Visual Impact Assessment for Regulating Building Developments in the Scenery of a Large Historical Monument: the Case Study of Pra Pathom Chedi

Abstract

Inappropriate developments in the cultural heritage environment affect the perceived value of cultural heritage sites, especially large monuments. Despite the government’s attempt to establish visual management zones regulating the building height and setback, there is a lack of empirical evidence supporting appropriate restriction levels. Little is known about the public perception of visual impact on cultural heritages at different levels, particularly when disturbances (e.g. buildings) appear in the foreground and the middle ground of the scenes.
This study aims to assess the effectiveness of controlling building height and vista width to reduce the perceived impact of new developments on Phra Pathom Chedi in Nakhon Prathom Province. The public assessment was conducted to evaluate the appreciation and acceptance levels towards current and simulated scenery with varying restriction levels on building height and setback. Five control viewpoints of Pra Pathom Chedi were selected, and the representative images were created for the evaluation. Each viewpoint included four simulated scenarios modified from the reference images of the current development levels.
The results indicate that controlling building height and setback enhances the perceived value of cultural heritage, especially the buildings in the foreground. For the viewpoints with the monument as background, controlling the building heights to be no more than two-thirds of the perceived height of the cultural heritage seems to be a minimal restriction which does not create a conflict between appreciation and acceptance. Notably, expanding street width in the vista landscape demonstrated an effect on visual quality improvement comparable to or greater than stricter height control measures without any setback restriction.
These findings contribute valuable insights to urban planning and policy-making for managing developments in visual management zones of cultural heritage sites. The study proposes an approach that aims to balance preserving cultural and historical values with supporting appropriate urban growth, potentially reducing conflicts between conservation and development.