Hydrography data more than doubles the number of previously-mapped stream channel miles

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Annapolis, MD—The Chesapeake Bay Program is pleased to announce an update to its High-Resolution Land Use/Land Cover Data and Change Data and, for the first time, Hyper-Resolution Hydrography Data that precisely identify the location, dimensions and connectivity of streams, ditches and other waterways.

Land Use and Land Cover Data and Change Data

The updated High-Resolution Land Use/Land Cover Data and Change Data, now available for 2013/2014, 2017/2018 and 2021/2022, provide a detailed understanding of how the land of the Bay watershed is being managed and how it’s changed over time, which is critical for Bay restoration.

The updated Land Use/Land Cover Data provides an innovative 1-meter resolution characterization of the watershed and its land types, enabling decision makers to more precisely target their strategies for Bay restoration.  The data include 56 detailed land-use classes, such as forest, cropland and roads, across 99,000 square miles with 95% accuracy. Available to everyone, including county and state planners and conservation groups, these data can be widely used to address complex land management challenges, community planning, conservation efforts, human safety planning around flooding and environmental restoration efforts across the Chesapeake Bay watershed.

The updated 1-meter resolution Land Use/Land Cover Change Data tracks patterns of development, resource extraction, agriculture and natural landscape change over the same 2013/2014, 2017/2018 and 2021/2022 time periods. Overall, these data capture 96% of land use change with 77% accuracy. These data offer crucial insights into the patterns of development, habitat change and environmental effects which, in turn, inform evidence-based strategies and policies for accommodating economic and population growth while restoring and maintaining the health of the Chesapeake Bay. Later this summer, once the evaluation of the land change data is finalized, the Bay Program will provide an update of the changes to the amount of tree canopy, forest cover and impervious surface in the watershed.

“High-resolution land use and land cover data and hyper-resolution hydrography data are foundational, authoritative and game changing to environmental restoration and conservation,” said Peter Claggett, research geographer with the U.S. Geological Survey and lead, Chesapeake Bay Program Land Data Team. “The data are foundational to a wide variety of environmental assessments and geographic analyses because they describe the human-modified and natural landscape and how both have changed over time. The data are authoritative because they are both accurate and transparent with easily recognizable features such as roads, structures and tree canopy.  Most importantly, the data are game changing, enabling the identification of restoration and conservation opportunities throughout the Chesapeake Bay watershed at local scales down to individual farms, forest tracts and developments.”  

Partners working on both the Land Use/Land Cover Data and Change Data include the Chesapeake Conservancy, U.S. Geological Survey, University of Vermont Spatial Analysis Lab and U.S. Environmental Protection Agency.

Hyper-Resolution Hydrography Data

The High-Resolution Land Use/Land Cover Data and Change Data, as well as the Hyper-Resolution Hydrography Data, are used to track progress toward multiple goals and outcomes in the Chesapeake Bay Watershed Agreement and inform Chesapeake Bay Total Maximum Daily Load planning efforts that will help watershed jurisdictions make progress toward meeting their pollutant reduction goals. No where else in the country has data covering such a large area of this quality and spatial, temporal and categorical  resolution. All three datasets are open source and provided free for anyone. Both the High-Resolution Land Use/Land Cover Data and Change Data and Hyper-Resolution Hydrography Data can be accessed on the U.S. Geological Survey ScienceBase-Catalog.

"Maps such as these do more than show locations, they are tools for a host of societally-relevant applications and a record of environmental conditions in time,” said Matthew Baker, Ph.D., professor of geography & environmental systems at the University of Maryland, Baltimore County. “The good news is that the time increment between the dusty old and the shiny new maps is shrinking. The Bay Program is supporting new ways of accelerating this process to the point where such maps can be used to help monitor the dynamics of landscape change as well as its status. What's exciting is that the new mapping procedures are not just making mapping easier, they are also providing useful new measurements, leading to further discovery and expanding our understanding of both the natural and built environment." The new Hyper-Resolution Hydrography Data more than doubles the number of mapped stream channel miles compared to existing national data, making them the most comprehensive inventory of the watershed’s stream and ditch network to date. The data precisely locate stream channels, include attributes of channel dimensions, and are 94% accurate for streams represented by existing national data, and between 67–82% accurate for previously unmapped streams with accuracy rates increasing for larger streams. This detailed, accurate accounting of the stream network provides insights into how the land is connected to the conditions of streams and the Bay. A variety of environmental challenges that state and local governments face are informed by these data, including flood control, fish passage, stream restoration, pollutant transport and other water resource and aquatic habitat concerns.

“We now have tools to drive the most efficient and effective conservation of the Chesapeake Bay watershed yet,” said Michael Evans, Ph.D., deputy director and lead data scientist at the Chesapeake Conservancy’s Conservation Innovation Center. “The new hyper-resolution hydrography data will transform how the Chesapeake Bay is managed and restored. This innovative approach to stream mapping reveals more than twice as many stream miles than were previously mapped. Most of these are small headwaters—the capillaries that play an outsized role in linking what happens on the land to conditions in the Bay. Combined with the detailed understanding of land use dynamics that three time periods of high-resolution land cover data provide, decision makers can evaluate policies, forecast future scenarios and take actions to improve water quality with unprecedented precision."

Partners working on this dataset include University of Maryland, Baltimore County, U.S. Geological Survey and Chesapeake Conservancy.

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