GRANIT Metadata for Great Bay Estuary Eelgrass, 2019
GRANIT Metadata for Great Bay Estuary Eelgrass, 2019
Title:
Great Bay Estuary Eelgrass, 2019
Time Period of Content:
August 2, 2019
Publication Date: April 27, 2020
Originator: Seth Barker, Independent Contractor
Abstract:
The dataset shows the locations where eelgrass was observed in the Great
Bay Estuary based on photointerpretation of orthophotography collected on
August 2, 2019. 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
photography was collected as digital 4-band imagery with a nominal 1 foot resolution
using an Zeiss DMC IIe 230 Mapping Camera. Environmental conditions included
a low-sun angle, low spring tide, low cloud cover, calm winds, no preceding rain
events, and low turbidity 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 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. Positions were
determined using high accuracy Trimble GeoXT GPS unit.
