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Cet article présente un outil développé pour permettre l’aide à la décision spatialisée et la cartographie assistée par SIG. Baptisé RAIE (Répulsion, Attraction, Inclusion, Exclusion), cet outil permet à un interviewé ou à un groupe de personnes, lors d’entretiens semi-directifs, de produire des cartes dans un SIG à partir d’une ontologie déclarative. Révélant les enjeux et contraintes spatiales de différents acteurs pour la localisation d’un site, RAIE apporte également une base commune de données géographiques et de production de carte, contribuant à une décision multicritère spatialisée. This article presents a tool developed to enable spatialized decision support and GIS-assisted cartography. Called RAIE (Repulsion, Attraction, Inclusion, Exclusion), this tool allows an interviewee or a group, during interviews, to produce maps in a GIS from a declarative ontology. Showing the challenges and spatial constraints of different actors for the location of a strategic site, RAIE also provides a common database of geographic data and map production, contributing to a spatialized multicriteria decision. Este artículo presenta cartografías temáticas realizadas con Sistemas de Información Geográfica(SIG) que espacializan la toma de decisiones. Con la herramienta denominada RAIE (Repulsión, Atracción, Inclusión, Exclusión) se elaboran mapas temáticos con SIG de acuerdo con las ontologías explicativas utilizadas en las entrevistas semiestructuradas, tanto individuales o para grupos. El RAIE proporciona una base de información geográfica y de mapas temáticos que ayuda a la selección de una localización. Facilita la elección espacializada multicriterio evaluando los desafíos y las limitaciones espaciales de diferentes actores.

Marine dunes are sedimentary forms typically encountered on continental shelves. They migrate under the combined action of tidal currents and waves. Such an active environment poses a challenge to the design, safety, and maintenance of offshore and coastal works. Due to the continuous seabed evolution created by marine dune dynamics, offshore wind farm (OWF) elements, such as pile foundations and cables, are at risk of becoming exposed, weakening their integrity and stability, or on the contrary overburied, generating additional mechanical and thermal loads. Local scour at the toe of individual structures, and global scour resulting in the general lowering of the seabed around a group of structures, can also be elements of concern. Being able to predict the evolution and migration of marine dunes is, therefore, critical to limit damage to the infrastructures and to design effective protection works where needed.In this context, the present work will investigate marine dune dynamics at different spatial and temporal scales (from metres to kilometres, from days to years) using a complex process-based model: the suite of open-source numerical solvers TELEMAC-MASCARET. The objective is to gain a better understanding of the hydrodynamics, the sediment transport and morphological processes at play in a marine dune environment, as well as of the mutual interactions between the dune field and the OWF elements. The model capabilities to reproduce large-scale sediment transport processes in OWF environments and to obtain accurate diachronic predictions of the dunes’ evolution will be assessed in this work, and further developed if necessary.A large dataset (bathymetric surveys over several periods, metocean data, and sediment data) has been collected in the last few years for a proposed OWF project off Dunkirk, France. These data will prove invaluable to assess the model performance. They indicate dune migration rates of tens of metres per year in places. The site is subjected to relatively strong tidal flows, with a predominance of the flood towards the North-East. Waves are primarily from the South-West, travelling in the Channel, but some significant events from the North-North-East have been noted.This work is part of the 3-year MODULLES project: MOdelling of marine DUnes: Local and Large-scale EvolutionS in an OWF context, funded by France Energies Marines and the French government, under the “Investissements d’Avenir” programme managed by the French National Research Agency ANR. It is hosted by the Saint-Venant Hydraulics Laboratory (LHSV).

Cet article propose une reflexion sur les relations entre les observatoires, les infrastructures de donnees geographiques (IDG) et les besoins des utilisateurs pour le suivi spatiotemporel et environnemental des territoires. Apres un rappel de la nature et des objectifs des observatoires et des IDG, nous analysons, a partir d'etudes de cas, differents systemes d'observation, la mise a disposition des donnees geographiques collectees et l'adequation de ces infrastructures de donnees avec les besoins et moyens des usagers. Nous nous appuierons ainsi sur le cas de la collecte d'imagerie multispectrale (satellitaire et aerienne) et de la donnee hydrometrique (mesures de debits en riviere) pour illustrer quelques-uns des defis numeriques auxquels les observatoires doivent faire face pour atteindre leurs objectifs.

The exterior geometry of an urban project is defined at its early stages. The interior design and architectural details are not yet defined and indicators such as the “Daylight Autonomy” (DA) or the “Useful Daylight Indicator” (UDI) cannot be used. In this article, a link is established between both these indicators and the outside light sources luminances. The concepts of “sufficient, excessive and useful luminances” are introduced. In an unobstructed context, the DA and UDI inside a typical office room in Paris are estimated on the basis of the sufficient and useful luminances of the light sources visible from the window with differences inferior to 10% up to mid-depth. Considering an urban context, the differences reach 25% at mid-depth and the DA and UDI inside the room therefore cannot be estimated on the basis of these indicators. Meanwhile, they allow identifying the directions which are the most appropriate for daylighting, and therefore allow a better consideration of this aspect at early...

RESUMELes modeles pluie–debit sont fortement utilises dans la gestion des risques hydrologiques et la prevision des crues. Dans cette etude, nous presentons un modele pluie–debit pour la prevision des debits horaires base sur la technique des reseaux de neurones artificiels (RNA). Ce modele a ete developpe et applique sur le bassin versant de l’Eure au Nord-Ouest de la France afin de depasser les problemes dus a la non-linearite de la relation pluie–debit et a l’imprecision des donnees collectees. La creation de ce modele a necessite plusieurs etapes pendant lesquelles nous avons pu determiner les parametres du modele permettant la comprehension de la complexite hydrologique et la production des informations necessaires a la prevision. Elles ont abouti a un modele de reseau de neurones artificiels capable d’effectuer, en quelques secondes, des previsions des crues efficaces jusqu’a un horizon de prevision de 48 h. Ces resultats confirment que les modeles RNA peuvent jouer un role important dans le domaine...

International audience; Dans le cadre du projet ANR EMR_ITE PHYSIC (Processus Hydro-Sédimentaires enInteraction avec les Courants extrêmes), un modèle hydro-sédimentaire haute résolutiondu Raz Blanchard est développé à l’aide de TELEMAC. L’objectif de cettemodélisation est de prendre en compte à la fois les processus micro-échelles tels que lasaltation des galets et les conditions hydro-sédimentaires de la zone d’étude.Le modèle sera confronté aux observations collectées pendant les campagnes prévuespour le projet afin de le valider. Sachant que le Raz Blanchard est une zone à très fortscourants où l’instrumentation se fait difficilement, la validation et la paramétrisation dumodèle pour les courants s’appuiera également sur les données de la base de donnéescourant du Service Hydrographique et Océanographique de la Marine (SHOM)disponibles sur la zone

Resume : Les sediments marins sont le plus souvent consideres comme une composante environnementale dans les etudes preliminaires pour le developpement des Energies Marines Renouvelables (EMR). Ainsi pour la definition des zones de developpement des EMR, l’importance de la nature du fond marin et de sa dynamique est souvent sousestimee. Pourtant, la repartition, la nature et la dynamique des sediments pres du fond marin jouent un role crucial durant les phases d’installation, d’ancrage, de connexion ou de maintenance des infrastructures d’EMR. Des etudes sedimentologiques sur le plateau continental metropolitain menees au SHOM ont permis de mettre en evidence que les structures sedimentaires construites sous l’action des courants comme les dunes ou les bancs, constituaient de bons traceurs de la dynamique sedimentaire. Leur analyse morphologique detaillee et leur interaction avec des obstacles au fond comme les epaves permettent d’etudier l’impact potentiel des implantations d’EMR sur l’evolution des fonds marins et, inversement, l’impact de la dynamique sedimentaire sur les infrastructures en mer. Ainsi, l’influence du contexte sedimentaire sur le developpement d’infrastructures en mer agit a plusieurs niveaux : (1) influence de la nature des sediments et de leur repartition sur le choix des sites (possibilite d’ancrage, risques sur la mise en œuvre des infrastructures) ; (2) influence de la dynamique sedimentaire sur la mobilite des fonds et impacts sur l’installation des infrastructures (risques d’enfouissement, risques mines) ; (3) influence des changements hydrodynamiques induits par la presence d’obstacles sur le fond qui vont modifier la capacite d’erosion des sediments et engendrer des risques d’affouillement au niveau des ancrages et (4) influence du transport des particules sedimentaires dans la colonne d’eau qui peut exposer les systemes deployes a des risques d’abrasion (impacts sur l’usure et la perennite des installations). Une bonne connaissance des structures sedimentaires, de leur composition et de leur dynamique est donc fondamentale pour developper les EMR dans des conditions optimales de securite et de longevite. Mots-cles : Sediments, cartographie des sediments, dynamique sedimentaire, dunes, enfouissement, affouillement.

Sediment transport processes at the sediment-water interface are usually studied using flume tests. Due to technical limitations, extreme hydro-sedimentary conditions are then rarely considered. Sediment profile imaging (SPI) is a widely used technique for mapping benthic habitat quality in soft sediments but several limitations exist that make the system ineffective for coarse or indurate sediment investigations and for transport processes studies. To address this problem, a modified system was designed to investigate these processes in situ, on a grain-size scale, with high temporal resolution. A dynamic sediment profile imaging (DySPI) system was constructed with a new mode of penetration, an appropriate design and an imaging system based on high-definition video recording. The supporting frame was instrumented with autonomous sensors to monitor boundary layer characteristics along with video observations. This system was deployed during spring tide on sediment characterized by a mixture of particle sizes dominated by coarse grains. Appropriate image processing allowed determination of the area of sediment entrained, movement threshold, size of moving particles, instantaneous transport rate and interface profile changes, in addition to usual SPI parameters. However, DySPI is a prototype and further development of the instrument and the image processing are possible to enlarge the scope presented in this study.

In Paris (France), urban projects currently cover 10% of the territory. In the context of rising energy costs and the fight against climate change, reducing energy consumption in buildings and transportation is an unavoidable issue for these urban projects. While many studies analyse assessment tools and sustainability frameworks, only a few focus on developer practices. We describe how energy issues are integrated into urban development, focusing on three projects located in Paris. We compare environmental specifications made within these three projects to ensure high energy quality of the planned buildings. We observed that the way of prescribing energy performances varies from project to project. Differences in priorities from one engineering firm to another lead to a high variability of parameters identified to ensure high building energy performances.&

Flow over a side weir is one of the more complex flows to simulate in one-dimensional unsteady flow analysis. Various experiments have been applied, but no agreement is apparent in the literature about the best method. In this study, an Artificial Neural Network model has been used to extract a discharge equation for side weirs which accurately estimates overflow discharges. The proposed methodology gives the advantage of accounting for both the geometric and hydraulic characteristics of the overflow structure. The developed model is calibrated and validated using experimental data. Model calibration is achieved by using a Multi-Layer Perceptron (MLP), trained with the back-propagation algorithm. In order to highlight the advantage of the developed model over an existing model widely in use, the model's performance is evaluated according to three comparison criteria. The provided results clearly reflect the ability of the developed model to overcome the weakness of conventional models.

Urban development and the need for new facilities have led to an increase in the use of urban utilities. These various utilities are generally located under the public highway. Therefore, underground space is limited by the width of the public highway. Because of the increase in urban utilities, the need for maintenance of these utilities and the lack of space, the underground is now very often saturated. Sometimes, the situation is so inextricable and so anarchic that the implementation of a new urban network becomes hardly possible. In addition, trench digging due to work on existing networks or on the addition of a new network generates much traffic interruption. To solve this problem, an urban utilities tunnel can be used. In this case, all the urban utilities are located in a single tunnel. Thus, saturation of the underground space decreases, there are fewer errors in the zone plan used, maintenance is easier, there is no traffic interruption and it is possible to add a new urban network without disrupting the public highway. However, the urban utilities tunnel is expensive compared to classical solutions. Because decision-makers only work based on economic criteria, this solution is rarely chosen. Therefore, to promote the urban utilities tunnel in France, a national research project was created. One of its goals is to develop a multicriteria method integrating the following criteria: safety, sustainable development, economy, maintenance, risk analysis, development facilities… Moreover, the sewer network seems to induce most of the constraints. Thus, another goal is to study the influence of the drainage network location (inside or outside the tunnel) on the general cost of the urban utilities tunnel. This paper details both problems.

Today, more and more French communities have a critical point of view concerning the performance of their wastewater sewerage systems. The main reason is linked to the methodology of the studies in the design phase. The process is neither adapted to the complexity of the decision-making task, nor to a general management of the wastewater sewerage in a territory. In order to make these studies more coherent and the choices more rational, we propose a new formulation of the methodology as an alternative to the current one. Our approach relies on decision-making support which borrows concepts from expert systems and multicriteria analysis in order to structure the reasoning process and to take into account the very different criteria a real decision-making task often implies. We show that this support has to be interactive and iterative in order to ensure that coherent and relevant solutions are chosen.

The general obligation of a successful sewerage on any communal territory currently reaches its conclusion (December 31 2005). But in the case of waste water sewerage, previous programmes of modest size communities (less than 10 000 inhabitants) are still based on a methodology which takes into account neither the interactions between the different infrastructures, nor those with their environment. In order to make the decision process more rational and coherent, we propose in this article a methodological tool providing a decision-making aid support for choices of solutions. Its principle is based on an alternative reasoning with the current approach. This tool integrates concepts borrowed from the expert systems and from the multicriteria analysis.

Colloque avec actes et comité de lecture. internationale.; International audience; "Les outils actuels de gestion en temps réel des réseaux s’appuient sur deux outils logiciels : les logiciels de prévision météorologique et les logiciels de simulation hydraulique. L’usage des premiers est une cause importante d’imprécision et d’incertitude, l’usage des seconds oblige à des pas temporels de décision importants du fait de leur besoin en temps de calcul. Cette façon de procéder fait que les résultats obtenus sont généralement éloignés de ceux attendus.L’idée force du projet CARDIO est de changer de paradigme de base en abordant la problématique par la face « automatique » plutôt que par celle « hydrologie ». L’objectif est de rendre possible la réalisation d’un grand nombre de simulations en des temps très courts (quelques secondes) permettant de se passer des prévisions météorologiques en utilisant directement les données pluviométriques recueillies en temps réel. L’objectif est de parvenir à un système où la prise de décision est réalisée à partir de données fiables et où la correction de l’erreur est permanente.Les premiers résultats obtenus à partir d'une simulation d'un exemple test montrent l'efficacité de l’approche développée."

This paper presents a model for the hydraulic simulation of a drainage network using the storage concept. This model is easier to use than the complete Barre de Saint Venant equations and gives better results than the usual conceptual models, i.e. the Muskingum model, or than models obtained by the simplification of the Saint Venant equations (kinematic wave model and diffusion wave model).

Overflow structures built in combined sewer systems are often the source of hydraulic failure during wet weather conditions. Their modelling and particularly that of side weir overflows constitutes a very difficult task both regarding the quantitative and the qualitative aspects. In this paper, a new approach based on the video monitoring concept of these structures is proposed. This study aims at the adjustment of a measuring system able to take into account both spatial and temporal heterogeneity of discharges by digital cameras. In order to achieve this task, a full-scale experiment was carried out. Two lighting systems have been used. The acquired images from the experimental follow-up of the installation, over a period of about 15 months, are analysed. Image processing tools are used to determine the shape of the surface profile on the side weir and to transform image data into numerical data exploitable for modelling. The results were proved very satisfactory.

Très souvent, les services techniques ne disposent que du plan du réseau d'assainissement sans le profil en long. Or les cotes radiers sont nécessaires aux simulations hydrauliques effectuées, par exemple, lors des études diagnostic. Pour pallier ce manque, les bureaux d'étude effectuent généralement un relevé sommaire et interpolent linéairement les cotes radier manquantes. Cette interpolation linéaire peut être la source d'erreurs importantes. Nous proposons donc dans cet article une nouvelle méthode d'interpolation permettant de minimiser ces erreurs. Cette méthode utilise trois types d'informations : les données connues, les contraintes et les critères. Les données connues correspondent aux informations disponibles quant au réseau. Les contraintes sont les règles constructives auxquelles tout réseau d'assainissement doit se conformer. Les critères sont les règles d'optimisation construites à partir d'observations sur des réseaux réels. Pour résoudre ce problème d'optimisation sous contraintes, nous utilisons des algorithmes génétiques parce que ces derniers sont capables de travailler avec un grand nombre de variables, des nombres réels et des fonctions non-linéaires.Des tests ont été effectués sur les réseaux des villes d'Annequin, de Bapaume et de Lyon. Dans tous les cas (tronçons longs ou courts, pente forte ou faible), les résultats obtenus avec notre méthode sont meilleurs que ceux obtenus avec la classique interpolation linéaire. Il est même possible de déterminer la présence de contre-pente., In order to realise hydraulic simulations of urban drainage networks, data describing the networks are needed. Very often, some of the invert levels are missing. Usually, design departments carry out an incomplete survey of the network invert levels and then linearly interpolate the missing ones. Our objective is to propose a more precise method to interpolate unknown invert levels. The method we propose in this paper involves computing (interpolating) the missing invert levels by using three types of information: (network) known data, constraints and criteria. Known data correspond to the (assumed) available information. Constraints are construction rules that any urban drainage network must respect. Criteria are optimisation rules based on observations of real urban drainage networks. To solve this problem, we use genetic algorithms because these algorithms are able to work with many variables, real numbers and non-linear functions.Tests have been carried out on urban drainage networks in Annequin, Bapaume and Lyon. The results obtained are quite good for long or short reaches, and for steep or nearly flat slopes. It is even possible to identify the presence of negative slopes. In all cases, the proposed method of interpolation gives better results than the linear interpolation.

International audience; Acoustic scattering can be used to estimate Suspended Sediment Concentration (SSC) through acoustic inversion methods. Current SSC quantification methods are mostly unable to observe both spatial and temporal variations. Here, we assess the possibility to measure both using a Multibeam Echosounder (MBES). MBES combine a large spatial covering in the water column and the capability to measure ‘on route’, allowing a better representativity of the measurements. Time-series of raw EM3002-MBES data at 300 kHz were acquired during a 5-hours field experiment at a fixed location in the Aulne macrotidal estuary (France) during ebb, ensuring sufficient SSC variations. Concurrently, 4-frequencies Acoustic Backscattering System (ABS) profiles were acquired in the water column, as well as turbidity profiles, further converted into SSC using collected water samples. An original in-situ calibration was performed on the MBES, using a tungsten sphere of known properties, which allowed corrections to be made to the volume backscattered levels over the echosounder fan. Using ABS-derived equivalent radii, the MBES backscattered signal was inverted to retrieve an SSC estimate. Good consistency between MBES time-series observations and turbidity-derived SSC is observed. This experiment demonstrates the potential use of MBES for 3-dimensional turbidity observations in coastal areas, which is of great interest for sediment flux quantification.