Over the past 15 years, the Lake Hongfeng Reservoir Ecosystem Field Scientific Observation and Research Station in Guizhou Province has developed into an integrated field platform for monitoring, research, demonstration, and service focused on plateau deep-water reservoirs. Addressing key scientific and technological challenges related to water resource utilization, water security, and aquatic ecological restoration in southwestern China, and building upon long-term, multi-parameter, fixed-site observations of typical reservoirs, this study synthesizes the station's main research achievements: (1) It clarified that reservoir ecosystems possess distinct eco-environmental features—such as great depth, multiple interfaces, inverse seasonal water-level fluctuations, and degradation of the drawdown zone—that significantly differentiate them from natural lakes. (2) It revealed the spatiotemporal dynamics of water quality and eutrophication in Guiyang's Lake Hongfeng and Lake Baihua from 2009 to 2025. (3) From 2003 to 2020, it quantified the relative contributions and mechanisms of climate change and nitrogen/phosphorus nutrients in driving algal blooms in lakes/reservoirs, underscoring the urgency of eutrophication control under a changing climate. (4) It discovered and demonstrated a dissolved inorganic carbon fertilization effect in karst reservoirs, which promotes phytoplankton succession from diatoms and chlorophytes to cyanobacteria, thereby elevating the risk of cyanobacterial blooms. (5) A multi-isotope tracing system was established, including dual-carbon isotopes (δ¹³C-Δ¹⁴C), nitrate nitrogen and oxygen isotopes (δ¹⁵N-δ¹⁸O), and phosphate oxygen isotopes (δ¹⁸O_p), providing crucial technical support for precise pollution source identification in watersheds. (6) Using independently developed in situ high-resolution observation technology for the sediment-water interface, the study quantified the phosphorus release flux at this interface in typical reservoirs and identified seasonally hypoxiadriven reductive dissolution of iron-bound phosphorus as a key mechanism of internal phosphorus loading. (7) A suite of ecological restoration technologies and materials—such as in situ sediment passivation, aerated bubble-plume oxygenation, and oxygen nanobubble-enhanced interface re-aeration—were developed and applied in typical reservoirs. Based on these findings, future research priorities for the Lake Hongfeng Station are proposed. Collectively, these outcomes provide important scientific and technological support for safeguarding water resources and water environment security in southwestern China.