Geospatial Technologies for Flood and Drought Management: A Review of Earth Observation Data, Procedures, and their Operational Effectiveness

Floods and droughts represent two of the most widespread hydrological hazards, frequently leading to large-scale socioeconomic disruption and long-term environmental degradation. The increasing frequency and intensity of these hazards, driven by climate change and rapid urbanization, require advanced and timely response mechanisms. Geospatial technologies, particularly Earth Observation (EO), have become essential in this context, providing multi-scale, near-real-time information to support disaster management. This review synthesizes the current state of EO-based flood and drought management, with a specific focus on the operational integration of EO data and procedures across key response substages. It assesses the capabilities of core EO sensor families, including optical, thermal infrared, active and passive microwave, and Light Detection and Ranging (LiDAR), in monitoring critical hydrological and environmental variables. A central contribution of this study is the development of the Operational EO Integration Framework (OEI-F), which systematically aligns EO data types, integration approaches, spatial scales, and response substages within an operational context. The review further examines advances in multi-source data fusion, EO-derived indicators, and service-oriented platforms, while identifying persistent challenges related to data interoperability, institutional uptake, and compound hazard monitoring. The findings underscore the pivotal role of EO in strengthening climate adaptation, multi-hazard resilience, and evidence-based decision-making, and conclude with strategic recommendations to enhance its operational effectiveness across technological, organizational, and policy dimensions.