Abstract

Water  induced  soil  erosion  has  been  continued  to  threaten  the  land  resources  in  sub  humid  northwestern  highlands  of  Ethiopia.  Human-induced  land  cover  (LC)  changes due  to  improper  land  management  practices  are  contributing  factors  in  deteriorating  soil  quality. Soil and water conservation measures have been implemented without site-specific scientifically quantified soil erosion data and priority bases in this regard; this study was conducted with a view to quantifying soil erosion in Anka-Shashara watershed. To do this, we have opted to use the RUSLE model based on geographic information systems. By collecting data on rainfall, soils, vegetation, slopes and conservation practices separately as a layer and determining the pixel values for each of these factors, a quantified assessment of  erosion  in  the  basin  is  obtained.  The  result  reveals  that  the  mean  annual  soil  loss  (15.22t/ha/yr) of the most parts of study area falls in tolerable levels and almost 66% (1594 ha), moderate level about 23% and 10% at high level of watershed. The soil loss of watershed is classified in to four main classes. None to Slight rates of soil erosion (0-10t/ha) is cover the almost 66% of watershed moderate about 23% and high about 10% of erosion  rate  as  seen  from  the  erosion  rate  distribution  map.  The  upstream  of  catchment  needs management and protection of those existing resources and the fundamental attention for SWC as recommended bases. Therefore, to reduce sedimentation problem and  ensue  sustainability  of  the  watershed  need  to  special  attention  for  implementing  recommended  SWC intervention at the earlier.

Keywords

GIS, RUSLE, soil loss, Anka-shashara