Topic: Levees



California would not exist as it does today were it not for the extensive system of levees, weirs and flood bypasses that have been built through the years, particularly in the Sacramento-San Joaquin Delta.

Aquafornia news Sacramento Bee

Sacramento flood work to remove American River Parkway trees

A community group is worried a project to strengthen levees in Sacramento will lead to the removal of several hundred trees along the American River Parkway, creating long-lasting environmental effects while damaging a popular regional recreation area. The community group, American River Trees, is specifically concerned about a portion of the levee upgrade project by the U.S. Army Corps of Engineers known as the “Contract 3B site,” where erosion protection measures will be constructed upstream of Howe Avenue along the river to Watt Avenue. … Project officials said the upgrades are needed to “armor the riverbank to reduce and prevent erosion which, if left unaddressed, could result in levee failure.” William Avery, a Sacramento State biology professor emeritus and a member of American River Trees group … said the project plans call for the removal of about 500 trees south of the river and about 200 trees on the north side …

Aquafornia news Los Angeles Times

How freeing rivers can help California ease flood risks and revive ecosystems

… Natural floodplains — the lush green lands along rivers that historically flooded, retained water, and nourished life in the heart of the valley — were mostly drained and converted to farmland generations ago as the state’s waters were dammed and diverted. Today, an effort to bring back some of those floodplains is flourishing at the 2,100-acre Dos Rios Ranch Preserve near Modesto, where workers years ago planted native trees on retired farm fields and removed berms to create space for water to spread out again. … By making room for the rivers to overflow, the restoration project has created an outlet for high flows that helps to reduce the risk of dangerous flooding in low-lying communities nearby.

Aquafornia news CBS - Sacramento

New multi-million dollar flood control project being tested in Sacramento region

A new multi-million dollar flood control project is about to be put to the test along the Sacramento River. Water is now starting to spill into what had been tomato and wheat fields in Yolo County. Now, the land is part of a seven-mile-long expansion of the Yolo Bypass between Interstate 5 to the north and West Sacramento to the south. It’s an area that is designed to flood when water levels rise. “Water comes from the Sacramento River down through the Yolo Bypass and out into the delta,” said David Pesavento, a supervising engineer with the California Department of Water Resources. Pesavento said this project, in the lower Elkhorn Basin, helps protect more than 780,000 people living downstream. “This project gives more space for that water to spread out and lowers the risk for the Greater Sacramento area,” he added.

Aquafornia news CBS Sacramento

Trees along American River are on the chopping block for flood control

A project by the U.S. Army Corps of Engineers (USACE) to mitigate flood risk along the American River is receiving pushback from a community group called American River Trees. “We have a rough count of 500 trees that are probably going to be eliminated,” said William Avery, biologist and professor with American River Trees. Community members are coming together to call on the Army Corps of Engineers to rethink their approach to flood control. “Instead of obliterating it and filling it with rock trenches, we want a focused approach where they fix known erosion spots locally with small equipment and not all this junk with trucks coming through,” Avery said. The American River Levee Project will add 11 miles of protection for lower levees. The USACE said in a statement that “several levee sections along the American River were identified as being susceptible to significant erosion from the higher, longer releases from Folsom Dam. The proposed bank protection work will armor the riverbank to reduce and prevent erosion which, if left unaddressed, could result in levee failure.”

Related article: 

Aquafornia news Mercury News

Pajaro, Watsonville flood victims file lawsuit against multiple agencies

More than 500 residents and business owners have filed a lawsuit against Monterey and Santa Cruz counties, as well as various other agencies and municipalities, alleging that all accused parties could have done more to prevent the massive floods that occurred in Watsonville and Pajaro between Dec. 31, 2022, and March 11. The lawsuit was filed in December and names the counties of Monterey and Santa Cruz, city of Watsonville, California Department of Transportation, Monterey County Water Resources Agency, Santa Cruz County Flood Control and Water Conservation District and Pajaro Regional Flood Management Agency. The suit covers the early months of 2023, between New Year’s Eve when a surge in rainfall at Corralitos Creek caused water to spill out into several neighborhoods in Watsonville and trapped residents in their homes, to March 11, when a breach at the Pajaro River levee resulted in flooding of the community of Pajaro and damage to several homes, businesses and agricultural fields.

Aquafornia news The Pajaronian

Watsonville, Pajaro flood victims file lawsuit

The people affected by the storms and floods that occurred between Dec. 31, 2022 and March 11, 2023 have filed two lawsuits against the counties of Monterey and Santa Cruz, as well as the flood management agencies in those counties, along with the City of Watsonville and the California Department of Transportation, alleging they did not take the proper measures to stop the damages caused by those disasters. The lawsuits allege that the defendants allowed the flood control systems of the lower Pajaro River watershed to remain in a “state of complete disrepair,” even after 10 flood events that occurred throughout the decades since the levee system was built in 1949. More than 500 plaintiffs are named in the lawsuits, from both Santa Cruz and Monterey counties. 

California Spent Decades Trying to Keep Central Valley Floods at Bay. Now It Looks to Welcome Them Back
WESTERN WATER IN-DEPTH: Floodplain restoration gets a policy and funding boost as interest grows in projects that bring multiple benefits to respond to climate change impacts

Land and waterway managers labored hard over the course of a century to control California’s unruly rivers by building dams and levees to slow and contain their water. Now, farmers, environmentalists and agencies are undoing some of that work as part of an accelerating campaign to restore the state’s major floodplains.

Tour Nick Gray Jenn Bowles Layperson's Guide to the Delta

Bay-Delta Tour 2021
A Virtual Journey - September 9

This tour guided participants on a virtual journey deep into California’s most crucial water and ecological resource – the Sacramento-San Joaquin Delta. The 720,000-acre network of islands and canals support the state’s two major water systems – the State Water Project and the Central Valley Project. The Delta and the connecting San Francisco Bay form the largest freshwater tidal estuary of its kind on the West coast.

Western Water California Water Map Gary Pitzer

Can a New Approach to Managing California Reservoirs Save Water and Still Protect Against Floods?
WESTERN WATER NOTEBOOK: Pilot Projects Testing Viability of Using Improved Forecasting to Guide Reservoir Operations

Bullards Bar Dam spills water during 2017 atmospheric river storms.Many of California’s watersheds are notoriously flashy – swerving from below-average flows to jarring flood conditions in quick order. The state needs all the water it can get from storms, but current flood management guidelines are strict and unyielding, requiring reservoirs to dump water each winter to make space for flood flows that may not come.

However, new tools and operating methods are emerging that could lead the way to a redefined system that improves both water supply and flood protection capabilities.

Western Water California Water Map Gary Pitzer

When Water Worries Often Pit Farms vs. Fish, a Sacramento Valley Farm Is Trying To Address The Needs Of Both
WESTERN WATER SPOTLIGHT: River Garden Farms is piloting projects that could add habitat and food to aid Sacramento River salmon

Roger Cornwell, general manager of River Garden Farms, with an example of a refuge like the ones that were lowered into the Sacramento River at Redding to shelter juvenile salmon.  Farmers in the Central Valley are broiling about California’s plan to increase flows in the Sacramento and San Joaquin river systems to help struggling salmon runs avoid extinction. But in one corner of the fertile breadbasket, River Garden Farms is taking part in some extraordinary efforts to provide the embattled fish with refuge from predators and enough food to eat.

And while there is no direct benefit to one farm’s voluntary actions, the belief is what’s good for the fish is good for the farmers.

Western Water Layperson's Guide to the Delta

ON THE ROAD: Park Near Historic Levee Rupture Offers Glimpse of Old Sacramento-San Joaquin Delta
Big Break Regional Shoreline will be a stop on Bay-Delta Tour May 16-18

Visitors explore a large, three-dimensional map of the Sacramento-San Joaquin Delta at Big Break Regional Shoreline in Oakley. Along the banks of the Sacramento-San Joaquin Delta in Oakley, about 50 miles southwest of Sacramento, is a park that harkens back to the days when the Delta lured Native Americans, Spanish explorers, French fur trappers, and later farmers to its abundant wildlife and rich soil.

That historical Delta was an enormous marsh linked to the two freshwater rivers entering from the north and south, and tidal flows coming from the San Francisco Bay. After the Gold Rush, settlers began building levees and farms, changing the landscape and altering the habitat.


Delta Warning

15-minute DVD that graphically portrays the potential disaster should a major earthquake hit the Sacramento-San Joaquin Delta. “Delta Warning” depicts what would happen in the event of an earthquake registering 6.5 on the Richter scale: 30 levee breaks, 16 flooded islands and a 300 billion gallon intrusion of salt water from the Bay – the “big gulp” – which would shut down the State Water Project and Central Valley Project pumping plants.


Layperson’s Guide to the State Water Project
Updated 2013

The 24-page Layperson’s Guide to the State Water Project provides an overview of the California-funded and constructed State Water Project.


Layperson’s Guide to Flood Management
Updated 2009

The 24-page Layperson’s Guide to Flood Management explains the physical flood control system, including levees; discusses previous flood events (including the 1997 flooding); explores issues of floodplain management and development; provides an overview of flood forecasting; and outlines ongoing flood control projects. 

Publication Sacramento-San Joaquin Delta Map

Layperson’s Guide to the Delta
Updated 2020

The 24-page Layperson’s Guide to the Delta explores the competing uses and demands on California’s Sacramento-San Joaquin Delta. Included in the guide are sections on the history of the Delta, its role in the state’s water system, and its many complex issues with sections on water quality, levees, salinity and agricultural drainage, fish and wildlife, and water distribution.

Maps & Posters California Water Bundle

California Water Map
Updated December 2016

A new look for our most popular product! And it’s the perfect gift for the water wonk in your life.

Our 24×36 inch California Water Map is widely known for being the definitive poster that shows the integral role water plays in the state. On this updated version, it is easier to see California’s natural waterways and man-made reservoirs and aqueducts – including federally, state and locally funded projects – the wild and scenic rivers system, and natural lakes. The map features beautiful photos of California’s natural environment, rivers, water projects, wildlife, and urban and agricultural uses and the text focuses on key issues: water supply, water use, water projects, the Delta, wild and scenic rivers and the Colorado River.

Floodplains in California

With the dual threats of obsolete levees and anticipated rising sea levels, floodplains—low areas adjacent to waterways that flood during wet years—are increasingly at the forefront of many public policy and water issues in California.

Adding to the challenges, many floodplains have been heavily developed and are home to major cities such as Sacramento. Large parts of California’s valleys are historic floodplains as well.

Aquapedia background

Sacramento-San Joaquin Delta Levees

Sacramento-San Joaquin Delta Levees

Roughly 1,115 miles of levees protect farms, cities, schools and people in and around the Sacramento-San Joaquin Delta, a crucial conduit for California’s overall water supply. But the Delta’s levees are vulnerable to failure due to floods, earthquakes and rising sea levels brought about by climate change. A widespread failure could imperil the state’s water supply.

Aquapedia background



California would not exist as it does today were it not for the extensive system of levees, weirs and flood bypasses that have been built through the years, particularly in the Sacramento-San Joaquin Delta.

These levees have been in place dating back to 1850, when California first joined the union.

Western Water Magazine

Meeting the Co-equal Goals? The Bay Delta Conservation Plan
May/June 2013

This issue of Western Water looks at the BDCP and the Coalition to Support Delta Projects, issues that are aimed at improving the health and safety of the Delta while solidifying California’s long-term water supply reliability.

Western Water Magazine

How Much Water Does the Delta Need?
July/August 2012

This printed issue of Western Water examines the issues associated with the State Water Board’s proposed revision of the water quality Bay-Delta Plan, most notably the question of whether additional flows are needed for the system, and how they might be provided.

Western Water Magazine

Levees and Flood Protection: A Shared Responsibility
May/June 2012

This printed issue of Western Water discusses several flood-related issues, including the proposed Central Valley Flood Protection Plan, the FEMA remapping process and the dispute between the state and the Corps regarding the levee vegetation policy.

Western Water Excerpt Gary PitzerRita Schmidt Sudman

Levees and Flood Protections: A Shared Responsibility
May/June 2012

Levees are one of those pieces of engineering that are never really appreciated until they fail. California would not exist as it does today were it not for the extensive system of levees, weirs and flood bypasses that have been built through the years.

Western Water Magazine

Finding a Vision for the Delta
March/April 2008

This printed copy of Western Water examines the Delta through the many ongoing activities focusing on it, most notably the Delta Vision process. Many hours of testimony, research, legal proceedings, public hearings and discussion have occurred and will continue as the state seeks the ultimate solution to the problems tied to the Delta.

Western Water Magazine

A Significant Challenge: Adapting Water Management to Climate Change
January/February 2008

This printed copy of Western Water examines climate change – what’s known about it, the remaining uncertainty and what steps water agencies are talking to prepare for its impact. Much of the information comes from the October 2007 California Climate Change and Water Adaptation Summit sponsored by the Water Education Foundation and DWR and the November 2007 California Water Policy Conference sponsored by Public Officials for Water and Environmental Reform.

Western Water Magazine

It Can Happen Here: Assessing California’s Flood Risk
November/December 2005

This issue of Western Water examines the extent to which California faces a disaster equal to or greater than the New Orleans floods and the steps being taken to recognize and address the shortcomings of the flood control system in the Central Valley and the Delta, which is of critical importance because of its role in providing water to 22 million people. Complicating matters are the state’s skyrocketing pace of growth coupled with an inherently difficult process of obtaining secure, long-term funds for levee repairs and continued maintenance.

Western Water Magazine

Flood Management 2004: A System in Peril
September/October 2004

This issue of Western Water analyzes northern California’s extensive flood control system – it’ history, current concerns, the Paterno decision and how experts are re-thinking the concept of flood management.