Observations of Downstream Fining on the North Fork Toutle River Near Mount St. Helens, Washington

1995 ◽  
Vol 31 (5) ◽  
pp. 1409-1419 ◽  
Author(s):  
Rebecca Seal ◽  
Chris Paola

<em>Abstract</em>—The North Fork Toutle River drains the northwest face of Mount St. Helens to the Cowlitz River, a major tributary of the Columbia River in southwestern Washington. In response to the 1980 eruption of Mount St. Helens, the U.S. Army Corps of Engineers constructed a sediment retention structure (SRS) in the North Fork Toutle River watershed to reduce the transport of fine sediment to the lower Cowlitz and Columbia River systems. The SRS was built without fish passage facilities and currently presents a significant barrier to migrating adult salmonids. To facilitate passage of coho salmon <em>Oncorhynchus kisutch </em>and steelhead <em>O. mykiss </em>to the upper watershed, a fish collection facility (FCF) was constructed 1.5 km downstream of the SRS, where fish are currently captured and transported to tributaries upstream of the SRS. We used radio telemetry to evaluate the movement of adult coho salmon and steelhead in the North Fork Toutle River in 2005 and 2006. A total of 40 coho and 42 steelhead were released from four different release sites in varied proportions. Release sites included the FCF, the SRS, and Alder Creek and Hoffstadt Creek, both North Fork Toutle River tributaries upstream of the SRS. Results from this research effort suggest that (1) unlike adult coho, adult steelhead are able to ascend the SRS spillway; (2) upstream adult coho and steelhead passage through the sediment plain is possible but may be flow-dependent; (3) adult coho and steelhead released in Alder Creek and Hoffstadt Creek tend to remain within their respective release tributary; and (4) postspawn steelhead emigration is limited. Future research is required to adequately address factors that influence movement of adult coho and steelhead in the upper North Fork Toutle River. The information resulting from this collaborative effort is enabling natural resource managers to determine whether the SRS spillway is a barrier to anadromous fish, to refine existing trap and haul operations, or, if appropriate, to consider modifying the spillway to enable volitional passage by upstream-migrating fish.


Geomorphology ◽  
2014 ◽  
Vol 208 ◽  
pp. 102-116 ◽  
Author(s):  
Shan Zheng ◽  
Baosheng Wu ◽  
Colin R. Thorne ◽  
Andrew Simon

2007 ◽  
Vol 40 (3) ◽  
pp. 229-238 ◽  
Author(s):  
James F. P. Cotter ◽  
James M. Bloomfield ◽  
Edward B. Evenson

ABSTRACT Glacial and glaciofluvial deposits are mapped and differentiated to develop new local, relative-age (RD) stratigraphies for the North Fork of the Big Lost River, Slate Creek and Pole Creek drainages in the White Cloud Peaks and Boulder Mountains, Idaho. This stratigraphic model expands the areal extent of the "Idaho glacial model". Volcanic ash samples collected from the study area are petrographically characterized and correlated, on the basis of mineralogy and glass geochemistry, to reference samples of identified Cascade Range tephras. Four distinct tephras are recognized including; Mount St. Helens-Set S (13,600-13,300 yr BP), Glacier Peak-Set B (11,250 yr BP), Mount Mazama (6600 yr BP) and Mount St. Helens-Set Ye (4350 yr BP). A core of lake sediments containing two tephra units was obtained from a site called "Pole Creek kettle". Pollen and sediment analyses indicate three intervals of late Pleistocene and Holocene climatic change. Cool and wet climatic conditions prevailed in the region shortly before and immediately following the deposition of the Glacier Peak-Set B ash (11,250 yr BP). Climatic warming occurred from approximately 10,500 to 6600 yr BP after which warm, dry conditions prevailed. Sediment accumulation in the kettle ceased by 4350 yr BP. The presence of Glacier Peak-Set B tephra in the base of the Pole Creek kettle core provides a minimum age of 11,250 yr BP for the retreat of valley glaciers from their Late Wisconsinan maximum position. A radiocarbon date of 8450 + 85 yr BP (SI-5181), and the presence of Mount Mazama ash (6600 yr BP) up-core support the Glacier Peak-Set B identification.


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