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NEW SATELLITE
MAPS PROVIDE PLANNERS IMPROVED URBAN SPRAWL INSIGHT
DC/Baltimore
Area in True Color - TIFF
Credit:
NASA/USGS
Click on pic
to enlarge
Here we see an
image of the Washington,DC/Baltimore area taken with the
Landsat satellite on March 27, 1998. For over 26 years, Landsat images have been
used to help urban planners understand where growth is taking
place and help geographers evaluate how different urban
planning programs effect population growth and land use.
Baltimore,
MD - TIFF
Washington, DC
- TIFF
Full view of
DC/Balt area - Click here for
TIFF Credit:
NASA/USGS/UMD-RESAC Click
on each image to enlarge This
is also Landsat data (from March and April of 1998) of the
Washington/Baltimore area, however a special algorithm has
been applied to it to illuminate the changes in low-density
residential land use which exemplify sprawl. There is a link
between impervious surfaces within a watershed, (here we see a
subset of the Chesapeake Bay watershed area) and the water
quality within the watershed. In general, once 10-15 % of an
area is covered by impervious surfaces, increased sediments
and chemical pollutants in runoff have a measurable effect on
water quality. When 15-25% of a watershed is paved or
impervious to drainage, increased runoff leads to reduced
oxygen levels and impaired stream life. When more then 25% of
surfaces are paved, many types of stream life die from the
concentrated runoff and sediments. Red represents high
concentrations of impervious surfaces. Blue represents
moderate concentrations and green represents low
concentrations of impervious surfaces. 
TIFF
TIFF
 TIFF Credit:
NASA/USGS/UMD/RESAC Click
on pics to enlarge This
map quantifies how much impervious surface there is across the
DC/Baltimore region. Baltimore City and the counties that
border it have at least 10% and up to 40% (indicated in
yellow, orange, and burnt orange colors) impervious surface area, indicating
that pollution from runoff is a problem. The District of
Columbia and surrounding watershed in Virginia and Maryland
have between 10-30% impervious surfaces (yellow and orange.)
Areas between and beyond Baltimore and DC are more green with
less than 10% impervious surfaces. Masking the areas (bottom
left and right) highlights the difference between the more
undeveloped areas versus the spread of urban areas.
For additional information
regarding this release, please contact:
Lynn Chandler
Lynn.Chandler.1@gsfc.nasa.gov
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/614-5562)
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