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Water supply watershed planning and management: an integrated approach

Deliverables

ESIMEAU Integrated Information System for Modelling and Management of Water Resources: Concept and Architecture, J. of Systems Analysis Modelling Simulation - SAMS, Vol. 40, pp. 669-688, 2001. This paper addresses the concept and architecture of ESIMEAU, an integrated information system for modelling and management of water resources. ESIMEAU has been designed to provide a framework that permits users to implement it in various water modelling. It brings together a variety of information technology tools including advanced numerical models, database management systems, and geographic information technology. In this paper the general framework of ESIMEAU is discussed as well as the application of this framework to study the eutrophication problem in the Bouregreg lake in Morocco.
We present a mixed finite element method to solve numerically the two dimensional Quasi­ Stokes equations. The aim is to use this method as a basic solver for the unsteady Navier­Stokes equations; to linearize these Navier­Stokes equations, the total derivative term of the velocity is treated with a first order characteristics method. The unknowns of the mixed Quasi­Stokes formulation are the vorticity and the stream function discretized by piecewise continuous functions. As well known a direct approach leading to the loss of one order in the error estimates, we use a regularization stabilization technique by adding a new discrete form in the formulation. This new formulation remains consistent and is inconditionaly convergent. Moreover, in case of sufficient regularity on the vorticity, we get an O(h) optimal error estimate. Numerical tests confirm the results announced in this theoretical part.
We describe a numerical approximation of a two phase water­air bubbles flow in the case of a water reservoir aeration process. Using characteristics method for time discretization, a two phase Quasi­Stokes type problem is derived. The well­posedness of this problem and its approximation by a mixed finite element method are proved. Error estimates between the exact and discrete solutions and a study of the time dependent problem are given. Numerical tests are presented in order to illustrate this method.
A virtual numerical simulator for aeration effects in lake eutrophication, Submitted to International Journal of Computational Fluid Dynamics, Vol 16-2, pp. 119-128, 2002. In this paper, the eutrophication process in reservoirs is briefly presented, then one of the best remedial actions against it, i.e. aeration, is developed. Multiphase flows are then described to show the complexity of the process and related modelling issues. A first order approximation is then suggested through one-phase flow analysis based on the conventional Navier-Stokes equations to simulate virtually aeration effects in natural reservoirs or lakes by prescribing appropriate internal conditions for velocity to simulate air injection. Though the flow features three-dimensional aspects with variable density, only two-dimensional incompressible fluid flow configurations are considered in this paper to demonstrate the feasibility of the methodology developed. Numerical experiments are then run for scenario analysis. Though the results are somewhat qualitative, they are encouraging and with some kind of validation and calibration a cheap alternative can be offered for studying the aeration process.