Morphometric evaluation of Kubaysa drainage basin using geographic information system

Abstract EN

The hydrological analysis of Kubaysa drainage basin has been studied using a Geographic Information System (GIS) program as a tool to understand the morphological systems and their interrelationships.

The study focuses mainly on the geometry, more emphasis being placed on the relationship between morphometric characteristics such as; stream order (Nu), stream length (Lu), drainage density (D), stream frequency (Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc) and form factor ratio (Rf), comprising the area properties and forming the base of analysis of the drainage basin.

A total number of 383 streams are identified of which 297 are 1st order, 66 are 2nd order, 15 are 3rd order, 4 are 4th order and one is of 5th order.

The drainage pattern of the stream network is mainly of dendritic type, which indicates the homogeneity in texture and possible lack of structural control.

The mean bifurcation ratio for the study area is 4.7 which falls within the standard range and shows that the basin conforms to the characteristics of a natural stream and indicating that the geological structures are less disturbing to the drainage pattern.

The drainage density (D) of the study area is 0.91 Km/Km².

This value indicates that for every 1.0 square kilometer of the basin, there is 0.9 kilometer of stream channel.

This makes the study area lie within the group of low density basins, which suggests indicates that the basin consists of moderately permeable rocks.

The elongation ratio (Re) is 0.48; the basin in the study area assumes a pear shaped characteristics indicating high degree of integration.

The circularity ratio is 0.43, which indicates that the basin is oval; tending towards elongation in shape with high level of integration.