In many branch of engineering, it has been important problem to understand quantitatively flows in curved pipe, or along curved surface from the practical point of view. in particular, pressure losse dates are available for the analysis and design of internal flow system. for example, in dam conduit, the flow is generally three-dimensional and theoretical treatment is considerably complicated. In this paper, imcompressible potential flow in curved pipe of comparatively small curvature is treated considering the influence of centrifugal force and deduced practical simple equation. Similar treatment is given for the flow over flood chute of dam. Pressure loses and flow velocity in conduit flow have been measured in model experiment, the measured is considered, from the practical point of view, to be in good agreement with the calculated.