NOS scientists deployed Global Navigation Satellite System receivers at fixed marks on Poplar Island, and on the mainland, to connect various land- and water-based observation systems to the National Spatial Reference System.
The NOS scientists who are most often thought of as providing navigation services are also steering the nation toward more conscientious uses of the marine environment. Staff from NOS’s National Geodetic Survey, Office of Coast Survey, and Center for Operational Oceanographic Products and Services are working with the U.S. Army Corps of Engineers (USACE) to provide an integrated suite of data products to help guide the reconstruction of Poplar Island in a manner that provides sustainable wildlife habitat for years to come.
Poplar Island provides habitat for many birds and waterfowl, included this unexpected visitor – a Snowy Owl.
Lying just a few miles west/northwest of the historic fishing village of Tilghman Island on Maryland’s Eastern Shore, Poplar Island represents a bold experiment in the beneficial application of dredge material. Although much of the island had eroded away by the late 20th century, material recovered as part of normal dredging operations along the approach channels to the Port of Baltimore is now being used to restore Poplar Island to its original size.
As part of the restoration, 230 hectares (about 570 acres) of wetlands and protected shallow-water embayments are planned to provide habitat to resident and migratory animals and birds. Poplar Island is a midpoint in the Atlantic Flyway along the U.S. East Coast, and, as such, it is a “popular island” with a wide variety of migratory waterfowl (e.g., Canada Geese, Canvasback and Redhead Ducks) and other birds that winter on the waters and marshes south of Delaware Bay.
Although the restoration project is only partially completed, numerous diamondback terrapins – the only North American turtle species that lives in brackish water (where fresh- and saltwater mix) – are also being observed at Poplar Island. Some experts think the East Coast terrapin population is on the decline due to such factors as the destruction of nesting beaches, turtles drowning in eel and crab pots, excessive predation, and commercial harvesting.
An illustration of the survey control marks included in NOAA’s Height Modernization survey of Poplar Island.
The success of the reconstruction project hinges largely on the USACE’s ability to grade the dredged sediments to the appropriate elevation with respect to local sea levels, and to provide a mechanism for naturally occurring sediment deposition. Scientists from NOS’s National Geodetic Survey are providing their expertise to deploy Global Navigation Satellite System receivers at fixed marks on the mainland, and at marks established on the island, to connect various land- and water-based observation systems to the National Spatial Reference System. This is a consistent coordinate system specifying latitude, longitude, height, scale, gravity, and orientation throughout the nation.
At the same time, the Office of Coast Survey is contributing a finely resolved circulation model as part of NOS’s new Chesapeake Bay Forecast System, and the Center for Operational Oceanographic Products and Services is collecting data on tides and water levels to create a tidal datum – a standard elevation used as a reference to measure local water levels.
As a result, USACE will be able to monitor surface elevations of the island’s constructed wetlands as local sea levels change. This information will help scientists and engineers as they strive to sustain the reconstructed habitats over time.
So while birds, turtles, and other creatures might not need any help navigating as they roam the mighty Chesapeake, the scientists on NOS’s “navigation side” are helping restore one of their preferred stopping points along the way.