Rainbow MWD adds casing installation to Highway 76 work

Rainbow Municipal Water District and the California Department of Transportation have been working together to coordinate the relocation of the Rainbow water and sewer lines which must be moved to accommodate the State Route 76 widening. The collaboration will now include the installation of four 36-inch casings perpendicular to the highway which will allow for future access by the district.

4-0 Rainbow board vote May 26, with Bob Lucy absent, approved a change order which added the casings. The Caltrans contractor or subcontractor will perform the work while Rainbow will provide the funding for the additional scope of work, which has an estimated cost of $200,000.

"It's going to be a very low-cost way to get access," said Rainbow general manager Tom Kennedy.

Rainbow had a water line easement prior to the construction of the existing Highway 76 alignment, so Caltrans will cover the entire cost of relocating Rainbow's water line. Rainbow did not have prior sewer line rights and is responsible for the cost of the sewer line relocation, and the district utilized that replacement opportunity to upgrade the sewer line diameter between Sweetgrass Lane and Gird Road from 12 inches to 18 inches.

A reimbursement agreement allowed all work to be performed by a single contractor, although Rainbow will provide inspection oversight. An initial agreement was approved by the Rainbow board in November 2013 under which Rainbow would reimburse Caltrans an estimated $13,920,000 over a three-year period, but that engineer's estimate did not take into account synergies such as heavy equipment already being on the site and road work to be performed regardless of the relocation.

The bid structure for the highway widening included subtotals for approximately 350 items including labor and overhead for each item as well as materials and other expenses. Ames Construction submitted the low bid of $75.2 million, and after Caltrans reviewed the bid to ensure that Ames and its subcontractors could perform each task for the price submitted, the contract document was finalized and Ames was issued a notice to proceed on August 18, 2014.

Eight days later, the Rainbow board approved an updated agreement with Caltrans; the breakdown of separate items provided an actual cost of $2,885,964 for the sewer work not including contingency or inspection. The agreement is for the first of two Caltrans phases and does not cover a sewer line adjacent to Live Oak Creek Bridge, whose construction costs are not yet known.

Rainbow and Caltrans subsequently determined that installing the casings would facilitate future access. The casings will eliminate the need for open cut of the highway to install facilities and will also facilitate the permit process for installing facilities underneath the roadway. "While they're building it, we can get under the street, under the roadway," Kennedy said. "It's a lot cheaper to do it now than it would be later, probably five to 10 times cheaper."

The casings will be placed in locations with the greatest potential for future use. Two will be installed at Gird Road, one will be installed at Monserate Hill Road, and one will be on the east side of the aqueduct near Sage Road.

"We can get access to that low-bid process by partnering with Caltrans," Kennedy said.

Rainbow will pay the up-front costs for the casings, which could also be leased or transferred to other utilities.