Chesapeake Bay watershed to benefit from new Landsat 7 land cover maps

Contact: Lynn Chandler
lychand@pop900.gsfc.nasa.gov
301-614-5562
NASA/Goddard Space Flight Center–EOS Project Science Office

“Smarter” land use planning and better estimates of polluted water runoff across the 64,000 square-mile (110,000-square-kilometer) Chesapeake Bay watershed are on the horizon thanks to new land cover maps being produced by the Mid-Atlantic Regional Earth Science Applications Center (RESAC) at the University of Maryland. These maps, generated by overlaying images from NASA’s Landsat 7, will provide a more precise assessment of the presence and amount of different land cover types including residential development, wetlands, forests and crop lands.

The new maps and their application to environmental concerns in the Bay watershed will be discussed Tuesday, May 30, at the American Geophysical Union’s Spring Meeting in Washington, D.C. Scott Goetz and Stephen Prince of the university’s department of geography and the NASA-funded RESAC will report at the meeting on the center’s new products and on their map-generating system, which uses RESAC field data, classification software, and multiple Landsat 7 images taken during different seasons of a year.

“This type of precise land cover classification has not been done before for such an extensive region,” said Goetz, university research scientist and RESAC manager. “The new maps can distinguish low-density from high-density residential development and crop land from pasture land, as well as wetlands and different types of forest.”

Local and regional planning agencies in the Washington, D.C., area are currently working with the RESAC on the first Landsat 7 maps, which are centered on the nation’s capital and the surrounding counties in Maryland and Virginia. The Maryland Department of Planning has said it will use the maps in the state’s new “smart growth” initiative, while the parks commission in Montgomery County, Md., plans to assess the extent of forests in its parks.

The new land cover classifications will also help improve estimates of polluted water runoff flowing into the Chesapeake Bay by precisely identifying pasture land and different types of crops. This will allow more accurate estimates of the total amount of crop land around the Bay and the acreage in various crops. Scientists calculate the total amount of nutrient pollution entering the Bay by measuring the acreage of a certain type of land cover and estimating the average water quality of runoff from that type of land. Heavily fertilized agricultural fields, for example, produce higher levels of nutrients in runoff than the same acreage of pasture land.

Additional contact:Lee Tune
University of Maryland
Phone: 301-405-4679

The Mid-Atlantic RESAC at Maryland is one of seven such regional centers created by NASA in February 1999. The Mid-Atlantic center provides improved land cover mapping and ecological modeling capabilities for a diverse consortium of partners in government, academia, industry, and community and environmental organizations. Instead of producing one general land cover set of classifications, the RESAC develops customized land cover products for these users from a database of remote-sensing observations. According to Goetz, maps of the entire Chesapeake Bay watershed — which require 16 different Landsat 7 scenes acquired up to 6 different times in a year — should be completed by early next year.

Other innovative products that the Mid-Atlantic RESAC is producing include maps of roads, parking lots and other impervious surfaces using new high-resolution satellite imagery and improved features of the Landsat 7 instrument. Mapping the extent of these surfaces can be used to estimate damage to stream banks from storm runoff. This application and other high-resolution Landsat 7 mapping projects will be discussed at the AGU meeting by Prince, a professor of geography at the university and director of the RESAC.

News media can register for the AGU meeting by contacting Harvey Leifert, American Geophysical Union (tel. 202-777-7507; hleifert@agu.org)
Starting May 30 call the AGU Press Room at the Washington Convention Center (tel. 202-371-5087).

* Scott J. Goetz: “Land Cover Mapping of the Chesapeake Bay Watershed Using Landsat 7 and Ancillary Data” (H21A-06), May 30 at 11:15 a.m.

* Stephen D. Prince: “Impervious Surface Mapping Using High Spatial and Hyperspectral Resolution Imagery: A Case Study in Maryland” (H21A-07), May 30 at 11:30 a.m.