Determining Soil Parameters

The problem of determining soil parameters is considered. Their exact knowledge is of great importance for planning and managing water systems, assessing the possible size of catastrophic floods, etc. These parameters are proposed to be found by solving some optimal control problem, where the controlled process is described by the Richards equation. The objective function is mean-square deviation of the observed soil moisture values from its simulated values, which are obtained from the solution of the Richards equation with the selected parameters values. Numerical optimization is performed using Newton method. Derivatives of the objective function are calculated using fast automatic differentiation techniques.