 The existing dam had been built on alluvial deposits, which could liquefy during an earthquake.Accordingly, the estimated cost rose to US$400 million and the start of work was rescheduled to 2020, with completion planned for 2023–2024.After years of additional studies and interim actions, the Federal Energy Regulatory Commission dismissed the Water District's plans as insufficient to address the risk of catastrophic failure, and ordered on February 24, 2020 that Anderson Lake should be drained by October 1.