TY - JOUR
T1 - Paleoflood hydrology on the lower Green River, upper Colorado River Basin, USA
T2 - An example of a naturalist approach to flood-risk analysis
AU - Liu, Tao
AU - Greenbaum, Noam
AU - Baker, Victor R.
AU - Ji, Lin
AU - Onken, Jill
AU - Weisheit, John
AU - Porat, Naomi
AU - Rittenour, Tammy
N1 - Publisher Copyright:
© 2019
PY - 2020/1
Y1 - 2020/1
N2 - Through a comprehensive paleoflood hydrological investigation we document natural evidence for at least 27 high-magnitude paleofloods at six sites on the Lower Green River, Utah. Hydraulic analysis, using the Sedimentation and River Hydraulic-2D model (SRH-2D), shows that the responsible peak paleoflood discharges ranged between 500 and 7500 m3/s. At least 14 of these paleoflood discharge peaks exceed a level twice that of the maximum systematic record of gauged flows: 1929 m3/s. Geochronological analyses, employing optically stimulated luminescence (OSL) and radiocarbon dating techniques, demonstrate that these 14 largest paleoflood peaks occurred during the past 700 years. Integration of the paleoflood data into flood frequency analyses (FFA) reveals considerably higher values for the upper tails of the flood distribution than does a FFA based solely on the systematic gauged record, indicating that extreme floods are larger and more frequent than implied by the relatively short gauged record. Through examination of three approaches to extreme flood estimation – conventional FFA, probable maximum flood estimation (PMF), and paleoflood hydrology (PFH) – we show the significance of the natural evidence for advancing scientific understanding of extreme floods that naturally occur in the Colorado River system. We argue that this kind of scientific understanding is absolutely essential for achieving a credible evaluation of extreme flood risk in a watershed of immense importance to economic prosperity of the southwestern U.S.
AB - Through a comprehensive paleoflood hydrological investigation we document natural evidence for at least 27 high-magnitude paleofloods at six sites on the Lower Green River, Utah. Hydraulic analysis, using the Sedimentation and River Hydraulic-2D model (SRH-2D), shows that the responsible peak paleoflood discharges ranged between 500 and 7500 m3/s. At least 14 of these paleoflood discharge peaks exceed a level twice that of the maximum systematic record of gauged flows: 1929 m3/s. Geochronological analyses, employing optically stimulated luminescence (OSL) and radiocarbon dating techniques, demonstrate that these 14 largest paleoflood peaks occurred during the past 700 years. Integration of the paleoflood data into flood frequency analyses (FFA) reveals considerably higher values for the upper tails of the flood distribution than does a FFA based solely on the systematic gauged record, indicating that extreme floods are larger and more frequent than implied by the relatively short gauged record. Through examination of three approaches to extreme flood estimation – conventional FFA, probable maximum flood estimation (PMF), and paleoflood hydrology (PFH) – we show the significance of the natural evidence for advancing scientific understanding of extreme floods that naturally occur in the Colorado River system. We argue that this kind of scientific understanding is absolutely essential for achieving a credible evaluation of extreme flood risk in a watershed of immense importance to economic prosperity of the southwestern U.S.
KW - Flood-risk analysis
KW - Green river
KW - Naturalist approach
KW - Paleoflood hydrology
KW - Upper Colorado River Basin
UR - http://www.scopus.com/inward/record.url?scp=85075510475&partnerID=8YFLogxK
U2 - 10.1016/j.jhydrol.2019.124337
DO - 10.1016/j.jhydrol.2019.124337
M3 - Article
AN - SCOPUS:85075510475
SN - 0022-1694
VL - 580
JO - Journal of Hydrology
JF - Journal of Hydrology
M1 - 124337
ER -