The Daily – The Sunday Read: ‘The Trillion- Gallon Question’

Intro

In this episode of “The Daily,” the podcast explores the potential catastrophic failure of the Oroville Dam in California due to heavy rainfall. The episode delves into the outdated flood data used to design California’s dams, the risks of dam failures, and the need for better preparation for extreme weather events. It also discusses the efforts to improve dam safety and adapt to climate change.

Main Takeaways

The Risks of Outdated Dam Designs

• California’s dams were built using flood data from the mid-20th century, which did not account for the possibility of a warming atmosphere or larger floods.
• Many of California’s dams are embankment dams, which are vulnerable if water starts to flow over the top.
• If an even bigger series of storms hit California, it could lead to unprecedented destruction and flooding brought by a dam failure, with a wave of water taller than a tsunami.
• California needs to prepare for the possibility of dam failures and larger floods in the future.

The Oroville Dam Incident

• The Oroville Dam in California faced a potential catastrophic failure in 2017 due to heavy rainfall.
• An evacuation order affected as many as 180,000 people, including inmates from the local jail who were moved to another facility.
• The Independent Forensic Report blamed a “complacent culture” at the Department of Water Resources (DWR) for the incident.

The Need for Improved Dam Safety

• Dam operators across the country have started reassessing the structures under their control for hidden weaknesses.
• California’s dams are unprepared for extreme weather due to a false sense of how bad flooding can get.
• Flood data used for the design of California’s dams came from an unusually placid period in the state’s weather.

The Army Corps of Engineers and Dam Safety

• The Army Corps of Engineers plays a role in dams that receive federal funding and helps write the water control manual for each of them.
• The manual dictates when a dam should hold water during a flood and when it should release it, with one unbreakable commandment: a dam shall not be overtopped.
• The Army Corps has done a preliminary analysis on the impact of future extreme weather events on California’s largest reservoirs, with astounding results.

Adapting to Climate Change and Improving Dam Safety

• Forecast-informed reservoir operations (FIRO) allow for more water to be spilled in advance if a big storm is forecasted, and more water can be held back if meteorologists predict a dry spell.
• New spillway designs, such as the Ark spillway, aim to release water early when the river is low and hold it back during heavy rainfall.
• Learning from the past and unlearning outdated lessons could be the key to success in adapting to climate change and improving dam safety.

Summary

Outdated Designs and Dam Failures

California’s dams were built using flood data from the mid-20th century, which did not account for the possibility of a warming atmosphere or larger floods. Many of the state’s dams are embankment dams, which can be vulnerable if water starts to flow over the top. If an even bigger series of storms hit California, it could lead to unprecedented destruction and flooding brought by a dam failure. The Oroville Dam incident in 2017 highlighted the need for better preparation and dam safety measures.

The Risks of Inadequate Preparation

California’s dams are unprepared for extreme weather events due to a false sense of how bad flooding can get. The flood data used for their design came from an unusually placid period in the state’s weather history. Dam operators across the country are reassessing their structures for hidden weaknesses, but responsibility for dam safety lies with state and federal authorities, making it unclear if any entity can see the whole picture. The Army Corps of Engineers plays a role in dams that receive federal funding and has conducted analyses on the impact of future extreme weather events on California’s largest reservoirs.

Adapting to Climate Change and Improving Dam Safety

Adapting to climate change and improving dam safety require new approaches. Forecast-informed reservoir operations (FIRO) allow for more proactive water management based on weather forecasts. New spillway designs, such as the Ark spillway, aim to release water early when the river is low and hold it back during heavy rainfall. Learning from past mistakes and unlearning outdated lessons are crucial in successfully adapting to climate change and improving dam safety.

Conclusion

The potential failure of the Oroville Dam in California serves as a wake-up call for the need to reassess dam designs, improve dam safety measures, and adapt to the challenges of climate change. By learning from past failures and embracing new approaches, California can better prepare for extreme weather events and protect its communities from devastating flooding.