NONTHABURI, Thailand—Riverside restaurant owner Titiporn Jutimanon was convinced a bout of flooding in Thailand could be the end of a business already struggling from the pandemic. But with the rising tide of the Chao Phraya River this week came an unexpected opportunity. Instead of closing for the floods, Titiporn’s eatery is making waves in Thailand, staying open for customers who are reveling in shin-deep dining, and the thrill of avoiding the rush of water set off as boats go by. “Customers absolutely love the waves,” said Titiporn, who runs the Chao Phraya Antique Cafe in Nonthaburi, north of Bangkok. “What I thought would be a crisis turned into an opportunity.” Videos have gone viral on social media of customers sitting on drenched chairs, taking mouthfuls of food as long-tail boats buzz by, then moving out of the way as waves hit. About 30 northern and central provinces have been hit …