DISCHARGE RESPONSE ANALYSIS AND HYDROLOGIC SIMILARITY - INTERRELATION BETWEEN THE GEOMORPHOLOGIC IUH AND THE STORM CHARACTERISTICS

It is shown that the dynamic parameter v of the geomorphologic instantaneous unit hydrograph (IUH) can be taken as the velocity at the peak discharge time for a given rainfall‐runoff event in a basin. This transforms the time variant IUH throughout the event into a time invariant IUH in each storm occurrence. The errors which the a priori estimation of the velocity in the IUH may cause in the calculation of the peak and time to peak of the runoff discharge are estimated for different types of basins and storms; the relative weights of the storm characteristics and the drainage network parameters in the prediction procedure are also studied in detail. Drainage basins are defined as hydrologically similar if they have the same IUH when kinematic conditions are kept the same; through the geomorphologic IUH theory it is shown that the controlling parameter in hydrologic similarity is RL0.43/LΩ. Copyright 1979 by the American Geophysical Union.