Sukut Construction Performs Lower Elkhorn Basin Interior Drainage Contract for the Sacramento Area Flood Control Agency

By Brian Hoover, Senior Editor

The Lower Elkhorn Basin Levee Setback (LEBLS) project is part of the Central Valley Flood Protection Plan (CVFPP). It is also the first multi-benefit flood management project developed by the California Department of Water Resources (DWR) in the Yolo Bypass. The LEBLS project will upgrade a critically important component of the aging Sacramento River flood management system by providing additional capacity and resiliency to the Yolo Bypass. The project will also serve to enhance the regional ecosystem and support sustainable agriculture. LEBLS represents an essential first step toward implementing a system-wide approach to flood management in the Sacramento Valley. The primary feature of this project is the new seven-mile-long setback levee that is intended to increase the flood-carrying capacity of both the Yolo and Sacramento Bypasses. This new levee will also make future improvements to other flood structures like the Fremont and Sacramento Weirs possible, allowing for more floodwater from the Sacramento and American Rivers to flow into the Yolo Bypass. The LEBLS project cost is approximately $385 million and is the first step in the total Phase 1 project cost of $715 million.

On September 2nd, Sukut poured 180 cubic yards of concrete for the channel aprons on both sides of the double eight-by-six-foot box culvert. At the end, Sukut will construct eight cast-in-place box culverts.

The LEBLS project began in July of 2020, and construction is expected to continue for several years. The job will utilize multiple contractors and project partners such as Sukut Construction (Sukut). The Sacramento Area Flood Control Agency (SAFCA) contracted Sukut to perform all of the new interior drainage work associated with the new levee project. Matt Williams has been with Sukut for nine years and serves as the company’s area manager in Northern California. Williams is in charge of operations, including overseeing project managers and project engineers and performing overall business development. “We are building the interior drainage portion of the Lower Elkhorn Basin, which includes the installation of multiple concrete box culverts. However, as we continued to construct approximately seven miles of the earthen channel, which is designed to direct irrigation water to and from agricultural users, the need for more access points across the channel arose, and we are now contracted to build eight cast-in-place box culverts,” says Williams. “The new box culverts vary in length from 100 to more than 200 feet and are single, double, and triple wide, ranging in size from eight-foot by eight-foot to ten-foot by ten-foot. These boxes serve as access points for local farmers or public traffic on county roads to move freely over the ditches we are constructing.”

According to Williams, Sukut’s original contract value for constructing the interior drainage basin and channels was $11.6 million before adding the additional culvert box. “Our contract will include the installation of around 2,000 linear feet of reinforced concrete pipe (RCP) and 4,000 cubic yards of concrete for the box culverts. We will also place nearly 20,000 tons of aggregates, like Class II base, for backfilling the box culverts and for use on surface roads. All of the RCP was slurry-backfilled, a Yolo County standard when working within an existing or future county road right-of-way,” says Williams. Sukut started its work in September 2020 and is scheduled to wrap things up by October 2021. “We began by performing mass excavation of the eight-million-square-foot or nearly 200-acre drainage basin. We utilized 12 Cat 657 scrapers, which were new Tier 4 Final K-Models, or repowered E-Models, to meet project emission requirements,” says Williams. “The drainage basin was excavated down anywhere from two to five feet in depth for a total of around 750,000 cubic yards of earth moved. Total excavation on this job was approximately 1.25 million cubic yards when you factor in the seven miles of channel work,” adds Williams. The spoils were stockpiled on-site for future use on the overall levee project.

The completed invert for one of the box culverts.

Williams explains that the newly installed channel leads to a pump station that is being built by another construction firm. The pump station will rise above the new levee. “The basin is there to allow for additional capacity in the event of flooding or when pumps cannot keep up with demand,” continues Williams. “We are very accomplished at channel work and have our own unique and proven methods. All of the earthwork was accomplished with scrapers, bulldozers, and motor graders.” Williams says that the channel excavation varied from five to 25 feet in width at the bottom, and the tops of the channel ranged from 25 to 75 feet in width. “The channels are smaller where they begin to pick up water and get wider as they get closer to the basin and pump station. This is also the case with the construction of the box culverts,” explains Williams. “The entire earthen basin was drillseeded with ryegrass in 2020, and the local reclamation district will eventually farm the area with rice or another appropriate crop,” Williams adds.

Sukut crews pouring the sides of a concrete apron for one of the eight cast-in-place concrete boxes.

On this project, Sukut utilized 12 Cat 657 scrapers, which were new Tier 4 Final K-Models, or repowered E-Models, to meet project emission requirements.

According to Williams, one of the more challenging aspects of this project was coordinating between the property owners and ongoing land acquisitions. “This job began prior to all of the land being acquired within the easement of the project. We will, however, finish on time even after only working around half of the allotted days due to the numerous delays that came with both property acquisitions and the relocation of existing utilities,” says Williams. “There was also the component of self-performing all of the dewatering that was necessary to redirect water while widening the existing channels.” Williams says that, additionally, Sukut performed a small amount of asphalt paving and resurfacing of roads with aggregate. “A lot of credit is due to our amazing earthmoving crew of around 20 team members on the mass excavation in 2020 and approximately 12 throughout 2021. In addition, another 10 to 12-person crew has been working on the site carrying out the concrete work throughout this project,” concludes Williams. “I would like to thank and recognize the efforts of every single crew member on this project. Jim Penland has been our concrete superintendent overseeing the box culvert construction, while our superintendent, Greg Yarbrough, was responsible for the earthmoving in 2020 and superintendent Roger Gillam in 2021. We have exceptionally talented individuals working here at Sukut, and they need to be commended for continually serving above and beyond the call of duty.”

The excavation for the channel varied from five to 25 feet in width at the bottom, and the tops of the channel ranged from 25 to 75 feet in width.

Williams points out that Sukut worked closely and successfully with the local reclamation district and farmers and their associated properties, harvesting, and irrigation schedules. They have also worked alongside many other stakeholders, including the California Department of Fish and Wildlife, the Central Valley Flood Protection Board, the Sacramento Area Flood Control Agency, the Department of Water Resources, the United States Army Corps of Engineers, the United States Fish and Wildlife Service, the West Sacramento Area Flood Control Agency, and everyone from Yolo County and surrounding agencies. For more information on Sukut Construction, please visit their website at www.sukut.com or call their Santa Ana corporate office at (888) 785-8801. Cc