A 330-megawatt data center proposed in the Imperial Valley would need 750,000 gallons of water a day. Satisfying the thirst of 24 more facilities expected to open in the state by 2030 will be challenging, experts and officials say.By Steven RodasIMPERIAL, Calif.—The new data center proposed for a quiet city about 115 miles east of San Diego came across people’s radars in different ways.