A broad-crested weir is located in a 40-m-wide rectangular channel, as shown in Figure P15.23. The channel conveys a discharge of 500  /s under a bed slope of 1.8 X  .The Manning roughness...

A broad-crested weir is located in a 40-m-wide rectangular channel, as shown in Figure P15.23. The channel conveys a discharge of 500
 /s under a bed slope of 1.8 X
 .The Manning roughness coefficient, n, is 0.032. The sill height of the weir is 2.0 m. The weir discharge is given as

 where Bis the weir width,
 is the discharge coefficient = 0.86, and h is the water head above the weir. Determine the length of the backwater curve using the step-by-step method.