The article discusses how scientists predict overland flow hydrographs using mathematical models in laboratory experiments. They found that the time to peak, peak value, and total time base of the hydrograph depend on rainfall intensity. Using a convolution integral to predict runoff gives incorrect results, but the kinematic wave model provides accurate predictions. The time to equilibrium predicted by the model correlates well with empirically determined values. The relationship between rainfall and runoff is nonlinear and not affected by the slope or roughness of the surface.