Theoretical and actual performance relating the engineering ef­fective factors to water flow rates and distribution uniformity for gated pipe system were studied. The results and discussion of the study in­cluded the following aspects of the gated pipes performance: (1) Theo­retical performance of circular opening of the gate, (2) Actual perfor­mance of circular opening (orifice) of the gate, and (3) Obtained different discharge rates of the gate. The results showed that, in general, theoretical model is reliable and can be utilized to predict and compute the hydraulic coefficients of gated pipe system. The water flow rates which have been derived theo­retically and actually are applicable to different surface irrigation sys­tems. The gate discharge ranged from 0.1 to 6.01/sec which were uti­lized to irrigate long furrows and long strips with length ranged from 100 m to 180 m.