SS1.01 Assessing Potential Environmental Impacts of Aquaculture
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
Kyte, M, A, Golder Associates Ltd., Seattle, USA, mkyte@golder.com
MundayDR, Golder Associates Ltd., Victoria, Canada, dmunday@golder.com
Lemieux, G, D, Golder Associates Ltd., Victoria, Canada, glemieux@golder.com
 
A WIDE AREA RAPID ASSESSMENT TECHNIQUE FOR BENTHIC HABITATS
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Offshore geophysical survey methods provide a rapid and cost-effective tool for environmental assessment of coastal zones, estuaries, rivers, lakes, and other water bodies. Mapping of benthic habitat and subsurface geology by Golder Associates Ltd. is done from small vessels of opportunity using an integrated combination of side-scan sonars, single or multibeam echosounders, subbottom profilers, underwater video, and the differential global positioning system (DGPS). Surveys conducted to map submerged aquatic vegetation using underwater video can miss important features such as abandoned outfalls, partially buried cables, recreational vessel mooring anchors, and rock outcrops. In addition, video surveys can misrepresent patchy conditions. For the aquaculture industry, this can cause problems with alignment, site selection, and impact mitigation planning. A side-scan sonar survey, integrated with video images to verify species composition and signal interpretation and real-time DGPS for precise positioning, provides a comprehensive high-resolution map of actual conditions over a relatively large area. This poster presents results from recent marine geophysical surveys conducted to map and select a route for a proposed fiber optic cable in the San Juan Archipelago, Washington.