Napa County Storm Repair Project - Knoxville Berryessa Site (Lake or Streambed Alteration Agreement No. 1600-2019-0276-R3)

Napa County Storm Repair Project - Knoxville Berryessa Site (Lake or Streambed Alteration Agreement No. 1600-2019-0276-R3)

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement number 1600-2019-0276-R3, pursuant to Section 1602 of the Fish and Game Code to Napa County Department of Public Works. The project will remove four 54-inch diameter corrugated steel pipes, which serve as a culverted bridge crossing that was damaged during the 2017 winter storms. It will be replaced with an approximately 25-foot long 29-foot wide free-span reinforced concrete bridge. The bridge will be supported on two approximately 12 feet tall, 5-feet wide concrete abutments and associated concrete footings. Four retaining walls, approximately 14 feet long, 6.5 feet tall, and 1-foot wide will be installed and extend out from the concrete abutments along the banks to provide bank stability. Approximately 14 cubic yards of ¼ ton rock riprap will be keyed in at the toe and extend up to the top of bank at approximately a 1 :1 slope to prevent undermining of concrete abutments and retaining walls. A layer of filter fabric will be installed on the banks prior to rock placement, and the bottom of the bridge will be approximately 1- foot above the 100-year water surface elevation.

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