<p>Ogee weir is an overflow structure, mainly used for flow diversion from rivers. After operation of an ogee weir on a river, the weir upstream face is usually subject to upstream sedimentation. To investigate the influences of sedimentation on hydraulic properties of ogee weir, a laboratory model of ogee weir with 0.30&#xa0;m height and 0.40&#xa0;m width was made for design discharge value of 0.040&#xa0;m³/s. The weir model was tested under movable upstream sedimentation by 3 different grain sizes of sediments. Using dimensional analysis, possible influencing dimensionless geometric and hydraulic parameters on upstream sedimentation pattern and discharge coefficient of ogee weir were determined and their influences were quantified by using experimental data and field observations. Results indicated that under equilibrium condition of depth and longitudinal slope of upstream sedimentation, Shields parameter of accumulated sediments behind ogee weir was stabilizing at its critical value. At design discharge and upstream sedimentation by coarse sediments, it resulted in weir water head reduction by 26.2%, energy rising of approach flow by10.2%, and in the following, developing of a flow separation zone with sub-atmospheric pressure on weir downstream surface. Furthermore, it resulted in decrease in discharge coefficient of ogee weir by 13.6%. Due to energy rising of approach flow, the sequent depth and length of downstream hydraulic jump of weir were also exceeding from their corresponding values at no-sedimentation condition. In the prototype scale, it resulted in exiting the hydraulic jump from stilling basin, intense scouring below stilling basin, and finally damage to weir structure facilities.</p>