The Five-Decade Landsat Legacy in Inland Water Quality: A Systematic Review of Technological and Methodological Evolution

Monitoring the quality of lentic inland waters is essential for assessing ecosystem health, supporting sustainable water-resource management, and informing environmental policy. Although not originally designed for aquatic applications, the Landsat programme has become a cornerstone of inland water-quality remote sensing owing to its five-decade observational legacy, moderate spatial resolution, global coverage, and open-access archive. This systematic review synthesises 229 studies published between 1983 and 2026 to examine how the technological legacy of Landsat has shaped the evolution of lentic inland water-quality remote sensing. Web of Science and Scopus were systematically searched up to 10 June 2026 for studies using Landsat imagery to assess water-quality parameters in lentic inland waters. Riverine and coastal studies, reviews, non-English publications, and studies without an eligible Landsat-based water-quality assessment were excluded. Extracted evidence was qualitatively synthesized according to sensor, water-quality parameter, methodological approach, study period, geographic region, water-body type, and application. The synthesis reveals a transition from predominantly empirical approaches using the Multispectral Scanner and Thematic Mapper to greater bio-optical sensitivity and methodological diversification with the Operational Land Imager (OLI) and OLI-2, together with increased scientific production following the 2008 Landsat Open Data Policy. The review also identifies key limitations related to sensors, the environment, the atmosphere, data, and methodological limitations that continue to restrict model transferability and operational implementation. Building on these findings, we introduce the Landsat-to-Global Freshwater Intelligence Framework to guide more transferable and interoperable freshwater monitoring. No formal review protocol was prepared or registered.