Zredukowane współrzędne obrysu strumienia na trapezowym progu przepuszczalnym z przelewem o ostrej krawędzi na skarpie górnej

The purpose of the work was to develop a typical shape of water surface profi le above trapezoidal gabion sill with the sharpcrested weir on the upstream slope. Reduced co-ordinates of the water surface profile above trapezoidal gabion sill with a sharp-crested weir on the upstream slope were developed. The ordinate points of the contour were reduced in relation to the height of the upstream water level above the sharp-crested weir. The cut off points of the contour were reduced according to the length of the zone influencing the stream to the inside of the stone sill. In the analyzes, the results of laboratory tests were used, according to which the shape of the free surface profile reduced coordinates was developed. The analyzed sill consisted of the permeable part filled natural aggregates and the solid part in the form of an inclined sharp-crested weir. The sill had a symetrical trapezoidal shape with the slopes of 1 : 1. The shape of the stream flowing over the analyzed sill depends on the head of the upstream water level above the crest of the slope weir. As a result of the conducted analyzes, a uniform stream shape was obtained for both the free and wave flow of the disturbance zone. The profiles obtained have strong correlation dependence. The obtained results can be taken into account during design similar hydraulic structures.