文摘
The surf zone is the unique environment where oceanmeets land and a place of critical ecological, economic,and recreational importance. In the United States, this naturalresource is increasingly off-limits to the public due toelevated concentrations of fecal indicator bacteria andother contaminants, the sources of which are often unknown.In this paper, we describe an approach for calculatingmass budgets of pollutants in the surf zone from shorelinemonitoring data. The analysis reveals that fecal indicatorbacteria pollution in the surf zone at several contiguousbeaches in Orange County, California, originates from well-defined locations along the shore, including the tidaloutlets of the Santa Ana River and Talbert Marsh. Fecalpollution flows into the ocean from the Santa Ana River andTalbert Marsh outlets during ebb tides and from there istransported parallel to the shoreline by wave-driven surfzone currents and/or offshore tidal currents, frequentlycontaminating >5 km of the surf zone. The methodologydeveloped here for locating and quantifying sources of surfzone pollution should be applicable to a wide array ofcontaminants and coastal settings.