Southwest contracted for North River Road sewer repairs

Southwest Pipeline & Trenchless Corp. was given the Rainbow Municipal Water District contract for the second phase of the North River Road Land Outfall pipeline repairs.

A 4-0 Rainbow board vote Aug. 25, with Helene Brazier abstaining, awarded Southwest the contract for the company’s bid amount of $608,968. That phase will line high-priority sections with cast in place pipe. Approximately 9,000 feet of pipe will be included in that rehabilitation.

“It’s an important project to ensure the reliability of our wastewater service,” Tom Kennedy, Rainbow general manager, said.

The North River Road Land Outfall conveys wastewater to Oceanside’s San Luis Rey Water Reclamation Facility. The sewer main was built in 1974 and is the primary line to the Oceanside Outfall. All sewage from the Interstate 15 area goes through that line.

The pipeline is nearly 3 miles in length, from just west of state Route 76 to the intersection of Stallion Drive, and 58 maintenance holes provide access to various parts of the infrastructure. The vitrified clay pipe is 15 inches in diameter, and the sewer relies on gravity for its flow.

The rainfall during weather year 2018-2019 caused wastewater flows at the Stallion and North River Road flow metering stations to exceed capacities. The increased flow is believed to be due to significant infiltration and intrusion of rainwater into the wastewater collection system.

In June 2019, Rainbow staff began an evaluation of the vitrified clay pipe which involved clearing the line and then conducting a video and photographic inspection of nearly 1 mile of pipeline and 15 maintenance holes. The video inspection revealed multiple repair needs. Another section was inspected in October 2019.

Rainbow staff began developing the logistics of repair efforts. The plans and specifications addressed broken or badly cracked sections of pipe, infiltration and intrusion, raising maintenance holes to finish grade, lining existing maintenance holes and providing cast in place pipe at the worst sections.

The March 2020 rains caused another overflow of the pipeline. Rainbow staff conducted video and photographic inspections and observed two sections which were in imminent danger of collapsing.

Kennedy declared an emergency April 17 so that repair work could commence before the next Rainbow board meeting. The April 28 board vote ratified Kennedy’s action and appropriated additional funding for the repair work. Kennedy issued a contract to SCW Contracting Corporation, which is based in the town of Rainbow, and following preparation SCW began the repair work the night of April 19.

Rainbow had planned to repair the North River Road Land Outfall over a multiyear period, but the immediate risk led to the decision to repair the entire 3-mile pipeline as soon as possible. During the emergency Hoch Consulting was retained to assist Rainbow staff in finalizing the plans and specifications.

As the inspections and research were being conducted Rainbow staff decided that Hoch was best suited to expand and expedite the plans and specifications needed for the repair work to be advertised for bid. Rainbow staff and Hoch worked together to prepare a phased construction approach which will allow the sections with the worst conditions to be addressed first and remaining phases to follow.

A 5-0 Rainbow board vote, June 23, approved a $151,180 contract with Hoch Consulting for the preparation of the bidding documents and for engineering support to the district.

The first phase will excavate and make repairs to the pipeline, replacing the vitrified clay pipe with polyvinyl chloride pipe. The July 28 Rainbow board meeting included a 5-0 vote to award the work to SCW. That phase is expected to be complete by mid-September.

Rainbow staff advertised the second phase for bid July 17 and set an Aug. 11 bid opening date. Two addendums were issued during the bidding phase, so the bid opening was rescheduled from Aug. 11 to Aug. 18 and all questions from prospective bidders were answered.

Four companies submitted proposals. Southwest Pipeline, which is based in Torrance and has a San Diego office, provided the bid with the lowest cost amount.

Phase III is the third and final phase, and Rainbow is in the process of working with Hoch Consulting to prepare the bid documents. The district’s goal is to complete all three phases before the rain season in 2021.

“It’s the most cost-effective way to ensure that it lasts another 50 years,” Kennedy said.

Joe Naiman can be reached by email at [email protected].