Sciences & Technologie D is a biannual journal which publishes original scientific articles in three languages: French, English and Arabic in the following disciplines: Architecture and earth sciences.
The provisions of Islamic architecture through reading in the books of the first and contemporary times.
The interest in studying the Islamic architecture which has fundamentally begun in modern era.Arab and Muslim researchers, however, were not interested in the matter until the middle of the last century. They dealt with the subject relying on a descriptive approach which determined its concepts and decorative architectural elements. In most cases, they studied them in isolation from their environment or surroundings, which represent the urban centre.Besides, Arabs and Muslims didn’t relate their work with legislative, social and intellectual aspects which may help in understanding the urban community.In the 1990’s, however, the approach of highlighting the role and the impact of legislation in forming the urban environment in Islamic cities developed. Such approach led to the appearance of some books written by Arab researchers, these sources relied on books and manuscripts from the early time which followed the appearance of Islam exactly the second century A.H. Our study comes in the interest of books that dealt with the method of highlighting the role and impact of legislation in shaping the urban environment of the Islamic cities from the first and the second ages mentioned above. This environment went in the line with the structure approved by the scholars of the book, the Quran and the Sunnah. Those books were translated and written by the writers of the first age to be used and exploited by the writers of the contemporary age.In this regard, legislation as a highly regulated form for the system represents a wealth of a great benefit especially for the Islamic society. The books of the first age studied and analysed this problematic of the development of laws, in addition to the social and customary laws and their development leads us to follow the movement of the development of our cities. Because the legislations and laws start from and end to the architectural movement and the subsequent development of urban and civilisation, through reading and devising the books of the two times together and to highlight the relationship between them, if any.
SOCIAL EFFECTS OF THE REGULATION OF MAJOR EVENTS
Regulation is a set of measures and indications governing a particular field or subject in the form of legal texts. The various sectors of the city are subject to regulations that control all the activities and actions carried out by the citizen and the authorities in this city. Any fact, social, economic, environmental or other, is a result of several factors that bring together man, his environment and the framework that manages this relationship between the two. This group is flexible because man and his environment are dynamic factors that are exposed to permanent changes because of their evolution. This can lead to a control and simulation of any results to be exercised on any of these factors. The effects of regulations on "city-citizen" is a result of the practice of texts and regulatory articles, they can be a powerful element to have positive actions on the city and its citizen, especially in the presence of ephemeral factors that boost the dynamism of different sectors, such as events. The organization of major events is an opportunity to implement various regulatory texts and to focus on the city-citizen relationship, since the event stimulates and involves all the components of the city such as its social component.
CITIZEN PARTICIPATION AND COMMUNITY SPIRIT IN A PROJECT TO DEVELOP THE PERMANENT SAFEGUARD PLAN
The two old quarters of El Oued souf city "Messaaba and Acheche" having the status of protected sector since 2013, they have been given the elaboration of the permanent safeguard plan project. The citizen is a determining element in this project because he constitutes the element which brings this heritage to life. Therefore, citizen participation must be at the heart of the project process, the effectiveness of its participation depends on individual differences. These variables could be demographic, personality, or community spirit. The purpose of this article is to examine the level of community spirit which influences the participation process of the citizens concerned by the project for the development of the permanent safeguard plan, through a survey which was undertaken among the inhabitants of its two old quarters.
Le commerce est considéré comme l’un des plus importants des thèmes qui ont bé-néficié de nombreuses études et cela peut être expliqué par le rôle intéressant du commerce dans les villes. C’est pour cette raison que des nombreux concepts ce sont apparue d'étudier le commerce et sa relation avec l'espace, à l’image du cas de la centralité commerciale. La centralité commerciale est un phénomène que nous allons l’examiner en mettant en évidence l’une des villes algériennes, la ville de Sétif, en étudiant la ré-partition spatiale des activités commerciales dans cette ville pour la mise en évi-dence : les localisations sociales les plus attractives et leurs rôles dans la structura-tion de l’espace ou sa négligence.
El-Khroub City, between urban development and transformation
Algerian cities have undergone many transformations as a result of the industrialization policy of the 1970s and the phenomenon of rural displacement, which has had a significant impact on the acceleration of urban growth, the swell of city sizes and the doubling of their population, and these rapid transformations in various areas have resulted in the growth and development of society with the need and mandatory meeting of the requirements of the population at all levels. The city of Constantine explains well the elements of this transformation, because of its poor position and the expiry of its real estate reserves, its local authorities were forced to look for a place capable of absorbing its growth.
AMBIVALENCE OF IDENTITY AND RECURRING URBAN PLANNING CRISIS.
In this article we present a study based on an investigation and led with lecturers of the Faculty of Architecture and Town planning of the University Constantine 3. Its objective is to report the opinion and the value of judgment which lectures concerning the town planning as taught discipline, job/profession and field of knowledge. The approached items in the questionnaire are the ones dealing with town planning (concept of town planning, methodological problem, urbanistic balance sheet) on the form of urbanization.
THE NEW TOWN ALI MENDJELI IN CONSTANTINE
The world knows a brutal urban explosion. Each country has been endeavored to react in its own way, its capacities, its policy, its social situation... Creating housing environment with reduced accommodation, large ensembles, cities, self-built, suburban, satellite cities, new towns... Constantine metropolis of eastern Algeria saw its peripheral villages transformed into satellite cities: Khroub, Hamma Bouziane, Didouche Mourad and Ain Smara. Faced with this situation, the public authorities considered it useful to plan a new urban set: the new town of “Ali Mendjeli”. How evolved this city?
The city of Tebessa is currently presented as a mosaic city, in which can be distinguished a set of fragments of cities socially and morphologically differentiated: Abandoned old fabrics, large uncontrolled complexes, more generally new urban peripheries are worrying and constitute scrambled landscapes of the city. These serious consequences affect us every day, the task is enormous. It consists in particular of creating a dynamic management of the reality of this city. So how can we manage these urban realities and respond to the concern for the sustainable urban development of the city of Tebessa? This new vision, around which are mobilized academics, professionals and which is the subject of a national problem. It will aim the search for a new coherence between society, economy, space and culture, based on a real and sustainable development. This article develops an illustrative case of a heritage city, is the desire to enhance the urban and architectural context and continue its history, and in the respect of the environment.
ROAD ACCESSIBILITY ELEMENT STRUCTURING THE URBAN SPACE
The main purpose of this study is to highlight the level of accessibility in the urban community similar to that of small urban centers. The field study showed that access to these cities is closely related to the levels and quality of the roads that lead them. Access is easy in the northern parts of the country, where the road network is dense, but in the mountainous and desert areas, lacking a dense road network, access is limited.
METHODOLOGICAL STUDY OF URBAN GROWTH IN ALGERIA.
The urban sprawl is considered as an important key factor in the spatial planning, because it goes against a definite number of main values of sustainable development. Certainly, this phenomenon of spatial extension show several spatial, economic, social, environmental and even visual problems, which are strongly criticized by the actors of sustainable development. At the same time, the cities continue their drastic spreading in order to meet their needs. In this frame, in order to be able to plan our cities efficiently and sustainably in the future, it will be necessary to understand this phenomenon and, to have a serious reflection on the future of those cities and their evolution. Through this paper, the present study consists in characterizing and measuring the urban sprawl of the city of Batna and predicting its future sprawl. To this end, it will be necessary to apply a mathematical model, which is based on the exploitation of survey maps and satellite data of the region, and then extracting the rates of the built surfaces according to the distance from the historic center of the city in concentric halos.
ANALYSIS OF THE FLOW-SUSPENDED MATERIAL RELATIONSHIP DURING THE FLOODS IN THE OUED ISSER WATERSHED.
This work focuses on the study of the relationship between suspended sediment concentration C and liquid flow Q during floods, on one hand, and the quantification of sedimentary flow in the watershed of the Isser wadi, on the other hand. The analysis of 84 floods over a 30-years period (1971/2001) shows a seasonal dynamic of suspended sediment availability, which increases in summer (especially in August) and autumn and decreases in winter and spring when flow is high. An analysis of the events recorded on the Isser wadi is made from the appearance of the graphs representing C as a function of Q which draws four hysteresis models hourly, counterclockwise, linear plus loop and figure in eight. The total flood performance in terms of suspended solid transport is 5.07* 106 tonnes, which corresponds to a specific degradation of 1222 t.km-2.year-1. Suspended solid flux varies considerably from one flood to another depending on many factors such as seasonality and flood duration, and hourly and counterclockwise floods are the most frequent and produce 70% of total sediments. The analysis of seasonal yields has shown that winter contributes a great deal of sediment (49%).
CRITICAL ANALYSIS OF A MOUNTAIN AREA DEVELOPMENT PROJECT
The development of the mountain in the context of tourism activities, is a phenomenon of international significance supported by the World Tourism Organization (OMT). In this perspective, Algeria has taken organisational legislative measures in favour of the starting of tourism in each physical zone, amongst other things the impoverished and marginalized mountainous rural zones. This experiment wants to be voluntarist and pioneer in one of the commune of the wilaya of Mila; it is about the mountainous region of Tessala Lamtai. This article is based on the diagnosis and analysis of a technical study relating to a project of a climatic station which is still in its initial stage.
PENURIE ET CONFLIT D’EAU PENDANT LA PERIODE COLONIALE
La ville de Constantine durant la période coloniale a connu de longue période de sécheresse en particulier celle de 1881/1882. Pour remédier à ce problème crucial qui est celui de l’eau, source aussi de grands conflits quant à sa répartition et sa distribution entre les divers acteurs de l’époque. Les autorités militaires de l’époque ont pris plusieurs dispositions d pour mettre fin à ce problème. La satisfaction des besoins se faisait difficilement dans un contexte de conflits spatiaux et sectoriels. La coexistence de gros ensembles consommateurs d’eau engendraient un déficit crucial dans la ville de Constantine. Une meilleure gestion et une distribution mieux étudiée s’imposait pour gérer au mieux ce problème de pénurie structurelle.
ديناميكية المراكز الثانوية في المجال الريفي وواقع تنميتها
Development process at the level of the studied secondary centers is revealed through the field reality the existence of a real development crisis their repercussions were socially economically and environment ally heavy, The most Important factors are due to the exodus rural that were not organized in the nineties weak credit provided under the municipal development, plans non-compliance with proposed urban programs and delays in the Implementation of planning schemes and other factors related to the local community. The reality of development requires reconsideration of the way the local governance and mobilizing efforts at the initiative of the participation of the active actors so as to promote secondary centers.
The national territory subject to flooding is disastrously presenting a major constraint for the economic and social development of the country. According to the census carried out by the civil protection services, one commune out of three (485 communes) is likely to be flooded in part or in full. These floods are the most frequent and destructive natural disasters, causing significant human and material damage. Prevention of these risks is of particular interest to the sustainable development of the country. In view of the increase in risk, only voluntary action seems appropriate, based on the recognition that taking into account flooding in land use planning and development can not be limited to an overly local, sectoral and short-term approach , But it presupposes a comprehensive policy for the prevention of natural hazards. A series of measures was therefore defined in July 2003, which led, inter alia, to the introduction of Law 04-20 of 25 December 2004 on disaster management in the context of sustainable development. The main contribution of this study is to identify the avenues for reflection that allow us to build on a solid scientific foundation for the construction of a city resilient to the risks of floods. The objectives of this research are to provide information on the level of resilience of the city to flood scenarios and to help the public authorities to make appropriate decisions Time to increase the level of resilience of urban areas and to show that other avenues deserve to be explored in order to overcome the current impasse expressed by the rising cost of damage.
MORPHOLOGICAL IDENTITY OF ZIYANIDE MINARETS
The purpose of this study is to identify, through a morphological analysis, the structure of the Zyanide’s minaret, and build an architectural database reflecting the intrinsic characteristics of such proprietary to the Islamic architecture. The Zianide kingdom has been a hub to several civilizations that influenced the evolution of the its urban space. For intence, the city of Tlemcen, was not just the capital of the kingdom but the ground expressing all the previous civilizations. The question is : what was the impact of these successive civilizations on the artistic creation of Zyanide minaret ? Indeed, this method tools allow a clear description of the structuring of the studied object and the layout of its architectural treatment. It is a result of the structural method where the founding are relative to the nominal identity of the objects, and it allows us to identify the fundamental structure of the Ziyanide Minaret. In this paper, we have shown our preliminary results as part of our PhD thesis.
THE BORDER CITY BETWEEN REALITY AND ILLUSION:
Undertaking a reflection on a city that has lived for a long time on the periphery in relation to its national territory is not an easy thing. It requires us to associate two spatial objects that are: "the city" and "the border". This association glimpses realities and ideas that are sometimes original and seem a priori difficult to grasp. In this regard, the objective of our article is to understand the relationship between the city of Tebessa and the border. And this, through a historical analysis of two essential elements namely: the border position and the road layout. Throughout this intervention, we will try to show that the mutation of the border, from a "moving zonal" form to a "fixed linear" form, has probably had repercussions on the city of Tébessa. antique Theveste, moves from a border march where, she played the role of a hub, to a margin city, which is closed on itself. Given this correlation, the border can be a key element for the city of Tebessa. It can also offer him the opportunity to register in the long term as a city "cross-border metropolis" of tomorrow.
ESTIMATION DU TRANSPORT SOLIDE ET EVOLUTION DE LA RELATION « DEBIT LIQUIDE- DEBIT SOLIDE » DANS UN BASSIN SEMI-ARIDE.
The extent of erosion and solid transport in the catchment areas of semi-arid Mediterranean areas has attracted the interest of a large number of researchers, who have multiplied studies over the past decade to understand and explain the mechanisms, their causes and consequences. Hydrological measurements (liquid flows, average daily concentrations) were carried out over a 29-year period (1973/74-2001/02) in the watershed from the upstream Mellegue wadi to the Laouinet station by the Algiers A.N.R.H. services. The analysis of instantaneous data collected at the station between 1973 and 1985 showed the importance of the statistical relationship between liquid and solid flows (QL-QS) and the temporal (seasonal) understanding of hydrological phenomena in this basin. The suspended solid flows are correlated to the daily average liquid flows and we were able to plot the solid transport curve which gives a regression of the power type QS = b QL^a. The seasonal and daily scale is very representative of the phenomenon of solid transport. The results obtained by applying this model are very encouraging because the correlation coefficients between annual and seasonal liquid and solid flows vary between 0.85 and 0.95. The maximum values of solid inputs recorded during the spring season exceed other seasons. This variability is explained by the physical characteristics of the environment (soil condition, vegetation cover), the aggressive nature of spring rains, where the maximum annual PJ for May reaches 75 mm of rain/day. The average interannual solid input to the catchment outlet is estimated at 570512.7 tonnes/year, with a specific solid transport of 161 tonnes/km2/year. This value remains relatively low compared to those observed for other basins with similar hydrological regimes.
The spatial mobility between supply and demand, attempt to evaluate
The urban economic and social development are the most important factors which have led to the increase mobility. This has given rise to a spatial mobility and a provincial dynamism which influence directly the demand for transport and balancing it with supply. Through the study of the movement of the urban population of Annaba and their use of collective transport means, we evaluate the supply and demand to balance the organization of transport in the city. The urban agglomeration of Annaba is at its extreme mobility like that in large gatherings in Algeria. Hence, we focus in this research on evaluating and analyzing the supply and demand for public transport on buses inside the urban agglomeration through a field study that consists of a questionnaire. This study aims at finding the causes wich control supply and demand and also the difference between them. Besides that, we try to determine the strategies (methods)to balance between them.
Copyright (c) 2020 Sciences & Technology D, Earth Sciences
In Algeria, the correlation of health and environment is always mediated by a question on the deterioration of the living environment and the pollution. The latter has reached alarming proportions, in particular, cities like Annaba, one of our industrial cities. This city is home industrial units causing pollution which adverse effects are well known by its inhabitants, the main victims of this situation. In order to contribute to the debate on this issue, this article will attempt to analyze industrial pollution while identifying other sources and their effect on the natural environment and public health; and secondly to define the most effective methods to mitigate problems, knowing that Algeria has issued a legal arsenal of the most important in the context of sustainable development and the fight against pollution.
THE IDENTITY OF THE CITY OF JIJEL AND ITS DEVELOPMENT BETWEEN PERCEPTIONS AND EXPECTATIONS OF ITS INHABITANTS
The two concepts "requalification" and "identity" of the city constitute the backbone of this article, which is a part of our doctoral work. Those two notions will be discussed in the context of the city of Jijel (Algeria). This city, like the other Algerian cities, is currently suffering from plural dysfunctions that it has experienced throughout its urbanization process. In this actual situation, how can the use of urban re-qualification operations revive this city and respond to the needs and expectations of its population? We assume that the success of any re-qualification operation is based on the involvement of the citizen. This research is a qualitative study, based mainly on a careful listening to the citizens of Jijel about their expectations of any intervention on their city. The semantic analysis of the results enabled us to identify the Jijel citizen’s views of their city, also it shows us the causes and consequences of the disqualification phenomenon in their city, and examines the changes that it has made through time; are they essentially linked to their practices and use? Or do they explain it otherwise? Such questioning informs us about the key elements that should be integrated in any requalification operation.
THE RAIN - FLOW RELATIONSHIP IN A MEDITERRANEAN SEMI-ARID HYDRO SYSTEM
The variability of input (rainfall) and output (flow) signal in the Oued Endja watershed (affluent of the oued Kebir-Rhumel), upstream of the Beni Haroun dam, is studied using hydro-rainfall monthly data, available in a period of 30 years (from 1973/1974 to 2004/2005). The annual reduced centered index is a powerful parameter to use in order to distinguish extreme periods (wet and dry cycles). also, due to the use of spectral methods including wavelet and its coherence, it possible to show that the evolution of the rain and the flows is structured according to several modes of variability, which concerns various temporal scales. The spectrum of coherence (flow/rainfall) indicates a strong variability and shows a significant connection for the various scales of time. The frequency band of one year is marked by the strongest rates of coherence (96 % calculated for the flows of Douar Tassadane gauging station and the average rainfall on the catchment area). Moreover, the band (2-4) years is marked by a rate of 81 % (evaluated for the flows of KoudiatTendart station and the average rainfall on the catchment area).
PLUVIOMETRIC TREND AND VARIABILITY IN A SEMI-ARID REGION
The purpose of this article is to evaluate the rainfall trend in a semiarid watershed case of Timgad, which relies on the calculation of the SPI (Standardized Precipitation Index), the chronological graphical treatment method of the information (MGCTI) and breakage indices. These trends have been proposed over a period of more than forty years of measurement and for six stations of the Algerian rainfall network. Statistical methods have shown the severe and lasting nature of the climatic drought observed in this region from the end of the nineteen seventies and it also highlights, the return to the wet phase from the beginning of the years two thousand.
During last three decades, Algeria is known for a huge and ambitious program in constructing of dams. Climatically, East Algeria is of the most abundant rainfall in the territory, where 25 dams are recently in operation, distributed through watersheds, with very contrasting physical characters. Monthly and annual regularization balances are studied using data from the National Agency for Dams and Transfers (A.N.B.T) which is available on ten dams in a period of 23 years (from September 1990 to August 2013). Difference between the average annual regulated volume (21.13 hm³) and theoretical regulated volume (37.72 hm³) shows an importance deficit in the water supply system, which is strongly related to the frequency of wet and dry years. A chronological graphic method, with a statistical approach in data processing (type "Bertin matrix"), is applied for three principal parameters (input, rainfall and rate of filling). The result indicates a strong relationship between the parameters studied: a clear growth from the dry years from September 1990 until August 2002, and vice versa for wet years from 2003.
DÉSENCLAVEMENT ET ATTRACTIVITÉ DU TERRITOIRE DE JIJEL : RÔLE ET IMPACTS DU PORT DE DJEN DJEN.
Le port de Djen Djen est considéré comme le plus important ouvrage portuaire en Méditerranée, en termes d’espaces et eau profonde. Hub international et Pôle d’attractivité, en projet pour la wilaya de Jijel, ce port pourrait-il constituer un important moteur pour le développement du territoire ? Actuellement son impact est encore faible en matière de croissance économique de la région. Pour élucider cette problématique et comprendre pourquoi la wilaya de Jijel, disposant d’un tel port n’arrive pas à se hisser sur le plan économique, nous utiliserons une démarche déductive et pluridisciplinaire. Deux hypothèses semblent expliquer la situation: la première consiste en l'enclavement physique de la wilaya, la deuxième s’articule autour d’une stratégie de développement capable d’anticiper le devenir du port par deux axes majeurs, qui sont :la création d’une synergie entre ce dernier et le complexe sidérurgique de Bellara et la réalisation d’un terminal à conteneurs, à travers lequel, le port de Djen Djen deviendra une porte sur la méditerranée pour les pays du sahel via la transsaharienne.
Copyright (c) 2017 Sciences & Technologie D
التعمير الصغير وآليات التحول إلى أطراف مدينة باتنة
أخذت التوسعات نحو المراكز الريفية شكل انتشار المد الحضري في الوسط الريفي، حيث عرفت هذه الأخيرة في المناطق الفاصلة بين مدينة باتنة ومراكز الأطرافتحولات جذرية ,ترجمت بتطور الاستخدام السكني, بفضل سهولة الحصول على قطع أرضية للبناء تعود ملكيتها للخواص، وأيضَا ذات صفة عقارية تابعة للعرش. الارتكاز على الأطراف في تخطيط نمو مدينة باتنة أفرز تحولات جذرية وعميقة في المراكزالتي كان يغلب عليها الطابع الريفي بدخول أنماط وعناصر الحياة الحضرية فيها، وهذا التحول العفوي أحيانًا والإرادي أحيانًا أخرى. أدى إلى توافد سكان جدد بأعداد كبيرة من مدينة باتنة بالإضافة إلى تطور الأنشطة الاقتصادية الغير فلاحية كالصناعة والتجارة والخدمات أدى إلى بروز العديد من التناقضات والصراعات بين البيئة الريفية والتعمير الطوفاني.
Copyright (c) 2019 Sciences & Technologie D
إشكالية النمو الحضري في الجزائر بين الواقع والأفاق - حالة مدينة العلمة "ولاية سطيف"
تعتبر إشكالية النمو الحضري في الجزائر ظاهرة معقدة وشائكة أصبحت مع مرور الزمن هاجسا يهدد تناسق وانسجام الأنسجة الحضرية للمدن الجزائرية عامة ولمدينة العلمة على وجه الخصوص حيث شهدت هذه الأخيرة نموا حضريا سريعا كحالة عن المدن الجزائرية منذ الاستقلال، وكان ذلك من خلال تزايد عدد السكان والمساكن وتطور المساحة العمرانية بسبب تداخل مجموعة من العوامل في مقدمتها: أهمية الموقع الجغرافي ضمن مدن الشبكة الحضرية الجزائرية محليا وإقليميا ووطنيا والنشاط التجاري ونمط التخطيط الحضري الذي لا يتوافق مع خصوصياتها، ولقد جاء اختيار مدينة العلمة لتكون ميدانا للبحث بحكم الوزن الحضري والإشعاع الجهوي المتباين للاستثمار التجاري بشكل خاص باعتبارها قطبا عمرانيا واقتصاديا يتطلب اهتماما كبيرا من قبل جميع الأطراف والسلطات لمعالجة الإشكاليات القائمة في هذه المدينة مما جعلها وبامتياز المثال النموذجي الوطني للمدن الجزائرية من حيث مستوى التحديات التي ستقدمها في الأفاق. وعلى الرغم من صعوبة تحليل واقع النمو الحضري في مدينة العلمة إلا أن الأفاق والتوجهات المستقبلية للنهوض بالنمو الحضري تتمحور حول وضع مقاربة تنموية تقوم على أساس تحقيق الحوكمة الحضرية المبنية على الجانب التحليلي وسياسة عمرانية واضحة وأسس علمية ومنهجية ينتج عنها حالة توافق للنمو الحضري من جميع النواحي العمرانية.
L’ALIMENTATION EN EAU POTABLE DANS LE GROUPEMENT URBAIN DE CONSTANTINE
Le Groupement Le Groupement Urbain de Constantine est composé de cinq communes, abritant 883882 habitants en 2015. Le volume d’approvisionnement en eau potable du Groupement a atteint 117 millions de m3 ; le volume facturé accuse, néanmoins, un déficit de 51% par rapport au volume d’eau distribué. Les données statistiques de la SEACO (année 2015) montrent que le nombre de fuites d’eau a connu une baisse relative, résultat des opérations de réhabilitation des réseaux des centres urbains. En parallèle, le renforcement de la fourniture en eau, à partir du système de transfert du barrage Béni Haroun, s’est traduit par une augmentation de la durée moyenne de desserte en eau potable (18,3 heures par jour). La répartition inégale dans l’approvisionnement en eau des agglomérations est imputable aussi bien aux disparités dans la disponibilité de la ressource qu’aux problèmes de gestion des infrastructures hydrauliques.
PLAN STRATEGIQUE DE DEVELOPPEMENT D’ALGER, POUR UN RENOUVELLEMENT DE LA DEMARCHE D’APPROCHE DE LA VILLE ALGERIENNE.
La question du renouveau des logiques de la production urbaine est à l’ordre du jour. Elle revoie à l’émergence de nouveaux enjeux, processus, acteurs, démarches et outils, témoins des mutations profondes qui touchent désormais le champ de l’urbain et qui réinterrogent l’efficacité du processus classique. L’objectif de cet article serait d’apporter des pistes d’interprétation sur le renouvellement des modalités d’approches en relation avec la pratique de planification du ‘’Plan Stratégique de Développement d’Alger à l’horizon 2029’’. Notre approche est fondée sur une approche historique du processus général de planification du plan, en adoptant une série d’entrevues auprès d’acteurs-clés dans la prise de décision politique et technique. Elle combine l’exploration, analyse de contenu et lecture des rapports de cohérence entre discours et démarche. Ceci nous a permis à la fois d’identifier le schéma méthodique des logiques d’actions adoptées et les mécanismes concrets qui structurent le processus général dans sa phase élaboration et définition et d’apprécier la nature, les formes et les limites de l’innovation inscrite dans le plan. L’analyse du plan révèle un nouveau mode de faire la ville algérienne en référence à la mutation de la conception du rôle des acteurs locaux, réorientant la culture de l’action publique vers des approches de projet, contre la logique de programme rigide présente dans la démarche traditionnelle de planification.
ESSAI D’ESTIMATION DE L’EROSION HYDRIQUE EN NAPPE, PAR RAVINEMENT ET PAR MOUVEMENTS DE MASSE A L’AIDE DES SIG ET DU MODELE USLE. L’EXEMPLE DU BASSIN VERSANT DE LA SOUMMAM (NORD-EST ALGERIEN).
Les apports solides annuels moyens de la Soummam à la station de Sidi Aiche (série 1954/1992) est de 4,3.106 tonnes. Cette valeur globale obtenue à l’embouchure ne permet aucune localisation de zone d’apport. Afin d’estimer l’impact des aménagements (4 barrage) réalisé dans le bassin et prévoir l’impact des futurs aménagements, la spatialisation de l’érosion hydrique s’impose. Pour atteindre cet objectif, nous avons utilisé l’équation universelle. Les pertes en terre dues à l’érosion en nappe n’atteignent que 48% de l’apport solide mesuré à la station de Sidi Aiche. De ce fait, nous avons ajouté l’apport du ravinement et des mouvements de masse en se basant sur une cartographie des facteurs à l’origine de ces formes d’érosion. L’addition des pertes en terre relatives à chaque forme d’érosion en l’occurrence 2,01.106 tonnes pour l’érosion en nappe, 1,67.106 tonne pour le ravinement et 1,19.106 tonne pour les mouvements de masse atteint le tonnage de l’apport solide naturel enregistré à la station de Sidi Aiche (4,88.106t/an). Ainsi, cette démarche généralise les pertes en terre à toutes les formes d’érosion hydrique et compense par là-même la faiblesse de l’USLE. Néanmoins, pour obtenir une validation définitive, ces résultats encourageants nécessitent l’application de cette démarche sur d’autres sous bassins jaugés.