Army Corps gives Pico Rivera timeline and impacts for Whittier Narrows dam safety project

A virtual representative of the U.S. Army Corps of Engineers told the Pico Rivera City Council on March 11 that the Whittier Narrows Dam Safety Modification Project remains in procurement and that construction staging will require temporary use of federal land that includes parts of Streamland Park and the Pico Rivera Golf Course.

The presenter said the project is aimed at correcting two deficiencies: potential foundation seepage and a hydrologic risk from extreme storm events that could overtop the earthen embankment. To address those issues the Corps plans a two-year pre-construction services period followed by about five years of heavy construction under an early-contractor-involvement approach. "We are at the procurement phase," the presenter said, noting that many utilities around the dam require coordination.

The Corps representative said Sports Arena Drive, which crosses the East Embankment, will be removed as part of construction and that the Corps currently does not have authorization to replace the road. The earliest closures that would affect Streamland Park, the golf course and Sports Arena Drive are expected in early 2027, pending conditions on the ground and any license extensions. The Corps said it is working to extend existing licenses for those areas through the end of 2026 to delay closures.

The presenter also said Rosemead Boulevard will be raised in portions associated with the dam work and that traffic pattern changes, brief lane closures and temporary shifts are likely on Rosemead and Lincoln during construction. The Corps said it does not expect long-term lane reductions on Rosemead but that travel patterns will change.

The Corps has contracted HDR to help with public outreach and said it will continue community engagement through events such as farmers markets and bike rides. The presenter noted supply-chain risks and tariff concerns but said the Corps had received appropriations from Congress and did not foresee inability to use already-received funds.

Council members asked about resource impacts from recent fires, lease-back options for areas returned to local control and the geographic extent of Rosemead work; the Corps representative said the dam safety team remains largely intact despite fire-response work elsewhere, lease-backs would require a standard Section 408 process and that the Rosemead work stretches roughly from north of Gallatin to the bridge near Durfee.

The update was informational; no council vote or action was taken during the briefing.