Route or convolute?

Some of the conceptual hydrograph models for routing rainfall excess through a cascade of linear reservoirs have been reexamined. Because of the linearity of these models, convolution of the instantaneous unit hydrograph (IUH) is mathematically identical to synthetic hydrographs obtained by direct routing. Routing, however, has been a more traditional procedure mainly because the mathematics is much simpler and the solution of synthetic hydrographe is more direct. Also, reduction of storm duration in the IUH approach has significant disadvantages. If one chooses a linear cascade model for hydrograph synthesis, direct routing in the traditional sense is more direct, more informative, less tedious, and much less time consuming, and it permits sensitivity analysis of the model parameters as computational trials progress and accomplishes convolution implicitly.