October 22, 2025, Vancouver, BC, Canada – Knight Piésold Canada featured the Klamath River Renewal Project in a special session at the Canadian Dam Association (CDA) Annual Conference and Trade Show, held at TCU Place in Saskatoon, Saskatchewan, from September 28 to October 1. The company also participated as a gold-level sponsor and exhibitor, fostering collaboration with dam professionals across Canada and internationally.

The conference, themed “Good Dams Make Good Neighbours,” brought together over 500 dam operators, regulators, consultants, suppliers, and academics to address technical challenges and share innovative solutions. Topics included dam safety, public safety, dam breach analysis, dam rehabilitation, and emerging industry practices.

Special Session on the Klamath River Renewal Project

Knight Piésold’s special session, delivered in partnership with Northwest Hydraulic Consultants (NHC), included five presentations on the largest dam removal and river restoration project in U.S. history. The project involved removing four aging hydroelectric dams (J.C. Boyle, Copco No. 1, Copco No. 2, and Iron Gate) along the Klamath River in southern Oregon and northern California to restore natural flow and volitional fish passage to historic habitat and spawning grounds. Knight Piésold served as the lead designer for Kiewit Infrastructure West Co. (Kiewit), developing innovative designs for safe dam decommissioning under a progressive design-build contract with the Klamath River Renewal Corporation (KRRC).

Project Overview

Craig Nistor, a specialist geoscientist at Knight Piésold, opened the session with “Klamath River Renewal Project,” a paper co-authored with Scott Rees of Knight Piésold and Laura Hazlett and Olivia Mahony of KRRC. Nistor gave a project overview and introduced the series of papers related to reservoir drawdown outlet design, reservoir water level modelling during drawdown, and analysis of the final dam breach.

Drawdown Modelling for the Iron Gate Dam

Nancy Sims, a principal hydraulic engineer at NHC, presented “Drawdown Modelling of Four Reservoirs on the Klamath River to Support Hydroelectric Facility Decommissioning.” The paper was co-authored by Todd Bennett and Jeremy Paine of NHC, Craig Nistor of Knight Piésold, and Alana Shewan of Ontario Power Generation (formerly of Knight Piésold). Sims’ presentation focused on drawdown modelling scenarios at Iron Gate Dam, comparing predicted outcomes with actual conditions observed during reservoir drawdown and dam removal activities.

Dam Modification Design for the Copco No. 1 Dam

Benoit Otis, a specialist engineer at Knight Piésold, delivered insights on “Design of Dam Modification for Reservoir Drawdown, River Diversion and Dam Removal of the Copco No. 1 Dam,” a paper co-authored with Carlo Capucao of Knight Piésold. Otis presented a summary of the hydraulic and dam stability studies completed to design outlet works required for Copco No. 1 reservoir drawdown and Klamath River diversion during dam removal operations.

Computational Fluid Dynamics Analysis for the Iron Gate Dam

Carlo Capucao, a senior engineer at Knight Piésold, presented the paper “Optimization of the Iron Gate Dam Historic Diversion Tunnel Using CFD Analysis to Support Reservoir Drawdown,” co-authored with Katrina Wechselberger of Knight Piésold. Capucao outlined the design development process for making tunnel modifications fit for purpose, highlighting where Computational Fluid Dynamics analysis provided valuable support throughout the process.

Dam Breach Analysis for the Iron Gate Dam

Daniel Adria, a project engineer at Knight Piésold, concluded the session with “Dam Breach Analysis Used for Designing the Final Breach of the Iron Gate Dam.” The paper, co-authored by Violeta Martin, Nick Rong, and Katrina Wechselberger of Knight Piésold, described the final phase of dam removal, which required a planned breach to release the remaining reservoir volume without causing downstream flooding.

Advancing Dam Engineering

Dam removal was completed in October 2024, with salmon observed to have migrated upstream within weeks of completion. “The restoration of over 400 stream-miles of salmon habitat was an incredibly proud moment for our team and the many who have contributed to this project over the past two decades,” said Nistor.

Nistor added, “Throughout six years from initial progressive design-build starting in 2019, through to the final dam removal in 2024, we worked in close collaboration with Kiewit and KRRC, alongside NHC and other specialized subconsultants. These papers represent our collective efforts from initial discussions through rigorous analysis, innovative design, and successful decommissioning.”

“Sharing our experience on this award-winning project at the CDA conference provided an opportunity to showcase our dam decommissioning capabilities,” Nistor concluded. “With our expanding portfolio of full lifecycle dam services, we support our clients throughout every phase of their dam projects, reinforcing our position at the forefront of this evolving industry across Canada and internationally.”