Step 1: Recall relationships.
- (A) Mean velocity in Lacey regime channel $\propto S^{1/2} \Rightarrow$ I.
- (B) Mean velocity in lined channel $\propto S^{1/3} \Rightarrow$ II.
- (C) Normal scour depth in alluvial channel $\propto Q^{1/2} \Rightarrow$ III.
- (D) Wetted perimeter in Lacey's regime $\propto Q^{2/3} \Rightarrow$ IV.
Step 2: Match accordingly.
\[
A \to I, B \to II, C \to III, D \to IV
\]
Step 3: Conclusion.
Thus, the correct match is option (1).
Consider flow in a long and very wide rectangular open channel. Width of the channel can be considered as infinity compared to the depth of flow. Uniform flow depth is 1.0 m. The bed slope of the channel is 0.0001. The Manning roughness coefficient value is 0.02. Acceleration due to gravity, \( g \), can be taken as 9.81 m/s\(^2\).
The critical depth (in m) corresponding to the flow rate resulting from the above conditions is ________ (round off to one decimal place).
A hydraulic jump occurs in an open channel when the slope of the channel changes from ___________.