A reduced strongly nonlinear model is derived for the evolution of one-dimensional
internal waves over an arbitrary bottom topography. Two layers containing inviscid, immiscible,
irrotational fluids of different densities are defined. The upper layer is shallow compared with the
characteristic wavelength at the interface, while the bottom region’s depth is comparable to the
wavelength. The nonlinear evolution equations obtained are in terms of the internal wave elevation
and the mean upper-velocity for the configuration described. The system is a generalization of the
one proposed by Choi and Camassa for the flat bottom case in the same physical settings. Due to the
presence of a topography a variable coefficient system of partial differential equations arises. These
Boussinesq-type equations contain the Intermediate Long Wave (ILW) equation and the Benjamin-
Ono (BO) equation when restricted to the unidirectional propagation regime. We intend to use
this model to study the interaction of waves with the bottom profile. The dynamics include wave
scattering, dispersion and attenuation, among other phenomena.