Data Management Plan

During the spring of 1999, the Delaware Coastal Programs(DCP) identified the spatial extent of macroalgae in the shallow portions of Rehoboth Bay utilizing traditional photogrammetric methods. The DCP used true color aerial photographs, image processing software, a geographical information system (GIS), and a limited field survey to identify 1.88 square kilometers of macroalgae in all but the deepest parts of the bay. Turbid conditions prevented identification of the full extent of the vegetation.Although the 1999 effort was highly successful, it was clear that aerial photography could not penetrate to the deeper parts of the bay or where conditions were turbid.For the 2000 effort, the DCP partnered with the National Oceanic and Atmospheric Administration (NOAA) Office for Coastal Management Coastal Remote Sensing Program. The Benthic Habitat Mapping project, a part of the Center's Coastal Remote Sensing program, utilized a RoxAnn acoustic sensor to identify benthic cover in turbid areas of the bay June 12- 16, 2000.The instrument was used to identify bottom type by extracting data on bottom roughness and bottom hardness from the primary and secondary sounder echoes. The data is classified on-the-fly, using a towed video camera for field validation, and subject to a post-processing classification. The unit collected data throughout the bay in areas greater than 1.4 meters in depth and serves as a powerful complement to the aerial photography. The RoxAnn data points were exported into a geographic information system (GIS) and post-processed to remove unreliable data points and re-classified. This data set is comprised of the cleaned, attributed point data. The attributes include location, date, time, depth, field derived classification,and the classification derived from post-processing the data. This system is fully described in "Development of a System for Classification of Habitats in Estuarine and Marine Environments (SCHEME) for Florida, Report to U.S. EPA - Gulf of Mexico Program, Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute.Review Draft 12/04/02."

Original contact information:

Contact Org: NOAA Office for Coastal Management

Phone: 843-740-1202

Email: coastal.info@noaa.gov

Process Steps:

• 2000-06-19 00:00:00 - In June of 2000, the RoxAnn acoustic sensor was run in North-South and East-West transects across Rehoboth bay,recording geographically referenced point measurements of the acoustic data. The RoxAnn system analyzes two acoustic signals, bottom roughness (E1) and bottom hardness (E2).The ratios of these two measurements were calibrated in the field to known bottom types. Ground-truthing the measurements in the field was accomplished by under water video, grab samples and visual verification. The field database collected from June 12 - 16, 2000 was exported from the RoxMap software as a text file.Unreliable data points indicated by impossible bathymetry data were removed (i.e. depths in excess of 3 meters). In addition, series of identical points were reduced to the initial value and the remaining points from the data set.The fifteen original field derived classes developed in the field varied in level of descriptiveness: ulva; mud and algae; sand and algae; algae; gracilaria; gracilaria on mud; sand; bioturbated mud; shell/mud/algae; sandy mud;hard sand; mud with 15% algae; soft mud; mud and unknown.These overlapping and varying classifications were grouped to four general classes which comprised the bottom types observed equally general: algae (greater than 15%), mud(15% algae cover or less on soft mud), sand (15% algae or less on harder mud/sand) and unknown. The benthic data was then classified according to the System for Classification of Habitats in Estuarine and Marine Environments (SCHEME).This system is fully described in "Development of a System for Classification of Habitats in Estuarine and Marine Environments (SCHEME) for Florida, Report to U.S. EPA -Gulf of Mexico Program, Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute.Review Draft 12/04/02." These classes were then aggregated to either algae or no algae classes.