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Current paper contributes towards a hydrodynamic modeling of the main drinking water source of Belem, the capital of the state of Para, Brazil. Belem is one of the largest cities in the Brazilian Amazon region, with a population of approximately 1,500,000 inhabitants. The Utinga water source is formed by lakes Agua Preta and Bologna connected by a canal. The literature presents the separate modeling of the lakes, without considering the canal, highlighting the motive of current research. Topography data were collected in the field to supplement data on the lakes and the canal data, provided by the local Sanitation and Water Supply Company (COSANPA) and by the Development and Administration Company of the Metropolitan Area of Belem (CODEM). The Saint–Venant 2D model vertically integrated had its equations discretized by the finite element method and applied to simulate velocities and depths of the lakes and the canal. The mesh generated is formed by six-node triangles (T6L). Mesh stores data on topography, substrate and boundary conditions. Resulting model revealed that the simulated depths and velocities corroborate those available in the literature, except in some cases when simulated velocities were slightly higher. In the case of the interconnecting canal, it is the first time that velocities and depths are simulated and analyzed. Simulated velocities and depths are input data for dispersion models of pollutants and sediment transport. Models must be developed to provide support for the management of water resources that supply most of the city. The above is important since irregular residences discharge untreated sewage into the Utinga source, favoring the proliferation of macrophytes in the lakes Bolonha and Agua Preta. Untreated sewage discharge also increases water treatment costs.

Extreme climatic conditions likely caused a massive fish mortality during the summer of 2001 in the St. Lawrence River. To corroborate this hypothesis, we used a physical habitat simulation approach incorporating hydraulic and water temperature models. Spawning Habitat Suitability Indices (HSI) for common carp (Cyprinus carpio) were developed using fuzzy logic and applied to the model outputs to estimate habitat weighted usable area during the event. The results revealed that areas suitable for common carp spawning (HSI &gt, 0.3) were severely reduced by high water temperatures, which exceeded 28 °C during the mortality event. During the mortality event, the amount of suitable habitat was reduced to &lt, 200 ha/day, representing less than 15% of the maximum potential suitable habitat in the study reach. In addition, the availability of cooler habitats that could have been used as thermal refuges was also reduced. These results indicate that the high water temperature in spawning areas and reduced accessibility to thermal refuge habitats exposed the carp to substantial physiological and environmental stress. The high water temperatures were highly detrimental to the fish and eventually led to the observed mortalities. This study demonstrates the importance of including water temperature in habitat suitability models.

Accurately characterizing the spatiotemporal dynamics of residual and tidal flows is essential for understanding transport processes in tidal rivers and estuaries, as they directly affect salinity intrusion, water renewal capacity, sediment transport, and morphological evolution. This paper aims at characterizing the longitudinal and temporal variability of tidal discharges and currents in the St. Lawrence fluvial estuary (SLFE), under a wide range of river flow and tidal conditions. Tidal discharges and currents are reconstructed by cubature from nonstationary tidal analyses of water levels for a highly variable year, in terms of observed river flows, at 10 river cross-sections of the SLFE, distributed from the fluvial estuary entrance to the head of the tide. An analysis of the spatiotemporal variability in residual and tidal flows is hereby provided, with an emphasis on ebb-flood characteristics, residual currents, tidal constituent properties and tidal wave propagation characteristics at the intratidal, neap-spring and seasonal scales along the system. The main drivers and mechanisms responsible for this variability include (1) the system's hydrology and its associated watershed and meteorological characteristics, which dictate river flow intensity and seasonality, (2) the landward-travelling tides originating from the ocean, responsible for intratidal and tidal monthly variability in tides and currents, (3) nonlinear river-tide interactions, dissipating tidal energy, modulating tidal properties and inducing a surface level gradient, and (4) channel convergence and floodplain morphology, contributing to tidal asymmetry in horizontal and vertical tides. These factors ultimately influence tidal wave propagation and damping properties within estuaries, both longitudinally and at the neap-spring and seasonal scales.

Knowledge of tidal flows in rivers and estuaries is often scarce yet vital in determining flushing properties and sediment transport rates. While many rivers still remain ungauged, methodological difficulties often arise in gauged systems, resulting in short flow records compared to historical water level data. Notwithstanding, discharge reconstructions in estuaries are possible using indirect methods based on long‐term tidal data. In this paper, we revisit the method of cubature, integrating the continuity equation for discharges at different sections. The method consists in computing temporal changes in water volume from simultaneous tidal heights readings along the river and storage width estimations. These water balance estimates remain challenging to produce, because they require spatial interpolation of gappy tidal records and an accurate representation of inundated areas over time. Improvements on the method are made by using a 1D nonstationary tidal harmonic model that provides continuous tidal data along the estuary, with no temporal or spatial gaps. Secondly, a 2D finite element discretization is used to compute the time‐varying wetted surface area, relying on detailed topographic data over intertidal flats. The method is applied to the St. Lawrence fluvial estuary (SLFE) and validated against discharge data collected along 9 cross‐sections of the river, reaching relative RMSE below 4% of the diurnal tidal discharge range at downstream locations and below 9% upstream. One‐year reconstructions conducted in the SLFE also show the potential of the method to reproduce the tidal discharge variability along the tidal‐river continuum, for a wide range of temporal scales.

Maximizing the performance of hydropower plants by taking advantage of the remaining energy downstream of dams via the installation of hydrokinetic turbines is feasible. In these cases, the design of the rotor diameter and velocity are fundamental and depend on the depth and velocity of the river, respectively. In this study, the Saint-Venant model was applied and calibrated by linear regression of measured and simulated flow rates, which resulted in a correlation of 0.99. The validation was performed using measured velocities that are comparable to the simulated velocities. A power curve was generated for the measured flow rates and simulated velocities and obtained a correlation of 0.96. The curve was used to estimate the velocity, calculate the energy density, and define a design velocity of 2.35 m/s. Ten points in the study area were selected for the turbine locations, and the velocities were determined using the power curve for the measured flow rates and simulated velocities. The rotor design was performed using the blade element method (BEM), and a rotor diameter of 10 m was defined. The 10 turbines can generate 2.04 GWh/year of electricity. The results demonstrate the potential for utilising the remaining energy of hydroelectric plants.

Modeling the spatial distribution of mobile organisms under rapidly changing environmental conditions is a challenging endeavor that has to be undertaken whenever the impacts of alterations have to be assessed in dynamic scenarios. We modeled habitat suitability for Lake sturgeon (Acipenser fulvescens) and White perch (Morone americana, both had have been followed by hydro-acoustic telemetry) in an estuarine river section with rapidly changing tidal and hydrodynamic conditions using deep feed-forward Artificial Neural Networks (ANN). Descriptors used were of many types: intrinsic features (species, sexual maturity and gender, and individual character), terrain features, hydraulic and tidal conditions, and time. A set of ANN models with varying degree of complexity, in terms of their number of hidden layers, number of nodes per layers, and regularization parameters, were tried and evaluated using cross-validation. The best model has three layers with 100, 50, and 20 nodes and classified 94.0 % of observations as presence (and 60.6 % of pseudo absences as absences, overall correct classification: 77.3 % ) during the trials. The study highlights that tidal and hydraulic models, coupled with acoustic telemetry and machine learning, can be used to predict the spatial distribution of mobile organisms even in extremely variable ecosystems such as estuaries.

FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas Na cidade de Belém está localizado o sistema de abastecimento de água potável de sua região metropolitana, que inclui, além desta cidade, mais quatro municípios. Neste complexo de fornecimento hídrico encontra-se o lago Água Preta, que serve como um reservatório para as águas bombeadas do rio Guamá. Devido à grande importância deste lago para este sistema, vários trabalhos foram dedicados ao seu estudo, desde o monitoramento da qualidade de suas águas até a sua modelagem hidrodinâmica. Este artigo apresenta os resultados obtidos pela simulação computacional da dispersão de fósforo dentro deste reservatório a partir da solução numérica da equação bidimensional de advecção-difusão-reação pelo método θ/SUPG. A comparação destes resultados com os dados de concentração do fósforo total coletados no período de novembro de 2008 a outubro de 2009 e fotos de satélite apontam que os maiores poluidores das águas deste lago são os despejos de esgotos domésticos pela população que habita em suas proximidades. Os resultados obtidos indicam a necessidade de mais informações para analises quantitativas mais precisas. Entretanto, eles mostram que o fósforo trazido pelas águas do rio Guamá é consumido em uma área próxima do canal que transporta esta água para dentro do lago. Os depósitos de fósforo no fundo do lago devem ser monitorados para se verificar os seus comportamentos, prevenindo assim a qualidade da água mantida nele. In Belém city is located the potable water supply system of its metropolitan area, which includes, in addition to this city, four more municipalities. In this water supply complex is the Água Preta lake, which serves as a reservoir for the water pumped from the Guamá river. Due to the great importance of this lake for this system, several works have been devoted to its study, from the monitoring of the quality of its waters to its hydrodynamic modeling. This paper presents the results obtained by computer simulation of the phosphorus dispersion within this reservoir by the numerical solution of two-dimensional equation of advection-diffusion-reaction by the method θ/SUPG. Comparing these results with data concentration of total phosphorus collected from November 2008 to October 2009 and from satellite photos show that the biggest polluters of the water of this lake are the domestic sewage dumps from the population living in its vicinity. The results obtained indicate the need for more information for more precise quantitative analysis. However, they show that the phosphorus brought by the Guamá river water is consumed in an area adjacent to the canal that carries this water into the lake. Phosphorus deposits in the lake bottom should be monitored to verify their behavior, thus preventing the quality of water maintained therein. LIMA, R. C.; MESQUITA, A. L. A.; BLANCO, C. J. C. Universidade Federal do Pará

This is the second part of an investigation aimed at documenting the tidal hydrodynamics of the St. Lawrence fluvial estuary (SLFE). In Part I, the calibration and validation of a high-resolution, two-dimensional (2D), time-dependent hydrodynamic model of the SLFE was presented. Herein, the process-based (structural) validation procedure used to quantitatively assess the ability of the model to reproduce spatial and temporal patterns observed in the field data is presented. Tidal and flow features were found to be reproduced satisfactorily in terms of their lateral and longitudinal variability at both the intratidal and fortnightly scales. These properties can be used to describe the real system dynamics, including flooding–drying processes, tidal propagation and modulation, and transient momentum balance, providing insights into the general physical processes of the SLFE and of large tidal rivers globally.

In this study, a high-resolution, two-dimensional (2D), time-dependent hydrodynamic model of the St. Lawrence fluvial estuary was developed with the objective of documenting the tidal hydrodynamics of this complex yet poorly understood region. The hydrodynamic model solves the shallow-water equations over a finite-element–discretized domain, with an average spatial resolution of 50 m, and includes a drying–wetting component for the treatment of shallow intertidal areas. The numerical terrain model is composed of high-density topographic data and detailed friction fields associated with bottom substrate and macrophytes. Calibration and validation were carried out using recently acquired data for water level and velocity. Results show very good accuracy in water levels, with prediction skills higher than 0.99 at all stations (where a skill of 1 means perfect agreement between model and observations in terms of their relative average error) and root-mean-square errors (RMSEs) less than 5% of local tidal ranges downstream; at upstream stations where tidal ranges are significantly reduced, RMSEs were lower than 6 cm. Discharges were reproduced with similarly good accuracy, with errors lower than 6% of the maximum observed discharges at 11 of the 13 surveyed transects; the two remaining sections are subject to larger interpolation and bathymetric uncertainties. In this paper, critical aspects of model development are discussed, including the 2D approximation, temporal and spatial resolution, bathymetric uncertainty, error in the boundary conditions, and calibration under nonstationary conditions. This work is the first part of a two-part investigation serving as a methodological framework for model setup, calibration, and validation in large tidal rivers.

Predicting tides in upstream reaches of rivers is a challenge, because tides are highly nonlinear and nonstationary, and accurate short-time predictions of river flow are hard to obtain. In the St. Lawrence fluvial estuary, tide forecasts are produced using a one-dimensional model (ONE-D), forced downstream with harmonic constituents, and upstream with daily discharges using 30 day flow forecasts from Lake Ontario and the Ottawa River. Although this operational forecast system serves its purpose of predicting water levels, information about nonstationary tidal-fluvial processes that can be gained from it is limited, particularly the temporal changes in mean water level and tidal properties (i.e., constituent amplitudes and phases), which are function of river flow and ocean tidal range. In this paper, a harmonic model adapted to nonstationary tides, NS_TIDE, was applied to the St. Lawrence fluvial estuary, where the time-varying external forcing is directly built into the tidal basis functions. Model coefficients from 13 analysis stations were spatially interpolated to allow tide predictions at arbitrary locations as well as to provide insights into the spatiotemporal evolution of tides. Model hindcasts showed substantial improvements compared to classical harmonic analyses at upstream stations. The model was further validated by comparison with ONE-D predictions at a total of 32 stations. The slightly lower accuracy obtained with NS_TIDE is compensated by model simplicity, efficiency, and capacity to represent stage and tidal variations in a very compact way and thus represents a new means for understanding tidal rivers.

Cross-sectional gradients in water levels and velocities play a determining role in the circulation dynamics of tidal rivers and estuaries. Documenting and analyzing their variability throughout a tidal cycle require observations with high spatial and temporal resolution. A survey strategy and a data analysis procedure have been designed to obtain continuous and synoptic water level and velocity fields over a tidal cycle, along 13 cross-sections of the St. Lawrence fluvial estuary dominated by large tidal ranges. The method combines both RTK GPS and ADCP technologies for the simultaneous measurement of water levels and velocities along repeated boat transects, allowing fast data acquisition over wide river sections and under rapidly changing conditions. The reconstruction of continuous and synoptic fields is made by interpolation. Simplifying assumptions about data stationarity and/or homogeneity are avoided by adapting the interpolation procedures to the shape and distribution of the underlying data in a space-time reference frame, thus minimizing distortion in the reconstructed quantities. The capabilities and limitations of the method are assessed through error computations and comparisons with alternate data analysis methods and complementary data sets from tide gauges. With these latest observations, new insights into the tidal hydrodynamics of the St. Lawrence fluvial estuary are gained in regions of contrasting tidal and fluvial properties, specifically related to the effects of channel curvature and bathymetry on tidal propagation and cross-channel flow properties at the intratidal scale.

Measuring temporal and spatial variations in water level with high resolution and accuracy can provide fundamental insights into the hydrodynamics of marine and riverine systems. Real-time kinematic global positioning systems (RTK GPS), and by extension postprocessed kinematic (PPK) positioning, have provided the opportunity to achieve this goal, by allowing fast and straightforward measurements with subdecimeter accuracy. However, boat-mounted GPS are subject to movements of the water surface (e.g., waves, long-period heaves) as well as to the effects of dynamic draft. The latter contaminate the records and need to be separated and removed from the data. A method is proposed to postcorrect the elevation data using tilt information measured by an attitude sensor—in this case, an acoustic Doppler current profiler (ADCP) equipped with internal pitch and roll sensors. The technique uses iteratively reweighted least squares (IRLS) regressions to determine the position of the center of rotation (COR) of the boat that leads to optimal corrections. The COR is also allowed to change in time by performing the IRLS analyses on data subsamples, thus accounting for changes in weight distribution, for example, due to personnel movements. An example of application is presented using data collected in the Saint Lawrence fluvial estuary. The corrections exhibit significant reductions associated with the boat motion while keeping subtle variations in water levels likely related to local hydrodynamics.

Climate change and sea-level rise are likely to have a significant impact on the low-lying coastal areas of Brazil around the Amazon estuary. However, the huge river flows – equivalent to a fifth of the world's total – combined with strong tidal effects and complex coastal morphology make the design and analysis of future flood protection works particularly challenging. This paper reports on the development, calibration and application of a successful hydrodynamic model for a new flood embankment in the coastal city of Belém. The model uses a geographic information system and finite-element method to solve shallow water equations, and appears suitable for wider application in the Amazon estuary.

A daily averaged two-dimensional water temperature model has been developed for the freshwater part of the St. Lawrence River, between Lake St. Louis and Trois-Rivieres (Quebec, Canada). The model was first calibrated and validated for the area of Lake St. Pierre, a natural enlargement of the river subject to strong lateral and longitudinal thermal variations. Forecasts from the Global Environmental Multiscale model were used in preference to observations from meteorological stations for model inputs, both to increase the spatial resolution and ultimately to allow the water temperature model to be used in predictive mode. The resulting model provided daily water temperature estimates with an overall root mean square error (RMSE) of 1.18 � C and a Nash–Sutcliffe coefficient of 0.44. Comparisons between Landsat images and simulations demonstrated that the model not only simulated accurate water temperature values but also showed the adequacy of the model in general. It not only simulated local water temperature relatively accurately but also provided a good representation of the spatial water temperature patterns within the study area. The error varied between deep and shallow water areas. In deeper water, the overall RMSE is 0.41 � C, and the modified Nash coefficient rises up to 0.92. Because shallow water areas are subject to greater variations, longer, more spatially dense data sets will be needed to refine the hydrodynamic and thermal budget models for those specific areas. Copyright © 2013 John Wiley & Sons, Ltd.

One of the challenges when modelling a complex variable such as water temperature in rivers is that it can be difficult to determine the sources of error and to ensure that the simulations are truly representative of the reality. Therefore, a heat budget study was completed in a controlled environment, which excluded advection and bottom fluxes but enabled observation of all the other fluxes. A 21.42 m3 pool was installed and insulated to limit heat exchange through the sides and bottom. All the major energy fluxes were monitored for a 50-day period. Different equations for individual heat budget terms were tested to determine their ability to reproduce the observations. This experiment also permitted to assess the relative importance of each component of the heat budget. Performance of each semi-empirical equation was determined by comparing predictions and measured values. It was thus possible to choose the formulae that best represented the measured heat exchange processes, while understanding the limits of some of the semi-empirical representations of heat exchange processes. The results highlight the importance of radiative terms into the heat budget because they controlled the major sources and sinks. The study also showed the importance of the wind function determination into the calculation of latent heat flux. The resulting water temperature model returned simulated hourly water temperature with an overall root mean square error of 0.71 °C/h and a modified Nash–Sutcliffe coefficient of 0.97. Copyright © 2012 John Wiley & Sons, Ltd.

This work describes the steps required to construct a hydrodynamic model of the Guajará Bay, using Geographic Information Systems and the Finite Element Method. An overview of the problem that motivates this modelling procedure, i.e., the pollutant dispersion, is presented. The computer software used is then discussed, stressing the links between the data model entities. The calibration procedure is described. The methods used to obtain field data and the results obtained are presented, alongside the main flow patterns of the water. The simulations and applications of the model are discussed at the end of the paper.

This paper introduces an algorithm to calculate outflow in lakes and reservoirs that have multiple outlets. If the inflow into the lake, the surface area, and the morphological characteristics of the outlets are known, this algorithm enables to calculate the outflow at each outlet of the lake at any moment in time. Lake outflow is governed by a mass balance equation and a relationship that relates water level to outflow at each outlet. This algorithm was first validated using a theoretical example and once the method was integrated into the distributed hydrological model HYDROTEL, it was also validated using simulation of Lake Ludger, Quebec, Canada.

One of the main obstacles to the socio-economic development of the Brazilian Amazon is the lack of electric energy in the numerous small isolated communities of the region that hampers value-added agricultural production, revenue growth and creation of jobs. One way to solve this problem is by setting up micro-hydro power (MHP) plants under a sustainable development perspective. This paper presents a decision support system (DSS) that analyzes this solution. The system considers the hydrological, topographical, geotechnical, environmental, energy, economic and social aspects of the target site. A detailed analysis is made of the hydrological model that employs a rainfall run-off model for small catchment analysis; the energy planning favors a two-turbine method to determine the maximum energy production during demand peaks, and the economic aspects show that the costs of energy generated by MHP plants are comparable to those from rural grid systems and lower than those from from diesel generators. Thus, the use of the hydro-power resources of the small catchments of Amazonia combined with the minimization of the environmental impacts caused by MHP not only fulfills the energy demand of the small communities of region, but is also viable economically along with job creation and revenue generation, and it supports the perspective of sustainable development.

In Amazonia, because the small catchments are ungauged, it is not possible to analyse them, for example, for hydroelectric power production. Thus, the objective of this paper is to study the transferability of a rainfall–runoff model to simulate flow duration curves for the production of hydroelectric power. The approach is based on the transfer of the impulse response of a model calibrated on two gauged catchments, allowing the evaluation approach permutation between these two catchments. We have, respectively, 7 years and 2 years and 2 months of rainfall and runoff data for these catchments. A sensitivity analysis of the transferability calibration to the sample size is carried out to determine the shortest flow period gauged on the receptor catchment, which produces results comparable to those calibrated with the maximum samples size. This analysis evaluates fieldwork on the ungauged sites of the region.

In Amazonia, hydroelectric power production has only been developed on large basins, which are the only ones that have been gauged. This excludes innumerable small catchments, for which only rainfall data are available. Therefore, the objective of the work presented in this paper is to develop a hydrological rainfall–runoff model to simulate flow duration curves for hydro power production planning. The model is based on a linear and time-invariant system (input–output). The impulse response of the system is calculated from the cross-spectral analysis between the rainfall and runoff series. This response is optimized successive approximations to minimize the root mean square of the error. The test catchment area has 7 years of rainfall and runoff data; 4 years are considered for the calibration and 3 years for the validation of the model. A sensitivity analysis of the model to the sample size is carried out to determine the shortest possible data period that produces results comparable to those of the model validation. Key words: model rainfall–runoff, small catchments, Amazonia, impulse response, sensitivity analysis.

La validation par les vitesses d’un modele hydrodynamique montre que la variabilite du profil vertical des vitesses a une influence importante sur le resultat. Ici, cette variabilite a ete introduite sous la forme d’un terme de dispersion dans un modele hydrodynamique qui resout les equations de Saint-Venant 2D par la methode des elements finis. Nous tentons ensuite de la representer a l’aide des variables du modele (u, v, h). Le modele applique a un canal courbe de 270° montre que la variabilite spatiale de la distribution des vitesses est amelioree, que ce soit par la prise en compte de la variabilite mesuree ou par le parametrage de celle-ci. Une application est effectuee sur la riviere des Escoumins, petit cours d’eau alluvionnaire a la topographie complexe. Les resultats montrent que la modification du modele de Saint-Venant ameliore la description de l’ecoulement mais ne suffit pas a representer correctement celui-ci.

Flood risk management for residences requires an economical analysis involving the mean annual damage by floods, taking into account the whole range of probability of floods and the cost of projected fluvial enhancements and measures, taking also into account the residual level of risk. Efficient methods are therefore necessary to estimate these risk values. The proposed approach is of a "distributed" type; it involves numerical modeling for estimating "residential submersion depth", a variable, which explains most of the direct damages to residences. The method relies on an individualized georeferenced definition of each residence. Measured submersion data and the compensations obtained from the huge Saguenay flood in 1996 (Ville de Laterrière) were used to build empirical laws based on submersion. Four distinct relationships were established: residences with or without a basement and valued below or above $50,000 each were assigned a specific relationship. With these relationships, direct residential damages in Laterrière were assessed by using only simulation results at the georeferenced position of sector residences as input. It was then possible to evaluate the total amount of direct home damages in Laterrière.Key words: flood, risk, damage rating curves, Saguenay floods, numerical modeling, predictive model, georeference, geographic information system.

The St. Lawrence River is one of the most important large rivers in North America. This 600–km long watercourse is characterized by a high degree of physical heterogeneity, including fast moving narrow reaches separated by fluvial lakes reaching 10 km in width. The mean annual discharge from the outflow of Lake Ontario is 7500 m3/s and has been managed for hydropower and transportation since the 1960s. With the management plan currently under review an effort is being made to include criteria that take into account the impacts of regulation on the biotic components of the river ecosystem. High resolution 2D spatial modelling of river habitats and floodplains is a powerful tool to make quantitative impact assessments of the biota. Physical variables commonly used in habitat models include depth, velocity and substrate size. In addition, other abiotic variables such as wind– generated wave stress, light penetration, water temperature, sedimentation of fine particles, specific discharge and bottom slope, that define the local ‘hydroperiod’ have been suggested. Our proposed approach integrates abiotic data obtained from numerical models, field measurements and biological information to overcome problems inherent in temporally and spatially heterogeneous river systems. This approach was tested with a habitat model applied to submerged aquatic vegetation, various categories of wetlands, benthic organisms and various life stages of a number of fish species. Logistic regression is the statistical model currently used to synthesize the relationships between abiotic and biotic factors. The short–term objective of this modelling exercise in the St. Lawrence River is to understand the underlying links between fluvial physics and biota. A longer–term objective is to provide a real–time analysis of key variables and to quantify the links between trophic levels. Le fleuve Saint–Laurent est une des plus importantes rivieres d’Amerique du nord. Son parcours de plus 600 km est caracterise par une forte heterogeneite spatiale, puisque compose d’une succession de troncons relativement etroits et de lacs fluviaux de plus de 10 km de largeur. Le debit moyen annuel sortant des Grands Lacs est de 7500 m³/s. Celui–ci est regularise depuis les annees 1960 et le plan de gestion fait actuellement l’objet d’une revision pour ajouter des criteres tenant compte des impacts sur le milieu aquatique. La modelisation 2D a haute resolution spatiale des habitats du fleuve et de sa plaine inondable est un outil privilegie pour apporter des reponses quantitatives aux impacts du milieu physique sur les ressources fauniques et floristiques. Les variables traditionnelles de la modelisation des habitats que sont les courants, la profondeur et le type de substrat sont utilisees. Afin d’adapter la modelisation des habitats a des contextes varies, de nouvelles variables abiotique sont ete developpees parmi lesquelles on retrouve les contraintes des vagues generees par les vents, la penetration de la lumiere, la temperature de l’eau, la sedimentation des particules fines, le debit specifique, la pente du fond ainsi que des variables reliees a l’« hydroperiode » locale. Les relations entre habitats et facteurs abiotiques ont ete evaluees statistiquement a l’aide de regressions logistiques. La modelisation des habitats a ete appliquee a plusieurs compartiments du vivant, tels que les macrophytes submerges, plusieurs classes de milieux humides et diverses especes de poissons a certains stades de vie critiques. L’approche actuelle integre les donnees provenant de la modelisation numerique des facteurs physiques, de la caracterisation du terrain et d’echantillonnages d’organismes vivants, elle permet de simplifier des problemes complexes relies a l’heterogeneite spatiale et aux echelles temporelles inherentes aux milieux naturels. L’objectif de la modelisation du fleuve est de comprendre les liens entre la physique et les habitats de la faune et la flore et afin de soutenir un suivi fiable de l’ecosysteme.

A new Eulerian approach is proposed to track the dynamic position of flow boundaries in rivers with respect to flow discharge or tides. Associated to a two dimensional (2D) transient horizontal hydrodynamic model, it allows to define the configuration of watercourses in a broad hydrological register varying from dry conditions to severe flooding. The finite element method is used to develop the numerical prediction tool. It is employed to estimate not only the classical flow variables such as water surface level and velocity field, but also the position of the shorelines. In this paper, the strategy followed for building this «drying-wetting» model consists in letting the water surface move freely, everywhere in the domain including the dry zones, allowing it to plunge under the ground. Two practical applications on rivers of Quebec (Canada) are presented. The first one deals with steady state situations on St. Marguerite River. The second one deals with the reconstitution of flood propagation on Chicouti...

Lake Saint-Francois is the first fluvial lake downstream of the Great Lakes. Aquatic macrophytes are abundant because of water level stabilization and increased nutrient loads. The influence of plants on flow modification is very important and must be considered in order to simulate hydrodynamic conditions. The spatial distribution of plant species is linked to their instream flow preferences. Several abiotic variables are of importance: light penetration, wave energy, current velocity, nutrients in substrate and physical characteristics of the substrate are controlling the species and their biomass. Field characterization of macrophytes was performed using echosounder transects in association with a submersible video camera. This technique allowed the calibration of each echofacies for species identification and their relative proportion, height and density. The main eleven assemblages appear to be strongly correlated with abiotic conditions. A basic interpretation key was set up in order to describe pla...

Lake Saint-Francois is a fluvial lake of the St. Lawrence system which is used for hydropower production and commercial navigation. For 150 years, it was dredged and dammed regularly without any impact analysis being made. The cumulative impact of dredging and damming on large rivers such as the St. Lawrence is an issue with only qualitative answers. Bidimensional hydrodynamics was used to simulate ancient flow conditions and to produce quantitative descriptors. Two Numerical Field Models (NFM) were prepared, one representing present state geometry, which contains 300,000 sounding points, and the other representing pristine state, based on 1900 and 1870 measurements and containing 70,000 soundings. These two NFMs were compared, showing important changes in the morphology of the lake. The NFMs were then used for bidimensional hydrodynamic simulations of both actual and pristine states for 3 different discharges: 5,000 m 3 /s, 7,500 m 3 /s, and 10,000 m 3 /s. Results highlight the cumulative physical transformation of the system. Hydrodynamic simulations and velocity differences show an increase of velocities over shoals for discharge under 8,800 m 3 /s, and a decrease of velocities in deeper water for the same range of discharge. Dredging and straightening around Cornwall Island resulted in changes from 64% to 71% of the total river flow passing through the south channel while the flow in the north channel decreased from 36% to 29%. These hydrodynamic transformations had a definitive impact on sedimentation and most probably on aquatic plant distribution.

A new finite element model has been developed to simulate two-dimensional free surface flow in rivers and estuaries. The variables of the model are the specific discharge and the water level. The algorithm takes into account the natural boundaries of the flow, defined by the contour lines of zero depth, with a new approach that accepts positive and negative values for the water depth. In this way, we consider a wet or dry area when the water depth is positive or negative respectively. A 6-node triangular element and an implicit Euler scheme are respectively used for spatial and time discretization of the mathematical model. The solution procedure is based on the inexact Newton-GMRES type solver with incomplete factorization as preconditioning. The numerical results of the proposed approach are in good agreement with an analytic solution and also with the classical approach.

Modifications to valley form due to extreme flooding in the lower 34 km of the Ha! Ha! River were analyzed. Heavy regional precipitation in July 1996 triggered extreme runoff and the catastrophic drainage of Ha! Ha! Lake, producing discharges of 1100 m3/s, 8 times the 100-year flood. Dominant valley modifications, revealed by comparing preflood and postflood topographies derived photogrammetrically, were related to two large-scale avulsions; in particular, a deep retrogressive incision which bypassed the 30-m-high Perron Falls, exporting 6 × 106 m3 of glacial stratified drift from a 2-km section of valley and producing massive sedimentation in the reach downstream. Reconstructed maximum flow power values support the existence of a 300 W/m2 threshold for major scouring of the alluvial valley bottom. The evidence highlights the potential for massive scour and fill and reorganization of the long profile, with potentially catastrophic effects on infrastructure, during extreme floods in glaciated valley settings.

SUMMARY A steady-state and transient finite element model has been developed to approximate, with simple triangular elements, the two-dimensional advection—di⁄usion equation for practical river surface flow simulations. Essentially, the space—time Crank—Nicolson—Galerkin formulation scheme was used to solve for a given conservative flow-field. Several kinds of point sources and boundary conditions, namely Cauchy and Open, were theoretically and numerically analysed. Steady-state and transient numerical tests investigated the accuracy of boundary conditions on inflow, noflow and outflow boundaries where di⁄usion is important (di⁄usive boundaries). With the proper choice of boundary conditions, the steady-state Galerkin and the transient Crank—Nicolson—Galerkin finite element schemes gave stable and precise results for advectiondominated transport problems. Comparisons indicated that the present approach can give equivalent or more precise results than other streamline upwind and high-order time-stepping schemes. Di⁄usive boundaries can be treated with Cauchy conditions when the flow enters the domain (inflow), and with Open conditions when the flow leaves the domain (outflow), or when it is parallel to the boundary (noflow). Although systems with mainly di⁄usive noflow boundaries may still be solved precisely with Open conditions, they are more susceptible to be influenced by other numerical sources of error. Moreover, the treatment of open boundaries greatly increases the possibilities of correctly modelling restricted domains of actual and numerical interest. ( 1997 by John Wiley & Sons, Ltd.

The SUPG/θ-method for applications in 2D advection–diffusion transport simulation is reviewed and it is presented in details. Spatial discretization is done with finite elements method with stabilized streamline upwind Petrov–Galerkin method, and time discretization was done with θ-stable finite difference operator. Numerical tests showed that this algorithm is general and robust and it can be applied to simulate simple problems of mass transport; for example, pure advection phenomenon in structured mesh, as well as reactive advection–diffusion transport with an unstructured mesh, and not well-behaved velocity field. The method was applied in a simulation of the transport of total phosphorus in the Lake Agua Preta, and the results were validated by comparison with experimental data. The computational cost is directly associated with the value of the safety factor, introduced to assure the stability of the method.

The principal goal of this papers is the development of numerical models to capture shock waves in compressible flows. In this first part we should only resolve the scalar convection equation. An explicit scheme for time discretization and FEM with linear triangular element for the space discretization should be employed. We have investigated two approaches. The first one, called the LWR method, is a centered sheme while the other one is the Fluctuation Splitting method based on an upwinding scheme. Initially, the second method was developed in a Finite Volume context, however we have rewriten it in a FE context by suitable choice of weighted functions. These methods are applied to different 2-D scalar convection equation examples.

Current paper’s main contribution includes hydrodynamic modeling and morphological analysis of lake Bolonha which, along with lake Água Preta, makes up the Utinga watershed in Belém, Pará State, Brazil. Bathymetry of lake Bolonha was undertaken by digitalizing the data provided by COSANPA (the local Sanitation and Water Supply Company) dating back to 1983, and from a 2007 field study. Both bathymetries produced two terrain elevation models which were used for morphological analysis and hydrodynamic simulations. The morphological analysis showed that between 1983 and 2007, no significant relief changes occurred on the bottom of lake Bolonha, except for the formation of the outflow channels between the interconnecting channel and Bolonha Water Treatment Plant (WTP). The hydrodynamic model was able to simulate depths and velocities. The velocities, ranging between 1.8 and 9.0 cm s-1, showed a subtle current between the outlet of the canal connecting the lakes Bolonha and Água Preta and the water intakes of the Bolonha and São Braz WTPs. This fact demonstrated that lake Bolonha reservoir is a passage for waters from lake Água Preta.

Submitted by Jairo Amaro (jairo.amaro@sibi.ufrj.br) on 2019-06-03T16:10:04Z No. of bitstreams: 1 4-2018_FLOW-ANALYSIS-AND-MODELING-OF-THE-LAKE_-min.pdf: 518720 bytes, checksum: efc8d561333afc5999dc7ae75f553a94 (MD5) Made available in DSpace on 2019-06-03T16:10:04Z (GMT). No. of bitstreams: 1 4-2018_FLOW-ANALYSIS-AND-MODELING-OF-THE-LAKE_-min.pdf: 518720 bytes, checksum: efc8d561333afc5999dc7ae75f553a94 (MD5) Previous issue date: 2012-04-12 Indisponível. The natural conditions of water resources can be modified with the unsustainable use of them. For example, in Belém, capital of Pará State, Água Preta Lake has a history of degradation jeopardize the drinking water supply in Belém. Thus, the main contribution of this work is to develop a study on modeling hydrodynamic study of Água Preta Lake. Such study is carried through the bathymetric of 2009 performed with an ADCP. The bathymetry and substrate data that composes the Lake and its boundary. The bathymetry data are used to construct the digital elevation model, with the coordinates x, y and z in UTM; while the composition of the substrate is used for the determination of the Manning coefficient. The coordinates x, y, z and Manning coefficient are used in the hydrodynamic model. This one is the classic model of Saint-Venant. In this case, a vertical integration is applied to the three-dimensional equations of Navier-Stokes for incompressible flow with outline conditions, of bottom and of liquid and solid surface, included. Thus, the problem becomes two-dimensional (2D) and the values obtained for velocities are medium in the vertical direction. The velocities are the input data for the many models, such as pollutant dispersion sediment transport and aquatic fauna and flora habitats. Thus,besides of hydrodynamic model explains the patterns of flow in the lake, it can be employed for the others models of the Lake Água Preta.

We have developed a new, stable and simple formulation, based on the MINI element, to integrate the compressible Navier-Stokes equations by the finite element method. This element is well suited for grid refinement. The non-linear system is solved by GMRES, an iterative method, coupled with a new diagonal preconditioning. The resulting algorithme is very efficient and vectorizes well. The element converges quadratically in the L2 norm and has been tested against results of the GAMM-Workshop on Compressible Navier-Stokes Flows, on regular grids as welt as on adapted grids.

We are interested to develop numerical solutions of problem A which concern the external 2D compressible viscous flow around a NACA-0012 airfoil, by the Galerkin Finite Element Method. A multi-mesh strategy coupled with a load increment is used.

L'article pose la problématique de la construction du Modèle Numérique de Terrain (MNT) dans le contexte d'études hydrauliques à deux dimensions, ici reliées aux inondations. La difficulté est liée à l'hétérogénéité des ensembles de données qui diffèrent en précision, en couverture spatiale, en répartition et en densité, ainsi qu'en géoréférentiation, notamment. Dans le cadre d'un exercice de modélisation hydrodynamique, toute la région à l'étude doit être documentée et l'information portée sur un support homogène. L'article propose une stratégie efficace supportée par un outil informatique, le MODELEUR, qui permet de fusionner rapidement les divers ensembles disponibles pour chaque variable qu'elle soit scalaire comme la topographie ou vectorielle comme le vent, d'en préserver l'intégrité et d'y donner accès efficacement à toutes les étapes du processus d'analyse et de modélisation. Ainsi, quelle que soit l'utilisation environnementale du modèle numérique de terrain (planification d'aménagement, conservation d'habitats, inondations, sédimentologie), la méthode permet de travailler avec la projection des données sur un support homogène de type maillage d'éléments finis et de conserver intégralement l'original comme référence. Cette méthode est basée sur une partition du domaine d'analyse par type d'information : topographie, substrat, rugosité de surface, etc.. Une partition est composée de sous-domaines et chacun associe un jeu de données à une portion du domaine d'analyse par un procédé déclaratoire. Ce modèle conceptuel forme à notre sens le MNT proprement dit. Le processus de transfert des données des partitions à un maillage d'analyse est considéré comme un résultat du MNT et non le MNT lui-même. Il est réalisé à l'aide d'une technique d'interpolation comme la méthode des éléments finis. Suite aux crues du Saguenay en 1996, la méthode a pu être testée et validée pour en démontrer l'efficacité. Cet exemple nous sert d'illustration., This article exposes the problem of constructing a Numerical Terrain Model (NTM) in the particular context of two-dimensional (2D) hydraulic studies, herein related to floods. The main difficulty is related to the heterogeneity of the data sets that differ in precision, in spatial coverage, distribution and density, and in georeference, among others. Within the framework of hydrodynamic modelling, the entire region under study must be documented and the information carried on a homogeneous grid. One proposes here an efficient strategy entirely supported by a software tool called MODELEUR, which allows to import, gather and merge together very heterogeneous data sets, whatever type they are, scalar like topography or vectorial like wind, to preserve their integrity, and provide access to them in their original form at every step of the modelling exercise. Thus, whatever the environmental purpose of the modelling exercise (enhancement works, sedimentology, conservation of habitats, flood risks analysis), the method allows to work with the projection of the data sets on a homogeneous finite element grid and to conserves integrally the original sets as the ultimate reference. This method is based on a partition of the domain under study for each data type: topography, substrates, surface roughness, etc. Each partition is composed of sub-domains and each of them associates a data set to a portion of the domain in a declarative way. This conceptual model represents formally the NTM. The process of data transfer from the partitions to the final grid is considered as a result of the NTM and not the NTM itself. It is performed by interpolation with a technique like the finite element method. Following the huge Saguenay flood in 1996, the efficiency of this method has been tested and validated successfully and this example serves here as an illustration.The accurate characteristics description of both river main channel and flood plain is essential to any hydrodynamic simulation, especially if extreme discharges are considered and if the two-dimensional approach is used.The ground altitude and the different flow resistance factors are basic information that the modeler should pass on to the simulator. For too long, this task remained "the poor relative" of the modeling process because it does not a priori seem to raise any particular difficulty. In practice however, it represents a very significant workload for the mobilisation of the models, besides hiding many pitfalls susceptible to compromise the quality of the hydraulic results. As well as the velocity and water level fields are results of the hydrodynamic model, the variables describing the terrain and transferred on the simulation mesh constitute the results of the Numerical Terrain Model (NTM). Because this is strictly speaking a modeling exercise, a validation of the results that assess the quality of the model is necessary.In this paper, we propose a methodology to integrate the heterogeneous data sets for the construction of the NTM with the aim of simulating 2D hydrodynamics of natural streams with the finite element method. This methodology is completely supported by a software, MODELEUR, developed at INRS-Eau (Secretan and Leclerc, 1998; Secretan et al., 2000). This tool, which can be assimilated to a Geographical Information System (GIS) dedicated to the applications of 2D flow simulations, allows to carry out all the steps of integrating the raw data sets for the conception of a complete NTM. Furthermore, it facilitates the application and the piloting of hydrodynamic simulations with the simulator HYDROSIM (Heniche et al., 1999).Scenarios for flow analysis require frequent and important changes in the mesh carrying the data. A return to the basis data sets is then required, which obliges to preserve them in their entirety, to have easily access to them and to transfer them efficiently on the mesh. That is why the NTM should rather put emphasis on basic data rather than on their transformed and inevitably degraded aspect after their transfer to a mesh.The data integrity should be preserved as far as possible in the sense that it is imperative to keep distinct and to give access separately to different data sets. Two measuring campaigns will not be mixed; for example, the topography resulting from digitised maps will be maintained separated from that resulting from echo-sounding campaigns. This approach allows at any time to return to the measures, to control them, to validate them, to correct them and possibly, to substitute a data set a by another one.The homogeneity of the data support with respect to the location of the data points is essential to allow the algebraic interaction between the different information layers. The operational objective which bear up ultimately the creation of the NTM in the present context is to be able to transfer efficiently the spatial basic data (measurements, geometry of civil works, etc.) each carried by diverse discretisations towards a single carrying structure.With these objectives of integrity, accessibility, efficiency and homogeneity, the proposed method consists of the following steps:1. Import of the data sets into the database, which possibly implies to digitise maps and/or to reformat the raw files to a compatible file format; 2. Construction and assembly of the NTM properly which consists, for each variable (topography, roughness, etc.), to create a partition of the domain under study, that is to subdivide it into juxtaposed sub-domains and to associate to each sub-domain the data set which describes the variable on it. More exactly, this declaratory procedure uses irregular polygons allowing to specify in the corresponding sub-domains the data source to be used in the construction of the NTM. As it is also possible to transform regions of the domain with algebraic functions to represent for example civil works in river (dikes, levees, etc.), the NTM integrates all the validated data sets and the instructions to transform them locally. From this stage, the NTM exists as entity-model and it has a conceptual character;3. Construction of a finite element mesh;4. Transfer by interpolation and assembly of the data of the different components of the NTM on the finite element mesh according to the instructions contained in the various partitions. The result is an instance of the NTM and its quality depends on the density of the mesh and the variability of the data. So, it requires a validation with respect to the original data;5. Realisation of the analysis tasks and/or hydrodynamic simulations. If the mesh should be modified for a project variant or for an analysis scenario, only tasks 3 and 4 are to be redone and task 4 is completely automated in the MODELEUR.The heterogeneity of the data sources, which constitutes one of the main difficulties of the exercise, can be classified in three groups: according to the measuring technique used; according to the format or the representation model used; according to the geographic datum and projection system.For the topography, the measuring techniques include conventional or radar satellite, airborne techniques, photogrammetry or laser scanning, ground techniques, total station or GPS station, as well as embarked techniques as the echo-sounder. These data come in the form of paper maps that have to be digitised, in the form of regular or random data points, isolines of altitude, or even as transects. They can be expressed in different datums and projections and sometime are not even georeferenced and must be first positioned.As for the bed roughness that determines the resistance to the flow, also here the data sets differ one from the other in many aspects. Data can here also have been picked as regular or random points, as homogeneous zones or as transects. Data can represent the average grain size of the present materials, the dimension of the passing fraction (D85 or D50 or median), the represented % of the surface corresponding to every fraction of the grain assemblage, etc... In absence of this basic data, the NTM can only represent the value of the friction parameter, typically n of Manning, which should be obtained by calibration for the hydrodynamic model. For the vegetation present in the flood plain or for aquatic plants, source data can be as variable as for the bed roughness. Except for the cases where data exists, the model of vegetation often consists of the roughness parameter obtained during the calibration exercise. The method was successfully applied in numerous contexts as demonstrated by the application realised on the Chicoutimi River after the catastrophic flood in the Saguenay region in 1996. The huge heterogeneity of the available data in that case required the application of such a method as proposed. So, elevation data obtained by photogrammetry, by total station or by echo-sounder on transects could be coordinated and investigated simultaneously for the purposes of hydrodynamic simulation or of sedimentary balance in zones strongly affected by the flood.

This paper describes a set of field data suitable for the testing and comparative assessment of geomorphic flood routing methods. The data pertain to a particularly severe and unusually well–documented flood event: the Lake Ha! Ha! breakout flood of July 1996 in the Saguenay Region of Quebec. In this event, heavy rains combined with the incision of a new lake outlet caused a major flood, which significantly reworked the downstream valley. Published and unpublished data from multiple sources are assembled and co–registered in a common frame of reference. These data include vertical and oblique air photos, hydrological records, surface geology information, and digital terrain models of the pre– and post–flood valley topography. The spatial coverage encompasses the drained lake as well as the full length of the downstream valley. To meet the respective needs of two– and one–dimensional approaches, the topography is sampled on a Cartesian mesh as well as interpolated along evenly–spaced cross–sections. The da...

Actuellement, en considérant simultanément les éléments constitutifs du risque, soit l'aléa et la vulnérabilité, aucune des méthodes existantes dites de cartographie des risques d'inondation ne permet d'établir de façon précise et quantifiable en tous points du territoire les risques d'inondation. La méthode de cartographie présentée permet de combler ce besoin en répondant aux critères suivants : facilité d'utilisation, de consultation et d'application, résultats distribués spatialement, simplicité de mise à jour, applicabilité à divers types de résidences.La méthode présentée utilise une formulation unitaire du risque basée sur les taux d'endommagement distribués et reliés à diverses périodes de retour de crues à l'eau libre. Ceux-ci sont d'abord calculés à partir des hauteurs de submersion qu'on déduit de la topographie, des niveaux d'eau pour des périodes de retour représentatives et du mode d'implantation des résidences (présence de sous-sol, hauteur moyenne du rez-de-chaussée). Ensuite, le risque unitaire est obtenu par intégration du produit du taux d'endommagement croissant par son incrément de probabilité au dépassement. Le résultat est une carte représentant le risque en % de dommage direct moyen annuel. Une étude pilote sur un tronçon de la rivière Montmorency (Québec, Canada) a montré que les cartes sont expressives, flexibles et peuvent recevoir tous les traitements additionnels permis par un SIG tel que le logiciel MODELEUR/HYDROSIM développé à l'INRS-ETE, l'outil utilisé pour cette recherche. Enfin, l'interprétation sur la Montmorency des cartes d'inondation en vigueur actuellement au Canada (les limites de crue de 20/100 ans) soulève des interrogations sur le niveau de risque actuellement accepté dans la réglementation, surtout quand on le compare aux taux de taxation municipale., Public managers of flood risks need simple and precise tools to deal with this problem and to minimize its consequences, especially for land planning and management. Several methods exist that produce flood risk maps and help to restrict building residences in flood plains. For example, the current method in Canada is based on the delineation in flood plains of two regions corresponding to floods of 20- and 100-year return periods (CONVENTION CANADA/QUÉBEC, 1994), mostly applied to ice-free flooding conditions. The method applied by the Federal Emergency Management Agency FEMA (2004) is also based on the statistical structure of the floods in different contexts, with a goal mostly oriented towards the determination of insurance rates. In France, the INONDABILITÉ method (GILARD and GENDREAU, 1998) seeks to match the present probability of flooding to a reduced one that the stakeholders would be willing to accept.However, considering that the commonly accepted definition of risk includes both the probability of flooding and its consequences (costs of damages), very few, if any of the present methods can strictly be considered as risk-mapping methods. The method presented hereafter addresses this gap by representing the mean annual rate of direct damage (unit value) for different residential building modes, taking into account the flood probability structure and the spatial distribution of the submersion height, which takes into account the topography of the flood plain and the water stage distribution, the residential settlement mode (basement or not) and the first floor elevation of the building. The method seeks to meet important criteria related to efficient land planning and management, including: ease of utilisation, consultation and application for managers; spatially distributed results usable in current geographical information systems (GIS maps); availability anywhere in the area under study; ease of updating; and adaptability for a wide range of residence types.The proposed method is based on a unit treatment of the risk variable that corresponds to a rate of damage, instead of an absolute value expressed in monetary units. Direct damages to the building are considered, excluding damages to furniture and other personal belongs. Damage rates are first computed as a function of the main explanatory variable represented by the field of submersion depths. This variable, which is obtained from the 2D subtraction of the terrain topography from the water stage for each reference flood event, is defined by its probability of occurrence. The mean annual rate of damage (unit risk) is obtained by integrating the field of damage rate with respect to the annual probability structure of the available flood events. The result is a series of maps corresponding to representative modes of residential settlement.The damage rate was computed with a set of empirical functional relationships developed for the Saguenay region (Québec, Canada) after the flood of 1996. These curves were presented in LECLERC et al. (2003); four different curves form the set that represents residences with or without a basement, with a value below or above $CAD 50,000, which is roughly correlated with the type of occupation (i.e., secondary or main residence). While it cannot be assumed that theses curves are generic with respect to the general situation in Canada, or more specifically, in the province of Québec, the method itself can still be applied by making use of alternate sets of submersion rates of damage curves developed for other specific scenarios. Moreover, as four different functional relationships were used to represent the different residential settlement modes, four different maps have to be drawn to represent the vulnerability of the residential sector depending of the type of settlement. Consequently, as the maps are designed to represent a homogeneous mode of settlement, they represent potential future development in a given region better than the current situation. They can also be used to evaluate public policies regarding urban development and building restrictions in the flood plains.A pilot study was conducted on a reach of the Montmorency River (Québec, Canada; BLIN, 2002). It was possible to verify the compliance of the method to the proposed utilisation criteria. The method proved to be simple to use, adaptive and compatible with GIS modeling environments, such as MODELEUR (SECRETAN at al, 1999), a 2D finite elements modeling system designed for a fluvial environment. Water stages were computed with a 2D hydrodynamic simulator (HYDROSIM; HENICHE et al., 1999a) to deal with the river reach complexity (a breaded reach with back waters). Due to the availability of 2D results, a 2D graphic representation of the information layers can therefore be configured, taking into account the specific needs of the interveners. In contexts where one dimensional water stage profiles are computed (e.g., HEC-RAS by USACE, 1990; DAMBRK by FREAD, 1984), an extended 2D representation of these data needs to be developed in the lateral flood plains in order to achieve a 2D distributed submersion field.Among the interesting results, it was possible to compare the risk level for given modes of settlements (defined by the presence/absence of a basement and the elevation of the first floor with respect to the land topography) with current practices, based only on the delineation of the limits of the flood zones corresponding to 20/100 year return periods. We conclude that, at least in the particular case under study, the distributed annual rate of damage seems relatively large with respect to other financial indicators for residences such as urban taxation rates.