Publications de Giovanni De Cesare

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The dynamic of fine sediment in rivers is closely related to the interactions between fine particles, the riverbed and the flow conditions. The accumulation of fine sediment in the riverbed reduces vertical water exchanges and can have detrimental effects ...

Reservoir sedimentation by turbidity currents All lakes created on natural rivers are subjected to reservoir sedimentation. The construction of a dam significantly modifies the flow conditions of natural streams inside and downstream of an artificial lake. Considering the sediment concentration, often high during the flood season, the entering flow shows a greater density than the ambient fluid. Suspended load can therefore be entrained along the reservoir bottom all the way down to the dam in the form of t

Turbulences in liquids caused by jets can be of interest for numerous applications. For one, it concerns flood spillway structures within civil engineering but also is key in any area where turbulent mixing is present. The numerical simulations of jets tha ...

Water diversions from rivers and torrents for anthropic uses of the resource alter the natural flow regime. As a measure, environmental flows have been prescribed and often are enforced by law to follow policies (e.g., minimal flow, proportional redistribu ...

Orifices have been largely studied either for flow metering or for producing head losses. An orifice which is used as a flow meter is well defined in ISO 5167. All the geometrical parameters are defined to obtain discharges as accurate as possible. However ...

In this study, we present the deep learning image segmentation model for drone-based grain size analysis of gravel bars called GALET. The objectives are to quantify the performance of the code and to test its applicability in river research and management. ...

Many run-of-river hydropower plants built without stilling basins now experience progressive scour due to prolonged operation and increasingly frequent floods. The Chancy-Pougny dam on the Rhône River, constructed in the 1920s at the Swiss-French border, exemplifies this issue. Severe flow recirculation was identified as the main cause of erosion, with pressure fluctuations increasing between the original and current stilling basin. While earlier work developed scour protection measures through physical mod

Many run-of-river hydropower plants built without stilling basins now experience progressive scour due to prolonged operation and increasingly frequent floods. The Chancy-Pougny dam on the Rhône River, constructed in the 1920s at the Swiss–French border, exemplifies this issue. Severe flow recirculation was identified as the main cause of erosion, with pressure fluctuations increasing between the original and current stilling basin. While earlier work developed scour protection measures through physical mod

Hydrological, water technological, managerial and human induced processes affect aquatic, amphibian and terrestrial organisms and their habitats, far beyond the main channel of a river. This Riverscape includes diverse riparian habitats which vary in space ...

Sudden starting and stopping of turbines and pumps lead to highly unsteady flow in tailrace channels of hydropower plants (HPP). Submergence of Pelton turbines and air entrainment in pumps due to surge waves must be avoided by technical measures. The exist ...

Reservoir sedimentation is, at present, one of the main concerns in the operational management of dams in the Alps. For larger seasonal storage reservoirs, the main operational concern is the blockage of bottom outlets and turbine abrasion. In case of infr ...

Turbidity currents are the main source of suspended sediment transport in reservoirs and thus one of the main causes of sedimentation. One of the techniques used to avoid reservoir sedimentation is through venting of turbidity currents. In the framework of ...

The Swiss utility Kraftwerke Oberhasli AG (KWO) currently implements "KWO plus", an upgrading program involving a large number of economical and ecological improvements of their hydropower schemes. A major project, the modification of the Handeck 2 power plant intake, requires total emptying of the Räterichsboden reservoir having an active volume of 25 million m3. In order to define the most efficient and ecological emptying process for these circumstances, KWO commissioned a hybrid modelling program of the

Ultrasonic velocimetry based on the Doppler shift effect accurately provides quasi-instantaneous flow fields for fluids with a sufficiently high acoustic scattering level. However, ultrasonic velocity instruments are known to perform poorly in clear water ...

Freshwater ecosystems face increasing threats from human activities and climate change, thus requiring efforts to reduce impacts and prevent further deterioration. Restoration projects for riverine environments often rely on hydraulic, habitat, and metapop ...

The river inflow in a natural lake with important suspended sediment load during floods, can impact water quality by mobilizing dissolved matters like phosphorous from deep to surface waters. Generally due to thermal stratification in prealpine lakes, the ...

The 130 m high Ilarion Dam is built on the Aliakmon River in northern Greece. Its two spillways are equipped with ski jumps to deflect high-velocity jets towards the centre of the plunge pool. Significant scouring occurred in the pool during two major floo ...

In pumped-storage reservoirs, turbulent kinetic energy input from plant operation can be considerably high. Flow velocities were measured by Acoustic Doppler Current Profilers near the intake/outlet structure to describe flow patterns induced by pumped-sto ...

Water reservoirs used to produce electricity have an impact on the environment and durability by : • stopping the natural sediment flux • changing the flow regime downstream of the reservoirs • storing (fine) sediments that reduce the storage volume Those 3 issues have been leading to the development of strategies in order to improve the equilibrium of the ecosystem downstream such structures, with solution such as sediment flushing and simple water flushing reproducing flood events. Those operations produc

Rivers extend beyond the channels that are typically associated with this word. Of particular interest are flood plains, where important hydro- and morphodynamic processes occur as a result of recurrent flooding. Ecologically, they also support the establi ...

Giovanni De Cesare

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Influence of the shear stress on fine sediment exchanges with the substrate using UVP measurements

Alluvionnement des retenues par courants de turbidité

Modelling of plunge pool scour evolution in non-cohesive sediments

Dynamic environmental flows using hydrodynamic-based solutions for sustainable hydropower

Head losses and influence length of sharp-edged and rounded orifices under steady flow conditions

GALET: A deep learning image segmentation model for drone-based grain size analysis of gravel bars

Mitigating scour in aging run-of-river hydropower infrastructure: an analysis of pressure fluctuations in the physical model of Chancy-Pougny (Switzerland)

MITIGATING SCOUR IN AGING RUN-OF-RIVER HYDROPOWER INFRASTRUCTURE: AN ANALYSIS OF PRESSURE FLUCTUATIONS IN THE PHYSICAL MODEL OF CHANCY-POUGNY (SWITZERLAND)

Fulfilling Riverscape – a creative interdisciplinary approach

Surge Wave Propagation in a Common Tailrace Channel for Two Large Pumped-Storage Plants

Evolution of reservoir flushing and emptying practices in a cascade of large reservoirs across several decades

Velocity profiles of turbidity currents flowing over a flat bed

Hybrid modeling of sediment management during drawdown of Räterichsboden reservoir

Use of gas bubbles for ultrasound Doppler flow velocity profile measurement

Hydraulic drive framework on habitat suitability enhances movement bias of brown trout in stream networks

Circulation in stratified lakes due to flood-induced turbidity currents

Plunge pool scour and bank erosion: assessment of protection measures for Ilarion dam by physical and numerical modelling

Flow field in a reservoir subject to pumped-storage operation - in situ measurement and numerical modeling

Sediment flushing downstream dams: a study on the clogging by fine sediments

Simulation of fine sediment deposition on floodplains