Folsom Dam Raise

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Folsom Dam

Folsom Dam Raise Project

The U.S. Army Corps of Engineers Sacramento District is moving forward with the Folsom Dam Raise Project to help further reduce flood risk in the Greater Sacramento area. The overall project includes the following authorized components: a three-and-a-half foot raise of the Folsom Facility dikes, Mormon Island Auxiliary Dam (MIAD), Left Wing Dam (LWD), and Right Wing Dam (RWD), along with modifications to the main dam’s Tainter gates; construction of automated temperature control shutters at the main dam to benefit American River fisheries, and; habitat restoration at two sites along the lower American River - Bushy Lake Restoration Site and Woodlake Restoration Site. The overall project also included construction of the Folsom Dam Bridge, which was completed in 2009.

The Dam Raise Project has prioritized completion of the remaining flood risk reduction elements of the overall project, which include raising the existing crest elevation of Dikes 1 through 8, MIAD, LWD, and RWD by approximately 3.5 feet, plus various structural changes to Folsom Dam (primarily modifications to the Tainter gates situated near the crest of the dam). This work is expected to enhance utilization of Folsom Lake’s existing surcharge flood storage space and increase the temporary water storage space that can be used during flood events.

The Corps, in coordination with the California Central Valley Flood Protection Board and the Sacramento Area Flood Control Agency, has prepared a joint Supplemental Environmental Impact Statement/Environmental Impact Report (SEIS/EIR) for the flood risk reduction elements of the Dam Raise Project mentioned above. The draft SEIS/EIR was first released for public review in July 2016. This version of the SEIS/EIR underwent substantial revisions following the original review period. The revised draft SEIS/EIR was released for public review in June 2017. The Corps released the final SEIS-EIR in October 2017. The record of decision was signed in December 2017.

Frequently Asked Questions

How long will construction take?
The Folsom Dam Raise project is scheduled for completion in 2028. Various components of the project will be under construction at various times; these components include the Main Dam gates, Dikes 1-7, Mormon Island Auxiliary Dam, and the Left and Right Wing Dams.

Dike 8 was completed in May 2020.

Although schedules and timeframes are only an estimate, we do our best to complete projects on schedule to effectively steward congressional appropriations and minimize impacts on local communities.
How much money will this cost, and where will the funding come from?
Most of the funding for the Folsom Dam Raise project has been appropriated by Congress, including allocating $216.5 million of Supplemental funds for the project in the 2018 federal budget.

The State of California Central Valley Flood Protection Board and the Sacramento Flood Control Agency are the local sponsors of the project and have also contributed funds.

Our aim is to complete the project with existing appropriations.
What is the chance of delays to this project?
- While we do our best to adhere to projected timelines, occasionally there are unforeseen circumstances that delay a project.
- These are difficult to predict, but in these events, we make it a priority to minimize delay and communicate transparently with the affected public.
How is USACE working with other governmental entities to accomplish this mission?
Stakeholders in the Folsom Dam Raise project include the Bureau of Reclamation, the Sacramento Area Flood Control Agency, and the Central Valley Flood Protection Board.

To the maximum extent possible, we always coordinate with local, state, and federal partners to ensure a whole-of-government approach to problem solving and include stakeholders at all levels of a project.
Do you hold public meetings and comment periods for this project?
The Sacramento District holds periodic public meetings to inform communities of our projects. We will announce these meetings on our website and social media.

Public meetings are usually accompanied by a formal comment period. This is a chance for the public to make formal comments that will become part of the public record for that project. Instructions for submitting a comment will be given prior to each comment period.

Outside of a formal comment period, feedback on our projects is always welcome. You can contact the Sacramento District directly via mail, email, phone, or social media to voice any concerns.
Why is USACE raising the structures around Folsom Lake instead of dredging the lake so it can hold more water?
A feasibility study was performed for the Dam Raise project prior to its approval by Congress. The feasibility study concluded that raising the dam was the most cost-effective way to meet the project’s flood risk management goals.
I live near Folsom Lake. Why is there traffic, dust and noise on my street?
Construction always comes with impacts to local communities. We strive to mitigate these as much as possible and complete the project on schedule to minimize these impacts. The Environmental Impact Statement and Environmental Impact Report for the project documents these impacts and the measures that will be taken to mitigate them.

In our construction planning, we plan routes in and out of the construction site that strive to minimize impacts to local residents. These may include time restrictions on construction vehicles, designated routes outside of residential areas for heavy construction equipment, or other measures as necessary.

We also seek to deliver up-to-date information so residents have ample lead time to make adjustments if necessary.
Will the Folsom Dam Raise program create more floodplain in the areas around the lake, such as Folsom, Orangevale, or Granite Bay?
No. The purpose of the Folsom Dam Raise program is to reduce flood risk to the entire Sacramento area.

We are adding top seals to the Folsom Dam gates and increasing the height of the earthen structure by 3.5 feet to create an extra 42,000 acre-feet of temporary storage capacity within Folsom Lake. This extra capacity will only be used in significant flooding events, to reduce the likelihood of Folsom Dam and other downstream structures overtopping or failing.

When completed, the Folsom Dam Raise program should provide reduced flood risk for nearly 500,000 people and 125,000 structures.
What steps has the Sacramento District taken to minimize the risk of vandalism or graffiti on Folsom Dam structures?
During construction, public access in the construction areas will be limited by security measures.

Despite these efforts, we are aware that trespassing sometimes occurs.

Our design plans for the dikes around Folsom Lake include a non-stick coating intended to make graffiti removal much easier.

If you see or are aware of any trespassing on Folsom Dam sites, please contact the Sacramento District or the Bureau of Reclamation (which operates Folsom Dam) as soon as possible.

We strive to be responsive to the public’s concerns while working to minimize flood risk. We design our structures in accordance with the best available technology and engineering.
What should I do if I believe the Corps has damaged my property during this project?
If you believe your property has been damaged by Sacramento District projects, please email us at spk-pao@usace.army.mil. Upon receipt of your message, we will advise you of the next steps for filing a complaint.

We strive to be good neighbors and conduct our projects with minimal impacts.