PROBLEMS 15 



PROBLEMS 



lOL Find the discharge in a rectangular flume of new unplaned timber set on a 

 grade of 2 feet per thousand feet. The flume has a bottom width of 8 feet and the 

 depth of flow is 4 feet. 



102. The following data were obtained in a determination of the effect of algae 

 growth in a trapezoidal concrete-lined irrigation ditch. Bottom width 3 feet, side 

 slopes 1 on 1, width of water surface 6 feet, Q = 47 c.f.s. Elevation at Sta. 91 + 

 00, 875.13, at Sta. 98 + 73, 863.47. Compute the value of n. 



103. Uniform flow with a velocity of 6 feet per second is desired in a pyralin 

 flume to be used in a laboratory investigation. If the section is circular, 1 foot in 

 diameter, and is to flow half full, at what slope should it be constructed? What 

 allowance for adjustfnent should be provided, to cover uncertainty in the roughness, 

 if the length of the flume is 50 feet? 



104. An earth channel lined with shot concrete has side slopes of 1.5 vertical to 

 1.0 horizontal, tangent to a 3-foot radius at the bottom, and is laid on a slope of 

 0.004. What will be the depth of uniform flow for a discharge of 250 c.f.s.? 



105. What should be the bottom width of an earth canal with side slopes of 2 

 horizontal to 1 vertical and a uniform slope of 0.001, if it is to carry 2,000 c.f.s. at a 

 depth of 8 feet? 



