Delaware is proud to be "The First State," the first to ratify the U.S. Constitution. It is also "the Blue Hen State," "the Diamond State" and "the Small Wonder" — the last a nod to its small land area. With low-lying land and coastal estuaries, it is also a state where change on the ground matters, and Landsat satellite imagery helps track it.
Tracking coastal change
Land sinking and sea level rising together have cost Delaware's low-lying land and coastal estuaries a great deal.
| Sea level rise at the Lewes tide gate since 1900 | More than 1 foot |
| Further rise projected by 2050 | 9–23 inches |
| Tourism | The state's fourth-largest employer; $3.5 billion to the economy in 2018 |
That rise threatens aquatic species, shorebirds and tourism, and coastal restoration and resilience are key pillars of the Delaware Climate Action Plan. Landsat imagery — now collected every 8 days and reaching back five decades — lets users map shoreline losses and land cover changes that squeeze coastal areas and affect drainage. It was the basis of one of the most widely cited studies of shoreline loss in Delaware Bay (Kearney and others, 2002), and it remains central to understanding the state's coasts.
The morning after a full-moon high-tide spawn, thousands of horseshoe crabs wait on the mud flats at Slaughter Beach for the tide to return. Photo: Conor McGowan, U.S. Geological Survey.
Watching over wetlands
Wetlands cover more than a quarter of Delaware, including 73,000 acres of tidal wetlands alone, and human activity and environmental factors have affected their health. Landsat gives more consistent, repeated coverage of wetland type, extent and flooding potential than other sources, so researchers studying coastal wetlands and their trends often rely on land cover data built from it — notably NOAA's Coastal Change Analysis Program, which uses Landsat as its main input and analyzes wetlands in detail every 5 years.
Documenting floods
Hurricanes and powerful storms are part of life in the Mid-Atlantic. About 22,000 Delawareans are at risk of flooding, and another 9,000 could be by 2050.
In 2021, Hurricane Ida brought Wilmington some of its worst flooding in decades. Landsat imagery lets first responders catalog flood damage across whole landscapes, see how fast floodwaters recede, and support recovery.
Ida's remnants dumped heavy rain on the Mid-Atlantic after its August 29, 2021, landfall in Louisiana, flooding roads and cutting power in Wilmington. Compared with a year earlier, the southern part of the right-hand image shows the flooding in lighter brown. Credit: U.S. Geological Survey.
Flooding and heavier rain also threaten agriculture, an $8 billion part of the state's economy. Landsat data can feed models of crop damage from storm surge and projections of landscape and coastal change that help authorities plan.
About Landsat
The USGS National Land Imaging Program supplies satellite imagery and other remotely sensed and geospatial data to government, commercial, academic and public users, with worldwide access to Landsat through the USGS Earth Resources Observation and Science (EROS) Center.
- Most-used. Landsat is the most widely used land remote sensing source in federal civilian agencies, and local, state and tribal agencies use it too, to monitor and forecast land surface changes.
- Everyday decisions. Its landscape-level view of land, inland lakes and coasts informs decisions on land, water and resources that protect life and property, safeguard the environment, advance science and education, and grow the economy.
- Business value. Companies use it for logistics, resource allocation and investment; commercial imaging firms build on it. A 2024 study put its total annual economic benefit at $25.6 billion, far more than it costs to build and run.
- Free and consistent. Long-term, accurate data at no cost lets users study broad areas and long-term trends, increasingly through cloud computing and analytics tools.
- What's next. Landsat 8 and 9 together image Earth's land every 8 days. NASA and the USGS are working toward the 2031 launch of Landsat 10, which is to extend the 50-plus-year record — the world's longest record of Earth's land surface.
Sources
Based on "Delaware and Landsat," U.S. Geological Survey Fact Sheet 2022–3064; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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