Heritage Impact Assessment (HIA) has recently emerged as a conflict-solving tool to improve World Heritage (WH) conservation in line with sustainable development policies. The increasing number of requested HIAs for affected WH properties over the last years reveals that more attention is being paid to HIA as a practical tool to adequately support the protection and management of historic monuments and sites against new constructions and development. However, the application of integrated and systematic impact assessment methods within HIA still remains a key challenge in different HIA projects. Therefore, this paper contributes to the further development of a transparent and systematic procedure of HIA in accordance with Environmental Impact Assessment (EIA). It also explores different standard methods of impact assessment in EIA and discusses their applicability to cultural World Heritage properties. Finally, the paper emphasizes a need for developing integrated impact assessment methods to address the multiple impacts of development projects. Such methodological enhancement can further contribute to mitigation strategies and decision-making to protect World Heritage properties within the context of sustainable development.

Despite various opportunities, urban development projects have been causing significant challenges to the preservation and conservation of historic cultural heritage. In particular, an increasing number of World Heritage (WH) properties are impacted by the direct and indirect effects of development projects, reflecting the existing uprising conflict. Grasping the challenge, Heritage Impact Assessment (HIA) has been developed as a proactive assessment tool to identify and predict potential impacts, mitigate the negative impacts on heritage values, and sustain the attributes conveying OUVs in WH assets. The growing demand for urban development and its potential impacts on cultural heritage properties underscores the necessity for the development of a targeted Heritage Impact Assessment methodology for urban development threats. To adequately address multiple impacts, this paper proposes a triangulation of a qualitative matrix for impact identification and a semi-quantitative indicator-based index for impact analysis and evaluation. The methodology is applied to the World Heritage property of Masjed-e Jame of Isfahan in Iran. In drawing upon this example, a systematic and integrated impact assessment procedure is developed to capture a broad category of potential impacts and their significance that is crucial for determining site-specific mitigation strategies and informed decision-making within the context of heritage management and sustainable urban development.