Parameter estimation of a real hydrological system using an adjoint method*

This paper deals with the problem of parameter estimation in a real hydrological catchment of Niger, including Manning roughness and Horton infltration coefcients. Firstly, the dynamics of water fow on this catchment are modeled by using the continuity equation of Saint-Venant and the Horton infltration model whose the parameters are supposed to be unknown. The estimation approach is then based on the calculus of variations which is applied on a Lagrangian objective functional, in order to get the gradients of this functional with respect to parameters needing to be estimated. These gradients are used as inputs of a quasi-Newton optimization algorithm to solve the estimation problem. The presented approach is implemented with real data of the Niger catchment called Tondi Kiboro to get the desired values of parameters.