Figure C10.5 shows a hydraulic model of a compound weir, one that combines two different shapes.
(a) Other than measurement, for which it might be poor, what could be the engineering reason for such a weir?
(b) For the prototype river, assume that both sections have sides at a 70° angle to the vertical, with the bottom section having a base width of 2 m and the upper section having a base width of 4.5 m, including the cut-out portion. The heights of lower and upper horizontal sections are 1 m and 2 m, respectively. Use engineering estimates and make a plot of upstream water depth versus Petaluma River flow rate in the range 0 to 4 m3 /s.
(c) For what river flow rate will the water overflow the top of the dam?
