CHANNEL CHANGES DOWNSTREAM FROM A DAM1

ABSTRACT: A flood-control dam was completed during 1979 on Bear Creek, a small tributary stream to the South Platte River in the Denver, Colorado, area. Before and after dam closure, repetitive surveys between 1977 and 1992 at five cross sections downstream of the dam documented changes in channel morphology. During this 15-year period, channel width increased slightly, but channel depth increased by more than 40 percent. Within the study reach, stream gradient decreased and median bed material sizes coarsened from sand in the pools and fine gravel on the rime to a median coarse gravel throughout the reach. The most striking visual change was from a sparse growth of streamside grasses to a dense growth of riparian woody vegetation.     

Lessons learned from classroom training on natural attenuation of chlorinated solvents

Technology and information transfer are critical functions within the remediation industry. Researchers in the private sector, academia, and government all struggle to have their findings accepted and put to good use by the remediation industry at large but must work even harder to have their findings accepted and put into practice by state and federal regulators in the environmental agencies overseeing cleanups. Unfortunately, many technology and information transfer efforts fail to reach state and federal regulators, and even fewer achieve regulatory acceptance. A two‐year‐long campaign to deliver a training class on the natural attenuation of chlorinated solvents in groundwater is one prominent example of very effective technology and information transfer. Several of the elements and aspects of that successful training class are presented and discussed in order to provide others with a proven and workable template. © 2010 Wiley Periodicals, Inc.     

Improving Objectives for Cleanup Sites

In 1976, the discovery of the Love Canal Superfund Site in New York thrust environmental cleanups into the forefront of the national conscience and essentially launched the remediation industry. Since then, vast efforts have been devoted to improving site remediation. Despite the attention given to key subject areas, such as site characterization, risk assessment, and remediation technologies, relatively little attention has been given to the objectives set forth for conducting cleanups, and they have generally not been rigorously evaluated in the literature. Several of the more common objectives for remediation projects are discussed. © 2014 Wiley Periodicals, Inc.     

A simple model which predicts some non-linear features between atmospheric sulphur and sulphur emissions

This paper develops a simple model and suggests a plausible chemico-physical mechanism for a non-linear response between atmospheric sulphur and sulphur emissions. It contains simplified representations of transport, deposition and conversion processes and uses a proxy in-cloud oxidant-limited reaction along a pathway connecting an emission source with a receptor site. Individual pathway responses to emissions show linear behaviour above a threshold. However, by averaging the values of SO2 at the receptor site from different pathways a continuous non-linear relationship is obtained. As emissions reduce, distant emission sources become less significant contributors of sulphur dioxide at a receptor site but their emissions are still counted in an emission inventory, leading to an apparent non-linearity. Sulphate is always found to contribute a signal to the receptor site total. This model goes someway to explaining a proposed 'crossover' between observed proportions of wet and dry deposited sulphur in the UK as emissions have been reduced.     

Beyond Counting Climate Consensus

Several studies have been using quantified consensus within climate science as an argument to foster climate policy. Recent efforts to communicate such scientific consensus attained a high public profile but it is doubtful if they can be regarded successful. We argue that repeated efforts to shore up the scientific consensus on minimalist claims such as “humans cause global warming” are distractions from more urgent matters of knowledge, values, policy framing and public engagement. Such efforts to force policy progress through communicating scientific consensus misunderstand the relationship between scientific knowledge, publics and policymakers. More important is to focus on genuinely controversial issues within climate policy debates where expertise might play a facilitating role. Mobilizing expertise in policy debates calls for judgment, context and attention to diversity, rather than deferring to formal quantifications of narrowly scientific claims.     

Integrating Remediation and Reuse to Achieve Whole‐System Sustainability Benefits

This perspective article was prepared by members of the Sustainable Remediation Forum (SURF), a professional nonprofit organization seeking to advance the state of sustainable remediation within the broader context of sustainable site reuse. SURF recognizes that remediation and site reuse, including redevelopment activities, are intrinsically linked—even when remediation is subordinate to or sometimes a precursor of reuse. Although the end of the remediation life cycle has traditionally served as the beginning of the site's next life cycle, a disconnect between these two processes remains. SURF recommends a holistic approach that brings together remediation and reuse on a collaborative parallel path and seeks to achieve whole‐system sustainability benefits. This article explores the value of integrating remediation into the reuse process to fully exploit synergies and minimize the costs and environmental impacts associated with bringing land back into beneficial use. © 2013 Wiley Periodicals, Inc.