Paleodischarge of the late Pleistocene Bonneville Flood, Snake River, Idaho, computed from new evidence

Research Article| July 01, 1987 Paleodischarge of the late Pleistocene Bonneville Flood, Snake River, Idaho, computed from new evidence ROBERT D. JARRETT; ROBERT D. JARRETT 1U.S. Geological Survey, Federal Center, Box 25046, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar HAROLD E. MALDE HAROLD E. MALDE 1U.S. Geological Survey, Federal Center, Box 25046, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information ROBERT D. JARRETT 1U.S. Geological Survey, Federal Center, Box 25046, Denver, Colorado 80225 HAROLD E. MALDE 1U.S. Geological Survey, Federal Center, Box 25046, Denver, Colorado 80225 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1987) 99 (1): 127–134. https://doi.org/10.1130/0016-7606(1987)99<127:POTLPB>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation ROBERT D. JARRETT, HAROLD E. MALDE; Paleodischarge of the late Pleistocene Bonneville Flood, Snake River, Idaho, computed from new evidence. GSA Bulletin 1987;; 99 (1): 127–134. doi: https://doi.org/10.1130/0016-7606(1987)99<127:POTLPB>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Bonneville Flood resulted from catastrophic outflow from Pleistocene Lake Bonneville about 15,000 yr ago, when the lake overtopped its rim at Red Rock Pass in southeastern Idaho and discharged a vast volume of water down the Snake River. This paper provides revised estimates of the paleodischarge, volume, and duration of the Bonneville Flood, based on new evidence of its height and on current understanding of the amount of lowering of Lake Bonneville. Evidence for the revised height of the flood is derived from the altitude of erosional features and flood deposits at the head of a constricted reach of the Snake River Canyon at the mouth of Sinker Creek and from the altitudes of flood deposits at several places about 53 km upstream.Using the step-backwater method, we estimate that peak discharge for the Bonneville Flood through the constricted reach was from 793,000 to 1,020,000 m3/s and most likely was 935,000 m3/s. This discharge is 2.2 times the discharge previously reported and is the second largest flood known to have occurred in the world. At this rate of discharge, the shear stress for the flood would have been 2,500 N/m2, and the unit stream power would have been 75,000 N/m/s, as compared with values of 6 to 10 N/m2 and 12 N/m/s for recent floods on the Mississippi and the Amazon. Other recent studies of the history of Lake Bonneville show that the volume of water released was 4,700 km3, or about 3 times greater than the volume previously inferred. Although this volume indicates a flood duration of 8 weeks at constant peak discharge, an accurate estimate of the duration would require dam-break modeling at Red Rock Pass. From a dam-break model, flood hydrographs at Red Rock Pass and the hydraulics of the flood wave along the Snake River could be computed. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.