Research Article| April 01, 1998 Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil Thomas Dunne; Thomas Dunne 1Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, California 93106-5131 Search for other works by this author on: GSW Google Scholar Leal A. K. Mertes; Leal A. K. Mertes 2Department of Geography and Institute for Computational Earth System Science, University of California, Santa Barbara, California 93106-4060 Search for other works by this author on: GSW Google Scholar Robert H. Meade; Robert H. Meade 3Water Resources Division, U.S. Geological Survey, Federal Center, Denver, Colorado 80225-0046 Search for other works by this author on: GSW Google Scholar Jeffrey E. Richey; Jeffrey E. Richey 4School of Oceanography, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar Bruce R. Forsberg Bruce R. Forsberg 5Instituto Nacional de Pesquisas da Amazoônia, Manaus, AM Brazil Search for other works by this author on: GSW Google Scholar Author and Article Information Thomas Dunne 1Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, California 93106-5131 Leal A. K. Mertes 2Department of Geography and Institute for Computational Earth System Science, University of California, Santa Barbara, California 93106-4060 Robert H. Meade 3Water Resources Division, U.S. Geological Survey, Federal Center, Denver, Colorado 80225-0046 Jeffrey E. Richey 4School of Oceanography, University of Washington, Seattle, Washington 98195 Bruce R. Forsberg 5Instituto Nacional de Pesquisas da Amazoônia, Manaus, AM Brazil Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1998) 110 (4): 450–467. https://doi.org/10.1130/0016-7606(1998)110<0450:EOSBTF>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Thomas Dunne, Leal A. K. Mertes, Robert H. Meade, Jeffrey E. Richey, Bruce R. Forsberg; Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil. GSA Bulletin 1998;; 110 (4): 450–467. doi: https://doi.org/10.1130/0016-7606(1998)110<0450:EOSBTF>2.3.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 Sediment transport through the Brazilian sector of the Amazon River valley, a distance of 2010 km, involves exchanges between the channel and the flood plain that in each direction exceed the annual flux of sediment out of the river at Óbidos (∼1200 Mt yr−1). The exchanges occur through bank erosion, bar deposition, settling from diffuse overbank flow, and sedimentation in flood-plain channels. We estimated the magnitude of these exchanges for each of 10 reaches of the valley, and combined them with calculations of sediment transport into and out of the reaches based on sediment sampling and flow records to define a sediment budget for each reach. Residuals in the sediment budget of a reach include errors of estimation and erosion or deposition within the channel. The annual supply of sediment entering the channel from bank erosion was estimated to average 1570 Mt yr−1 (1.3 × the Óbidos flux) and the amount transferred from channel transport to the bars (380 Mt yr−1) and the flood plain (460 Mt yr−1 in channelized flow; 1230 Mt yr−1 in diffuse overbank flow) totaled 2070 Mt yr−1 (1.7 × the Óbidos flux). Thus, deposition on the bars and flood plain exceeded bank erosion by 500 Mt yr−1 over a 10–16 yr period. Sampling and calculation of sediment loads in the channel indicate a net accumulation in the valley floor of approximately 200 Mt yr−1 over 16 yr, crudely validating the process-based calculations of the sediment budget, which in turn illuminate the physical controls on each exchange process. Another 300–400 Mt yr−1 are deposited in a delta plain downstream of Óbidos. The components of the sediment budget reflect hydrologic characteristics of the valley floor and geomorphic characteristics of the channel and flood plain, which in turn are influenced by tectonic features of the Amazon structural trough. 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.