The multiple nuclei model is a theory of urban development that suggests that cities grow and develop around multiple centers, or “nuclei.”
It improves upon the concentric zone model proposed by Ernest Burgess in 1925. This latter model conceived of cities as expanding outwards from a central business district in concentric circles.
The multiple nuclei model was proposed by C.D. Harris (1914 – 2003) and E.L. Ullman (1912 – 1976), geographers at the University of Chicago in 1945.
Examples of cities with a multiple nuclei model include Houston, Delhi, Chicago, London, and Sydney.
Multiple Nuclei Model vs Concentric Zone Model
Whereas the concentric zone model envisages cities with one central business district (CBD), the multiple nuclei envisages cities with several CBDs serving different industry needs.
A prominent drawback of the concentric zone model was that it could not explain situations where cities, with time, had developed multiple central business districts, and thus had multiple concentric zones of commercial and residential areas emanating outwards from each.
The multiple nuclei model improves upon the concentric zone model by proposing that cities need not have a single central business district (CBD), but instead can be composed of multiple commercial centers or multiple nuclei around which commercial and residential zones emerge.
The reason that such multiple nuclei develop is that different kinds of commercial and industrial activities have different spatial and environmental needs.
For instance, export or import-dependent industries need to be located close to airports or seaports.
When the concentric zone model was first proposed in 1925, commercial air travel was in its infancy, and most major cities in the world did not yet have airports. CBDs were typically located either around seaports, or the inland transportation hubs around which the city was originally founded.
Within a few decades, however, airports became important landmarks in most major cities in the world. Around airports cropped up commercial ecosystems comprising industries that relied on air cargo, hotels that served frequent air travelers, and residential units that served the workers who found employment in all these air travel-related commercial establishments.
So now most large cities have at least two CBDs.
With the development of other, newer forms of commerce and industry in the 20th century such as software and technology, films and entertainment, etc., that were little known in 1925 when Ernest Burgess first formulated the concentric zone model, most major cities evolved to have several CBDs, and thus multiple nuclei.
Read Also: Urban Realms Model vs Multiple Nuclei Model
Multiple Nuclei Model Examples
1. Houston, Texas
Houston was founded in the mid-19th century as a storage and transportation hub for cotton that was produced in Texas’ vast cotton plantations.
The earliest commercial and residential hubs were thus situated around the cotton storage and transportation areas.
In the late 19th century, the discovery of oil in Texas led to the oil and gas industry becoming a major driver of Houston’s economy. Not just drilling of oil but manufacturing of oilfield equipment and petrochemical products became major industries in Houston. This led to the development of a new “nucleus” around which the city expanded in concentric zones.
In the late 20th century, the services sector, in particular, medical care became a major contributor to the city’s growth.
The Texas Medical Centre located in southern Houston is home to over 60 hospitals, medical research institutes, and nursing and paramedical centers, making it the largest medical complex in the world (Sachs, 2011). It employs over 1,00,000 people and receives over 10 million patients a year. More than 20,000 people are residents in the area, most of them employees of the medical complex.
Thus a third nucleus, distinct from the cotton and oil and gas centers emerged in the late 20th century.
In the 21st century, several major software and technology firms such as Hewlett-Packard (HP) have announced shifting their headquarters to Houston, as part of a larger migration of tech firms from California to Texas. (Folger, 2021) This is leading to the emergence of yet another nucleus.
At the same time, the other nuclei, serving older industries continue to remain relevant to the city’s economy. Cotton and oil continue to be important to the economy of Texas and Houston even as technology and medicine play key roles in creating new jobs and driving growth. Thus Houston has at least 4 different nuclei each with a different functional specialization.
2. Delhi, India
Delhi has been a major world city at least since the 10th century CE, serving as the capital of successive large empires that arose in South Asia through the ages. As a result, the city developed around multiple nuclei, each associated with the administrative and commercial proclivities of the empire or state that ruled it.
For instance, the Mughal Empire, which ruled over most of South Asia from the 16th to the 18th centuries had its capital in the walled city of Delhi, also known as Old Delhi.
This part of the city is characterized by narrow, winding lanes, crowded bazaars packed with hawkers selling wares, roadside stalls heaped with spices and savories, and imposing medieval mosques, minarets, and mausoleums made of marble and red sandstone.
By contrast, the British Empire that replaced the Mughal chose as its capital a site a few kilometers south of the Mughal Old Delhi, which came to be known as New Delhi.
The British built here grand new structures in the Victorian and Edwardian styles that became living testimonies to the grandeur and opulence of the British Raj upon which the sun was never said to set. In the first half of the 20th century, British New Delhi replaced Mughal Old Delhi as the new nucleus around which the city’s commercial and residential growth revolved.
With the end of the British Raj and the partition of India, the influx of refugees from what became Pakistan was accommodated on wastelands a few kilometers further to the south of British New Delhi.
With time, the partition refugees prospered, building imposing neo-colonial bungalows, kitschy nouveau-riche McMansions, and trendy marketplaces modeled on Parisian sidewalks and Italian squares.
Towards the end of the 20th century, this region known as South Delhi emerged as the economical and cultural heart of Delhi and the latest in its series of multiple nuclei.
With the beginning of India’s IT boom at the start of the 21st century, a new nucleus emerged even further to the south in a suburb of Delhi known as Gurgaon (now renamed Gurugram). It soon became the chosen base of some of the biggest multinational corporations on earth from which they ran their operations in Asia. Almost every global corporation worth its name, from the Boston Consulting Group to British Petroleum to Bank of America has its office in one of the several steel and glass skyscrapers of Gurgaon.
All these multiple nuclei, though separated by more than 5 centuries of history, coexist within the modern city of Delhi.
The multiple nuclei model was originally devised to explain the development of Chicago towards the middle of the 20th century.
At the time of its foundation in the early 19th century, economic activity in Chicago centered around the Chicago Portage – a water transportation system connecting the Great Lakes waterways to the Mississippi River, thus providing easy access from the North Atlantic Ocean to the Rocky Mountains in the American mid-west and all the way down to the Gulf of Mexico where the Mississippi river drained.
As a result, the earliest central business districts (CBD) of Chicago emerged around the transportation and waterways industries.
With time, however, other industries such as manufacturing, finance, aerospace, and education flourished leading to the development of several different nuclei in different parts of the city.
The University of Chicago for instance, is one of the leading universities in the world, with over 94 Nobel Laureates being associated with it at some point in their careers.
The university is located in the Hyde Park neighborhood of Chicago which also hosts a number of other educational institutes, coming to be renowned as a higher education hub that attracts the best research talent from all over the world.
This makes Hyde Park just one of the several nuclei around which the city of Chicago continues to develop.
London also has multiple nuclei which act as the commercial, administrative, and political nerve centers of the city.
The City of London or simply “ The City”, is a commercial and financial hub in London that is home to the Bank of England. Also called “the square mile” because it is spread over an area of 1.12 square miles, “The City” houses the headquarters of some of the largest firms in the world including Standard Chartered Bank and Unilever.
2.5 miles to the east of “The City” lies the second commercial nerve center of London known as Canary Wharf which houses some of the tallest skyscrapers in London, including the 50-storeyed One Canada Square, once the tallest skyscraper in the UK.
A third nucleus in London is Westminster, the seat of the British Parliament and home to the Buckingham Palace, the residence of the Queen of England. Westminster thus is the center of political and administrative power in London.
5. Lagos, Nigeria
Lagos is the largest city in Nigeria and the second-most populous city in Africa.
It is one of the busiest seaports in Africa, home to the largest film and entertainment industry in Africa, and central to the oil industry of Nigeria, Nigeria being one of the largest exporters of oil in the world. In addition, Lagos is also the information and communication technology (ICT) hub of West Africa.
Due to the presence of these large and varied industries, land use patterns in Lagos follow the multiple nuclei model as different economic and commercial hubs emerge in different parts of the city (Olayiwola, et. al., 2005).
The Central Business District (CBDs) of Lagos is located in the heart of Lagos Island covering colonial-era commercial streets such as Church Street, Broad Street, and Balogun Street. However, several other CBDs have come up in Lagos to cater to the needs of the fast-expanding megapolis. There is a CBD in the Lekki Special Economic Zone (SEZ), a suburb of Lagos, and another one in Ikeja, 17 kilometers from Lagos.
Strengths of the Multiple Nuclei Model
- Explains Multiple Central Business Districts Within a Single City – An obvious advantage the multiple nuclei model has over its predecessors is the ability to explain the existence of multiple CBDs. This, in fact, was the raison d’etre of the model.
- Explains the Development of Suburbs and Satellite Towns – Unlike the concentric zone model, the multiple nuclei model does a convincing job of explaining the development of suburbs and satellite towns that emerge on the outskirts of the main urban center and with time mature into as self-contained urban centers in their own right.
- Makes More Practical Assumptions – One of the central assumptions of the concentric zone model was that the land available for the expansion of a city is flat and limitless. The multiple nuclei model on the other hand begins with the assumption that the land is not flat and that limitations of the terrain will affect how residents make use of the land. This renders it more practical for real-life scenarios.
Weaknesses of the Multiple Nuclei Model
- Fails to Explain the Development of Slums and Informal Settlements – Slums, squatter colonies, and informal settlements have become an inalienable part of most major cities in the world. These are especially a prominent part of the urban landscape in Asia, Africa, and Latin America. The multiple nuclei model does not provide any explanation for why slums appear, or where they lie on the spatial division of the urban landscape as defined by it.
The multiple nuclei model is a vast improvement over its predecessor, the concentric zone model. It does a better job of explaining the observed patterns of land use in cities, and makes more practical assumptions. However, it fails to explain the development of slums and informal settlements, which are a major part of most urban landscapes.
Real-life cities that seem to conform to the multiple nuclei model include London, New York City, and Lagos. These cities all have multiple CBDs that serve differing industries and purposes.
Folger, J. (September 2021) Why Silicon Valley companies are moving to Texas Investopedia https://www.investopedia.com/why-silicon-valley-companies-are-moving-to-texas-5092782.
Olayiwola, L.M., Adeleye, O.A. & Oduwaye, A.O. (2005) Correlates of land value determinants in Lagos Metropolis, Nigeria, Journal of Human Ecology, 17(3), 183-189, DOI: 10.1080/09709274.2005.11905778
Sachs, L. (May 2011) The world’s largest medical center is now among the most energy efficient Energy.gov https://www.energy.gov/articles/world-s-largest-medical-center-now-among-most-energy-efficient