Génie urbain urbanisme, assainissement et voiries, le cas de Tours

66 pages -La recherche portait sur les agglomérations de Tours et Brest. Ce texte ne rapporte que la recherche menée sur l'agglomération de ToursL'importance accrue des relations entre urbanisation et réseaux techniques (poids prépondérant des infrastructures de transports, problèmes posés par le cycle de l'eau, difficulté à cerner le rôle des réseaux informationnels, etc.) ont conduit l'Institut National du Génie Urbain de Lyon (INGUL) à initier une action de recherches sur le thème génie urbain et urbanisme. Un groupe de réflexion a exprimé les premiers éléments de cette action dans un rapport rédigé en 1993 . L'INGUL veut, dans ce cadre, développer une évaluation des rapports concrets entre génie urbain et urbanisme, évaluation qui doit conduire à l'élaboration d'un futur projet de recherche sur ce thème. Cette évaluation, l'Institut l'a voulue pilotée par des Agences d'Urbanisme, afin qu'elle s'accompagne d'une acquisition de connaissances destinée à déboucher sur une prise en compte plus opératoire du génie urbain dans le champ de l'urbanisme. Dans ce contexte, l'Atelier d'Urbanisme de l'Agglomération de Tours (AUAT) et l'Agence d'Urbanisme de la Communauté Urbaine de Brest et de son Environnement (AUCUBE) ont proposé à l'INGUL une étude sur les réseaux de voirie, les systèmes d'assainissement, et l'urbanisation, sur la période 1975-1995 dans les deux agglomérations de Tours et Brest. Cette étude se propose : - dans un premier temps, de décrire le système de relations tissées entre les grands choix en matière d'organisation de deux réseaux (la voirie et le drainage) et orientations majeures en matière d'urbanisation, sur les 20 dernières années; - puis, dans un deuxième temps, d'esquisser un certain nombre de questions et pistes de travail susceptibles d'approfondissement futu

Les versions dans les bases de données orientées objet : modélisation et manipulation

This thesis concerns object oriented databases; it proposes solutions to model and manage databases integrating versions. The concept of version is needed in various application fields such as technical documentation management, computer aided design and software engineering. Versions permit notably to keep and manage the evolution of the real world entities handled in such fields. There are different ways for versioning. Some works chose to describe the global evolution of a database; they manage versions of the whole database or versions of a database subpart. Our study focuses on representing independently the evolution of each entity described in the database. On the one hand, we propose a conceptual model extended to the versioning of objects and classes. Composition and relationship links, whose semantics are refined by cardinalities, integrate versioning for complex entities. Such links, including versions, induce complex contraints for structural integrity. On the other hand, we propose a language to manage this kind of databases. Particularly, this language provide a SelectFromWhere-type querying which take into account the specificities of versions; a query can take the most of the different abstraction levels related to versions that is to say derivation forests, trees and versions. The model and the language are realized within a prototype. This prototype is an end-user interface which provides a graphical management of databases integrating versions.Cette thèse s'inscrit dans le domaine des bases de données orientées objet ; elle propose des solutions pour décrire et manipuler des bases de données intégrant des versions. Le concept de version est nécessaire dans de nombreux domaines d'application comme la gestion de documentations techniques, la conception assistée par ordinateur et le génie logiciel. Les versions permettent notamment de conserver et manipuler l'évolution des entités du monde réel gérées dans de tels domaines. Différentes gestions de versions sont possibles. Certains travaux gèrent des versions de base ou d'une partie de base pour décrire l'évolution globale d'une base de données ; notre étude s'intéresse, quant à elle, à la représentation de l'évolution de chaque entité décrite dans la base, de manière indépendante. Nous proposons, d'une part, un modèle conceptuel intégrant la gestion de versions d'objets et de classes. Les relations de composition et d'association, dont la sémantique est affinée à l'aide de cardinalités, intègrent les versions pour des entités complexes. De telles relations, incluant les versions, induisent des contraintes d'intégrité structurelle complexes, dont nous faisons l'étude. D'autre part, nous proposons un langage pour manipuler ce type de bases de données. Ce langage permet notamment une interrogation de type Select From Where qui prend en compte les spécificités liées aux versions ; les différents niveaux d'abstraction liés aux versions c'est-à-dire les forêts de dérivation, les arbres et les versions, peuvent être exploités lors d'une interrogation. Une réalisation du modèle et du langage est effectuée au sein d'un prototype. Ce prototype est une interface destinée à des utilisateurs occasionnels, en permettant de manipuler graphiquement une base de données intégrant des versions

"Projet territorial et information géographique : les Conseils Généraux -v2", <br />in "Espaces habités, Espaces anticipés"

Rapport de recherche Agence Nationale de la Recherche"Espaces habités, Espaces anticipés ; qualification, appropriation, analyse"Module 7 : "Projet territorial et information géographique : Les Conseils Généraux"Coordonné par le Professeur Serge THIBAULTLe module "Projet territorial et information géographique" cherche à évaluer le rôle effectif de l'outil SIG dans l'appropriation par les Conseils Généraux de leurs nouvelles missions d'aménagement et de gestion de l'espace départemental, missions impactant aussi bien la vie quotidienne des habitants que la structuration future de leur espace. Dans un contexte de réorganisation profonde des services et des zonages d'action, au-delà des aspects techniques, le SIG participe aussi à une redéfinition des rôles en interne et à un nouveau mode de travail en réseaux et partenariats avec les acteurs des divers niveaux territoriaux. Le SIG – l'information géographique qu'il manipule- se révèle être à la fois un outil stratégique et un outil mal compris, dont la mise en œuvre repose plus sur la volonté des personnes que sur une organisation structuré

Contribution à la gestion de la retenue d'un barrage réservoir sur la rivièreSebou (Maroc) à l'aide d'un modèle hydraulique

Dans cette étude, on propose un modèle hydraulique capable de contribuer à la gestion des eaux de la rivière Sebou au niveau de la retenue d'un barrage de garde situé à l'intérieur de la plaine agricole du Gharb. Le modèle hydraulique élaboré (MHS.1) est du type filaire et utilise un schéma de différences finies. L'écoulement est influencé par la présence du barrage à l'aval et de nombreuses grandes stations de pompage utilisées pour l'irrigation le long du tronçon étudié. Cependant, les données relatives à la quantité d'eau pompée au niveau de ces stations ainsi que par les particuliers sont rarement disponibles. Ainsi, une attention particulière a été attribuée à l'estimation du pompage vue son importance quantitative. Les résultats du calibrage et de la validation du modèle pour des périodes de basses eaux de l'année 1997 sont très satisfaisants. Le modèle donne les valeurs du niveau d'eau aux stations de pompage et permet de suivre l'évolution de la réserve de la retenue du barrage. Ce code regroupe dans un seul outil des données provenant de différentes sources et utilisées pour la première fois dans un modèle hydraulique. Il représente un atout considérable pour les organismes publics gestionnaires des ressources hydriques.The studied reachThe Sebou River (600 km) is an important river in Morocco and its waters are solicited for several different uses. The Sebou has an average bottom slope of 10-4, variable geometry and many meanders. The flow is characterised by considerable annual and seasonal variations (Figure 2). The studied reach is situated between the town of Belksiri and the Lalla Aïcha dam. Flow is influenced by the presence of two dams, the Al Wahda upstream and the Lalla Aïcha in the downstream reach. The first dam was constructed on the Ouergha River, which has a torrential regime. The second dam comprises five principal and two secondary radial floodgates and these gates are opened from the bottom. This dam is completely opened during the period of high flows. The maximum flow during this season is 1800 m3/ s. The dam has a catchment area of 2700 km2. The maximum volume of the dam reservoir is 37 Mm3. Its length of influence is about 120 km.During the dry season, the floodgates are partially closed in order to increase the water level upstream. The maximum level upstream of the dam is 6.5 m NGM (the bottom is at -1 m). This situation facilitates the pumping of water for agriculture, allowing the irrigation of 15,600 hectares of rice. A volume of 200 Mm3 of water is mobilised annually, which, before the construction of the dam, was lost to the Atlantic Ocean.The hydraulic model MHS.1The hydraulic model MHS.1 is based on a modification (essentially the representation of the topography and the outputs) of the DYNHYD5 model. It solves the one dimensional Saint-Venant equations of continuity and momentum (equations 1 and 2). The Manning coefficient used in the momentum equation is evaluated initially by the empirical formula (Formula No. 3) proposed by Chow. The factor n0 is evaluated from granulometric measurements that were carried out from upstream to downstream in the studied reach. The others coefficients were evaluated from observations of the river in aerial photos, from the cross sectional areas and available photos, and from field visits. MHS.1 uses a network called ''Link-Node''. The equations of continuity and momentum, expressed in a finite difference manner, give respectively equations 4 and 5. These equations are solved using a Runge-Kutta procedure.Discretisation of the studied reachThe discretisation of the studied reach was performed using aerial photos achieved by the ORMVAG (L'Office Régionale de la Mise en Valeur Agricole du Gharb) in 1983. These photos were taking in a dry period where the river was nearly dry. This situation permitted a good stereoscopic visualisation of the river morphology. The river reach was divided into 529 grids with a length varying between 50 and 900 m. Data on cross sectional areas from the ORMVAG and other sources were used. Near the town of Souk Tlat (Figure 1), we exploited a new technique called ''Numeral photogrammetry'', which allowed us to reconstitute many cross sectional areas. This technique uses principally stereoscopic pairs of aerial photographs and photogrammetry software. The remaining cross sectional areas were evaluated from observations on aerial photos and from field visits.Evaluation of the pumped waterOne of the important factors that affect flow in the studied reach is the intensive pumping of waters along the river. The pumped water was divided into two types. The first type corresponded to the ten central stations managed by the ORMVAG (Fig. 1). The data of this first type were neither centralised nor easily available. Only the data at the important S2 station were readily available. The second type corresponded to water pumped by individuals and is less quantified than the first type.Two major hypotheses were adopted. First, the pumped flow at the S2 station was assumed to be equal to 25% of the total flow pumped by all the ORMVAG stations. The stations were classified into three classes according to their theoretical capacity (Table 1). This hypothesis allowed the estimation of the unknown pumped flow at the nine other stations. We further assumed that in the neighbourhood of each station, the flow pumped by individuals was equal to the flow pumped by the station. This latter hypothesis was adopted on the basis of a field investigation in a 7 km characteristic reach. Figure 3 shows the evolution of the overall pumped flow evaluated for the months of June and July 1997. These two months were used respectively for the validation and calibration of the model.Calibration and validation of MHS.1The Manning coefficient, estimated initially by the Chow formula (3), varied along the studied reach. It ranged from 0.02 to 0.04 s/m1 /3, with a mean value of 0.037 s/m1 /3. In the calibration procedure, the Manning coefficient was modified to the same degree along the studied reach because we assumed that the sources of errors involved in its evaluation are identical for all the grids.Along the studied reach, the only available measured data are the water levels at the S2 station and upstream of the dam. The period chosen for the calibration was from 07/01/1997 to 07/30/1997. The upstream boundary (at the Belksiri hydrological station) was given as values of the water level as a function of time (Figure 4). The downstream boundary was given as values of the discharge (flow through the dam gates) as a function of time (Figure 5). Figures 6 and 7 give the results of the calibration (month of July). The Manning coefficient decreased for all the reaches by 0.008 s/m1 /3. These figures show good agreement between the calculated and the observed water level at the S2 station and near the dam. In order to confirm the results of the calibration test, we proceeded with a validation test of the model for the period from 06/04/1997 to 06/30/1997. The results are also satisfactory (Figure 6 and 7, month of June).Figure 8 shows the evolution of the water level on 12/06/1997. The water level profile remains parallel to the bed profile for the zones situated very far from the dam (the downstream end). From the 45th kilometre (between stations S7 and S8, see Figure 1), we begin to detect the effect of the dam, characterised by an increase in the water level (and therefore an increase in depth). Figure 9 show the evolution of stream velocity from the upstream to downstream regions on 12/06/1977. Great variations in velocity can be seen due to the changes in river geometry. Also, these variations tend to decrease downstream, reflecting the effect of the dam.Figure 10 represents the evolution of the water reserve available for the whole reach during the months of June and July. It shows a series of decreases in this variable due to the pumping of water. The reserve reaches very low levels (15 Mm3) compared to its maximal capacity, which is 37 Mm3. Also, there is an interrelationship between the evolution of the reserve, and pumped water and the flow differences between upstream and downstream. The reserve increases when the upstream-downstream flow difference is greater than the pumped flow. Inversely, when the pumped water is greater, the water reserve decreases.Finally, in this study we proposed a mathematical model that can provide the stages at all locations of the studied reach, specifically at the pumping stations. Water reserve availability can also be provided at any moment, allowing rapid interventions when this variable begins to decrease dramatically. However, more measured water levels at different stations could improve the present results. Also, other considerations must be included such as hydroelectric energy production in dams upstream and river characteristics. Thus, a multipurpose model of the river must be used. More hydraulic data can improve the accuracy of the present model

La modélisation hydrologique et la gestion de l'eau

Cet article brosse un portrait de différents types de modélisation hydrologique développés à ce jour. Nous passerons donc en revue l'hydrologie, à l'érosion hydrique des sols, au transport et aux transformations des polluants et à la qualité de l'eau en rivière. Ce bref survol, nous amène à conclure que si le développement de la modélisation hydrologique s'est fait jusqu'ici essentiellement en affinant la description des processus et en considérant des échelles spatiales et temporelles plus fines, l'étape suivante passe par l'intégration de ces divers modèles. Cette intégration permettra dès lors de considérer un ensemble de problématiques directement liées aux aspects de gestion environnementale.This paper presents an overview of physically-based hydrological modeling approaches and a look at the future of hydrological modeling within the context of water management. It extends beyond classical hydrological modeling by surveying the modeling of water contaminants transport in porous media and surface waters, as well as soil erosion.Increasing concerns in predicting the impacts of land use management on the hydrological cycle have led researchers to construct two types of physically-based distributed models. The first type of model views the watershed as an ensemble of inter-connected reservoirs and mimics water routing with various types of discharge expressions and conceptual models (e.g., the infiltration models of Green and Ampt (1911), Holtan (1961) or Smith and Parlange (1978); the unit hydrographs of Sherman (1932) and Dooge (1973) and the geomorphological unit hydrograph of Rodriguez-Iturbe and Valdes (1979); the ground water discharge model of Beven and Kirby (1979); etc...). It is noteworthy that the pioneering Stanford Watershed Model of Crawford and Linsley (1966) led to the development of many currently used hydrological models including HBV (Bergstršm and Forsman, 1973), SLURP (Kite, 1978), TOPMODEL ( Beven and Kirby, 1979) and CEQUEAU (Morin et al., 1981), to name a few. The second type of model discretizes the watershed into an ensemble of control volumes and mimics water routing using combinations of partial differential equations for mass and momentum conservation and phenomenological models (e.g., Darcy's (1856), Dupuit's (1863), Boussinesq's (1904) and Richards (1931) equations for unsaturated and saturated flow in porous media; Saint-Venant's (1871) and Manning's (1891) equations for overland and open channel flows). Hydrological models such as SHE (Abbott et al.,1986a, b), IHDM (Calver, 1988), KINEROS (Woolhiser et al., 1990), THALES (Grayson et al.,1992) and HYDROTEL (Fortin et al., 1995), among others, represent classical examples of this type of modeling. It is noteworthy that recent advances in remote sensing and in digital elevation modeling have greatly facilitated and simplified the use of most of the hydrological models.On another front, the adverse effects of agricultural, industrial and urban runoff on surface and ground waters have motivated the development and application of different approaches to predict the fate and transport of various water contaminants in the environment (i.e., eroded soil particles, adsorbed and dissolved nutrients and pesticides as well organic matter).In soil erosion modeling, these concerns have led researchers to construct nonpoint source pollution models for evaluating the impacts of alternative land management practices on water quality. Based on the empirical Universal Soil Loss Equation (Wischmeier and Smith, 1978), the first nonpoint source models included CREAMS (Knisel et al., 1980), AGNPS (Young et al., 1987) and SWRRB (Williams et al., 1985). However, the lack of physical realism in these empirical formulations prompted the development of physically-based erosion models such as GUEST (Rose et al., 1983; Hairshine and Rose, 1992a, b), WEPP (Nearing et al., 1989), LISEM (De Roo et al., 1994) and EUROSEM (Morgan et al., 1992). The advantage of these models over the USLE resides in their ease of integration with physically-based hydrological models. Because of its close ties with the hydrological cycle and the soil erosion process (adsorbed and dissolved contaminants), the development of physically-based models for nutrient and pesticide transport benefited directly from advances in soil erosion modeling, soil chemistry and soil physics. The modeling of nitrogen transport is a representative example of this. Early modeling efforts involved the coupling of first-order kinetics models for the nitrogen cycle (Mehran and Tanji, 1974) with two types of mass conservation equation in porous media: the convection-dispersion equation and the capacity transport equation. Well known soil nitrogen dynamics models include NCSOIL (Molina et al., 1983), SOILN (Johnsson et al, 1987), EPIC (Sharpley and Williams, 1990), LEACHN and LEACHA (Hutson and Wagenet, 1991, 1992, 1993), DAISY (Hansen et al., 1991) and AgriFlux (Banton et al., 1993).The first attempt to model surface water quality goes back to the work of Streeter and Phelps (1925) who studied the impacts of a municipal waste water discharge on dissolved oxygen (DO) and biological oxygen demand (BOD) of an Ohio river. To predict DO and BOD dynamics, Streeter and Phelps assumed uniform and steady flow conditions and used first-order kinetics to model atmospheric supply of oxygen and oxygen consumption. The advances in computational power during the 70s and 80s allowed several researchers to substantially increase the complexity of the Streeter-Phelps approach. This was achieved by accounting for advection-dispersion phenomena, unsteady two and three dimensional flow conditions, as well as the effect of temperature on various chemical reactions. The QUAL2E model of Brown and Barnwell (1987) is a good example of a moderately complex water quality model where advection-dispersion and temperature effects on several water characteristics and contaminants are considered under one-dimensional steady flow conditions.At present, the state of hydrological modeling and software engineering has reached a point where it is now possible to construct spatial decision support systems (SDDS) capable of simulating the impacts of various management practices (i.e., industrial, municipal and agricultural) on the water quantity and the quality of a watershed's river network. These systems, which idealy should be user-friendly for decision makers, will be both integrated modeling systems (including a database system, hydrologic, soil erosion, agricultural-chemical transport and water quality models) and spatial data analysis systems (including a geographical information system). Currently developed SDDS include PÉGASE (Smitz et al., 1997) and GIBSI (Villeneuve et al., 1996, 1997a,b). In a sustainable water management context, the use of such systems will provide decision makers with a complete tool for exploring a variety of integrated watershed management programs

Schéma d\u27orientation stratégique de l\u27information scientifique et technique (IST), "Mieux partager les connaissances"

Mettre les données de la recherche à la portée de tous : éternelle promesse ou révolution ? Le CNRS prend le sujet à bras le corps avec une nouvelle stratégie en matière d\u27information scientifique et technique (IST). Adoptée par le collège de direction du CNRS le 13 novembre 2013, elle résulte d\u27un travail approfondi entre la direction de l\u27information scientifique et technique (DIST), les universités et les organismes de recherche