A portable integrated rainfall and overland flow simulator

This paper describes a prototype of a portable rainfall simulator that can simulate a wide range of rainfall intensities with a kinetic energy similar to that of natural rainfall and, more innovatively, provide simultaneous or independent simulations of rainfall and overland flow at the microplot scale (0.70 m(2)). The design of the rotating shutter disc makes possible a wide range of rainfall intensities, from 30 to 155 mm/h without changing nozzle type or working pressure. Overland flow intensity can be adjusted from 94 to 573 mm/h depending on nozzle type and working pressure. The flow is applied on the upper side of the experimental plot. The Christiansen coefficient of uniformity of the simulated rainfall varied between 81.4 and 85.1%, and the calculated kinetic energy was > 90% the kinetic energy of corresponding natural rain. Special attention was paid to portability. Stainless steel was used whenever possible and the equipment was constructed in modules so that it could easily be dismantled and carried by two people. A telescopic-type frame allows operation on sloping ground.