In recent years, many mathematical models have been developed to be used as mechanisms for carrying out stream and estuary investigations. In 1971, W.R. Schofield and R.G. Krutchkoff completed work on a stochastic model in an attempt to accurately describe the behavior of an estuary. Through the use of a high-speed computer this one-dimensional model predicts the concentrations of twelve interacting components, subdivided into five biological and seven chemical factors. This is a valuable tool, but from a practical viewpoint, the model is difficult to apply without a fairly strong background in computer science. It is the aim of the present study to simplify the use of the SchofieldKrutchkoff estuary model so that it can be readily accessible to the appropriate personnel, irrespective of their previous exposure to computer programming. Dependent upon the particular estuary studied, it was necessary to make internal program adjustments with respect to boundary conditions, applicable rate constants, tidal lag, and maximum tidal velocity rates. These constants have been replaced by variables for the user to define as input data to the main program segment. The options to choose one of several expressions for the oxygen reaeration rate K₂, whether to weight this equation with wind velocity, vary the volumetric freshwater flow rate with position and request plotted output for each day modeled have also been added. / Master of Science