Channel enlargement by avulsion-induced sediment starvation in the Saskatchewan River

Abstract

Research Article| April 01, 2014 Channel enlargement by avulsion-induced sediment starvation in the Saskatchewan River Norman D. Smith; Norman D. Smith 1Department of Earth & Atmospheric Sciences, University of Nebraska, Lincoln, Nebraska 68588-0340, USA Search for other works by this author on: GSW Google Scholar Galina S. Morozova; Galina S. Morozova 2School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada Search for other works by this author on: GSW Google Scholar Martin R. Gibling Martin R. Gibling 3Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Norman D. Smith 1Department of Earth & Atmospheric Sciences, University of Nebraska, Lincoln, Nebraska 68588-0340, USA Galina S. Morozova 2School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada Martin R. Gibling 3Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada Publisher: Geological Society of America Received: 01 Nov 2013 Revision Received: 27 Jan 2014 Accepted: 29 Jan 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (4): 355–358. https://doi.org/10.1130/G35258.1 Article history Received: 01 Nov 2013 Revision Received: 27 Jan 2014 Accepted: 29 Jan 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Norman D. Smith, Galina S. Morozova, Martin R. Gibling; Channel enlargement by avulsion-induced sediment starvation in the Saskatchewan River. Geology 2014;; 42 (4): 355–358. doi: https://doi.org/10.1130/G35258.1 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 SocietyGeology Search Advanced Search Abstract Can localized deposition resulting from river avulsion produce downstream sediment-starvation effects similar to those in channels downstream from dams? We explore this question by examining a 130 km reach of the Saskatchewan River (Canada) downstream of an active, 500 km2 avulsion belt initiated in the 1870s. Progradation history and measurements of bedload and channel-bed grain size indicate that little coarse sediment has escaped the avulsion belt since its inception. Comparisons of 17 channel cross sections surveyed in 1911, 1954–1956, and 2011–2012 show that bankfull areas enlarged by deepening and widening in the upper two-thirds of the study reach since 1911. Between 1911 and 1954–1956, average channel area increased by 35% in the upper 45 km, and as much as 44% locally. From 1954–1956 to 2011–2012, additional enlargement occurred in the upper 35 km, averaging 52% since 1911. These increases occurred despite a 24% decrease in mean annual discharge since 1913. These changes are interpreted as effects of sediment sequestration in the upstream avulsion belt. Net erosion by sediment-deficient outflows from areas of avulsive deposition may be an underappreciated process in evolving floodplains. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.