The dramatic spillway failure at Oroville Dam sparked a national conversation around the status of dams throughout the West. But dams are just one small part of the “gray” infrastructure designed to control flows, hem in rivers and transport water around the state. California’s flood and water-management system needs an overhaul to address everything from eroding levees to parched Central Valley aquifers and collapsing ecosystems.
The head-spinning swing from drought to flood falls right in line with predictions from climate scientists. These shifts between extreme weather events raise an important question: How should California invest in water infrastructure to protect us from floods and droughts?
Scientists tell us that California will receive less snow and more rain. As we face more intense and warmer storms, we must prepare for larger and more frequent floods interspersed with deeper and longer droughts than we’ve experienced over the past century.
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How do we meet this challenge? The best solution is on our doorstep. The Yolo Bypass, across the river from Sacramento, was designed in the early 1900s to allow floods to pass around the city. Several times this winter, floodwaters have been diverted onto the Yolo floodplain, keeping Sacramento residents safe and dry.
Decades of science has shown that floodplain projects designed to reconnect rivers to strategic portions of their floodplains give rivers more room and produce a range of benefits:
▪ Protects communities from catastrophic floods.
▪ Allows dam operators to safely release more water during floods, which increases flexibility and maximizes winter water storage for release in dry periods.
▪ Restores floodplain and wetland habitat for waterbirds, salmon and smelt.
▪ Recharges critical groundwater aquifers.
▪ Preserves agricultural land, allowing willing farmers to grow crops in the summer and provide habitat for birds and fish during winter.
▪ Creates recreational opportunities.
In recent years, quiet progress has been made toward expanding this multibenefit floodplain model throughout California. On the Feather River, levee setbacks, built by the Three Rivers Levee Improvement Authority, safely accommodated recent releases from Oroville Dam, keeping people safe while providing a refuge for wildlife. Flood-prone Napa stayed dry through these record rains thanks to a recently completed floodplain project. Upstream in the Sacramento Valley, Hamilton City will soon be protected by the first multibenefit floodplain project to be designed by the U.S. Army Corps of Engineers.
Closer to home, the Lower Elkhorn levee setback project will increase the capacity of the Yolo Bypass, dramatically improving flood protection for 780,000 Sacramento-area residents while creating 1,800 acres of critical floodplain habitat.
Even in dry years, intentionally inundated floodplains have been shown to grow fatter and healthier juvenile salmon and provide food and natural areas for the densest concentrations of migratory waterbirds in the West.
The Department of Water Resources’ recently released Conservation Strategy shows how multibenefit projects can serve as the foundation of the new Central Valley Flood Protection Plan. The plan will be finalized this year.
Some water-policy challenges involve tough decisions and strong disagreements. There’s an old adage about California water: “Whiskey is for drinking. Water is for fighting.” But building a 21st century water system for California doesn’t need to cause a fight. The best flood-protection projects also provide myriad other benefits for agriculture, fish, birds and improved water security for Southern California. Support for this approach is growing among farmers, the fishing industry, conservation groups, scientists, and flood and water agencies.
Carefully designed floodplain projects represent the smart way forward. This year should be the turning point toward safer and greener water infrastructure to prepare us for a warmer and less-predictable future.
Jacob Katz is a senior scientist with California Trout and can be reached at firstname.lastname@example.org. Brian Stranko is the director of The Nature Conservancy’s California Water Program and can be reached at email@example.com.