The invention is a method of modeling a hydrocarbon reservoir. A parameter value in a set of equations is adjusted so that the output of the equations accurately matches observed sediment erosion and deposition behavior for sediment sizes throughout a range of about 10 microns to about 10 centimeters. An initial condition of a sediment bed in the hydrocarbon reservoir is defined. The equations are applied to the initial condition, wherein outputs of the equations express how a fluid flow affects erosion and deposition of sediments at the initial condition. The initial condition is adjusted based on the equation outputs to create a subsequent sediment bed condition. The equations are re-applied to the subsequent sediment bed condition a pre-determined number of times. The subsequent sediment bed condition is re-adjusted after each re-application of the equations. The model of the hydrocarbon reservoir is created and outputted.