Urban Regions : Ecology and Planning Beyond the City

174Built systems, built areas, and whole regions

Number of major airports in urban region

Land cover subject to aircraft noise (%)

1 2 3 4 5 6 7

20

40

60

80

100

0

= Agriculture

= Built land

= Natural land

Figure 7.5Land-cover types subject to aircraft noise relative to number of major

airports. Percentage cover is the average for land extending approximately 5 km

(3 mi) out from both ends of major runways at major airports in the urban region.

The 5 km distance is based on Miller (2005).

closest one is rather distant, it is less convenient for travel to and from the

city and would tend to catalyze a connecting strip of development, serving as

abarrier to stream/river corridors and regional wildlife connectivity. However,

from air traffic and air pollution perspectives being further from the city is

good for a local/regional airport. Being distant is also good for a military airport

assuming that the many temporary personnel live nearby.

[S11]Most major airports are in cropland; a third of the regions have major airports

mainly in built areas, and 15 % mainly in natural land(Color Figures2--39).