LOS ANGELES — During a recent visit to Southern California, the U.S. Army Corps of Engineers South Pacific Division commander celebrated the completion of one of the Los Angeles District’s flood-risk management projects in Corona, California.
In addition to speaking at a ribbon-cutting ceremony to mark the completion of the BNSF Bridge Pier Protection Project, Brig. Gen. Paul Owen toured four other projects in the LA District’s footprint May 26 to 27, including the LA River Ecosystem Restoration Project, in collaboration with the City of Los Angeles; Whittier Narrows Dam in Montebello; the Santa Ana River Mainstem project, which includes Prado Dam, in Corona; and Santiago Creek in Orange County. All projects are being completed by the Corps’ LA District, in coordination with local, state and federal partners.
Owen was accompanied by LA District Commander Col. Julie Balten and LA District Deputy Engineer David Van Dorpe.
“This was a great trip for me to work with and learn more about what the Los Angeles District is doing on several projects,” Owen said. “We went everywhere – from Prado [Dam] to Whittier [Narrows Dam] to Santiago Creek to the BNSF Bridge Pier Protection Project.”
The whirlwind of visits saw the senior leaders driving long distances May 26 through heavily congested freeways under a sunny Southern California sky. Before heading to his first project site visit at Whittier Narrows Dam, Owen received an update about the Prado Basin Ecosystem Restoration Project from Balten and Paul Underwood, Santa Ana River Mainstem Mega Project Branch chief, at the LA District’s headquarters building in downtown Los Angeles. After leaving downtown, Owen and LA District senior leaders visited the Corps’ Base Yard in South El Monte to receive a briefing about the Whittier Narrows Dam Safety Modification project from Justin Gay, Mega Projects Division chief, and others working on the project, before heading to the dam.
WHITTIER NARROWS DAM SAFETY MODIFICATION PROJECT
Whittier Narrows Dam was constructed in 1957 by the U.S. Army Corps of Engineers as a flood-risk management project and is located 11 miles east of downtown Los Angeles. The dam protects more than 1.2 million people.
Following Hurricane Katrina, the Corps dramatically overhauled its process for prioritizing dam and levee evaluations and modifications to better account for potential impacts to the population protected by the structures. The Whittier Narrows Dam Safety Modification Study was subsequently initiated to evaluate the risk to the population, which extends from Pico Rivera to Long Beach.
In May 2016, the Corps placed Whittier Narrows Dam in the agency’s highest risk category, “very high urgency,” when it became clear three potential failure modes threatened the downstream population. The three failure modes are premature opening of the San Gabriel River Spillway gates, erosion resulting from water piping through the foundation of the earthen dam and overtopping during an extreme flood. While the first would result in downstream flooding as the levees were overtopped, the latter two could result in a catastrophic failure of the dam.
In 2019, the Corps awarded a $5-million contract to Metro Builders of California to complete construction on the spillway gates, which were completed in December 2020.
The Whittier Narrows Dam Safety Modification Study was completed in June 2019 and went into the design phase in October 2019. Utility contracts are anticipated to be awarded in late summer 2021 and construction contracts for the dam modification are anticipated to be awarded in 2022.
The modifications will prevent the earthen dam from breach and include placing concrete on the crest and downstream slope of the embankment and improving the seepage control system with features like trench drains and graded filter/drainage blankets.
LA RIVER ECOSYSTEM RESTORATION PROJECT
On May 27, Owen and others with the LA District took in a view overlooking the LA River from Elysium Park to discuss the Los Angeles Ecosystem Restoration Project, before meeting with LA city officials in Taylor Yard, next to the river. Balten, along with Priyanka Wadhawan, LA District project manager, and Erica Kemp-Weitzman, section chief of the LA District’s Hydrology and GIS section, updated the general about the project.
The LA River Ecosystem Restoration Project is a joint effort with the City of Los Angeles to restore about 11 miles of the river, from Griffith Park to downtown Los Angeles, while also maintaining existing levels of flood-risk management. Restoration measures include the creation and reestablishment of historic riparian strand and freshwater marsh habitat to support increased populations of wildlife and enhance habitat connectivity within the project area, as well as to provide opportunities for connectivity to ecological zones, such as the Santa Monica Mountains, Verdugo Hills, Elysian Hills and San Gabriel Mountains, among others.
It is one of three public-private partnerships, or P3, pilot projects with the U.S. Army Corps of Engineers – an alternative method to develop approaches to deliver projects faster and with greater flexibility. The concept of the P3 project aims at using a split-delivery approach, in which the city takes on more responsibilities that will accelerate project completion, enhance efficiency and reduce unnecessary redundancies in project delivery to complete a majority of the project benefits by 2028, lower total project costs and maximize the federal return on investment.
Public-private partnerships are a tool that can accelerate delivery by providing significant upfront funding, and by leveraging appropriations, while optimizing local participation and promoting risk sharing in project delivery.
SANTA ANA RIVER MAINSTEM PROJECT
The entourage then traveled to the City of Corona, where Owen spoke at a ribbon-cutting to celebrate the completion of the BNSF Bridge Pier Protection Project along the Santa Ana River in Corona, California. The project was a collaborated effort with the Corps’ LA District and the tri-counties of Riverside, Orange and San Bernardino.
The purpose of the project is to minimize risk to the railroad bridge in flood conditions and during increased water releases from Prado Dam resulting from periods of heavy rainfall.
The completion of the more than $100-million bridge pier protection feature is part of the $2.8-billion Santa Ana River Mainstem Project, which is a fully integrated flood-risk management system for the Riverside, Orange and San Bernardino counties, several major freeways, the rail system itself, and an array of businesses and infrastructure in the basin.
No protection features were in place at the bridge piers or along the riverbank at the bridge prior to the project; the BNSF railroad bridge is now fully protected from water releases up to 30,000 cubic feet per second downstream of Prado Dam.
Following the ceremony, the general toured the entire Santa Ana River Mainstem Project, as well as Santiago Creek, another site managed by the Corps in Orange County. There, the general was briefed by Balten and Damien Lariviere, LA District project manager, about the creek and the entire overall project.
Before departing Los Angeles to return to San Francisco, Owen took a moment to recognize Lariviere and another Corps employee with coins for their dedication to duty.
“This was a fully packed two days of activity,” Owen said. “I got a really good perspective of all of the complexities that the Los Angeles District is working on.”