Figure 7.30 shows a wide rectangular channel with two segments. Both segments are very long. The…

Figure 7.30 shows a wide rectangular channel with two
segments. Both segments are very long. The Manning roughness coefficient of
segment I is n = 0.025. The roughness coefficient of segment II is n = 0.020.
The first segment (segment I) comprises an outlet of a reservoir and its slope
is S0 = 1.7  10-3. The slope
of segment II is S0 = 0.025. Segment II ends at an overfall.
However, right before the overfall the bottom of the channel is elevated by an
amount Z. The water depth above that
elevation is yF = 0.95 m. Upstream of that elevation, the water
depth is yE = 2.50 m. The free
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Figure 7.30 shows a wide rectangular channel with two
segments. Both segments are very long. The Manning roughness coefficient of
segment I is n = 0.025. The roughness coefficient of segment II is n = 0.020.
The first segment (segment I) comprises an outlet of a reservoir and its slope
is S0 = 1.7  10-3. The slope
of segment II is S0 = 0.025. Segment II ends at an overfall.
However, right before the overfall the bottom of the channel is elevated by an
amount Z. The water depth above that
elevation is yF = 0.95 m. Upstream of that elevation, the water
depth is yE = 2.50 m. The free surface of the reservoir water above
the bottom of the channel entrance is H.

(a) What is the discharge per unit width of the channel?

(b) What are the normal depths of segments I and II?

(c) What are the water depths at points A and B, and what
are the values of Z and H?

(d) How many hydraulic jumps are in the channel? Where are
they and why do they occur?

(e) What are the water depths upstream and downstream of the
hydraulic jumps? What is the head loss of the hydraulic jump?

(f) What types of channel segments and hydraulic profiles
are present at each of the channel segments?

(g) Provide a schematic sketch of the channel with the
critical and normal depths labeled, as well as the hydraulic profiles and
hydraulic jumps along the channel.

(h) Using spreadsheets, calculate the hydraulic profiles.
Apply appropriate vertical and longitudinal geometrical scales, and provide a graphical
description of each hydraulic profile.

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