摘要: Description　　The city of Gaziantep is located on the edge of the Alleben Stream and the settlement history of the city dates to end of the 5th century. The stream flows by winding the settlement area

Description

　　The city of Gaziantep is located on the edge of the Alleben Stream and the settlement history of the city dates to end of the 5^th century. The stream flows by winding the settlement area in C shape. However, Alleben Stream is low in water and the water level is further reduced by increasing summer temperature. The Gaziantep Plateau also has a small number of streams. Moreover, the geological structure of the Gaziantep Region does not allow for lake formation. Depending on the geological structure, a large part of the rainfall seeps underground and forms underground waters. For all these reasons, the settlement has required water transport. In the province of Gaziantep, summers are warm and hot. If water is transported by surface water, it will evaporate in a considerable amount, especially in summer. At this point, the formation of soft limestone, clayey limestone and chalk formation that the city situated on made it possible to excavate the water tunnels underground, and thanks to the tunnel opening to the main rock, the water is moved to the settlement from the source.

　　The historical water system of Gaziantep consists of underground water tunnels (livas in local language) that bring water to the city from the main source far from the settlement area and the water structures (kastel in local language) that open the water coming from these tunnels for use.

　　Livas’ are underground water tunnels created with human labor by digging the limestone rock block that the city was built on. The essence of the livas system is based on the principle of bringing water from a source outside the settlement to the center of the city with underground water tunnels, delivering it to large settlements through well-calculated gently sloping underground tunnels and distributing it to water structures at the required places. As the city grew, the underground water network was enlarged by opening the new tunnels in the same way. This has created the ‘system of livas’ that surrounds the underground of the city as a cobweb and continues for miles.

　　The oldest livas line carrying water to the old city center is the Pancarlı Livas Line which carries water to the city from about 14 km northwest of the city. The period of construction and the origin of the system have yet to be ascertained, however it is clear that the system has been added to over time in parallel with the growth of the settlement. It is understood from the registry records of the Ottoman era that this line proved to be an important water line providing water for many monumental structures in the city, such as khans, madrasahs, baths, mosques, fountains and private houses by way of wells. The livas' also provided water to special structures for the public usage of water, referred to locally as kastels. 

　　Kastels are structures where water from the livas’ is opened for public use. Depending on the elevation of livas, kastels are located at varying depths based on the level of the livas lines. Instead of taking the water up with an additional system, the constructions were built at the water level. Some of the kastels reaching to the present day are "completely below- ground kastels" while some of them are "partly below-ground kastels". Kastels are quite comprehensively planned structures for that they include spatial arrangements for many different functions, serving as pools, wells, sitting places, small mosques, water closets and places for bathing. With these functions, kastels, together with the water-related service areas, has become an important meeting place in the daily social life of the city where people come together, spend time, do their work and perform their religious worship. They were also used to cool off during hot summer days. With the possibilities provided by these structures, they have brought along an important municipal social service.

　　There is a livas system that provides clean water for every kastel structure while the sewage is moved from the structures by another system. Along with having many livas network underground, some kastels get water from the same livas line. In addition, the following spaces are common in many kastels structures; pool, shower, toilet, mosque. Although we know to be more in quantity, six have reached to the present day:

1. Kastel of Pişirici (Beşinci)
2. Kastel of İhsan Bey (Esenbek)
3. Kastel of Şeyh Fethullah
4. Kastel of Kozluca
5. Kastel of Ahmet Çelebi
6. Kastel of İmam Gazali

　　The Kastel of Pişirici (Beşinci): It is thought to have been constructed during the period of Mameluke, in the years of 1282-83. It is estimated that it is the oldest of the existing kastels in Gaziantep and it has the most developed plane scheme, with two connected spaces. Going down the stairs from ground level, the first space encountered houses pools, places to sit, WC and bathing pool, while the second space, which is divided from the first space with two steps, is functioned as a small mosque. Maintenance and repair work has been completed and it is open to public visit today.

　　The Kastel of İhsan Bey (Esenbek) Kastel: İhsan Bey (Esenbek) Kastel, which is located under the courtyard of the mosque, is one of those that are "completely below- ground kastels". It is dated to the 15^th century. While it is a rock-carved place, the spatial separation is made with masonry walls. The kastel in the present day includes a pool, places to sit and a small mosque, although earlier records indicate a number of changes and additions that have been made over time. Accordingly, it is apparent that WCs existed in the kastel. The cleaning work is completed and it serves as a museum today.

　　The Kastel of Şeyh Fethullah: It is located in the courtyard of Şeyh Fethullah Mosque., and was a part of the mosque complex, together with hamam, madrasa and zawiyah during the era. Currently, half of the kastel is above ground, although some parts have no upper structure. Documentation held by the Wakf of Şeyh Fethullah Efendi notes the existence of a U-shaped madrasah in the courtyard of the Mosque, and it is likely that the Kastel of Şeyh Fethullah was constructed below this madrasah, which no longer exists. The Kastel has two pools and WC spaces. It is still in use as a part of Şeyh Fethullah Mosque.

　　The Kastel of Kozluca: It is located at the south of the Kozluca Mosque. Half of the kastel is above ground with a traditional dwelling constructed over it.. The year of construction is unknown. The restoration of the kastel is completed and it serves as a museum today.The Kastel of Ahmet Çelebi: It is the one with the simplest plan scheme among kastels in Gaziantep reaching today. Currently, the kastel includes only a pool and a well, although earlier records show that it once contained WCs The Kastel is now used as a part of Ahmet Çelebi Mosque.

　　The Kastel of İmam Gazali: It is one of those that are "completely below- ground kastels". The year of construction is unknown. It has a simple plan scheme which resembles The Kastel of Ahmet Çelebi. There is a rock-carved place on the left side when the stairs are taken down. This place is used for worship. Continuing to step down from the stairs leads to a rock-carved place where only a pool is located. The authenticity has been protected. Restoration work is continuing.