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Archived Hydrographic Smooth Sheet And Bottom Sample Recovery

By Daniel Neumann

Hydrographic survey metadata development at NOAA's office of Coast Survey has evolved from a localized operation to an open and integrated database in cooperation with NOAA's National Geophysical Data Center (NGDC). Coast Survey, in partnership with NGDC, is recovering bottom sample data to help researchers and planners with marine habitat study, geologic research, coastal zone management and analysis of environmental change. The samples may help them understand the impact of benthic habitat on fisheries and other biological communities, for instance, how sediment texture potentially influences distribution and population size of ground fish. The samples also identify dredged material for beach replenishment, help estimate the impacts of events related to slope activity and are useful in locating offshore mineral resources. Coastal managers can use the sample data to determine sites for seabed communication cables, drilling platforms and other structures as well as proposed sites for offshore waste disposal. The samples also aid in environmental prediction as surrogates of past climate change, ground truth for remotely sensed data, and identification of the extent, nature and transport of pollutants.

Smooth sheets, the final plots of hydrographic surveys, are a snapshot of the best bathymetry at the time. They provide a historic record of coastal shoreline and water depth, and thus are critical in historic analysis of shoreline movement and depth changes. Studying surveys of a specific area can assist with documentation of shoreline migration and erosion. The changes in water depth point to sedimentation or deepening from natural processes like onshore currents or storms.

The smooth sheets may become legal documents in state and local government boundary disputes. The bathymetry can help predict areas of high coral abundance and diversity in order to protect that resource and can help the fishing industry's stock assessment for bottom trawling. A case in point is the use of smooth sheets in the Aleutian Islands and Gulf of Alaska where NOAA's National Marine Fisheries Service has used the data to outline areas that are too steep and rough to trawl.

There are currently more than 600 United States hydrographic surveys that have not been scanned and more than 300 bottom-sample forms that have not been compiled. This total includes more than 130 coastal smooth sheets, more than 280 Great Lakes smooth sheets and at least 120 smooth sheets that need repair.

The recovery of missing scans of hydrographic smooth-sheet and bottom-sample metadata are ongoing projects. Coast Survey, with cooperation from the National Archives and Records Administration (NARA), is committed to providing users with scanned images of the missing surveys. However, there are a small number of oversized and damaged surveys which currently cannot be scanned and may not be able to be completely recovered. Likewise, Coast Survey, in cooperation with NGDC is determined to provide full bottom-sample coverage from all available NOAA hydrographic surveys.

NGDC stores many products associated with hydrographic surveys. These products include smooth sheets, descriptive reports and bottom-sample listings. An exhaustive comparison of the latest Coast Survey inventories at NARA, with captured images at NGDC, identified more than 600 smooth sheets dating from 1830 to 2004, which have not been scanned. More than 300 survey bottom samples dating back to 1963 have not been converted to ISO compatible information. There are also more than 100 surveys from a variety of regions that will require restoration before they can be scanned. An additional 112 smooth sheets, inventoried in 1994 at a NOAA vault facility in Riverdale, Maryland, do not appear on the NGDC product lists. NARA is verifying their availability for scan. If Coast Survey determines that these 112 sheets should be scanned, they will be incorporated into the tracking list and scheduled for scanning. To continue this article please click here.

Daniel Neumann has worked with NOAA's Office of Coast Survey since 1974. He is a senior information technology specialist in the Hydrographic Surveys Division. With Lt. Cmdr. Gregg Glover, he created the Hydrographic Survey Metadatabase in 2004. In 2010, he completed development of the Rap Sheet addition to the hydrographic survey product list. In 2012, together with National Geophysical Data Center's Carla Moore, he began adding missing Rap Sheet bottom samples to the survey products from recovered M Logs.

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