The river furnishes water for irrigating the low fields in the vicinity.
In early times irrigating canals distributed the waters over the plain, and made it one of the richest countries of the East, so that historians report three crops of wheat to have been raised in Babylonia annually.
A project for irrigating the district south of the mountains between Ponce and Patillas was adopted by the Porto Rican government in 1909.
The great bend of the river affords easy irrigation, and the surrounding country is covered by a network of irrigating canals, even the paved streets of the town having streams of cool water running through them.
The sugar farms are mostly on the islands of Hawaii, Oahu, Maui and Kauai, at the bases of mountains; those on the leeward side have the better soil, but require much more irrigating.