Approve agreement with MBK Engineers in the amount of $396,875 for the period of July 1, 2024, through March 15, 2026, for project management and engineering services in support of the Huff's Corner Levee Raise & Channel Reconfiguration Phase II Project; and approve associated sole source request. (No general fund impact) (Lindbo/Sabatini)

The Huffs Corner Levee Raise and Channel Reconfiguration Project has been underway since 2019, with MBK Engineers ("MBK") serving as the Project Manager and lead design engineer for the levee raise project component. The agreement before the Board pertains to MBK's involvement with "Phase II" of the Huff's Corner Project, details of which are described below.  

Services to be provided by MBK in this agreement include overall project management, support of the levee raise project component (including engineering and design, construction management, biological and cultural monitoring), support of the in-channel repair project component (including construction management), and support for the project's environmental permitting needs.  It is expected that construction activities for both the levee raise project and in-channel repair project will be completed in Summer 2024.  

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, Yolo County, through the Central Valley Flood Protection Board, initiated the process of forming a Maintenance Area for the maintenance of the levee. However, 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 and 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 and Channel Reconfiguration Project.

In August 2019, the County and the California Department of Water Resources ("DWR") entered into a Project Agreement to complete the design, environmental permitting, and construction of the overall project features. Utilizing funds provided by the agreement, as well as local funding contributions, 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. Due to unforeseen costs associated with construction, environmental mitigation, and securing land acquisition/right-of-way, the Project Agreement did not contain sufficient budget for the construction of the levee raise project component. 

In April 2024, the County and DWR entered into a Project Partnership Agreement to fund "Phase II" of the project, which will finish the project by constructing the levee raise project component, in addition to repairing the in-channel reconfiguration project that was damaged by 2022-2023 winter flows and implementation of an off-site mitigation project. 

A sole source request has been prepared for this agreement. The request has been included as Attachment B to this staff report.