Knowledge and management of aquatic ecosystems (formerly Bulletin Français de la Pèche et de la Pisciculture), an international journal on freshwater ecosystem

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.

Walking underwater reduces joint impacts, enhances stability and lowers the net body weight of the patient during rehabilitation. It is a recent rehabilitation method and few suitable methods exist to study underwater gait kinematics. We propose an underwater inertial measurement (IMU) system analogous to those used in land-based rehabilitation to investigate gait kinematics. The objective of this study was to test and validate the proposed system in two human trials by evaluating the knee angle during the gait. In the first trial, a three-way performance analysis was carried out between the IMU, optoelectronic and motion-capture systems in a traditional rehabilitation setting on land. In the second trial, the proposed underwater IMU is compared with camera-based motion-capture both inside and outside the water environment, using the same subjects in both phases of the trial. This allows for an evaluation of the walking gait in air and underwater as well as a cross-comparison of IMU-based knee angle estimates before and after Gaussian Process Regression. The major finding of this work is that the proposed underwater wearable IMU system provides reliable and repeatable measurements of the knee angle during the gait, both in air and underwater.