| Abstract | Irrigation system performance should be evaluated in order to determine the efficiency of the irrigation projects and to develop guidelines for performance improvement. In this study, the irrigation system performance of three irrigation projects located in the different regions of Thailand was assessed. The selected projects which are under the Royal Irrigation Department (RID) of Thailand include Mae Tang Project, Pranburi Project and Dom Noi Project. Three groups of performance indicators and a single indicator suggested by IWMI were selected in this study. They included Service Delivery Performance (SDP), Financial Performance (FP), Productive Efficiency Performance (PEP) and Environmental indicators. The relevant data associated with these indicators were taken from RID data base covering the period from 2003-2007 and was used for calculating the irrigation system performance. Based on the performance indicators, a comparison among the three projects was done. The evaluation results showed that Pranburi Project has the highest performance among the three projects. The average Relative Water Supply (RWS) for wet and dry seasons during the four year period were 2.61, and 1.54 respectively. Relative Irrigation Supply (RIS) on the other hand, were 2.96 and 1.13 for wet and dry, respectively. However, the Management, Operation and Maintenance (MOM) value was 55.15 $US which was considered unsatisfactory since it is lower than the target value of 58.6$US. PEP was also highest in Pranburi where average Output per unit serviced area, Output per unit irrigated area, Output per unit irrigation supply and Output per unit water consumed were 1,973.78 $US/ha, 2,111.25 $US/ha, 0.1850 $US/m³ and 0.2580 $US/m³, respectively. In the case of Mae Tang Project, a moderate level of performance was obtained considering that RIS (dry) for year 2004 and 2005 are 0.97 and 0.95 respectively which is below the threshold value of 1- for this indicator. However the MOM value (63.76$US) was found satisfactory. Also PEP was found to be at moderate level since output indicators are lower than Pranburi. For Dom Noi Project it was found to have the lowest performance based on the low values obtained for all the above indicators. To improve SDP, better water management is required to control losses and save water to meet agricultural demand and to expand cultivation areas if necessary. For improving FP the manager of the project should raise this problem to RID to get more budgets for improvement. In addition, to improve PEP the introduction of high value crops would be another alternative solution for improving productivity. However, climate, soil properties suitability and the experience of farmers should be taken into account. Strong farmers' participation, cooperation and correspondence are also necessary for irrigation project to achieve its goal of improving system performance. |