Chapter 14Section 2: Urban Land Use

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.

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)

Metropolitan Areas

• Small towns that have grown together to form larger urban areas.

• Examples:• Denver-Boulder• Boston-Worchester-Lawrence• Washington, D.C.-Baltimore

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

When Urban Areas Grow Too Fast…

• It can overwhelm the infrastructure and lead to traffic jams, substandard housing, and polluted air and water.

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

When more people live in

a city than its

infrastructure

can support…

Urban Crisis

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.

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.

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.

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.

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

Heat Island

• The increased temperature in the city.

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.

Moderating Heat Islands

• Planting trees for shade

• Installing rooftops that reflect rather than retain heat.

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.

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.

Intelligent Design• Land-use planners use a Geographical Information

System to store, manipulate, and view geographic data.• Location of sewer lines, roads, parks, etc.

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.

Manhattan vs. Florence

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.

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.

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.