lay perforated pipes below the level of cultivation, which is usually around 40cm to 60cm deep and 3m to 6m apart,' Jess says. 'The trenches for piped drainage should follow a natural slope or a ...

Drain lines require a downhill slope of at least 1/4 inch per linear foot so that waste flows smoothly through the pipes. The depth of the main line at the tie-in point determines the maximum ...