Portal de Periódicos da CAPES

Role of Bedrock Ground Water in the Initiation of Debris Flows and Sustained Post-Flow Stream Discharge

1990; Geological Society of America; Volume: xxvii; Issue: 1 Linguagem: Inglês

10.2113/gseegeosci.xxvii.1.73

1558-9161

Christopher C. Mathewson, Jeffrey R. Keaton, Paul M. Santi,

Soil and Unsaturated Flow

Research Article| February 01, 1990 Role of Bedrock Ground Water in the Initiation of Debris Flows and Sustained Post-Flow Stream Discharge CHRISTOPHER C. MATHEWSON; CHRISTOPHER C. MATHEWSON Center for Engineering Geosciences, Department of Geology, Texas A&M University, College Station, TX 77843-3115 Search for other works by this author on: GSW Google Scholar JEFFREY R. KEATON; JEFFREY R. KEATON Center for Engineering Geosciences, Department of Geology, Texas A&M University, College Station, TX 77843-3115 1Present address: Sergent, Hauskins and Beckwith, 4030 S. 500 West, Suite 90, Salt Lake City, UT 84123. Search for other works by this author on: GSW Google Scholar PAUL M. SANTI PAUL M. SANTI Center for Engineering Geosciences, Department of Geology, Texas A&M University, College Station, TX 77843-3115 2Present address: Dames and Moore, 221 Main Street, Suite 600, San Francisco, CA 94105-1917. Search for other works by this author on: GSW Google Scholar Environmental and Engineering Geoscience (1990) xxvii (1): 73–83. https://doi.org/10.2113/gseegeosci.xxvii.1.73 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation CHRISTOPHER C. MATHEWSON, JEFFREY R. KEATON, PAUL M. SANTI; Role of Bedrock Ground Water in the Initiation of Debris Flows and Sustained Post-Flow Stream Discharge. Environmental and Engineering Geoscience 1990;; xxvii (1): 73–83. doi: https://doi.org/10.2113/gseegeosci.xxvii.1.73 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyEnvironmental and Engineering Geoscience Search Advanced Search Abstract Numerous debris-flow events occurred along the Wasatch Front near Salt Lake City, Utah, during the springs of 1983 and 1984. These flows were distinctly different from the previous damaging flows of 1923 and 1930 which were related to cloudburst thunderstorms. The 1983 and 1984 flows were related to the rapid melting of an above average snow pack. These flows originated as localized failures of colluvial sediment on the upper slopes of the Wasatch Front which had developed on a Precambrian metamorphic bedrock. Following the debris-flow event, "normally dry streams" continued to flow well into the autumn. These sustained flows suggest drainage of a ground-water reservoir, "tapped" by the slope failure and scour of the channel. The supply of ground water contained within the colluvium could not sustain the observed stream flow at the canyon mouth. Therefore, we believe that a bedrock reservoir provided the source of water for sustained stream discharges. Field observations and mapping indicate that the metamorphic bedrock has been highly fractured. Erosion control and range management practices following the 1930 debris-flow events combined with a gradual recovery of the Salt Lake area moisture balance effectively recharged this bedrock aquifer. Excess recharge during the rapid spring melt overcharged the bedrock aquifer, increased the pore-water pressure in the colluvium at locations of bedrock springs and seeps, and led to localized slope failures which mobilized the down canyon colluvium into debris flows. Drainage of the bedrock aquifer, at exposed springs and seeps, maintains the sustained stream discharge seen at the canyon mouths. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.