Horn Point Project
Washington College partnered with the University of Maryland’s Horn Point Laboratory to help in a project studying Poplar Island, an island located one mile offshore of St. Michael’s, Maryland.
Island History: In the early 1990s, the United States Army Corps of Engineers (USACE) conducted a follow-up survey of the island and discovered that it had eroded to a measly four acres of its original 1100 acre size. Over the past 100 years, the island had gradually lost land due to water currents and increasingly intense storm events. After discovering this, USACE, along with other Maryland-based partners, like Maryland Environmental Service and the Maryland Department of Natural Resources, took proactive steps to preserve the remaining acreage and begin drafting a plan to rebuild the island to its original size and shape. For context, this is one of the largest artificial wetland projects to ever be undertaken!
Above: Historic navigation chart of Poplar Island from 1860 from the National Oceanic and Atmospheric Administration (NOAA).
Above: Historic navigation chart of Poplar Island in the 1990s, also from NOAA, showing considerable erosion of the island.
The island is being rebuilt using dredge material from shipping channels that intersect the Bay Bridge. To make the project more manageable for the engineers, the island was split into sixteen smaller cells, in order to track progress and organize the project. As the cells were filled with dredged materials, they are then planted with a native salt marsh plant, Spartina alterniflora, more commonly known as smooth cordgrass. This plant is being used to stabilize the dredge material and create wildlife habitat in the low marsh sections of the island, which make up approximately 40% of the island’s area.
Above: An outline of Poplar Island, broken down into the sixteen cells, six of which are being studied by this project: 1A, 1B, 1C, 3A, 3D, and 4D.
Project History: The island is being rebuilt using dredge material from the Bay and has been in progress since 1998. The island was split into smaller cells, in order to track progress and organize the project. As the cells were filled with dredged materials, they are then planted with Spartina alterniflora, a smooth cordgrass, which is used to stabilize the dredge material and create wildlife habitat.
Our involvement: The GIS laboratory took this project on in early 2015 with a goal to create a methodology for tracking cordgrass growth in the six finished cells (1A, 1B, 1C, 3A, 3D and 4D) over a period of six years: 2011 through 2016.
As the cells are completed, we are using multispectral satellite imagery and Harris Geospatial’s ENVI program to produce a visual analysis of the growth trends of Spartina alterniflora on Poplar Island. Secondarily, biomass data from the scientists at Horn Point is being graphically displayed to discern patterns in growth or dieback, with the intention of comparing the biomass data to the imagery analysis.
Through knowing the patterns of growth and biomass, our GIS work is informing the scientists at Horn Point, the engineers from USACE, and other stakeholders on the effectiveness of this artificial wetland to provide habitat for all sorts of Chesapeake Bay organisms, reduce erosion, and be resilient to sea level rise- what a normal wetland ecosystem does.
What does the island look like now?Above: An aerial image of Poplar Island in 2017 from Google Earth.