Question

Tetrasodium polyphosphate is used in ponds to reduce

• A. Evaporation
• B. Seepage loss
• C. Weed growth
• D. Water Temperature

Hint:

Chemical sealants for pond seepage reduction: Sodium polyphosphates (TSPP), Bentonite, Sodium carbonate. Cetyl alcohol is used for evaporation reduction.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Chemical soil sealants and dispersants reduce hydraulic conductivity and seepage through porous earthen farm pond beds by deflocculating clay aggregates.
Key Formula or Approach:
\[ K_{\text{dispersed}} \ll K_{\text{aggregated}} \]

Step 2: Detailed Explanation:
Tetrasodium polyphosphate (TSPP), sodium carbonate, and sodium chloride act as chemical soil dispersants (deflocculants).
When applied to the compacted bed of an unlined earthen farm pond, polyphosphate anions break down soil aggregates into individual clay platelets.
These fine clay platelets disperse and physically clog the inter-aggregate soil micropores, forming an impermeable colloidal blanket that drastically reduces seepage losses.

Step 3: Final Answer:
Hence, tetrasodium polyphosphate is used to reduce Seepage loss, matching option (B).