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Sustainable Communities and Lifestyles
The Impacts of U.S. “Urban Sprawl”
• What is it? “The Suburbs”• When did it begin and why? • How is the environment changed?• What are the consequences of “exurban
migration”?• Why Clustered Living and Development”?
Urban Sprawl
• Expansion of metropolitan areas (suburbs).• More houses, shopping centers and highways
farther from city centers.• Lack of overall land-use planning.• Facilitates extravagant consumption of resources.
– Energy– Materials
• Loss of “green-space” and farmland• Increased pollution (smog)
Factors That Contributed To Urban Sprawl - post-WWII
City overcrowding & pollutionFarmland sale and conversionCheap accessible mortgagesEasy car ownershipPost-war savings
Highway Trust Fund (1956)
Rate of Urbanization in Texas
0102030405060708090
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Decades
Per
cen
t U
rban
or
Ru
ral
0
5
10
15
20
Po
pu
lati
on
(M
illi
on
s)
% Urban% RuralTexas Pop.
Country Mouse to City Mouse
Environmental Impacts of Urban Sprawl
• Development on forests and grasslands =– Reduced water quality– Reduced air quality– Fewer renewable resources– Wildlife loss (biodiversity loss)
• Hydrologic Cycle Modification– Increased runoff, erosion, flooding– Reduced water quality and water table level
• Ecosystem simplification and destabilization
Wildlife Loss Mechanismsof Highways and Development
• Direct habitat destruction
• Habitat fragmentation– Territories too small– Migration interrupted
• Access to water prevented
• Highway fatalities (them not us)
Urban Wildlife Management Problems
• Changed societal attitudes towards animals
• Urban cougar, deer, and geese populations
Environmental Impacts of Urban Sprawl(Figure 24-6)
Indicators of Urban Blight/Decay• Economic and ethnic segregation• Eroding tax base• Loss of social services• Lowered property values• Higher property tax rates (improvements will result in more taxes)
• Deterioration of central city infrastructure• Decline in education quality• Loss of jobs and self esteem• More drug trafficking and violent crime
Consequence of Exurban Migration= Urban Blight/Decay!
What Makes Cities Livable?Why Clustered Living?
• Minimal commuting distance
• Reduced automobile traffic
• Improved access by foot or bicycle
• Improve mass transit
• Efficient central heating opportunities
• Heterogeneity of residences and businesses (cultural diversity)
• People meet people not cars
City Rehabilitation and Clustered Development
• Integrated living, working and recreational spaces (close proximity of shops, residences, services …)
• Affordable housing (smaller; town-homes)• Use alternative energy sources (e.g. solar).• Provisions for pedestrian and bicycle traffic.• Self-sufficiency in provision of food• Protection of sensitive habitats• Stable population