Assessment of the Performance of Gezira  Irrigation Scheme, Sudan
Creators: name: Jal Fnom Kojeaze Seach
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2010

description: The  objective  of  this  study  was  to  assess  the  performance  of  the  Gezira  Irrigation 
Scheme,  Sudan. To  assess  the  performance, water  supply  indicators  (Overall  consumed 
ratio,  relative water  supply,  relative  irrigation  supply, water delivery  capacity and water 
delivery performance);  cropping  intensity;  land productivity  indicators;  output  indicators 
(Output per cropped area, output per command area and output per unit irrigation supply) 
and  economical  indicators  (water productivity,  relative water  cost and  benefit cost ratio) 
have  been used.  For  this  purpose,  relevant  secondary  hydrological  data,  land and  crops 
data  and  information  for  the  period  from  1970/71  to  2008/09  were  collected  from 
Ministry  of Irrigation and Water Resources and  Sudan Gezira Board.  Ten-day  average 
meteorological  data  for  the  period  1971-2000  and  the  average monthly meteorological 
data  for  period  1989-2008  for  Wad  Medani  station  were  collected  from  Ministry  of 
Science and  Technology-Meteorological  Authority.  CROPWAT  8.0  software  was  used 
for  estimation  of  crop  water  requirement  and  irrigation  water  requirement  and  the 
performance  indicates methods were  employed to  determine  the  selected  indicators. The 
water  supply  indicators  such  as  seasonal  overall  consumed  ratio  during  the  seasons 1989/90-2008/09 ranged from  0.3 to  0.8, seasonal relative water supply values during the 
seasons  1970/71-2008/09  ranged  from  1.1  to  2.7 and  seasonal  relative  irrigation  supply 
during  the  seasons  1970/71-2008/09  ranged  from  0.8  to  2.0. These  results  indicate  that 
the  water  supply  vary  from  adequate  to  excessive  compare  to  estimated  demand.  The 
water deliver capacity during seasons  1970/71-2008/09 values varied between 0.7 and 2.4 
and  the  seasonal water  delivery performance  during  seasons  1999/2000-2008/09  ranged 
from  0.71  to  0.91showing that the water  is not a constraint in the  scheme  level but  issues 
of effective management. The  cropping  intensity during  season  1970/71-2008/09 ranged 
from  35% to  86%. The main crops  grown by  the  scheme are  sorghum, wheat,  groundnutland  productivity  obtained  from  farmer's  fields  is  due  to  many  factors  such  us  delay  of 
sowing  date  and  lack  of fund  for  operation  and  maintenance  and  excess  water  supply. 
During the  season  1995/96-2003/04,  the  output  per  cropped  area  of cotton  ranged  from 
205.5  US$  per  hectare  to  700.618  US$  per  hectare,  wheat  between  31.776  US$  per 
hectare  to  625.251  US$  per  hectare,  groundnuts  between  11.13  US$  per  hectare  and 
145.25 US$ per hectare and  sorghum between 21.85 US$ per hectare and 493.82 US$ per 
hectare.  The  output  per  command  area  ranged  from  per  51.3 US$  per  hectare  to  285.9 
US$ per hectare and the  output per unit  irrigation  supply ranged 7.7 US$/1000 m3 
to  37.9 
US$/1000 m3• 
The  water  productivity  for  sorghum  ranged  between  0.1  to  0.35  kg/m3, 
wheat  ranged  between  0.06  to  0.29  kg/m3, 
groundnuts  ranged  from  0.06  to  0.34  kg/m3 and  cotton ranged between 0.07 to  0.17 kg/m3. 
The water productivity was  low compared 
to  international  standard  which  is  ranged  between  0.20  to  2.5  kg/m3• 
The  low  level  of 
water  productivity  was  due  to  lack  of proper  water  management  and  hence  excessive 
water  losses and  low  inputs.  The  economical  indicators  used  were  Relative  water  cost 
(RWC) and Benefit cost ratio  (B/C). During the  seasons  1991/92-2006/07  the RWC value 
varied  from  0.03  to  0.07.  The  upper  limit  indicates  uneconomical  production.  The 
benefit-cost  ratio  during  the  seasons  1970/71-2008/09  ranged  between  0.01 and  2.0. The 
Gezira Scheme was moved  towards  the  lower  side  of the  range  indicate  no  improvement 
in  the  economical production due  to  low profitability.  Improving the  performance  of the 
scheme  can  be  attained  through  proper  planning  of  agricultural  seasons  by  adoption  of 
scientific methods  for  estimation  of crop water  requirement  such  as  F AO  methodology, 
insure  adequacy  of water  supply,  operation water  service,  increase  soil  fertility by  proper 
application  of  fertilizers  for  cotton  and  wheat  and  growing  of a  legume  crop,  establish 
sustainable  finance  policy  for  water  pricing  and  introduce  a  performance  assessment program for monitoring the  operation services.