Probabilistic methods of hydrology and optimization techniques were used to determine an optimal sequence of releases from a system of reservoirs during a flood emergency. The operation schedule for a reservoir was determined from estimated inflow to the reservoir, current reservoir contents and downstream conditions. Linear programming was used to establish the optimal operating procedure. The duration of the flood producing storm was divided into a series of equal time increments, an inflow into each reservoir estimated for each time increment and a release made from each reservoir during each time increment. The objective function (to be maximized) was taken to be the sum of all reservoir releases during the duration of flood inflow to the reservoirs.