Some plants built on an ocean or large river simply pump in large amounts of water to cool the steam. This cooling water then is returned back to the ocean or river. The water is somewhat warmer than when it entered the plant. If the cooling water is discharged to a significant water body, such as an ocean, lake, or major river, the water can be discharged directly. However, if the water is discharged to a river, its return to the river may be delayed by routing it through a canal or cooling pond first.
Some plants recycle cooling water.
Cooling ponds and towers are used to transfer the heat in the cooling water to the air. A cooling pond is a shallow reservoir having a large surface area for removing heat from water. The surface area exposed to the air may be increased through the use of spray nozzles. Cooling ponds are used where land is relatively inexpensive, cooling water is scarce or expensive, or where there are strict thermal loading restrictions in place. If cooling ponds are used, water in the pond can be reused, thus reducing the overall water-withdrawal requirement.