Question

Criteria for selection of site for construction of embankment type of water harvesting structures are:
(A) The site should be 0.5 km away from settlement area.
(B) The permeability of the soils in storage area should be minimum in percolation tank.
(C) The command area should be as close as possible to the dam/pond site.
(D) The downstream area should permit natural passage for safe disposal of surplus water.
Choose the correct answer from the options given below :

• A. (A), and (C) only.
• B. (B), (C) and (D) only.
• C. (A), (C) and (D) only.
• D. (B) and (D) only.

Hint:

Remember that a percolation tank's primary purpose is to let water seep down to recharge the aquifer. Therefore, soil in its bed must be highly permeable. Since statement (B) is false, eliminating any option with (B) leaves you with the correct answer.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Site selection for embankment-type water harvesting structures (such as farm ponds or check dams) involves evaluating safety, economic viability, and engineering feasibility.
Detailed Explanation:
Let us analyze each of the given criteria:
- (A) Distance from settlement area: To prevent safety hazards, structural flooding, and vector-borne diseases, water harvesting structures are ideally placed at a safe distance (e.g., $0.5\text{ km}$) away from the main settlement area. Thus, (A) is a valid criterion.
- (B) Permeability in percolation tank: This statement is incorrect. A percolation tank is designed to recharge groundwater, so the soil in its storage area should have high permeability, not minimum. Thus, (B) is false.
- (C) Proximity of command area: The command area (the fields to be irrigated) should be as close as possible to the storage site to minimize conveyance water losses and pipeline costs. Thus, (C) is a valid criterion.
- (D) Downstream safe disposal: There must be a natural, safe downstream passage (spillway) to release surplus water during heavy storms without causing structural damage to the embankment. Thus, (D) is a valid criterion.
Thus, the correct criteria are (A), (C), and (D).

Step 2: Final Answer:
The correct combination matches Option (C).