12 research outputs found
Let\u27s Get It Write! Principles of Writing Construction Specifications and Special Provisions
The purpose of this presentation is to assist project managers and designers in preparing the necessary information required for Department contracts with regard to the Standard Specifications and Special Provisions. Attendees will be provided examples of both the right and wrong ways to present a Unique Special Provision, as well as things to avoid and questions to ask in order to adhere to legal, moral, and ethical construction standards
Principles of Writing Construction Specifications and Special Provisions
This presentation will help project managers and designers prepare the necessary information required for department and local public agency contracts with regard to the Standard Specifications and any necessary special provisions. Attendees will be provided examples of the proper way to present a Unique Special Provision, including things to avoid and questions to ask, in order to adhere to legal, moral, and ethical construction standards
Translocation of Humpback Chub into Tributary Streams of the Colorado River: Implications for Conservation of Large- River Fishes
The Humpback Chub Gila cypha, a large-bodied, endangered cyprinid endemic to the Colorado River basin, is in decline throughout most of its range due largely to anthropogenic factors. Translocation of Humpback Chub into tributaries of the Colorado River is one conservation activity that may contribute to the expansion of the species’ current range and eventually provide population redundancy. We evaluated growth, survival, and dispersal following translocation of approximately 900 Humpback Chub over a period of 3 years (2009, 2010, and 2011) into Shinumo Creek, a tributary stream of the Colorado River within Grand Canyon National Park. Growth and condition of Humpback Chub in Shinumo Creek were consistent among year-classes and equaled or surpassed growth estimates from both the main-stem Colorado River and the Little Colorado River, where the largest (and most stable) Humpback Chub aggregation remains. Based on passive integrated tag recoveries, 53% ( D 483/902) of translocated Humpback Chub dispersed from Shinumo Creek into the main-stem Colorado River as of January 2013, 35% leaving within 25 d following translocation. Annual apparent survival estimates within Shinumo Creek ranged from 0.22 to 0.41, but were strongly influenced by emigration. Results indicate that Shinumo Creek provides favorable conditions for growth and survival of translocated Humpback Chub and could support a new population if reproduction and recruitment occur in the future. Adaptation of translocation strategies of Humpback Chub into tributary streams ultimately may refine the role translocation plays in recovery of the species
Construction Specifications and Special Provisions
The purpose of this presentation is to help project managers and designers prepare the necessary information required for their contracts with regard to the Standard Specifications and any necessary special provisions. Attendees will be exposed to examples of the right way to incorporate a Unique Special Provision, as well as things to avoid and questions to ask. It is important to know the proper way to write and present a Unique Special Provision
Construction Specifications 101
This presentation will help project managers and designers prepare the necessary information required for their contracts with regard to the standard specifications and any necessary special provisions. If the desired information is not readily found in the standard specifications or in the list of recurring special provisions, it may be necessary to incorporate a unique special provision (USP). It is important to know the proper way to write and present a USP
Translocation of Humpback Chub into Tributary Streams of the Colorado River: Implications for Conservation of Large- River Fishes
The Humpback Chub Gila cypha, a large-bodied, endangered cyprinid endemic to the Colorado River basin, is in decline throughout most of its range due largely to anthropogenic factors. Translocation of Humpback Chub into tributaries of the Colorado River is one conservation activity that may contribute to the expansion of the species’ current range and eventually provide population redundancy. We evaluated growth, survival, and dispersal following translocation of approximately 900 Humpback Chub over a period of 3 years (2009, 2010, and 2011) into Shinumo Creek, a tributary stream of the Colorado River within Grand Canyon National Park. Growth and condition of Humpback Chub in Shinumo Creek were consistent among year-classes and equaled or surpassed growth estimates from both the main-stem Colorado River and the Little Colorado River, where the largest (and most stable) Humpback Chub aggregation remains. Based on passive integrated tag recoveries, 53% ( D 483/902) of translocated Humpback Chub dispersed from Shinumo Creek into the main-stem Colorado River as of January 2013, 35% leaving within 25 d following translocation. Annual apparent survival estimates within Shinumo Creek ranged from 0.22 to 0.41, but were strongly influenced by emigration. Results indicate that Shinumo Creek provides favorable conditions for growth and survival of translocated Humpback Chub and could support a new population if reproduction and recruitment occur in the future. Adaptation of translocation strategies of Humpback Chub into tributary streams ultimately may refine the role translocation plays in recovery of the species
Ecological Risk Assessment of Managed Relocation as a Climate Change Adaptation Strategy
Executive Summary
Changing climate and introduced species are placing an increasing number of species at risk of extinction. Increasing extinction risk is increasing calls to protect species by relocating, or translocating, them to locations with more favorable biotic or climatic conditions. Managed relocation, or assisted migration, of species entails risks to both the conservation target organisms being moved as well as the recipient ecosystems into which they are moved.
Recognizing this risk, calls have been made for practitioners interested in considering a managed relocation project to engage in a serious risk assessment prior to advancing a project. We engaged a team of researchers and resource managers to create risk assessment protocols that could be used by natural resource managers within U.S. National Parks, or elsewhere, to help inform a decision of whether the risks involved in managed relocation are warranted. These protocols facilitate evaluation of the ecological risk of species managed relocation as part of planning and decision making. This is not a policy document. It neither introduces new policy, nor serves to interpret or resolve current policies regarding managed relocation (or assisted migration) as a natural resource management strategy.
We assembled a team of five university researchers and ten federal resource management researchers and staff to develop a practical management-oriented risk assessment strategy. We jointly agreed to a set of principles to guide this managed relocation risk assessment strategy. This protocol and accompanying spreadsheet would be used to help a decision-maker structure a decision process but would not strive to provide a formulaic decision output. Identifying, evaluating, and managing risk is a subjective decision that is the responsibility of the decision authority.
We began by defining the scope of this work to include moving populations or species for the purpose of conserving the target populations or species that are threatened by climate or invasive species. We also included species movements for the purpose of retaining some critical ecosystem function. We did not include management actions such as planned ecosystem re-alignment for climate change or other kinds of translocations associated with ecosystem manipulation (e.g., habitat restoration), although these protocols may be useful for some of those management actions with minor modification.
We adopted the premise that risk decisions are inherently subjective and that different aspects of risk (e.g. the risk of a moved species introducing a novel pathogen to an ecosystem, the risk of unwanted evolution in the moved species) are non-additive. Hence, our strategy is designed to encourage managers to think broadly and comprehensively about risk in order to make the best possible decision given alternate opposing risks (i.e. the risk of extinction versus the risk of causing unintended harm to other species and ecosystems in the process of trying to save a species).
We identified six major areas of risk, with a total of seventeen sub-categories. These are:
• Risks of no managed relocation action. Risk of:
o no action on the target
o no action on the recipient ecosystem
• Risks of managed relocation action to the target. Risks of:
o action on the translocated individuals
o target source population extirpation through diminished numbers
o reduced ecological functioning of the source ecosystem
o causing undesired evolution in the target
• Risks of action on non-targets in the recipient ecosystem. Risks of:
o target transmitting novel disease or associated pest
o negative competitive interactions on non-target populations
o predation, herbivory, or allelopathic effects on non-target populations o driving undesirable evolution in non-target species
• Risks of action on higher order attributes of the recipient ecosystem. Risks of:
o indirect and negative impacts on ecosystem structure
o changing ecosystem function
• Risks associated with invasion. Risks of:
o invasion within the intended recipient ecosystem
o invasion beyond recipient ecosystem
o irreversibility of the managed relocation action
• Risks associated with socio-economic values. Risks to:
o culturally or economically important species
o valued ecosystem services
For each risk category we provide guidance on risk scoring. Risk scoring is comprised of a risk rank category (low, moderate, high, very high) and a confidence score (low, medium, high). Confidence is a combined attribute of the strength of evidence and the agreement of that evidence.
The protocols are presented in an accompanying Excel spreadsheet that uses a graphical tool to allow users to visualize a composite of risk and confidence. We are adamant about not summing across risk categories. Instead, we provide a graphing tool that summarizes risk within categories. We suggest that users could find risks posed by a proposed action to be acceptable if:
1) Confidence scores are sufficient that managers feel confident that the risk assessment is informative;
2) There is no single risk category that is so high and so important as to make the project unacceptably risky; and
3) The general distribution of risk is not so high as to exceed some level of expectation that one of many potential problems could arise and lead to decision regret.
We frame this risk assessment within the context of other critical questions that need to be answered in order to proceed toward strategic planning for a managed relocation action. These include justifying ecological need, assessing technical feasibility, cost, management priority and social acceptability. If all these criteria are met, then these same protocols can be used in a multi-criteria assessment to compare across different strategic plans for managed relocation (e.g. relocation location, relocation numbers, source and husbandry of relocated individuals). We provide brief guidance on how that may be completed with no presumption of final decision determination.
Finally, in the process of developing these risk scoring protocols, we tested them on a suite of four case studies (bull trout, Karner blue butterfly, giant sequoia and Pitcher’s thistle). These are provided in this document as examples of the logic and process that we outline for assessing risk. These were, however, done without broad consultation and should be taken not as definitive risk assessments of managed relocation for these species, but as examples of how one might use our strategy for an assessment of ecological risk associated with managed relocation
Draining the Landscape: How Do Nitrogen Concentrations in Riparian Groundwater and Stream Water Change Following Milldam Removal?
Dam removals are on the increase across the US with Pennsylvania currently leading the nation. While most dam removals are driven by aquatic habitat and public safety considerations, we know little about how dam removals impact water quality and riparian zone processes. Dam removals decrease the stream base level, which results in dewatering of the riparian zone. We hypothesized that this dewatering of the riparian zone would increase nitrification and decrease denitrification, and thus result in nitrogen (N) leakage from riparian zones. This hypothesis was tested for a 1.5 m high milldam removal. Stream, soil water, and groundwater N concentrations were monitored over 2 years. Soil N concentrations and process rates and δ15N values were also determined. Denitrification rates and soil δ15N values in riparian sediments decreased supporting our hypothesis but no significant changes in nitrification were observed. While surficial soil water nitrate-N concentrations were high (median 4.5 mg N L−1), riparian groundwater nitrate-N values were low (median 0.09 mg N L−1), indicating that nitrate-N leakage was minimal. We attribute the low groundwater nitrate-N to denitrification losses at the lower, more dynamic, groundwater interface and/or dissimilatory nitrate reduction to ammonium (DNRA). Stream water nitrate-N concentrations were high (median 7.6 mg N L−1) and contrary to our dam-removal hypothesis displayed a watershed-wide decline that was attributed to regional hydrologic changes. This study provided important first insights on how dam removals could affect N cycle processes in riparian zones and its implications for water quality and watershed management
Saturated, Suffocated, and Salty: Human Legacies Produce Hot Spots of Nitrogen in Riparian Zones
The compounding effects of anthropogenic legacies for environmental pollution are significant, but not well understood. Here, we show that centennial-scale legacies of milldams and decadal-scale legacies of road salt salinization interact in unexpected ways to produce hot spots of nitrogen (N) in riparian zones. Riparian groundwater and stream water concentrations upstream of two mid-Atlantic (Pennsylvania and Delaware) milldams, 2.4 and 4 m tall, were sampled over a 2 year period. Clay and silt-rich legacy sediments with low hydraulic conductivity, stagnant and poorly mixed hydrologic conditions, and persistent hypoxia in riparian sediments upstream of milldams produced a unique biogeochemical gradient with nitrate removal via denitrification at the upland riparian edge and ammonium-N accumulation in near-stream sediments and groundwaters. Riparian groundwater ammonium-N concentrations upstream of the milldams ranged from 0.006 to 30.6 mgN L−1 while soil-bound values were 0.11–456 mg kg−1. We attribute the elevated ammonium concentrations to ammonification with suppression of nitrification and/or dissimilatory nitrate reduction to ammonium (DNRA). Sodium inputs to riparian groundwater (25–1,504 mg L−1) from road salts may further enhance DNRA and ammonium production and displace sorbed soil ammonium-N into groundwaters. This study suggests that legacies of milldams and road salts may undercut the N buffering capacity of riparian zones and need to be considered in riparian buffer assessments, watershed management plans, and dam removal decisions. Given the widespread existence of dams and other barriers and the ubiquitous use of road salt, the potential for this synergistic N pollution is significant