Commission summary, 8/9/2022 — Grant PUD to evaluate embankment at Wanapum Dam

Contractor to analyze dam embankment for possible erosion

Commissioners heard the details of a proposed, 10-year, $15 million contract with engineering firm Gannett Fleming to examine the interior of an embankment at Wanapum Dam for any potential erosion.

The last in-depth dam safety inspection by independent consultants in 2021 concluded that internal erosion, if severe enough, could lead to failure of the embankment. The analysis will show Grant PUD if any repairs are needed to keep the structure sound and safe.

The embankment is made of earth and rocks. At its core is a silty sand that limits the amount of water that passes through. The core is surrounded by layers of coarser-grained soils and protective rock. The embankment connects the concrete portion of the dam to the shoreline.

Evaluation of the embankment for potential internal erosion and seismic stability is a federal requirement. The evaluation will begin with existing data and use a phased approach, which could include drilling bore holes, to assess the embankment's stability.

Engineering Manager Becca Simpson told commissioners the embankment was built using the best practices available in the early 1960s, when the dam was built. The proposed analysis will determine if repairs are needed and their cost.

Work is already underway downriver to build a roller-compacted concrete wall just inland and parallel to the dam's existing earthen embankment on the Yakima County side of Priest Rapids Dam. The $54 million project is also a federal dam-safety requirement to ensure seismic stability.

Four companies bid on the contract for the Wanapum Dam embankment. Gannett Fleming, which has done extensive work for Grant PUD already, scored the highest.

Commissioners are scheduled to vote on the proposed contract at their Aug. 23 meeting at Grant PUD's Ephrata Headquarters.

Hear the full discussion at 1:07:16 on the commission audio. View the presentation on pages 1-28 of the presentation materials.

Commissioners also:

-- Heard that Grant PUD, along with other Washington utilities have worked together to develop a standard template for calculating the cost burden associated with the state's "Climate Commitment Act," a "cap-and-invest" mandate to reduce greenhouse gas emissions in the state's energy supply.

The state Department of Ecology has until October 1, 2023 to adopt final rules that will include an allocation of "no-cost" allowances to utilities to help offset their cost burden during the act's first compliance period, from 2023 to 2026, Rich Flanigan, senior manager of Wholesale Power Supply, told commissioners.

Grant PUD used its Integrated Resource Plan, Clean Energy Implementation Plan, and other relevant information to calculate its cost burden during the 2023-2026 period.With the implementation of the Climate Commitment Act, there is an additional cost associated with the carbon-containing portion of Grant PUD's energy supply that could increase customers' electric rates.

Commissioners will review the cost-burden analysis and are scheduled to vote on it during their Aug. 23 meeting at Grant PUD's Ephrata Headquarters. Once approved, Grant PUD will wait to hear how the state Department of Ecology allocates no-cost allowances to help utilities defray the added costs.

"The rules are not completely finalized, so it's difficult to understand the impacts," Flanigan said. "This effort is to mitigate costs we believe we'll incur."

Hear the full discussion at 1:38:30 on the commission audio. View the presentation on pages 11-19 of the commission packet.

-- Got a quick look at the preliminary 2023 budget and heard that inflation will be a large cost driver.

Inflation is expected to increase overall maintenance and operations costs. Supply chain delays, international food and energy markets, and highly constrained labor markets will continue to drive inflation through 2023, Senior Manager of Financial Planning and Analysis John Mertlich told commissioners.

State law requires the preliminary budget be filed with the state this month. The first refined draft of the 2023 budget will be ready for commission review in late September. Public hearings on the 2023 budget will happen in October. Commissioners are expected to adopt the 2023 budget Nov. 11.

Hear the full discussion at 1:57:50 on the commission audio. View the presentation on pages 29-35 of the presentation materials

-- Heard a summary of the Power Delivery Construction and Maintenance team's efforts through June to hire qualified technicians, linemen, engineers and electricians and continue work on projects to improve the quality and supply of electricity for Grant PUD customers. Hear the full discussion at 2:17:35 on the commission audio. View the presentation on pages 36-47 of the presentation materials

-- Heard about key state and federal legislative issues the utility has been tracking. Federally, the government affairs group is collaborating with other internal departments to explore federal funding opportunities via the Infrastructure Investment and Jobs Act. Federal agencies continue to establish potential programs and various requirements that the utility will continue to review. See the full presentation of key issues on pages 76-91 of the commission presentations