Downstream Effects of the Pelton-Round Butte Hydroelectric Project on Bedload Transport, Channel Morphology, and Channel-Bed Texture, Lower Deschutes River, Oregon

2013 ◽  
pp. 169-201 ◽  
Author(s):  
Heidi Fassnacht ◽  
Ellen M. Mcclure ◽  
Gordon E. Grant ◽  
Peter C. Klingeman
Keyword(s):  
Channel Morphology ◽  
Bedload Transport ◽  
Transport Channel ◽  
Hydroelectric Project ◽  
Downstream Effects ◽  
Deschutes River

Effects of episodic sediment supply on experimental step-pool channel morphology, bedload transport and channel stability

2021 ◽  
Author(s):  
Jiamei Wang ◽  
Marwan A. Hassan ◽  
Matteo Saletti ◽  
Xingyu Chen ◽  
Xudong Fu ◽  
...  
Keyword(s):  
Grain Size ◽  
Morphological Changes ◽  
Mass Movement ◽  
Channel Morphology ◽  
Bedload Transport ◽  
Sediment Supply ◽  
Primary Control ◽  
Channel Stability ◽  
Flume Experiments ◽  
Small Magnitude

<p>Steep step-pool streams are often coupled to adjacent hillslope, directly receiving episodic sediment supply from mass movement processes such as landslides and debris flows. The response of step-pool channels to the variations in sediment supply remains largely unexplored. We conducted flume experiments with a poorly sorted grain-size distribution in an 8%-steep, 5-m long flume with variable width at the University of British Columbia, to study the effects of episodic sediment supply on channel evolution. After a conditioning phase with no feed, the channel was subjected to sediment pulses of different magnitude and frequency under constant flow discharge. High-resolution data of hydraulics, bedload transport, bed surface grain size, and channel morphology were collected every 10-20 minutes and an additional time at the end of each pulse.</p><p>In response to sediment pulses, we recorded an increase in bedload transport rates, channel aggradation, bed surface fining, and continuous step formation and collapse. In between pulses, bedload rates dropped by several orders of magnitude, net erosion occurred, the bed surface gradually coarsened, and steps became more stable. The small-magnitude high-frequency pulses caused smaller but more frequent spikes in bedload transport, bed surface evolution, and thus step stability. Instead, the large-magnitude low-frequency pulses cause larger changes but provided a longer time for the channel to recover. This suggests that in step-pool channels pulse magnitude is a key control on channel rearrangement, while pulse frequency controls how fast and strong the recovery is.</p><p>The frequency and stability of steps varied as a function of local channel width, showing that channel geometry is a primary control on step formation and stability even under episodic sediment supply conditions. Instead, the effect of sediment pulses is less important because the total number and average survival time of steps were similar among runs with different pulses. The critical Shields stress decreased following sediment pulses, then increased immediately after, and fluctuated until the next pulse. The variations in sediment supply caused cycles in bedload transport rate, surface and bedload texture, thus controlling the variability in the threshold for motion.</p><p>Our results indicate that episodic sediment supply is a primary control on the evolution of step-pool channels, with sediment feed magnitude affecting mostly morphological changes, and sediment feed frequency controlling channel stability.</p>

Whirling Disease: Reviews and Current Topics

2002 ◽  
Keyword(s):  
River Basin ◽  
Columbia River ◽  
Fish Populations ◽  
Steelhead Trout ◽  
Adult Fish ◽  
Whirling Disease ◽  
Myxobolus Cerebralis ◽  
Hydroelectric Project ◽  
Natural Production ◽  
Deschutes River

<EM>ABSTRACT. </EM>Anadromous fish were excluded above Pelton Round Butte Hydroelectric Project (PRB Project), located midway (RM 100) on the Deschutes River in central Oregon, beginning in 1968. Reintroduction of these fish above the PRB Project is proposed to meet conservation concerns that arise from lack of natural production and separation of populations. One consideration, when moving fish groups that have been isolated one from the other for thirty years, is that of disease. The health of the fish populations above Round Butte Dam could be seriously jeopardized by the introduction of whirling disease. Straying hatchery steelhead trout <em>Oncorhynchus mykiss </em>were detected with <em>Myxobolus cerebralis </em>spores, in 1987, at Warm Springs National Fish Hatchery, below the PRB Project. <em>Myxobolus cerebralis </em>is established in tributaries of the upper Columbia River basin and of the Snake River basin, where some of these straying hatchery and wild steelhead trout may have originated. From 1997 to 2000, fish from the Deschutes River basin have been sampled for the presence of <em>M. cerebralis</em>. The parasite has been found in both straying hatchery and unmarked adult chinook salmon <em>O. tshawytscha </em>and steelhead trout. Presently there is no evidence of infection of resident fish or in returning adult fish originating from Round Butte Hatchery, although the potential for establishment of <em>M. cerebralis </em>in the Deschutes River watershed cannot be ruled out.

Молекулярная биология менингиом головного мозга

2017 ◽  
pp. 82-91
Author(s):  
В.А. Бывальцев ◽  
И.А. Степанов ◽  
Е.Г. Белых ◽  
А.И. Яруллина
Keyword(s):  
Gene Therapy ◽  
Proton Therapy ◽  
Genetic Factors ◽  
Intracranial Tumor ◽  
Molecular Profile ◽  
Genetic Changes ◽  
Treatment Techniques ◽  
Downstream Effects ◽  
Si Rna ◽  
The Relationship

Цель обзора - анализ современных данных литературы о нарушении внутриклеточных сигнальных путей, играющих ведущую роль в развитии менингиом, генетических и молекулярных профилях данной группы опухолей. К настоящему времени изучено множество аберрантных сигнальных внутриклеточных путей, которые играют важнейшую роль в развитии менингиом головного мозга. Четкое понимание поврежденных внутриклеточных каскадов поможет изучить влияние генетических мутаций и их эффектов на менингиомогенез. Подробное исследование генетического и молекулярного профиля менингиом позволит сделать первый уверенный шаг в разработке более эффективных методов лечения данной группы интракраниальных опухолей. Хромосомы 1, 10, 14, 22 и связанные с ними генные мутации ответственны за рост и прогрессию менингиом. Предполагается, что только через понимание данных генетических повреждений будут реализованы новейшие эффективные методы лечения. Будущая терапия будет включать в себя комбинации таргетных молекулярных агентов, в том числе генную терапию, малые интерферирующие РНК, протонную терапию и другие методы воздействия, как результат дальнейшего изучения генетических и биологических изменений, характерных для менингеальных опухолей. Meningiomas are by far the most common tumors arising from the meninges. A myriad of aberrant signaling pathways involved with meningioma tumorigenesis, have been discovered. Understanding these disrupted pathways will aid in deciphering the relationship between various genetic changes and their downstream effects on meningioma pathogenesis. An understanding of the genetic and molecular profile of meningioma would provide a valuable first step towards developing more effective treatments for this intracranial tumor. Chromosomes 1, 10, 14, 22, their associated genes, have been linked to meningioma proliferation and progression. It is presumed that through an understanding of these genetic factors, more educated meningioma treatment techniques can be implemented. Future therapies will include combinations of targeted molecular agents including gene therapy, si-RNA mediation, proton therapy, and other approaches as a result of continued progress in the understanding of genetic and biological changes associated with meningiomas.

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