<![CDATA[Control-gate operation affects discharge and water-conveyance performance in secondary irrigation canals. This study evaluates the hydraulic performance of the Boki 2-Boki 3 Secondary Canal in Pinrang Regency under five gate-opening levels and identifies a relative optimum opening based on discharge capacity, conveyance efficiency, and water loss. A quantitative field-survey approach was applied at six observation stations (STA 0+000, 0+200, 0+700, 1+200, 1+460, and 1+468) using gate openings of 15, 30, 45, 65, and 85 cm. Surface-flow velocity was measured using the float method and calculated from V=L/t; the measured surface velocity was used directly without a correction factor to determine discharge from Q=A×V. Conveyance efficiency and water loss were evaluated from upstream and downstream discharge. The results show that larger gate openings increased flow area, velocity, and discharge, but were accompanied by greater water loss and lower total conveyance efficiency. The 15 cm opening produced the highest efficiency of 85.89% with a water loss of 0.0316 m³/s, whereas the 85 cm opening produced the largest upstream discharge of 1.4638 m³/s but reduced efficiency to 71.97% with a water loss of 0.4103 m³/s. The 45 cm opening was identified as the relative optimum among the tested conditions, providing an upstream discharge of 0.5618 m³/s, an efficiency of 82.79%, and a water loss of 0.0967 m³/s (17.21%).]]>
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