Bayocean sand spit lies along the northern Oregon coast
approximately 70 miles south of the Columbia River. Work was
begun on the construction of a large recreational resort on the spit
in the early 1900's. At the outset, the resort appeared to have a
promising future. However, a three-year delay...
Siletz Bay is a drowned river valley filled with Holocene alluvial
and estuarine sediments and is separated from the ocean by a sand
spit 3.8 km in length. Since the area was settled by white man in the
1890's, the bay has apparently experienced rapid siltation, due to
increased farming...
Patterns of beach erosion and accretion due to jetty construction
are examined for the coast of Oregon. All jetty systems are
included with the exception of those on the Columbia River, making a
total of nine systems.
All evidence indicates that these areas of the Oregon coast are
experiencing a...
Tillamook Bay is the second largest estuary on the Oregon coast, and concerns have been raised whether human induced impacts have been responsible for the perceived increase in sedimentation rates during the past century. Major land-use practices within the five watersheds of the Bay include logging, forest fires, the construction...
Theoretical b:::-eaking criteria for progressive surface gravity waves
are examined, and laboratory and field experiments concerned with breaking waves are reviewed with respect to the testing of these breaking criteria.
The measurements of Komar and Simmons are presented here for the first
time. Only three theoretical breaking criteria have been...
The Port of Astoria has proposed to fill a 32.4 hectare inter- and
subtidal area at the mouth of Youngs Bay, Columbia River, Oregon. The
possible effects of this fill on the biota and sedimentation patterns
of this area were studied from 31 August 1975 to 29 February 1976. Part...
Theoretical breaking criteria for progressive surface gravity
waves are examined, and laboratory and field experiments concerned
with breaking waves are reviewed with respect to the testing of these
breaking criteria. The measurements of Komar and Simmons are
presented here for the first time. Only three theoretical breaking
criteria have been...
During the period 1970-76, Siletz Spit on the mid-Oregon coast
has suffered foredune erosion. This erosion is associated with high
wave conditions along the coast, produced by intense storms in the
North Pacific.
During the winter of 1972-73 and during January through March
1976 the erosion was particularly severe. The...
Two beaches with significant differences in grain size and thus in beach profile morphology and response to wave conditions were studied on the Oregon coast. Gleneden Beach, just south of Siletz Spit and Lincoln City, has a median grain size of 0.36 mm (medium sand) and a steep beach face...
Heavy mineral compositions of sands from Oregon beaches,
rivers and sea cliffs have been determined in order to examine the
causes of marked along-coast variations in the beach-sand
mineralogy. The study area extends southward from the Columbia
River to the Coquille River in southern Oregon. The heavy-mineral
compositions were determined...
Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. This study examines shoreline erosion in Flathead Lake, Montana due to five decades of artificially elevated lake levels. It provides a model to investigate coastal erosion associated with sea-level rise. The natural water...
Straight, radial, erosional channels and fan-like deposits of tephra develop around steep-sided cones and composite volcanoes, but are not characteristic features of shield volcanoes. The channels and deposits normally are formed by explosive volcanic density currents which originate as nuées adrentes or base surges. The physical processes of explosive volcanic...
Field observations are made of the formation of backwash ripples
on the beachface, formed by undular hydraulic jumps generated by backwash
down the beach face colliding with wave bores. Measured ripple
wavelengths range from set averages of 48 to 70 cm. Within a particular
set of ripples there is a...