Using a combination of side-scan sonar and underwater videography, researchers at Pacific Northwest National Laboratory have successfully characterized a large section of shoreline habitat on Washington's Puget Sound. "This is the first time anybody has developed a comprehensive, continuous map of a large section of shoreline with this combined technique," said Dana Woodruff, project director at Pacific Northwest's Marine Sciences Laboratory.
Researchers acquired sonar images and video data for nearly 14 miles of shoreline to assist the King County Department of Natural Resources in determining the location for its new wastewater treatment plant outfall. Using the combined equipment, researchers identified and characterized the substrate, vegetation and fisheries resources to determine an area of least environmental impact.
According to researcher Ron Thom, King County was pleased. "They said it was the most useful product they've gotten on near-shore characterization," Thom said. "And our effort has helped them to narrow down the location for siting the outfall to a few sites with the least environmental impact."
In addition to creating baseline maps and identifying potentially sensitive areas, the assessments are useful for determining future restoration scenarios and other applications.
The combined technologies of sonar and video provide much greater accuracy and detail in characterizing shallow water habitats than more traditional methods such as diver transects or video alone. Researchers are continuing to work on system refinements that will save time, such as neural-network-based pattern recognition capabilities that would automatically characterize and extract features from the sonar imagery in the near-shore environment. A neural network is a matrix of electronic neurons that imitates a biological brain.
Development of this new system, managed by Karen Steinmaus, is a joint U.S. Department of Energy and National Imagery and Mapping Agency project.
Special thanks to Sue Chin, contributing writer.