use of excessive chemical components and consequent higher environmental global impact. The research outlined in this contribution was born with the aim to develop appropriate methodologies and tools to support the optimization of the WDS performance, in terms of water saving and reduction of energy consumptions and consequently environmental impacts. The integration of advanced WDS hydraulic modelling with a material and energy flow analysis is proposed herein, where the output of the hydraulic simulations permits to get more accurate input for a metabolic analysis of the system Next phases of this research will test the integrated model under different scenarios, aimed at quantifying the environmental impact of different WDS management solutions by means of selected indicator

Isotopic characterization of groundwater for drinking use in multilayer aquifers of the Milano and Monza provinces

Groundwater, drinking water, isotopes, EU directives, hydrogeolog

Multi-isotopic regional-scale screening on drinking groundwater in Lombardy Region (Italy)

Groundwater represents the main and safest source of water that supply, for drinking purposes, numerous urban and rural communities all over the world. A deep knowledge of aquifer systems in terms of quality, vulnerability and renewability is fundamental to preserve groundwater resources. Thanks to the contribution of different members of Water Alliance in synergy with Sapienza University, during November 2019 a multi-isotopic analysis at regional scale on groundwater tapped for drinking purposes in a wide area of Lombardy Region, has been carried out. The study aimed to improve knowledge about recharge mechanisms, groundwater relative age and impact of human activities on groundwater quality Each Water Alliance supplier selected wells and springs for a total of 121 samples, catching different aquifer groups and distributed from North to South. Groundwater stable isotope analyses were performed on all the monitoring points, instead tritium, nitrogen isotopes (15N and 18O in nitrates), sulphate isotopes (34S and18O) and 13C isotope in Dissolved Inorganic Carbon (DIC), were analysed in selected monitoring wells basing on previous data and major ions concentrations results. Therefore, results confirmed the key role of multi-isotopic approach in defining aquifer recharge processes, relative groundwater age and origin of pollutants, offering a useful tool to point out local issues which can be deeply investigated by each water supplier

A scoping review of scientific concepts concerning motor recovery after stroke as employed in clinical trials

The scientific literature on poststroke rehabilitation is remarkably vast. Over the last decades, dozens of rehabilitation approaches have been investigated. However, sometimes it is challenging to trace new experimental interventions back to some of the known models of motor control and sensorimotor learning. This scoping review aimed to investigate motor control models' diffusion among the literature on motor recovery after stroke. We performed a literature search on Medline, Cochrane, Web of Science, Embase, and Scopus databases. The last search was conducted in September 2023. This scoping review included full-text articles published in English in peer-reviewed journals that provided rehabilitation interventions based on motor control or motor learning frameworks for at least one individual with stroke. For each study, we identified the theoretical framework the authors used to design the experimental treatment. To this aim, we used a previously proposed classification of the known models of motor control, dividing them into the following categories: neuroanatomy, robotics, self-organization, and ecological context. In total, 2,185 studies were originally considered in this scoping review. After the screening process, we included and analyzed 45 studies: 20 studies were randomized controlled trials, 12 were case series, 4 were case reports, 8 were observational longitudinal pilot studies, and 1 was an uncontrolled trial. Only 10 studies explicitly declared the reference theoretical model. Considering their classification, 21 studies referred to the robotics motor control model, 12 to the self-organization model, 8 to the neuroanatomy model, and 4 to the ecological model. Our results showed that most of the rehabilitative interventions purposed in stroke rehabilitation have no clear theoretical bases on motor control and motor learning models. We suggest this is an issue that deserves attention when designing new experimental interventions in stroke rehabilitation

The extension of EPANET source code to simulate unsteady flow in water distribution networks with variable head tanks

This paper describes the modifications applied to EPANET, a public-domain water distribution system modelling software package, that does not correctly compute the hydraulics of a water distribution network (WDN) with variable tank heads in (slow) unsteady flow conditions. Firstly the methodology adopted to extend the Global Gradient Algorithm (GGA) implemented in the original EPANET source code to the Extended Period Simulation-GGA (EPS-GGA) is described. Then the convergence and stability conditions of the theta method, used for the discretisation in time of the set of differential equations describing the hydraulic behaviour of a WDN, are discussed. The reasons for EPS-GGA numerical stability are demonstrated and a fully implicit discretisation of differential equations (i.e. theta = 1) is suggested as the optimal choice as implicitly proposed in Giustolisi et al. but without theoretical justification. Both the modified and original versions of EPANET are applied to a particularly severe test case of a WDN. Moreover, the procedures for the correct numerical representation of the tanks' maximum and minimum level boundary conditions are developed and compared with previously proposed procedures. The modified version of EPANET source code does not show the significant instabilities which are evident in the original version, nor the lack of consistency due to the improper maximum and minimum level boundary condition schematisations formerly proposed in the scientific literature

Design criteria for a type of asymmetric orifice in a surge tank using CFD

An asymmetric orifice can be added to a surge tank of a hydro power plant to dampen the mass oscillation. This allows a reduction of the required volume and a more stable behavior of the overall hydraulic system. In this paper, the advantage of a typical asymmetric orifice is shown in comparison with a sharp-edged geometry with two different pipe diameters. The software ANSYS-CFX is used to investigate the influence of the individual geometry parameters (radius, length, angle at the forefront) on the local head loss coefficients and the ratio of the two flow directions. Furthermore, a coefficient is analyzed based on an equation from the literature for the sharp-edged structure, which can be used comparably for the asymmetric orifice. This allows us to reach preliminary assumptions of the losses at an early state of the design process. The following adaptation can be supported by the presented guidance for the optimization process, so that a suitable geometry for the specific boundary conditions can be found

Basin-scale hydrogeological, geophysical, geochemical and isotopic characterization: an essential tool for building a Decision Support System for the sustainable management of alluvial aquifer systems within the provinces of Milan and Monza-Brianza (Northern Italy)

CAP Group is a public company, supplying the municipalities within the provinces of Milan and Monza/Brianza (Northern Italy) with the integrated water service: 197 municipalities and more than 2 million users served, 887 wells, 154 wall-mounted tanks and hubs, a water supply network of over 7500 km, from which approximately 250 million cubic metres of water per year are withdrawn. The drinking water supply comes exclusively from groundwater resources, circulating in several overlapping aquifer systems. Basin-scale water resource management, as required by the European Water Framework Directive (2000/60/EC), is an extremely complex task. In view of this backdrop, CAP is currently developing a project called Infrastructural Aqueduct Plan that relies on a Decision Support System approach. The paper describes the preliminary steps concerning the design of a prototype Decision Support System aiming at the management of groundwater resources on a basin scale (Ticino and Adda rivers area). CAP Group Decision Support System is intended to be a package allowing for water resource assessment, identification of boundary conditions, climatic driving forces and demographic pressures, simulation and investigation of future forecasts and comparison of alternative policy measures. The project has been designed in steps including Geodatabase building, geographic information system (GIS) analysis (including multilayer analysis) and numerical modelling. The data collected in the geodatabase were analyzed to design GIS quantitative and qualitative thematic maps in order to perform the multilayer analysis of current and future state and impacts, for providing the decision maker with a comprehensive picture of the water system. The multilayer analysis relies on specific indicators based on some quantitative and qualitative data: hydrogeological, chemical, isotopic, soil use and hazards, climatic and demographic. Each parameter belonging to these macro areas were classified by 7-criticality classes scale and weights were assigned to each of them. For each macro area a synthetic index was calculated by multiplying class values with weights. These synthetic indexes were managed with a multilayer approach and compared with other models and tools (e.g. geological model, numerical groundwater model, distribution network model) in order to obtain criticality indexes. The assessment of these criticality indexes allow to evaluate alternative and strategic solutions to achieve a more efficient and sustainable water system management using a best choice approach. Currently the project team is working on multilayer analysis. The next task will be the implementation of groundwater numerical model

Tuning ANN Hyperparameters for Forecasting Drinking Water Demand

The evolution of smart water grids leads to new Big Data challenges boosting the development and application of Machine Learning techniques to support efficient and sustainable drinking water management. These powerful techniques rely on hyperparameters making the models’ tuning a tricky and crucial task. We hence propose an insightful analysis of the tuning of Artificial Neural Networks for drinking water demand forecasting. This study focuses on layers and nodes’ hyperparameters fitting of different Neural Network architectures through a grid search method by varying dataset, prediction horizon and set of inputs. In particular, the architectures involved are the Feed Forward Neural Network, the Long Short Term Memory, the Simple Recurrent Neural Network and the Gated Recurrent Unit, while the prediction interval ranges from 1 h to 1 week. To avoid the problem of the Neural Networks tuning stochasticity, we propose the selection of the median model among several repetitions for each hyperparameter’s configurations. The proposed iterative tuning procedure highlights the change of the required number of layers and nodes depending on Neural Network architectures, prediction horizon and dataset. Significant trends and considerations are pointed out to support Neural Network application in drinking water prediction

FORCE schemes on moving unstructured meshes for hyperbolic systems

The aim of this paper is to propose a new simple and robust numerical flux of the centered type in the context of Arbitrary-Lagrangian–Eulerian (ALE) finite volume schemes. The work relies on the FORCE flux of Toro and Billet and is concerned with the solution of general hyperbolic systems of nonlinear equations involving both conservative and non-conservative terms as well as sources which might become stiff. The proposed approach is formulated in a general way using a path-conservative method and the Roe-type system matrix is computed numerically in order to provide a numerical flux function that can be applied to any given hyperbolic system. Furthermore, one great advantage of the FORCE flux is that no information about the eigenstructure of the system is needed, not even eigenvalues, but only information regarding the geometry of the control volumes are required, which are automatically available in the moving mesh framework. Our method is of the finite volume type, high order accurate in space, thanks to a WENO reconstruction operator, and even in time, due to a fully-discrete ADER one-step discretization. The algorithm applies to moving multidimensional unstructured meshes composed by triangles and tetrahedra. Both accuracy and robustness of the scheme are assessed on a series of test problems for the Euler equations of compressible gas dynamics, for the magnetohydrodynamics equations as well as for the Baer–Nunziato model of compressible multi-phase flows