Application of adjoint method for estimating Manning-Strickler coefficient in Tondi Kiboro catchment

In this paper, an adjoint method for estimating the well-known Manning-Strickler coefficient is developed and applied on a Sahelian catchment called Tondi Kiboro. The dynamics of overland flow are firstly got from the continuity equation of Saint-Venant model via some appropriate assumptions. The infiltration process is also considered and described by Green-Ampt equation. Lagrange method is used to connect the measured discharge of the flow to the dynamics of the system. The gradient of Lagrangian augmented cost functional with respect to Manning coefficient is obtained by adjoint analysis and used in optimization process. A numerical implementation on Tondi Kiboro basin is provided as a practical application example. After the optimization process, the estimated value of Manning coefficient is finally validated with another data set of overland flow on Tondi Kiboro basin.