Reaeration Coefficients of Streams—State-of-the-Art

Techniques for measuring and equations for predicting the natural reaeration coefficients of streams were reviewed. The three basic procedures for measuring the reaeration coefficient of streams are the dissolved-oxygen balance, the disturbed equilibrium, and the tracer techniques. The tracer technique has the advantage that it does not require the measurement of any of the sources and sinks of dissolved oxygen in the stream. The various predictive equations available in the literature give a wide range of predicted coefficients for a specific set of hydraulic conditions. Application of these equations to five streams for which reaeration coefficients had been measured with the tracer technique showed that no one equation is best for all the streams. Progress is being made in the development of techniques for measuring and predicting reaeration coefficients of streams, however, further research is needed.