A rectangular concrete channel has a broad-crested weir at its downstream end as shown in Figure 5.16. The channel is 10 m wide, has a bed slope of 1 m/km and Manning’s n is estimated to be...

A rectangular concrete channel has a broad-crested weir at its downstream end as shown in Figure 5.16. The channel is 10 m wide, has a bed slope of 1 m/km and Manning’s n is estimated to be 0.012. If the discharge is 150 m^3/s,

(a) Calculate the minimum height of the weir (Δz) to produce critical flow

(b) If Δz = 0.5 m, calculate the upstream head (H₁) if C_d
= 0.88

 [(a) Δz = 0.179 m, (b) H₁
= 5.14 m]

Figure 5.16