Design of Sewage Lagoons Using Stochastic Streamflow Sequences

Abstract

A risk‐based design procedure for hydrograph‐controlled release sewage lagoons is derived. This procedure is based on a stochastic analysis of flood interarrival time, duration, and volume. By modeling streamflow as a Poisson counting process, stochastic sequences consisting of maximum interarrival times and minimum duration are constructed. These sequences are used as the basis for lagoon design by calculating their recurrence intervals based on the joint probability of exceedance of the components of the sequence. Sequences such as those derived here are shown to occur in nature.