A proposal for the restoration of the Islamic Towers in the Segura de la Sierra Valley (Spain). Significance and values of this cultural landscape

1 INTRODUCTION Segura de la Sierra valley (Segura) is situated in the province of Jaén in the Southeast of Spain. In this valley there are still remains of a unique set of defensive structures built in rammed-earth in the High Middle Ages, making up and defining the cultural landscape of this natural area. These fortresses are placed in a triangular fashion, which eliminates any blind angles resulting from the abrupt topography. There are remains of twelve towers and there are historical accounts of other four, representing a magnificent heritage that is necessary to investigate, preserve and disseminate. These towers provide an indispensable record for the in-depth study of some of the formal, functional, typological and historical aspects of this kind of medieval military building. They also allow us to glean the criteria of territorial organization and construction technologies and their geometries or typologies that come from the al-Andalus building tradition in both Islamic and Christian periods (Fig. 1). An exhaustive analysis has been carried out on the towers of La Puerta de Segura (Segura valley entrance), Santa Catalina, Fuente de la Torre (Spring Tower), Gutamarta, Altamira, Espinareda and La Torre (The Tower). In others, such as Góntar, the North and South Santa Catalina’s watchtowers, Torre del Agua (Water Tower) and Cardete an in-depth study has been done of their morphologic, stratigraphic, functional and constructive features. This research and the knowledge obtained have enabled the demonstration of certain hypotheses related to the location of the towers in its territory, their construction and some functional aspects as their access system. A proposal for the restoration of the Islamic Towers in the Segura de la Sierra Valley (Spain). Significance and values of this cultural landscape S. Quesada-García School of Architecture,Malaga University, Spain L. J. García-Pulido Spanish Ministerio de Economía y Competitividad, Secretaría de Estado de Investigación, Desarrollo e Innovación, Laboratorio de Arqueología y Arquitectura de la Ciudad (LAAC), Escuela de Estudios Árabes (EEA), CSIC (Spanish High Council for Scientific Research), Granada, Spain doi: 10 14575/gl/rehab2014/036 ABSTRACT: Due to t he strategic position of Segura de la Sierra valley (Jaén, Spain) during the 12th and 13th centuries, there were built several defensive fortresses both by Muslims and Christians. As a result, there are still remains of a well-preserved medieval tower system using rammed-earth technology, with more than sixteen towers, often with a fortified enclosure, that represents a magnificent heritage. An exhaustive analysis has been carried out in order to do a scientific restoration of some of them. The research methodology has considered different phases in the stages that should be followed in the guardianship of a historical cultural asset: documentation/investigation, conservation/restoration and dissemination, with the development of a patent. The historical significance and cultural references of these towers with their territory, and the interest of the discoveries obtained due to the research made and the restoration project of some of them, are the principal contributions of this paper. 333 Chapter 1 Rehabilitation of historical sites, buildings and structures The research methodology has considered the documentation/investigation, the conservation/restoration and the diffusion. The documentation process derived from the compilation of the documentary and graphical published sources, as well as the photogrammetric survey of the Tower of Góntar, Torre del Agua, the North and South watchtowers of Santa Catalina and the Tower of the Castle of Cardete. That permitted the creation of accurate maps of these towers, while, at the same time, the territorial exploration enabled the creation of maps, showing the layout of these defensive structures in the valley. The phase of conservation and restoration has been limited to work on the Tower of Góntar, as well as the production of the restoration projects in the Torre del Agua and in the North and South Watchtowers of Santa Catalina. The methodological process for the transmission of this knowledge has been disseminated by means of papers and lectures in specialized symposiums, publications in scientific journals and in the web: www.santiagoquesada.com and http: // picasaweb.google.com/santiagoquesada.com.gontar. 2 THE DEFENSIVE STRUCTURES IN THE SEGURA VALLEY. THE CONSTRUCTION OF A CULTURAL LANDSCAPE Figure 1. Santa Catalina Plains with the situation of the three towers. Above: View towards Segura de la Sierra town. Below: View towards Puerta de Segura village, the natural entrance to this valley from the N orth and West. After the break-up of the Caliphate of Cordoba, this territory was a knjrah or territorial districts with its own autonomy. Segura was the main settlement, and different qarya-s and farmhouses surrounded it. There were also walled enclosures or cortijos (from Latin cohors-cohortis, Martínez, 1985: 9) linked to a tower that controlled the nearest cultivated areas. They fulfilled a dual productive and defensive function, and determined the economic and social development of this territory. 334 REHAB 2014 R. Amoêda, S. Lira & C. Pinheiro (eds.) After the conquest and during the first Christian occupation in the years following the battle of Navas de Tolosa (1212), Segura remained as the main town of a wide spatial area being lands over the present day Spanish provinces of Jaén, Albacete, Murcia and Granada. The control over the headwaters of the rivers Guadalimar, Guadalquivir, Segura, Taibilla and Tus and the rich forests of these mountains, gave to this territory an important mercantile value, due to the fact that it was the gate towards Castile of the goods produced in the Islamic kingdoms of Granada and Murcia. The gift of Segura town by the king of Castile included not only the castles, towers and farms, but other adjacent areas with the following productive units: lands, salt mines, vineyards, springs, rivers, mills, fisheries, meadows, pastures, holm oak and pine forests, pasture rights, tolls... The close relation between the castles and the towns and the pairing of church-castle, as an essential part of the social Christian organization, is one of the linking elements of the landscape. This is combined with the rural situation, as the network of husûn (plural of ۊi܈n, castles in al-Andalus that controlled and defended a territory and its inhabitants) that did not develop into cities. This rural continuity was the result of the Mudejar population remaining in the territory, while the Order of Santiago superimposed feudal structures of power and hierarchy on a spatial Islamic organization. In addition to their productive function, this set of towers and wall enclosures would have formed part of a defensive line constructed between the 12th and 13th centuries in the Levant Corridor. This was a natural route dating back to prehistoric times that connects the Guadalquivir with the east of the Iberian Peninsula (Eslava, 1989; Eslava, 1999). This set of walled enclosure, each with a tower, allowed for a rapid access from the qarya-s spread in the valley to a safe haven, as the urban walls and the Castle of Segura were too far away. These fortresses were usually built on the higher parts of the slopes, controlling from a wing a flat cultivated area of between 250 and 350 hectares. This settlement pattern is shown in the fortresses of Altamira, Gutamarta, Catena, La Torre, Cardete and Fuente de la Torre (Fig. 2). Figure 2. Segura valley with its mountainous and fluvial system. Situation of the castles, towers, walled enclosures and watchtowers in relation to the topography and the principal roads. Agricultural areas controlled by the fortified enclosures of this valley. 335 Chapter 1 Rehabilitation of historical sites, buildings and structures These small castles were strategically distributed, in a triangulated fashion and favored the maximum protection of the closest agricultural lands. In this way the valley kept a lookout, enabling also a connection with other territorial external zones to control the troop movement over Segura valley and its surroundings. 3 TYPOLOGICAL, CONSTRUCTION, MORPHOLOGIC AND FUNCTIONAL ANALYSIS OF THE TOWERS Almost all the Segura valley towers and walled enclosures have similar construction features using tabiya (rammed-earth), a building process that consisted of the construction of walls with tamped earth and lime using a refined technology that in Spanish was named as “tapia calicostrada”, “calicastrada” or “acerada” (Fig. 3). The mixture was composed of compacted and tamped earth and lime placed in layers inside the timber formwork or shuttering, called “tapiales” in Spanish. The size of each shuttering sheet was usually between 2.00 to 3.00 meters long and 0.75 to 0.90 m high, which could be managed by a single mason. Figure 3. A/ Sample of a reinforcing frame inside the rammed earth wall. B/ Original position of a reinforcing frame inside the rammed earth wall. C/ Non re-usable horizontal timber (70 x 30 mm) inside the rammed earth wall. D/ Cylindrical timber and other timber remains inside the low parts of the rammed earth lifts in the changes of section in the wall, found in each of the floors of the Tower of Góntar. These timbers work as hoops to tie the walls together. In time, the mixture of lime gravel and earth would become carbonated and turn into a stony material, as has been demonstrated from the chemical and physical results of tests done on the walls of Santa Catalina Watchtowers, the Tower of Góntar and Torre del Agua, with a resistance to simple compression between 29.00 Kp/cm2 and 51.13 Kp/cm2 a good density and a medium to low porosity. The granulometry results show that the mixture has been well prepared, which results in a good compactness. In these military buildings, the lower parts of the walls are built with perfect rows of rounded stones, with a diameter of between 15 and 18 cm and laid with a mortar very rich in lime and 336 REHAB 2014 R. Amoêda, S. Lira & C. Pinheiro (eds.) gravel. These stones disappear progressively as the height of the wall increases to be replaced with a concrete made of gravel, sand and lime. The walls of all of these towers have different sections. They are usually stepped internally and they start in their lower part about a vara and a half (approximately 1.10 m) wide, reducing progressively to the thickness of one vara (over 0.75 m). The narrowest towers, as in the examples of the North and South Santa Catalina Watchtowers, have a slope in three of their faces, with the fourth one practically vertical, which gives them a truncated pyramid shape. These slopes were constructed by putting an upper strut smaller than the lower one. The constructive quality of the towers of the Segura valley can be seen in their geometry, outline and modulation, in the way the putlog holes have been carefully shuttered with stones, in the rows of stones inserted into the plinth, in the lintel disposition in hollows and loopholes and in their structural conception, with additional timber in the narrower walls of each of the different floors, as in the Tower of Góntar. This timber reinforcement works like a wooden hoop and in some towers has prevented their collapse. The morphologic and typologic features of the defensive elements of the Segura valley are different, depending on their situation and function, and the age of their building. In the next paragraphs there is a detailed description of the military elements that have been restored or have a restoration project. 3.1 The Tower and walled enclosure of Góntar (UTM X: 0530808 Y: 4239209; Z: 1125 m.s.n.m) It is situated on the eastern lower slope of the promontory of the Castle of Segura close to the road that goes to Góntar village (in the current province of Albacete) and facing the hill of the same name. It is a fortified enclosure that would have been linked to the defensive system of the stronghold of Segura, but is independent from the castle ramparts (Fig. 4). Fi g ure 4. Architectonic surve y and façade anal y sis of the Towe r of Gónta r . This fortress was at the back of the castle in Islamic times, but at the front when the Order of Santiago controlled this territory. It would be linked to the control of the road that still exists going from Segura to Góntar. But this tower and walled enclosure were also situated on this spot to defend this weak flank from attackers on the hill of the same name which faces it. The remains of this fortress belong to a typology defined by a principal tower placed to one side of a walled enclosure, as a part of the actual fortified perimeter. It is 9 varas and 10 handspans in length and 6 varas in width (7.70 x 4.80 m, 1 vara in this tower=0,7984 m). There are no remains of battlements but the total height of the tower would have been around 15 varas (11.97 m), and the West and South walls are completely missing. The constructive quality of 337 Chapter 1 Rehabilitation of historical sites, buildings and structures This watchtower has lost its interior timber floor, but the rammed earth walls are almost completely preserved with their wider plinth at the foundation and steps that allow the decreasing thickness of the walls. The absence of remains of a waterproofing coat inside the tower shows that its lower spaces did not function as a cistern. The first floor might have been used as a granary, silo or storage of provisions and military equipment, and maybe also as a dungeon. 3.4 The South Santa Catalina Watchtower (UTM X: 0529091 Y: 4240129; Z: 785 m.s.n.m.) It could be considered a twin watchtower to the North one, though it is bigger and one rammed earth lift higher, that in this tower is equivalent to approximately 0.7575 m. It is also defined by a slightly rectangular ground plan of 7 x 5 varas (5.30 x 3.80 m) in an orthogonal position to the North watchtower. The access doors of these two watchtowers face each other. The change of orientation of the entry to this tower might be related to the purpose of two nearby watchtowers, situated on the top of two hills that do not seem to have any special strategic location with regard to the Segura valley. Both watchtowers are equidistant from a medieval road by a little more than 20 m. So, they could be linked to it for the purpose of controlling people, goods or the passage of cattle and perhaps for taxation purposes at some period in time. The height of this watchtower is 20 varas (15.15 m). Its principal access is approximately 9 varas (6.85 m) from the ground. Originally, this tower had two elevated doors, but one of them was blocked and turned into a loophole, and in modern days it is still blocked. It is situated on the East façade, where the marks of the corbels that support the scaffoldings can be seen clearly. As in the case of the North watchtower, this one also has sloped walls in the North, South and East façades but the West face is almost plumb. The drainage of water from the terrace was through a gargoyle that have would have been located on the North façade, as can be seen by certain signs and spots. It is a three-story building, the first being composed of 9 rammed earth lifts, plus one more layer forming a foundation built with compacted rounded stones with lime mortar and earth. The second story has a height of 4 lifts, with the door centered in the North façade and three loopholes in the other sides. The third one is 3 layers in height with centered loopholes in the second one. The terrace would have had another two layers with battlements on top of them. 4 RESTORATION PROCESS IN THE TOWER OF GÓNTAR AND A PROJECT TO RESTORE THE TORRE DEL AGUA AND THE NORTH AND SOUTH SANTA CATALINA WATCHTOWERS Each of the building pathologies has had a separate treatment. The general criterion has been to keep the intervention just to the essential, altering as little as possible the preexistences and the preserved surfaces. The deformations and faults in the materials and historical elements have been preserved and, in general, there has been an attempt to keep visible the patina of time on the building. All the existing timber remains in lintels and loop-holes have been conserved in place, applying to them an insecticide and fungicidal treatment in order to protect them from attack by xylophagous insects, as was also done in the newly inserted pieces. The restoration process has been done from the principle of reversibility, being minimally aggressive on the original elements and barely visible: 4.1 Bridging for the walls In some of the towers has been projected and patented a structural reinforcement solution to tie the walls in a non-rigid way, allowing them some movement. The process consists of the introduction of laminated timber bands connected to the walls with a series of stainless steel rods, which in its exterior part has a cable of the same material that works as a spring to absorb excessive expansion of the walls. These bands are separated by means of an expansion joint of extruded polystyrene 5 cm width (Fig. 7). 340 REHAB 2014 R. Amoêda, S. Lira & C. Pinheiro (eds.)