Background Coal mining-induced subsidence areas with high water tables in the lower reaches of the Yellow River are encountered with pronounced contradictions between large-area water accumulation and issues including urban water scarcity, groundwater contamination, ecological degradation, and low farmland reclamation rates. These contradictions severely restrict the green, low-carbon transformation of cities with coal mines and hinder the high-quality development of the Yellow River basin. This study aims to explore the construction of plain reservoirs in these subsidence areas as a critical approach to the intensive utilization of water and land resources in the subsidence areas, as well as the ecological protection and high-quality development of the Yellow River basin. This will help more effectively integrate land and water resources, address water accumulation in the subsidence areas, and alleviate water scarcity in cities subjected to coal mining.

Methods  Initially, this study systematically summarized both theoretical frameworks and practical applications of plain reservoir construction in coal mining-induced subsidence areas with high water tables in China. Then, a comparative analysis of the advantages and limitations of techniques for proactive and passive reservoir construction was conducted, and the theoretical foundations and current status of proactive plain reservoir construction in the subsidence areas were introduced from four aspects. Based on the organization of existing practices across various subsidence areas, this study proposed prospects for proactive reservoir construction and evaluated its benefits and advantages.

Advances Active plain reservoir construction facilitates water storage, diversion, and supply and contributes to increased reservoir capacity and farmland reclamation rates. Therefore, it serves as an important method to effectively address the large-area water accumulation in coal mining-induced subsidence areas and mitigate urban water scarcity in mining areas with high water tables. Existing plain reservoirs in the subsidence areas are mostly constructed passively after water accumulation based on the environment. Accordingly, proactive plain reservoir construction in these areas suffers from a lack of practices, research into basic theory, and scientific and systematic theoretical and technical systems. In-depth investigations are required to address key scientific issues including (1) the damage and evolution of strata under the dynamic coupling between water accumulation and mining in the subsidence areas; (2) the optimization of mining plans, subsidence prediction, and reservoir capacity regulation; and (3) the intelligent, omnidirectional monitoring that integrates subsidence, water accumulation, and dams and covers full-time sequence. Active plain reservoir construction achieved by surface soil removal prior to surface subsidence can increase reservoir capacity by 30%-45% and farmland reclamation rates by 60%-70%, thus effectively ensuring sufficient water supply for regional agricultural and industrial development and ecological stability.

Prospects In the future, research on the basic theory should be intensified to ensure the safe construction and operation of the plain reservoirs. Regarding technological advancements, it is advisable to enhance the research, development, and application of novel technologies and materials to construct intelligent ecological reservoirs that integrate water storage, land reclamation, and carbon sink. In terms of policy and standards, it is necessary to establish improved, full-chain technical standards, incorporate the construction of plain reservoirs in the subsidence areas into the ecological restoration plans of mining areas, and ensure policy continuity and financial support. These advancements will provide directions and philosophy for the scientific construction and utilization of plain reservoirs in coal mining-induced subsidence areas with high water tables in the lower reaches of the Yellow River.