Freshwater ecosystems host a very large fraction of the world’s total biodiversity, but water infrastructures development, growing needs for water use and climate change are causing fast population declines and increased extinction risk for many freshwater organisms.
Balancing the conflicts among the ambitious targets set by the EU Biodiversity Strategy 2030 and those of other EU Directives (Renewable Energy Sources, Flood Directive, etc.) that put additional pressures on freshwater habitats, represents a challenging issue.
Under this scenario, the EU-funded RIBES (RIver flow regulation, fish BEhaviour and Status) project aims at training 15 Early Stage Researchers in the interdisciplinary field of Ecohydraulics to find innovative solutions for freshwater fish protection and river continuity restoration in anthropogenically altered rivers, within a interdisciplinary and intersectoral Network of European Universities, consultancy companies, public agencies and hydropower industry.
The main features of the RIBES project and the significant opportunities offered by the Marie Skłodowska-Curie Doctoral Networks to implement innovative doctoral programmes advancing knowledge in the field of water research, will be presented.

Her contributions to society from her activity carried out in the Fluid Mechanics Area of ​​the University of Zaragoza since 1992, has included aspects of research, teaching and university management. She has participated in 2 Quality Doctorate programs, Fluid Mechanics and Mechanical Engineering. She was a teacher in the Master's Degree in Applied Mechanics at the University of Zaragoza and currently in the Master's Degree in Industrial Engineering. She also was IP of the Computational Fluid Mechanics Group that has been recognized as a Reference Group within the research program of the Government of Aragon. In addition, she has been responsible for a Master's Study in Water Resources Engineering at the University of Zaragoza, for 10 editions.
She has been permanently active in technological development,innovation, outreach activities (4 summer courses on Information and Technological Development for Water Management and 3 International Workshop on Hydrodynamic Modelling) and collaboration with industry and the private sector. She has led agreements with the Ebro Hydrographic Confederation, the Bilbao Water Consortium. She has collaborated in transfer projects with the company Inclam (Spain) and with the company Hydronia (USA) for the registration and transfer of marketable software. They have the registration of 2 utility models at the University of Zaragoza.
Her contributions to the training of young researchers materialize in the direction of 20 PFC, 22 TFG, 6 TFM and 15 doctoral theses that have culminated in the creation of a stable research group (www.ghc.unizar.es) of which she is responsable. These works have been financed with competitive scholarships of which she has been a tutor or through contracts charged to projects of my group (16 doctoral theses directed, 9 in the last 10 years, and 2 more currently in development).

Nowadays, the great power of modern computers combined with well-designed numerical models allows to develop computational models able to deal with simulations of several coupled phenomena over detailed complex topography. An efficient and properly calibrated computational model represents a useful tool to provide insight into the catchment dynamics at hydrological and geomorphological levels. In addition, it allows to develop detailed risk management and conservation plans.
The challenge of finding a compromise between computational time and level of accuracy and robustness has traditionally expanded the use simplified models rather than full two-dimensional (2D) models for flood simulation. This work presents a GPU accelerated 2D shallow water model for the simulation of flood events in real time. In particular, an explicit first-order finite volume scheme is detailed to control the numerical instabilities that are likely to appear when used in complex topography. The model is applied to reproduce real events in a reach of the Ebro River (Spain) in order to compare simulation results with field data in a large domain and long flood duration allowing an analysis of the performance and speed-up achieved by different GPU devices. The high values of fit between observed and simulated results as well as the computational times achieved are encouraging to propose the use of the model as forecasting system.
Morphodynamic transient flows require numerical models that incorporate complex physical relationships. Moreover, the lack of measured data set (either in field or in laboratories) with enough accuracy, precision and resolution, which allow proper calibration and validation of the numerical models, presents an additional drawback. Recent advances in the simulation of shallow flows over mobile bed have shown that accurate and stable results in realistic problems can be provided if an appropriate coupling between the 2D shallow water equations (SWE), the suspended solid load transport equation and the Exner equation is performed. In this way the computational cost may become unaffordable in situations involving large time and space scales. Therefore, for the numerical efficiency recovering, the coupling technique is simplified, not decreasing the number of waves involved in the Riemann problem but simplifying their definitions. Furthermore, special attention has to be paid to limit the time step size of the system in order to avoid numerical instabilities, while computational cost remains suitable. The simplified model is formulated under a general framework able to insert any desirable discharge solid bedload formula. The effects of the approximations made are tested against experimental data which include transient problems over erodible bed in laboratory experiments and realistic rivers. The main issue is the high computational effort required for obtaining accurate numerical solutions due to the high number of cells involved. However, recent advances in massive parallelization techniques for 2D hydraulic models are able to reduce computer times by orders of magnitude making 2D applications competitive and practical for operational flood prediction in large river reaches. In particular, high performance code development can take advantage of general purpose and inexpensive Graphical Processing Units (GPU), allowing to run 2D simulations more than 600 times faster than old generation 2D codes, in some cases.

Predicting the effects of management strategies and interventions on the water quality in catchments, urban drainage, and water distribution systems, requires knowledge of the hydrodynamic processes. These processes cover spatial scales of a few millimetres (turbulence) to several kilometres (catchments), with a similarly large range of timescales from seconds to weeks. Water quality models, whether 1D, 2D or 3D, generally employ solutions to the advection-dispersion equation, which require parameters to describe and integrate all the mixing processes related to the temporal and spatial averaging processes. This presentation will summarise some field and laboratory fluorescent tracer studies which quantify mixing processes in estuaries, river channels, urban drainage structures and pipe flows. These studies cover a range of spatial and temporal scales and investigate the effects of unsteady flow conditions and non-uniform shapes. The overall aim is to improve understanding of the dominant mechanisms and to provide simple numerical descriptions to quantify the mixing processes, for inclusion in water quality models.

Quantifying swimming endurance is key for the design of effective fish passage solutions. Such solutions are urgently needed to restore continuity in rivers where man-made water-infrastructures represent barriers for fish migration and hence a major cause of biodiversity loss in freshwater ecosystems, as reported extensively in the literature. Unfortunately, despite years of research, modelling endurance is still strongly based on weak empirical grounds lacking any theoretically supported framework of analysis. This lecture will present some work that has been recently carried out to bridge this knowledge gap, by a multidisciplinary group of scientists working at the interface between fish biology and fluid mechanics. The aim of the proposed work is to provide evidence that endurance curves pertaining to the anaerobic swimming regime (i.e. the most relevant regime for fishway design), display a universal scaling that is susceptible to theoretical scrutiny. The proposed scaling is derived by combining principles of fish energetics and locomotion and is tested over an extensive dataset that was retrieved from the literature. Results demonstrate that, despite some scatter and some issues related to the heterogeneity of the retrieved dataset, experimental data confirm well theoretical predictions.
A discussion about the practical applications of our results and some perspectives for future research work will be presented in the final part of the seminar.

His research interests include theoretical and computational fluid mechanics and, in particular: turbulence, dispersed two-phase systems and flows with interfaces, combustion, thermomechanics of flows in granular media, inverse design methods, stochastic modelling, Lagrangian particle methods such as Probability / Filtered Density Function (PDF/FDF) and Smoothed Particle Hydrodynamics (SPH), the lattice Boltzmann method (LBM) and large-eddy simulations (LES). His research to date resulted in more than 60 papers published in JCR-listed journals.
He is a member of the Committee on Mechanics of the Polish Academy of Sciences and the chair of the Fluid Mechanics Section there. He serves as Section Editor of Archives of Mechanics and Computer Assisted Methods in Engineering and Science, as well as Editorial Board member of Acta Mechanica.

Environmental applications of multiphase flows include sediment transport and phenomena involving air-water interfaces (dealt with as either free-surface or interfacial multiphase systems). Computational treatment of the latter may involve interface tracking or capturing that remains a challenge for modelling, in particular in the Eulerian approach. Arguably, this is one of the advantages of the Lagrangian particle methods such as Smoothed Particle Hydrodynamics (SPH). The meshless nature of SPH may represent some advantage for fluid-solid interaction problems (such as moving/floating bodies) and for the treatment of complex geometries; however, it is problematic for adaptive refinement or variable resolution in space. Upon the spatial discretisation using interpolation points, or particles, the flow dynamics in SPH is represented by a system of ordinary differential equations for particle's advection and the evolution of carried-on quantities (mass, momentum, phase indicator, etc.).
In this talk, we will present the basic features and problems of SPH in terms of its capacity to describe physical phenomena, the convergence and accuracy of the approach along with its computational complexity, and the numerical implementation issues. We will then present several application cases such as sediment transport, bed scour, free surface flows, flow regime changes in gas-liquid systems. We will also discuss the weaknesses of the approach, and perspectives to overcome them.

Fish sense in the water environment using their lateral line system. It consists of tiny arrays of flexible masts on the outer surface of the body, as well as tunnels within the body surface itself. Understanding how fish sense and respond to flows requires us to interpret them through the lens of their lateral line system. In this talk, the mechanosensory system of freshwater fish is presented, including the physical ranges and speeds at which fish can process flow information. Furthermore, bioinspired fish-shaped probes are introduced which mimic some of the ways fish experience the flow. Novel methods to process and interpret these data to improve fish passage are presented, including a new way to modify velocity data into maps which take into account how the fish’s body modifies the flow field itself. The use of machine learning to identify and classify complex data sets from fish-like sensors is discussed, as well as challenges and new opportunities for ethohydraulic studies in the lab and in the field. Improving fish passage is a major challenge, and will require new and innovative methods to understand and interpret the complex underwater environment inhabited by freshwater fish. The bioinspired devices and data processing methods presented in this talk are the beginning of a promising new and challenging paradigm shift in ecohydraulics: to consider “flow from a fish’s perspective”.