RELATIONS AMONG WATER DISCHARGE, LENGTH OF NETWORK AND TOTAL NUMBER OF STREAM SEGMENTS IN DRAINAGE BASINS

Ion Zăvoianu

University Spiru Haret, Faculty of Geography, Bucharest, Romania

Abstract

For all causality relations between morphometric variables and the elements of water regime, the number of stream segments and total stream length in the Horton-Strahler system have been overlooked. The aim of the present paper is to verify whether a dependence relation between these variables and water discharge does exist. To this end, determinations have targgeted the drainage model of the law of number of stream segments and the law of summed length by order of magnitude, eventually making a total by basin. The data-base, which contains the values of the Bârlad drainage system, its sub-basins and of representative basins in Romania has been used to correlate the values found in normal and logarithmic co-ordinates. The Bârlad basin case-study has produced good quantitative relations because differences in the geographical conditions that generate water discharge within this space are rather small. In order to establish the extent to which these relations are applicable to the whole Romanian territory, the number and length of stream segments in the Horton-Strahler classification system were determined at the water-gauge stations of representative basins situated in various landform units. In this case, too, the correlation of values in log-log coordinates indicates dependence relations, but looking at the value display it appears that a third variable, or group of variables, intervene in value grouping, influencing the pattern of the dependence relations obtained.

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