You should have a good working knowledge of your drainage systems.

Evidence for early agricultural drainage systems was found here, beginning about 9,000 years ago.

"You couldn't even design a drainage system that could take care of it."

Our drainage system is just not able to handle that amount of water.

Before long, both children are crawling through the drainage system.

Before the 2005 season, a new drainage system was installed on the field.

The city has had an underground drainage system since 1904.

We've more or less pinned it down to coming from the the drainage systems.

The area is under development and government sanctioned with drainage system.

The remains of this house give evidence to a sophisticated drainage system.