A legal battle is raging in Bay Area courts over a landowner’s plans to transform an island in the Delta into a playground for Silicon Valley. Secluded Pt. Buckner Island in Suisun Bay has become well known for its kite-surfing and other sports. When John Sweeney bought the small Delta island, it was in pretty bad shape. The levees were breached in several places, allowing water to cover part of it. As the new owner, Sweeny says “by law” the Suisun Marsh Preservation Act now makes that his problem. “When you buy the property, you have a compliance period where...