Abstract:
Any modest improvement in the performance of irrigation water management for thirsty
sugarcane schemes management has substantial impact. One way this can be achieved is
through a systematic evaluation of the performance of existing schemes in order to take
action towards improving the technical, environmental and economic health of the system.
This is specifically true with the introduction of new water conveyance system such as hydro flume. This study was initiated to investigate performance of Metahara Sugar Estate
irrigation system in terms of hydraulic and economic performance indicators. The
performance indicators used to evaluate the irrigation schemes are oriented towards the
variables that directly or indirectly affect water deliveries and water spreading effects. The
evaluation was made using seven technical performance indices such as conveyance
efficiency, application efficiency, water storage efficiency, water distribution uniformity,
deep percolation fraction, runoff ratio, sustainability, sugarcane performance as a function
of water application and cost-benefit comparison of open earthen ditch (feeder ditch) with
hydro-flume. Crop water requirement based on soil classification and irrigation scheduling
of the scheme were also assessed. The technical evaluation was done using three irrigation
events on three representative plantations’ fields (from the head, middle and tail end of the
command area); whereas the performance of sugarcane as a function of flow rate and cost
benefit analyses of hydro- flume was evaluated using sample cane from different variety from
different field evaluation was done by laboratory, secondary data was collected from
stakeholder. The results indicated that the mean values of discharge were 2.88, 3.45 and 3.45
l/s respectively which is less than the designed discharge of 5 l/s. The field assessment shows
that performance of the irrigation scheme is unsatisfactory in terms of conveyance efficiency,
application efficiency, deep percolation fraction, run-off ratio and sustainability with mean
values of 92.17%, 58.55%, 22.92%, 18.58% and 93%, respectively. However, the
distribution uniformity, and water storage efficiency were satisfactory with mean values of
85.42%, and 99.43. The range of cane and sugar yield found in the study was from 9.08 to
13.12 t/ha/month, respectively. Total net cost saving and revenue obtained by implementation
of hydro-flume were 1,947,883.64 birr, respectively. As a result, weak operation of irrigation
water, poor irrigation water management and poor maintenance of the scheme is seen and
its sustainability is uncertain.
