This technical note describes the design, construction, and initial use of a complete physical model of the rainfall-surface runoff process. The complete physical model consists basically of a rainfall generator, scaled model, and a weighing device for recording the model runoff. The rainfall generator features individually-controlled modules which use small tubes as the drop formers. Initial tests indicate feasibility of the facility, illustrate its limitations, and point to areas where additional features would be useful. It is shown that the rainfall-surface runoff process can, in fact be modelled physically with reasonable precision, and various means of improving this accuracy of prediction for future tests are suggested.