👪 Population growth
More people, from migration and natural increase, need somewhere to live. When the centre is full, new homes are built at the edge.
Opportunities and Challenges of Urbanisation » Urban Sprawl and the Rural-Urban Fringe
What you'll learn this session
Study time: 30 minutes
Cambridge spec: 7.2.3
- What urban sprawl and the rural-urban fringe are
- Why cities spread outwards: housing, cars, cheaper land and out-of-town developments
- The positive and negative impacts of sprawl on the fringe and the countryside around it
- Green belts and brownfield sites as responses, introduced briefly
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Unlock This CourseWhat is urban sprawl?
When a city grows, it does not only get busier. It also gets wider. New roads, houses, shops and factories creep outwards and cover land that used to be fields and woodland. This lesson looks at that spreading and what it does to the land around a city.
Key terms:
- Urban sprawl: the uncontrolled outward spread of a city's built-up area into the surrounding countryside.
- Rural-urban fringe: the zone at the edge of a city where built-up land meets the countryside. It is a mix of houses, farms, golf courses, warehouses and open land.
- Commuter: a person who travels regularly between where they live and where they work.
- Greenfield site: land that has never been built on, such as a farm field.
- Brownfield site: land that has been built on before and is now unused, such as an old factory or goods yard.
- Green belt: a ring of land around a city where building is strictly limited, to stop it sprawling.
Think of a drop of ink on blotting paper. The ink spreads outwards from the middle, and the edge is blurry rather than sharp. The blurry edge is the rural-urban fringe.
Why do cities sprawl?
🏡 Demand for housing
People want bigger homes with gardens, and more people now live alone. Both mean more houses are needed, and big estates are easiest to build on open land.
🚗 Car ownership
Cars and new roads let people live far from where they work and shop. Los Angeles in the USA is a well-known city that spread out widely, partly because so many people travel by car.
💰 Cheaper land
Land on the edge of a city costs far less than land in the centre. Builders can fit more homes, and bigger buildings, into the same budget.
🛍️ Out-of-town shopping
Large shopping centres need huge car parks and easy road access. This is cheaper and simpler on the fringe, and drivers like it. These centres in turn draw more homes and roads to the edge.
🏢 Business parks
Offices, warehouses and factories group together on business parks near main roads. Space is cheap, there is room to expand and there are fewer traffic jams than in the centre.
In many LICs and MICs, sprawl also happens because poorer migrants cannot afford central homes, so they build informal homes on the edge. Sprawl is therefore found in cities in HICs, MICs and LICs.
Impacts on the rural-urban fringe
Sprawl changes the land and the lives of people at the city's edge. Some impacts are negative and some are positive, so a good answer always looks at both.
| Type | Negative impacts | Positive impacts |
|---|---|---|
| Environmental | Loss of farmland and green space. Habitats are destroyed, so wildlife loses its home. More impermeable surfaces (tarmac, concrete) make rainwater run off quickly, so there is a greater risk of flooding. More traffic means more air pollution. | Few for the environment. The benefits are mainly social and economic. |
| Economic | Farmers lose land and income. Longer commutes cost people time and money. | New jobs in building, shops and business parks. More choice of shops and services. |
| Social | Small villages can lose their rural character and be swallowed by the city. Commuters spend less time with family. People without a car can find it hard to get around. | New homes are built, which eases the housing shortage. New schools, clinics and leisure centres may be built. |
Looking at the main impacts
🌾 Land and wildlife
Every new estate covers fields, hedges and woods. Farmland is lost for good, and animals and plants lose their habitat. Open green space where people walk and play also disappears.
🚦 Commuting and traffic
People live on the edge but often work in the centre or on a business park. This means more commuting, with more cars, more congestion and more air pollution on the roads in and out of the city.
🌧️ Flooding
Soil soaks up rain. Roads, roofs and car parks do not. Rain runs straight into drains and streams, which can overflow in heavy rain. Building on a floodplain makes this worse.
The flooding link is a favourite exam point. Remember to explain it in steps: land is built on, surfaces become impermeable, less water soaks in, more runs off quickly, rivers rise fast and flood.
Responses: green belts and brownfield sites
Planners cannot stop cities growing, but they can try to control where they grow. Two ideas are introduced here. Both are evaluated fully in the lesson on managing urban growth sustainably.
🌳 Green belts
A green belt is a ring of countryside around a city where new building is strictly controlled. London has a green belt around it. It protects farmland and wildlife and stops towns joining together.
🏭 Brownfield development
Instead of building on greenfield sites, planners encourage reuse of old, unused land. The London Docklands, once a busy port, was redeveloped with homes and offices. This saves countryside and brings life back to run-down areas.
Common mistakes
Do not just write "it spoils the countryside". Say what is lost (farmland, habitats, green space) and what that causes. Do not forget the positives: new homes, jobs and services. Do not mix up the two terms: the rural-urban fringe is the edge zone, while sprawl is the process of spreading.
Exam-style question
Fig. 1.1 gives made-up data for the town of Marlby, at the edge of a large city.
| Year | Farmland around Marlby (hectares) | Homes in Marlby |
|---|---|---|
| 2000 | 1,200 | 8,000 |
| 2020 | 900 | 14,000 |
(a) Define the term urban sprawl. [2 marks]
(b) Calculate the change in farmland around Marlby between 2000 and 2020. [2 marks]
(c) Explain one reason why cities sprawl. [2 marks]
(d) Explain why building new estates on the rural-urban fringe can increase the risk of flooding. [3 marks]
(e) To what extent is urban sprawl a problem for the area around a city? [6 marks]
Model answer
(a) The outward spread of a city's built-up area (1) into the surrounding countryside, often in an uncontrolled way (1).
(b) 1,200 - 900 (1) = 300 hectares less farmland (1).
(c) Land on the edge of a city is cheaper than in the centre (1), so builders and businesses can afford to build bigger estates and shopping centres there (1).
(d) New roads, roofs and driveways are impermeable (1), so rainwater cannot soak into the ground (1) and runs quickly into drains and rivers, which can overflow (1).
(e) Level 3 answer: Sprawl is a problem because it takes away farmland and green space for good, as the table shows for Marlby, where 300 hectares were lost. Wildlife loses its habitat, and more commuting means more traffic and air pollution. Impermeable surfaces also increase the risk of flooding. However, it is not only a problem. The number of homes in Marlby rose from 8,000 to 14,000, which helps with the housing shortage, and new homes bring jobs in building and shops, and new services. In addition, planners can limit the damage by using green belts and reusing brownfield sites. So, to a large extent it is a problem for the environment, but the benefits for people who need homes and jobs mean it can also be useful if it is well managed. (6)
Exam tip
On a "to what extent" question, give a negative and a positive, use the data in the table, and end with a short judgement that answers the question.