Computation of weighting factor x for development of unit hydrograph

摘要

The present paper outlines a strategy for computation of weighting factor (x) to compute the peak discharge for a given rainfall runoff event in a basin. The time invariant instantaneous unit hydrograph (IUH) was converted into unit hydrograph (UH) for each storm event. The peak and time to peak of runoff discharge were estimated for different storms of the basin by: convolution of UH with rainfall excess (Re). The relative weights of the storm characteristics and basin parameters were also used in the prediction of peak. The Chaukhutia watershed of Ramganga river catchment was selected to check the predicted results with respect to observed direct runoff hygrographs (DRHs). The value of quantitative parameter like; coefficient of efficiency (0.7340), departure percentage (0.1837) and the value of absolute relative error (3.7254) were used to compute the appropriate value of the weighting factor x. The theory provided excellent agreement for the Chaukhutia watershed of Ramganga river of Uttarakhandbasin (452 km~2) area at the x value of 0.30.