Journal of Environmental Hydrology
ISSN 1058-3912


Electronic Journal of the International Association for Environmental Hydrology
JEH Volume 18 (2010), Paper 7    Posted April 30, 2010
IMPROVED HORTON-STRAHLER SCHEME FOR STREAM NETWORK CLASSIFICATION AND ITS IMPLEMENTATION IN THE METHOD OF GEOMORPHOLOGIC INSTANTANEOUS UNIT HYDROGRAPH

Gordan Prskalo

Faculty of Civil Engineering, University of Mostar, Mostar, Bosnia and Herzegovina
ABSTRACT
The Horton-Strahler scheme for stream network classification was introduced into hydrological practice in the middle of the last century. It found a significant application in the process of defining the Geomorphologic Instantaneous Unit Hydrograph (GIUH) as the method aiming to relate geomorphological characteristics of a basin to basin response in the form of unit hydrograph, or direct runoff hydrograph. The paper analyzes the problems related to its implementation in the GIUH method, i.e. to determination of initial and transition probabilities, which, in turn, are used to define the probability distribution function for water flow paths in the basin. Many authors have agreed that this classification is rather rough and in some cases leads to certain irregularities, i.e. inaccuracies. The particular problem is that negative values may also result when calculating initial and transition probabilities at higher stream orders. In this regard, the so-called Improved Horton-Strahler Scheme (IHSS) for classification of the hydrographic network has been proposed in the paper. The basic idea is that streams and hillslopes are classified in groups or orders according to flow paths. Thus, we avoided the averaging or uniform distribution of numbers and lengths of streams and hillslope areas to a number of flow paths, as is the case with the original Horton-Strahler scheme. The improved Horton-Strahler Scheme was applied to the catchment of the Brijesnica River in Bosnia and Herzegovina and the relevant unit hydrographs were calculated using the GIUH method.
Reference: Prskalo, G. 2010. Improved Horton-Strahler scheme for stream network classification and its implementation in the method of geomorphologic instantaneous unit hydrograph. Journal of Environmental Hydrology, Vol. 18, Paper 7.
CONTACT:
Gordan Prskalo
Faculty of Civil Engineering
University of Mostar
Matice Hrvtaske bb
Mostar, Bosnia and Herzegovina

E-mail: gordan.prskalo@tel.net.ba


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