Harbor pollution from large ships

Abstract

Problem:

Develop data to ascertain the magnitude of the sewage pollution problem arising from Navy ships anchored in or moving through a harbor, with particular reference to amphibious training exercises in which large numbers of personnel may be brought to nearshore areas for relatively short times.

Results:

A number of releases of dyed sewage were made in Wilson Cove Harbor of San Clemente Island at rates corresponding to those at which sewage would be discharged by amphibious task forces of from 500 to 10,000 men. The movement of the sewage was traced by photography, bacterial counts, dye, and BOD measurements in the surrounding water and on the shoreline. The results show that the diffusion (rate of spreading) of the sewage was much lower than that predicted from open-ocean data, and hence Navy ships can stay in a small harbor, such as Wilson Cove, much longer than originally anticipated without danger of sewage contamination of the shoreline. An operational-guidance chart was constructed indicating those times and minimum distances for a given manning level of a task force that would prevent contamination of the shore.