2001 EARTH SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| PAVEMENT AND THE CHESAPEAKE BAY: HOW URBAN SPRAWL AFFECTS OUR WATER | G01-043 | 05/30/01 | 00:08:27 | The way land is used and altered impacts more than just the land itself, it also impacts the water bodies- the streams, rivers and bays- around which we live.
A major advance in satellite-based land surface mapping has led to the creation of detailed maps of urban-built environments and their impervious surfaces (surfaces incapable of being penetrated, i.e. pavement.) These maps provide urban planners with a better understanding of how sprawl advances and how runoff from rainfall over paved surfaces affects regional water quality.
Ultimately, the more that an area is covered with impervious surfaces, the higher the degradation of water quality, as more sediment and chemical pollutants are added to the watershed. According to researchers, the percentage of impervious cover in a watershed is directly related to the physical and chemical properties of surface water bodies and has been linked to the amount of suitable habitat available for aquatic life.
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TAPE CONTENTS: |
| ITEM (1): Landsat Views Baltimore and Washington - 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.
Courtesy: NASA/USGS
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| ITEM (2): Impervious Surface Area of the Washington/Baltimore Area -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.
Courtesy: NASA/USGS/UMD/ RESAC
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| ITEM (3): Chart of Washington DC/Baltimore Watershed Areas - 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 highlights the difference between the spread of urban areas versus the more undeveloped areas.
Courtesy: UMD/RESAC/NASA/USGS
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| ITEM (4): Urban Growth in Washington, DC - These images show the progression of urban growth in the DC area from 1973 to 1996. Urban sprawl results in more paved surfaces and less area for water to drain into soils. Reduced drainage areas then bring more water into drainage systems at a faster rate, eroding stream and rivers and reducing water quality because more sediments are mixed into the water. According to researchers, if you increase an impervious surface near a stream by creating a paved parking lot, for example, you directly affect the quality of life in the stream because of the runoff that surface will generate. Courtesy: NASA/USGS
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| ITEM (5): Baltimore-Washington Corridor - This Landsat image depicts the Washington, DC -Baltimore corridor. Zooming in first to Washington, past the beltway and up I-95 to Baltimore, this image shows the narrowing gap between the two urban centers. Courtesy: NASA/USGS
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| ITEM (6): SeaWiFS Chesapeake Bay Flyover - Another view of the entire Chesapeake Bay region, taken using the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument. SeaWiFS observes the world's oceans, measures the ocean "color" (by monitoring the growth of marine plant life) and helps to provide information for coastal zone management. This series of four true color images was taken on: April 12, 1998, May 15, 1998, October 4, 1997 and December 16, 1997 Courtesy: NASA/ORBIMAGE
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| ITEM (7): Shuttle Views of the Chesapeake Bay - This view of the Chesapeake Bay was taken from the Space Shuttle during the STS-40 mission in June of 1991.
Courtesy: NASA
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| ITEM (8): Landsat Satellite - The Landsat satellite is part of NASA's Earth Science Enterprise program- a long term research effort to monitor, study and map the Earth. Landsat data is used in multiple applications, including the study of urban growth. Courtesy: NASA
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| ITEM (9): SeaWiFS Instrument - The SeaWiFS Mission is also a part of NASA's Earth Science Enterprise.
Courtesy: NASA
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Earth Science Gallery