Fish Passage Workshop
CLEAN CURRENTS 2025
Time: 1:30 PM - 5:30 PM
Day: 10/14/2025
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Presentations are:
Advances in AI-Assisted Fish Counting at Hydroelectric Facilities using BlueFish, presented by Elliot Koontz, Four Peaks Environmental Science & Data Solutions
Blewett Falls Spillway Modifications and Eel Passage Project, presented by Mike Abney, Duke Energy, and Jesse Waldrip, Kleinschmidt Associates
Fishheart: An Innovative Technology for Passing Fish Upstream at Hydropower Dams, presented by Steve Amaral, Biopassage Scientific Consulting LLC
Numerical Investigation of Existing and Proposed Fish Passage Facilities using Computational Fluid Dynamics, presented by Adrian Strain, HDR
Collaborative Upgrade at Garvins Falls: A Model for Maintaining Energy Production and Addressing Downstream Passage Requirements with FishSafe turbines, presented by Abe Schneider, Natal Energy
HydroAI: Real-Time Fish Counts & Speciation for Better Compliance and Mitigation at Hydropower Sites, presented by Peter MacLeod, Innovasea Fish Tracking
Details about each presentation and the faculty are below:
Advances in AI-Assisted Fish Counting at Hydroelectric Facilities using BlueFish, presented by Elliot Koontz, Four Peaks Environmental Science & Data Solutions
Many hydropower facilities have ongoing fish counting requirements imposed by the U.S. Endangered Species Act. While these operations provide essential data for conservation and management, they are often conducted manually from video footage or “live” by in-person fishery observers. The current processes involve large costs to dam operators and can introduce data errors from observer inaccuracy.
This presentation will discuss a computer-vision camera system trained to count and classify fishes that is being jointly developed by Four Peaks Environmental Science & Data Solutions and MarineSitu. This technology has been trained, calibrated, and used in production counting at sites on the Columbia River and offers the potential to reduce observation times significantly while improving count data accuracy. The current system includes detecting, classifying, and counting fish on an edge computer, and uploads detection data and media to the cloud. Fishery observers then access photos of passage events through BlueFish, a software that allows them to efficiently classify images to finer categories and produce a count total for a period of time for reporting. The system also uses a continuous maintenance model that allows it to be retrained on a regular basis to adapt for changing site conditions.
We will discuss lessons learned from certain run conditions and species behaviors, how these obstacles will be tackled, and present results from case studies of the technology in the Pacific Northwest. Recent model developments have demonstrated species-level classification accuracies reaching 90% for Pacific salmonids for certain assemblages. We will also discuss future avenues of development supported by the Department of Energy, including underwater counting, stereo optics for more precise length estimation, and enumeration of juveniles. Ultimately, we hope that this technology can help improve fishery observation in multiple environmental contexts and continue to inform conservation efforts around dam operations.
Blewett Falls Spillway Modifications and Eel Passage Project, Mike Abney, Duke Energy, and Jesse Waldrip, Kleinschmidt Associates
Duke Energy’s Blewett Falls Hydroelectric Station is located on the Yadkin-Pee Dee River near Rockingham, NC. This hydroelectric station is about 115 years old and consists of a concrete gravity dam, earthen embankment, reservoir, power canal, and powerhouse. The concrete gravity dam stands approximately 50-feet-tall and 1,409-feet-long and holds back the 2,860-acre Blewett Falls Lake. A power canal adjacent to the dam leads to the powerhouse, which contains six turbine-generator units and has a total generating capacity of up to 24 megawatts.
For the past eight years Kleinschmidt Associates has been providing Duke Energy with engineering and regulatory support for a series of upgrades at the Blewett Falls site. The upgrades were driven by Federal Energy Regulatory Commission (FERC) license compliance requirements to provide upstream and downstream fish passage at the site and to provide modifications to the concrete dam to increase its stability to accommodate current seismic design specifications. The site upgrades consist of the following major elements:
1. Installation of new rock anchors at the dam/spillway,
2. Installation of new inflatable crest gates at the dam/spillway,
3. Installation of new downstream fish passage features at the dam/spillway, and
4. Installation of a new upstream eel passage facility at the dam/spillway.
In support of this work Kleinschmidt has worked with Duke Energy to performed alternatives analysis, conceptual design, agency/stakeholder consultation, detailed engineering analysis and design, development of construction drawings and technical specifications, development of FERC submittals, development of operation and maintenance plans, preconstruction planning, bidding and procurement support, full-time on-site construction support, and start-up and commissioning support. Construction of the upgrades required overcoming some significant challenges such as a prolonged duration of work on an active spillway.
This presentation will provide a summary of the recent upgrades at the Blewett Falls Hydroelectric Station, the technical challenges encountered by the Duke Energy/Kleinschmidt project team, the innovative solutions that were developed, and a review of the first two years of successful operation.
Fishheart: An Innovative Technology for Passing Fish Upstream at Hydropower Dams, presented by Steve Amaral, Biopassage Scientific Consulting LLC
Providing effective upstream passage at hydropower dams in in the U.S. and Canada is a top priority for resource agencies as part of their efforts to protect, restore, and enhance freshwater and diadromous fish populations. Target species and life stages vary across geographic regions and there may be a wide range of sizes and swimming abilities that need to be accommodated at any given project. Many existing conventional fish passage designs installed at hydropower dams have not met goals for safe, timely, and effective passage. For projects without upstream passage, the installation of new facilities can be an economic burden to many dam owners, costing in the range of $5 million to $20 million for installation with additional recurring costs for operation and maintenance. As an alternative to traditional upstream passage fishway designs, Fishheart Ltd (based in Finland) has developed a new innovative and comprehensive solution for passing fish upstream at dams. The Fishheart is a floating system installed in the tailrace that uses pumped attraction flow to bring fish into passage conduits for transport to the head pond. The Fishheart system has been accepted for upstream passage of salmonids in Finland and is currently being investigated as a method for passing freshwater fish species in Australia.
Additionally, a DOE-funded study led by EPRI was conducted at Santee Cooper’s Santee Dam in South Carolina in 2024 and the results of the evaluation demonstrated the Fishheart’s ability to pass a wide range of species (16 total) and sizes (from about 75 to 1,400 mm in length), including anadromous American Shad and river herring. Another study will be conducted at a hydropower project in Connecticut in the spring of 2025. The data and information obtained during these studies will be used to inform the design and operation of the Fishheart for future use with various freshwater and migratory fish species that are common to river systems in the U.S. and Canada.
Numerical Investigation of Existing and Proposed Fish Passage Facilities using Computational Fluid Dynamics, presented by Adrian Strain, HDR
As the need to hydraulically assess existing fish passage facilities and effectively evaluate potential designs becomes more prevalent, three-dimensional (3D) hydraulic model development, specifically computational fluid dynamics (CFD) modeling, has become more widely used in fish passage projects. By resolving the flow fields three-dimensionally, CFD offers an opportunity to further understand complex hydraulic conditions as flow approaches, passes through, and exits fish passage facilities. The fully resolved flow fields can be used to identify possible hydraulic barriers, refine designs, and evaluate mitigation alternatives. Two recent project examples highlight the use of CFD at fish passage facilities, showing how 3D modeling can be useful for both evaluation and design.
At the Essex 19 Hydroelectric Project on the Winooski River in Essex Junction, Vermont, CFD was used to characterize existing conditions hydraulics at the downstream facilities and evaluate potential fish passage designs for American Shad, Herring, and more. CFD models were developed at specific areas of interest and included the powerhouse forebay, fish sluice, and plunge pools. All areas were evaluated for velocities and flow patterns, and a graphical representation was used to determine adequacy of existing or potential fish passage designs.
The second example is an assessment of the design of a vertical slot fishway off the Sacramento River in Sacramento, California. CFD modeling was used for fishway design evaluation for potential green sturgeon passage with a velocity-focused analysis. Model results were used to identify areas of high velocity by assigning a velocity threshold specific to green sturgeon. Multiple iterations of design were evaluated and coordinated with local agencies to minimize areas of high velocity, particularly at locations where the velocity threshold was exceeded.
The use of CFD and other 3D models can provide additional insight to provide more confidence in model results, design elements, and whether fish passage criteria are met at a specific project site. The information from the CFD models can help facilitate useful discussion among agencies and outside stakeholders, as well as potentially reduce construction costs by evaluating proposed design to help meet effective fish passage criteria.
Collaborative Upgrade at Garvins Falls: A Model for Maintaining Energy Production and Addressing Downstream Passage Requirements with FishSafe turbines, presented by Abe Schneider, Natal Energy
Garvins Falls, a 12.4 MW hydropower project on the Merrimack River owned and operated by Patriot Hydro, faced significant downstream fish passage challenges for migratory fish species including American eel, American shad, blueback herring, and alewife.
The owner has been working with regulatory agencies to improve downstream passage, and agencies initially prescribed fine exclusion screens with ¾” clear spacing and a dedicated fish bypass as a mitigation measure at the project. However, there is a lack of examples of such screens being installed at a plant of Garvins’ scale (5,000 cfs), and there are many potential risks associated with their operation, including head loss, clogging or damage from debris and ice, increased operating costs, and increased risk to human safety.
Recognizing these challenges, Patriot partnered with Natel Energy to explore an innovative alternative: achieving high downstream fish survival through new specially-designed runners, while leaving most of the existing hydropower turbines (such as generators, draft tubes, general water passageway) unchanged. This presentation will detail the collaborative process between Patriot and Natel, highlighting the lessons learned in designing and implementing FishSafe turbine upgrades across Garvins' diverse turbine configurations. We will discuss the unique challenges encountered, such as adapting to multiple turbine designs (horizontal S-type Kaplan and vertical propeller) within a single facility, and how Natel's 3D modeling of water passageways and tailor-made runner geometries that incorporate thick and forward-swept leading edges, provided a solution. Crucially, we will emphasize the process of working with regulatory agencies to gain acceptance of this novel fish passage solution.
Patriot, Natel and the agencies are working together to finalize the implementation schedule for the FishSafe upgrades at Garvins, and are beginning to assess feasibility of FishSafe upgrades to solve downstream passage problems at other nearby hydropower stations as well. This project serves as a replicable model for balancing environmental stewardship with hydropower generation. This presentation will be co-presented by representatives from Patriot and Natel, providing a comprehensive perspective on the project's development and implementation.
HydroAI: Real-Time Fish Counts & Speciation for Better Compliance and Mitigation at Hydropower Sites, presented by Peter MacLeod, Innovasea Fish Tracking
HydroAI combines optical cameras with cloud-based AI processing to count and speciate fish in real time, streamlining compliance and mitigation for hydropower operators. Currently deployed at 11 sites across three major power producers in eastern Canada, the system has supported upstream alewife counts for Nova Scotia Power and salmon monitoring for New Brunswick Power. It adapts to various fish bypass applications including pool-and-weir, upstream fish lifts, and downstream bypasses.
HydroAI records fish on-site, counts them, and transmits data to a live dashboard in real time. By counting every fish passing the dam, operators gain key insights that they can use for operational decision-making, such as first/last fish of the season, day/night distribution, and peak travel times. Operators have also paired HydroAI with acoustic telemetry for a fuller picture of how the fish are interacting with their dam infrastructure.
We are keen to chat with operators about how HydroAI can resolve their unique fish counting challenges.
Presenters
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