The North Haiwee Dam No. 2 (NHD2) Project in Inyo County, California, is a crucial seismic upgrade managed by the Los Angeles Department of Water and Power (LADWP). The dam is located approximately 800 feet north of the original 1913 dam in the Owens Valley. The new earthfill embankment spans roughly 1,970 feet long and 42 feet high. It is designed to prevent catastrophic failure and local flooding during a major earthquake while preserving the vital flow of the Los Angeles Aqueduct.
While preliminary groundwork including the realignment of Cactus Flats Road and a section of the aqueduct channel has been successfully finished, the main dam construction (Phase III) is currently underway under primary contractor Road and Highway Builders. However, the completion schedule has experienced notable shifts. LADWP extended the contract timeline through December 2028, pushing back the original late-2025 target.
Reasons for Timeline Extension
The extended timeline stems from unforeseen site complexities. Crews have had to navigate more than 175 designated Environmentally Sensitive Areas (ESAs), dynamic state species protections (such as regulatory candidate status for Western Joshua trees), and extensive cultural resource mitigation. Because the area holds significant tribal and prehistoric heritage, archeological monitoring, testing, and data recovery efforts coordinated alongside local Native American tribes and the Bureau of Land Management have slowed physical earthmoving but remain vital to compliant execution.
Despite these logistical and environmental extensions, the project’s financial authorization remains capped under its updated $185.5 million budget limit. As foundation work involving thousands of deep-soil cement columns continues, the project remains on track to secure long-term water reliability for millions of Southern California residents.
Similar Projects
Much like the North Haiwee Dam No. 2 project, Santa Clara Valley Water’s multi-billion-dollar Anderson Dam Seismic Retrofit Project in Northern California represents a high-priority effort to modernize aging water infrastructure against catastrophic earthquake risks. Both critical undertakings reflect a broader, statewide push by California water agencies to replace legacy 20th-century dams with modern embankments and upgraded spillways, ensuring downstream flood safety while protecting vital drinking water supplies.
August 14, 2021
Sterling Construction Company, Inc has announced that its subsidiary, Road and Highway Builders has been awarded a US$135 million heavy civil contract by the City of Los Angeles for the construction of the North Haiwee Dam No 2 in Inyo County, California. The project, expected to begin in May, consists of mining and processing one million cubic yards of material for the multiple zoned embankment dam. Since no bedrock is present at the site, Sterling will drill more than 13,000 individual cement, deep-soil shafts for the dam footing. Each individual shaft is from 40 to 60 feet in length and 5 feet in diameter. The project will also involve the rerouting of the Los Angeles Aqueduct, which supplies clean drinking water to the city of Los Angeles, to allow for the appropriate tie-ins for the dam construction. The project will take approximately four and a half years to complete.
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Significance of the Project
The Project is to improve the seismic reliability of the North Haiwee Reservoir through the construction of a new dam, North Haiwee Dam No. 2 (NHD2), in order to maintain the function of an essential water conveyance infrastructure for the City of LA, as well as to protect local populations from a hazardous flooding event.
“We are extremely pleased to have been selected by the City of Los Angeles to construct NHD2,” stated Sterling’s CEO, Joe Cutillo. “The purpose of this new dam is to improve the seismic reliability of the North Haiwee Reservoir and maintain the function of an essential water conveyance for the city of Los Angeles as well as protect the local populations from the possible hazardous flooding event. This project is an excellent example of how we are executing our strategy to diversify our mix of Heavy Civil work towards higher-margin opportunities by leveraging our broad range of construction capabilities and expertise.”
Project Factsheet
Project Name: North Haiwee Dam No. 2 Construction Project
Owner and Lead Agency: Los Angeles Department of Water and Power (LADWP)
Cooperating Federal Agency: U.S. Bureau of Land Management (BLM)
Location: Owens Valley, Inyo County, California
Primary Objective: Enhance seismic reliability of the North Haiwee Reservoir and protect downstream communities against catastrophic flooding and water supply interruption in the event of a major earthquake along local fault lines.
Technical Specifications and Engineering
Dam Type: Zoned earthfill embankment dam
Dimensions:
Length: 1,970 feet
Height: 42 feet
Crest Width: 30 feet
Earthwork Volume: Approx. 1 million cubic yards of processed material
Relative Position: Built approximately 800 feet north of the original 1913 North Haiwee Dam.
Foundation Engineering: Ground stabilization utilizing Deep Soil Mixing (DSM), drilling over 13,000 individual cement-stabilized shafts (40–60 ft deep, 5 ft diameter) to prevent liquefaction without bedrock anchor.
Project Scope and Execution Phases
Phase I-Roadway Realignment (Completed Dec 2022):
Realigned 4,400 feet of Cactus Flats Road.
Constructed turn-lane improvements on US-395 Highway.
Phase II- Channel Realignment (Completed Oct 2024):
Realigned 1,950 feet of the Los Angeles Aqueduct channel to accommodate dam footprint and bypass flows.
Phase III- Main Dam Construction (In Progress):
Construction of the new earthfill embankment dam, diversion channel, and crest notch tie-ins.
Timeline and Major Milestones
Final EIR / NEPA Approval: Completed- July 2018 (EIR) / Sept 2019 (NEPA)
Contract Award / Start: Completed- Jan 20, 2021
Phase I (Roads): Completed- Dec 16, 2022
Phase II (Aqueduct Reroute): Completed- Oct 29, 2024
Phase III (Main Embankment): In Progress- Active Construction
Anticipated End of Construction: Scheduled- 2028
Project Team
Primary Construction Contractor: Road and Highway Builders LLC (subsidiary of Sterling Infrastructure)
Design & Engineering Support: AECOM Technical Services
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