isušiti

1. (of a swamp, lake) to drain; to dry up
   Močvaru su isušili pre pedeset godina. — The swamp was drained fifty years ago.
2. to dry out; to parch
   Sunce je potpuno isušilo zemlju u bašti. — The sun completely parched the soil in the garden.
   Ovaj šampon mi je isušio kosu. — This shampoo dried out my hair.

For a river or spring drying up by itself, isušiti se or presušiti is used.