United States Bureau of Reclamation

About: United States Bureau of Reclamation is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Riparian zone & Drainage basin. The organization has 989 authors who have published 1250 publications receiving 25440 citations. The organization is also known as: United States Reclamation Service & Bureau of Reclamation.

Fine‐resolution climate projections enhance regional climate change impact studies

Abstract: A new data set enhances the abilities of researchers and decision-makers to assess possible future climates, explore societal impacts, and approach policy responses from a risk-based perspective. The data set, which consists of a library of 112 fine-resolution climate projections, based on 16 climate models and three greenhouse gas emissions scenarios, is now publicly available. Monthly climate projections from 1950 to 2099 were downscaled to a spatial resolution of ⅛° (about 140 square kilometers per grid cell) covering the conterminous United States and portions of Canada and Mexico. For the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, climate modeling groups produced hundreds of simulations of past and future climates. The colocation of these simulations in a single archive (at the Program for Climate Model Diagnosis and Intercomparison at Lawrence Livermore National Laboratory (LLNL), established to facilitate assessment of general circulation models, or GCMs) and the conversion of all results to a common data format have made probabilistic, multi-model projections and impact assessments practical. A remaining issue is that the spatial scale of climate model output is typically too coarse for regional impact studies. Multiple downscaling approaches exist for deriving regional climate from coarse-resolution model output; these approaches are typically applied on an ad hoc basis to a particular region.

Multidimensional evaluation of managed relocation.

Abstract: Managed relocation (MR) has rapidly emerged as a potential intervention strategy in the toolbox of biodiversity management under climate change. Previous authors have suggested that MR (also referred to as assisted colonization, assisted migration, or assisted translocation) could be a last-alternative option after interrogating a linear decision tree. We argue that numerous interacting and value-laden considerations demand a more inclusive strategy for evaluating MR. The pace of modern climate change demands decision making with imperfect information, and tools that elucidate this uncertainty and integrate scientific information and social values are urgently needed. We present a heuristic tool that incorporates both ecological and social criteria in a multidimensional decision-making framework. For visualization purposes, we collapse these criteria into 4 classes that can be depicted in graphical 2-D space. This framework offers a pragmatic approach for summarizing key dimensions of MR: capturing uncertainty in the evaluation criteria, creating transparency in the evaluation process, and recognizing the inherent tradeoffs that different stakeholders bring to evaluation of MR and its alternatives.

Electric Power from Differences in Salinity: The Dialytic Battery

Abstract: An array of alternating anion and cation exchange membranes can be used to generate electric power from the free energy of mixing of river and sea waters. A simple mathematical model, which predicts experimental results well, is useful in exploring conditions for optimization of the process. Major, but not impossible, improvements in technology would be required to bring the cost of power from the dialytic battery into line with foreseeable energy prices.

Stress-associated impacts of short-term holding on fishes

Abstract: Most sources of stress in aquaculture, fish salvage, stocking programs, and commercial and sport fisheries may be unavoidable. Collecting, handling, sorting, holding, and transporting are routine practices that can have significant effects on fish physiology and survival. Nevertheless, an understanding of the stressors affecting fish holding can lead to practices that reduce stress and its detrimental effects. The stress-related effects of short-term holding are influenced by water quality, confinement density, holding container design, and agonistic and predation-associated behaviors. Physiological demands (e.g., resulting from confinement-related stresses) exceeding a threshold level where the fish can no longer compensate may lead to debilitating effects. These effects can be manifested as suppressed immune systems; decreased growth, swimming performance, or reproductive capacity; even death. Furthermore, holding tolerance may depend upon the species, life stage, previous exposure to stress, and behavior of the held fish. Water quality is one of the most important contributors to fish health and stress level. Fish may be able to tolerate adverse water quality conditions; however, when combined with other stressors, fish may be quickly overcome by the resulting physiological challenges. Temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, pH, carbon dioxide, alkalinity, and hardness are the most common water quality parameters affecting physiological stress. Secondly, high fish densities in holding containers are the most common problem throughout aquaculture facilities, live-fish transfers, and fish salvage operations. Furthermore, the holding container design may also compromise the survival and immune function by affecting water quality, density and confinement, and aggressive interactions. Lastly, fishes held for relatively short durations are also influenced by negative interactions, associated with intraspecific and interspecific competition, cannibalism, predation, and determining nascent hierarchies. These interactions can be lethal (i.e., predation) or may act as a vector for pathogens to enter (i.e., bites and wounds). Predation may be a significant source of mortality for fisheries practices that do not sort by size or species while holding. Stress associated with short-term holding of fishes can have negative effects on overall health and well-being. These four aspects are major factors contributing to the physiology, behavior, and survival of fishes held for a relatively short time period.

The wetland continuum: a conceptual framework for interpreting biological studies

Abstract: We describe a conceptual model, the wetland continuum, which allows wetland managers, scientists, and ecologists to consider simultaneously the influence of climate and hydrologic setting on wetland biological communities. Although multidimensional, the wetland continuum is most easily represented as a two-dimensional gradient, with ground water and atmospheric water constituting the horizontal and vertical axes, respectively. By locating the position of a wetland on both axes of the continuum, the potential biological expression of the wetland can be predicted at any point in time. The model provides a framework useful in the organization and interpretation of biological data from wetlands by incorporating the dynamic changes these systems undergo as a result of normal climatic variation rather than placing them into static categories common to many wetland classification systems. While we developed this model from the literature available for depressional wetlands in the prairie pothole region of North America, we believe the concept has application to wetlands in many other geographic locations.