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Levee improvements to reduce flood risk are coming your way!

The U.S. Army Corps of Engineers and our partners, the California Central Valley Flood Protection Board (assisted by the California Department of Water Resources), and the Sacramento Area Flood Control Agency, will soon be constructing levee improvements in the Lower Natomas Basin. This work is part of the American Rivers Common Features – Natomas Basin project that was authorized by Congress in 2014. See the map above for the locations where work will occur.

While this flood risk reduction work will ultimately make Natomas safer, it will also temporarily impact area roadways. Sections of Garden Highway, mostly east of Interstate 5, will be closed for up to six months during spring and summer 2019. We’ll have more information about this in the coming months. Shorter road closures will also occur at West El Camino Avenue, San Juan Road, Del Paso Road, and perhaps other locations, at some point during 2019 and 2020.

Road closures, particularly of Garden Highway, will cause increased traffic and likely longer commutes. Look for the road signs – we’ll use them to provide information about upcoming construction in the immediate area. Detours will be provided during the closures. You may want to begin planning alternate travel routes now.

Sign up for e-mail updates by contacting our Public Affairs Office at spk-pao@usace.army.mil or (916) 557-5100. You can also get updates by periodically checking this web page at www.spk.usace.army.mil/natomas or by following us on social media at www.facebook.com/sacramentodistrict and www.twitter.com/usacesacramento.

We understand this will be an inconvenience to those who live and work in the Natomas Basin, and for that we apologize in advance. The levee improvements are necessary to reduce the chance of catastrophic flooding in your community. We ask for your patience while we help make Natomas an even better place to live.

Project Description (By Reach)

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Natomas Basin

Sacramento's Natomas Basin is one of the most at-risk areas in the nation for catastrophic flooding. Improvements to Natomas levees were originally authorized as part of the Corps' American River Common Features project in 1996, intended to improve the system of levees throughout the greater Sacramento area. Since then, the scope and cost of Natomas levee improvements have increased after high water events in 1997 and 2006 showed serious underseepage in the basin. In 2010, a post-authorization change report was completed detailing the Corps' recommended plan for improving Natomas levees. The project to improve the 42-mile ring of levees surrounding the basin was authorized in 2014. The Sacramento Area Flood Control Agency completed the first 18 miles of levee improvements, and the Corps began construction on the remaining 24 miles in 2018.

Reach A

Sacramento River east levee from the Interstate Highway 5 crossing of the American River upstream (west and north) to San Juan Road. The length of this reach is approximately 3.8 miles. The general improvements include widening the existing levee a minimum of 15 feet through construction of an adjacent levee, and installation of approximately 3.4 miles of seepage cutoff wall with a maximum depth of approximately 103.5 feet, and flattening the landside levee slope. The NPAC EIS also evaluated the use of a seepage berm in certain areas of this reach.

Reach B

Sacramento River east levee from San Juan Road upstream (north) to Elverta Road. The length of this reach is approximately 9.5 miles. The general improvements include widening the existing levee by construction of an adjacent levee, installation of approximately 4.3 miles of a seepage cutoff wall that ranges in depth between approximately 40 and 115 feet, and installation of approximately 5.6 miles of seepage berms that range in width from approximately 80 to 300 ft, and flattening the landside levee slope.

Reach C

Sacramento River east levee from Elverta Road upstream (north) to Sankey Road at the west end of the south levee of the Natomas Cross Canal (NCC). The length of this reach is approximately 5 miles. The general improvements include widening the existing levee by construction of an adjacent levee, installation of approximately 4.6 miles of seepage cutoff wall that ranges in depth between approximately 19 and 65 feet, and installation of approximately 2.7 miles of seepage berms that range in width from between approximately 100 to 500 ft, and flattening the landside levee slope.

Reach D

Natomas Cross Canal south levee from Sankey Road upstream (northeast) to Howsley Road at the PGCC. The length of this reach is approximately 5.5 miles. The general improvements include widening the existing levee by fix in-place construction, and installation of a seepage cutoff wall that ranges in depth between approximately 60 and 75 feet, and flattening the landside levee slope.

Reach E

Pleasant Grove Creek Canal (PGCC) west levee from Howsley Road upstream (south) to Sankey Road. The length of this reach is approximately 3.3 miles. The general improvements include widening the existing levee by fix in-place construction, and installation of a seepage cutoff wall that ranges in depth between approximately 65 and 70 feet, and flattening the landside levee slope.

Reach F

The Natomas East Main Drainage Canal (NEMDC) west levee from Sankey Road downstream (south) to Elverta Road. The length of this reach is approximately 4.7 miles. The general improvements include widening the existing levee by fix in-place construction, installation of approximately 2.6 miles of seepage cutoff wall with a depth of approximately 53 feet, and flattening the landside levee slope.

Reach G

The NEMDC west levee from Elverta Road downstream (south) to the drainage pumping station just upstream of Dry Creek. The length of the reach is approximately 3.6 miles. The general improvements include improving the levee by fix-in-place construction, and installation of a seepage cutoff wall with a depth of approximately 40 feet, and flattening the landside levee slope.

Reach H

The NEMDC west levee from the pumping station just upstream of Dry Creek downstream (south) to Northgate Boulevard. The length of this reach is approximately 4.5 miles. The general improvements include improving the existing levee by fix-in-place construction, and installation of a seepage cutoff wall with a depth of approximately 41 feet, and flattening the landside levee slope.

Reach I

Scheduled to begin in spring 2018, construction will occur on the American River north levee from Northgate Boulevard downstream (west) to Interstate Highway 5. The length of this reach is approximately 1.8 miles. General improvements include improving the levee by fix-in-place construction, and installation of a seepage cutoff wall with a depth of approximately 37 feet, and flattening the landside levee slope.