Great Bay Estuary Eelgrass, 2022

The dataset shows the locations where eelgrass was observed during the 2022 field season within the following water bodies: 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, and the coastal shore of Odiorne Point. Photointerpretation was completed on orthophotography collected using a UAV over the study area. Sentinel satellite imagery was also used to further complement these datasets to help with photointerpretation. GoPro camera aerial imagery was also taken from a small plane over the whole of the study to further complement the photointerpretation of the imagery. UAV imagery was collected as five spectral bands inclusive of RGB, Red-Edge ,and Near Infrared bands. Imagery was collected with varying 1.7 to 3.4 cm spatial resolutions based on 100 to 400 ft flight altitudes specific to FAA maximum flight restrictions around the Pease International Tradeport. The Sentinel satellite imagery was acquired for the date of August 2nd, 2022 with a nominal 10-meter spatial resolution. The GoPro imagery captured non-rectified true-color photographs. Environmental conditions including low-sun angles, low tides, low cloud cover, calm winds, no preceding rain events, and low turbidity in the water column, were maintained throughout the course of the UAV survey when possible. The eelgrass habitat mapped from the 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 were 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.