2,897 research outputs found

    Infrared testing of electronic components Final report, 5 Apr. 1965 - 5 Jun. 1966

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    Infrared radiation nondestructive test technique for electrical/electronic equipmen

    Sediment impacts from the Savage Rapids Dam removal

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    ABSTRACT Before a dam removal project is implemented, engineers are often asked to estimate the potential for impacts from the release of reservoir sediment. Field measurements, numerical models, and physical models are typically used to develop sediment impact estimates. This information helps decision makers to make informed decisions about when and how to remove the dam, whether to allow the river to erode the reservoir sediment, or to remove or stabilize the reservoir sediment prior to dam removal, or whether mitigation of the effects is needed. Although numerous dams have been removed, mostly small in size, few case studies on sediment impacts have been documented. Because there are limited case studies, dam removal regulators and stakeholders often err on the side of caution when selecting the level of pre removal analysis or determining whether the reservoir sediment needs to be removed prior to dam removal. The purpose of this paper is to increase our knowledge base for application to future dam removals. The chapter discusses sediment impacts associated with the removal of the 11.9-m-high Savage Rapids Dam on the Rogue River near Grants Pass, Oregon. A unique factor to the Savage Rapids project was the construction and operation of a new diversion facility and water intake located immediately downstream of the dam, which introduced additional consequences associated with the release of reservoir sediment

    Population characteristics of Shovelnose Sturgeon during low- and high-water conditions in the lower Platte River, Nebraska

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    Cycles of low- and high-water periods (i.e., years) in river systems are natural occurrences, but understanding how cyclical climatological patterns affect fishes, especially long-lived species, is unclear. We assessed Shovelnose Sturgeon population dynamics between a period of low- (2001-2004) and high- (2009-2012) water years in the lower Platte River, Nebraska. Low-flow periods in the lower Platte River can cause disconnection(s) between upstream and downstream reaches resulting in isolated pools and elevated water temperatures leading to stressful situations for aquatic life and possible mortality. Our data show no measurable differences between key population indices between flow condition periods which is consistent with current paradigms for long-lived fish species. Shovelnose Sturgeon relative weights were generally \u3e 80 during both low- and high-water periods and the size structure did not differ between the two periods. Shovelnose Sturgeon abundances, however, were greater during high-water conditions compared to low-water conditions (Kruskal-Wallis: χ2 = 6.15, d.f. = 1, P = 0.01). Shovelnose Sturgeon may have migrated to more suitable habitats during low-water periods to seek refuge allowing these individuals to return during more suitable conditions. Shovelnose Sturgeon and other riverine fish have evolved in a variable environment and have been able to endure relatively minor anthropogenic changes within the lower Platte River. Rivers like the lower Platte River that have retained much of their original physical features and flow regimes are likely key components for the resistance and resilience of riverine species. However, as alterations to landscapes continue and uncertainty exists surrounding future climate predictions, it is unknown how these riverine species will be able to adapt to future changes. The reduction in anthropogenic changes that disrupt flow regimes and increasing connectivity among river systems could provide more fish refuge during stressful conditions helping to protect these riverine species
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