Bystanders were met with the rumble of rushing water as Oroville Dam’s gates released millions of gallons of water down a newly reconstructed concrete spillway on Tuesday for the first time since the structure failed two years ago. In February 2017, people who live downstream in Oroville watched in disbelief as millions of gallons of water eroded the main spillway of the nation’s tallest dam, sending a deluge of water cascading down a hillside and forcing thousands of residents to evacuate. That scenario was exactly what bystanders watching the first water flow from the newly rebuilt spillway hoped to avoid.