Significance and Enlightenment of Implementing Water Ecological Assessment

The quality of aquatic ecology is a fundamental indicator of the condition of water bodies and their environments. Maintaining the integrity of aquatic ecosystems is essential for the conservation of water resources and the rehabilitation of aquatic habitats. Characterizing and evaluating the health and quality of these ecosystems remains a substantial challenge in international research and exploration of this field. This paper surveys the evolution, index system, change process and difficulties of international practices in aquatic ecological assessment, highlighting the principal experiences and pivotal insights gained from assessments conducted in typical countries and organization around the world, including the United States, the European Union, the United Nation, China, Brazil and India. Research on and application of water ecological assessments have demonstrated significant advancements in technological and methodological approaches, marking a notable transition from general scientific evaluations to more targeted assessments. This evolution also reflects the continuous improvement and refinement of policies and management strategies. However, the identification and measurement of water quality indicators, particularly biological indicators, are crucial to aquatic ecosystems. The biological indicators used currently, such as fish, benthic organisms, plankton, macrophytes, and periphyton, have the problems of excessive assessment variables, testing difficulties, and limited precision in gauging the level of ecological health. Therefore, it is necessary to standardize a set of core indicators and establish a methodological framework that is accurate, easily measurable, and conducive to routine operations. This presents a challenging scientific and technological research topic. • Water ecological assessment faces human-induced and naturally occurring challenges. • The evolution, indicators, changes, difficulties, enlightenment and outlook were studied. • Indicators refer to hydrology, water quality, habitats, organisms, and ecological services. • The unification, integration, standardization, and sustainability are suggested being enhanced.