Activities  Cities from Space

Following DEWA~wide efforts to document environmental changes during the last thirty years in selected sites around the world, several satellite images were studied at GRID-Europe. It concerns the following cities: Bucharest, Geneva, Kiev, Port-au-Prince and Tehran.

A) Bucharest: Population dispersion and air pollution

Bucharest lies in the southeastern part of Romania, halfway between the Danube River and the Southern Carpathian Mountains on the banks of the Dīmbovita River. As the country's principal political, cultural and economic centre, it is at least five times larger than any other Romanian city. Urban Bucharest has more than doubled in population and land area since 1948 as a result of natural population growth, industrialisation and political centralisation. This has caused the city to become increasingly built-up and congested.

Today, 16 years after the fall of the Communist Party and re-privatisation of land, Bucharest faces the problems of population growth and dispersion from the centre to suburban areas. The city's dispersed population and rising levels of car ownership have resulted in more traffic congestion together with air and noise pollution. The growth of industry in the suburbs also contributes to air pollution.

1979: Extensive agricultural areas exist both within and outside of the city limits and the surrounding ring road. Large forests spread to the north and west of the city. As revealed by the differing colours of the agricultural lands, the following images were taken during different seasons of the year.
At this stage, Bucharest was still relatively compact, with the high-density area concentrated within a seven-kilometre radius of the city centre
1988: A quick glance at Bucharest in this image reveals that the townscape was dramatically restructured and transformed during the presidency of Nicolae Ceaucescu in the 1980s. Until this time, modern development did not upset the traditional urban fabric.
But between 1980 and 1989, a number of villages on the outskirts of Bucharest were dismantled. Their citizens were forced to move into the city to make way for projects such as the expansion of the airport and the building of the Bucharest-Danube Canal (Dîmbovita), which now divides the city into two sections.
Meanwhile, about a quarter of the old city was demolished to construct massive new state buildings, such as "The House of People", the world's second largest building after the Pentagon, and to clear a path for the Victory of Socialism Boulevard.
2001:This image illustrates that the city has become denser in the west, east and southeast. Urban growth is occurring both inside and outside the ring road. The city is expanding outside the ring road and beyond the city boundaries to the west, and inside it on the northern side.

 


B) Geneva: Urban sprawl and pressure on the surrounding countryside

Wrapped around the southwest tip of western Europe's largest lake, the City (and Canton) of Geneva lies in a basin wedged between the Alps and the Jura range. Geneva is the sixth most populated canton of Switzerland (434,473 inhabitants in 2003) but one of the smallest in area. It shares a border of 5.6 km with the Canton of Vaud in the north but is otherwise entirely surrounded by French territory. Geneva hosts many international organizations, including the European headquarters of the United Nations and the International Committee of the Red Cross (ICRC). In addition, many foreign firms have relocated to Geneva to take advantage of its favourable tax regime.

Geneva accounts for 75% of all jobs in its cross-border basin but houses only 57% of its population. While a magnet for employment, Geneva lacks sufficient land for new construction. Neighbouring territories, however, do have space available for building. During the last few decades, the agglomeration of Geneva has increasingly exceeded its cantonal borders, spreading into the Canton of Vaud and neighbouring France. Despite a continuing influx of foreign workers, immigration and growth have remained relatively stable from 1990 to 2000 when the population increased on average nearly 1% per year. But in 2001, Geneva registered its highest recent growth rate of over 2%, while the increases in 2002 and 2003 were 1.3% and 1.6%, respectively. Suburban development puts pressure on the agricultural lands and natural environment. In Geneva, these problems are accentuated by the cross-bordernature of the urban agglomeration. The Canton has adopted a policy of territorial development favouring "urbanization towards the interior", or inward urbanization. It is fighting against the dispersal of the built zone and trying to
preserve as much agricultural land as possible. Geneva's goal is to gradually increase the density of the urban centre and the suburbs and promote continuous urban space, while allowing some degree of development in outlying villages. This policy has made it possible to limit harm to the countryside, but contributes to the unmet demand for new housing. The Canton has reclassified limited parts of the agricultural zone that are contiguous with the built area, but even this has not been sufficient. As a result of the housing shortage, real estate prices are high and rising.
Despite its efforts to promote inward urbanization, the Government finds that over the last ten years the population has been increasing more in the suburbs than in the centre. Consequently, traffic problems are worsening, with major congestion at peak hours in the morning and evening on both major and minor access roads.

As illustrated in the below Landsat satellite image of 2003, five kilometres from downtown Geneva, on the "Geneva - Pays de Gex" axis, the contrast in land use on each side of the border is striking. The very dense construction on the Swiss side is squeezed against the airport, while on the French side urbanization is limited and the landscape is punctuated by old villages and villa zones alternating with farmlands and forests. The double obstacle of the international border and the four kilometres of airport runways create this striking contrast - although the growing pressures suggest that these barriers may no longer suffice to bar expansion into the surrounding French territory. As the Geneva - Pays de Gex and the Geneva - Annemasse axes become saturated, urban expansion is bulging towards another axis to the south and southeast of Geneva (St. Julien, Archamps).

Today, with the Swiss-European bilateral accords and facilitation of regional mobility, the border no longer acts as a restriction to Geneva's development. Geneva's limited space will continue to make the undeveloped lands of neighbouring France, which also offer a lower cost of living, increasingly attractive. Swiss and French authorities face the challenge of coordinating their efforts against uncontrolled development, which would risk irreversible impacts on the environment, the quality of life and the region's agricultural nature and socio-economic fabric.

09.10.1972 Landsat MSS Natural colour, Equalised histogram
17.07.2003 Landsat ETM+ Natural colour, Equalised histogram
Composite image of IRS (20.03.2000) and SPOT (17.06.2000)

 

C) Kiev: Urban growth and waste management

Kiev (or Kyiv), Ukraine's capital and largest city, is located in the north-central part of the country on the Dnieper River. It is Ukraine's leading centre for industry, commerce, science and education. The city grew enormously between 1950 and 1980. A powerful technological complex with dozens of industrial companies was created, employing many highly skilled personnel. Kiev also became an important military centre for the
Soviet Union. Because these developments created a large demand for labour, migration increased from rural areas in both Ukraine and Russia. Given that land had no formal value under socialism, planners were not motivated to economise on space. Massive suburbs and an extensive transportation system were built to accommodate the expanding population, although many rural buildings and tree groves survived in the city's hills. The 1986 Chernobyl nuclear disaster, 100 km to the north of Kiev, brought in thousands of refugees from the accident zone. In 1991, Kiev became the capital of an independent Ukraine.

According to the 2001 census, Kiev is home to about 2.6 million people. Other estimates based on recent migration patterns place its population at closer to four million people. Rapid urban expansion together with the economic transition and the privatisation process have created urgent
environmental problems for the city. These include air pollution from energy and transport emissions, pollution of surface and underground
waters by sewage and a decline in biological diversity. Another key environmental challenge for Kiev is coping with consumer, industrial, toxic, radioactive and other wastes. In 1998, some 300 enterprises and organisations in the municipality were using technologies whose by-products include radioactive waste. In addition, within the city limits there is a state-owned centre for depositing radioactive wastes transported in from around the country. A lack of effective new technologies for treating wastes, as well as a lack of space for landfills, is causing waste to accumulate on city land. Unsanctioned dumps of toxic industrial wastes are polluting the area's soil and water. There is an urgent need for more specialized wastetreatment facilities.

 

1975: Extensive areas of forested park, both natural and replanted, lie within the city limits. Different vegetation zones occupy 43% of Kiev's municipal territory. The Dnieper River forms a branching system of tributaries, islands and harbours. The older right-bank (western) part of Kiev is hilly, with ravines and small rivers. The left-bank (eastern) part of the city is built in a valley. Some parts of the left bank have been reinforced with sand and dams.
2001: One particularity of Kiev is the significant decentralisation of its urban network and its different levels of urbanisation. Alongside densely built-up older zones, peripheral territories are nearby areas covered by woods or meadows. Several satellite towns and smaller settlements surround Kiev.
Comparing the images from 1975 and 2001 shows significant urban expansion in both the northern and southern parts of the city, as well as a considerable amount of construction spreading into neighboring vegetated zones. This is putting increasing pressure on natural reserves, and is an important factor in the considerable decline of biological diversity in the Kiev agglomeration.

 

D) Port-au-Prince: Urbanisation, deforestation and water shortage

Port-au-Prince, capital of Haiti and the country's chief seaport, is located on a bay of the Gulf of Gonaïves. It was founded in 1749 by French sugar planters. The city is laid out like an amphitheatre: within a short distance of the port, the topography climbs rapidly toward a mountain range with peaks in the 2,000-2,500 meter range. Extensive and densely developed urban environments have been carved into the hillsides. The urban growth of Port-au-Prince has led to the proliferation of shantytowns and deterioration of people's living conditions.

According to the World Health Organization, roughly 98 percent of Haiti is deforested. Forests are cut to make charcoal, which is used for cooking fuel. Without the trees and their roots, sufficient amounts of water cannot be absorbed into the soil and Haiti's hard rains simply wash the country's rich topsoil into the rivers and oceans, and soil clogs clean-running streams that feed lakes and springs. Lake of Etang Bois Neuf, about an hour outside of Port-au-Prince, has nearly disappeared. Just as less water is flowing into aquifers, the demand for water is exploding. Fifty years ago, Port-au-Prince's 18 springs supplied clean water to a population of approximately 200,000. In 2003, Port-au-Prince had an estimated population of two million.

06.02.1975 Landsat MMS
10.01.2000 Landsat ETM+

The comparison of these Landsat images demonstrates urban growth toward the southeast (in the direction of the towns of "Petionville", and "Kenscoff") and also toward the east (in the direction of the towns "Thor", "Carrefour" and "Mariana") of the city.
This growth is observed as major urban densification and extensions with a change from farming and forest land use.
The network of roads is more evident in the image from 2000, just as the "runner" effect, provoking new settlements or urban areas, which have been constructed along the length of the new lines of communication.
Greater urban consolidation has also taken place in the Port-au-Prince extension on the west side of the bay toward "Leogane" and in the northeast part of the city toward "Drouillard." A notable change landuse from farming to urban can be seen in these zones. Additionally, in this part of the scene, the landscape changes from farming to urban, specially over the highway that goes from "Drouillard" to "Croix Des Bouquets," creating a new urban extension.
The greatest growth of Port-au-Prince is "outward" (like the majority of the cities in Latin America), occupying mainly surrounding agricultural and forested zones.

 

E) Tehran: Impacts of urban expansion on water resources

The Iranian capital of Tehran extends from the southern slopes (1,700 meters above sea level) of the Alborz Mountains into the Dasht-e Kavir desert in the south (1,100 meters above sea level). Compared with Iran's many ancient cities it is a relative newcomer, having served as the capital city for only 200 years.

Ranking among the world's largest metropolises, Tehran is also part of Iran's most densely populated province. The latest census (1996) records a population of 11 million for Tehran province, with 6.7 million in the city itself. While the city's annual population growth dropped to only 0.9 per cent from 1986 to 1996, the province as a whole has grown by 4.7 per cent per year, and is projected to exceed 15 million individuals by 2012.

Tehran province contains only two per cent of the total water resources of semi-arid Iran but already houses 20 per cent of the country's population. Geologically, the Tehran plain can be likened to a bowl, limited to the north by high mountains and to the south by the hills of Kahrizak. Tehran is far from any major river and relies on water supplies located at a distance from the city.

The slow development of reservoirs, water mismanagement and a series of dry years have combined recently to diminish water resources dramatically. Meanwhile, the lack of sufficient sewage facilities results in most human wastes being discharged untreated into domestic sewage wells, a situation leading to deterioration of the groundwater quality. At the same time and as the city has grown, more potable water is being imported into the city. This water in turn is used and adds to the existing polluted groundwater, particularly in lower, southern Tehran, where flooding often occurs.


Historical growth of Tehran 1881-1956 on the image of 18.07.2000


25.07.1975 Landsat MSS colour composite RGB, bands (3,4,1)

Year 1975: Tehran once received adequate water supplies from the Amir Kabir Dam on the Karaj River (in the extreme upper left of the image; the shadows of the surrounding mountains make it appear dark) and the Latian Dam (on the right of the image, above the city) on the Jaj-Rud.

Clouds cover small parts of the image. To the south and west of the urban area lies a belt of fertile land, which appears as green.



19.09.1988 Landsat TM colour composite RGB, bands (3,4,1)
Year 1988: The Lar Dam was completed in 1980 (see lake in the extreme upper right of the image) to meet Tehran's growing demand for potable water. The dam is built on the River Lar, which discharges northwards into the Caspian Sea.This image illustrates the city's geographic expansion and increased density, as well as the significant decline in reservoir levels. It also reveals the important loss of green spaces to the north of the city.
The expansion and growing density of the city are quite noticeable in the west and northwest. The mountains to the north and east and the desert in the south are natural obstacles to Tehran's further sprawl.
The urban texture is increasingly expanding towards the west of the city, where there are no natural limits to development.
 

18.07.2000 Landsat ETM+ colour composite RGB, bands (3,4,1)
Year 2000: Here the city nearly connects with the province's biggest suburban area, Karaj (not included in the available images; Tehran's expansion, however, is so extensive that a part of Karaj is visible in the left side of the image of year 2000.
Given its geographic circumstances, one can ask whether Tehran is reaching its natural limits of expansion, or whether its water problems will eventually limit further growth.

 

Posters of the following cities have also been created by other GRID regional offices: Brasilia, Everglades, Las Vegas, London, Lusaka, Nairobi, Mexico city and San Francisco.

By Saman SALARI SHARIF