A triangular canal of most efficient proportion has a depth of 3 m. What is the hydraulic radius of this canal?

A canal transports a flow of 100 m3/s with a depth of 1.5m. This canal is made of concrete (Manning coefficient of 0.012) and has a slope of 0.02%. The cross-section can be found below. www.www 1.5 m B Figure 1 Canal cross-section Q a) Determine the width of the canal (B) if the flow is currently at normal depth. b) A crack in the concrete was recently discovered. Drying up that portion of the canal with the help of a cofferdam has been suggested in order to correct the situation. It has been suggested that this structure be 50% of the width of the canal. What are your thoughts on this? Is this feasible? What are the consequences? You must clearly state your opinion and explain clearly the effects the cofferdam will have on the flow of water in the canal if it is set up as suggested. Take L=0.5*B, where B is your answer found in a) 2.5 m L B Figure 2 Aerial view of canal with cofferdam (dotted line)

A rectangular channel is 4.0 m wide and 7.0 m deep, but it is filled with water up to only 6.0 m from the bottom. The channel walls are made of corrugated metal. Calculate the hydraulic diameter.