ASCE Los Angeles Section

Longview Avenue and Merced Street, Pismo Beach

The Pismo Heights Water System was a gravity system with a small steel reservoir with a capacity of 100,000 gal, referred to as H3 located at the top of Pismo Heights and a larger concrete reservoir with a capacity of 220,000 gal, referred to as H2, located about half way down the hill. Water was pumped from the Bello Reservoir to H2, and then from H2 up the hill to H3. This system provided adequate water supplies, but neither adequate flows nor pressures for firefighting purposes.

With this project the City constructed a new concrete reservoir directly adjacent to the existing H2 reservoir and matching the H2 reservoir in capacity, doubling the water storage at this location. The two reservoirs are hydraulically connected; however valves were installed to allow isolation of either reservoir. A new booster station was constructed with a total of six pumps, four for domestic use, and two dedicated for fire flows. The H3 tank was decommissioned, and about a mile of new 12” water main was installed to provide increased flows from the newly configured water system.

In summary, in addition to increasing storage by 120,000 gal, this project increased pressure and flows to provide adequate fire protection by eliminating the gravity based system and replacing it with a pressure system. Total project cost was approximately $3.6 million.

The City of Pismo Beach neighborhood known as the Heights has an elevation span of over 530 feet with one access road serving the entire hillside of homes. The hillside is broken into three distinct water distribution zones, all served by a single water main in Longview Avenue. The Pismo Heights Water System Reconstruction Project tackled a top priority recommended by the City’s Water Master Plan. The project included upgrading the primary water mains in Longview Avenue and Merced Street, the construction of a new booster station and water reservoir to provide adequate water volume, pressure, and additional water storage for domestic and emergency needs next to the existing Heights 2 Tank site. Combining these improvements into one construction project allowed for a more efficient transition to the new water system and reduced the impacts to residents during construction.

The Heights 2 Tank Site was planned in the 1950’s to have an additional tank mirroring the existing tank; however, the planners at the time could not have anticipated the construction of a two-story home adjacent to the property. Constructing the new tank in between the existing tank and the two-story home, while protecting both from sustaining damage while driving in the shoring and excavating out over 25 feet of soil took finesse, collaboration, and solid engineering on both the design team and the contractor. The design for the facility increased storage and the booster station increased pressures and fire flow capabilities through the entire Heights.

Through innovative design and coordination with the contractor and the City, this project also fixed an important constraint to the project site. The old site had limited operator access to attend to the existing tank and booster station. The new site layout provides for two full parking stalls for operators.

The project site was already disturbed with no endangered species or flowers. The City completed their CEQA requirements and issued a Negative Declaration. It was the City’s desire to provide a project site that enhanced the beauty of the neighborhood and did not impact the view shed of the hillside. As part of the project, all new low water use landscaping was provided and the overhead utility lines that crossed the south side of the property were removed.

With the narrow roads, small working site, tight working conditions and the public driving and walking in and around the property, safety on the job site was a high priority. Another challenge during construction was maintaining postal service, trash pick-up and emergency access for the duration of the project. 

Innovative construction staging and strategic phasing were hallmarks of this project. The complexity of eliminating old, creating new and extending pressure zones was a challenge. All of which was coordinated and accomplished while continuing to maintain water service to all the homes. The project was a huge success; with the Heights Distribution Zone now meeting all pressure and fire flow requirements.

Since the project impacted the entire hillside community for over a year, public outreach and communication was a high priority. The City wrote a community relations plan, held two town hall meetings, walked the community talking to neighbors and passed out door hangers to ensure the community was well informed about the progress of the project and to ensure that their concerns were heard. The City kept weekly logs of any complaints from the residents and responded quickly to the community.

Project was nominated and selected for the APWA Project of the Year - Environment Projects $2-5 Million.

Innovative construction staging and strategic phasing were hallmarks of this endeavor. The complexity of eliminating old, creating new and extending pressure zones was a challenge. All coordinated and accomplished while continuing to maintain water service to all of the homes.

The contractor had to understand how the complex water distribution system operated, collaborate with Wallace Group and the City and provide detailed sequencing operations to ensure that no customers were without water for more than a few hours.

All in all, the project was a huge success. The Heights Distribution Zone now meets all pressure and fire flow requirements.

The Project included upgrading the primary water mains in Longview Avenue and Merced Street, and the construction of a new booster station and water reservoir to provide adequate water volume, pressure, and additional water storage next to the existing water tank on the corner of Longview Avenue and Merced Street.

The City of Pismo Beach neighborhood known as the Heights has an elevation span of over 530 feet with one access road serving the entire hillside of homes. The hillside is broken into three distinct water distribution zones, all served by a single water main in Longview Avenue. The Pismo Heights Water System Reconstruction Project tackled a top priority as recommended by the City’s Water Master Plan. The project included upgrading the primary water mains in Longview Avenue and Merced Street, and the construction of a new booster station and water reservoir to provide adequate water volume, pressure, and additional water storage for domestic and emergency needs next to the existing water tank on the corner of Longview Avenue and Merced Street. Combining these improvements into one construction project allowed for a more efficient transition to the new water system and reduced the impacts to residents during construction.

The City faced the challenges of a confined tank site, existing narrow roadways and limited access in the Heights area, while maintaining the previous water system as the new system was under construction. The project was fairly challenging to construct due to limited staging and storage areas and at times excavating through rock, all while maintaining postal service, trash pick-up and emergency access during the construction. This was a highly visible project and affected many residents in the Heights for over one year.