The industrial system Telemac2D, developed by LNHE-EDF and commercialized by Sogreah Co., is an software dedicated to the hydrodynamical and environmental modelling of maritime and river flows. It is based on finite element method and is written in Fortran 90. Our final objective is to include a full variational data assimilation process in the system. This requires the development of an adjoint model. We plan to obtain it using the Automatic Differentiation (AD) tool Tapenade v2.0. In this study, we prepare and validate a reduced version of Telemac2D that is both meant for river flows and suitable to Tapenade v2.0. Then, we establish a strategy of AD according to limitations of the current release of Tapenade (v2.0). Also, the optimization chain is achieved thanks to the unconstrained minimizer N1QN3 based on a quasi-Newton type method. The final objective is to exploit the fluvial measurements and observations in an optimal manner in Telemac2D, in order to identify the partially known or lacking parameters (bathymetry, bed friction, inflow discharge and initial state).