A sharp-crested weir is constructed across a wide rectangular channel that carries a specific discharge of 6.5  /s as shown in Figure P15.34. The channel has a bed slope of 20 cm/km and a Manning...

A sharp-crested weir is constructed across a wide rectangular channel that carries a specific discharge of 6.5
 /s as shown in Figure P15.34. The channel has a bed slope of 20 cm/km and a Manning roughness coefficient of 0.026. The weir has a sill height of 3.0 m and the discharge per unit width over the weir 1s given as

where
 = 0.7 is the discharge coefficient and
 is the water head over the weir. Determine the normal and critical depths. Estimate the distance upstream of the weir where the depth of flow is 4.75 m.