EVALUATION OF STREAM FLOW UNDER LAND USE LAND COVER CHANGE  AND ASSESSMENT OF SUITABLE LAND RESOURCES FOR SURFACE  IRRIGATION; CHEMOGA CATCHMENT, ABAY BASIN, ETHIOPIA
Creators: name: ANMUT ENAWGAW
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2017

description: To stay alive in earth surface, land and water are indispensible. To enhance the agricultural 
productivity  and  socioeconomic  development  in  agricultural  catchment,  irrigation 
development is an important issue. The initiation of  this study was to evaluated  stream flow 
under  land  use  land  cover  change  and  assessment  of  suitable  land  resources  for  surface 
irrigation.  The  methods  used  include  desk  study  of  the  previous  studies  related  to  present 
study. Data were collected from  MOWIE,  MOA,  ENMA and other related institutions. After 
collecting the necessary data, filling of missed data and quality checking was made.  The land 
use land cover classification was performed using ERDAS imagine 2014 which was used for 
further analysis of GIS  and SWAT.  To estimate  surface water of the  catchment  was  using
SWAT model after calibration and validation. CROPWAT 8 was used to determine the water 
requirement of the dominant crops  grown in the catchment.  Surface water availability  was 
assessed  in  sub-watersheds  of  river  catchments.  In  Chemoga  catchment  various  factors 
effects  resource  bases  like  expansion  of  residential  area,  deforestation  and  increase  of 
agricultural  land  and  this  depict  that  change  of  land  use  land  cover  in  the  catchment.  The 
selected land use land  cover  years of 1994 and  2013 were used  for evaluation of land use 
land cover change impact on seasonal stream flow and to the major components of stream 
flow  as well as the current land use land cover map was used  as a factor  for land suitability 
evaluation. Due to the land use land cover change the catchment hydrology was affected. The 
result depicts that in wet season  (surface runoff)  the stream flow increase  due to this rugged 
land  surface  occur  so  hinder  the  sustainability  surface  irrigation  and  in  dry  season  (lateral 
flow &amp; ground water flow)  the stream flow decreases  so  connate water stress to the  irrigated 
crops.  So watershed management approach should be done in the catchment.  The coefficient 
of determination (R
2
),  nash-sutcliff efficiency (ENS), and relative volume error (RVE) were 
used for evaluating the  model performance.  The flows in the catchment are able to satisfy 
gross  irrigation  water  requirements  of  one  variate  crops  in  each  catchment  to  the  irrigable 
areas  but  to  satisfy  irrigation  demand  to  the  whole  crop,  with  the  help  of  semi-detailed  to 
detailed design document analysis construct water harvesting structures.  The land suitability 
was evaluated using factors such as slope, land use land cover, and soil physical properties 
(soil depth, soil texture and soil drainage) and finally overall suitability map of the catchment 
was  produced  using  weighted  overlay  analysis  tool  on  Arc  GIS.  In  the  weighted  overlay 
analysis; high weightage was given for slope, since it  is the high determinant factor in the 
evaluation  of  the  given  area.  Other  suitability  factors  like  socioeconomic,  environmental 
issues,  and  soil chemical properties should be studied for sustainable irrigation development 
in catchment.