Abstract:
Watershed prioritization has gained importance in natural resources management, especially in the
context of watershed management. RUSEL model and Morphometric analysis has been commonly applied to prioritization of micro watersheds. In the present study, prioritization on the basis of RUSEL
model and morphometric analysis of watersheds has been performed for the Upper Bilate watershed.
Eighteen micro-watersheds were delineated and designated as MWSD-1 to MWSD-18 for prioritization
purposes. A particular micro-watershed may get top priority due to various reasons but often, the severity of land degradation is taken as the basis. A methodology, based on RUSLE and Morphometric
analysis, has been applied using remotely sensed data, ASTER DEM together with other ancillary data
in a ArcGIS10.3 environment. The analysis shows that RUSLE model and Morphometric analysis helps
to categorize micro-watersheds into different levels of erosion risk and identify areas that require priority to conservation measures in relative to others. In both RUSEL model and morphometric analysis,
and the resultant ranks, the micro-watersheds have been classified into five categories in relation to
their priority for soil conservation measures: very high, high, moderate, low and very low. Based on
the RUSLE model, the potential average annual soil loss of each micro-watershed in the watersheds
ranges from 0.15-2985 t/ha/year with a mean annual soil loss of 16.08t/ha/year. The result showed that
Micro-watersheds (MWSD-3, 6, 8 and 16) estimated very high soil loss (16.03-44.17t/ha/year) and fell
under high soil erosion classes. About 21.03% of the micro-watersheds fall in below the annual average soil loss of the entire watershed. Based on Morphometric analysis, different prioritization ranks
were ascribed following the computation of compound factors. It is found that micro-watersheds
(MWSD-8 and 6) and micro-watersheds (MWSD- 10) are categorized in the class of very high and very
low priority respectively and about 38.47% of micro-watersheds are classified in the categories of very
high and high priority. With reference to the integration of the two methods of prioritization, microwatersheds (MWSD-3, 6, 8 and 16), and (MWSD- 5, and 11) can be classified in the class of very high
and high priority class respectively. By contrast, micro-watersheds (MWSD- 13, 17 and 18) and microwatersheds (MWSD- 10) are categorized in the class of low and very low priority respectively. About
40.22% of the watershed falls in the categories of very high and high priority. As a result the critical
micro-watersheds which are under very high and high category were selected and prioritized to be intervened for conservation and other rehabilitation measures.
