Abstract:
Irrigation is an important investment for improving rural income through increased
agricultural production. The development of irrigation and agricultural water management
holds significant potential to enhance productivity and reduce vulnerability to the clim actic
volatility in any country. The major consequence of irrigation development are fluctuations
of basic climatic elements such as rainfall, temperature, humidity , and other atmospheric
conditions. This study was concerned with assessment of surface irrigation potential in the
Temicha watershed by implementing Arc GIS 10.1. The study identifies suitable land, crop
water demand and supply for dominant crops grown in the catchment, and also providing
suitability maps for surface irrigation development. To identify suitable land the land
suitability parameters were used such as land slope, soil type and land cove r land uses.
The suitability of each parameters analyze individually and then application of the
weighted overlay tool was provided to get the overall suitability factors and suitability was
conducted by considering FAO criteria for surface irrigation deve lopment. The crop water
requirement of major growing crops of the study area were identified based on some earlier
studies and agro climatic condition of the study area i.e. Wheat and Maize and its demand
of water was estimated by implementing CROPWAT-8 model as an input of climatic data’s.
The stream flow data in the watershed were assessed by implementing the SWAT model
with an interface Arc GIS 10.1 software. The model was calibrated and validated from
observed stream flow of the watershed. The calibration and validation result showed that
model performance evaluation statistics coefficient of determination (R
2
), Nash-Sutcliffe
model efficiency (ENS) and Relative Volume Error (RVE) were in the acceptable range (R
2
> 0.8, ENS > 0.8 and RVE < -10 % ). This shows that a good agreement between the
simulated and observed values. The result of the weight overlay analysis revealed that
45.5% (49629.2 ha) of lands in the watershed were in the range of highly sui table for
marginally suitable class due to the combined effect of slope, soil and land use land cover
suitability and 54.5% (59445.9 ha) of the area were unsuitable for surface irrigation. So
that, the current study considered only slope, land use land cov er and soil physical
properties but other suitability factors like, socioeconomic, environmental issues, soil
chemical properties, method of irrigation system and other relevant parameters should be
studied for detail assessment of irrigation development in the study area
