Scripps Project Analyzes Movements of Beach Pollution


American Geophysical Union, Fall Meeting 2008

In an attempt to better decipher the dynamics of the shoreline and especially how pollution and contaminants travel and intermingle at the beach, scientists at Scripps Institution of Oceanography at UC San Diego this fall launched a new project off the San Diego coast.

Researchers released pink dye off the La Jolla, Calif., coast to better understand how pollution moves and mixes in the surf zone.

Scientists deployed a bank of instruments mounted on a 400-pound frame off La Jolla, Calif., to capture a stream of near-real-time data about surf zone dynamics, including how waves break and dissipate their energy.

"When stuff gets put into the water, whether it's bacteria from sewage spills or some other substance in surf zone waters, we'd like to know how it moves, mixes, spreads and dilutes," said Falk Feddersen, an associate research oceanographer at Scripps.

Feddersen will describe the project at the 2008 American Geophysical Union Fall Meeting in San Francisco (Monday, Dec. 15 at 12:05 p.m. · Moscone West Room 2022).

The instrument frame deployed by a team of engineers and technicians included Doppler velocimeters that measure currents and sensors that measure wave height, water temperature and sand level. Fluorescence meters at four vertical levels determined the concentration of a bright, non-toxic pink dye the researchers released into the water. Tracking the dye helps the scientists get a better picture of how pollution moves and mixes in three dimensions: along the coast, offshore and vertically.

All of the information was measured and recorded eight times per second, pumping upwards of 40 megabytes of data per hour to the project's information center just up the beach on the Scripps campus.

On Oct. 22, 2008, Scripps researchers deployed a suite of instruments mounted on a frame just north of the Scripps Pier.

The research will continue to improve upon the decades-long quest by Scripps coastal oceanographers to more fully understand complex processes along the coast. The new results, the researchers hope, will help coastal managers improve beach closure decisions that can impact tourism and related economic concerns.

"This project is part of an ongoing study to understand the transport and dilution of pollution in the surf zone," said Bob Guza, a Scripps professor of oceanography. "We're learning more about how pollution, especially urban runoff, mixes and disperses in the surf zone."
The project is supported by the National Science Foundation and Office of Naval Research.

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Video related to the project is available.

•For more information see Scripps' explorations e-magazine feature story: Beach of the Future

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