Question

Calculate the length of the downstream floor for a vertical drop weir having crest shutters, if the total maximum head loss is 2.5 m. Assume the value of Bligh’s constant as 12.

(a) 11.62 m

(b) 11.80 m

(c) 12 m

(d) 10 m

I had been asked this question in a dream while sleeping

The origin of the question is Seepage Theories topic in division Seepage Theories and Weirs and Barrages Design of Irrigation Engineering

Answer 1

The correct option is (a) 11.62 m

Easy explanation: Total max. head loss (HL) = 2.5 m and C = 12

As per Bligh, the length of D/s floor with crest shutters is given by –

L2 = 2.21 C (HL/13)^1/2 = 11.62 m.