Trench drains may be precast or cast-in-place. Figure 10-6 illustrates the body and grate of an installed precast trench drain.

Trench drains have the advantage of a shallower embedment depth and an extremely smooth invert that doesn’t retain sediments, but the disadvantage of having a limited volume because of their size.

Trench drains on Department roadways are required to have non-removable grates because removable grates may come loose or move which will create a traffic hazard. The grates specified by the Department have a minimum of 60% open space which allows for cleaning with a vacuum truck or water truck without removing the grates.