trong>Narrator: This is Science Today. Water quality has always been a challenge when planning irrigation in arid regions – not only in terms of finding suitable quality water for crops, but also when it comes to the disposal of drainage water. University of California Cooperative Extension irrigation and water management expert, Khaled Bali, is working to address these issues in the southeastern corner of California known as the Imperial Valley.

Bali: The only source of irrigation water here in the Valley is Colorado River water. And we use about 20% of the annual yield of the river. On average, we have about 15 million acres feet of water and we use here down in the Valley, there million acre feet.

Narrator: About one-third of applied irrigation water leaves fields as surface runoff that eventually flows into the Salton Sea – the largest inland body of water in California. This runoff threatens fish and wildlife, so Bali has developed improved irrigation practices.

Bali: The way we're doing it is by minimizing the amount of surface runoff at the same time we reduce the subsurface drainage.

Narrator: For Science Today, I'm Larissa Branin.