Digitalization and real-time control to mitigate environmental impacts along rivers: Focus on artificial barriers, hydropower systems and European priorities

Hydropower globally represents the main source of renewable energy, and provides several benefits, e.g., water storage and flexibility; on the other hand, it may cause significant impacts on the environment. Hence sustainable hydropower needs to achieve a balance between electricity generation, impacts on ecosystems and benefits on society, supporting the achievement of the Green Deal targets. The implementation of digital, information, communication and control (DICC) technologies is emerging as an effective strategy to support such a trade-off, especially in the European Union (EU), fostering both the green and the digital transitions. In this study, we show how DICC can foster the environmental integration of hydropower into the Earth spheres, with focus on the hydrosphere (e.g., on water quality and quantity, hydropeaking mitigation, environmental flow control), biosphere (e.g., improvement of riparian vegetation, fish habitat and migration), atmosphere (reduction of methane emissions and evaporation from reservoirs), lithosphere (better sediment management, reduction of seepages), and on the anthroposphere (e.g., reduction of pollution associated to combined sewer overflows, chemicals, plastics and microplastics). With reference to the abovementioned Earth spheres, the main DICC applications, case studies, challenges, Technology Readiness Level (TRL), benefits and limitations, and transversal benefits for energy generation and predictive Operation and Maintenance (O&M), are discussed. The priorities for the European Union are highlighted. Although the paper focuses primarly on hydropower, analogous considerations are valid for any artificial barrier, water reservoir and civil structure which interferes with freshwater systems.Digitalization and real-time control to mitigate environmental impacts along rivers: Focus on artificial barriers, hydropower systems and European prioritiespublishedVersio

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Validation of a Swimming Direction Model for the Downstream Migration of Atlantic Salmon Smolts

Fish swimming performance is strongly influenced by flow hydrodynamics, but little is known about the relation between fine-scale fish movements and hydrodynamics based on in-situ investigations. In the presented study, we validated the etho-hydraulic fish swimming direction model presented in the River Mandal from Southern Norway, using similar behavioral and hydraulic data on salmon smolts from the River Orkla in Central Norway. The re-parametrized model explained the variation of the swimming direction of fish in the Orkla system in same degree as the original model performed in the Mandal system (R2: 84% in both cases). The transferability of the model when using it from one river to predict swimming direction in the other river was lower (R2: 21% and 26%), but nevertheless relatively high given that the two localities differed in hydraulic conditions. The analyses thus provide support for the fact that the identified hydraulic parameters and their interaction affected smolt behavior in a similar way at the two sites, but that local parametrization of the base model is required. The developed etho-hydraulic models can provide important insights into fish behavior and fish migration trajectories and can be developed into prediction models important for the future development of behavioral downstream migration solutions

Shelter for juvenile Atlantic salmon: availability and prediction in rivers with and without hydropower regulation.

It is assumed that river regulation in general and hydropeaking in particular, cause elevated degrees of fine sediments in river beds which affect negatively habitat quality for juvenile salmon. Finstad et al. (2007) developed a method to measure interstitial spaces (shelter abundance for fish) in running waters. Shelter availability is a candidate mechanism for the survival of juvenile salmon due to the reduction of predation risk and is influenced by the degree of fines. The first goal of this study is to find better relationship between shelter abundance measured with the method by Finstad et al. (2007), and grain size distribution. This relationship will be based on a dataset by (Jocham, 2010) and own data gathered from the river Gaula in Norway. The second goal of the study is to implement the new relationship into the one-dimensional hydraulic model HEC-RAS, in order to predict the development of shelter over time. Here, two main flow scenarios will be investigated at two river sites, Lundesokna and Nidelva streams from Middle-Norway. As a forerunner before the main simulations, sensibility tests will be run to estimate differences between several empirical sediment transport equations, sorting methods, computational time steps and an extreme flood event s effect on river bed. In the case of main flow scenarios, the first hydrograph consists of an average yearly runoff without the hydropower regulation. The second hydrograph will be in correlation with the yearly energy production of the regulation power company. The comparison at the end of the study contains the main differences between the two type of hydrograph related to chosen and calculated parameters. These variables proved their worth to play key factors in the differentiation between operated and natural type of hydrographs with their effects on river bed morphology. Nevertheless, major differences cannot be observed among the cases, some anomalies are occurred in details, which are going to be explained at the evaluation of the results

Supersaturation in hydropower installations

Gas supersaturation occurs when the amount of dissolved gas in water exceeds the solubility for the given local pressure. Such conditions may happen in natural watercourses, but more observations are associated with hydropower installations in rivers. The main anthropogenic sources either originate from water spilled over dams into deep pools or from air entrained through tunnel systems in hydropower plants. Supersaturated water in rivers have significant ecological consequences to aquatic biota. This report provides a literature review of the available reports and publications regarding supersaturation from hydropower installations. The main focus is on high-head HPPs with secondary intakes, which is the most common source of supersaturation in Norway. This report provides an overview of the physical processes, main sources of supersaturation associated with in hydropower installations and mitigation measure.Supersaturation in hydropower installationspublishedVersio

Supersaturation in hydropower installations

Gas supersaturation occurs when the amount of dissolved gas in water exceeds the solubility for the given local pressure. Such conditions may happen in natural watercourses, but more observations are associated with hydropower installations in rivers. The main anthropogenic sources either originate from water spilled over dams into deep pools or from air entrained through tunnel systems in hydropower plants. Supersaturated water in rivers have significant ecological consequences to aquatic biota. This report provides a literature review of the available reports and publications regarding supersaturation from hydropower installations. The main focus is on high-head HPPs with secondary intakes, which is the most common source of supersaturation in Norway. This report provides an overview of the physical processes, main sources of supersaturation associated with in hydropower installations and mitigation measure.publishedVersio

Application of Three-Dimensional CFD Model to Determination of the Capacity of Existing Tyrolean Intake

CFD models of intakes in high-head hydropower systems are rare due to the lack of geometric data and cost of modeling. This study tests two different types of software to see how modeling can be performed in a cost-effective way with scarce input data and still have sufficient accuracy. The volume of fluid (VoF) model simulations are conducted using both ANSYS Fluent and OpenFOAM. The geometry is modelled from Google Earth satellite images, drone scanning data, and design drawings from the construction period and supported by field observations for extra quality control. From the model, both capacity parameters and flow pattern are calculated. For capacity, the Cd factor is calculated and compared with the literature. The simulations are conducted for a Tyrolean weir with rectangular bars (flat steel) in the rack. Simulated flow patterns through the rack with ANSYS Fluent and OpenFOAM are compared. OpenFOAM simulations yielded 15% to 20% higher water levels compared to the VOF model applied in Ansys Fluent. Also, when the flow rate was high, the water capture capacity calculated with ANSYS Fluent was 10% higher than that obtained with OpenFOAM. However, considering the total simulation times, modeling with OpenFOAM offered approximately 11% faster results