Paleoflood hydrology: Origin, progress, prospects

From an origin in diverse studies of flood geomorphology and Quaternary geology, paleoflood hydrology emerged as a geophysical and an applied hydrological science during the 1970s and 1980s. Since acquiring its formal name in 1982, the most productive approach in paleoflood hydrology has become energy-based inverse hydraulic modeling of discrete paleoflood events, recorded in appropriate settings as slackwater deposits and other paleostage indicators (SWD-PSI), or as various threshold indicators of non-exceedence. Technological advances, particularly in hydraulic modeling and geochronology, were instrumental in moving the discipline to its present status. The most recent advances include (1) new techniques for the accurate geochronology of flood sediments, notably TAMS radiocarbon analyses and OSL dating, and (2) the phenomenal increase in computer power that allows complex hydraulic calculations to become feasible for routine studies. From its initial demonstration in the southwestern United States, SWD-PSI paleoflood hydrology proved its widespread applicability to various landscape environments. Particularly important studies have been accomplished in Australia, China, India, Israel, South Africa, Spain, and Thailand. Paleoflood hydrology has also generated its share of controversy, in part because of the differing viewpoints and attitudes of the two scientific traditions from which it emerged: Quaternary geology/geomorphology versus applied hydrologic/hydraulic engineering. Nevertheless, the future growth of the discipline is assured, given the rapid pace of discoveries that it engenders. Indeed, so many international studies exist that it is appropriate to pursue global syntheses to address interesting and timely questions of extreme flood phenomena in relation to global climatic change.