Paper Four: Unplanned Settlements – An Overview

Paper Two outlined the mainstream concepts in urban space design and showed their

limitations in creating a ‘desired quality’ or ‘goodness’ often observed in unplanned

settlement forms. This is not an attempt to overlook the improvements brought about in the

public sanitation and circulation introduced by the planning standards to regulate urban

interventions, but mainly to pinpoint the fundamental differences between the planned and

unplanned city forms and perhaps uncover a ‘better way in making a city’ that can reconcile

between the two paradoxes and overcome these differences. In this respect, the present

section will attempt to isolate the generic spatial properties underlying unplanned settlement

forms by considering examples of different settlement types that emerged within similar

environmental conditions; and similar settlement forms that occurred in different

environmental settings. Cross-cultural similarities will also be considered The definition of

these generic characteristics will constitute the building blocks for the development of the

generative model, which will hopefully create a new platform not only for understanding but

also for re-thinking the ‘frontiers’ in which urban space can be conceived, designed and

produced. The aim of this section is not to present an extensive description of the existing

‘unplanned’ settlements, but mainly to show the large variety in settlement forms but also

consistent similarities that cannot be explained or accounted for only in environmental or

cultural terms. In this respect, a sample of various settlements, villages, small and large cities

within similar and different geographical settings and across different cultures, have been

selected.

The sample includes the ‘oasis-city’ type of Saharan settlements of varying sizes, from

different locations in the desert and across countries; but also cities from the north and on the

Mediterranean Sea. About 26 settlements constitute the sample (see Fig. 3.1). These are

The Oasis-City: the Saharan Settlements

- The Mzab region: Ghardaia, Beni Isguen, Bou Noura, Melika, El Ateuf, Berrian,

Guerrara and Metlili;

- Ouargla

- The Souf region: El Oued, Guemar, Kouinine, Taghzout, Tiksebt and Zgoum;

- The Saoura region: Beni Abbes, Tamentit, Taghit and Kenatza;

- The Tuat region: Adrar, Timimoun and In Salah

- Ghadames in south west Libya

- Qairawan in south Tunisia

Settlements in the North

- The Casbah of Algiers

- Tetouan in Morocco

Fig. 3.1: Location Map

1. BACKGROUND INFORMATION

1.1 The Oasis-City

The Mzab Settlements:

The Mzab region of the Sahara, 600km south of Algiers, is located on a hostile and eroded

limestone plateau called ‘hamada’, in the heart of which, the Mzab river traces a dry course

through its valley, rising once in about two to three years after exceptional rainfall. Rain falls

on an average of ten days a year. Temperatures are very high in summer reaching over 55°C,

and low in winter, -1°C. But the difference between day and night temperatures is

considerable. The prevailing south-west winds are frequent and violent in the end of winter

and early spring.

Availability of water is a prime determining factor for settlements since agriculture

and humans require sufficient supplies of fresh water to subsist. In areas where the

average annual rainfall is less than 100mm, water is obtained from below the

ground. The most important aquifer in the Sahara, the Albien, is located in the

permeable sandstone of the continental limestone. Water from this aquifer supplies

more than 3000 wells. It is distributed to the plantations and the individual gardens

by an intricate network of irrigation channels, the width of each being apportioned to

the size of the family and garden. The distribution of water to the individual houses

was carried out by professional porters (Donnadieu & Donnadieu, 1977, p. 45).

The Mzab region is inhabited by:

- Ibadhite1 Berber speaking communities with 7 small cities all built on high grounds and the

valley reserved for cultivation (see Fig. 3.2 to 3.5); and

- Bedouins semi-nomadic tribes who live in 3 separate settlements, scattered amongst their

palm tree plantations (see Fig. 3.6).

Fig. 3.2: Mzab Valley

The survival of the Mzab cities and the expensive upkeep of the oases was mainly dependent

upon temporary and regular migration to the north of the male population, working there

mainly as shopkeepers (Etherton D., 1971, p. 187). The migrants sent money home where it

was invested in land, palm groves and houses. As the capital and chief market, Ghardaia

1 A thousand years ago this hostile valley was chosen by the ‘Ibadhites’ to build their homes (Etherton, D.,

1971, p. 186). The ‘Ibadhite’ is a Muslim sect of the ‘Kharijism’, a schism that emerged in the 7th

century following a dispute of the Prophet’s succession (Addoun A.D., 1977, p.85). The conflict ended by a dissension and constitution of the ‘Kharijit’ sect which proclaimed that the ‘khalifat’, the prophet’s succession, had to be democratically determined rather than based on lineage (Ibid, pp. 85-88). Whatever the nature of the conflict, the group was first expelled in the 8

th century from Iraq; they moved to Tahert, west of Algeria and their

kingdom lasted more than a century and a half. Tahert was destroyed in 909 by the invading Chiit Fatimides (Donnadieu & Didillon, 1977, p. 29). They fled south to Wargla and Sedrata was built nearby as the first new ‘Ibadhite ‘city in the Sahara. It was well located for trade and quickly attracted more aggressions and Sedrata was completely destroyed in 1075.

progressively enlarged its horizons and became integrated into the Saharan commercial

network and eventually established itself as a major transit centre. More recently, the Mzab

has benefited from the oil exploitation resources in the neighbouring regions. In addition to

revenues brought back through emigration, the valley counts numerous commercial activities,

with over 700 businesses in Ghardaia alone.

With seven cities of varying size, all built on high grounds, the whole oasis expands in the

lower grounds of the dry river beds, counting more than 200 000 palm trees grouped in

separate plantations near each city. In these plantations, sparse residential districts were built

and at the hottest time of the year, it is the custom for most of the population to leave the

towns and move to the summer residences. Cultivation is practised at three levels: on the

ground, the soil is reserved for crops and vegetables. The second level is for the fruit trees

and the third level is the date palm tree. Farming is mainly for subsistence and local

consumption.

Nearby each town, vast spaces are occupied by or reserved for cemeteries, constituting

inalienable and sacred spaces and as such preventing the growth of towns in these directions.

Each city has its own council of religious affairs, known as the ‘halka’ and consisting of 12

men who are key members of the community. In these communities, women are completely

separated from men, spending most of their lives in their houses; while men virtually live in

their shops. Women have also their own council.

Today, these small cities have become commercial centres with thousands of Bedouins and

people from the north settling between Beni Isguen, Ghardaia and Melika. The population of

the region in 2008 census surpassed 360 000 persons.

Construction Materials:

The construction of buildings is based on materials available locally. For the Mzab, they

consisted of:

- Limestone for the walls and wood from palm trees to span the roofs. Walls are covered

with layers of lime mortar;

- Lime (‘Jirr’) available in abundance locally, layered and ‘cooked’ in ovens of up to 2m

height. Lime is a white or greyish-white very slightly water-soluble used chiefly in mortars

and as plasters for rendering;

- Gypsum ‘Timshent’, ashy-white colour extracted locally. This plaster is dehydrated by

‘burning’ it in ovens with bottom opening and used in most Saharan buildings for making

building blocks, as mortar and also for rendering. The burning procedure and time defines the

quality of the ‘timshent’ such that the longer the ‘cooking’ time the finer the texture and the

more water resistant it becomes.

Fig. 3.3: Mzab Towns - Aerial Views

Fig. 3.4: Mzab Towns - General Views

Fig. 3.5: Mzab Towns - Street Views

Fig. 3.6: Mzab Towns - Street Views

Fig. 3.7: Metlili - General Views

Ghardaia:

- Founded in 1048 on the east bank of Mzab river, is the largest city in the Mzab valley.

- With a density of 476 I/ha, the number of inhabitants living inside the walls

reached 45 000.

- Ghardaia’s palm grove is also the largest in the valley enclosing over 60 000 palm trees.

- The city within the walls is constituted of approximately 5 000 houses, spreading like a

‘carpet’ on the hilly site, the summit of which is occupied by the main mosque, and accessed

via seven gateways, two of which link the market place to the outside.

The townscape starts spreading from ‘concentric’ rings of courtyard houses falling away from

the central monumental mosque. The urban fabric is constituted of large blocks of houses of

two to three storeys high, densely packed and separated by narrow and winding alleyways,

which become more regular in the vicinity of the large market square. These alleys can be

less than 2 meters wide and in some areas, they take the form of tunnels where eternal

darkness prevails. In some places, the alleys take the form of very steep ramps and in others

they become veritable ‘stairways’ running continuously with no ‘landings’ (see Fig. 3.3). The

market place is located at the south-west periphery of the town and is the most important in

the valley (see Fig. 3.2). It is of a rectangular shape and is entirely surrounded by an arcade

on which give many shops and boutiques and on one side, the auction market takes place.

The auctioneers walk around with the goods presented to the people seated on the ground.

This market square is the site for other minor market, clothes, household items, etc. It is as

well the converging point of the commercial streets, which are generally furnished with

masonry benches where men sit in front of their shops. These seats are also built all along the

market arcade. Outside this commercial nucleus, very few businesses and shops exist inside

the town. The mosques are usually annexed by a ‘medersa’, a school for learning the Quran.

Because of the steep slope, some streets especially those near the main mosque are made up

of two sections at different levels of height and linked to each other by ramps and staircases.

The date-palm plantation and gardens of Ghardaia are situated 2km north-west of the town.

In these gardens, summer residences are established together with small mosques, shops and

schools in order to allow longer and more comfortable stay during the hot season.

Bou-Noura:

- Founded in 1046 on the west bank of the Mzab river, at 3km away from Ghardaia and has

about 785 houses for a population of 5 495.

Beni Isguen:

- Founded in 1347 is the second largest city with 1485 houses occupying an area of

approximately 16ha, giving a density approaching 500 inhabitants per hectare.

- Beni Isguen is also built on high grounds and located at about 2.5km east of Ghardaia.

Access to the town is through four gateways, and the town walls are accompanied by several

watchtowers. The streets in the upper part of the town are steep and winding, but in the more

recent and lower part of the town, the street network becomes more regular (see Plan in fig. ).

The main mosque also occupies a dominating place at the top of the hill.

The market place of a triangular shape is partially surrounded by shops and boutiques. The

market is quite famous for its daily auctions, which usually take place between the afternoon

and the evening prayers. The market place is furnished with masonry benches built around its

perimeter and in its centre is located a public well. Every day, the same people occupy the

same seats and any absence or change of seating has a meaning (Salah F., 1987, p. 98). The

market place is not only a place where transactions and exchanges take place, but also the

centre of information, a meeting place for friends and relatives. As in Ghardaia, very few

shops exist outside the market, but some houses are used as shops exclusively serviced by and

reserved for women (Ibid, p. 99).

- The palm tree plantations of Beni Isguen expand linearly along the river bed of Ntissa and

comprise many hydraulic constructions, notably a large dam built to collect storm and flood

water.

- Visitors to Beni Isguen are not permitted to enter without a guide and there is a strict dress

code forbidding shorts and clothing that bear arms and legs. Smoking is forbidden to all

residents and visitors alike, in all public spaces and strangers must leave the city at nightfall.

El Ateuf:

- The oldest of all cities in the valley, founded around 1012 by the immigrants from Oued

Dya. It is the farthest of all settlements and the least preserved. It has about 750 houses and a

small palm grove of 15 000 trees.

Melika:

- Small city occupying a dominant position in the valley. The city signed an alliance pact

with the nomadic tribes of Chaamba Berzga of Metlili and exchanged ‘population’ as part of

the peace treaty. Despite its small size (approximately 700 houses), it had a larger population

of about 8500 inhabitants due to the fraction from the nomadic tribes that settled there.

Berrian:

- Founded in 1690 on the Bir river at 45km north of Ghardaia, by two factions expelled from

Ghardaia. It comprises about 1600 houses and its palm grove has 45 000 trees.

Guerrara:

- Founded in 1631, is the most eccentric city in the valley situated at 100km, south east of

Ghardaia. With a population of 17 719, this city is located at the cross road of the caravan

routes and its population is made up of expelled fractions from Ghardaia and Melika and also

of nomads who settled in the 17th

and 18th

centuries. The palm tree plantation is large

comprising over 45 000 trees.

Both Berrian and Guerrara ground plans exhibit more regular street networks approaching a

regular grid. Both communities share the same ethnic and cultural background as the other 5

cities. Both cities are built on high grounds with their nearby plantations on the lower

grounds to benefit from the flood waters.

Chaamba Metlili:

- small settlement founded in the 10th

century, with buildings scattered in the middle of the

palm grove, located at 35km south of Ghardaia, made up of originally seasonal-nomadic

population of 9 925 inhabitants and a large oasis of 50 000 palm trees. This settlement does

not have a market and the inhabitants go to Ghardaia for their commercial activities. The

oasis of Metlili comprises two other settlements for the semi-nomadic tribes of Oulad

Allouche, 2 329 inhabitants, and Oulad Abdelkader with 3 774 inhabitants. These tribes roam

the desert with their livestock during the hottest months in search of vegetation and water.

These small settlements are built inside the palm grove on a flat terrain and along pathways

crossing the private gardens of the plantation (see Fig. 3.7). Compared to the Mzab cities, the

fabric is constituted of single to two-storey buildings sparsely scattered amongst the trees.

The houses are organised around a larger open courtyard used by the household but also as a

stable. These settlements have only been included in the sample to demonstrate that

environmental factors or construction materials alone cannot account for the pronounced

differences between the built environments of these communities. Both communities live

within the same hostile Saharan environment, yet they developed different solutions for their

building stock, cultivation methods…

In conclusion, except for the semi-nomadic agglomerations, the Mzab cities can be

characterised by:

- A dense packing of buildings occasionally punctuated by a few open squares, a carpet-like

morphology covering the hilly sites and composed chiefly of small buildings (60m² to

150m²);

- The streets and alleys divide the settlements into distinct blocks, the shape and size of

which vary considerably (240m² to 5 500m²);

- An intricate network of streets, alleyways, ramps and ‘stairways’ of varying sizes and

configurations. The street networks of Berrian and Guerrara displays more regularity than the

more erratic ones of the other cities;

- All house plans tend to approach an orthogonal shape; and all houses are 2 to 3 storey

high;

- Building elevations are mostly blind and the only source of light and ventilation is the

small central skylights of the houses;

- All houses are furnished with separate rooms at the first floor strictly reserved for male

visitors and the access of which is through a staircase directly from the street;

- The rooftops are strictly reserved for women use;

- The construction materials in all settlements of the valley are mainly limestone, lime and

gypsum and wood from palm trees.

The Souf Settlements

- The Souf region is located north of the ‘Grand Erg Oriental’, a vast territory of sand dunes.

It is at 400km south-east of Algiers, at about 12km from the Tunisian border. Wind is the

most important constraint and the ‘bahri’, the prevailing wind from the east is the most violent

and destructive factor feared in this region.

- The oasis-city is watered by an underground ‘river’ which is very shallow from the

surface. The region has a hot desert climate with very high temperatures in summer reaching

over 55°C, and mild to low in winter, -5.4°C. Rainfall is rare and sporadic, about 75mm per

year. The population of the region was 134 699 inhabitants in 2008 census.

- The characterisation of Oued Souf as a Saharan oasis does not do justice to the particular

features of the region. The landscape as well as the lifestyle seems to be closely related to the

special techniques of cultivation. This particularity lies in the date-palm plantation method

and use of water resources. The water table in this region is very shallow from the surface

made of very fine and moving sand. The solution adopted is, not to extract the underground

water (by digging wells) and then use it to irrigate the fields, but to lower the ground level by

digging large holes, craters and planting them with palm trees such that the roots will be as

close to water as possible. In this way, water is not lost through evaporation and this

technique has resulted in a typical organisation of the oasis made up of numerous agricultural

cells, the ‘Ghout’, scattered throughout the landscape (see Aerial Photo, Fig.3.10-3.11).

Fig. 3.9: Souf- General View

Fig. 3.10: Souf Plantation System - Ghout

-

- The Souf settlements, unlike the other Saharan settlements are not surrounded by defensive

outer walls. The whole region is protected against its aggressors by its topography.

- Similarly to the Mzab, the site had been imposed upon the inhabitants of the Souf by

historical events2.

- The region of the Souf is made up of about 20 settlements, the most important one being El

Oued. A visitor to the Souf is usually surprised by the uniformity of its architecture. All

buildings are dome-roofed. El Oued is known as the city of one thousand domes (see Aerial

Photo). Similarly to the inhabitants of the Mzab, the Soufis have developed two forms of

habitat: the winter settlement with a relatively dense form of housing and the summer

residences implemented near the gardens for surveillance and maintenance of the plantations.

- These settlements are deployed on a flat terrain in the middle of a sea of moving dunes.

The settlements display a regular grid of streets providing access to rows of single storey

courtyard houses. The aerial photography and the ground plans of these settlements show

aggregates of courtyard houses connected together by a near orthogonal grid street system.

The streets are completely covered with sand which is prevented from settling on the domed-

roofs of the buildings. In proximity of the ‘ghout’, the buildings tend to follow the curved

shape originating from the circular agricultural cell. The mosque is located at the southern

part of the settlement. It is not a free-standing building and its roof is constituted by the same

modular dome element.

- The internal structure of the houses denotes a specific pattern of life which seems to have

hardly changed since the Soufis first settled. The architectural characteristics such as the

dimensions of the rooms are closely related to the construction techniques. The dome

constitutes the building module and each room is formed by two squares, the size of which is

the dome module. The houses are invariably one-storey high and the living rooms are built

around large and sandy courtyards. Access to the house is always through a dog-leg corridor

preventing thus ‘visual’ corridors from the outside. This space varies in size and is in most

cases, directly connected to a reception room for male visitors. All rooms are distributed

around the courtyard and a porch runs on one side of the courtyard in front of the individual

rooms. In some cases, the arcade is built all around the courtyard forming an inner ring of

covered and open spaces. A series of small utility rooms, such as toilet, ‘water room’ and

stable, occupy one side of the courtyard.

- Oued Souf built environment displays a visible regularity in the street pattern as well as a

distinct house type and a unique organisation of the oasis clearly based on the way water

resources are used for cultivation. A refuge land, the population of the Souf was, according to

Brunschvig, part of the ‘Kharijit’ block of south Tunisia, a Muslim orthodox sect as the

Abadhite of the Mzab (Brunschvig, R., 1942 and 1947, p. 330). This is an important factor as

the population of both regions belong to the same religious puritanist sect and both regions are

located within similar climatic conditions and uses the same construction materials (Wood

from the palm tree, Limestone and Lime known as ‘timchent’), yet their built environments

present fundamental differences at many levels, in the organisation of the oasis and the

2 According to historical data, the population of the Souf originates from the tribe ‘Ouled Zein’ which fled from

Syria towards south Tunisia. They first settled in Gabes from which they were expelled, moved westwards through Kairouan, where they were not allowed to stay, in search of a new site. They reached the region of Oued Righ where water was very abundant, but they quickly realized that the area was infested by malaria. On their way back to Tunisia, they noticed that despite the arid appearance of the Souf, water was in fact at easy reach (“Kitab El Adouani”, translated by Ferauld C., 1868, p. 173).

irrigation system, the morphology of the settlements and building types, the construction

techniques etc…

Fig. 3.11: Souf- Building Type

In Salah

- The oasis of In Salah is located in the most hostile environment in the centre of the Sahara

desert, at about 1 500km from Algiers (see Fig. 3.12). It was an important trade link on the

trans-Saharan caravan route. The area is now home to the largest oil and gas reserves;

- The oasis is made up of 4 settlements which are constantly threatened by giant moving

dunes. In Salah is cut in half by the creeping dune on the western edge which is moving at a

speed of 1m every 5 years. As buildings are being covered by its leading edge, those at the

back are reclaimed and re-occupied;

- The oasis has one of the harshest desert hot and dry climate, with temperatures surpassing

50°C in the summer months. Rainfall is almost inexistent with less than 16mm per year.

- The settlements, although many miles away from the Souf region, display the same

regularity in the street network. The buildings are constructed with red-violet clay bricks and

unlike those of the Souf are not dome-roofed.

- The oasis depends on another type of irrigation system known as ‘foggara’3, which taps

into the underground water and channels it using gravity.

Fig. 3.12: InSalah - General View

Ouargla

- The oasis of Ouargla is located 600km south east of Algiers. The city expands in the

middle of the palm tree plantation near a large salt water lake. The region has a hot desert

climate with temperatures of over 50°C in summer and below zero in the winter months.

Rainfall is very low with only about 3 days per year.

- Ouargla was an important centre in the trans-Saharan commerce specialized in the trading

gold and slaves. It was also a refuge for the Ibadhite fleeing from the north before settling in

the Mzab valley.

- The settlement forms a compact circular block in the midst of the palm grove, divided by

sinus winding streets and narrow alleyways, with the market square and the main mosque

occupying the central place (see Fig. 3.13). The city was fortified by walls. Buildings are

two to three storeys high all arranged around an internal central room, lit by a small skylight.

- Buildings are constructed from mud bricks, gypsum and lime for mortar and rendering and

wood from the palm trees.

3 Foggara is an underground conduit connecting vertical shafts and running from a higher point inside a hill.

One of the vertical shafts constitute the ‘mother well’ which taps into the water table. The other shafts are mainly for construction and maintenance of the tunnel.

Fig. 3.13: Ouargla - Aerial View

Western Saharan Settlements

- The Saoura and the Adrar regions of the Sahara lie west and south of the ‘Grand Erg

Occidental’ respectively and at about 1 200km south of Algiers. They contain a string of

small oases, extending over a distance of 160km. Only six settlements are included in the

sample. These settlements are quite ancient and were important centres for caravans. Adrar,

Timimoun and Beni Abbes are the largest cities.

- Agriculture in these regions depends on the groundwater from the Albien aquifer that

extents over 600 000km². The aquifer is very shallow, at about 2 to 6m below the surface.

- The Adrar oasis alone contains over 800 000 trees on a cultivated area of over 4 500ha.

Palm groves are irrigated by a system of ‘foggaras’, a traditional irrigation system based on

gravity and which consists of a gently sloping underground tunnel built between vertical

shafts, to collect water from the aquifer and channel it to the fields.

- The climate is hot desert with temperatures ranging from 4° to 45°C during the hottest

months and rainfall is very rare and below 10mm per year.

- Timimoun at about 200km north of Adrar, is built on high ground overlooking the valley

covered with date-palm trees. A large ‘sebkha’, a salty lake, lies further to the northwest of

the settlement.

- Beni Abbes a small city of 7 settlements of the Saoura valley is built on a rocky hill on the

left bank of the Saoura river. It is bordered to the north, east and west by the giant dunes of

the ‘Grand Erg Occidental’. The other nearby settlements with population ranging from 5

000 to 10 000 inhabitants, are located in the middle of the plantations (see Fig. 3.14).

- The fortified settlements consist of red mud brick buildings, densely packed on the flank of

the hill or in the middle of the plantations. The street network appears more regular with a

long street crossing the entire settlement and linking to other streets and alleyways (see Fig.

3.15).

Fig. 3.14: Beni Abbes & ElGolea -General View

Fig. 3.15: Timimoun -General View

Ghadames

- Ghadames is a Saharan oasis located at the meeting point of the Libyan, Tunisian and

Algerian borders, at about 450km from Tripoli (See Location Map, Fig. 3.1).

- The climate of Ghadames is extreme with temperatures ranging from 8° to about 58°C, but

the abundance of water helped agriculture to flourish which is practised in levels as is the case

in most of the Saharan oases. Rainfall is rare, a few days per year.

- It is a small mud-brick city with a total population of about 8 000 inhabitants and a total

area of 400ha including palm groves and gardens. Historical data indicated that Ghadames

was an important centre in the region due to the availability of water and the strategic position

at the trade routes used by caravans across the Sahara desert, especially in the caravan route to

Sudan and was a major link with the Tuareg territory, as trading was the most important

economic activity of the city. The slave market from Sudan constituted cheap labour for

agriculture which provided basic products and meat was provided by the nomadic Tuareg

tribes.

- The geographical site of the settlement was influenced by the proximity to the fountain, the

main water source of the settlement where the market square is located, demarcating the limits

of the different quarters of the city. The houses are clustered into dense aggregates forming

the different quarters in the midst of the palm grove.

- Despite its small size, the oasis of Ghadames is made up of four distinct communities, each

with its own language and its own distinct living quarter; yet these communities seem to be

highly integrated and consolidated. These are:

i) A Berber-speaking community which constitutes the core of the Ghadamsi society. Its

members are divided into two groups, the Walid occupying the quarters of Darrar and

Mazigh, and the Wazit occupying the streets of Jarassan, Tingesin and Taferfara.

- Most of the streets in Walid and Wazit quarters are entirely covered up and form

veritable tunnels, running under the four-storey high houses. These streets open out

occasionally into covered squares with small light wells. The streets are usually 2 to 3

metres wide and are furnished with built-in masonry benches, used by the male

population for their meetings. The houses of Walid and Wazit quarters are connected at

roof level by an intricate network of walkways linking all the rooftops and terraces

together and are strictly used by women for their movements across the settlement.

- The ground plan constituted of about 1275 houses, shows a very irregular and tortuous

street network which demarcates blocks of houses of various sizes and in many cases,

access to houses is gained by narrow and very dark cul-de-sacs in the form of labyrinths.

There are a few public buildings and spaces, to include mosques, washing areas for

clothes and dishes, public baths and several sheds for communal wood storage and

communal stables.

- The houses in this part of Ghadames are of three to four storeys high. They are

invariably built around a central living room. On entering the house (see House Plan in

Fig. 3.16-17) from the street, there is a small hall which gives access to one of more store

rooms fitted with doors where agricultural implements, tools, charcoal and wood are

stored; but also to a reception room for male visitors. At the far end of this entrance hall,

a staircase leads to the central living room which constitutes the heart of the house. It is

lit by a large unglazed skylight in the centre of the ceiling and its walls are richly

decorated with painted designs and its floor thickly covered with mats and rugs. Two of

three windowless rooms occupy the sides of this central room. A staircase leads to the

upper floors where the kitchen to the walkways at rooftops.

ii) An Arabic-speaking community, Ouled Bellil; they inhabit a separate quarter known

by the same name (see Fig. 3.17).

- Bellil is the only quarter of the city where the terrace system is not developed. Unlike

the other areas of Ghadames, the streets in Bellil are not covered up by building spanning

over and are not furnished with masonry benches. The quarter takes a linear development

with the largest street located at the periphery and part of this street is delineated by the

remaining of the town walls.

- The houses (about 200) are all one-storey high and the living rooms are built around

an interior open space, with a yard used as a stable at the rear of the house (see Plan, fig.

3.17). A staircase links the ground floor to the roof terrace used for drying and also for

sleeping in summer. The isolated terraces are surrounded by high parapet walls of about 2

metres high, and unlike the other parts of the settlements, Bellil is the only area where

women gather unveiled on the streets outside their homes.

iii) A Hausa-speaking community, consisting of freed slaves who originally served the

Berber-speaking community. They also inhabit the quarter of Ouled Bellil;

iv) A Tuareg-speaking community locally known as ‘Lamtayyan’. They occupy a

separate area called ‘Addaharat’, situated at 2.5km west of the city. They live in tents

spread over an open area, surrounded by their livestock.

The society of Ghadames is very complex in its structure; it is clearly divided into several

groups, both geographically and socially and this division also exists in their language.

There are also differences in men and women speeches. This social organisation into

groups is most apparent in land tenure, water and palm tree ownership, recorded in the

manuscripts kept for centuries in the oasis. Land, water and palm trees are collectively

owned by the groups.

Fig. 3.16: Ghadames

Kairouan

- Founded in 670, Kairouan is an ancient and historical city and an important centre for

Islamic learning. It is located 50km for the eastern coast of Tunisia, at 184km south of Tunis.

- In 745, the ‘Kharijit’ Berbers captured the town which flourished and became famous for

its luxuriant gardens and olive groves.

- Its great mosque built by Oqba Ibn Nafi, was a famous university for Qoranic teaching. It

is a very large and impressive building covering an area of over 9 000m².

- The climate is of desert nature, very hot in summer and mild in winter with temperatures

varying between 6 and 45°C and rainfall is very minimal, below 24mm per year.

- The city unfolds on a flat plateau in a compact fabric punctuated by a network of

narrow streets and winding alleyways many of them in the form of dead-ends (see

Fig. 3.18).

- The Great Mosque and the market place and streets are the north eastern periphery.

- The buildings of 1 to 2 storeys high are all arranged around an internal courtyard.

- Red clay bricks are the main construction material.

Fig. 3.18: Kairouan

1.2 Cities from The Mediterranean Coast

The Casbah of Algiers

- Ancient city of over 50 000 inhabitants, built on a hill sloping down towards the sea.

- It has a Mediterranean climate with hot dry summers and moderate winters with

temperatures ranging from -2° to 32°C and rainfall of about 598mm per year.

- The city is divided in two parts, the lower and higher casbah with the Dey palace at the

highest part of the city. The main characteristic of the urban fabric is the street network which

is constitutes in addition to the narrow streets, very steep ramps of continuous steps cutting

through the high gradients (see Fig. 3.19).

Fig. 3.19: Casbah of Algiers

Tetouan

- Located on the Mediterranean coast is one of the major ports of Morocco. It is only a few

miles south of the Strait of Gibraltar.

- It has a Mediterranean climate with hot dry summers and moderate mild winters with

temperatures varying between 8°C to 30°C and rainfall of about 650mm.

- The urban fabric is characterised by the compact massing of buildings covering the sloping

side of a hill with narrow irregular streets and ramps (see Fig. 3.20).

Fig. 3.20: Tetouan

Fig. 3.21: Ostuni - Street Views

2. General Morphological Characteristics of Unplanned Cities

The urban form of unplanned cities is predominantly pedestrian, built over time through

individual actions, and the processes that generate these forms are slow and result from the

millions of individual decisions made by citizens when constructing their homes. These

decisions are based on a general consensus of principles about what is ‘acceptable’ to build by

all. The urban rules used in medieval towns were known as ‘proscriptive’, from ‘proscriptio’

which means public notice of outlawry. This means that people are free to build whatever

they want as long as it is within the ‘acceptable’ (Hakim B., 2008).

The present study attempts to define the ‘acceptable’ by looking at the morphological

characteristics pertaining these cities and construe the few rules and restrictions underlying an

otherwise random growth process. It must be noted that an extensive analytical study was

carried out by the author using Space Syntax, in the course of the preparation of the PhD.

Thesis and most of the physical data and descriptive material collected in person and on situ

during numerous field-works is from that research work (Salah S., F., 1987).

The general impression that may be gained by a casual examination of the ground plans and

descriptive material of the settlements in the sample shows consistent similarities but also

fundamental differences.

- All settlements form a continuous compact mass regardless of the topography and the

geographical location. This dense packing of buildings of over 85% ground coverage is only

occasionally punctuated by a few open squares.

- The streets and alleys divide the settlements into distinct and irregular blocks, the shape

and size of which vary considerably;

- All settlements display an intricate network of streets, alleyways, ramps and ‘stairways’ of

varying sizes and configurations, from the erratic and irregular networks to grid-like street

structures;

- All house plans tend to approach an orthogonal shape;

- The houses are one to three-storeys;

- Building elevations are mostly blind and the only main source of light and ventilation is

the central skylight and windows if they exist are usually small.

- The construction materials in all settlements are all local mainly limestone, lime and

gypsum, mud-bricks and wood.

Fig. 3.22: The Mzab – Street Networks

Fig. 3.23: The Souf - Street Networks

Fig. 3.24: Street Network of Western Saharan Settlements

Fig. 3.25: Street Network of Coastal Cities and Saharan Settlements

3. Bottom-up Topology: The Principle of Connectedness

Topology is the mathematical study of shapes and spaces and their properties which remain

invariant under certain deformations including stretching and bending (Wikipedia). Topology

is therefore concerned with the basic properties of space, such as connectedness, continuity

and boundary, those qualities of objects that remain constant despite a certain kind of

transformations. To put it more simply, Topology is the study of continuity and connectivity.

Clearly, one of basic spatial principle prevalent in the organisation of these settlements is the

high connectedness and contiguity in the massing of buildings; that is the buildings

boundaries are continuously joined allowing open spaces only for access. But the way in

which they connect cannot be predicted and depends only on the available choices when they

are erected. These choices are restricted only by the ‘proscriptive’, in the sense that buildings

can be placed anywhere as long as they do infringe on the neighbours’ boundaries or openings

(access ways and windows). Connection possibilities available to the builders during

construction and local topological negotiations maintain consistency and introduce

unpredictability and randomness in the formation of these unplanned settlements. The

ensuing chapters demonstrate that it is this random dimension in the topological properties by

means of using probabilistic connectedness as part of the underlying logic of the form-

generating process which creates both these recognizable patterns and their variations.

4. Generic Properties of the Unplanned Settlements

From the examination of the sample, it can be safely concluded that:

- The basic component units of all settlements are buildings of a near rectangular or square

geometry, defined by a closed boundary demarcating the open spaces that form a continuous

system of streets and alleyways. These open spaces have been generated following a bottom-

up topology connecting segments of streets together as they emerge to provide access to the

buildings.

- All settlements are aggregates generated by a bottom-up growth process based on

connectivity possibilities of the component units;

- The most basic generative rule in a bottom-up topology is the ‘Connectivity’ principle

creating relations and interdependency between the elements, resulting thus in the potential

for self-correcting, so that changes in the connectedness of one component has a direct impact

on its immediate surroundings;

- Restrictions and control on the connectedness principle determine the basic rules for

aggregating and maintaining an order;

- The most basic inherent activity to all settlements is ‘movement’;

- Path formation takes precedence to Accessibility;

The basic requirements for a model to address the points outlined above are that the model

should:

- transcribe the dynamic iterative procedure of the bottom-up growth process;

- incorporate fewer basic components;

- be based on a fewer simple local rules to depict the connectedness possibilities and

building aggregation;

- be at least partly non-deterministic to allow for variation on the theme provided by the

rules.

The most challenging task in defining the model is: how to use the same universal rules of

building aggregations that can yield at once the similarities and the pronounced differences

observed in the existing settlements? How to build a form-generating model operating only

on units aggregations that is capable of producing both self-similarity and differentiation

observed in the natural4 urban formation? The answer lies in the introduction of two parallel

systems but intrinsically dependent, ‘Building Massing’ and ‘Circulation’, acting on and

4 The word ‘natural’ as opposed to ‘planned’ is strictly used in this sense.

interacting with the local environment. The probabilistic control mechanisms and feedback

procedures of these two systems create possibilities for Growth, Persistence and Adaptation.

In Paper Five, a full presentation of the model follows including rule definitions and the

generative tools and techniques in an attempt to develop an instrumental medium for

exploring urban space design on the basis of information and knowledge of unplanned

settlements.

Summary and Conclusion

This section focused on the fundamental characteristics of the unplanned cities by examining

a sample of 24 agglomerations from the Sahara desert as well as the Mediterranean coast and

even from European locations (see Fig. 3.17). This seemingly unrelated collection displayed

some inherent similarities but also substantial differences which cannot be accounted for only

on the basis of environmental or cultural factors, but are strongly related to the underlying

ordering principles and the mechanisms involved to maintain the emergent order. The

consideration of these systems and their bottom-up topologies formed the basis for defining

the basic requirements of the form-generating model.