David Vance and Robert Dunn to Present at Stream Restoration 2022
David Vance, P.G., and Robert Dunn (Georgia) will present on stream restoration at the National Stream Restoration Conference at the Gaylord Opryland Resort in Nashville, Tennessee, on August 1–2, 2022.
David Vance is a Principal Geologist based in Georgia with more than 18 years of experience restoring riverine and coastal systems. A fluvial geomorphologist and ecosystem restoration scientist, David focuses on rivers and coastal systems, their processes, and the ecosystems they support. He manages projects and serves as technical lead for geomorphic assessments and technical studies, from site assessments and remedial designs for linear (hydrotechnical focus) and nonlinear projects (mitigation bank development and restoration design) to watershed-scale and multistate assessments for pipeline projects spanning entire regions.
Bobby Dunn is a water resource scientist and aquatic ecologist with natural resource and ecological consulting experience in streams, rivers, lakes, and coastal ecosystems. He has applied principles of biology ecology, and natural resource management to a range of projects but his passion lies in ecosystem assessment and restoration, particularly fluvial ecosystems. Mr. Dunn's practice in fluvial geomorphology has largely focused on the interaction of fluvial systems (riverine or coastal) and infrastructure and has supported clients in evaluating and mitigating the risks and hazards of fluvial systems on the built environment.
The First National Stream Restoration Conference, presented by the Resource Institute, is made up of sessions that focus on prior and current projects, specific examples, success stories, and lessons learned to advance stream and wetland restoration.
The Resource Institute protects and enhances water resources through restoration, education, and project management. Its mission is to enhance America's natural resources by restoring streams, rivers, and wetlands.
Survey and Assessment Technology (UAVs & Photo Software) & Hydrologic and Hydraulic Modeling
Presenter: Robert Dunn
Time and Date: 1:50 p.m. EST on August 1, 2022
Traditional stream survey methods have long been the preferred method for river ecosystem assessment and monitoring. However, topographic surveys that use newer methods (UAVs, ground-based lidar, survey-grade RTK GPS, etc.) are increasingly becoming more common in river ecosystem assessment and restoration monitoring. UAVs equipped with high-resolution lidar scanners offer a suite of benefits for river restoration practitioners, including increased spatial coverage and data density, allowing practitioners to repeatedly collect topographic and geomorphic data beyond the traditional reach-scale, with less time than traditional methods. Further, the repeated acquisition of high-resolution topographic surveys over a river ecosystem allows assessment and/or monitoring of geomorphic change to be expanded spatially beyond reach-scale cross-sections and longitudinal profiles.
Employment of Geomorphic Change Detection (GCD) methods to repeat high-resolution topographic surveys of a river system allow practitioners to better understand the geomorphic rate and magnitude of change and how this relates to stream-system processes influencing form and function of a river system, especially in post-restoration scenarios. This presentation will highlight the use of UAVs to collect high resolution aerial data (lidar and photogrammetry) during pre- and post-peak flows along 15 river miles to evaluate ecosystem response and impacts. The repeat topographic surveys were used in the GCD software to generate spatially distributed maps of elevation, volume and areal change, which portray a detailed depiction of the magnitude and extents of change at both the reach scale and river scale. The presentation will include lessons learned, successes, and failures in the use of UAVs and aerial data for river ecosystem assessment and monitoring.
A New Flow Regime, Ethics, and Beavers: A 30-Year Story of Eastern Sierra Stream Restoration and an Uncertain Future
Presenter: David Vance
Time and Date: 9:10 a.m. EST on August 2, 2022
How will a stream and its biology respond to a change in flow regime? Will the new flow regime achieve long-term restoration objectives for over 15 miles of high and low gradient streams? Two main Eastern Sierra Nevada stream systems (Rush and Lee Vining Creeks) have been under mandated restoration for over three decades with substantial progress in ecosystem recovery. With ecosystem recovery having reached an asymptote, a shift in flow regime was proposed by state-appointed "stream scientist," a non-governmental organization, and was supported by a closely aligned state regulator.
At the time, there were limited geomorphic justifications and proofs for the new flow regime other than broad biologically centric hypotheses and assumptions. The new flow regime increased overall peak snowmelt bench and flood durations and magnitudes which led to questions of geomorphic stability (by the authors) for both systems. Therefore, we sought to quantify the geomorphic response of the stream systems to the new flow regime and resulting consequences. Our team developed a novel long-term bed degradation analysis to evaluate the average long-term bed degradation for existing and proposed flow regimes, using recent and historical geomorphic and hydrologic data to quantify the difference in bed degradation potential between the two flow regimes approximately 30 years into the future at the reach-scale with and without the effects of climate change under four scenarios.
The state regulator and state-appointed stream scientists maintained their advocation for the new flow regime even though it was not supported by this study, historical watershed conditions, or available hydrology. Given the uncertainty of the multidecade drought in the west and future watershed hydrology, the attention is now on a family of beavers who are recolonizing within the stream systems. Their presence has coincided with selective aggradation, avulsion, and selective expansion of riparian habitat following the 2017 runoff year. It's the authors' hope that the beaver's habitat expansion will provide a mitigating factor against the degradation quantified in this study and that they will be the unlikely heroes of this ecosystem recovery story.
About the event: Stream Restoration 2022
About the Resource Institute: https://www.resourceinstituteinc.org/
Learn more about David: https://www.geosyntec.com/people/david-vance
Learn more about Robert: https://www.linkedin.com/in/robert-dunn-9878b9a4/
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