Nacimiento Pipeline Unit G Repair

In early 2023, severe storms caused major damage to the Nacimiento Water Project (NWP) Pipeline south of Atascadero. About 800 feet of the pipeline failed after floodwaters eroded the soil supporting it. This failure disrupted water service to the City of San Luis Obispo and Santa Margarita Ranch. A temporary above-ground pipeline was installed to restore service, but a long-term solution is needed. To mitigate against future damage and ensure reliable water delivery, this project proposes permanently realigning approximately 5,000 feet of the pipeline, including the damaged section, out of the floodway and 100-year floodplain. This $9.6 million project will reduce the risk of future storm impacts and help maintain consistent water service for all NWP participants: the City of Paso Robles, Templeton Community Services District, Atascadero Mutual Water Company, Santa Margarita Ranch, and the City of San Luis Obispo. It's anticipated that FEMA and Cal OES will cover 93.75 percent of total project costs.

What's Happening

The pipeline currently sits in a flood-prone area and this project moves the pipeline to a safer location to:

  • Restore water supply deliveries
  • Protect the regional water supply 
  • Reduce future emergency repair costs
Project Status: Final Design

Tree Trimming and Removal Start: Fall 2026 

Construction Start: Spring 2027

Duration: ~6–8 months total 
This page will be updated regularly with construction schedules, road impacts, and notices.


Completed Milestones

  • January 9, 2023 – Nacimiento Water Project Pipeline collapsed into the Salinas River after heavy flooding. 
  • January 9, 2023 – The Emergency Services Director issued a Proclamation of Local Emergency. 
  • January 14, 2023 – A Presidential major disaster, CA-4683-DR, was declared for the State of California on January 14, 2023, for severe winter storms, flooding, landslides, and mudslides occurring beginning December 27, 2022. 
  • January 17, 2023 – San Luis Obispo County was added to Presidential Disaster Declaration CA-4683-DR through Amendment No. 1. 
  • January 24, 2023 – The Board acting as the Board of Supervisors for the San Luis Obispo Flood Control and Water Conservation District reviewed, ratified and approved the emergency actions needed to repair the Nacimiento Water Pipeline. 
  • March 2023 – The District hired an engineering consultant to analyze Nacimiento Water Pipeline repair alternatives and design the selected alternative. 
  • August 24, 2023 – Repair Alternatives were presented to the Nacimiento Commission. The Nacimiento Commission recommended that staff proceed with delivering the proposed realignment project. 
  • November 2023 – Right of Entry Agreements obtained from impacted property owners for survey and geotechnical investigations to support the proposed realignment project. 
  • February 22, 2024 – The Nacimiento Commission recommended that the Board authorize a budget adjustment in the amount of $1,038,000 to complete design and planning for the realignment project. 
  • October 2024 – Notification was sent to Salinas Road residents regarding the proposed realignment project and planned geotechnical investigations on Salinas Road. 
  • June 2024 – The Board acting as the Board of Supervisors for the San Luis Obispo Flood Control and Water Conservation District approved the Nacimiento Water Project Fiscal Year 2024-25 Budget, which included $8,292,000 for funding final design and construction of the realignment project. 
  • June 2024 – Staff conducted site visits with permanent easement property owners. 
  • May 2025 – Environmental Impact Report amendment finalized. 
  • May 2025 – Initiated easement acquisition discussions and negotiations. 
  • May 13, 2025 – Chia Lane community meeting held. Staff met with Chia Lane residents to share proposed project plans, potential community impacts and access options.
  • June 6, 2025 – Draft Final Design completed. 
  • June 17, 2025 – Salinas Road community meeting held. Staff met with Salinas Road residents to share proposed project plans, inform residents that construction of the project will require limiting access to properties, and collect feedback in order to find ways to reduce those impacts. 
  • August 13, 2025 – Chia Lane site visit completed. Staff met with Chia Lane residents to review site conditions.
  • September 2025 to June 2026 – Easement discussions and negotiations continued.
  • July 9, 2026 – The Nacimiento Commission approved and recommended that the Board subsequently approve several settlements and agreements associated with the acquisition of easements needed for the pipeline realignment project. 

Next Milestones

  • August 2026 – The District Board will review and consider approving several settlements and agreements associated with the acquisition of easements needed for the pipeline realignment.
  • September - February 2027 – Salinas Road Tree Removal and Trimming.
  • May 2027 – Target construction start.
  • December 2027 – Target construction completion. 
  • 2027-2033 – Target environmental mitigation. 


Stay Updated

Bookmark this page for:

  • Project updates
  • Road closure notices
  • Schedule changes

Project Contacts

Nola Engelskirger, Water Utilities Division Manager
(805) 788-2100
[email protected]
Anna McKenna, Supervising Engineer
(805) 781-1521
[email protected]

FAQs

Placement of the Pipeline in Salinas Road will relocate this portion of pipeline out of the flood plain, reducing the likelihood of future failures due to flooding. The District evaluated alternative routes, but Salinas Road was ultimately chosen because it best meets the project goals and improves long term resiliency of the Nacimiento Pipeline. 

In addition, Salinas Road is an original Atascadero Colony road, over which the County of San Luis Obispo has received and accepted an offer of dedication for an easement per Board Resolution in 1993. The properties along this segment of Salinas Road are subject to this easement.

Construction will generally occur between 7 a.m. to 5 p.m. The work will include occasional heavy equipment along Salinas Road, resurfacing along Salinas Road and Chia Lane, trenching and culvert replacement along Salinas Road, horizontal drilling under the river on privately owned parcels, and tree trimming and removal within County right-of-ways. A temporary route from Chia Lane to Salinas Road will be constructed to limit traffic delays during construction. The horizontal direction drilling will occur on privately-owned parcels and will result in some noise in the area and may occur outside of standard construction working hours. Prior notice will be issued for construction activities outside of standard working hours.  
During the culvert replacement, Salinas Road will be shut down to all residents north of the culvert. Salinas Road resident access will be through a temporary road connecting Chia Lane and Salinas Road. It is estimated that the culvert work will take 2-3 weeks. After the culvert work is completed, Salinas Road residents will continue to have continuous access via the temporary road and have limited access via Salinas Road. The contractor will be required to prepare a traffic control plan for the duration of the project, which will include signage, speed limits, and flaggers if needed. 
Residents on both Salinas Road and Chia Lane will experience elevated noise levels during construction and experience traffic delays on Salinas Road. The culvert replacement will temporarily require a full closure of Salinas Road (north of the culvert). Advance notice will be provided. Chia Lane residents can expect increased traffic volume from Salinas Road residents and service providers. 
Yes, residents will have access to their properties throughout construction. While brief delays may occur, emergency access will always be available
To protect the pipeline from future root intrusion and improve construction access, several trees along Salinas Road will be trimmed, and five oaks within the County right‑of‑way, one oak on private property, and one pine on private property will be removed under easement agreements, with required mitigation and replanting. Protecting the trees in place would reduce access during construction and increase construction time. Property owners interested in mitigation trees on their property can reach out to the District.
After the project is completed, Salinas Road will be maintained by the District’s Water Utilities team as needed to ensure access to the pipeline and any appurtenances along the road. Residents can expect the District to perform annual maintenance to the road surface as needed to maintain year-round access to the pipeline facilities. In addition, seasonal vegetation maintenance will be performed at above and at-grade facilities such as valves and pull boxes. The District is also willing to work with the Salinas Road residents as a partner in road maintenance. Residents may contact us with any concerns that they have about the road condition after the project is complete.