Grijm (1961) studied delta formation from rivers discharging sand. The sand transport rate was set to be proportional to twice the incident breaking-wave angle to the shoreline. Two different analytical solutions were presented: one for which the incident breaking wave angle and the shoreline orientation angle were small and one for which the wave angle was small in comparison with the shoreline orientation. The governing equations, i.e. sand transport and mass conservation equation, were expressed in polar coordinates and solved numerically. Grijm (1965) further developed this technique and presented solution for a wide range of delta formations.