59 research outputs found

    Evaluating Effectiveness of Floodplain Sites along the Lamoille Valley Rail Trail: A Blueprint for Future Rail-River Projects

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    Floodplains perform many functions of value to society, including conveyance and storage of floodwaters for reduced downstream impacts, sediment and nutrient deposition to support soil formation, and maintenance of pulsed overbank flows to support diverse habitats. When constructed along Vermont’s river valleys in the mid-to-late 1800s, railroads often isolated large areas of natural floodplain, leading to decreased flood and sediment storage, and increased downstream flood stages, sediment and nutrient delivery. Where rail lines have been federally-banked and converted to recreational trails, floodplain reconnection could be achieved by modifying the rail embankment through lowering or installing cross culverts or bridges. With the Lamoille Valley Rail Trail (LVRT) in the Lamoille and Missisquoi River basins as a focal study area, this research has generated tools and planning frameworks for transportation and river managers to identify and prioritize candidate reconnection sites, and to holistically evaluate the benefits of these projects alongside potential impacts to adjacent infrastructure or land uses. Effectiveness of completed and proposed floodplain reconnection sites along the LVRT was evaluated at various spatial scales using a suite of tools. At the watershed and reach scales, a screening protocol was developed, leveraging stream geomorphic assessment data to prioritize potential floodplain reconnection sites for further vetting through field inspection. Ten out of twelve floodplain reconnection sites completed along the LVRT in 2006-2008 were predicted as a priority in a retrospective application of this screening protocol. Low-complexity (Height Above Nearest Drainage) hydraulic modeling results confirmed that most completed projects provided significant increases in the floodplain capacity for floods of 2- to 500-year recurrence intervals. Event-scale monitoring conducted at selected sites has confirmed accumulation of fine sediment and phosphorus. A conservative estimate of a half-ton of phosphorus deposited during one storm on 57 acres highlights the water quality benefits of restoring floodplains. Reconnection alternatives were evaluated in more detail using two-dimensional hydraulic modeling (2D HEC-RAS) at a demonstration reach of the Black Creek near East Fairfield spanning two completed reconnection sites and one proposed site on the LVRT. Modeled reconnection alternatives resulted in modest changes in flooding parameters due to an unexpected, existing degree of cross connection between floodplains of the Black Creek and Elm Brook tributary. Nevertheless, this research project has created a framework for more holistic analysis of floodplain reconnection opportunities at similar sites across Vermont and beyond. The hydraulic modeling products and scenarios developed for this project are being adapted to support analysis and modeling of fine sediment and phosphorus attenuation as the Vermont Agency of Transportation continues to collaborate with the Vermont Agency of Natural Resources and other stakeholders to develop a phosphorus-crediting framework for floodplain reconnection projects

    Engagement in water governance action situations in the Lake Champlain Basin

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    Water quality governance encompasses multiple “wicked” interacting problems that manifest within social-ecological systems. Concerned governments, institutions, and actors concerned with addressing these issues must wrestle with complex systems that span time, space, and scale. This complexity of connected systems requires the participation of multiple actors across political boundaries, problem areas, and hydrologic domains. In Lake Champlain (US), frequent cyanobacteria blooms negatively affect property values, recreational activities, and public infrastructure, in addition to their impacts on the aquatic ecosystem. Through a survey of actors working on water quality in the Lake Champlain Basin, we analyze how actor participation in structured issue forums creates a network of connected action situations across multiple spatial scales and problem domains. We apply exponential random graph models to quantify the effects of scale, issues, and homophily on actor participation in these forums. Our findings show that actors tend to favor participating in similarly scoped forums at their spatial scale, that actors are less likely to participate in structured forums focused on agriculture, and that actors participate independently of others with whom they have pre-existing collaborative relationships. Further, we find that in the case of the Lake Champlain Basin, actor participation in issues related to water quality is misaligned with modeled sources of nutrient pollution. This study demonstrates that the design and maintenance of water quality action situations play an important role in attracting the participation of actors working collaboratively to address wicked social-ecological problems. Further, linking current and potential configurations of governance networks to social-ecological outcomes can aid in the effective and efficient achievement of management objectives

    Strategies for assessing the implications of malformed frogs for environmental health

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    The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of faces and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment

    Building bridges, fording streams, reaching agreement in the Lake Champlain basin: Alternatives to legislation and regulation rooted in citizen and science-based approaches to inspire watershed protection

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    Challenges and opportunities arise when jointly managing international waters shared by two countries and two states with different political and governmental systems. Lake Champlain’s vast watershed is shared by the states of Vermont and New York in the United States of America and the Province of Québec in Canada. Transboundary relations are characterised by consensus reached through a continuous sequence of non-binding, non-regulatory environmental agreements. Since the historic 1988 Memorandum of Understanding on Environmental Cooperation on the Management of Lake Champlain, 16 additional agreements have been signed – averaging nearly one per year. They range from joint declarations and watershed plans to phosphorus standards and toxic spill responses. They are renewable agreements bearing the support and participation of state, provincial and federal agencies; local government; and businesses with a very strong citizen component. This progression of cooperative agreements falls under the auspices of the Lake Champlain Basin Program, a quasi-governmental partnership among Vermont, New York and Québec that coordinates Lake Champlain’s long-term management plan, Opportunities for Action: An Evolving Plan for the Future of the Lake Champlain Basin. The Lake Champlain Basin Program achieves significant watershed improvements through its consensus-based, decision-making policies bolstered by state-to-state, state-to-province agreements. This incremental approach, steeped in multi-level partnerships and institutions, epitomises the theory of natural resource regimes which emphasise roles of intermediate institutions in environmental management. Use of non-binding, renewable agreements more easily bridges differences among jurisdictions, whether interstate, intrastate or international. Additionally, such agreements can be updated more immediately as new information and technologies emerge. Voluntary, renewable agreements can be assembled more quickly than pursuing a traditional regulatory or legislative response. It is precisely the voluntary nature of these agreements and their successes that has captured the attention of other basins worldwide as a model for replication and reaching agreement on difficult issues.Keywords: transboundary, decision-making, watershed planning, integrated water resources management (IWRM), Lake Champlain, consensus, collaboration, stakeholder participation, stakeholder involvement, lake managemen

    Effective engagement of stakeholders in Total Maximum Daily Load development and implementation

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    Improving Detection And Prediction Of Bridge Scour Damage And Vulnerability Under Extreme Flood Events Using Geomorphic And Watershed Data

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    Bridge scour is the leading cause of bridge damage nationwide. Successfully mitigating bridge scour problems depends on our ability to reliably estimate scour potential, design safe and economical foundation elements that account for scour potential, identify vulnerabilities related to extreme events, and recognize changes to the environmental setting that increase risk at existing bridges. This study leverages available information, gathered from several statewide resources, and adds watershed metrics to create a comprehensive, georeferenced dataset to identify parameters that correlate to bridges damaged in an extreme flood event. Understanding the underlying relationships between existing bridge condition, fluvial stresses, and geomorphological changes is key to identifying vulnerabilities in both existing and future bridge infrastructure. In creating this comprehensive database of bridge inspection records and associated damage characterization, features were identified that correlate to and discriminate between levels of bridge damage. Stream geomorphic assessment features were spatially joined to every bridge, marking the first time that geomorphic assessments have been broadly used for estimating bridge vulnerability. Stream power assessments and watershed delineations for every bridge and stream reach were generated to supplement the comprehensive database. Individual features were tested for their significance to discriminate bridge damage, and then used to create empirical fragility curves and probabilistic predictions maps to aid in future bridge vulnerability detection. Damage to over 300 Vermont bridges from a single extreme flood event, the August 28, 2011 Tropical Storm Irene, was used as the basis for this study. Damage to historic bridges was also summarized and tabulated. In some areas of Vermont, the storm rainfall recurrence interval exceeded 500 years, causing widespread flooding and damaging over 300 bridges. With a dataset of over 330 features for more than 2,000 observations to bridges that were damaged as well as not damaged in the storm, an advanced evolutionary algorithm performed multivariate feature selection to overcome the shortfalls of traditional logistic regression analysis. The analysis identified distinct combinations of variables that correlate to the observed bridge damage under extreme food events

    Strategies for assessing the implications of malformed frogs for environmental health.

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    The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of fates and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment

    Assessing Uncertainty Associated with Groundwater and Watershed Problems Using Fuzzy Mathematics and Generalized Regression Neural Networks

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    When trying to represent an environmental process using mathematical models, uncertainty is an integral part of numerical representation. Physically-based parameters are required by such models in order to forecast or make predictions. Typically, when the uncertainty inherent in models is addressed, only aleatory uncertainty (irreducible uncertainty) is considered. This type of uncertainty is amenable to analysis using probability theory. However, uncertainty due to lack of knowledge about the system, or epistemic uncertainty, should also be considered. Fuzzy set theory and fuzzy measure theory are tools that can be used to better assess epistemic, as well as aleatory, uncertainty in the mathematical representation of the environment. In this work, four applications of fuzzy mathematics and generalized regression neural networks (GRNN) are presented. In the first, Dempster-Shafer theory (DST) is used to account for uncertainty that surrounds permeability measurements and is typically lost in data analysis. The theory is used to combine multiple sources of subjective information from two expert hydrologists and is applied to three different data collection techniques: drill-stem, core, and pump-test analysis. In the second, a modification is made to the fuzzy least-squares regression model and is used to account for uncertainty involved in using the Cooper-Jacob method to determine transmissivity and the storage coefficient. A third application, involves the development of a GRNN to allow for the use of fuzzy numbers. A small example using stream geomorphic condition assessments conducted in the state of Vermont is provided. Ultimately, this fuzzy GRNN will be used to better understand the relationship between the geomorphic and habitat conditions of stream reaches and their corresponding biological health. Finally, an application of the GRNN algorithm to explore links between physical stream geomorphic and habitat conditions and biological health of stream reaches is provided. The GRNN proves useful; however, physical and biological data collected concurrently is needed to enhance accuracy

    Modeling Alternative Collaborative Governance Network Designs: An Agent-Based Model of Water Governance in the Lake Champlain Basin, Vermont

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    Published by Oxford University Press on behalf of the Public Management Research Association. With the widespread use of collaborative governance mechanisms for mitigating water pollution, an opportunity exists to test alternative institutional designs based on collaborative governance theory using computer simulation models, particularly when there is a clear relationship between governance networks, observable resource allocation decisions, and measurable outcomes. This is especially the case for wicked problems like nonpoint source water pollution where there are compelling questions regarding how best to design policies, allocate funds, and build administrative capacity to meet water quality standards. We present an agent-based model (ABM) of water governance for the Lake Champlain Basin to simulate the impacts of alternative collaborative governance arrangements on the development of suites of water quality projects. The ABM is connected or coupled with land use and phosphorus load accumulation models that are informed by existing hydrologic models, project datasets, and state-set load reduction targets. We find that regionally arranged collaborative governance in water quality project planning and implementation can lead to better water quality outcomes, thereby affirming one of the central premises of collaborative governance regime theory. We also find that externally mandated collaboration, as opposed to voluntary, self-initiated collaboration, can lead to better water quality outcomes, adding to our understanding of which type of collaborative governance arrangement is best suited to the specific contexts of this case. Further, without adequate administrative capacity in the form of human resources located in central network actors to manage project funds, administrative bottlenecks may form and money can go unspent. This research demonstrates the efficacy of using simulations of alternative institutional design for theory testing and tuning, and policy prototyping

    A review of river habitat characterisation methods: indices vs. characterisation protocols

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    RESUMEN. Una gran variedad de metodologías se han propuesto para la caracterización de los hábitats fluviales a fin de cumplir con diferentes objetivos medioambientales. Esta diversidad de métodos puede ser vista como una ventaja para hacer frente a diferentes objetivos ambientales. Sin embargo, el seguimiento a medio o largo plazo de las características físicas del hábitat fluvial carece de una metodología estandarizada, lo cual contrasta con otros métodos mucho mejor establecidos para el seguimiento de otros componentes del ecosistema fluvial. Se han hecho algunos intentos para estandarizar los métodos de caracterización de los hábitats fluviales, y estos incluyen el estándar europeo para la evaluación de las características hidromorfológicas de los ríos (CEN, 2002), y el desarrollo del módulo de evaluación fisicoquímica dentro del sistema australiano de evaluación fluvial (AusRivAS). Uno de los primeros pasos para avanzar en el desarrollo y uso de métodos para la caracterización de los hábitats fluviales en los programas de seguimiento a medio y largo plazo es revisar las prácticas actuales a fin de poder abordar las deficiencias e introducir mejoras. En el presente trabajo se revisan más de 50 métodos que se han utilizado para caracterizar los hábitats fluviales en todo el mundo, utilizando el estándar europeo como referencia para comparar los métodos. Los métodos de caracterización de los hábitats fluviales se diferencian principalmente por tres razones: (1) los objetivos para los que fueron diseñados, (2) el tiempo que demanda su aplicación y (3) unos miden mientras otros evalúan las características del hábitat. Las características del cauce y de la zona ribereña son consideradas por un mayor número de métodos que las características de la llanura de inundación. Además, entre todas las características del hábitat fluvial descritas, la estabilidad de las orillas, el sustrato del lecho, las estructuras artificiales, la estructura de la vegetación ribereña, las dimensiones del cauce, el tipo de flujo o el caudal, los usos del suelo adyacentes y las barras de sedimentos son las más comúnmente registradas. Se concluye que los métodos de medición de las características del hábitat fluvial que recogen información cuantitativa cubriendo diferentes escalas espaciales podrían ser los más eficaces, ya que proporcionan bases de datos más amplias que permiten utilizar la información para diversos objetivos. Por último, algunos tipos de ríos, como los ríos intermitentes, requieren un mayor estudio para poder identificar correctamente los atributos físicos y la metodología adecuada para realizar el seguimiento de las características del hábitat.ABSTRACT. A wide variety of methodologies have been proposed for characterising river habitats in order to meet different environmental objectives. However, mid- to long-term monitoring of the physical characteristics of river habitats lacks a standardised methodology. This contrasts with well-established methods for monitoring other river ecosystem components. Some attempts have been made to standardise the methods for characterising river habitats including the European Guidance Standard for Assessing the Hydromorphological Characteristics of Rivers (CEN, 2002) and the Physical and Chemical AssessmentModule within the Australian River Assessment System (AusRivAS). One of the first steps toward advancing the development and use of methods for characterising river habitats in mid- to long-term monitoring programs is to review current practices so that deficiencies can be identified and addressed. In the present work, we review more than 50 methods that have been used to characterise river habitats worldwide. This review uses the European standard as a reference benchmark for comparison with existing methods of river habitat characterisation. Methods of characterising river habitats differ mainly with respect to three features: (1) the objectives for which they were designed, (2) the time required for their application and (3) whether they measure characteristics or evaluate them. Channel and riparian zone characteristics are more extensively covered than floodplain characteristics. Moreover, of all the described river habitat characteristics, bank stability, channel substrate, artificial structures, riparian vegetation structure, channel dimensions, flow types or flow status, adjacent land uses and bars are the most commonly recorded.We conclude that assessment methods of river habitat characteristics that gather quantitative information at a range of spatial scales could be the most effective, as they provide relatively extensive data sets that can be used to analyse information for several purposes. Finally, some types of rivers, such as intermittent rivers, require further work in order to identify their physical habitat characteristics and the proper monitoring methodology
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