The Grade
Categories:
DRAINAGE
The outlet may fix the grade. If it does not, the main,
branches, and laterals should have a fall of 3 inches, or more, to the
100 feet. This grade insures against deposits of silt and gives good
capacity to the drains. If the outlet demands less fall in the system,
the main may be laid on a grade of only a half inch to the 100 feet
with satisfactory results. Such a small fall should be accepted only
when a lower outlet cannot be secured, and great care should be used in
grading the trench and laying the tile.