Drainage basins are separated from each other by an area of higher ground called a drainage divide. North America has 5 large Continental Divides that separate the drainage basins of the Pacific, Arctic, and Atlantic Oceans, Hudson Bay, the Great Lakes, and the Gulf of Mexico.

The countries drainage system is a river that collects water in a drainage basin. It also may be called a Himalayan or Peninsular drainage.

Drainage basins are separated from each other by an area of higher ground called a divide.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.

Roads were/are built with ditches for drainage purposes.