Approve agreement with the Yocha Dehe Wintun Nation for acquisition of a permanent flood control easement in support of the Knights Landing Flood Management Project. (No general fund impact) (Lindbo/Sabatini)

A permanent easement acquisition is required on this property for the Knights Landing Flood Management Project ("Project"). An independent appraisal was prepared by a licensed appraiser with Pattison & Associates, Inc. to determine the value of the easement interests the County must acquire for the Project.  County staff worked with the property owner to come to a mutually acceptable agreement for the easement purchase and compensation. 

Background
The Knights Landing Flood Management Project is a multi-phase project that includes infrastructure improvements to the Sacramento River Levee, the Knights Landing Ridge Cut levee, and other flood control infrastructure in this area. This project will reduce or prevent flooding to a population of 995 (Knights Landing), approximately 321 structures, and 3,500 acres of prime agricultural lands. The subject property is along what is known as Site 11, which will require a combination berm to address stability, and under- and through-seepage. 

A seepage-stability berm is constructed on the landside of a levee, using soils to reinforce the existing top stratum and to reduce under-seepage pressure near the toe of the levee and to protect the levee toe during high flow events in the Sacramento River.  Remediation work at Site 11 will consist of installing a drained seepage-stability berm.  The work will involve (1) constructing a drained seepage-stability berm on the landside toe of the levee, (2) relocating drainage ditches, and (3) reseeding the berm with native vegetation to reduce erosion.

An 80-foot-wide, maximum width, drained seepage-stability berm would be constructed on the landside of the levee continuing north from the intersection of CR 16 and CR 116B approximately 5,600 feet to the north end of Site 11. The seepage-stability berm consists of a 2-foot-thick layer of drainage rock below a 3-foot layer of earthen material. The thickness of the berm would be 5 feet at the landside levee slope and decrease to 3 feet at the landside toe of the berm. The seepage stability berm at Site 11 would require relocating the existing irrigation ditches that are located at the toe of the levee. The existing irrigation ditches would be filled in and compacted, and then relocated by the irrigation ditch landowners based on their irrigation needs and outside of the Proposed Project limits, adjacent to a proposed 15-foot width maintenance easement. In addition to these irrigation ditches, piping for two pump stations is located within the footprint of the seepage-stability berm. The piping would need to be extended and relocated from its current discharge location near the landside toe of the levee to connect with the pump stations. The new piping would be constructed on top of the seepage-stability berm and covered with 1.5 feet of fill.

The construction of the Project requires several temporary easements to allow for construction, stockpiling, and staging areas. 

In addition, two permanent easements are required to accommodate the construction of Mid-Valley Site #11. One of these easements is the subject of this proposed Board action: a 3.93 acre permanent flood control easement on parcels 056-230-011 & 056-220-020, owned by the Yocha Dehe Wintun Nation, for the amount of $68,800.
 

The agreement for purchase has been approved by the Yocha Dehe Wintun Nation. Accordingly, staff recommends that the Board: 

County Counsel approved agreement as to form. Staff have collaborated extensively with the subject landowner, in addition to all landowners in the Knights Landing basin affected by the project.

Not applicable