The acoustic reflection coefficient for a solid ocean bottom can be well approximated by assuming an ‘‘equivalent fluid’’ bottom of suitably chosen parameters. The density and attenuation of the equivalent fluid are different from the corresponding parameters of the solid. In particular, the density is substantially smaller and it is shown that simple neglect of the shear wave parameters of the solid can give poor results. The equivalent fluid can be used for both normal mode and ray calculations of the field in the water and gives essentially the same results as calculations that include the full shear waves effects. For isovelocity water, bottom reflection can also be modeled by assuming a perfect reflector at an ‘‘effective depth.’’ A new complex effective depth is defined to account for energy loss due to attenuation and the generation of shear waves. The resulting normal mode parameters are also complex. The sound field in shallow isovelocity water can be found very accurately and rapidly using the complex effective depth approach.