The purpose of this paper is to investigate the identification of the water depth and the water velocity potential in a coastal region by using the linearized water wave equation (LWWE). Existence and uniqueness of the solutions to the partial differential equation LWWE are shown by using the semigroup theory. Moreover the analytical solution is found by the separation of variables method. We assume that the surface wave elevation is measurable. We like to recover the water depth and the water velocity potential from the measurement. This identification problem is shown to be well-posed by proving the parameters' identifiability by the surface elevation. Based on the classical gradient descent method we elaborate an identification algorithm to recover simultaneously both the water depth and the velocity potential. Numerical simulations are carried out to illustrate effectiveness of the algorithm. through the mathematical model of water waves and measuring the surface wave elevation.The water wave equation consists in describing the motion of the water waves occupying a domain delimited below by a fixed bottom and by a free surface above. To write down the water wave equation, let Ω t = {(x, z) ∈ R + × (−h, η(x, t)) } denote the water domain in 2-dimensional euclidian framework as illustrated in Fig.??, where R + = [0, ∞), η(x, t) is the surface elevation of water wave at position x and time t, and h the water depth. We assume that the water and the water waves satisfy the following assumptions: (A1) The water is incompressible ; (A2) There is no surface tension and the water is inviscid; (A3) The water particles do not cross the bottom and the surface; (A4) The external pressure is constant; (A5) The seabed is flat, so that h is positive constant; (A6) The water wave is irrotational. Since the irrotational assumption has been made, consequently there exists a flow potential φ = φ(x, z, t) such that the velocity field V is written by V = (φ x , φ z ) T , where φ x , φ z denote the partial derivative of φ with respect to x and to z, respectively. Thus, the mass conservation is expressed by the Laplace equationwith the boundary condition at the bottom φ z = 0, on z = −h.The Neumann condition (2) means that at the bottom of seabed, the normal component of the velocity is zero. The dynamical and kinematical boundary conditions on the free surface are