Abstract:
Although Ethiopia has a large potential to develop irrigation, only 7.84% of the 3.7 million
hectares of land potentially available has been developed. To examine the underlying causes,
this study evaluates the suitability of surface water irrigation in Keto River catchment. The
study area covers an area of about 1058.592 square kilometers. This study was initiated with the
objective of analyzing the water and land resources potential of river catchments in this River
basin for irrigation development by using Geographic Information System. The hydrological,
meteorological, Digital elevation model, soil, Land use, land cover map data were gathered from
different organization of government and other concerned sectors. First elevation data of the study
area were delineated as 30m resolution, then, characteristics of flow direction, contours and
radius of elevation noticed. The potential irrigable land was identified by using slope, land
use/cover and soil in arc GIS software, spatial analysis tool to analyze their suitability
individually, then application of the weighted overlay tool was provided to condense overall
suitability factors as specific outcome, and suitability was conducted implementing FAO criteria
for surface irrigation. Analysis of the water resource potential of the study area was carried out
by using hydrological data after filling different gaps observed using techniques like the average
mean method and distance power method to screen them for further application. Here, there was,
flow duration curve developed, flood frequency tested, low flow analyzed to differentiate between
variability existed between time series of the records. The reservoir requirements of the catchment
were dealt with dependable flow by mass curve technique. Also crop water requirement of most
widely growing crops of the study area viz. Potato and Maize were computed from climatic data
as an input depending on the preference of agro climatic condition of the study area using
CROPWAT model, version 8. Potential irrigable land was identified out of the total catchment area
considering suitability outcomes for river catchments and selected crops agro ecology. The Gross
irrigation demand of selected crops for each month is computed for low flow analysis of 80%,
85%, 90%, 95%, and a 100% exceedence. The result suggests that the irrigation potential of the
area considering the analysis of possible low flows and crop gross irrigation requirement is
0.014ha.
