Value-based optimization model for cultural route design: Ancient Water Supply Heritage of Istanbul (Türkiye)

Cultural tourism has become an increasingly growing human activity in today's world. Therefore, various cultural/natural heritage areas or buildings face large tourist crowds, causing physical, social, or cultural deterioration. Cultural routes, which provide a systematic approach and planned tourists move, can reduce the negative effects of overtourism. This study aims to develop an optimization model as a supportive tool for the cultural route design process. The proposed optimization model aims to maximize cultural experience while satisfying constraints on heritage values, building types, historical eras, and general routing rules. Moreover, this model, creating optimized cultural routes, is expected to contribute to regulating economic income and tourist density. As a case study, the ancient water supply systems of Istanbul, inherited from the Roman and the Ottoman empires and currently overlooked, are investigated. Heritage values, mentioned in the extensive literature, are reviewed and the values/attributes for this study are appointed according to the characteristics of the case heritage assets, and their environment. The values of the case structures are evaluated with value analysis after field study. An optimum cultural route for Istanbul's historical water supply heritage, according to the objective and the constraints of the model, is obtained by solving the model with the case data. The resulting route can make this overlooked heritage of Istanbul recognized and spread the tourist density in the city center. The model is flexible, allowing for easy modification of the objective function, constraints, and values when designing routes across various heritage sites. This model can be used not only in the design of new cultural routes but also in optimizing existing routes.