Urbanization and Urban Models - Lecture Notes

Urbanization in Sub-Saharan Africa

• Urbanization Rates: Account for 40% of global urban growth.

Megacities in Africa

• The phenomenon of Megacities highlights the rapid urbanization trends across the continent.

Objectives of Urban Patterns Lectures

• Understanding the clustering of services downtown.
• Comprehending the distribution of residents within urban areas.
• Identifying reasons for urban area expansion.
• Analyzing challenges faced by cities.

Key Questions for Discussion

• Services: Origins and triggers for urbanization.
• The relevance of Central Place Theory and Gravity Model in service distribution.
• The difficulty of defining urban areas and their demographics in different contexts (MDC vs LDC).
• The impact of primate cities on service distribution and the tendency for service clustering in downtown areas.

Characteristics of Central Business Districts (CBD)

• Description: CBDs are characterized by a low percentage of urban land area yet a high concentration of urban services.
• Types of Services in CBDs:
  1. Public Services: City administration, courts, libraries, and sports/convention centers.
  2. Business Services: Advertising, banking, finance, and legal services that thrive on proximity to other businesses.
  3. Consumer Services: Retailers with high thresholds, ranges, or those serving CBD workers. Trends show a decline in retail due to shifts to affluent suburbs.
• 3-Dimensional Nature of CBD: Vertical development is necessary due to land demand, creating underground spaces for utilities and high-rise buildings.
• Bid-Rent Theory: Explains how land pricing changes with distance from the CBD, indicating the economic advantage of central locations.

Urban Area Definitions

1. City: An incorporated urban settlement that serves as a governing unit (e.g., central city in the U.S.).
2. Urban Area: Encompasses densely settled cores, suburbs, and linked low-density areas. Defined by the census as either urbanized (50,000+) or clusters (2,500-50,000).
3. Metropolitan Statistical Area (MSA): Includes urbanized areas, its county, and surrounding areas with economic ties, primarily work-related.
4. Micropolitan Statistical Area: Defined similarly but includes areas with a population of 10,000 to 50,000.

Urban Expansion Insights

• Core-Based Statistical Areas: These encompass various urban areas, illustrating growth patterns in metropolitan and micropolitan contexts.
• Urban Sprawl: Characterized by unplanned chaotic growth around the edges of urban areas, leading to inner-ring suburbs formed before the 1970s and outer-ring suburbs developing later for larger, cheaper plots.
• Boomburbs: Rapidly expanding suburban cities housing over 100,000 residents, often indicative of economic growth.

Urban Growth Drivers

• Major factors for urban expansion include legislation like the Interstate Highway Act, social mobility, and housing policies like the GI Bill post-WW2.

Urban Models and Distribution

• Concentric Zone Model: Proposed by E.W. Burgess in 1923, which posits that urban growth occurs in rings.
  • Zones include a CBD, transition areas, working-class homes, middle-class residences, and commuter zones.
• Sector Model: Coined by Homer Hoyt, suggesting urban areas develop along zones radiating from the CBD based on socio-economic status.
• Multiple Nuclei Model: Developed by Harris and Ullman, depicting urban areas as having multiple centers of activity, reflecting the complexity of modern urban growth.

Urban Challenges

• Social Stratification: Issues like gentrification, permanent underclass, and urban decay due to poor urban planning and the unavailability of affordable housing.
• Economic Disparity: Inner-city residents often face higher unemployment, substandard housing, and are disproportionately affected during economic recessions.

The Future of Urban Areas

• Predicted growth in megacities in developing regions is coupled with challenges such as dualism and rapid urbanization without adequate infrastructure.
• Urban models will help articulate urban dynamics and the impact of sustainable practices to tackle future urban challenges.

Sustainable Urban Development Concepts

• Smart Growth: Strategies focused on compact urban growth; cities like Portland exemplify this through urban growth boundaries and infill strategies.
• New Urbanism: Advocates for walkable, mixed-use communities to enhance quality of life and reduce dependence on automobiles.
• The role of public transportation is emphasized in reducing congestion in urban areas, crucial for sustainability and environmental consideration.