[amp_mcq option1=”Depends upon the $$\frac{{\text{b}}}{{\text{d}}}$$ ratio” option2=”Is independent of the $$\frac{{\text{b}}}{{\text{d}}}$$ ratio” option3=”Is independent of the depths of $$\frac{{\text{b}}}{{\text{s}}}$$ cut off walls” option4=”None of these” correct=”option1″]
The correct answer is: A. Depends upon the $\frac{{\text{b}}}{{\text{d}}}$ ratio.
The exit gradient of surface flow is the ratio of the hydraulic head at the exit to the hydraulic head at the entrance. It is a measure of the energy loss that occurs as the water flows through the channel. The exit gradient is affected by a number of factors, including the channel geometry, the flow rate, and the roughness of the channel bed.
The $\frac{{\text{b}}}{{\text{d}}}$ ratio is the ratio of the width of the channel to the depth of the water. This ratio is important because it affects the hydraulic radius of the channel. The hydraulic radius is a measure of the cross-sectional area of the channel divided by the wetted perimeter. The hydraulic radius is a key factor in determining the flow rate in a channel.
The exit gradient is inversely proportional to the hydraulic radius. This means that as the hydraulic radius increases, the exit gradient decreases. The hydraulic radius is affected by the $\frac{{\text{b}}}{{\text{d}}}$ ratio. As the $\frac{{\text{b}}}{{\text{d}}}$ ratio increases, the hydraulic radius decreases. This means that the exit gradient increases as the $\frac{{\text{b}}}{{\text{d}}}$ ratio increases.
Therefore, the exit gradient of surface flow depends upon the $\frac{{\text{b}}}{{\text{d}}}$ ratio.