California's Water: Protecting Against Floods

Local water and flood control agencies know that the time to prepare for a flood is not when it begins to rain. Comprehensive planning and foresight are needed to invest in programs and infrastructure that can prevent flooding or greatly minimize flood damage.

This segment of “California’s Water” focuses on floods and what local agencies are doing to protect people and property. Viewers will get a look at three examples of modern flood control efforts and learn how some agencies are improving flood protection for their communities while also enhancing habitat for wildlife.

Background on the Issue

Flooding has always been an unfortunate fact of life in California. The Central Valley, for example, used to become a vast inland sea each spring as snowmelt cascaded out of the Sierra into the Sacramento and San Joaquin River systems.

Today, modern flood control facilities and flood management activities help protect people and property from the destructive power of floods.

Controlling floods is an important responsibility for federal, state and local agencies, and they take that responsibility seriously. Many local agencies today are taking that concept one step further with projects that integrate flood management with environmental enhancements and water quality improvements. These so-called “multi-objective” programs allow agencies to achieve multiple goals and leverage funding from a variety of sources to meet the need for better flood protection and more efficient water management.

Some projects combine floodwater management with groundwater recharge. Others integrate watershed restoration and open space preservation with improved flood control. The result is a win-win for people and the environment.

Projects Around the State

Sacramento is one of the most vulnerable areas in the state when it comes to flood risk. Local, state and federal agencies have been working together for decades to improve flood protection in the wake of record floods that nearly inundated Sacramento in 1986 and again in 1997. The short-term goal is to achieve 100-year flood protection, while the longer-term goal is to achieve better than 200-year flood protection. A 100-year level of protection means the city would be protected from a flood with a one-in-100 chance of occurring in any given year.

Today, flood agencies are using innovative erosion control methods that improve flood control but also enhance the environment.

The Santa Clara Valley is another area that has long dealt with the threat of seasonal flooding from the Guadalupe River. Thanks to the Guadalupe River Park and Flood Protection Project, local agencies have dramatically improved flood protection for downtown San Jose and other neighborhoods and businesses while protecting habitat and greatly expanding the Guadalupe River Park with new trails, plazas and open space.

Over the past two decades, Santa Clara Valley Water District has invested $1.2 billion in flood protection improvements, including major construction projects, channel maintenance and other activities. The Guadalupe project has been a partnership among various public and private agencies. Some of the features of the project include: an underground bypass system to divert fast-moving floodwater away from the river, channel widening, bridge replacement, trails on both sides of the river, and additional riparian habitat. Flood protection features were completed in 2004, and recreational elements were finished in 2005.

In Southern California, Seven Oaks Dam was constructed as part of the Santa Ana River Mainstem Project, which provides flood protection to more than 3 million people in Orange, Riverside and San Bernardino counties. It is an example of successful planning and partnership among local agencies and the federal government.

The dam, built by the U.S. Army Corps of Engineers and completed in 1999, is 550 feet high and more than 2,200 feet wide at its base. The reservoir created by the dam has a capacity of 146,000 acre-feet of water. The dam is operated and maintained by the Orange County Flood Control District, the San Bernardino County Flood Control District and Riverside County Flood Control and Water Conservation District.