Synthetic Unit Hydrograph Methods: A Critical Review

The present study critically reviews the synthetic unit hydrograph (SUH) methods available in hydrologic lit- erature. The study reveals that the traditional methods of SUH derivation, e.g., Snyder, SCS, traditional methods like Sny- der and TS method that does not yield satisfactory results, and their application to the practical engineering problems is tedious and combursome. On the other hand, probability distribution functions (pdfs) based SUH methods are easy to ap- ply, and easily meet the UH criterion, i.e. the area under the curve is unity, and rely on a stronger mathematical base and sounder hydrologic perception. The recent pdfs used for deriving UHs in ungauged catchments, address the SUH shapes with more flexibility than the earlier pdfs proposed by (1) for SUH derivation.