| Title: Great Bay Estuary Eelgrass, 2017 | |
| Time Period of Content: August 24, 2017 | Initial Publication Date: 1986 |
| Originator: Seth Barker, Independent Contractor | |
| Abstract: The dataset was developed to monitor the distribution of eelgrass within the Great Bay Estuary over time. The surveys have been completed yearly since 1986 to track trends over time. A final report on the project is available here. The dataset shows the locations where eelgrass was observed in the Great Bay Estuary based on photointerpretation of orthophotography collected on August 24, 2017. The study area includes the following waterbodies: Great Bay, the mouth of the Squamscott River, the tidal portion of the Lamprey River, the tidal portion of the Oyster River, the tidal portion of the Bellamy River, the Piscataqua River and Portsmouth Harbor and its associated creeks. Vertical aerial photograph was collected as digital 4-band imagery with a nominal 1 foot resolution using a Intergraph Digital Mapping Camera. Environmental conditions included a low sun angle, low spring tide, low cloud cover, calm winds, no preceeding rain events, and low turbitiy in the water column. The eelgrass habitat mapped from the aerial imagery was verified using the ground truthing data from preselected locations and ad hoc locations chosen during the course of the field work. Ground truthing was done from a small boat during the same season as the photographs are taken. Ground truth observations were made on all tides using a drop camera with video recording capabilities and at low tide when visual observations were recorded. Positions are determined using high accuracy Trimble GeoXH and GeoXT GPS units and a Garmin Colorado 400c as a backup. More eelgrass layers can be viewed on the NH DES eelgrass viewer. | |
| Theme Keywords: biota, Eelgrass, Estuary, Estuarine | |
| 1986 Full Metadata and Data Download 1996 Full Metadata and Data Download 2017 Full Metadata and Data Download | |