Review article: A comprehensive review of compound flooding literature with a focus on coastal and estuarine regions

Compound flooding, where the combination or successive occurrence of two or more flood drivers leads to a greater impact, can exacerbate the adverse consequences of flooding, particularly in coastal–estuarine regions. This paper reviews the practices and trends in coastal–estuarine compound flood research and synthesizes regional to global findings. A systematic review is employed to construct a literature database of 279 studies relevant to compound flooding in a coastal–estuarine context. This review explores the types of compound flood events and their mechanistic processes, and it synthesizes terminology throughout the literature. Considered in the review are six flood drivers (fluvial, pluvial, coastal, groundwater, damming/dam failure, and tsunami) and five precursor events and environmental conditions (soil moisture, snow, temp/heat, fire, and drought). Furthermore, this review summarizes research methodology and study application trends, as well as considers the influences of climate change and urban environments. Finally, this review highlights knowledge gaps in compound flood research and discusses the implications on future practices. Our five recommendations for compound flood research are (1) adopt consistent terminology and approaches, (2) expand the geographic coverage of research, (3) pursue more inter-comparison projects, (4) develop modelling frameworks that better couple dynamic Earth systems, and (5) design urban and coastal infrastructure with compounding in mind.