Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona

Research Article| June 01, 1984 Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona RICHARD HEREFORD RICHARD HEREFORD 1U.S. Geological Survey, 2255 North Gemini Drive, Flagstaff, Arizona 86001 Search for other works by this author on: GSW Google Scholar Author and Article Information RICHARD HEREFORD 1U.S. Geological Survey, 2255 North Gemini Drive, Flagstaff, Arizona 86001 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1984) 95 (6): 654–668. https://doi.org/10.1130/0016-7606(1984)95<654:CAEPTG>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 MailTo Tools Icon Tools Get Permissions Search Site Citation RICHARD HEREFORD; Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona. GSA Bulletin 1984;; 95 (6): 654–668. doi: https://doi.org/10.1130/0016-7606(1984)95<654:CAEPTG>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 During the first 40 years of the twentieth century, erosion was the dominant geomorphic process affecting the morphology of the Little Colorado River channel. The discharge regimen was one of frequent large floods and high annual discharge that created a wide sandy channel free of vegetation. In the 1940s and early 1950s, average annual precipitation declined, reducing annual discharge to about 57% of that of the preceding period as well as reducing the frequency of large floods. The channel adjusted to the new hydrologic regimen by reducing its width. Parts of the channel were frequently dry, and riparian vegetation, primarily nonnative salt cedar, became established on the higher channel surfaces. Precipitation and discharge thereafter increased and aggradation by overbank deposition was the primary geomorphic process, as indicated by accretion of 2 to 5 m of flood-plain alluvium between 1952 and 1978. Events of 1980, however, suggest that the flood plain has ceased to accrete, although climate has not fluctuated. The flood plain has probably reached a critical height above the channel, beyond which further accretion is unlikely under the existing discharge regimen. The recent history of the Little Colorado broadly suggests that flood-plain development was initiated by climatically induced hydrologic fluctuations. Flood-plain deposits in the stratigraphic column of such ephemeral streams may record repeated adjustments to altered hydrologic conditions. 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.