Caltrans Box Culvert Cleaning

CLIENT: Caltrans
LOCATION: Sonoma, California
SERVICES: Pipe Cleaning, Asset Management


A 4×4 box culvert in Sonoma that carries all storm run off from a local hillside had become 100% full of silt, roots, and debris. Caltrans contacted our team to clean the box culvert and restore its structural integrity, because during storm events water failed to pass through the culvert and found a path of least resistance through a cattle pass. The cattle pass began to erode underneath the freeway, resulting in a sinkhole developing under an active highway.


Pipe & Plant was tasked by Caltrans to clean the box culvert and restore the structural integrity of the cattle pass so storm water could flow freely to a nearby estuary. This project was located in a remote area, requiring our team to develop creative engineering solutions to solve the problem.


Environmental: As a result of water not being able to flow effectively, a grove of trees and foliage had developed around both sides of the freeway. Pipe & Plant had to clear and grub, build access roads, while preserving an environmentally sensitive work area for rare birds that had migrated to the construction right of way.

Safety: All work had to be conducted off of the shoulder of an active highway with a speed limit of 55 miles per hour. Significant traffic control, ingress and egress challenges had to be engineered to provide a safe working environment

Water: The location of the project was 8 miles away from its closest source of jetting water. Pipe & Plant developed a sophisticated onsite water recycling system, where we imported 40,000 gallons of recycled water from a nearby waste water treatment plant. We recycled the water on site for the duration of the project, in effect saving over 3,000,000 gallons of water during the cleaning process. At project completion the used jetting water was determined to be uncontaminated and was applied as irrigation to cattle grazing land in the vicinity.

Design: Because of the urgency of the situation, the Department of Transportation did not have adequate time to design the solution to its problems with an engineering team. Pipe & Plant furnished a Civil Engineering team to develop the design, self-performed all of the work, and delivered a project on time and under budget.

  • Clear and Grub
  • Excavation
  • Compaction
  • Drill and Dowel
  • Concrete Reinforcement
  • Structural Concrete
  • Paving
  • Pipe Cleaning
  • Pipeline Inspection and Condition Assessment
  • Water Recycling
  • Environmental Remediation