Sustainable Urban Development: Challenges and Solutions

1. Chapter 14 Section 2: Urban Land Use

2. Urbanization • What it is: The movement of people from rural areas to cities. • Why it happens: People leave rural areas for more plentiful and better paying jobs in towns and cities.

3. Urbanization in Developed Countries • Slowed in second half of 20th century. • 1960: 70% of U.S. population was classified as URBAN. • 1980: 75% classified as URBAN. (only slight increase)

4. Metropolitan Areas • Small towns that have grown together to form larger urban areas. • Examples: • Denver-Boulder • Boston-Worchester-Lawrence • Washington, D.C.-Baltimore

5. When Urban Areas Grow Slowly… • They can be pleasant places to live. • Roads and public transportation have been built to handle growth. (traffic flows freely) • Buildings, roads, parking lots are mixed with green spaces. • Green spaces provide much-needed ecosystem services: • Moderation of temperature • Infiltration of rainwater runoff • Aesthetic value

6. When Urban Areas Grow Too Fast… • It can overwhelm the infrastructure and lead to traffic jams, substandard housing, and polluted air and water.

7. Infrastructure • All of the things that a society builds for public use. • Infrastructure includes: • Roads • Sewers • Railroads • Bridges • Canals • Fire and police stations • Schools • Libraries • Hospitals • Water Mains • Power Lines

8. When more people live in a city than its infrastructure can support… Urban Crisis

9. Urban Sprawl • Rapid expansion of city into the countryside around the city. • Results in building of suburbs or housing and associated commercial buildings on the boundary of a larger town.

10. Suburbs (spread over another 2.5 million acres per year.) • Many are built on land that was previously used for food production • 2000: more Americans lived in suburbs than cities and countryside combined.

11. Development on Marginal Lands • Many cities were first built where there was little room for expansion. • As cities grew, suburbs were often built on marginal land.

12. Marginal Lands • Land that is poorly suited for building. • Examples: Los Angeles and Mexico city • Built on basins • Cities have expanded into mountains • Slopes are prone to landslides • Difficult and expensive to repair damaged buildings.

14. Other Impacts of Urbanization • Cities generate and trap more heat. • Heat generated by infrastructure that makes city run. • Roads and buildings absorb more heat than vegetation. • Heat is retained longer in cities. • Result of more heat: Heat Island

15. Heat Island • The increased temperature in the city.

16. Heat Islands Affect Weather • Scientists are beginning to see that heat islands can affect local weather patterns. • Hot air rises over a city, cooling as it rises, and eventually produces rain clouds. • Side effect: increased rainfall.

17. Moderating Heat Islands • Planting trees for shade • Installing rooftops that reflect rather than retain heat.

18. Urban Planning • Land-use Planning: determining in advance how land will be used • Where houses, businesses and factories will be built • Where land will be protected for recreation • Best locations for shopping malls, sewers, electrical lines, and other infrastructure.

19. Making Land Use Models • Complex • Controversial • Requires developers to prepare detailed reports assessing environmental impacts. • Public has right to comment on reports. • Can be disagreed upon by developers, city governments, and local businesses.

20. Intelligent Design • Land-use planners use a Geographical Information System to store, manipulate, and view geographic data. • Location of sewer lines, roads, parks, etc.

21. Transportation • Most cities are difficult to travel in without a car. • Most American cities: • Built after invention of automobile. • Cover large areas • Most European cities: • Built before invention of automobile. • Narrow roads and more compact.

22. Manhattan vs. Florence

23. Mass Transit • Use buses and trains to move many people at one time. • Save energy • Reduce highway congestion • Reduce air pollution • Limit loss of land to roadways and parking lots.

24. Open Space • Land within urban areas that is set aside for scenic and recreational enjoyment. • Parks, public gardens, bicycle and hiking trails. • Often called GREENBELTS. • Greenbelts provide important ecological services.

25. Benefits of Open Spaces • Absorb carbon dioxide. • Produce oxygen. • Filter out pollutants from air and water. • Keep cities cooler. • Absorb rainwater and runoff. • Spaces for exercise and relaxation.