EVALUATION OF SPRINKLER IRRIGATION SYSTEM AT BELES SUGAR DEVELOPMENT PROJECT
Creators: name: Fikadu Kinfe Abshiro
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2016

description: xii | P a g e
Irrigation is the largest  user of water. Effective and efficient use of water is very crucial to sustain water 
resources. Effective, sustainable, and efficient sprinkler irrigation system is a combined effect of proper 
system  design,  operation,  maintenance,  and  management.  Appling  appropriate  field  irrigation  practices 
safeguard that crops  could get peak supply of water in their root zone for achieving best yield of crops 
without facing water stress and damaging the quality of soils. Sugar  cane fields at study area  irrigated  to
irrespective  of  the  soil  type,  growing  month,  and  stage  of  crop  growth  with  the  design  application 
efficiency of 70%. But, now the system is not working with the full design capacity so that evaluating the 
actual sprinkler application efficiency under existing condition was very important. Therefore, this study 
was  conducted  to  evaluate  the  existing  actual  water  application  uniformity  with  design  standards,  and 
develop irrigation scheduling based on the actual existing water application with respect of soil, growing 
month and stage of growth. Primary and secondary data were used to attain the objective of the study. 
Representative soil samples were taken for soil texture, bulk density, field capacity and wilt point test. 
The  actual  water  application  uniformity  was  measured  for  single  and  four  overlapping  sprinklers  by 
installing catch can at a grid spacing of 3*3 m with two replications at hydrant pressure of 2.5 and 3.0 
bars.  Secondary  data  collected  were  weather  data,  effective  root  depth  and  crop  coefficient.  The 
performance parameters analyzed were, crop evapotranspiration, net irrigation requirement, net depth of 
application,  irrigation  interval,  sprinkler  set  hour,  uniformity  coefficient(CU)  ,distribution 
uniformity(DU),  and  system  uniformity,  and  application  efficiency.  The  average  actual  DU  and  CU 
obtained at 3 and 2.5 bars at existing sprinkler spacing of 18mx18m was 53% and 63% respectively. The 
value of CU was lower than the recommended value of 75%. The catch can data for single sprinkler were 
overlapped for different spacing‟s and values DU and CU were calculated. Acceptable value of CU equal 
to 75% and 76 % at operating pressure 2.5 bar and 3 bar respectively obtained at 12m x 18m spacing. The 
average sprinkler discharge at 3.0 and 2.5 bar operating pressure was 0.9 and 0.8 m
3
/hr respectively. The 
sprinklers had an average actual application efficiency of 62%. Sprinkler set hours obtained for the age of 
0-3, 3-6, 6-15 and &gt;15 month was 13, 19, 25 and 38 hr respectively. Irrigation interval obtained for age of 
0-3, 3-6, 6-15 and &gt;15 month varied with growing month and had a range of 7-10, 6-21, 7-20, and 16-24 
days  respectively.  According  to  the  study  the  system  was  not  working  under  full  design  capacity  and 
actual  application  uniformity  was  out  of  the  acceptable  range.  The  irrigation  scheduling  based  on  the 
actual efficiency was recommended with respect of growing month and stage of growth.