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Full-Text Articles in Geography
Soil Properties And Behavior Of Earthflows In The Mt. Hood National Forest, Oregon, Douglas Andrew Smith
Soil Properties And Behavior Of Earthflows In The Mt. Hood National Forest, Oregon, Douglas Andrew Smith
Dissertations and Theses
Soils from two active earthflows, two earthflow deposits, and three non-earthflow landforms are examined to determine if a connection exists between near-surface soil properties and rates of earthflow movement. The study area is located in the Clackamas Ranger District of the Mt. Hood National Forest in the northern Oregon Cascades. Its geology consists of clay-bearing volcaniclastic formations overlain by unaltered flows of andesite and basalt, a combination that contributed to large-scale landsliding during the late Pleistocene. Deposits from these landslides now cover much of the valley floor, and it is from these deposits that earthflows tend to mobilize. The main …
An Assessment Of The Riparian-Influenced Salmonid Habitat Features Of Johnson Creek, Portland, Oregon, Andrew Greiff Gude
An Assessment Of The Riparian-Influenced Salmonid Habitat Features Of Johnson Creek, Portland, Oregon, Andrew Greiff Gude
Dissertations and Theses
Pacific salmon populations in Johnson Creek, Portland, Oregon have been adversely impacted by urbanization, and by residential and agricultural land development. Ecological impacts include loss or depletion of riparian vegetation features which directly influence stream and associated salmonid ecology. This research examines the nearstream riparian zone's contribution to instream habitat complexity for anadromous salmonids in Johnson Creek. Visual surveys were conducted on over half the stream length. Five features were assessed to determine the extent of riparian influenced stream habitat including, overhead enclosure, overhanging vegetation, undercut banks, and large and small woody debris and root wads. The stream survey showed …