Hydraulic Cross-section
1. Determine the discharge of a new planed timber flume of rectangular cross section 1.2 m
wide, flowing 0.6m deep, with a fall 2.5m per 1000m. n=0.012
2. What should be the slope of a planed-timber flume, rectangular in cross section to carry
3.25
if the width is 1.8m and the depth of flow is 1.2m? n=0.012
3. A rectangular concrete lined canal is to carry 1.35
. The bottom width is to be twice the
depth. What should be the dimensions of the stream cross section if the slope is to be 0.001?
n=0.012
4. A conduit is to have a cross-sectional area of 0.9 . Compute the wetted perimeter and the
hydraulic radius if the section is semicircular open channel.
5. What should be the slope of a semicircular smooth steel flume with smooth joints to carry
2.7
, the diameter of the flume being 2.4m? n=0.012.
6. A smooth metal flume of semicircular cross section has a diameter of 1.8m and a slope of
0.005. What diameter of corrugated metal flume will be required to have the same capacity?
n=0.025 for corrugated metal flume.
7. An open sewer is to be of most efficient cross section and lined with brick, well laid on a
grade of 3m per 5km. The flow capacity is to be 27
. Determine the proper cross section.
n=0.013.
8. Determine the bottom width of an earth canal in good condition, having side slopes of 2
horizontal to 1 vertical, if it is to have the most efficient section and carry 5.4
with a grade
of 2m per 5km.
9. What should be the bottom width and the depth of flow for a canal of most efficient
trapezoidal section, side slopes of 2 horizontal to 1 vertical, to carry 5.4
with a velocity of
0.75m/s? What should be the slope of the canal if it is to be in earth and kept in good
condition?
10. In order to provide water from a nearby spring, a triangular flume of efficient section was
provided on a slope of 0.21%. Assuming the roughness of coefficient of the channel to be
n=0.018. Obtain the depth of flow in meters, of the water in the flume if it is discharging at the
rate of 2
.