Establishing the average mean slope of the whole network of stream segments in drainage basins (case-study: Barlad basin - Romania)

摘要

Studying the average mean slope of the whole network of stream segments in a given drainage basin is a useful undertaking for getting an insight into the hydrological and geomorphological dynamics and evolution of drainage basins. Determining this variable means starting from Horton-Strahler's Classification system of stream segments by order of magnitude, each segment being GIS-inventoried, assigned the order of magnitude, length and falls of extreme points. Once these values are measured, the drainage model defined by the law of successively higher-orders of the number of stream segments, summed lengths and calculated average lengths can be worked out. The same methodology was used in establishing the morphometric model of falls given by the law of the number of segments and the laws of summed and average falls. The ratios between the value series defining the law of falls and of total lengths yield the law of average mean slopes of successively higher-order of stream segments. The data obtained enable calculating the average mean slope of stream segments which, correlated with the mean slope of the basin area, proves that close dependency relationships between the two elements do exist in terms of the geographical factors as a whole.