One Map for Long Island Sound Watershed Data: The USGS Metadata Application

Long Island Sound is a tidal estuary in the northeastern United States. It covers 1,194 square miles, drains about 17,000 square miles, ranges from fresh water to salt water, and has almost 600 miles of shoreline. The Connecticut, Housatonic and Thames rivers and their tributaries make up most of its watershed, which reaches into Connecticut, Massachusetts, New Hampshire, New York, Rhode Island and Vermont, and into Quebec in Canada — home to nearly 9 million people.

Land use across the watershed ranges from urban areas along the Connecticut River and the Sound's coast to mostly forest and farmland in western Massachusetts, New Hampshire and Vermont. Because land use strongly affects stormwater runoff, groundwater recharge, flooding and ecosystem health, it matters to everything else in the watershed.

Land cover in the Long Island Sound watershed. U.S. Geological Survey.

Too many places to look

Federal, state, tribal, academic and community groups have studied the Sound and its watershed for years — water quality, nutrient loading, fisheries, plants and animals, groundwater, land use, infrastructure, climate change, sediment and geology, flooding, forestry and energy. Many states and organizations publish their data, but it is spread across separate databases, including:

• Connecticut's Department of Energy and Environmental Protection GIS Open Data site and Connecticut Environmental Conditions Online;
• MassGIS, the Massachusetts Bureau of Geographic Information;
• the New Hampshire Department of Environmental Services Geodata Portal;
• the New York State GIS Clearinghouse and New York City's Harbor Water Quality data;
• Rhode Island GIS and the Vermont Open Geodata Portal;
• the Water Quality Portal, USGS ScienceBase, and the Northeastern Regional Association of Coastal Ocean Observing Systems.

So the U.S. Geological Survey worked with the U.S. Environmental Protection Agency and the Long Island Sound Study to bring the information together in an interactive online map. Seeing projects across the watershed on one platform is meant to encourage collaboration, show where data are missing, avoid duplicated work and make better use of resources.

The Long Island Sound and Watershed Metadata map application. U.S. Geological Survey.

How it works

The application does not store data itself. It collects and displays metadata — information about the data — from public databases run by states and other organizations. As of August 2024 it held 707 data layers in 12 categories and 33 subcategories, including USGS and EPA Water Quality Portal records that can be filtered by site type, sample medium, characteristic group, state and date range.

Users can:

• change the base map from the sidebar;
• select layers, such as water-quality sampling, and filter them further;
• search layers by keyword and data type;
• check a legend showing the status of active layers;
• export the metadata for all active layers.

Filtering the Water Quality Portal layer; blue droplets mark Water Quality Portal records. U.S. Geological Survey.

In the field

USGS staff install a continuous water-quality monitoring gage on the Mystic River at Mystic Seaport, Connecticut. Photograph by Brittney Izbicki, U.S. Geological Survey.

The Moose River in Victory, Vermont, during a sampling trip. Photograph by Danny Hansen, U.S. Geological Survey.

The project was funded wholly or in part by the EPA through an interagency agreement with the USGS.

Sources

• U.S. Geological Survey: "The Long Island Sound and Watershed Metadata map application," Fact Sheet, citing the Long Island Sound Study (2024), Parker (2024), Latimer and others (2014) and Dewitz (2023).