Final answer:
When placing a perforated pipe with the feed holes facing down, it is important to line the bottom of the trench with a material that allows water to pass through but prevents soil clogging.
Step-by-step explanation:
When placing perforated pipe with the feed holes facing down, it is important to first line the bottom of the trench with a material that allows water to pass through but prevents the surrounding soil from clogging the holes. This material can be a geotextile fabric or a layer of gravel or crushed stone.
A geotextile fabric acts as a filter, allowing water to flow through while preventing soil particles from entering the pipe and causing clogging. It is important to use a strong and durable fabric that can withstand the load of the surrounding soil.
Alternatively, a layer of gravel or crushed stone can be used to line the bottom of the trench. This provides a porous and stable base for the pipe, allowing water to pass through while preventing soil particles from entering.