Monitoring a Nearshore Beneficial Use Site: Application of a Benthic Sled and Video Annotation
ERDC Vicksburg United States
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This technical note TN describes the U.S. Army Corps of Engineers USACE Portland Districts NWP application of 1 a benthic sled equipped with an image sensor and towed over a nearshore beneficial use site to monitor marine animals, 2 computational software used to annotate the video acquired by the benthic sled, and 3 automation of video annotation. BACKGROUND The NWP maintains safe and navigable waterways in Oregon through a variety of dredging projects, including channel deepening, and dredging sandbars. Placement of dredged sediment occurs at preselected, specific geographic areas. One such group of sites are categorized by NWP as nearshore beneficial use sites, these are used for the Mouth of Columbia River Federal Navigation Project MCR. Approximately 35 million cubic yards of sand is dredged annually from the MCR entrance channel to keep the deep-draft federal navigation channel open. Much of the dredged sand is placed at the nearshore beneficial use sites North Jetty and South Jetty Site, Oregon, this allows natural migration of the dredged sand through the Columbia River littoral cell Norton et al. 2015. Beneficial use sites are commonly monitored before, during, and after disposal, to evaluate dredge management practices and to avoid potentially adverse effects to the marine environment. The NWP, in collaboration with the National Oceanic and Atmospheric Administration NOAA, the U.S. Environmental Protection Agency Region 10, and the Oregon Department of Fish and Wildlife ODFW, regularly conduct site monitoring of the physical and ecological conditions of the placement sites. Ecological monitoring focuses on the survey of fish and epibenthic invertebrate species distribution and abundance. Surveys are conducted within, and outside the disposal area to assess changes in population or community structure, and to establish diversity indices for comparisons over time.
- Biological Oceanography
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