In pond construction drainage, what are the required trench dimensions and tile specifications?

• A. 6 inches deep by 6 inches wide trench with 4 inch diameter socked, perforated drain tile, covered with 4 inches of pea gravel
• B. 8 inches deep by 8 inches wide trench with 3 inch diameter non-perforated tile, covered with sand
• C. 4 inches deep by 4 inches wide trench with 2 inch diameter perforated tile, covered with gravel
• D. 12 inches deep by 12 inches wide trench with 6 inch diameter perforated tile, covered with soil

Answer: (A)

Drainage trench size and tile specifications in pond construction ensure water is carried away efficiently while preventing sediment from clogging the system. The recommended setup uses a trench that is 6 inches deep and 6 inches wide, with a 4-inch diameter perforated drain tile that is socked with fabric. Perforations in the tile let groundwater or runoff enter the pipe, while the fabric sock keeps soil from infiltrating and clogging the perforations. The tile is then backed with 4 inches of pea gravel, which provides immediate drainage space and acts as a filter to keep fine particles from entering the pipe, yet still allows water to move freely. This combination balances practicality and effectiveness for pond drainage, avoiding choices that use non-perforated tile, incorrect tile size, or inappropriate backfill such as sand or soil, which can hinder drainage or promote clogging. The other options either misalign the drainage flow with non-perforated tile, use an unsuitable tile diameter for the expected load, or backfill with materials that reduce permeability or invite sediment intrusion.