Central Washington's Yakima Valley sits on the dry side of the Cascades, where just eight inches of precipitation falls each year. But the arid valley has rich volcanic soils and an accommodating climate of warm days and cool nights, and after the U.S. Bureau of Reclamation built six dams in the early 20th century, farms and orchards flourished here. Thanks to the water brought via pipes and canals, the Yakima region became known as the nation's "Fruit Bowl." Today, apple, pear and cherry trees cover 92,000 acres, and wine grapes spread over another 10,000. The valley also produces three-fourths of the country's hops, a $100 million crop. In recent years, though, the region has reaped a different bumper crop. Since 2000, the city of Yakima has added 12,000 new residents  -- a 17 percent jump in population  -- and the valley is thirstier than ever. That's a familiar story