Flood Storage Allocation Rules for Parallel Reservoirs

Optimal operating policies have been derived for reservoirs in series and in parallel for various purposes, but little formal analysis has been done for flood operation of parallel reservoirs. For flood management, parallel reservoir releases should be managed together to reduce downstream peak flow and minimize flood damage. The optimal allocation of total available flood storage capacity among parallel reservoirs should have each reservoir’s flood storage allocation providing the same incremental reduction to downstream flood flows. This approach is developed mathematically and applied for deterministic and probabilistic inflows. The applicability and effectiveness of these derived flood storage allocation rules are demonstrated by the case study of Oroville Reservoir and New Bullards Bar Reservoir in California’s Sacramento River Basin with a single historical 1997 flood and an uncertain storm.