L ECTURE 16: Urban growth models Course Instructor: Md Asif Rahman (ASR) Lecturer, Department of Mathematics and Natural Sciences (MNS) University Building 2 (15 th Floor)

Urban growth model Concentric Zone Model: Burgess Sector Model: Hoyt Multiple Nuclei Model: Harris and Ulman

The Burgess Urban Land Use Model In 1925, Burgess presented a descriptive urban land use model, which divided cities in a set of concentric circles expanding from the downtown to the suburbs. This representation was built from Burgess' observations of a number of American cities, notably Chicago, for which he provided empirical evidence. The model assumes a relationship between the socio- economic status (mainly income) of households and the distance from the CBD.

The idea behind this model is that the city grows outward from a central area in a series of rings. The size of the rings may vary, but the order always remains the same. This model suggests that the social structure extends outwards from the central business district. Also, as you get further away from the city density decreases.

An important feature of this model is the positive correlation of socio-economic status of households with distance from the CBD Burgess described the changing spatial patterns of residential areas as a process of "invasion" and "succession". As the city grew and developed over time, the CBD would exert pressure on the zone immediately surrounding it (the zone of transition). As the city grows each zone will expand to its nearest one and most affluent (rich) residents will move further from CBD.

CBD Industry/factory Zone of transition & poorest residents Residential Zone (Working class/ middle class) Higher middle or higher Class Residents High Class Sub- urban/rural housing

Zone I: Central Business District (CBD) where most of the tertiary employment is located and where the urban transport infrastructure is converging, making this zone the most accessible. Zone II: Immediately adjacent to the CBD a zone where many industrial activities locate to take advantage of nearby labor and markets. Further, most transport terminals, namely port sites and railyards, are located adjacent to the central area. Zone III: This zone is gradually been reconverted to other uses by expanding manufacturing / industrial activities. It contains the poorest segment of the urban population, notably first generation immigrants living, in the lowest housing conditions.

Zone IV: Residential zone dominated by the working class and those who were able to move away from the previous zone (often second generation immigrants). This zone has the advantage of being located near the major zones of employment (I and II) and thus represents a low cost location for the working class. Zone V: Represents higher quality housing linked with longer commuting costs. Zone VI: Mainly high class and expensive housing in a rural, suburbanized, setting. The commuting costs are the highest. Prior to mass diffusion of the automobile (1930s), most of these settlements were located next to rail stations.

According to Burgess, urban growth is a process of expansion and reconversion of land uses, with a tendency of each inner zone to expand in the outer zone.

Although the Burgess model is simple and elegant, it has drawn numerous criticisms: The model is too simple and limited in historical and cultural applications up to the 1950s. It is a product of its time. The model was developed when American cities were growing very fast in demographic terms and when motorized transportation was still uncommon as most people used public transit. Expansion thus involved reconversion of existing land uses. This concept cannot be applied in a contemporary (from the second half to the 20th century) context where highways have enabled urban development to escape the reconversion process and to take place directly in the suburbs.

The model was developed for American cities and has limited applicability elsewhere. It has been demonstrated that pre-industrial cities, notably in Europe, did not at all followed the concentric circles model. For instance, in most pre-industrial European cities, the center was much more important than the periphery, notably in terms of social status. The Burgess concentric model is consequently partially inverted. There were a lot of spatial differences in terms of ethnic, social and occupational status, while there were low occurrence of the functional differences in land use patterns. The concentric model assumed a spatial separation of place of work and place of residence, which was not generalized until the twentieth century.

Sector Model/Wedge model American Land economist Homer Hoyt introduced sector model in it is an improvement upon the concentric zone model as it incorporates distance and direction. The Theory: Hoyt stated that growth or expansion of a city occurs along a particular transportation route which gives the city a shape of an octopus. He collected data of 64 American cities which are mostly small and medium in size.

According to him increase in population is the main reason behind any city’s development and change. Increase in population creates pressure on land and they changes land use. Hoyt mentioned five distinctive sectors of urban land use. 1. CBD 2. Wholesale and light manufacturing 3. Low class residential area 4. Middle class residential area 5. High class residential area

Hoyt – His idea. 1. CBD (A) 2. Wholesale and light manufacturing(B1) 3. Low class residential area (B2) 4. Middle class residential area (C) 5. High class residential area (D)

A –The Central Business District (CBD)  This area contains shops, offices, banks, etc.  Land is expensive, and this area has high rents and multi story buildings as a consequence.  There is very little space and competition is high.  Congestion levels are high.  Vegetated areas are sparse.

B1- Wholesale and light manufacturing Industries grow up beside the main road, rail station, or near the rivers. Keeping link with the CBD, wholesale areas will grow up in one or both side of the Central business District.

B2- Low class residential housing Low rent residential areas are located beside industrial areas and these areas are found in such a place which is far from high class residential areas.

C- Middle class residential Semi-detached housing is found here with no gardens. These houses are built on large estates. Less expensive private estates can also be found here. Often described as ‘medium class residential’ or ‘inter-war’ areas.

D- High Class Residential This is a high class residential area where private, quality housing can be found. Detached and semi-detached housing can be built on cheaper land. Often lots of garages, big gardens, and many out buildings can be found here. Most people commute to work from this zone as it is furthest away from the centre.

E- Countryside Areas In the countryside surrounding the urban area, those seeking to escape from the urban area can live in pleasant surroundings. However, they are still close to work. Many satellite villages and towns surround major urban areas allowing people to live further away from the main settlement.

Filtering Process  Hoyt mentioned filtering process for changing the urban areas. According to him, working capability, skillness, luxury, ambition on human being increases day by day and thus a city expands.  The higher class move to the periphery for attractive pull factors. The middle class take up the vacant land left by higher class.. In this way, lower class move to the vacant land of middle class. This is called Hoyt’s filtering Process.

 Criticism:  1. According to Firey, Hoyt had not sufficiently considered the role of cultural and social systems in conditioning landuse.  2. He also questioned the validity of comparing the results of work in a number of cities when relief, location of a waterfront, and other factors effects the sector pattern of some cities so markedly.  3. Firey carried out a landuse study of Central boston, which he claimed, seemed to contradict various aspects of Hoyt’s Theory  4. Hoyt mentioned about only one CBD but now a city has more than one CBD

5. He only mentioned about development of roads for urban growth 6. He emphasized more on High class residential area 7. He gave less importance on industrialization for the development of urban structure 8. This model needs a vast plain land area which is not possible in real world 9. His theory is based on USA which is not suitable for third world countries 10. This is based on 64 cities so tough to test.

Multiple nuclei model A model of town growth by C. D. Harris and E. L. Ullman in 1945 Distinctive land-use zones develop because some activities repel each other high-quality housing does not generally arise next to industrial areas other activities cannot afford the high costs of the most desirable locations. New industrial areas develop in suburban locations since they require easy access outlying business districts may develop for the same reason. Transportation improvements allowed for deconcentration