Filters: partyWithName: James E O'connor (X)
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This data release provides access to a low-altitude aeromagnetic survey flown over a part of the Cascade Range of the US Pacific Northwest, approximately centered over the town of Cascade Locks, Oregon. The Cascade Locks magnetic survey encompasses two large stratovolcanoes of the Cascade Range: Mt. Hood (3426 m) in Oregon and Mt. Adams (3742 m) in Washington. Data were acquired between October 17, 2021, and February 26, 2022, by KBM Resources Group, Thunder Bay, Ontario, Canada, working under contract to the U.S. Geological Survey. The survey is underlain by a diverse magnetic terrane, including Miocene flood basalts of the Columbia River Basalt Group and Tertiary to Quaternary volcanic and intrusive rocks of the...
Categories: Data;
Tags: Cascade Range,
Cascadia,
Clackamas County,
Clark County,
Columbia River Gorge National Scenic Area,
Forty years ago, the demolition of large dams was mostly fiction, notably plotted in Edward Abbey's novel The Monkey Wrench Gang. Its 1975 publication roughly coincided with the end of large-dam construction in the United States. Since then, dams have been taken down in increasing numbers as they have filled with sediment, become unsafe or inefficient, or otherwise outlived their usefulness ( 1) (see the figure, panel A). Last year's removals of the 64-m-high Glines Canyon Dam and the 32-m-high Elwha Dam in northwestern Washington State were among the largest yet, releasing over 10 million cubic meters of stored sediment. Published studies conducted in conjunction with about 100 U.S. dam removals and at least 26...
Categories: Publication;
Types: Citation
This data release consists of high quality georeferenced orthophoto mosaics of a 160 kilometer long portion of the Columbia River between Portland and The Dalles, Oregon created from aerial photographs collected in 1935 by the U.S. Army Corps of Engineers. The dataset comprises three GeoTIFF files, each covering about 40-60 kilometers. This metadata document summarizes the entire data release. See attached metadata records for information on the individual mosaics.
Recent decades have seen a marked increase in the number of dams removed in the United States. Investigations following a number of removals are beginning to inform how, and how fast, rivers and their ecosystems respond to released sediment. Though only a few tens of studies detail physical responses to removals, common findings have begun to emerge. They include: (1) Rivers are resilient and respond quickly to dam removals, especially when removals are sudden rather than prolonged. Rivers can swiftly evacuate large fractions of reservoir sediment (≥50% within one year), especially when sediment is coarse grained (sand and gravel). The channel downstream typically takes months to years--not decades--to achieve a...
Categories: Publication;
Types: Citation
This dataset represents a variety of scientific measurements of basalt rock outcrops in central Oregon, United States. It consists of field observations, geochemical measurements, paleomagnetic directional measurements, magnetic susceptibility, and geochronology data (Ar-Ar methodology). This dataset was collected from 2014-2022 by the authors.
Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions between physical and ecological aspects of dam removal are poorly known. From recent work, however, observations are now available from several diverse settings nationwide to allow synthesis of key physical and ecological processes associated with dam removals, including fish and benthic community response, reservoir erosion,...
Dam decommissioning is rapidly emerging as an important river restoration strategy in the United States. Hundreds of dams have been removed in the past few decades, including several large ones (>10-15 meters) impounding large sediment volumes (>106 cubic meters) in the past 3 years, notably Condit Dam and the Elwha River dams in Washington State. These removals and the associated studies provide for the first time an opportunity to evaluate the immediate and persistent consequences of these significant fluvial--and in some cases, coastal--perturbations. Understanding dam removal response not only improves understanding of landscape and ecosystem adjustment to profound sediment pulses but also provides important...
Categories: Publication;
Types: Citation
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