Risk-Informed Design in Practice: Lessons from the North Stockton Levee System

A Q&A with Jesse Morrill-Winter, Sr. Risk Consultant

Jesse Morrill-Winter brings more than a decade of experience in flood risk management, levee safety, and risk-informed decision making to his role at GEI Consultants. His work has focused on understanding how levee systems perform under complex loading conditions, how failures translate into real-world consequences, and how engineers and decision makers can use risk to guide smarter, more defensible investments. With a background spanning levee safety policy, national-level risk assessments, and the application of consequence modeling tools used both domestically and internationally, Jesse has worked at the intersection of technical analysis and public safety.

As part of GEI’s Levee Services campaign, Jesse sat down to discuss lessons from the North Stockton Levee System—an early application of risk-informed design in California’s Central Valley. The conversation explores why understanding risk early matters, how risk-informed approaches can shape design and investment decisions, and why collaboration and clear communication are essential to managing flood risk in complex, highly developed systems. His insights highlight how risk-informed design helps levee owners move beyond prescriptive solutions to make decisions that balance safety, performance, cost, and constructability.

Q: Can you briefly describe the North Stockton Levee system and why risk-informed decision making is especially important for a system like this?

A: The North Stockton Levee System is part of a highly complex flood risk management environment in California’s Central Valley and Delta. These systems are influenced by multiple loading sources, including riverine flooding, upstream reservoir operations, and interconnected channels, while also protecting densely populated, heavily developed areas.

What makes systems like North Stockton particularly well-suited for a risk-informed approach is that they function as interconnected systems, not isolated structures. Flood risk isn’t driven by a single failure mode or location; it emerges from how hydraulics, levee performance, operations, emergency response, and consequences interact. Risk-informed decision making helps ensure we understand those interactions and focus attention on the areas that matter most for reducing flood risk to people, property, and critical infrastructure.

Q: When work began on the North Stockton system, what were the key risks that needed to be understood before decisions could be made?

A: A critical early step was understanding what was actually driving risk, not just where design features were already planned. In this case, higher-resolution hydraulic modeling revealed that flooding could occur through a low point in a channel before levees were even stressed to the point of failure.

That insight fundamentally changed how the team thought about risk. If water can enter the protected area without a breach, then strengthening levees alone may not meaningfully reduce risk. Identifying that condition early allowed the team to align design decisions with the true drivers of flood risk, rather than assumptions based solely on traditional failure scenarios.

Q: How did a risk-informed approach influence how actions and investments were prioritized?

A: Risk-informed decision making encourages teams to go from big to small, starting with the factors that contribute most to risk and narrowing focus as uncertainty is reduced. For North Stockton, that meant confirming whether proposed design elements were addressing the dominant risk drivers.

In some cases, risk analysis showed that certain design features were unlikely to meaningfully reduce risk relative to their cost. That created an opportunity to simplify designs, reallocate resources, and focus on improvements providing the greatest risk reduction per dollar invested. This approach supports better investment decisions while maintaining safety and performance objectives.

Q: How did risk considerations influence design decisions and alternatives?

A: Risk-informed design played a key role during pre-construction engineering and design, when uncertainty is still significant but decisions have real cost and constructability implications. By evaluating failure modes, hydraulic behavior, and consequences together, the team could distinguish between areas where risk reduction was essential and areas where designs may have been overly conservative.

Rather than applying a one-size-fits-all solution, the design was refined to address specific concerns such as internal erosion, overtopping potential, and system hydraulics, while avoiding unnecessary complexity where it wouldn’t materially reduce risk.

Q: In what ways did risk-informed design help balance safety, performance, cost, and constructability?

A: At its core, risk-informed design is about risk tolerability: finding the balance between reducing flood risk and delivering practical, affordable, and buildable solutions.

There are two fundamental ways to reduce flood risk: reduce the likelihood of flooding, or reduce the consequences when flooding occurs. Risk-informed design helps teams evaluate both paths and identify where investments will have the greatest impact. In doing so, it often leads to solutions that are safer, more targeted, and less invasive—while improving constructability and cost certainty.

Q: Why is collaboration between engineers, regulators, and owners so important when applying risk-informed decision making?

A: Risk-informed approaches only work when communication and collaboration are treated as core elements of the process. Engineers, regulators, and owners each bring different priorities, constraints, and perspectives to the table, and aligning those early is essential.

Technical analysis alone isn’t enough. Decision makers need risk information translated into insights they can use, supported by transparent assumptions and clear visuals. When collaboration happens early and often, it builds trust, improves buy-in, and helps avoid late-stage surprises that can derail projects.

Q: What lessons from the North Stockton Levee system would you share with other levee owners?

A: The most important lesson is the value of front-loading risk-informed decision making. Understanding what drives risk early, before designs are finalized or costs are locked in, can save time, reduce uncertainty, and lead to better outcomes.

Risk-informed approaches also improve communication. When owners can clearly explain why certain investments matter more than others, it becomes easier to engage stakeholders, justify funding decisions, and move projects forward with confidence.

Q: If there’s one thing decision makers should understand about risk-informed design, what would it be?

A: Risk-informed design helps decision makers maximize the return on every dollar spent. By focusing first on the actions that reduce risk, teams can deliver meaningful improvements sooner, build efficiencies into long-term programs, and make defensible decisions under uncertainty.

Ultimately, it’s about making smarter choices to protect communities, respect limited resources, and support resilient flood risk management systems over time.