Marty R.,Grenoble Institute of Technology |
Zin I.,Grenoble Institute of Technology |
Obled C.,Grenoble Institute of Technology |
Bontron G.,Compagnie Nationale du Rhone |
Journal of Applied Meteorology and Climatology | Year: 2012
Heavy-rainfall events are common in southern France and frequently result in devastating flash floods. Thus, an appropriate anticipation of future rainfall is required: for early flood warning, at least 12-24 h in advance; for alerting operational services, at least 2-3 days ahead. Precipitation forecasts are generally provided by numerical weather prediction models (NWP), and their associated uncertainty is generally estimated through an ensemble approach. Precipitation forecasts also have to be adapted to hydrological scales. This study describes an alternative approach to commonly used limited-area models. Probabilistic quantitative precipitation forecasts (PQPFs) are provided through an analog sorting technique, which directly links synoptic-scale NWPoutput to catchment-scale rainfall probability distributions. One issue concerns the latest developments in implementing a daily version of this technique into operational conditions. It is shown that the obtained PQPFs depend on the meteorological forecasts used for selecting analogous days and that the method has to be reoptimized when changing the source of synoptic forecasts, because of the NWP output uncertainties. Second, an evaluation of the PQPFs demonstrates that the analog technique performs well for early warning of heavy-rainfall events and provides useful information as potential input to a hydrological ensemble prediction system. It is shown that the obtained daily rainfall distributions can be unreliable. A statistical correction of the observed bias is proposed as a function of the no-rain frequency values, leading to a significant improvement in PQPF sharpness. © 2012 American Meteorological Society.
Mansanarez V.,IRSTEA |
Le Coz J.,IRSTEA |
Renard B.,IRSTEA |
Lang M.,IRSTEA |
And 2 more authors.
Water Resources Research | Year: 2016
Stage-fall-discharge (SFD) rating curves are traditionally used to compute streamflow records at sites where the energy slope of the flow is variable due to variable backwater effects. We introduce a model with hydraulically interpretable parameters for estimating SFD rating curves and their uncertainties. Conventional power functions for channel and section controls are used. The transition to a backwater-affected channel control is computed based on a continuity condition, solved either analytically or numerically. The practical use of the method is demonstrated with two real twin-gauge stations, the Rhône River at Valence, France, and the Guthusbekken stream at station 0003⋅0033, Norway. Those stations are typical of a channel control and a section control, respectively, when backwater-unaffected conditions apply. The performance of the method is investigated through sensitivity analysis to prior information on controls and to observations (i.e., available gaugings) for the station of Valence. These analyses suggest that precisely identifying SFD rating curves requires adapted gauging strategy and/or informative priors. The Madeira River, one of the largest tributaries of the Amazon, provides a challenging case typical of large, flat, tropical river networks where bed roughness can also be variable in addition to slope. In this case, the difference in staff gauge reference levels must be estimated as another uncertain parameter of the SFD model. The proposed Bayesian method is a valuable alternative solution to the graphical and empirical techniques still proposed in hydrometry guidance and standards. © 2016. American Geophysical Union. All Rights Reserved.
Guertault L.,IRSTEA |
Camenen B.,IRSTEA |
Peteuil C.,Compagnie Nationale du Rhone |
Advances in Geosciences | Year: 2014
An analysis of the long term morphological evolution of the Génissiat reservoir (France) is provided. First, a methodology for bathymetric data processing and reservoir sediment volume budget calculation is described. An estimation of global uncertainties in volume calculation is proposed. The reservoir bathymetric budget for several dam flushing events and interflush periods is presented, showing the global decrease of deposited sediment volume with time. The spatial dynamics of the reservoir subreaches is highlighted and typical patterns in flush and interflush periods are identified. © 2014 Author (s).
Jean-Baptiste N.,IRSTEA |
Malaterre P.-O.,IRSTEA |
Doree C.,Compagnie Nationale du Rhone |
Sau J.,CNRS Fluid Mechanics and Acoustics Laboratory
Mathematics and Computers in Simulation | Year: 2011
Water management, in a variety of contexts and objectives, is a very important issue gaining increasing attention worldwide. In some places and during some periods, this is due to the scarcity of the water resource, and increasing competition for its use. In some others, it can be risk reduction due to flood events, or optimization of hydropower production along rivers. Hydraulic modeling, system analysis and automatic control are now parts of most water management projects. In order to operate hydraulic devices on irrigation canals or rivers, detailed information on the hydraulic state of the system must be available. This is particularly true when the control algorithms are based on Linear Quadratic Gaussian or Predictive Control approaches, using full state space models. Usually, the only known quantities are water levels, measured at limited locations. Sometimes, the discharge is known at specific locations (cross devices with gates, weirs, or hydropower turbines). The design of an observer is a very useful tool for reconstructing unmeasured data, such as discharges or water levels at other locations, unknown perturbations, such as inflows or outflows, and model parameters such as Manning-Strickler or hydraulic device discharge coefficients. Several approaches are able to provide such observers. The paper illustrates and compares the use of sequential Kalman Filter and sequential Particle Filter State Observer on these water management problems. Four scenarios have been selected to test the filters, based on twin experiences or using real field data. Both approaches proved to be efficient and robust. The Kalman Filter is very fast in terms of calculation time and convergence. The Particle Filter can handle the non-linear features of the model. © 2010 IMACS.
Le Coz J.,IRSTEA |
Hauet A.,Électricité de France |
Pierrefeu G.,Compagnie Nationale du Rhone |
Dramais G.,IRSTEA |
Journal of Hydrology | Year: 2010
Flash-floods that occur in Mediterranean regions result in significant casualties and economic impacts. Remote image-based techniques such as Large-Scale Particle Image Velocimetry (LSPIV) offer an opportunity to improve the accuracy of flow rate measurements during such events, by measuring the surface flow velocities. During recent floods of the Ardèche river, LSPIV performance tests were conducted at the Sauze-Saint Martin gauging station without adding tracers. The rating curve is well documented, with gauged discharge ranging from 4.8m 3s -1 to 2700m 3s -1, i.e., mean velocity from 0.02ms -1 to 2.9ms -1. Mobile LSPIV measurements were carried out using a telescopic mast with a remotely-controlled platform equipped with a video camera. Also, LSPIV measurements were performed using the images recorded by a fixed camera. A specific attention was paid to the hydraulic assumptions made for computing the river discharge from the LSPIV surface velocity measurements. Simple solutions for interpolating and extrapolating missing or poor-quality velocity measurements, especially in the image far-field, were applied. Theoretical considerations on the depth-average velocity to surface velocity ratio (or velocity coefficient) variability supported the analysis of velocity profiles established from available gauging datasets, from which a velocity coefficient value of 0.90 (standard deviation 0.05) was derived. For a discharge of 300m 3s -1, LSPIV velocities throughout the river cross-section were found to be in good agreement (±10%) with concurrent measurements by Doppler profiler (ADCP). For discharges ranging from 300 to 2500m 3s -1, LSPIV discharges usually were in acceptable agreement (<20%) with the rating curve. Detrimental image conditions or flow unsteadiness during the image sampling period led to larger deviations ranging 30-80%. The compared performances of the fixed and mobile LSPIV systems evidenced that for LSPIV stations, sampling images in isolated series (or bursts) is a better strategy than in pairs evenly distributed in time. © 2010 Elsevier B.V.
Pierrefeu G.,Compagnie Nationale du Rhone
Houille Blanche | Year: 2014
This paper summarizes the main techniques for measuring and controlling river flows. Most of technological advances have been made in the course of the last twenty years with the development of ultrasound, radar and video technical. The limits of use of these equipments and/or precautions that the user must implement will be highlighted. It will be reminded the context and challenges of river flow measurements that are very different in the laboratory. Indeed, in situ measurements are dependent on natural inputs or hydraulic structures operations as well as the morphological evolution of the river, including deepening of the bed or further aggradation following the floods. It's easier to plan laboratory tests in terms of repetition tests of measuring range or the shape of the flow sections to represent. Some of these measurement techniques will be illustrated by CNR experience for its concession or through experience shared with other agencies. The range of methods can be divided in the following areas: gauging method according to volume (weighing, dilution) or discretization the field velocity (exploration of the velocity field with current meter or profiler) and transfer law (rating curve for weir in river or hydraulic structure, index velocity with its ultrasound sensors immersed or non intrusive sensors like radar and LSPIV). All these methods have advantages and disadvantages. It is suitable for each of them, especially for innovative technologies to test and compare them with proven methods. Most of the time, validation will occur after a period of observation. After this adjustment phase, the equipment will provide data which reliability has been controlled. In fact, it often takes time to be able to scan the full range of use of equipment in situ and to detect its limitations of uses in order to validate them. In the field of hydrometry, improving the measurement process goes often, if not always, through the sharing of experience between different organizations. Indeed, the issues and the types of rivers are so different that it is desirable to gather the knowledge to move forward efficiently. © 2014 Société Hydrotechnique de France .
Compagnie Nationale Du Rhone | Date: 2010-08-24
Computer software designed to optimize the management of energy production in wind farms based on calculations made using automated and assessed weather forecasts for wind. telecommunications, namely, transmission of database information via telecommunications networks; communications by fibre optic networks; communications by computer terminals; satellite transmission; provision of access to a global computer network; providing and making available access to databases and to computer database server centers, namely, providing access to databases; electronic display services, namely, broadcasting communications services over the Internet or other communications network in the nature of electronic, electric and digital transmission of messages, data, sound and images; computer-assisted transmission of messages, data, sounds and images; providing telecommunications connections to a global computer network; e-mail services; electronic mail services and transmission and distribution of data or audio visual images via a global computer network or the Internet; all of the foregoing services being related to the optimisation of the management of energy production in wind farms. Software design in connection with the optimization of the management of energy production in wind farms; software installation, updating and maintenance in connection with the optimization of the management of energy production in wind farms; rental of computer software in connection with the optimization of the management of energy production in wind farms.
Compagnie Nationale Du Rhone | Date: 2011-12-13
Electronic apparatus comprising a user interface software and a geopositioning system comprising a GPS-based localization device for remote measuring, management, controlling and regulating of battery recharging in an electrically powered vehicle; battery chargers for electrically powered vehicles of battery chargers dedicated to electrically-powered or hybrid vehicles, within or outside of the vehicle; battery charging stations for electrically powered vehicles or hybrid vehicles. Electrically-powered or plug-in hybrid vehicles, namely, boats or terrestrial vehicles, namely, automobiles, trucks, buses, vans, motorcycles, motorscooters, mopeds and bikes. Transportation, distribution and supply distribution of electricity. Electrical engineering services; energy consulting, namely, technological consulting services in the field of alternative energy generation and production management; energy consulting services in the field of measurements to improve energy efficiency; scientific and industrial research in the field of energy; computer programming in the field of energy; analysis of technical data, namely, analysis of power consumption and generation to determine environmental impact; engineering services in the nature of technical analysis of power consumption and generation to determine energy efficiency; technical surveys for total energy optimization through management of the recharging of electric vehicles.
Compagnie Nationale Du Rhone | Date: 2015-08-13
Computer software for calculation of uncertainties regarding flow measurements carried out in rivers; apparatus and instruments for measuring speed of material in suspension contained in water flow; acoustic current doppler profiler (ACDP). Electricity generation, thermal energy production, climatic energy production, geothermal energy production, generation of electricity by solar energy, wind energy production, hydraulic energy production and renewable energy production services. Software development and design; installation, updating and maintenance of software; rental of computer software; engineering work, namely, surveying; computer programming, particularly in the energy and hydraulic field.
Compagnie Nationale Du Rhone | Date: 2012-10-23
Computer software for operating and controlling hydroelectric power stations. Telecommunication access services; communications by fiber optic networks; communications by computer terminals; satellite transmission; providing and making available access to databases and to computer database servers; rental of access time to database servers; electronic bulletin board services; computer-assisted transmission of messages, data, sounds and images; providing telecommunications connections to a global computer network; electronic mail; electronic mail services and transmission of information by electronic means via global communication networks, such as the Internet; all these services being in connection with operating and controlling hydroelectric power stations. Development (design) of computer software for operating and controlling hydroelectric power stations; installation, updating and maintenance of software for operating and controlling hydroelectric power stations; rental of computer software for operating and controlling hydroelectric power stations.