Improvement of Snyder's Method for Synthetic Unit Hydrograph

Snyder's method of synthetic unit hydrograph (SUH) uses a few points on a unit hydrograph (UH) to manually sketch a smooth curve, the area under which is to be unity. A great degree of subjectivity and labor is involved to get a SUH, therefore the dimensionless UH of Nash model has been used to remove these errors from manual sketching of the UH. Simple methods have been proposed for Snyder's SUH which gives a smooth shape to the unit hydrograph, the area under which automatically satisfies the unit volume constraint. The parameters of the UH have been derived on the 4 cases for the (1) , (2) , (3) and , (4) peak discharge , which are the widths of and of the UH in hours at 50% and 75% height of the peak flow ordinate respectively. Application of the proposed methods have been illustrated through 4 sites. It was observed that the cases of (3) and (4) reflect Snyder's SUH most, and the use of is more resonable for the flood prediction.