The Sub-Himalayan Zone constitutes a tectonic wedge of synorogenic sediments along the southern edge of the Himalayan Belt. Sediments are incorporated into the prism from the foreland Indo-Gangetic plain, undergo a tectonic cycle within it, and eventually are eroded. The structural sketch map exhibits westward-plunging arcuate structures on the foremost location of the Outer Belt. Investigations from spatial imagery and digital elevation modeling (DEM), together with kinematic data, allow us to calculate velocities for the geomorphologic development. Four velocities rule the general evolution of the wedge. The foremost geomorphic structure (ridge) is the assemblage of elementary structures. The lateral ridge propagation velocity is estimated to be 40 cm/yr, which supports a general cylindrical development of the Outer Belt, in spite of the asymmetrical development of each independent elbow-shaped structure. The sediment's burial history can be quantified from geometric and kinematic data. We emphasize that because of the cylindrical behavior of the prism, extrapolation of the sediment transfer to the entire western Nepal Siwalik is valid. Burial in the foreland basin takes two times longer than the entire tectonic cycle, which only lasts for about 6.5 m.y. Sediments reaching 6 10⁵ km³ per year and per linear kilometer accrete along the Siwalik range. About 21% of the flowing material within the wedge is captured and withdrawn from it as subducted duplexes. Assuming a steady-state development of the wedge, and according to the Coulomb-wedge theory for the Siwalik, mean erosion rates are estimated to be about 1.9 mm/yr, which is in accord with previous estimates. We emphasize that this consistency supports the overall estimates for the general development of the wedge.