A sharp-crested suppressed rectangular weir is to be used to regulate the depth of water in a navigation project. The depth in the channel must be maintained at least 10 m in order for vessels to...

A sharp-crested suppressed rectangular weir is to be used to regulate the depth of water in a navigation project. The depth in the channel must be maintained at least 10 m in order for vessels to navigate the channel. The channel slope is essentially horizontal, its width is 6 m, and its invert is at elevation 10 m above sea level. The design low flow discharge is 1.5
/s for a recurrence interval of 20 years.

a. What is the exceedance probability of the design?

b. What is the probability that vessels will not be able to navigate the channel at least once in the next 10 years?

c. What must be the elevation of the weir crest in order to meet the design specifications? Assume the discharge coefficient is 0.61.