With what Width will a rectangular channel be built to transport 13.5 m^3/sec of water to a depth of 1.8 m under a slope of 0.0004? use n=0.010? With what Width will a rectangular channel be built to transport 13.5 m^3/sec of water to a depth of 1.8 m under a slope of 0.0004? use n=0.010