Managing Projects and Portfolios: Learning from Incidents and Assessments

Download Eli Wilson's presentation
Download Mark Christian's presentation
Presentations are:

Diablo Dam Trash Rack Replacement: Underwater Construction at 130 Feet, presented by Eli Wilson, Seattle City Light

Fleetwide Assessment of Hydropower Climate Risk, presented by Mark Christian, EPRI

Details about each presentation and the speakers are below:

Diablo Dam Trash Rack Replacement: Underwater Construction at 130 Feet,
presented by Eli Wilson, Seattle City Light

Trashracks are critical to hydro facilities, preventing debris from damaging turbines, yet they are often overlooked. Submerged and hard to access, they seldom appear in PFMA or L2RA assessments since failure rarely threatens public safety, but operational and financial risks can be severe. This presentation shares the costly experience of a utility whose sole trash rack was unexpectedly crushed. We will review the incident, including debris cleanup, investigation methods, and revenue losses from a full plant outage, before examining the redesign and reconstruction phases.

In design, we will cover constructability, reliability, hydraulic improvements, and the benefits of early contractor involvement. Key details include adaptable steel design, material and coating choices, and a tailored concrete mix. In construction, we will highlight the value of experienced partners, strategic staging, adapting to unknown conditions, permit challenges, underwater concrete placement, and a hold-point inspection plan to assure quality. Attendees will leave with lessons learned on what worked and what did not, better preparing them for future underwater projects.

Fleetwide Assessment of Hydropower Climate Risk,
presented by Mark Christian, EPRI

As climate change alters hydrologic patterns, it is vital to assess how this is likely to impact the operation and safety of hydropower plants. To support this, the authors develop site specific Hydrologic Key Performance Indicators (HKPIs) for 1,200 plants to quantify the risk to generation, flood control, irrigation, water supply, inland waterway navigation, environmental support, and recreation. Analysis was performed for four climate emission scenarios, each with 7 climate models, resulting in 28 data points for each site to provide insight into the spectrum of future risks. Results are aggregated at the basin level to specific site risk identification and are categorized as near term (2020-2059) and long term (2060-2099).

This analysis demonstrated that, while in many basins the drought risk was decreasing, there were several that indicated an increasing drought risk. The most notable of these is the Rio Grande Basin. Flood risk was indicated by the change in 100- and 1000-year flood severity as a ratio of the listed spillway size. While flood operations are a site-specific combination of drawdown, river coordination, and spilling, this study focused on the underlying criticality of being able to control water flow to prevent the dam from being overtopped. The study found that all basins had a median increase in flood risk however not every individual facility faced this increase. Additionally, an assessment to understand the impacts to Water Supply, Navigation, Environmental Support, Recreation, and Irrigation was performed. Results are designed to be coupled with site specific characteristics including plant criticality, risk, and condition to help inform more detailed site-specific studies to inform capital investments and emergency planning.

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