An Invesntigation of Instantaneous Peak Geomorphologic and Geomorphoclimatic Unit and Gray Hydrographs Ability in Navrood Watershed

The study of relations between morphologic characteristics of basins and their hydrologic response is one of the important issues in the science of hydrology. Geomorphologic instantaneous unit hydrograph (G.LU.H) and Geomorphoclimatic instantaneous unit hydrograph (GcJ.U.H) and GRAY
unit hydrograph are some results of the efforts in this field in order to evaluate the efficiency of these models in determination of the shape and ordinates of direct runoff hydrograph, Navrood representative basin in southwest ledge of Caspian Sea in west of Gillan Province was considered.
Database of 6 events of rainfall-runoff in non-melting seasons was collected. Ordinate of unit
hydrograph and direct runoff hydrograph were calculated by using the above models for selected events, separately. The results show that G.LU.H and Gc.LU.H models in comparison with GRAY model are better fit for use in determination of peak discharge in direct runoff hydrograph but there is no significant difference among them in determination of time to peak, base time and volume of direct runoff. In addition, Gc.LU.Hmodel in comparison with GJ.U.H is of a higher efficiency for determination of the ordinates of direct- runoff hydrograph especially in cases with less peak discharge