Question

Consider the following statements which relate to different types of water surface profiles. Curve types conform to usual classifications$y_{c}and{y}_0$ (critical and normal depths):
1. Type-3 curves lie between $y_{c}and{y}_0$
2. All curves where $y_c<y_0$ are unaffected by upstream disturbances.
3. All curves where $y_c>y_0$are influenced by downstream disturbances.
4. All curves approaching the 'y' line approach it asymptotically except for the C curve where $y_c=y_0$

Which of these statements are correct?

• A. 1, 2, 3 and 4
• B. 1 and 2
• C. 1 , 3 and 4
• D. 2, 3 and 4

Answer 1

The correct option is D 2, 3 and 4

(c)
For $y_c<y_0$ the curves are $M_1,M_{2}and{M}_3$. The control section for mild profiles is downstream so upstream disturbance does not affect them.
Similarly for $y_c>y_0$ the curve are $S_1,S_{2}and{S}_3$. The control section for sleep profiles is upstream and downstream distubance does not affect them.

Type-2 curve lie between $y_{c}and{y}_0$.
Type-3 curves are above $y_{c}or{y}_0$ whichever is large.
Type-1 curves are below $y_{c}or{y}_0$ whichever is smaller.