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Denver, CO, United States

The United States Bureau of Reclamation , and formerly the United States Reclamation Service , is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and operation of the diversion, delivery, and storage projects that it has built throughout the western United States for irrigation, water supply, and attendant hydroelectric power generation. Currently USBR is the largest wholesaler of water in the country, bringing water to more than 31 million people, and providing one in five Western farmers with irrigation water for 10 million acres of farmland, which produce 60% of the nation's vegetables and 25% of its fruits and nuts. USBR is also the second largest producer of hydroelectric power in the western United States.In July 1902, in accordance with the Reclamation Act, Secretary of the Interior Ethan Allen Hitchcock established the U.S. Reclamation Service within the U.S. Geological Survey . The new Reclamation Service studied potential water development projects in each western state with federal lands—revenue from sale of federal lands was the initial source of the program's funding. Because Texas had no federal lands, it did not become a Reclamation state until 1906, when Congress passed a special Act including it in the provisions of the Reclamation Act. Wikipedia.

Chapman M.,Bureau of Reclamation
Desalination | Year: 2013

High productivity reverse osmosis membrane developed under the Office of Naval Research Expeditionary Unit Water Purification Program was evaluated at the Bureau of Reclamation Brackish Groundwater National Desalination Research Facility (BGNDRF). Performance of the new membrane was evaluated in comparison to two other commercial high productivity or low pressure reverse osmosis membranes using a high productivity test system designed and built to take best advantage of high flux membrane through either lower operating pressure or greater productivity. Membranes were evaluated with brackish groundwater over a range of cross flow velocities and recovery rates. Experimental membrane water transport was approximately twice two to three times that of the commercial membrane and salt transport was an order of magnitude less than commercial membrane at 20% recovery for three modules of four inches by forty inches in series tested at a range of feed flow rates. © 2012. Source

Wiesenborn W.D.,Bureau of Reclamation
Florida Entomologist | Year: 2011

I investigated the contributions of body mass, order, family, and trophic level to nitrogen (N) content in riparian spiders and insects collected near the Colorado River in western Arizona. Most variation (97.2%) in N mass among arthropods was associated with the allometric effects of body mass. Nitrogen mass increased exponentially as body dry-mass increased. Significant variation (20.7%) in N mass adjusted for body mass was explained by arthropod order. Adjusted N mass was highest in Orthoptera, Hymenoptera, Araneae, and Odonata and lowest in Coleoptera. Classifying arthropods by family compared with order did not explain significantly more variation (22.1%) in N content. Herbivore, predator, and detritivore trophic-levels across orders explained little variation (4.3%) in N mass adjusted for body mass. Within orders, N content differed only among trophic levels of Diptera. Adjusted N mass was highest in predaceous flies, intermediate in detritivorous flies, and lowest in phytophagous flies. Nitrogen content in riparian spiders and insects is most dependent on allometry and order and least dependent on trophic level. I suggest the effects of allometry and order are due to exoskeleton thickness and composition. Foraging by vertebrate predators, such as insectivorous birds, may be affected by variation in N content among riparian arthropods. Source

Nelson S.M.,Bureau of Reclamation
International Review of Hydrobiology | Year: 2011

Replacement of native macrophyte species with exotic or invasive ones affects the quality of detritus entering streams and can alter nutrient cycles and community structure in aquatic ecosystems. Decomposition of air-dried native hardstem bulrush (Schoenoplectus acutus), invasive southern cattail (Typha domingensis), and exotic common reed (Phragmites australis) were studied in an urban stream (Las Vegas, Nevada, USA) using litter bags. Samples were analyzed for dry mass, lignin, nutrients, trace elements, and macroinvertebrates. Litter type and sediment deposited on plant material influenced material loss. Trace elements arsenic and selenium increased in plant material to concentrations considered marginal for ecosystem contamination by exposure day 76. Mercury increases were inconsistent across plant species and did not exceed limits. Bulrush decomposed faster, and tended to have higher selenium concentrations, than did invasive southern cattail and exotic common reed. Macroinvertebrate communities colonizing litter bags were similar across plant litter types, but differed from mesh-only bags and samples collected with a kick-net. Macroinvertebrate exclusion resulted in significantly lower loss rates, but functional feeding groups such as shredders were not associated with decomposition differences. The caddisfly, Smicridea, physically modified stem material and aided in processing, but microbes appeared most important in biological material breakdown. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

England Jr. J.F.,Bureau of Reclamation
Australian Journal of Water Resources | Year: 2011

Design flood estimation procedures in the United States have traditionally focused on two primary methods: frequency analysis of peak flows for floodplain management and levee design; and deterministic, probable maximum flood (PMF) estimates for design of dams and nuclear facilities. Federal Agencies in the United States, including the Bureau of Reclamation, US Geological Survey and Army Corps of Engineers, are currently examining potential changes to these standard flood hydrology procedures. This paper presents overviews of some ongoing investigations and data collection studies to support potential changes in design flood estimation. For floodplain management, the current guideline is Bulletin 17B, which specifies the use of an LP3 distribution, method of moments and regional skew information. Potential improvements to Bulletin 17B currently under consideration are: (i) use of historical and paleoflood information; (ii) adjusting for low outliers; (iii) improved plotting positions; and (iv) confidence intervals. Ongoing testing results are presented, highlighting the expected moments algorithm. In contrast to well-established, deterministic (PMF) extreme flood estimates for dam safety, agencies are now moving toward risk-based techniques. The Bureau of Reclamation has developed and applied several methods in order to estimate extreme floods and probabilities for large dams. Techniques used to date are summarised, along with those being considered by other US agencies. Improvements to extreme flood databases that provide inputs, including extreme storms and probable maximum precipitation estimates, precipitation frequency and paleofloods, are ongoing. Some challenges to updating design flood methods and data, including institutional effects, national scale, research to operations and use of new technologies, are described. © Institution of Engineers Australia, 2011. Source

Maier P.L.,Bureau of Reclamation | Durham S.A.,University of Colorado at Denver
Construction and Building Materials | Year: 2012

The need to incorporate recycled materials in building products is becoming more important than ever before. The use of recycled materials in concrete mixtures creates landfill avoidance and decreases the depletion of virgin raw materials. The basis for this research was to investigate the effects of using recycled materials, in varying amounts, on the fresh and hardened concrete properties. The recycled materials used in this study consisted of ground granulated blast furnace slag (GGBFS), recycled concrete aggregate (RCA) and crushed waste glass. The GGBFS, or slag cement, was used as a replacement for the cement. The RCA and waste glass were used to replace the coarse and fine aggregates, respectively. The concrete mixtures designed ranged from a 25% replacement to one 100% replacement with recycled materials. In addition, a standard concrete mixture using cement and virgin aggregates was designed for comparison purposes. Fresh and hardened concrete properties were examined including slump, air content, unit weight, compressive strength, rate of strength gain, freeze-thaw durability, permeability, and alkali-silica reactivity (ASR) potential. The 100% recycled materials concrete had very low permeability and a compressive strength of 4200 psi (29.0 MPa) with 6.5% air content. Concrete mixtures composed of 50% and 75% recycled materials achieved strengths of nearly 7000 psi (48 MPa) and 6350 psi (43.8 MPa) respectively. Beneficial and negative effects of using recycled materials in concrete mixtures were investigated, including the potential alkali-silica reactivity (ASR) of using waste glass as aggregate. The slag cement, when used at replacement levels of 50%, was found to eliminate these concerns. The use of recycled materials was beneficial with regards to strength and durability up to 50% when compared with a normal concrete made from virgin materials. © 2011 Elsevier Ltd. All rights reserved. Source

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