Final answer:
The soil removed from the trench for a subsurface drainage structure can be reused to backfill the trench or stockpiled for future use. This ensures the original soil composition and structure are maintained.
Step-by-step explanation:
When you dig a trench for a subsurface drainage structure, the soil removed from the trench should be properly managed to prevent any negative environmental impacts. One option is to reuse the removed soil to backfill the trench after the drainage structure is installed. This helps to maintain the original soil composition and structure, reducing the risk of erosion or soil compaction. Alternatively, the removed soil can be stockpiled for future use or relocated to other areas where it may be needed.