Investigation of Beach Contamination Using Tracer

Abstract

To investigate the potential contamination of a public beach by a nearby duck pond in Marina Del Ray, California, rhodamine B dye is introduced to the pond effluent during an ebb tide. Water samples are collected to measure the transport and dispersion of the tracer during the following three days (13 tidal cycles). Concentrations of fecal coliforms in the harbor are measured for high and low tide. A mathematical model is applied to simulate the water movement and the transport of the tracer in the harbor, and between the harbor and duck pond. The probability for duck‐pond effluent to contaminate the public beach is small. The complementary use of field programs and mathematical modeling is effective in providing a definitive answer to the beach contamination problem.