A Down-to-Earth Examination of Hydrological Natural Disasters and Risk Using Earth Observations

Hydrological natural disasters, such as floods, droughts, and hurricanes, historically result in significant social, economic, and environmental loss. With predictions that climate change will likely increase the intensity and frequency of hydrological hazards, there is a need to improve understanding of hydrological extremes and their associated risk to society. The objectives of this dissertation are to advance the applications of space-based Earth Observations for monitoring components of the terrestrial water cycle and to assess risk of hydrological disasters with attention to societal priorities. The following five interdisciplinary studies are investigated in this dissertation. First, a foundational comparison of optical versus radar Earth Observations is demonstrated for delineation of inland waterbodies, a vital storage component of the hydrological cycle. Second, recent hydrometeorological extremes are spatially and temporally examined in the Lake Victoria Basin, a data-sparse region particularly vulnerable to climate extremes. Third, risk of hurricane scenarios is quantified and mapped as the disruption of system order using social vulnerability indices and hydrology data from disparate sources. Fourth, resilience of vulnerable populations to multidecadal climate change is modeled for examination of environmental justice priorities in a region of the southeastern USA. Fifth, basins that face current and/or future water scarcity risk are identified and mapped in Iraq and transboundary regions. Methodologies and findings of this dissertation serve as an important step in supporting global efforts aimed to increase decision maker accessibility to timely and accurate Earth Observations in support of hydrological disaster risk reduction, particularly for the most vulnerable communities.