Long-term sand supply to Coachella Valley Fringe-toed Lizard Habitat in the Northern Coachella Valley, California

2002 ◽  
Keyword(s):  
Coachella Valley ◽  
Sand Supply

scholarly journals MODELING LONG-TERM BEACH CHANGE UNDER INTERACTING LONGSHORE AND CROSS-SHORE PROCESSES

2011 ◽  
Vol 1 (32) ◽  
pp. 62
Author(s):  
Hans Hanson ◽  
Magnus Larson ◽  
Nicholas C Kraus
Keyword(s):  
New York ◽  
Numerical Model ◽  
Model Performance ◽  
Sand Transport ◽  
Shoreline Position ◽  
Coupled Equations ◽  
Sand Supply ◽  
Sensitivity Tests ◽  
Improve Reliability

This paper presents mathematical formulations and a new numerical model GenCade that simulates beach and dune change in response to cross-shore processes of dune growth by wind and dune erosion by storms, and by gradients in longshore sand transport that will also alter shoreline position. The berm plays a central role since the potential for sand to be transported to the dune by wind depends on berm width, and sand lost in erosion of the dune during storms will widen the berm. Morphologic equilibrium considerations are introduced to improve reliability of predictions and stability of the non-linear model. An analytical solution is given to illustrate properties of the model under simplified conditions. Sensitivity tests with the numerical solution of the coupled equations demonstrate model performance. Finally, the numerical model is applied to examine the consequences of groin shortening at Westhampton Beach, Long Island, New York, as an alternative for providing a sand supply to the down-drift beach. Results indicate that the sand will be released over several decades as the shoreline and dune move landward in adjustment to the new equilibrium condition with the shortened groins.

scholarly journals LONG-TERM SHORELINE CHANGES ON MARGINAL COAST OF TIDAL FLAT IN TOKYO BAY AND RAPID DEFORMATION OF SAND BARS OWING TO TSUNAMI

2017 ◽  
pp. 1
Author(s):  
Yasumitsu Mikami
Keyword(s):  
Tidal Flat ◽  
River Mouth ◽  
Aerial Photographs ◽  
Tokyo Bay ◽  
Shoreline Changes ◽  
The North ◽  
Sand Bars ◽  
Sand Supply ◽  
Rapid Deformation

Long-term shoreline changes on the marginal coast of the Banzu tidal flat in Tokyo Bay were investigated using aerial photographs. In the area immediately north of the Obitsu River mouth, the beach was eroded owing to the decrease in sand supply from the river, resulting in the exposure of a layer composed of cohesive material in the previous tidal flat, and sand was transported northward to form a sand spit at the mouth of the north tributary. In 2011, the giant tsunami generated by the Great East Japan Earthquake propagated deep into Tokyo Bay, and sand bars were pushed landward by 7 m parallel to the shoreline owing to the tsunami overflow.

scholarly journals Damage to Seisho Bypass due to Storm Waves During Typhoon 0709

2008 ◽  
Vol 3 (5) ◽  
pp. 342-350 ◽  
Author(s):  
Takaaki Uda ◽  
◽  
Toshiro San-nami ◽  
Toshinori Ishikawa ◽  
Keyword(s):  
Submarine Canyon ◽  
Sand Transport ◽  
Field Observations ◽  
Wave Impact ◽  
The Road ◽  
Storm Waves ◽  
Sand Supply

Some 1.1 km of the Seisho Bypass along the Seisho coast was severely damaged on September 7, 2007, due to Typhoon 0709 storm waves, closing the road to traffic for emergency repairs. Damage to the highway, caused primarily through wave impact and secondarily by long-term shoreline recession due to decreased fluvial sand supply from the Sakawa River and sand loss into a submarine canyon, was investigated through field observations. A factor contributing further to shoreline recession was the obstruction of eastward longshore sand transport by the Ninomiya fishing port breakwater. Storm waves hit the coastline counterclockwise to normal to the shoreline, causing offshore and westward longshore sand transport with part of the sand transported by the longshore sand transport flowing into the submarine canyon, causing a net sand loss.

scholarly journals Origins of The Santa Maria And Vandenberg Coastal Dune Sheets (~100-0 ka) Under Changing Sea Levels, Shoreline Orientations and Wave Directions: Long-Term Records of Coastal Sand Supply in South-Central California, USA

2017 ◽  
Vol 10 (1) ◽  
pp. 33 ◽  
Author(s):  
Curt D Peterson ◽  
Christopher Ryan ◽  
Jack Meyer ◽  
David Price ◽  
Steve W Hostetler
Keyword(s):  
Late Pleistocene ◽  
Coastal Dune ◽  
Beach Erosion ◽  
Dune Sand ◽  
South Central ◽  
Sand Supply ◽  
Coastal Sand ◽  
Santa Maria ◽  
Sand Deposition

Two large coastal dune sheets, including the Santa Maria dune sheet and Vandenberg dune sheet, have been analyzed for late-Quaternary distributions, ages and volumes of dune sand deposition. Six new thermoluminescence (TL) ages establish the age range of dune sand deposition from >106±21 ka to <4.1 ka in the study area. Seven late-Pleistocene TL and 14C dated mid-depth samples (≤30 m depth subsurface), yield a mean of 33 ka for the late-Pleistocene dune deposits. Both TL and 14C dated Holocene dune deposits establish a transition from weathered middle-Holocene dune deposits to unweathered latest-Holocene dune deposits after 4 ka. Marine sand supply to the large dune sheets occurred by 1) cross-shelf eolian transport during late-Pleistocene marine low-stands (70–13 ka), 2) shoreward wave transport during slowing of the Holocene marine transgression (9–5 ka), and 3) longshore littoral transport during the latest-Holocene marine high-sand (3.5–0 ka). Measured and dated dune deposit sections (n=66, ranging from 2 to 60 m depth) demonstrate substantial differences in preserved sand volumes between the two adjacent dune sheets, Santa Maria (~ 2,300x106 m3) and Vandenberg (~430x106 m3). Asymmetric distributions of dune deposit volumes between and within the dune sheets show that long-term sand supply was locally controlled by paleo-shoreline orientations relative to corresponding deep-water wave propagation directions (260–290° TN) from the North Pacific Low Pressure Area. Recently declining sand supplies and/or -trapping efficiencies in the dune sheet littoral subcells led to ongoing shoreline retreat (≥ 200 m) and under-cutting of late- Holocene eolian sand ramps at the south ends of the Santa Maria and Vandenberg dune sheets. The termination of transgressive cross-shelf sand supply and locally variable longshore retention of littoral sand confirm previously reported framework models of regional coastal sand supply. Such models help to identify shorelines that are most susceptible to future beach erosion from predicted sea level rise following ongoing global warming. 

scholarly journals LONG-TERM TOPOGRAPHIC CHANGES AROUND SAND SPIT AND IMPACT OF EXTRAORDINARY HIGH WAVES DURING TYPHOONS

2017 ◽  
pp. 8
Author(s):  
Toshiro San-nami ◽  
Takaaki Uda ◽  
Masashi Yamada ◽  
Toshinori Ishikawa
Keyword(s):  
Deep Sea ◽  
Field Data ◽  
Beach Nourishment ◽  
Steep Slope ◽  
Beach Erosion ◽  
Suruga Bay ◽  
Sand Supply ◽  
Sand Spit ◽  
Long Time

Around the Mihono-matsubara sand spit in Suruga Bay in Japan, the beach was eroded owing to the decrease in the fluvial sand supply from the Abe River triggered by excess riverbed mining before 1967, together with the discharge of sand into the deep sea via a steep slope near the tip of the sand spit. As a measure against beach erosion, an artificial headland (HL) composed of two detached breakwaters and the breakwaters (BWs) placed along the shoreline have been constructed along with beach nourishment, but the beach is barely maintained by these measures. In 2013, two large typhoons hit the coast, causing rapid beach changes around the structures, and these beach changes were superimposed on the long-term topographic changes that have occurred over a long time as a geomorphological process. In this study, their impact to the beaches was investigated on the basis of the field data.

scholarly journals PREDICTION OF BEACH EROSION CAUSED BY REDUCTION OF FLUVIAL SAND SUPPLY DUE TO EXCESS SAND MINING AND BEACH RECOVERY AFTER PROHIBITION OF MINING

2012 ◽  
Vol 1 (33) ◽  
pp. 61 ◽  
Author(s):  
Toshiro San-nami ◽  
Takaaki Uda ◽  
Norikazu Ohashi ◽  
Hitoshi Iwamoto ◽  
Masumi Serizawa ◽  
...  
Keyword(s):  
River Mouth ◽  
Sediment Supply ◽  
Beach Erosion ◽  
Sand Mining ◽  
Natural Sand ◽  
Sand Supply ◽  
Sand Body ◽  
Bathymetric Changes ◽  
Good Agreement

Long-term topographic changes since 1968 along the entire Shizuoka and Shimizu coasts including a 17 km stretch extending between the Abe River mouth and the tip of the Mihono-matsubara sand spit were investigated. Beach erosion of these coasts was triggered by the decrease in sediment supply from the Abe River due to excessive riverbed mining until 1967. After 1982/1983, natural sand supply from the river increased and accretion occurred on these coasts. Measured topographic changes were reproduced using the contour-line-change model considering changes in grain size. Not only the movement of the sand body but also the shoreline and bathymetric changes were numerically reproduced. The calculated results were in good agreement with the measured topographic changes.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

Sign in / Sign up

Export Citation Format

Share Document