An assessment of the Mush Irrigation Scheme (MIS) in Debre Birhan, Amhara, Ethiopia was
conducted during the spring1
(Tseday) season of 2015. The study aimed to evaluate the
operation and efficiency of the irrigation scheme and assess potential cropping and water
management alternatives for potato, fodder and other cultivated crops. The evaluation made
use of group discussions, farmer surveys and field measurements. This assessment underlies
the approach of the Africa RISING Project to facilitate sustainable intensification of agricultural
production using a systems (in this case scheme) approach. It evaluated the option of irrigating
alternative crops and its potential effect on both crop and water productivity as well as
potential irrigation expansion.
The operation of the system is constrained by water resource availability and capacity to
utilize the limited water resources efficiently. Springs supply the scheme with a discharge of
0.16 m³/s. As the nursery uses roughly 40 % of the available flow during weekdays only 0.09
m³/s is available at the head of the canal for irrigation. As such, the scheme management faces
challenges to provide water access to the members of the three groups in an equitable
manner. Members currently irrigate an average of 0.34 ha per farmer. Due to the dilapidated
state of the canal and leakages from poorly maintained outtakes, transmission losses between
0.25 and 0.67m3
/hr/m occur. The system, though operating at acceptable system efficiency,
has highly variable application efficiencies between different farmers and crops, ranging
between 21 and 80%, which partly explained the large variability in land and water
productivity observed in the scheme. In spring season (Tseday) land and water productivity
were found lowest for lentil (527 kg/ha and 0.51 kg/m3
, respectively) while higher values were
obtained for potato (6800 kg/ha and 6.54 kg/m³, respectively). While the water productivity is
higher, for potato the crop has a higher water demand throughout the season stressing the
scheme further. Through efficient management of flood irrigation (70%), the current irrigated
acreage of 27 ha could be increased to 45 ha (of potatoes) or 63 ha of irrigated lentil. Improved
irrigation methods and/or on-farm water management may lead to even larger increases in
irrigable land.