Historical Paths and the Growth of Baghdad Old Center

: Urban growth of cities is connected with three related problems, the first one, is the deterioration of the center, which is a mark for historical origin. The second is the emergence of city edge, which contradicts by the center. The third one is the rapid semi urbanism of the edge. Literature review showed that Baghdad historical center (Old Rusafa and Karkh) had grown in four morphological stages, during which main paths had been changed from those which were perpendicular to the river front to those parallel to it. Research problem is that “there is a knowledge gap about the direction and origin of paths within Baghdad old center, after its growth”. The first research hypothesis is, “the direction of paths within old Baghdad center had been changed from those perpendicular to the river to parallel to it, then to a grid system by the effect of streets cut through and bridges constructions”. The second research hypothesis is that, “New paths (streets) which had been cut through old center had an origin within the historical paths”. The research aims to verify from the change in paths direction within old center, also from the origin of new streets in relation with historical paths. Research found that some new streets within Old Rusafa and Karkh, which are parallel to the river, existed as historical paths, according to the integration genotype of this center within the four morphological stages.


1-INTRODUCTION:
This paper studies the historical paths in Old Baghdad Center (Old Rusafa and Karkh) through its four morphological stages. The paper ascertain that there are historical paths parallel to the river in addition to Al-Kaelani origin-Al-Maidan, and Al-Maidan -Al -Mustansir streets, those paths are basic for the origin of new roads in Old Rusafa and Karkh. The research problem is that "there is a knowledge gap about the direction and origin of paths within Baghdad old center, after its growth". The aim of this paper is to prove that. First research hypothesis as, "the direction of paths within old Baghdad center had been changed from those perpendicular to the river to parallel to it, then to a grid system by the effect of streets cut through and bridges constructions". And the second research hypothesis can be stated as, "New paths (streets) which had been cut through old center had an origin within the historical paths". So the research methodology will be: -Meaning of urban growth and path.
-Theoretical study to Old Baghdad Center, and its paths.
-Analytical study of Old Rusafa and Karkh using geographical information system.
-Findings, conclusions and recommendations.

2-URBAN GROWTH:
Growth means increase over time. This increase may be physical or abstract, so the system will be more complicated (www.wikepedia, the free encyclopedia.org/wiki. Growth/html).
Urban growth means physical expansion.
This means spatial and functional changes, and transformation from unbuilt area to urban area.
This later means changes in land use, so activities and spaces are basic elements to a system known as urban growth (Cheng). As a result urban growth has an implicit meaning, known as urban sprawl. The dynamics of urban growth of a city starts from the continuity of urban sprawl, to change the vacant land to urban land, for the purpose of development (Batty).
Urban growth of cities is connected with three problems related together. The first one, is the deterioration of the center, which is a mark for historical origin. The second is the emergence of city edge, which contradicts by the center. The third problem is the rapid semi urbanism of the edge (Batty).
Rapid growth means constant turmoil, facilities which are ill fitted to demand, and institutions whose capabilities constantly lag behind the need for them (Lynch, 1982).
Generally, the growth in size of a place or a change in its function can often be too rapid for successful agreement and adaptation of the vitality and fit. While growth was once applauded, and still is in economics, we have recently come to see dangers in it, and some argue for "zero growth", just as Plato did, but it is hard to maintain the absolute stability. Zero growth is potential of Journal of Engineering Volume 19 September 2013 Number 9 1075 decline and deterioration. Rapid decline (like rapid growth) may be a catastrophe. Therefore, in certain general situations, there might be optimal rates of growth or decline (Lynch, 1982).
The concept of an optimum rate of change is as elusive as optimum size itself. The "goodness" of a change may depend more on its form than on its quantitative rate: was it an abrupt leap succeeded by recession, a wild oscillation, a continued unending expansion, or an s-curve of growth from one phase to another Repeated oscillation, for example, may give rise to standard difficulties. Or the form and extent of the change must be considered together. Yet even the effect of simple rate on our dimensions is still to be investigated. In general, the growth of the urban fabric and its decline, considered as the essential

2-1 Types of Urban Growth:
The most difficulties in analysing urban growth pattern by typology include how to quantify and characterize urban growth category (Shi, et al., 2012). From the potential of typology.
Forman (1995) divided urban growth into three types: infilling, edge-expansion, and outlying, other patterns of urban growth can be regarded as variants or hybrids of these three basic types. An infilling type refers to the one that the gap (or hole) between old patches or within an old patch is filled with a newly developed urban patches (Liu, et al., 2010) (Fig. 2a). An edge-expansion, also called urban fringe development, refers to newly developed urban patches spreading out from the edge of existing urban patches (Xu et al., 2007) (Fig. 2b). If the newly grown patch is found isolated from the old, then it would be defined as an outlying type (Fig. 2c). (Liu, et al., 2010;Xu et al., 2007).
The pattern of urban growth described as a 'diffusion-coalescence' phase transition. An edge-expansion was the most common growth type, while the spontaneous growth took a greater proportion in area and patch number than the infilling growth at the early stage, but its dominance reduced as urbanization proceeded from the diffusion phase to the coalescence phase The geometric attributes as well as spatial distribution vary among the different growth types, and more importantly, development direction and speed may be different (Xu, et al. 2007).

3-2 Old Karkh:
Al Karkh is an ancient village sited on the western side of Tigris River. In (157)

4-THE GREAT WALL OF OLD
BAGHDAD:

4-1 The great wall on the eastern side of the city:
In 517 AH (1123 AD), Khalifa Al Mustarshid billah decided to build a wall on the eastern side of the Baghdad city. The wall had four gates; first one was (Al-Bab Al-A'la), which was known as "Bab Al-Sultan" and later known as "Bab Al-Muadham". The second one was, "Bab Al-Dhafaria" which was located next to Al-Dharafia neighbourhood east of Baghdad, later known as "Bab Al-Wastani". The Third gate was , "Bab Al-Halaba", later known as "Bab Al-Talasim". Lastly "Bab Al-Basalea", later known as "Bab Kelwatha" which was located next to

CENTURY:
In the late nineteenth century and after Medhat Pasha became the Wali (or provincial governor) of Baghdad in (1869) where the city was surrounded by wall, and its gates for both Old Rusafa and Karkh (Fig. 3).
-Second morphological stage: This stage presents the growth and urban expansion of old urban fabric until the beginning of twentieth century (1908 AD) where part of the wall had been demolished (Fig. 4).

7-PATHS:
Paths are the channels along which the observer customarily, occasionally or potentially moves. They may be streets, walkways, transit  (Lynch, 1960).
Each path has its own character. It fits into the cultural and natural landscape in its own way and reveals its own sequence of views (Lynch, 1984).

7-1 Formative type-composition form:
This type is composed of individual buildings arranged together on the surface of a two-dimensional, and, clustered together on foundations of conventional configuration. In this type spatial coherence is embedded more than declared .Configuration elements are often stable and formal in shape. Visual paths are obvious and dominant on the quality of division sectors, kept every part of its independence, similar to functionalist pattern, which represents one of the modalities of formative type (Trancik, 1986).

7-2 Mega type-mega form:
Components of this type overlap together -Associative relation is super imposed within total form of urban form.

7-3 Group form:
This type is generated from a pool of independent parts are often similar. Associative

9-MEASURMENT:
The research used the geographical within their four morphological stages mentioned before, where genotype means, the basic generator which produces different special urban shapes (phenotypes). In language, it is the opposition to the deep structure (Hillier, 1996), also it means the social logic behind the configuration of urban settlements (Hillier, 1986(Hillier, -1987. Hillier mention that there are four main integrated genotypes (Hillier, 1983): -Globally integrated core, where the most integrated spaces connect the center to the outside, forming a wheel-like pattern. The most segregated spaces form clusters which are at the interstices of the wheel ( Fig. 9-a) -Urban area where the most integrated spaces distributed around the edges and do not penetrate to the areas geometrical heart.
Conversely the most segregated spaces form an inaccessible core at the center ( Fig. 9-b).
-Area where the integrated core is tightly wrapped around the center, creating an inward -looking integrated heart, which is accessible from outside, The segregated spaces form a band around the edge of the area (Fig. 9-c).
-An area which has an integrated core that forms a tree-like pattern across the town -thus linking the center to the outside -but leaving two large zones of inaccessible segregated spaces on either side of the integrated core ( Fig. 9-d).

10-PRACTICAL STUDY:
The practical study is a morphological analysis of Old Rusafa and Karkh within their four morphological stages mentioned before. The aim of this analysis is to discover the integrated 1083 stage, was found as a segregated path, with an integration value (2.611). It is the same path that connects, the area with Bab Al-Kadimain.
-There was an integrated path perpendicular to the river, which connect Old Karkh with Old Rusafa, across the river, which is known latter on as Al-Shuhada Bridge with an integrated value (0.8104).
-The genotype of this morphological stage is tightly wrapped around a center. -The genotype of this stage is a tree-linked pattern and it is parallel to the river.

12-1 General conclusions:
1-Growth of old Baghdad center was the reason for new streets which had cut through it.
Litreture review showed that these new streets tore the existing fabric. This paper verifies that some of these new paths (streets) had an origin within this center.
2-The growth of old Rusafa was s-curve. While growth of old Karkh was a repeated oscillation, where the form and magnitude of change have been linked together.

13-RECOMMENDATIONS:
-This paper recommends to consider these streets (paths) which had been cut through old Baghdad center, as historical paths as they have been constructed befor (50-100 years).
Also to consider the paths that connected Rusafa and Karkh across the river, as historical paths for the same reason mentioned above, even though the bridges are more recent.
-This paper recommends re-connecting these streets (paths) with existing fabric and the river to revitalize the historical center.