Abstract:
The main objective of this research is to evaluate land suitability for surface
irrigation method based upon a parametric evaluation system in an area of
33,383.09 ha in the Kobo Valley, Eastern Amhara. Key factors that significantly
affect irrigation suitability evaluated in this study include physical land features
(land use, soil, and slope). These factors were analyzed and evaluated based on
rating table values, then reclassified and overlaid to identify suitability maps for
surface irrigation methods using Geographic Information System (GIS).
Groundwater and climate (rainfall and evapotranspiration) data were used to
estimate the groundwater potential, which indicates the corresponding irrigation
potential for major crop. The obtained results showed that 77.7 % (25,934.08 ha) of
study area was highly suitable (S1), 15.5 % (5,176.84 ha) of the study area was
moderately suitable (S2), 6.1 % (2,033.75 ha) of the study area was marginally
suitable (S3), 0.4 % (124.32 ha) of the study area was currently not suitable (N1) and
0.3% (114.11ha) of the study area was permanently not suitable (N2) for surface
irrigation purpose. In this particular study drainage was the major limiting factor
and the cause for the area to be moderately suitable (S2); drainage and texture were
the major limiting factor and the cause for the area to be marginally suitable (S3).
Irrigation well yield potential using ground water assessment result showed that a
yield can satisfy the crop water need of the study area two times beyond net
irrigation requirement, indicating that Kobo valley has high amount of ground water
resource to fulfill maximum crop water need in the area using surface irrigation
method. Hence, the majority of the study area was highly suitable and potential in
terms of surface irrigation and ground water resource.
