Arc versus river—The geology of the Columbia River Gorge

2021 ◽  
pp. 131-186 ◽  
Author(s):  
Jim E. O’Connor* ◽  
Ray E. Wells* ◽  
Scott E.K. Bennett* ◽  
Charles M. Cannon* ◽  
Lydia M. Staisch* ◽  
...  

ABSTRACT The Columbia River Gorge is the Columbia River’s long-held yet evolving passage through the volcanic arc of the Cascade Range. The globally unique setting of a continental-scale river bisecting an active volcanic arc at the leading edge of a major plate boundary creates a remarkable setting where dynamic volcanic and tectonic processes interact with diverse and energetic fluvial processes. This three-day field trip explores several elements of the gorge and its remarkable geologic history—cast here as a contest between regional tectonic and volcanic processes building and displacing landscapes, and the relentless power of the Columbia River striving to maintain a smooth passage to the sea. DEDICATION Dedicated to Russell C. Evarts (7 April 1947–11 July 2017) and his contributions to Pacific Northwest geology. Russ Evarts devoted most of his 30-year career with the U.S. Geological Survey to geologic mapping of Oregon and Washington. His thorough geologic mapping of the near-vertical terrain of the western Columbia River Gorge underpins much of what is reported in this guide and continues to inspire our studies of the geology of the Pacific Northwest.

1992 ◽  
Vol 37 (1) ◽  
pp. 42-59 ◽  
Author(s):  
James C. Chatters ◽  
Karin A. Hoover

AbstractAn understanding of the response of a fluvial system to past climatic changes is useful for predicting its response to future shifts in temperature and precipitation. To determine the response of the Columbia River system to previous climatic conditions and transitions, a well-dated sequence of floodplain development in the Wells Reservoir region was compared with the paleoenvironmental history of the Columbia River Basin. Results of this comparison indicate that aggradation episodes, occurring approximately 9000-8000, 7000-6500, 4400-3900, and 2400-1800 yr B.P., coincided with climatic transitions that share certain characteristics. The inferred climates associated with aggradation had at least moderate rates of precipitation that occurred mainly in winter coupled with moderate winter temperatures. Such conditions would have resulted in the buildup of snowpacks and a high frequency of rain-on-snow events. The warming and precipitation increases predicted for the Pacific Northwest under most CO2-doubling scenarios are likely to repeat these conditions, which could increase the frequency of severe, sediment-laden floods in the Columbia River Basin.


2012 ◽  
Vol 1 (33) ◽  
pp. 53 ◽  
Author(s):  
Sarah Kassem ◽  
H. Tuba Ozkan-Haller

An operational wave forecast of the area near the mouth of the Columbia River is presented. This region is known for its large waves and strong tidal currents. The forecast is forced with full directional spectra obtained from a refined WaveWatchIII forecast of the Pacific Northwest, and tidal current inputs are obtained from an estuarine circulation forecast of the Columbia River. The forecast has been operational since August 2011 providing short-term predictive wave information at the mouth of the Columbia River. Results from a 6-month period are promising, with a normalized root-mean-squared error (NRMSE) of 16% at the location of an inshore buoy, which is located outside the zone of tidal influence in 25 m water depth. Near the river mouth and in the channel, wave heights are heavily dominated by the tidal currents which significantly increase wave heights on ebb tides. Hindcast results shows that the model is able to predict the general effect of the tidal currents with a NRMSE of 30% in wave heights at the river mouth. Despite some of the model limitations, it still provides valuable information to navigators and bar pilots since it includes the effects of the tidal currents.


2009 ◽  
Vol 9 (3) ◽  
pp. 14235-14261 ◽  
Author(s):  
D. A. Jaffe ◽  
D. R. Reidmiller

Abstract. We have analyzed 14 years of aerosol data spanning 1993–2006 from the IMPROVE site at Wishram, Washington (45.66° N, 121.00° W; 178 m above sea level) in the Columbia River Gorge (CRG) National Scenic Area (http://www.fs.fed.us/r6/columbia/) of the Pacific Northwest of the US. Two types of analyses were conducted. First, we examined the transport for days with the highest fine mass concentrations (particulate matter with diameter <2.5μm or, PM2.5) using HYSPLIT back-trajectories. We found that the highest PM2.5 concentrations occurred during autumn and were associated with easterly flow, down the CRG. Such flow transports emissions from a large coal power plant and a large agricultural facility into the CRG. This transport was found on 20 out of the 50 worst PM2.5 days and resulted in an average daily concentration of 20.1 μg/m3, compared with an average of 18.8 μg/m3 for the 50 highest days and 5.9 μg/m3 for all days. These airmasses contain not only high PM2.5 concentrations but also elevated aerosol NO3− concentrations. These results suggest that emissions from large industrial and agricultural sources on the east end of the CRG, including the coal-fired power plant at Boardman, Oregon, have a significant impact on air quality in the region. In the second analysis, we examined PM2.5 concentrations in the CRG during periods when the Boardman power plant was shut down due to repairs and compared these values with concentrations when the facility was operating at near full capacity. We also examined this relationship on the days when trajectories suggested the greatest influence from the power plant on air quality in the CRG. From this analysis, we found significantly higher PM concentrations when the power plant was operating at or near full capacity. We use these data to calculate that the contribution to PM2.5 mass in the CRG from the Boardman plant was 0.90 μg/m3 averaged over the entire year, 3.94 μg/m3 if only the month of November is considered and 7.40 ug/m3 if only November days when the airflow is "down-gorge" (from east to west). This represents 15–56% of PM2.5 mass in the CRG. In all 3 cases the difference in PM2.5 concentrations are statistically significant at a >95% confidence interval for the comparison of normal plant emissions vs shutdown conditions. We, therefore, find that the coal-fired power plant at Boardman, Oregon is a significant contributor to PM2.5 concentrations in the CRG.


2016 ◽  
Vol 52 (5) ◽  
pp. 1121-1141 ◽  
Author(s):  
Jeremy S. Littell ◽  
Gregory T. Pederson ◽  
Stephen T. Gray ◽  
Michael Tjoelker ◽  
Alan F. Hamlet ◽  
...  

Author(s):  
Douglas C. Wilson ◽  
Kenneth M. Ames ◽  
Cameron M. Smith

Employing an indigenous-centered perspective, this chapter explores the impact of material objects recovered from houses, hearths, and camp facilities received by the Chinook (at the mouth of the Columbia River in the Pacific Northwest of North America) as gifts, purchased, used, modified, repaired and discarded. These materials come from the Middle Village (qí’qayaqilxam) component of the Station Camp/McGowan site (45PC106), a traditional summer village occupied recurrently by hunter-gatherer-fishers during the early fur-trade period (ca. A.D. 1788-1825). The manner in which new forms of capital, like glass trade beads, muskets, European and Chinese ceramics, copper and iron goods, and glass bottles, were integrated into Chinook economic and political systems is important in the study of colonialism and culture contact. Combined with ethnographic and ethnohistorical data, their use is contextualized within dramatic social and demographic changes in Chinook culture as it intersected with British and American commercial trade.


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