USGS - science for a changing world

Pacific Coastal & Marine Science Center

This is an abstract from the 1993 Geological Society of America Annual Meeting in Boston, Massachusetts.

Seafloor Mapping and Characterization: Application of Basic Marine Research to Environmental Management of the Urban Ocean

Herman A. Karl, John L. Chin, William C. Schwab, Edward Ueber and Alan Y. Ota

As part of an ongoing strategic research project to find barrels of radioactive waste off San Francisco, the U.S. Navy (USN), the U.S. Geological Survey (USGS), and the Gulf of the Farallones National Marine Sanctuary (GFNMS) pooled their expertise, resources, and technology to form a partnership to verify new computer enhancement techniques developed for detecting targets the size of 55 gallon barrels on sidescan sonar images.

Between 1946 and 1970, approximately 47,800 large barrels and other containers of radioactive waste were dumped in the ocean west of San Francisco; the containers litter an area of the sea floor of at least 1400 square km known as the Farallon Island Radioactive Waste Dump. The exact location of the containers and the potential hazard the containers pose to the environment is unknown. The USGS developed computer techniques and contracted with private industry to enhance sidescan data, collected in cooperation with the GFNMS, to detect objects as small as 55 gallon steel barrels while conducting regional scale sidescan sonar surveys. Using a subset of the regional sonar survey, locations of probable 55 gallon barrel size containers derived from the enhanced sidescan sonar images were plotted over a 125 square km area. The acoustic interpretations were verified visually using the USN DSV Sea Cliff and the unmanned Advanced Tethered Vehicle (ATV). Barrels and other physical features were found where image enhancement had indicated they would be found. This is the first successful test of locating barrels by regional-scale mapping, and in that regard represents a breakthrough. Any previous attempt to locate the barrels using submersibles was akin to trying to find a needle in a haystack. In contrast, using the new acoustic maps to drive from one barrel site to the next, each Sea Cliff and ATV dive verified the predicted absence or presence of barrels.

The interagency cooperation among the USN, USGS, and GFNMS has led to develop a cost effective and time efficient method to locate the barrels of radioactive waste. This method has universal application for locating containers of hazardous waste over a regional scale in other ocean areas such as Boston Harbor and the Kara Sea in the Arctic. This successful application of military and civilian expertise and technology has provided scientific information to help formulate policy decisions that affect the environmental management and quality of the ocean.

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