Barbados Relief, drainage, and soils

Mount Hillaby, the highest point in Barbados, rises to 1,102 feet (336 metres) in the north-central part of the island. To the west the land drops down to the sea in a series of terraces. East from Mount Hillaby, the land declines sharply to the rugged upland of the Scotland District. Southward, the highlands descend steeply to the broad St. Georges Valley; between the valley and the sea the land rises to 400 feet (120 metres) to form Christ Church Ridge. Coral reefs surround most of the island. Sewerage systems were installed in the late 20th century to address the threat to the reefs from runoff of fertilizers and untreated waste.

There are no significant rivers or lakes and only a few streams, springs, and ponds. Rainwater percolates quickly through the underlying coralline limestone cap, draining into underground streams, which are the main source of the domestic water supply. A desalination plant provides additional fresh water.

Barbados has mainly residual soils. They are clayey and rich in lime and phosphates. Soil type varies with elevation; thin black soils occur on the coastal plains, and more-fertile yellow-brown or red soils are usually found in the highest parts of the coral limestone.