A STRATEGY USING HERITAGE DOCUMENTATION FOR MANAGING CHANGE OF THE HISTORIC CENTRE OF BUKHARA

: Bukhara, historic city of the Silk Roads, has been going through changes for more than 2000 years. The historic centre is UNESCO World Heritage since 1993 including hundreds of monuments such as madrassas, mosques and caravanserais, and an urban fabric containing the traditional Bukharian houses. As a dynamic city in Uzbekistan, its transformation is ongoing. A number of previous studies, including a large scale UNESCO field campaign, have been carried out to identify the overall condition of this historic city. Being most of the traditional houses privately owned and built of earthen materials, these studies have highlighted that this type of heritage is under threat of high impact of changes. Therefore, there has been a need of guidelines to protect and manage change of this outstanding heritage. Appropriate decisions in heritage conservation are based on timely, relevant and accurate information about the conditions, materials and evolution of heritage buildings and landscapes. To support these tasks, two main international projects, the University College London (UCL) Central Asian Archaeological Landscapes (CAAL) funded by Arcadia Fund, and the Traditional Bukharian Houses Documentation and Conservation approaches funded by the World Monuments Fund (WMF) are supporting the heritage management of city of Bukhara in partnership with the International Institute of Central Asian Studies (IICAS), the local administration, universities and the Bukharian community. This paper presents the current two large projects to create a digital database of the mahallas - neighbourhoods and its traditional houses by documenting heritage attributes, and ultimately produce the Guidelines on Conservation, Maintenance and Adaptive Reuse recognising heritage regeneration, as a core principle, and the contribution of heritage towards the achievement of the UN 2030 Agenda and its Sustainable Development Goals (SDGs).


Digital Bukhara Past, Present and Future
Bukhara situated on the Silk Roads in current Uzbekistan is over 2000 years old (see Figure 1). Over centuries, caravans transported silk, spices and other precious goods from the Far East to Europe along the Silk Roads. Bukhara was an important stop-over for caravans, it was a place where not only goods, but also culture and ideas were exchanged. Bukhara developed into an important city for Islamic culture. Today, Bukhara is still a unique example of medieval city along the Central Asian Silk Roads. As such, the Historic Centre of Bukhara became a UNESCO World Heritage property in 1993 as this heritage area meets three criteria of Outstanding Universal Value (OUV) (Republic of Uzbekistan, 2012). The criteria not only recognise monumental building such as mausoleums, caravanserais and madrassahs, but also the urban fabric with its traditional water system, mahallas -neighbourhoods and vernacular architecture as illustrated in Figure 2. After the designation of Bukhara as World Heritage, its protection became a commitment of the Republic of Uzbekistan and Bukharians. These obligations are fixed legally at three levels: international, national and local (see Table 1) (UNESCO, 1972a;Republic of Uzbekistan, 2001).
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume X-M-1-2023 29th CIPA Symposium "Documenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Future", 25-30 June 2023, Florence, Italy Table 1. Legal framework of Bukhara as World Heritage.
Extensive work has been carried out in the historic centre of Bukhara towards its protection as an outstanding cultural heritage, while managing change. From 2008 to 2013 the UNESCO Office in Tashkent in collaboration with international and national universities carried out a survey of the Historic Centre of Bukhara World Heritage property. It was a rapid survey to identify the state of conservation of the dwellings, social factors and needs of the people living within the listed property (Vileikis andAllayarov, 2014, 2015;Vileikis et al., 2017). As a result, the survey 216 hectares of World Heritage area and more than 4000 dwellings. In addition, other inventories have been taking place with specific focus as the studies of the Center for Jewish Art (CJA).
Both, the comprehensive survey of UNESCO and the 1990s CJA database were a good initial baseline information as a record of the historic city. However, to manage the living historic centre of Bukhara and propose guidelines for conservation, maintenance and adaptive reuse that will answer to the current needs, more detailed and updated survey was needed.
In 2019, the Central Asian Archaeological Landscapes (CAAL) a University College London (UCL) and Arcadia Fund funded project was launched with the aim to map and create a database of the Central Asian cultural heritage, including the Historic Centre of Bukhara. One year after, the World Monuments Fund in partnership with the International Institute of Central Asian Studies (IICAS) initiated the project for the documentation and development of conservation guidelines for the city. The earlier has been building a Geospatial Information System (GIS) database of the historic urban landscape e.g. monuments, sites and dwellings. The latter aimed to record in detail the traditional Bukharian houses and mahallas. This paper will present the two current large heritage documentation studies towards the development of the conservation guidelines and supporting decision making of the cultural tangible and intangible heritage in the dynamic city of Bukhara. The results presented are part of the research of the author, in collaboration with the local team in Bukhara.

Documentation for Cultural Heritage
The United Nations (2015) recognizes with its Sustainable Development Goals (SDG) that the world should "Strengthen efforts to protect and safeguard the world's cultural and natural heritage" (Goal 11.4) to "make cities and human settlements inclusive, safe, resilient and sustainable" (Goal 11). For this reason, identification and documentation of cultural heritage is a key component in the development of mankind. As stated by Clark (2010), understanding a heritage site is the first step to selecting any conservation strategy, and documentation is the first step in understanding. Documentation and well-established baseline information can serve in the study and protection of a heritage site by recording its values and monitoring its integrity over time. Thus, appropriate decisions in heritage conservation are based on timely, relevant and accurate information about the conditions, materials and evolution of heritage buildings and landscapes.
Aside from the Convention concerning the Protection of World Cultural and Natural Heritage (UNESCO, 1972a), there are other conventions and internationally recognized charters for cultural heritage and documentation standards (UNESCO, 1972b;ICOMOS, 1996;Historic England, 2016). They aim to guide stakeholders and site managers to improve its documentation and interpretation of the sites. These documents provide guidance of the use of digital tools, workflows and platforms for a wide range of levels of documentation detail and scales of the sites.
Digital tools are used in the heritage recording process to acquire, process, and produce digital media, including all digital data capture forms, ranging from photographs to rectified images, CAD to photogrammetry, use of drones, total station to 3D scanning, as well as others such as lidar sensors and emerging devices. They can be divided into metric surveying and recording, and other non-destructive diagnostic techniques. Digital workflows are the methods or approaches utilized by heritage recording specialists to carry out a cultural heritage digital recording. A summary list of workflows and tools for heritage recording is shown in determine cause and cleaning methods e.g. for stone staining; in monitoring to take controlled photopoints Luhmann, 2004;Remondino, 2011;Shum and Szeliski, 2000;Walton, 2003;Fangi, 2010 (Carlisle et al., 2014). Current examples of the implementation of Arches as a platform to inventory and map its historic resources are the HistoricPlacesLA of the City of Los Angeles, the Philippine Heritage Map, and the National Heritage Inventory of the Kingdom of Bhutan (Myers, 2016;Williams, 2016). Recently, Historic England developed Arches for the heritage inventory of Greater London and the City of Lincoln. In addition, the Global Digital Heritage project has an implementation of Arches including 3D data.

METHODS
The heritage documentation methods below were used to map and survey tangible and intangible cultural heritage of the selected areas of the Historic Centre of Bukhara, serving as a pilot project for further detail survey. The assessment was conducted at two levels of scale: mahalla (urban scale) and traditional houses (architectural scale).

Values Assessment -definition of attributes
Identification of attributes was carried out for the two levels of scale, and based on the OUV and criteria of the World Heritage property -the why. The definition of these attributes is relevant to the documentation strategy as they reveal -the what is documented. Large literature review, archival research and focal meetings with the local teams supported this task.

Mahalla:
The Mahalla is a unique phenomenon of Central Asia. The Mahallas were originally founded by a family, ethnic or professional community. Each mahalla had its own boundaries where families had their own lands with courtyard houses. In the 20th century, the mahallas also gained an administrative function as the smallest units of local authorities. The following are the attributes of a mahalla: • Narrow streets • Labyrinth Street layout (Urban Pattern) • Two High and Proportion • Water System • Exterior Materials: timber, frame and brick for the houses (earth) and no payment for the streets Figure 5. Traditional house illustrating the attributes that convey the OUV from the exterior façades. Figure 6. Traditional house illustrating the attributes that convey the OUV in the interior courtyard.

Traditional Houses:
The vernacular architecture of Bukhara is highly unique for Central Asia. The following were the attributes identified characteristic of this typology. They present a high contrast between the exterior and the interior: • Delicate traditional materials and techniques: timber frame and brick (clay, row or burnt) infillings finished by clay plaster • Modest facades and flat roofs • Modest entrance and doors • Sophisticated form and functional structure with restricted height • Lively courtyards • Summer aivan or nim-aivan -including windows and timber columns • Decorated mekhmonkhona -guestroom.

Mahalla Mapping
A QGIS database was developed based on the UNESCO database survey (2008)(2009)(2010)(2011)(2012)(2013). It contains the records and state of conservation of 4417 dwellings. The database was adapted to the standards of the CAAL project for a consistent integration (see figure 7). QGIS was selected as a tool as it is Free and Open Source Software (FOSS). As the UNESCO database was already built using international standards for cultural heritage, no major changes were implemented, for example, additional values were created related specifically to the traditional houses such as materials and courtyard typologies. A public platform using Arches Data Management System is under development. As shown in Figure 8, a smaller area of study within the historic centre was selected for detail survey. The area of study was surveyed based on the map of Bukhara of 1910 by Parpheov and Fenin (Gangler et al, 2004), superimposed on the orthophoto ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume X-M-1-2023 29th CIPA Symposium "Documenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Future", 25-30 June 2023, Florence, Italy taken in 2021 by the International Institute of Central Asian Studies (IICAS). The orthophoto was produced from aerial photogrammetry taken by DJI Mavi 2 Pro with a height of 80 meters. georeferenced orthophoto from aerial photogrammetry.
The orthophoto supported the analysis of the mahallas urban fabric and structure. A high percentage of the houses have changed their flat roofs for inclined roofs. The earlier are easier to maintain as the original ones made of earth require high maintenance and special traditional techniques (see Figure 9).
All streets were systematically recorded using the Insta360. As shown in figure 5, the use of the 360 photos and videos of the urban fabric were a rapid ground recording technique that allowed after the field survey a detail assessment such as type of pavement, electricity poles or urban furniture. It also recorded the intangible heritage of Bukhara and the daily lives of Bukharians, such as the markets and children going to school in the mornings serving as a snapshot in time of the city. 137 360 degrees videos were produced. New studies by Barazzetti et al. (2020) for condition mapping using 360 degrees images are under development. Thus, this data collected could have a further in the future. Figure 10. Example of photos extratected from 360 videos using Insta360.

Survey of Traditional Houses
A detailed survey was conducted to a selected number of houses. The prioritized houses were on the national heritage list or identified by the previous surveys as having high heritage values. Figure 11. Filled out example of survey form for values and condition assessments.
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume X-M-1-2023 29th CIPA Symposium "Documenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Future", 25-30 June 2023, Florence, Italy A fiche was created for each one of these houses after carrying out door-to-door interviews and documentation (see Figure 11). The fiche follows the same international recognised standards of the UNESCO survey (2008-2013) (for further details see Vileikis et al (2017).
A comparison between this updated survey and the previous allowed to understand the changes of the houses and the needs of the homeowners. The traditional houses are changing as they need to be adapted to the current needs of the owners. These changes were always part of the living heritage where families were growing or getting smaller, the houses were single-family homes or community shared houses, or the owners changed with different religions. Despite this changes, a number of attributes remained, the most prominent the courtyard and the ayvans. The mekhmonkhona keeps of being the main room, but it is sometimes used also as a bedroom, or has adopted other uses based on the needs of the homeowner.
Three houses were surveyed with the CAM 2 Focus FARO 3D scanner and photogrammetry to capture high quality of details (see Figure 12). From them, architectural drawings were drawn using AutoCAD. These records are example of best-preserved traditional houses of Bukhara.

Cultural Mapping
Beyond the global significance, the Historic Centre of Bukhara provides its residents with a range of economic, social and recreational values -it is a living heritage reflecting the outstanding traditional Bukharian lifestyle. The Historic Centre of Bukhara also contributes to sustainable development, the UN Agenda 2030 and its 17 Sustainable Development Goals (SDG). The traditional houses contain intangible histories that has passed through generations and were linked to the houses.
To record these histories, interviews to three homeowners were carried out. These were recorded to make a short documentary film: Three Houses, Three Stories, One Bukhara. The homeowners highlighted the importance of Bukhara as a multicultural city, and they hope this will remain in the coming generations (see Figure 13).

Guidelines for Conservation, Maintenance and Adaptive Reuse
The Historic Centre of Bukhara has adopted a Conservation Approach for any interventions within the historic centre. They have been drafted to align them with international standards, but adapted under a values-based approach for the wider local context taking the UNESCO (2011) Recommendation on Historic Urban Landscape (HUL) into account. The main conservation activity is to safeguard all the attributes identified, taking as a priority the ones directly expressing or contributing to the OUV. This will mean to continuously maintain these attributes and take actions to reduce the risks that might have a negative impact on them.

CONCLUSION
The Historic Centre of Bukhara, World Heritage property since 1993, is an outstanding example of heritage and wider values of a living central Asian city. As all cities, changes are a major threat to the heritage values, however with systematic and high standards documentation and information, the city responsible authorities could better make decisions and manage change.
With the support of two international projects and a large database of previous studies two international projects were launch to support two levels of recording: mahalla and traditional houses. The results successfully used a combination of digital heritage recording techniques, including aerial and terrestrial photogrammetry, 3D scanning, 360 degrees videos and photos, context and detail photos, and video recording to capture the current state of the historic city.
Based on the updated information and previous studies, Guidelines for Conservation, Maintenance and Adaptive Reuse were produced. This documennt will serve as a guide for residents and owners of the traditional houses. In addition, the GIS database of the city was updated. Further dissemination and workshops on the implementation of the guidelines, as well as training on the use of GIS for the relevant authorities, is foreseen.
Changes in historic cities are foreseeable. Homeowners are looking towards good quality of life, and commodities of the 21 st century, and this requires a different approach in conservation of traditional houses. The heritage documentation of the historic city of Bukhara has been an ongoing systematic process that the city should embedded as part of their regular policies and workflows, a challenge still open to surpass.