IRRIGATION OPERATION MODELING APPROACH IN SURFACE IRRIGATION SYSTEMS

Irrigation system performance of Salihli Right Bank Irrigation Association was determined in this study and new water management model was proposed to improve irrigation performance of networks. To determine the water management efficiency of the Association, 6 secondary and 113 tertiary canals were investigated, water use efficiency, agricultural and environmental efficiencies were calculated. For water use efficiency, net water supply ratio was found to be 3.50 and total water supply ratio was found to be as 1.29 in Y2T37 tertiary. It was determined that net water supply ratio was higher than 2.5 and total water supply ratio was higher than 1 for all secondary canals. It indicates that excessive water was diverted to irrigation site and this negatively effected project irrigation efficiency (28,3%). Rate of irrigation was calculated to determine the agricultural efficiency. Irrigation ratio varied between 6.1 – 100 % for canals and realized as 94.3% for main canal. For environmental efficiency, it was determined that groundwater table of the site increased by 53 cm during the irrigation season and about 58.7% of irrigation water given to soil fed the groundwater. Irrigation water quality was found to be proper according to Ayers and Westcot irrigation water quality classification guides and water of main drainage canal was found to be non-problematic. In this study, it was concluded that both beneficiaries of surface irrigation system and water managers should adopt the recommended water management model to improve the system performance and to gain optimum benefit from the scarce resource.