For three decades, Georgia and Florida have been battling over how to share a precious resource: water. Georgia has it, and Florida, which is downstream, says it’s not getting its fair share. The dispute is once again headed to the U.S. Supreme Court, where Florida wants the justices to cap Georgia’s water use. But a court-appointed special master recently rejected that idea.

More than 6 million people depend on water that starts at Lake Lanier, a reservoir northeast of Atlanta. It generates hydropower as its water is released from a dam into the Chattahoochee River.