Hydraulic model studies were made of the waste dispersion characteristics of San Francisco Bay. The effects of several proposed salinity control barriers on these characteristics were investigated. A fluorescent dye tracer, Pontacyl Brilliant Pink B, and the G. K. Turner Associates Fluorometer were used. Using the results of the model studies, estimates were made of the effect of existing and future waste loads on the oxygen resources of the Bay. When applied to existing waste loads, the calculated general description of dissolved oxygen levels agreed favorably with observed conditions. It is concluded that the test procedures provide a suitable basis for estimating the effect of proposed changes in the Bay system on water quality and for determining the associated treatment and disposal practices necessary to meet desired water quality objectives. The use of the hydraulic model results in a significant saving of both time and expense.