The construction of dams, as one of the fundamental strategies for water resources management, has always been accompanied by environmental challenges. This study conducts a comprehensive environmental impact assessment (EIA) of the Haleh Dam located in Kuhdasht County, Lorestan Province, Iran. The methodological approach integrates a quantified checklist with the modified Iranian Leopold matrix to enable a precise and comparative analysis of impacts during both construction and operation phases. Evaluations were performed based on three criteria—significance, intensity, and nature of effects—across four environmental dimensions: physical, biological, socio‑economic, and cultural.
The findings indicate that during the construction phase, the implementation scenario (−146) demonstrated a relatively lower adverse impact compared to the non‑implementation scenario (−160), while the operation phase (+378) revealed long‑term positive effects mainly in the socio‑economic dimension (+155), such as improved water supply, flood regulation, and job generation. Nevertheless, several components, particularly terrestrial habitats and surface water quality, experienced moderate to high negative impacts during construction.
Therefore, the study suggests that the Haleh Dam may be considered environmentally justifiable, conditional upon the effective implementation of mitigation and monitoring measures. It also acknowledges inherent methodological limitations, including reliance on expert judgment for scoring and the lack of post‑implementation monitoring data. Despite these constraints, the proposed integrated approach provides a practical framework for EIA in data‑limited contexts and can support sustainable assessment of similar water infrastructure projects in developing regions.