Sustainable Qualities of Vernacular Architecture in Quest of Sustainable Architecture in the Desert Environment: Case Study of Kesar of Timimoune

The concept of sustainable development has won many adherents in the world, as it aims to achieve social and economic development and preserve the environment in the light of current climatic changes, which are considered one of the biggest challenges, In particular, for the desert environment in developing countries such as the Algerian desert; For decades, man has been able to survive in this nature by creating oases, It is a fragile ecosystem entirely entrusted to the care of its inhabitants. The aim of this article is to determine the qualities of sustainability in vernacular architecture of Algerian desert. Through the case study, which is the city of Timimoune, the article is divided into two parts. The first part is a morphological analysis of the Kesar of Timimoune urban pattern; the second part is to extract the sustainable qualities related to the morphological dimension of the Kesar of Timimoune, which is considered as principles and references for designing modern sustainable cities in arid environments.

Introduction

In the southwest of Algeria, especially in the Oasis of Timimoune, the past is all around us; we live our lives against a rich backdrop formed by tangible and intangible heritage, starting with buildings, irrigation systems, social practices, rituals and festival events, skills, and performing arts.

Kesours, kasbah, and foggara are vernacular architecture that provides character and distinctive identity to the region. Kesours are the centers of life in southern Algeria (Echallier, 1972). The kesar is characterized by the maximum functionality and rationality of its architecture, with natural components: Vegetation, clay, and earth.

In Timimoune desert, where nature is harsh, man was able to adapt perfectly to his environment, relying on a deep knowledge of his environment and on the exploitation of available raw materials. Vernacular architecture summarizes this great homogeneity between man and his environment.

Analyzing the morphological and technical values of vernacular architecture in a specific context—Timimoune city—will link two important topics and thus highlight the most important sustainable qualities, which will serve as new guidelines for sustainable design in the arid region.

Methodology

Method and Tools

The method used is based on the morphological analysis of a part of the Kesar of Timimoune; in a traditional environment, a building only takes on its full meaning in relation to the fabric in which it is inserted. On the other hand, even in the absence of any monumental architecture, there are sets of buildings which stand out for their coherence and unity more than for the originality of certain of their components.

It, therefore, seems necessary to identify principles of analysis that highlight not only the richness of the vocabulary of Kesar but also the richness of the syntax. In fact, the quality and diversity of the fabrics arise from specific modes of combination of spaces and builds.

After having analyzed the Kesourian tissue by a morphological analysis and defining the principles of this tissue, a matrix analysis will be carried out to extract sustainable characteristics of both urban and architectural levels.

Morphological Analysis

The analysis process depends on the decomposition of the urban system into four subsystems: the plot system, the road network system, the buildings system, and the open space system.

These subsystems are then analyzed into three aspects:

• Geometric aspect
• Dimensional aspect
• Topological aspect

However, the formulation of a method of morphological analysis of Kesourian tissue allows:

• To reveal the sustainable qualities of a KSAR or a kasbah to be anticipated, nonetheless needed to be explained.
• To define new guidelines for sustainable design in the arid region.

Interest of the Decomposition

The ambition of this study is to enable the acquisition of a finer and more in-depth knowledge of traditional building forms. There should be no pretensions as a historian, and therefore, no analysis of history; even less, we will find there a general reflection on socio-economic problems, city practices, or the experience of urban space. This is a study of a morphological nature.

The purpose of this type of analysis is to bracket the multiple interactions that link forms to a social, economic, and cultural context.

In order to avoid giving reductive diagrams, which ignore the specificity of the tissue, we considered our problem learning.

Analysis Approaches

The four organizers’ systems of the urban system are:

1. Plot system analysis

The plot system is a system of partitioning the space of the territory into a certain number of land units, the parcels. The plot, therefore, fragments territory (Pinon, 1991):

• Topological aspect: After having shown all the plots and determining the greater or lesser continuity, we found that:

-The new districts (after 1900): The shape of the plots in the Kesar is regular, the two main directions of the frame are of importance roughly equivalent, and the plot boundaries have the same continuity in one direction and in the other.

-The old center, especially the first nucleus: The plot is more dance, and the shape of the plots is less regular. The frame has evolved, become more refined, and become denser, integrating aliasing by adding or subtracting fragments of plots from one to the other by inheritance and fragmentation.

• Geometric aspect

The main direction of the urban plot in the Kesar of Timimoune is the same as that of the agricultural plot on which it rests; (Fig. 1) the dominant orientation of the latter is dependent on the direction of flow of the irrigation water brought back so far by the system of Foggaras and Seguia (perpendicular to the level curves) (Fig. 2) so a greater number of plots will be able to take advantage of this water.

Fig. 1. Guideline parallel to the contour lines.

Fig. 2. Guideline perpendicular to contour lines.

Perpendicular to the dominant direction, the parcel limits also constitute in some places of the Kesar continuous lines, but which are not directional because unlike the 1st direction, which conditioned the plot layout, this one is the result of the plot layout superimposed on the size of the plot and the khachba (construction module).

In the most recent parts, we do not find hierarchy; the guidelines come perpendicular to the agricultural paths (Fig. 2), or they constitute a non-hierarchical plot; this non-conformity with the old is probably the consequence of the lowering of the level of the foggaras, agricultural land becomes sterile, the agricultural plot loses its importance, and new plots are formed spontaneously.

• Dimensional aspect: When the plot has the time and the opportunity to evolve, subdivision operations generally appear, which can lead to a reduction in the size of the plots. This is confirmed at the Kesar of Timimoune, where we find an old part characterized by a dense plot and, therefore, small plots (Fig. 4). The more one goes towards the most recent parts, the more the plot widens, and the plots become large (Fig. 3).
• Plot analysis: The most general shape of the plots in Timimoune is the rectangular shape, which extends perpendicular to the guiding lines.

Fig. 3. large plots on the outskirts of the center.

Fig. 4. Plots in the center of small dimensions.

Three types of plots were determined in Timimoune:

- A rectangular plot directed towards dense agricultural roads and presenting crenellations; this corresponds to the plots of the old cores.

- A rectangular parcel directed towards the dense and non-crenellated agricultural roads, it corresponds to the extra-mural extensions in the old part.

- A stocky plot close to the square corresponding to the most recent parts.

2. Road system analysis

The road system is the linking system of the space of the territory. It is constituted by all the circulations of function and of variable importance; the network is intended to innervate the plots and, therefore, to connect the different parts of the territory between them.

The road network of Timimoune is on the axis AL-Mindjour a linear way which crosses the Kesar from one end to the other, parallel axis of 1^st Nov Street (Bellil, 2003). And another axis in loop which intersects in some places, and which is inserted between the two previous ones.

A series of parallel tracks are superimposed perpendicularly to these axes, thus forming a false fishnet frame which generally constitutes plot in length. This frame is punctuated from one place to another and on the axis of formation of small places (Rahba) (Fig. 5), which constitute spaces of social exchanges and communication at the level of each fragment.

Fig. 5. The road system and public space (Rahba Sidi Moussa) in the Kesar of Timimoune. Source: author.

This system is, in fact, only the superposition of agricultural, territorial, and training courses. Within this framework, several subsystems are included; these are often linear arborescent systems with an exit, going from public to private. This hierarchy of pathways is even more accentuated in the old cores (Fig. 6).

Fig. 6. Agham tadmait (residential area in the Kesar of Timimoune) shows arborescent road system source: author.

3. Built System

Built system includes all the masses constructed urban form, regardless of their function (housing, equipment) to their dimension. It is the system that brings together all the built masses.

There is a great homogeneity between the built system and the plot system in all the geometric shapes and dimensional aspects, expect for the singular elements like the towers and the surrounding walls.

4. Open space System

“Urban open spaces are integral parts of city life to provide better quality of life” (Sharmin & Perveen, 2019, p. 20).

Open space system is all the parts not built urban form, that these spaces are public (squares, plazas, streets, etc.) to the private (courses, gardens).

The open space is square and rectangular. It represents approximately a third of the surface area of the house. Open space at the level of urban areas also represents the equivalent of a third of the surface area.

Results and Discussion

The Morphological Structure of Kesar Timimoune

Morphological analyzes of Kesar Timimoune show that the buildings, palm oases, and Foggaras (source of water) form an integrated unit, as each of them depends on the other in its formation. The analyzes also show that the kesar is a compacted fabric composed of several Kasbahs that expanded over time to form separate tissues (Martin, 1863), each of which has its own mosque and public spaces, they are all connected via a street (El-Manjour) that extends from the beginning of the Kesar to its end.

The Kesar Orientation

The Kesar of Timimoune, implemented on flat land, extends from northeast to southwest; the main streets of the Kesar follow the same orientation to benefit from the wind (humid) and the exchange of shade and sun in the streets. The facades are huge and blind oriented towards the north and south in general for better sunshine; the patio inside the houses creates introverted facades that ensure adequate lighting and ventilation; the Kesar strategic location next to palm groves helped achieve clean and humid air and, therefore, energy saving and sustainability were achieved.

A matrix analysis of the traditional fabrics of Timimoune is carried out on the basis of the morphological analysis of this fabric, which aims to highlight the sustainable qualities of the traditional settlement of Timimoune city (Table I).

Table I. Sustainable Qualities of the Traditional Settlement of Timimoune City (Kesar of Timimoune)

Criteria	The kesar of Timimoune	Illustration
Environment context
Life cycle assessment	The Kesours constitute an integrated life cycle (Water–Building materials–Agriculture–Food).	Life cycle assessment of oasis
Land use and brownfield reuse	High level: Mixed lund use (commercial/habitat/equipment).	Mixed land use of traditional urban fabric
Energy use efficiency	Waste eddar which ensures natural light/natural ventilation for all rooms.Adobe and clay which provides thermal insulation.The homes are designed in a way that they overshadow each other.
Waste management	All domestic waste is immediately transformed into animal feed.Clothes wastes are transformed as carpet. Recycling of building materials.Human and animal waste is turned into agricultural fertilizer. The waste of palm trees turned into pots.
Renewable energy	–	–
Natural resources Conservation	Optimizing water (Kial Lma).Preservation of foodstuffs specifically dates and wheat grain through drying-optimizing land use (small houses).
Construction techniques and process	An ancient technique of building based on natural resources (adobe/clay).
Water efficiency and management	The use of foggaras and the use of a very precise unit of measurement for the distribution of water (kial l ma).
Biodiversity protection	The presence of animals at home (Rahbet el Ghabar) and the direct relationship with the palm groves.
Public and green area	Court yard palm groves 60.
Pollution and emission reduction	Using walkable street inside Kesar. Low energy use.
Economic context
Life cycle cost (LCC)	Low LCC
Locale business and job opportunity	Artisanal cultural and agriculture activities.
Locale agriculture and food production	Seasonal products: dates, wheat grains, some vegetables.
Social context
Mixed use urban	Court yards. Street mosque.
Social inclusive design	High level (public courtyard/house courtyard/street/masque)
Security	High levels due to due to the hierarchy of street and public spaces and the good cohesion social in all Kesar.
Walkable street and accessibility	Hierarchical streets (public, semi-public, private) connect all the spaces of Kesar. Half-covered street system. Twisted street system.
Quality of services	Bad quality of service
Arts and culture in community	Several Traditional Art and Culture Association.
Air-water quality	Good quality.
Schools and education	A high level is due to the state’s policy of bringing educational institutions closer to the Kesar, in addition to the presence of mosques in the Kesar that contribute to religious education.

Matrix analysis of traditional fabrics of Timimoune is divided into three categories: environment, social, and economic context (Basiago, 1998). Each category is divided into subcategories according to Sustainability assessment criteria (Hamedani, 2014).

Environment Context

Life Cycle Assessment

Morphological analysis of Kesar Timimoune shows that the buildings, palm oases, and foggaras (water source) form an integrated unit, as each depends on the other in its formation (Bana, 2015), forming an integrated life cycle (water–building materials–agriculture–food). One-click life cycle assessment (Fig. 7).

Fig. 7. Life cycle assessment of oasis. Source: Bisson (1957).

Natural Resources Conservation and Waste Management

Morphological analysis proves that this environment is the result of a continuous process that involves the capacities of society to design, build, and maintain in this arid geographical space through creating techniques, skills, and crafts of water catchment and distribution, protection of soils, recycling, and the optimal use of building materials and energy. It constitutes the historical knowledge of communities (Martin 1908).

Dense Fabric

Kesar of Timimoune is a compacted fabric that forms an urban unit connected yet separated that overshadow each other, reducing heat loss and, therefore, energy consumption.

Biodiversity

Kesar contains green and blue spaces (palm oases), which creates room for biodiversity and provides a natural space for residents, visitors, birds, wildlife, and plants. The houses also contain special spaces for raising pets such as livestock, poultry, etc. Which has a direct relationship with palm oases.

Microclimate

Green and blue surfaces (oases) that constitute between 50% to 60% of the traditional fabric area contribute to creating a livable microclimate compared to the arid and harsh climate of the region.

Energy Use Efficiency

The design of the buildings inside Kesar contributes to relying heavily on natural lighting and ventilation by creating patios (open space 1/3 of the surface) and introverted facades inside the houses, sequence streets (lighting-shadow), and twisted street system, in addition to construction materials (earthen materials) that largely contributes to energy conservation.

Construction Techniques and Materials

The residents of Kesar Timimoune relied on earthen architecture, specifically adobe architecture, which is characterized by its environmental characteristics (good thermal insulation, low energy consumption in the production phase, endless recycling) (UNESCO, 2009–2014) in addition to its local availability.

Social Contet

Mixed Land Use

Kesar is a dense fabric composed of several Kasbahs that expanded over time to form separate tissues, each of which has its mosque and public spaces, they are all connected via a street (El-Manjour) that extends from the beginning of Kesar to its end (Fig. 8).

Fig. 8. Roads and public spaces of the Kesar of Timimoune source: author.

The Kesar achieve a mix of land uses (commercial, habitat, equipment, leisure activity) that help keep the city compact and improve sustainability and social cohesion.

Social Inclusive Design

The public spaces of Kesar Timimoune are characterized by a hierarchical system (public, semi-public, private) depending on the nature of the agglomeration (urban, housing group, house); these spaces also differ by function, gender, and age group depending on the social and religious beliefs of the Kesar residents. Public spaces, through their design, ensure cohesion and social solidarity (Israa Hanafi, 2016).

Security

Kesar of Timimoune has a high level of security due to the hierarchy of streets and public places and good social cohesion throughout the Kesar. Additionally, the Kesar design forms a dense unit with defined entrances and exits.

Walkable Street and Accessibility

The streets inside Kesar reflect the nature of the conservative society and the arid environment, and this is evident through the following design principles used:

• Half-covered Street system: This system relies on sequential opening and covering of the street, which provides adequate natural lighting that preserves privacy. It also allows air circulation in shaded areas, providing a cool breeze in periods of high temperature and warmth in times of cold.
• Twisted Street System: Analysis suggests that the twisted streets are the result of the topological nature, but this morphological shape contributes as a basic factor to reducing the wind speed through breaking the direction of the wind and moderating its temperature in different seasons. Through analysis of the ground, we can see that most streets in the old urban fabric do not exceed 3 m/s air velocity, which is a good speed to moderate the climate.
• Walkable Street and accessibility: The streets in the Kesar are all connected to the main street in a hierarchical manner (public streets, semi-public streets, and impasse). To preserve privacy, which is considered one of the values of this Muslim community.

Economic Context: Local Agriculture and Food Production

The oases provide seasonal produce of vegetables and grains, which are stored to provide food throughout the year, as well as dates in significant quantities, which were considered the staple meal, in addition to their use in the past for barter against other unavailable products.

In the past, the Kesar of Timimoune was a refuge for many local economic activities, such as agriculture, industry, and trade, in addition to cultural activities. Currently, economic activities are limited to traditional agriculture and some traditional crafts.

Conclusion

Kesour (plural of Kesar) is considered the first form of construction in the Algerian desert. For many decades, their inhabitants were able to live in them despite the harshness of their arid environment by creating a special ecosystem (oases). To understand this complex environment, a morphological analysis is carried out based on the decomposition of the urban form of Kesar Timimoune into four systems: plot system, road system, built system, and open space system.

The results show the design principles used in this traditional settlement, which in turn were used in the matrix analysis of the Kesar to highlight sustainable qualities of the traditional settlement of Timimoune city, as lessons from which many principles and references can be extracted for designing modern sustainable cities in arid environments (Basiago, 1996), among the most important of these principles:

1. Environmental Sustainability Deep knowledge of the arid environment and the climatic factors related to it is one of the most important foundations of design while respecting the proportions of green spaces and their location and designing buildings that are in harmony with their environment, relying in particular on local materials, which helps in reducing the temperature and creating dense shade areas.
2. Social Sustainability The design of Kesar Timimoune, with all its spaces and details, is the result of accumulated experiences through which residents were able to translate their needs and adapt the design to these needs, values, and social principles, which create affiliation, social cohesion, and security, and therefore social sustainability.
3. Economic Sustainability For decades, the residents of the Kesar were able to achieve self-sufficiency by providing basic needs. The oases were considered the main source of food, in addition to the underground water that they were able to extract and preserve in ingenious ways. They also relied on local materials in industry and construction; all this has closely contributed to the achievement of sustainable economic development.