On July 23, 2024, the Board of Supervisors approved Agreement No. 24-206, a construction contract with Martin Brothers Construction in the amount of $359,656, for the Huff's Corner In-Channel Repair Project (see Minute Order No. 24-72; Item No. 7).  Additionally, the Board authorized the Director of Community Services to approve change orders to the construction agreement, consistent with the applicable change order limits of the Public Contract Code, up to a cumulative total of 10% of the contract's value ($35,965.60).

On September 25, 2024, the Director of Community Services approved Contract Change Order No. 001 ("CCO No. 001") in the amount of $29,968.10, authorizing the contractor to implement temporary measures to divert active creek flows away from the project's construction limits.  These measures included the construction of a diversion trench and the installation of a downstream silt fence. 

The In-Channel Repair Project was completed in late 2024.  In the months since, the Department has worked with the contractor to develop Contract Change Order No. 002 ("CCO No. 002") in order to align the final contract budget with actual project expenses.  CCO No. 002 includes the following changes to the contract, which result in a net increase to the contract of $129,674.36:

The final project quantities were reviewed by the County's contracted engineering design team and were found to be reasonable. 

As part of the Board's actions on July 23, 2024, a project contingency budget equal to 10% of the contract value was authorized. For the reasons outlined above, this project contingency budget will also need to be increased.  Increasing the project contingency budget also requires Board approval. 

No further expenses under the construction contract are anticipated, as CCO No. 002 represents the full and final resolution of all contractor-requested change orders and claims related to the project.  The final agreement budget stands at $519,298.46, as illustrated below:
 

Original Contract Total	$359,656.00
CCO No. 001	$29,968.10
CCO No. 002	$129,674.36
Total	$519,298.46

Background
The section of Cache Creek known as "Huff's Corner" is a small reach on the right bank extending approximately 2,700 feet upstream from Interstate 5. The levee was initially constructed by the U.S. Army Corps of Engineers in 1960, and Yolo County has been the local maintaining agency since its construction. Only the eastern 1,500 feet of this levee is within the State Plan of Flood Control.

In October 2012, the County, through the Central Valley Flood Protection Board  ("CVFPB"), initiated the process of forming a Maintenance Area for the maintenance of the levee. The Maintenance Area was not formed because the initial cost of completing the deferred maintenance required for the formation of a Maintenance Area was prohibitive to the County and local landowners.

In early 2018, the County sought engineering recommendations to determine what would be required to complete the deferred maintenance to restart the Maintenance Area formation process. In addition to the deferred maintenance, two major project improvements were identified: (1) a raise of the entire reach of the levee to restore it to its original design height, and (2) implementation of a "reconfiguration" project within the Lower Cache Creek channel to control erosional forces against the levee and remove excess sedimentation. These two improvements were combined to create the Huff's Corner Levee Raise & Channel Reconfiguration Project. However, a portion of the levee raise was determined to be unnecessary based upon further information from the US Army Corps of Engineers, the CVFPB, and the CA Department of Water Resources ("DWR") confirming that there had not been a prior levee constructed on an approximate 0.4-mile section of the levee.

In August 2019, the County and DWR entered into a Project Agreement to complete the design, environmental permitting, and construction of the overall project. Utilizing funds provided by this agreement, as well as local funding contributions from the Cache Creek Resources Management Plan fund, the County was able to develop 100% designs for both project components, secure all necessary permits and environmental clearances, and complete the in-channel reconfiguration project component. Because of unforeseen project costs and change in the scope of the levee raise component of the Project, County efforts were first focused on the in-channel reconfiguration project component, which was completed in late December 2022. This project involved the removal of an in-channel sediment island adjacent to the levee that had been accumulating in the creek for decades, and the construction of a sacrificial terrace along the right bank of the creek. Shortly after construction concluded, a series of early 2023 storms brought significant flows through the channel. Because the recently disturbed soils had not been fully stabilized by the seeded vegetation, approximately 285 linear feet of the newly built terrace was eroded away by the creek flows.

In April 2024, the County was able to secure additional funding from DWR to complete "Phase II" of the project, which includes the repair actions needed to rebuild the washed-out portion of the terrace. The repair work included the following activities, and is holding up well after the 2024-2025 winter:

The Phase II effort also included funding for the Levee Maintenance Project, which was also completed in late 2024, under a separate agreement by a different contractor.