A 3.05 m wide, rectangular channel (n = 0.012) with a 0.0049 slope is able to move 13.6 m3/s of water. The channel narrows in order to create a critical flow. If the losses resulting from the steady reduction of width are disregarded, what width does the contracted section need to have in order to satisfy this condition?

Highway drainage is the process of extracting and regulating the excess surface water on the pavement by giving the desired slope. The construction of a highway drain helps to divert the water present on the surface, and sub-grade by the means of slope. …