The critical document that determines how much space should be left in Lake Oroville for flood control during the rainy season hasn’t been updated since 1970, and it uses climatological data and runoff projections so old they don’t account for two of the biggest floods ever to strike the region. Independent experts familiar with the flood-control manual at Oroville Dam said Wednesday there’s no indication the 47-year-old document contributed to the ongoing crisis involving the dam’s ailing spillways. The current troubles stem from structural failures, not how the lake’s flood-storage space was being managed.