Carollo given design contract for Warm Springs Sewage Lift Station replacement


In 1991, the Eastern Municipal Water District constructed the Warm Springs Lift Station, which is a regional sewage lift station serving Temecula and Murrieta. In September 2019, a limited condition assessment of the facility’s wet well noticed significant deterioration of concrete surfaces. On Wednesday, July 1, the EMWD board voted to authorize a contract with Carollo Engineers Inc. for the design of a replacement lift station.

Eastern’s board voted 3-0, with Stephen Corona and David Slawson unable to participate in the meeting, to issue a $1,377,597 contract to Carollo. The action appropriated $1,899,700, which also covers permits, an environmental consultant, third-party review and in-house labor and materials.

The September 2019 inspection led to a recommendation to perform a more detailed analysis to assess the wet well’s structural integrity. On Jan. 8, the EMWD board approved an agreement with Carollo, which is headquartered in Walnut Creek and has an office in Riverside, to perform the wet well assessment and a condition assessment of the upstream trunk sewers and to develop recommendations for repair or replacement. Carollo found that the structural integrity of the wet well was distressed but was capable of sustaining a limited load. Carollo recommended that native soil and asphalt above the wet well be removed and replaced with lighter cellular concrete to reduce stress on the structure, and that work was performed. Until a long-term solution is implemented, driving heavy vehicles over the wet well is restricted. The implementation of those two interim measures allowed for the development of long-term solutions, and Carollo provided options to rehabilitate the existing lift station and to construct a replacement station adjacent to the existing site.

EMWD staff reviewed the total cost, completed project life expectancy, construction difficulty, construction sequencing, operations risk, shallow groundwater presence and ability to maintain the project for both alternatives. Both projects had similar overall costs, but replacing the lift station would give it a longer life span than a rehabilitation and a new station would also improve site access for maintenance and allow for the site’s elevation to be raised to reduce the potential for flood damage.

On April 27, EMWD staff sent eight consultants a request for proposals for the Warm Springs Sewage Lift Station replacement preliminary and final design, and four of those firms responded by the June 2 deadline. A panel selected Carollo as the preferred firm based on the company’s ability to perform the work demonstrated, their detailed understanding of the project, the qualifications of their team, their project schedule and their successful completion of similar work for the district in the past. EMWD staff and Carollo negotiated the $1,377,597 contract amount. The full $1,899,700 will also fund the environmental compliance and advertisement for bid stages of the project. The total estimated cost for the Warm Springs Sewage Lift Station replacement including construction is $3,056,900.

The design phase will also provide sufficient information to prepare an environmental statement to comply with California Environmental Quality Act requirements.

Joe Naiman can be reached by email at