Change order approved for Rainbow's Lift Station No. 1

A change order for the design and replacement of the Rainbow Municipal Water District’s Lift Station No. 1 was approved by the Rainbow board.

The 5-0 board vote, June 26, changes the design of the lift station while increasing the total design contract amount from $1,146,854 to $1,439,965.

“These design changes will produce a product that’s going to be more cost-effective,” Rainbow general manager Tom Kennedy said.

The current Lift Station No. 1 is off Old River Road and delivers sewage effluent to Oceanside, which has an ocean outfall. The Smith and Loveless package lift station has three five-horsepower wet well-dry well pumps and a 750-gallon working volume wet well. The lift station was built in 1974, and the pumps were replaced in 1994.

Additional development is expected to increase the lift station’s duties. The lift station’s current firm capacity is 1,250 gallons per minute, and the ultimate required capacity is more than 2,600 gallons per minute. During wet weather flows the lift station pumps an average of 1,400 gallons per minute by running pumps up to 13 times an hour.

Rainbow also approved a relocation and reimbursement agreement with the California Department of Transportation regarding the state Route 76 widening. Rainbow had prior easement rights for its water lines so Caltrans was responsible for the entire cost of that system’s relocation, but the Caltrans easement rights preceded the district’s sewer line rights so Rainbow was required to reimburse Caltrans for that relocation work.

The reimbursement agreement also covered increasing the diameter of the sewer line from 12 to 18 inches, allowing both the relocation and the resizing for increased capacity to be performed by a single contractor.

In addition to insufficient wet well volume and pumps not capable of meeting wet weather flow once anticipated development in the near future is complete, the lift station is also in need of structural, mechanical and electrical repair.

In March 2014, Rainbow’s board authorized a $616,346 professional service contracts with Kennedy/Jenks Consultants, which is not affiliated with Tom Kennedy, to provide environmental permitting, design and construction oversight services for the replacement of Lift Station No. 1.

Kennedy/Jenks submitted a pre-design report which summarized the required improvements. The current infrastructure crosses the San Luis Rey River by the Camino Del Rey bridge and the wastewater line goes underneath the river.

The report noted that upsizing the existing sewer siphon for the predicted ultimate flows would require a new siphon to be horizontally drilled under the San Luis Rey River with a depth of approximately 80 feet in order to avoid bedrock.

Cultural grinding stones adjacent to the existing siphon also create the risk that environmental constraints will prevent a replacement siphon. A new lift station on the north side of the river will avoid the need for a deep siphon, and several potential locations were evaluated.

Land on Thoroughbred Lane adjacent to the Bonsall Village Center was listed for sale, so Rainbow staff negotiated with Lashanko Family 2001 Trust which owned the land. In February 2017, Rainbow’s board approved the purchase of the 1.36-acre site for the May 2016 appraised value of $740,000.

Rainbow’s $9,715,000 estimated cost for the new lift station also included $4,345,000 for the site improvements, $370,000 for a gravity sewer, $2,690,000 for a gravity sewer on Old River Road between Lift Station No. 1 and Lift Station No. 2, $1,110,000 for a force main over the Camino Del Rey Bridge to Old River Road and $460,000 for design and staff time.

The initial design was re-evaluated, and a determination was made that upsizing a stretch of sewer main along SR-76 and placing an equalization basin upstream of the existing siphon could level out the flows through the siphon to meet existing capacity requirements to Lift Station No. 1.

Moving that flow equalization upstream could allow the new Schoolhouse Lift Station to replace Lift Station No. 1 without upsizing the line to the Old River Lift Station.

The Schoolhouse Lift Station lot is at Old River Road and Calle de Las Estrellas; the agreement for the Rainbow Municipal Water District to provide sewer service to the Golf Green Estates development included the Rainbow district obtaining one of the lots for a sewer lift station. The equalization basin will be constructed near Thoroughbred Lane and SR-76.

The alternative design will allow Rainbow to complete projects needed to meet existing capacity requirements while postponing the building of projects to meet future demands until funds are available.

The projects will be funded by capacity fees which are charged to developers to cover the new development’s share of existing infrastructure, so the delay in the more comprehensive capacity enhancement allows the projects filling immediate needs to be built without using general funds paid as part of sewer rates.