Abstract:
Soil is an essential resource for human livelihoods. Soil loss is one of the most important
environmental problems, and it remains as a major threat to soil fertility in Ethiopia. Soil
loss estimation is one of the prerequisites to install conservation and management of soil
and water resources. Watershed prioritization based on RUSLE model and morphometric
analysis has gained importance in soil and water conservation and management at
watershed level. This study was estimating the annual soil loss and prioritization
watershed using GIS, remote sensing, morphometric parameter and RUSLE model in
Dura watershed. Primary and secondary data for the study were collected from different
sources and used for the estimation of RUSLE model and morphometric parameters.
Here, RUSLE model and morphometric parameters analysis has been considered as
basic elements and applied to prioritization of sub watersheds. The estimated rainfall
erosivity, soil erodibility, slope length/steepness factor, crop management factor and
conservation practice factor range from 854.51 to 1048.55 MJ/ha.mm/h, 0.15 to 0.35
ton.ha.h/ha/MJ/mm, 0 to 13.63, 0.001 to 1 and 0.1 to 1 respectively. The result showed
that the annual soil loss from the watershed was in the range of 0 to 247.43ton/ha/year
with mean soil loss of 29.10ton/ha/year. The Dura watershed was found as 6
th stream
order. The mean bifurcation ratio was found as 2.7 for the watershed and it varied from
1.8 to 4.09 for the sub watersheds. The drainage texture of the sub watershed varied from
1.84 to 5.57. The drainage density of Dura watershed was found as 1.6 km/km2 while for
its sub watersheds ranged from 1.42 to 1.78 km/km2
. The Stream frequency values for the
sub watersheds vary from 1.79 to 2.6 while 2.23 per km for the watershed. The
elongation ratio of the watersheds varied from 0.62 to 0.67. The compound parameter
value of sub watersheds ranges from 3 to 5.1. Based on soil loss and morphometric
analysis, the sub watersheds have been classified into three categories as low, medium
and high in terms of priority for conservation planning. The analysis reveals that, out of
seven sub watersheds, SW2, and SW7 fall under high SW3, SW4 and SW6 fall under
medium and rest other fall under low category on the basis of morphometric analysis.
Similarly on the analysis of soil loss SW5, SW4, SW7 and SW2 fall under high SW3 and
SW6 fall under medium and SW1 fall under low category. This study recommended for
decision makers soil and water conservation measures should be planned for
implementation, starting from SW5 to SW1 based on the capacity of logistics, time, skill,
and budget availability.