The assessment of aquatic environments within Korea’s Environmental Impact Assessment (EIA) system primarily relies on physico-chemical parameters. Specifically, evaluations of aquatic ecosystems are limited to certain aspects of aquatic organism diversity (species composition and community characteristics), with no comprehensive assessment of ecosystem health or condition. This study investigates the application of aquatic ecosystem health indices in 89 projects involving the “Use and development of rivers,” conducted as part of EIAs between 2000 and 2022. It proposes improvements to the EIA system through the adoption of biological evaluation methods based on key aquatic organisms. This study conducts a comparative analysis of international cases of aquatic ecosystem health assessments and EIA systems to identify the limitations of Korea’s EIA system and propose improvements. It also investigates the application of aquatic ecosystem health indices in 89 projects involving the “Use and development of rivers,” conducted as part of EIAs between 2000 and 2022. Based on these findings, it suggests adopting biological evaluation methods based on key aquatic organisms to enhance the EIA system.
Globally, 12 countries, including the United States and Germany, conduct river monitoring and biological evaluations. Among them, six countries, including the United States, employ biological indices in their assessments. The United States, in particular, uses the Index of Biological Integrity (IBI) to evaluate aquatic ecosystem health. Furthermore, biological health assessments are incorporated into EIAs under the National Environmental Policy Act (NEPA) through the implementation of Rapid Bioassessment Protocols (RBPs). In Korea, aquatic ecosystem health assessments within EIAs primarily utilize indices from the National Biological Monitoring Network, established under the Water Environment Conservation Act (provisions for aquatic ecosystem health surveys and evaluations). The use of biological assessment indices includes 75 applications of the benthic macroinvertebrate index, 35 of the diatom index, and 21 of the fish index. Since the introduction of riverine aquatic ecosystem health evaluations in 2007, the frequency of their use has steadily increased, highlighting the growing recognition of ecosystem-level assessments in evaluating impacts on aquatic environments. However, the assessment of aquatic ecosystem health has yet to be institutionalized as a formal component of domestic EIAs, resulting in limited continuous evaluation and practical implementation. This study underscores the critical importance of ecosystem-level evaluations in EIAs of aquatic environments, such as rivers and lakes. It recommends incorporating aquatic ecosystem health indices as standardized survey items within the existing EIA framework for water environment assessments.