+ Site Statistics
References:
52,654,530
Abstracts:
29,560,856
PMIDs:
28,072,755
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn

+ Translate
+ Recently Requested

Influence of large woody debris on channel morphology and dynamics in steep, boulder-rich mountain streams, western Cascades, Oregon



Influence of large woody debris on channel morphology and dynamics in steep, boulder-rich mountain streams, western Cascades, Oregon



Geomorphology 51(1-3): 187-205



This study used 20-year records of stream channel change and wood to test hypotheses about the long-term influence of large woody debris (LWD) on channel morphology, channel stability, and sediment dynamics in a steep, boulder-rich mountain stream. We compared two nearly adjacent reaches of third-order Mack Creek over the period 1978-1997 after virtually all wood was removed from the channel of the lower reach in 1964. We assessed the long-term legacy of wood removal using repeated cross-section surveys, streamflow data, LWD inventory data, and detailed mapping and longitudinal profile surveys. At each of 11 cross sections in the upper reach and 19 in the lower reach, we calculated areas of scour and fill in response to the two largest floods in the record. We used quasi-likelihood logistic regression models to test the proportion of each reach that experienced change between consecutive surveys over the entire record (1978-1997) as a function of flood return periods. The longitudinal profile of the site without LWD was more variable than the reach with LWD at the finest scale ( approximately 1 m) due to a greater frequency of boulder steps, but the reach with LWD was more variable at the channel unit scale. LWD-created steps 1 to 2.5 m high in the wood-rich reach accounted for nearly 30% of the total channel fall and created low-gradient upstream channel segments one to three channel widths long. As a result, both reaches have the same average slope (about 9%), but nearly three times as much of the channel in the wood-rich reach had a slope of < or =5% as in the reach without wood (20.4% of total channel length vs. 7.5% of channel length). The reach with abundant LWD was less responsive to moderate streamflow events (return period < approximately 5 years), but it responded similarly to peak flows with a return period of about 10 to 25 years. Although the average magnitude of cross-section changes was the same during the largest flood in the record (25-year return period), the reach without LWD experienced scour and coarsening of the bed surface, whereas the reach with LWD experienced aggradation upstream of LWD features. Mack Creek may be representative of many steep mountain streams in which channel structure is strongly influenced by nonfluvial processes: a legacy of large boulders from glacial or mass movement processes and a legacy of dead wood from ecological processes. Sediment-limited mountain streams with large boulders, when deprived of LWD, appear to exhibit less morphological variation at the channel unit scale, to store less sediment, and to release it more readily than those with LWD.

(PDF emailed within 0-6 h: $19.90)

Accession: 018449831

Download citation: RISBibTeXText

DOI: 10.1016/s0169-555x(02)00336-7



Related references

Interaction between woody debris and channel morphology; insights from spring-fed streams in the Oregon Cascades. Abstracts with Programs - Geological Society of America 34(5): 89, 2002

Relationships of channel characteristics, land ownership, and land use patterns to large woody debris in western Oregon streams. Canadian Journal of Fisheries and Aquatic Sciences 59(5): 796-807, 2002

Influence of large woody debris on channel morphology in native forest and pine plantation streams in the Nelson region, New Zealand. New Zealand Journal of Marine and Freshwater Research 36(4): 763-774, 2002

Flood and debris flow interactions with roads promote the invasion of exotic plants along steep mountain streams, western Oregon. Geomorphology 78(1-2): 107-123, 2006

Morphology and processes of valley floors in mountain streams, western Cascades, Oregon. Geophysical Monograph 89: 83-101, 1995

River profile controls on channel morphology, debris flow disturbance, and the spatial extent of salmonids in steep mountain streams. Journal of Geophysical Research: Earth Surface 117(F4), 2012

Physical aquatic habitat II. Pools and cover affected by large woody debris in three Western Oregon streams. North American Journal of Fisheries Management 22(1): 151-164, February, 2002

Effects of coarse woody debris on morphology and sediment storage of a mountain stream in western Oregon. Chikei = Transactions - Japanese Geomorphological Union 13(3): 234, 1992

Density and size of juvenile salmonids in response to placement of large woody debris in western Oregon and Washington streams. Canadian Journal of Fisheries and Aquatic Sciences ruary; 58(2): 282-292, 2001

Effects of coarse woody debris on morphology and sediment storage of a mountain stream system in western Oregon. Earth Surface Processes and Landforms 18(1): 43-61, 1993

Influence of large woody debris on the morphology of six central European streams. Geomorphology 51(1-3): 207-223, 2003

Flow resistance of large woody debris in headwater streams of the Washington Cascades. Abstracts with Programs - Geological Society of America 29(6): 315, 1997

Influence of large boulders on channel morphology and sediment transport in boulder-bed streams, near Santa Barbara, CA. Abstracts with Programs - Geological Society of America 35(4): 3-4, 2003

Effects of 1997 debris floods in two Klamath Mountain streams; a large woody debris mass-balance approach. Eos, Transactions, American Geophysical Union 81(48, Suppl, 2000

The imprint of coarse woody debris on soil chemistry in the western Oregon Cascades. Biogeochemistry 71(2): 163-175, 2004