Abstract:
Two parameter gamma probability density function (pdf) is one of the most commonly used representation of instantaneous unit hydrograph (IUH) of a basin. Parameter estimation is a major constraint for its application on ungauged catchments or catchments with limited data. When sufficient records are not available, one of the possibilities is the development of a relationship between characteristics of quantitative geomorphology of drainage basins and channel networks and parameters of an IUH. Recent advances in geomorphological parameterization and their linking to the parameters of existing conceptual hydrological models provides a good basis for application of these models to ungauged catchments. In this report, a methodology to derive the gamma pdf parameters is proposed using dimensionless Horton numbers, and characteristic stream flow velocity which in turn is estimated from basin lag calculated from basin area. The applicability of the proposed method has been tested by simulation runs using data for four sub-basins of river Narmada namely Narmada at Manot, Burhner at Mohegaon, Banjar at Hridenagar and Sher at Belkheri. The results of simulation are in reasonable agreement with observed records.
