A water manager who led the state’s emergency response to the erosion of the nation’s tallest dam says he’s retiring. Acting Director Bill Coyle made the announcement Friday after nearly a decade with the California Department of Water Resources. The 59-year-old had planned to retire in January, when Gov. Jerry Brown asked him to lead the department. The following month, the spillway at Oroville Dam crumbled when water overflowed during one of the state’s wettest winters on record. Nearly 200,000 residents downstream were ordered from home. His department is also shepherding plans to build a massive pair of $16 billion water tunnels.