My research interests include evaluating the relationship between hydrology-mediated disturbances to aquatic communities, especially fish communities, and broader ecosystem services. My research has ranged from theoretical, such as evaluating fish and macroinvertebrate nutrient cycling in streams, to very applied, such as evaluating different types of sampling methods on fish species detection. Other research interests have included studying basic fish life history requirements, fish spawning habitat and behavior, and the relative importance of riverscape features in structuring fish assemblages. Of particular interest, is researching how dams alter stream hydrology and geomorphology and induce responses in fish and riparian communities. In general, I attempt to find effective approaches to management including developing frameworks to organize restoration strategies or finding creative solutions to incorporate research in policy, specifically environmental flows. Phone: 865-241-8668 Address: Oak Ridge National Laboratory
Environmental Sciences Division
Bldg 1505, Office 338
Oak Ridge, TN 37831-6038
Understanding resource demands and tradeoffs among energy, water, and land socioeconomic sectors ... more Understanding resource demands and tradeoffs among energy, water, and land socioeconomic sectors requires an explicit consideration of spatial scale. However, incorporation of land dynamics within the energy-water nexus has been limited due inconsistent spatial units of observation from disparate data sources. Herein we describe the development of a National Water and Energy Land Dataset (NWELD) for the conterminous United States. NWELD is a 30-m, 86-layer rasterized dataset depicting the land use of mappable components of the United States energy sector life cycles (and related water used for energy), specifically the extraction, development, production, storage, distribution, and operation of eight renewable and non-renewable technologies. Through geospatial processing and programming, the final products were assembled using four different methodologies, each depending upon the nature and availability of raw data sources. For validation, NWELD provided a relatively accurate portra...
Stream classifications are important for understanding stream ecosystem diversity while also serv... more Stream classifications are important for understanding stream ecosystem diversity while also serving as tools for aquatic conservation and management. With current rates of land and riverscape modification within the United States (US), a comprehensive inventory and evaluation of naturally occurring stream habitats is needed, as this provides a physical template upon which stream biodiversity is organized and maintained. To adequately represent the heterogeneity of stream ecosystems, such a classification needs to be spatially extensive where multiple stream habitat components are represented at the highest resolution possible. Herein, we present a multi-layered empirically-driven stream classification system for the conterminous US, constructed from over 2.6 million stream reaches within the NHDPlus V2 stream network. The classification is based on emergent natural variation in six habitat layers meaningful at the stream-reach resolution: size, gradient, hydrology, temperature, net...
Describing the physical habitat diversity of stream types is important for understanding stream e... more Describing the physical habitat diversity of stream types is important for understanding stream ecosystem complexity, but also prioritizing management of stream ecosystems, especially those that are rare. We developed a stream classification system of six physical habitat layers (size, gradient, hydrology, temperature, valley confinement, and substrate) for approximately 1 million stream reaches within the Eastern United States in order to conduct an inventory of different types of streams and examine stream diversity. Additionally, we compare stream diversity to patterns of anthropogenic disturbances to evaluate associations between stream types and human disturbances, but also to prioritize rare stream types that may lack natural representation in the landscape. Based on combinations of different layers, we estimate there are anywhere from 1,521 to 5,577 different physical types of stream reaches within the Eastern US. By accounting for uncertainty in class membership, these estim...
The global recognition of the importance of natural flow regimes to sustain the ecological integr... more The global recognition of the importance of natural flow regimes to sustain the ecological integrity of river systems has led to increased societal pressure on the hydropower industry to change plant operations to improve downstream aquatic ecosystems. However, a complete reinstatement of natural flow regimes is often unrealistic when balancing water needs for ecosystems, energy production, and other human uses. Thus, stakeholders must identify a prioritized subset of flow prescriptions that meet ecological objectives in light of realistic constraints. Yet, isolating aspects of flow regimes to restore downstream of hydropower facilities is among the greatest challenges of environmental flow science due, in part, to the sheer volume of available environmental flow tools in conjunction with complex negotiation-based regulatory procedures. Herein, we propose an organizational framework that structures information and existing flow paradigms into a staged process that assists stakeholders in implementing environmental flows for hydropower facilities. The framework identifies areas where regulations fall short of the needed scientific process, and provide suggestions for stakeholders to ameliorate those situations through advanced preparation. We highlight the strengths of existing flow paradigms in their application to hydropower settings and suggest when and where tools are most applicable. Our suggested framework increases the effectiveness and efficiency of the e-flow implementation process by rapidly establishing a knowledge base and decreasing uncertainty so more time can be devoted to filling knowledge gaps. Lastly, the framework provides the structure for a coordinated research agenda to further the science of environmental flows related to hydropower environments.
Canadian Journal of Fisheries and Aquatic Sciences, 2015
Unregulated river systems are organized in a hierarchy in which large-scale factors (i.e., landsc... more Unregulated river systems are organized in a hierarchy in which large-scale factors (i.e., landscape and segment scales) influence local habitats (i.e., reach, meso-, and microhabitat scales), and both differentially exert selective pressures on biota. Dams, however, create discontinua in these processes and change the hierarchical structure. We examined the relative roles of hydrology and other instream factors, within a hierarchical landscape context, in organizing fish communities in regulated and unregulated tributaries to the Upper Tennessee River, USA. We used multivariate regression trees to identify factors that partition fish assemblages based on trait similarities, irrespective of spatial scale. We then used classical path analysis and structural equation modeling to evaluate the most plausible hierarchical causal structure of specific trait-based community components, given the data. Both statistical approaches suggested that river regulation affects stream fishes through...
Understanding resource demands and tradeoffs among energy, water, and land socioeconomic sectors ... more Understanding resource demands and tradeoffs among energy, water, and land socioeconomic sectors requires an explicit consideration of spatial scale. However, incorporation of land dynamics within the energy-water nexus has been limited due inconsistent spatial units of observation from disparate data sources. Herein we describe the development of a National Water and Energy Land Dataset (NWELD) for the conterminous United States. NWELD is a 30-m, 86-layer rasterized dataset depicting the land use of mappable components of the United States energy sector life cycles (and related water used for energy), specifically the extraction, development, production, storage, distribution, and operation of eight renewable and non-renewable technologies. Through geospatial processing and programming, the final products were assembled using four different methodologies, each depending upon the nature and availability of raw data sources. For validation, NWELD provided a relatively accurate portra...
Stream classifications are important for understanding stream ecosystem diversity while also serv... more Stream classifications are important for understanding stream ecosystem diversity while also serving as tools for aquatic conservation and management. With current rates of land and riverscape modification within the United States (US), a comprehensive inventory and evaluation of naturally occurring stream habitats is needed, as this provides a physical template upon which stream biodiversity is organized and maintained. To adequately represent the heterogeneity of stream ecosystems, such a classification needs to be spatially extensive where multiple stream habitat components are represented at the highest resolution possible. Herein, we present a multi-layered empirically-driven stream classification system for the conterminous US, constructed from over 2.6 million stream reaches within the NHDPlus V2 stream network. The classification is based on emergent natural variation in six habitat layers meaningful at the stream-reach resolution: size, gradient, hydrology, temperature, net...
Describing the physical habitat diversity of stream types is important for understanding stream e... more Describing the physical habitat diversity of stream types is important for understanding stream ecosystem complexity, but also prioritizing management of stream ecosystems, especially those that are rare. We developed a stream classification system of six physical habitat layers (size, gradient, hydrology, temperature, valley confinement, and substrate) for approximately 1 million stream reaches within the Eastern United States in order to conduct an inventory of different types of streams and examine stream diversity. Additionally, we compare stream diversity to patterns of anthropogenic disturbances to evaluate associations between stream types and human disturbances, but also to prioritize rare stream types that may lack natural representation in the landscape. Based on combinations of different layers, we estimate there are anywhere from 1,521 to 5,577 different physical types of stream reaches within the Eastern US. By accounting for uncertainty in class membership, these estim...
The global recognition of the importance of natural flow regimes to sustain the ecological integr... more The global recognition of the importance of natural flow regimes to sustain the ecological integrity of river systems has led to increased societal pressure on the hydropower industry to change plant operations to improve downstream aquatic ecosystems. However, a complete reinstatement of natural flow regimes is often unrealistic when balancing water needs for ecosystems, energy production, and other human uses. Thus, stakeholders must identify a prioritized subset of flow prescriptions that meet ecological objectives in light of realistic constraints. Yet, isolating aspects of flow regimes to restore downstream of hydropower facilities is among the greatest challenges of environmental flow science due, in part, to the sheer volume of available environmental flow tools in conjunction with complex negotiation-based regulatory procedures. Herein, we propose an organizational framework that structures information and existing flow paradigms into a staged process that assists stakeholders in implementing environmental flows for hydropower facilities. The framework identifies areas where regulations fall short of the needed scientific process, and provide suggestions for stakeholders to ameliorate those situations through advanced preparation. We highlight the strengths of existing flow paradigms in their application to hydropower settings and suggest when and where tools are most applicable. Our suggested framework increases the effectiveness and efficiency of the e-flow implementation process by rapidly establishing a knowledge base and decreasing uncertainty so more time can be devoted to filling knowledge gaps. Lastly, the framework provides the structure for a coordinated research agenda to further the science of environmental flows related to hydropower environments.
Canadian Journal of Fisheries and Aquatic Sciences, 2015
Unregulated river systems are organized in a hierarchy in which large-scale factors (i.e., landsc... more Unregulated river systems are organized in a hierarchy in which large-scale factors (i.e., landscape and segment scales) influence local habitats (i.e., reach, meso-, and microhabitat scales), and both differentially exert selective pressures on biota. Dams, however, create discontinua in these processes and change the hierarchical structure. We examined the relative roles of hydrology and other instream factors, within a hierarchical landscape context, in organizing fish communities in regulated and unregulated tributaries to the Upper Tennessee River, USA. We used multivariate regression trees to identify factors that partition fish assemblages based on trait similarities, irrespective of spatial scale. We then used classical path analysis and structural equation modeling to evaluate the most plausible hierarchical causal structure of specific trait-based community components, given the data. Both statistical approaches suggested that river regulation affects stream fishes through...
Human alteration of natural flow regimes has long been identified as a leading threat to surface ... more Human alteration of natural flow regimes has long been identified as a leading threat to surface water resources and aquatic ecosystems in the United States (USEPA, 1998). The most conspicuous and commonly studied sources of alteration are typically dams and water withdrawals associated with agricultural operations and industrial consumptive uses. The advent of horizontal hydraulic fracturing has led to a proliferation of natural gas drilling in the Marcellus Shale regions of West Virginia and Pennsylvania, with expansion likely in the neighboring states of Ohio, New York, Virginia and Maryland. The development of a typical gas well requires substantial amounts of water - often obtained via surface water withdrawal from nearby streams. Given the current extent of gas development and the fact that growing energy needs will continue to drive further development, hydraulic fracturing may pose an additional, potentially critical threat to aquatic biota in the region. Despite the serious implications of continued gas development, little guidance currently exists for water resource managers who are tasked with balancing human and ecosystem water demands. This project aims to establish ecologically-defined guidance on allowable water withdrawals for hydraulic fracturing through the application of the Ecological Limits of Hydrologic Alteration (ELOHA) approach. The project has been divided into two phases. Phase I reviews existing tools and approaches, as well as gathers and formats available and relevant data within the Marcellus Shale Region (MSR); Phase II applies the most appropriate tools to: i) build a hydrologic foundation, ii) estimate flow alteration, iii) develop flow-ecology relationships to provide guidance for establishing quantitative limits to water withdrawals associated with gas development and iv) conduct a pumping scenario analysis to assess the potential hydrologic effects of water withdrawals and to inform a water resource risk assessment in the MSR. This document summarizes progress made towards the completion of both phases.
The Basin Scale Opportunity Assessment (BSOA) initiative, led by the Department of Energy’s (DOE)... more The Basin Scale Opportunity Assessment (BSOA) initiative, led by the Department of Energy’s (DOE) Water Power Program, was designed to establish an integrative approach to assess the potential for combined increases in hydropower energy and improvements in the environment at a basin scale. Methods were developed to isolate mutual benefits to hydropower energy production and environmental protection. To date, the majority of environmental mitigation at hydropower facilities has occurred within the vicinity or project area of hydropower facilities (i.e., direct environmental opportunities). This report summarizes a methodology to identify environmental opportunities independent of a hydropower development and operations (i.e., indirect opportunities), i.e. those that occur outside the project area or not in close proximity to hydropower facilities that may complement increases in energy production. Indirect opportunities include acquisition of conservation land, wetland mitigation, riparian improvements, stream habitat restoration, and removal of non-powered dams. Using geospatial datasets summarizing landscape and stream conditions and the occurrence of high-profile aquatic and terrestrial species of concern, we created a framework to identify indirect opportunities and applied the methodology to the Roanoke Basin (North Carolina and Virginia, USA) as a case study. A scoring system was developed to prioritize indirect opportunities based on landscape/stream condition and the presence of species of concern. In addition, literature reviews and geospatial procedures were used to identify the social emphasis (overall prevalence and spatial variation in prevalence) of various direct and indirect environmental opportunities. The inclusion of indirect opportunities may provide greater potential for environmental mitigation and improvements related to a specific project or hydropower development because indirect environmental opportunities are pervasive and do not rely on direct geographic affiliation with a hydropower facility. The full potential of mutual benefits to hydropower energy production and environmental protection may be underestimated if based solely on potential opportunities near a facility. The methodology presented also has further reaching implications, such as providing environmental stakeholders with mechanisms to prioritize restoration actions within a basin, irrespective of hydropower.
Among the ecological science community, the consensus view is that the natural flow regime sustai... more Among the ecological science community, the consensus view is that the natural flow regime sustains the ecological integrity of river systems. This prevailing viewpoint by many environmental stakeholders has progressively led to increased pressure on hydropower dam owners to change plant operations to affect downstream river flows with the intention of providing better conditions for aquatic biological communities. Identifying the neccessary magnitude, frequency, duration, timing, or rate of change of stream flows to meet ecological needs in a hydropower context is challenging because the ecological responses to changes in flows may not be fully known, there are usually a multitude of competing users of flow, and implementing environmental flows usually comes at a price to energy production. Realistically, hydropower managers must develop a reduced set of goals that provide the most benefit to the identified ecological needs. As a part of the Department of Energy (DOE) Water Power Program, the Instream Flow Project (IFP) was carried out by Oak Ridge National Laboratory (ORNL), Pacific Northwest National Laboratory (PNNL), and Argon National Laboratory (ANL) as an attempt to develop tools aimed at defining environmental flow needs for hydropower operations. The application of these tools ranges from national to site-specific scales; thus, the utility of each tool will depend on various phases of the environmental flow process. Given the complexity and sheer volume of applications used to determine environmentally acceptable flows for hydropower, a framework is needed to organize efforts into a staged process dependent upon spatial, temporal, and functional attributes. By far, the predominant domain for determining environmental flows related to hydropower is within the Federal Energy Regulatory Commission (FERC) relicensing process. This process can take multiple years and can be very expensive depending on the scale of each hydropower project. The utility of such a framework is that it can expedite the environmental flow process by 1) organizing data and applications to identify predictable relationships between flows and ecology, and 2) suggesting when and where tools should be used in the environmental flow process. In addition to regulatory procedures, a framework should also provide the coordination for a comprehensive research agenda to guide the science of environmental flows. This research program has further reaching benefits than just environmental flow determination by providing modeling applications, data, and geospatial layers to inform potential hydropower development. We address several objectives within this document that highlight the limitations of existing environmental flow paradigms and their applications to hydropower while presenting a new framework catered towards hydropower needs. Herein, we address the following objectives: 1) Provide a brief overview of the Natural Flow Regime paradigm and existing environmental flow frameworks that have been used to determine ecologically sensitive stream flows for hydropower operations. 2) Describe a new conceptual framework to aid in determining flows needed to meet ecological objectives with regard to hydropower operations. The framework is centralized around determining predictable relationships between flow and ecological responses. 3) Provide evidence of how efforts from ORNL, PNNL, and ANL have filled some of the gaps in this broader framework, and suggest how the framework can be used to set the stage for a research agenda for environmental flow.
Spatially accurate geospatial information is required to support decision-making regarding sustai... more Spatially accurate geospatial information is required to support decision-making regarding sustainable future hydropower development. Under a memorandum of understanding among several federal agencies, a pilot study was conducted to map a subset of National Wild and Scenic Rivers (WSRs) at a higher resolution and provide a consistent methodology for mapping WSRs across the United States and across agency jurisdictions. A subset of rivers (segments falling under the jurisdiction of the National Park Service) were mapped at a high resolution using the National Hydrography Dataset (NHD). The spatial extent and representation of river segments mapped at NHD scale were compared with the prevailing geospatial coverage mapped at a coarser scale. Accurately digitized river segments were linked to environmental attribution datasets housed within the Oak Ridge National Laboratory’s National Hydropower Asset Assessment Program database to characterize the environmental context of WSR segments. The results suggest that both the spatial scale of hydrography datasets and the adherence to written policy descriptions are critical to accurately mapping WSRs. The environmental characterization provided information to deduce generalized trends in either the uniqueness or the commonness of environmental variables associated with WSRs. Although WSRs occur in a wide range of human-modified landscapes, environmental data layers suggest that they provide habitats important to terrestrial and aquatic organisms and recreation important to humans. Ultimately, the research findings herein suggest that there is a need for accurate, consistent, mapping of the National WSRs across the agencies responsible for administering each river. Geospatial applications examining potential landscape and energy development require accurate sources of information, such as data layers that portray realistic spatial representations.
The purpose of this project was to compile a body of knowledge on empirical and theoretical relat... more The purpose of this project was to compile a body of knowledge on empirical and theoretical relationships between flow and ecology in the South Atlantic region and support efforts to develop ecological limits of hydrologic alteration and environmental flow standards. Our goals were to 1) conduct a literature review, 2) develop a database of meta-data associated with each source of information, 3) summarize the key findings, and 4) conduct a qualitative and quantitative analysis of generalized relationships between altered flow and ecology. We gathered sources of information through database searches, internet searches, and contacting representative agency personnel within the South Atlantic region.
We found a total of 186 sources that provided a qualitative or quantitative relationship between flow and ecology within states encompassing the South Atlantic region. Of the sources, 128 were peer-reviewed published articles, 55 were grey literature, and 3 were unpublished data. Fish were the predominant ecological group of interest in most studies (125), followed by macroinvertebrates (33) and riparian vegetation (16). A higher number of studies documented ecological responses to natural flow variation (96) than anthropogenic-induced flow alterations (76) or reservoir operation improvements (12). A total of 58 of the 186 studies (31%) reported some type of linear or curvelinear relationship between changes in flow and ecology.
Ecological responses to natural flow variation were highly variable regardless of the direction and magnitude of changes in flow. One exception was drought, which was primary associated with more negative than positive ecological responses. In contrast to natural flow variation, ecological responses to anthropogenic-induced flow alterations were consistently negative regardless of the direction and magnitude in flow alterations. Reservoir operations were predominantly associated with negative ecological responses. Although the majority of ecological responses to flow alterations associated with urbanization, channelization, agriculture, and withdrawals were negative, some ecological groups showed variable responses. Fish tended to respond negatively to anthropogenic-induced flow alterations. Algae on the other hand tended to respond positively. Macroinvertebrates and riparian vegetation responses were primarily negative; however, responses in these ecological groups were more inconsistent. Although linear relationships between flow and ecology were common for natural flow variation and anthropogenic flow alteration studies, few generalized relationships could be drawn across all sources of information. Furthermore, our results suggest that using ecological relationships derived from natural flow variability to predict relationships between ecology and human-altered flow is limited and will require placing relationships in appropriate contexts, such as flow classes.
We used regression trees and random forests to determine what predictors were most important in determining the direction and magnitude of ecological responses to changes in flow. Our results suggested that ecological group and the source of flow change (natural versus anthropogenic) were the most important predictors of ecological responses. In addition, the degree of flow alteration (% change) and the flow sub-component were important predictors of ecological responses. Primary flow components (e.g. magnitude, frequency, duration, timing, and rate of change), study location (physiographic province), hydrologic resolution, and the nature of the flow-ecology relationships (direct or indirect) were less important in predicting the direction and magnitude of ecological responses. Our results also suggest that categorizing flow-ecology relationships by primary flow components (e.g.magnitude, frequency) lead to inconsistent trends. On the other hand, flow sub-components (e.g. floods, low flows) or environmental flow components (EFCs) are more descriptive and may provide more relevance in forming predictive flow-ecology relationships.
Our results suggested that the source of flow change and the ecological group of interest played primary roles in determining the direction and magnitude of ecological responses to changes in flow. Our results also suggest that if relationships between ecology and natural flow variation are to be used to predict ecological responses to anthropogenic-induced hydrologic alterations, they should be developed as relationships within specific contexts. For example, river classifications, based on flow and geomorphology or based on dam operation types, may stratify analyses into ecologically relevant relationships that increase predictive capabilities and inform management.
Although this study provides an initial framework to understand potential ecological responses to changes in flow, more research is needed to isolate quantitative, predictable relationships. Existing hypotheses regarding flow-ecology relationships should be refined and new hypotheses generated through future literature searches, meta-analyses, regional and basin-specific studies, as well as mesocosm studies. With growing water demands and the potential effects of climate change in the Southeastern US (Sun et al. 2008), water management will require developing frameworks to plan for sustainable water use, which depends on socially acceptable ecological conditions (Poff et al. 2010). Predicting population- and community-level changes to anticipated hydrologic alterations due to climate change and future water consumption will require developing structural linkages between sources of flow alterations, their impact on natural hydrology, and the resulting impact on ecology.
Prior to the US Forest Service’s purchase of the Glen Alton farm in 1998, cattle had unrestricted... more Prior to the US Forest Service’s purchase of the Glen Alton farm in 1998, cattle had unrestricted access to Stoney Creek in Giles County, VA. Loss of riparian vegetation caused stream bank failure, sedimentation, increases in stream temperature, and ultimately,a loss in trout habitat. In the spring of 2008, a joint collaboration was initiated between VDGIF, USFS, and TU (Trout Unlimited) to restore the degraded section of Stoney Creek. Main goals of the project were to reduce erosion, restore riparian vegetation, and enhance trout habitat. Tributaries with stable brook trout populations enter into the main stem of Stoney Creek above and below the degraded section; thus, improving habitat corridors within the main stem may lead to increased dispersal between brook trout populations. Proposals to Southeastern Aquatic Resources Partnership, National Forest Foundation, and Embrace a Stream (TU national) were awarded a total of over $36,000 to conduct the project. In the fall of 2008, project goals became a reality. Eroding banks were graded and seeded. Cross vanes were installed to redirect potentially erosive flows away from banks. Rootwads were embedded into bank walls to armor riparian soils. Lunker structures were built into banks to prevent erosion and provide cover for trout. Because of the proximity of Stoney Creek to Virginia Tech and the
opportunity for direct field experience, a stream restoration service learning class was created through the Fisheries and Wildlife Sciences Department. The goal was to educate students about the application and science of stream restoration. Students were able to assist in the habitat improvement by installing cover logs and helping to build a lunker structure. After students learned first hand how stream restoration is conducted, they created public education materials for use by VDGIF, USFS, and TU. Also, long term research through Virginia Tech has been initiated to monitor the influence of the restoration on the fish population and stream morphology. The research will not only assist in future management of Stoney Creek, but should also continue to provide Virginia Tech students with opportunities to learn about the field of stream restoration.
The ongoing Basin-Scale Opportunity Assessment (BSOA) Initiative, led by the U.S. Department of E... more The ongoing Basin-Scale Opportunity Assessment (BSOA) Initiative, led by the U.S. Department of Energy’s (DOE’s) Water Power Program, is establishing an integrative approach to assess complementary hydropower-environmental opportunities for selected river basins. Under the BSOA Initiative, Phase 1 Scoping Assessments are intended to provide initial identification, classification, screening, and integration of possible hydropower and environmental opportunities in a given river basin for DOE and basin stakeholders to consider carrying forward as appropriate. In fiscal year (FY) 2013, Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) developed a technical approach and methodology for BSOA Phase 1 assessments and performed preliminary assessments for the Connecticut River and Roanoke River basins.
Stakeholders are applying increasing pressure on many hydropower dam owners to change plant opera... more Stakeholders are applying increasing pressure on many hydropower dam owners to change plant operations to affect downstream river flows with the intention of providing better conditions for aquatic biological communities. These proposed changes often include a move away from peaking operations to lower value run-of-river operations based on the assumption that downstream biological communities will improve under more natural flow regimes. A reasonable compromise could be found by identifying those characteristics of sub-daily flow variation that are amenable to healthy aquatic communities and those that may not be conducive and using that information to identify possible mitigation opportunities that would continue to allow peaking operation. This paper reports on the results of an ongoing US Department of Energy funded study to assess the range of peaking operations across the nation, develop tools to characterize how peaking projects affect flow variability, and identify opportunities for enhancing environmental protection while maintaining peaking operations. Instead of characterizing peaking on a project by project basis, we classified peaking projects in conjunction with a nationwide river classification so that projects could be grouped by similarities in project and environmental attributes (e.g., reservoir storage, river flow, degree of peaking, etc.). To characterize flow alteration we identified several metrics that can be used to quantify flow variability on an hourly basis using readily available USGS gage data. The hydropower classification scheme and sub-daily flow metrics will be coupled with biological data to evaluate which aspects of daily and sub-daily flow variability could be targets for possible mitigation to reduce environmental risk.
Due to increasing domestic and international interest in hydropower, the goal of the symposium wa... more Due to increasing domestic and international interest in hydropower, the goal of the symposium was to highlight basin-scale initiatives, tools, and technologies to guide sustainable hydropower energy development and balance energy production with improvements to fisheries. Several initiatives were presented, including (1) the Penobscot River Restoration, where removal of dams was offset by increasing energy generation at remaining dams, leading to a net increase in energy production; (2) the Basin Scale Opportunity Assessment, an integrative approach for assessing mutual benefits between hydropower energy and environmental improvements within river basins; (3) the Hydropower Sustainability Assessment protocol, a standardized guidance for assessing best practices for the global hydropower industry; and (4) the Pacific Northwest Power Act, a multi-organization collaboration to balance the needs of fisheries with that of hydropower generation. Due to aggressive hydropower expansion in Brazil, one presentation discussed the importance of creating reserves for free-flowing rivers to ensure self-sustaining fish populations, as opposed to relying on ineffective mitigations. Another presentation discussed how dam locations should be arranged to optimize hydropower energy and ecological services, including American Eel survival. Other presentations included tools to balance multiple competing energy and environmental demands and new technologies including improvements in water quality, decreases in fish movement-related mortality, and 2D acoustic fish tracking.
As urban areas continue to grow and evolve in a world of increasing environmental awareness, the ... more As urban areas continue to grow and evolve in a world of increasing environmental awareness, the need for detailed information regarding residential energy consumption patterns has become increasingly important. Though current modeling efforts mark significant progress in the effort to better understand the spatial distribution of energy consumption, the majority of techniques are highly dependent on region-specific data sources and often require building-or dwelling-level details that are not publicly available for many regions in the United States. Furthermore, many existing methods do not account for errors in input data sources and may not accurately reflect inherent uncertainties in model outputs. We propose an alternative and more general hybrid approach to high-resolution residential electricity consumption modeling by merging a dasymetric model with a complementary machine learning algorithm. The method's flexible data requirement and statistical framework ensure that the model both is applicable to a wide range of regions and considers errors in input data sources.
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As a part of the Department of Energy (DOE) Water Power Program, the Instream Flow Project (IFP) was carried out by Oak Ridge National Laboratory (ORNL), Pacific Northwest National Laboratory (PNNL), and Argon National Laboratory (ANL) as an attempt to develop tools aimed at defining environmental flow needs for hydropower operations. The application of these tools ranges from national to site-specific scales; thus, the utility of each tool will depend on various phases of the environmental flow process. Given the complexity and sheer volume of applications used to determine environmentally acceptable flows for hydropower, a framework is needed to organize efforts into a staged process dependent upon spatial, temporal, and functional attributes. By far, the predominant domain for determining environmental flows related to hydropower is within the Federal Energy Regulatory Commission (FERC) relicensing process. This process can take multiple years and can be very expensive depending on the scale of each hydropower project. The utility of such a framework is that it can expedite the environmental flow process by 1) organizing data and applications to identify predictable relationships between flows and ecology, and 2) suggesting when and where tools should be used in the environmental flow process. In addition to regulatory procedures, a framework should also provide the coordination for a comprehensive research agenda to guide the science of environmental flows. This research program has further reaching benefits than just environmental flow determination by providing modeling applications, data, and geospatial layers to inform potential hydropower development.
We address several objectives within this document that highlight the limitations of existing environmental flow paradigms and their applications to hydropower while presenting a new framework catered towards hydropower needs. Herein, we address the following objectives: 1) Provide a brief overview of the Natural Flow Regime paradigm and existing environmental flow frameworks that have been used to determine ecologically sensitive stream flows for hydropower operations. 2) Describe a new conceptual framework to aid in determining flows needed to meet ecological objectives with regard to hydropower operations. The framework is centralized around determining predictable relationships between flow and ecological responses. 3) Provide evidence of how efforts from ORNL, PNNL, and ANL have filled some of the gaps in this broader framework, and suggest how the framework can be used to set the stage for a research agenda for environmental flow.
We found a total of 186 sources that provided a qualitative or quantitative relationship between flow and ecology within states encompassing the South Atlantic region. Of the sources, 128 were peer-reviewed published articles, 55 were grey literature, and 3 were unpublished data. Fish were the predominant ecological group of interest in most studies (125), followed by macroinvertebrates (33) and riparian vegetation (16). A higher number of studies documented ecological responses to natural flow variation (96) than anthropogenic-induced flow alterations (76) or reservoir operation improvements (12). A total of 58 of the 186 studies (31%) reported some type of linear or curvelinear relationship between changes in flow and ecology.
Ecological responses to natural flow variation were highly variable regardless of the direction and magnitude of changes in flow. One exception was drought, which was primary associated with more negative than positive ecological responses. In contrast to natural flow variation, ecological responses to anthropogenic-induced flow alterations were consistently negative regardless of the direction and magnitude in flow alterations. Reservoir operations were predominantly associated with negative ecological responses. Although the majority of ecological responses to flow alterations associated with urbanization, channelization, agriculture, and withdrawals were negative, some ecological groups showed variable responses. Fish tended to respond negatively to anthropogenic-induced flow alterations. Algae on the other hand tended to respond positively. Macroinvertebrates and riparian vegetation responses were primarily negative; however, responses in these ecological groups were more inconsistent. Although linear relationships between flow and ecology were common for natural flow variation and anthropogenic flow alteration studies, few generalized relationships could be drawn across all sources of information. Furthermore, our results suggest that using ecological relationships derived from natural flow variability to predict relationships between ecology and human-altered flow is limited and will require placing relationships in appropriate contexts, such as flow classes.
We used regression trees and random forests to determine what predictors were most important in determining the direction and magnitude of ecological responses to changes in flow. Our results suggested that ecological group and the source of flow change (natural versus anthropogenic) were the most important predictors of ecological responses. In addition, the degree of flow alteration (% change) and the flow sub-component were important predictors of ecological responses. Primary flow components (e.g. magnitude, frequency, duration, timing, and rate of change), study location (physiographic province), hydrologic resolution, and the nature of the flow-ecology relationships (direct or indirect) were less important in predicting the direction and magnitude of ecological responses. Our results also suggest that categorizing flow-ecology relationships by primary flow components (e.g.magnitude, frequency) lead to inconsistent trends. On the other hand, flow sub-components (e.g. floods, low flows) or environmental flow components (EFCs) are more descriptive and may provide more relevance in forming predictive flow-ecology relationships.
Our results suggested that the source of flow change and the ecological group of interest played primary roles in determining the direction and magnitude of ecological responses to changes in flow. Our results also suggest that if relationships between ecology and natural flow variation are to be used to predict ecological responses to anthropogenic-induced hydrologic alterations, they should be developed as relationships within specific contexts. For example, river classifications, based on flow and geomorphology or based on dam operation types, may stratify analyses into ecologically relevant relationships that increase predictive capabilities and inform management.
Although this study provides an initial framework to understand potential ecological responses to changes in flow, more research is needed to isolate quantitative, predictable relationships. Existing hypotheses regarding flow-ecology relationships should be refined and new hypotheses generated through future literature searches, meta-analyses, regional and basin-specific studies, as well as mesocosm studies. With growing water demands and the potential effects of climate change in the Southeastern US (Sun et al. 2008), water management will require developing frameworks to plan for sustainable water use, which depends on socially acceptable ecological conditions (Poff et al. 2010). Predicting population- and community-level changes to anticipated hydrologic alterations due to climate change and future water consumption will require developing structural linkages between sources of flow alterations, their impact on natural hydrology, and the resulting impact on ecology.
opportunity for direct field experience, a stream restoration service learning class was created through the Fisheries and Wildlife Sciences Department. The goal was to educate students about the application and science of stream restoration. Students were able to assist in the habitat improvement by installing cover logs and helping to build a lunker structure. After students learned first hand how stream restoration is conducted, they created public education materials for use by VDGIF, USFS, and TU. Also, long term research through Virginia Tech has been initiated to monitor the influence of the restoration on the fish population and stream morphology. The research will not only assist in future management of Stoney Creek, but should also continue to provide Virginia Tech students with opportunities to learn about the field of stream restoration.
approach for assessing mutual benefits between hydropower energy and environmental improvements within river basins; (3) the Hydropower Sustainability Assessment protocol, a standardized guidance for assessing best practices for the global hydropower industry; and (4) the Pacific Northwest Power Act, a multi-organization collaboration to balance the needs of fisheries with that of hydropower generation. Due to aggressive hydropower expansion in Brazil, one presentation discussed the importance of creating reserves for free-flowing rivers to ensure self-sustaining fish populations, as opposed to relying on ineffective mitigations. Another presentation discussed how dam locations should be arranged to optimize hydropower energy and ecological services, including American Eel survival. Other presentations included tools to balance multiple competing energy and environmental demands and new technologies including improvements in water quality, decreases in fish movement-related mortality, and 2D acoustic fish tracking.