Abstract:
Protection of upper catchment areas has importantly been becoming challenged since the forest
cover of upper catchment areas has been eroded dramatically for years. Especially, due to the
expansion of anthropogenic activities in the upper catchment areas in Sri Lanka, soil erosion, soil
degradation, and soil loss have come to the fore. This circumstance directly affects the natural
river systems. The key objective of this research was to analyze the drainage density and drainage
richness of the Kukule upper catchment and its micro catchments. For the methodological
approaches, this research considered the drainage density and the purification ratio, in addition to
the examining of river stream orders invented by A. N. Strahler (A. N. Strahler’s River
Network Classification Law). The cartographic applications, such as the topological significance
(e.g. elevations and water divides, etc.) and mapping of catchment areas have been prepared based
upon the Geographical Information System environment. According to the results, the Kukule
catchment was identified as a rich catchment in drainage density and purification ratio. The Kukule
catchment is identified as a fifth-order river basin that consists of higher numbers of stream
segments and nodes. This may be because a part of the catchment belongs to the Sinharaja tropical
evergreen forest reserve.
