Stochastic Model of BOD and OD in Segmented Estuary

A one-dimensional stochastic model is developed for BOD and OD in streams and estuaries. The standard Dobbins type assumptions of first-order reaction, deposition, and reaeration rates are assumed, although any rate formulation is permitted by the analysis. The model parameters and process conditions have been made functions of position in the estuary and time in the tidal cycle. The predicted mean concentration is the same as for deterministic models based on the same assumptions. The predicted mean and distribution about the mean are compared with data from the Potomac Estuary and Ohio River with good agreement on the Potomac and excellent agreement with the Ohio data. With the Potomac data some lack of fit was observed due to photosynthesis and other effects occurring in the estuary which were not included in the mode.