Profiles of six water quality parameters were obtained in the vicinity of a major ocean outfall discharge near Los Angeles, California and used to trace the extent and direction of travel of the submerged wastewater field. Using a high speed digital data acquisition system, profiles of each water quality parameter are continually measured to high precision and recorded in ASCII code on mylar tape at intervals of up to 3 times per second. A computer and incremental plotting system are used to plot profiles to graphically represent the degree the wastewater field influences each parameter. A determination of the extent of the wastewater field was made by comparing each water quality parameter observed in the vicinity of the discharge to those parameters measured at control stations remote from the discharge. Parameters measured during several field surveys of wastewater and sediment dredge spoil discharges include temperature, specific conductivity, dissolved oxygen, pH, and percent light transmittance. Using this method, the extent and direction of travel of effluent fields have been traced as far as 3 miles away from the point of discharge.