Fish & Wildlife 3 (Napa)
(California Department of Fish and Wildlife, Region 3)
Wohler Road Bridge Retrofit Geotechnical Survey
NOE - Notice of Exemption
The project is limited to three geotechnical exploratory borings at the Wohler Bridge at Piers 2, 4, 5, to support the design of a seismic retrofit of the bridge. Piers 2 and 5 are located outside the active channel and will be accessed from an existing road. Pier 4 is located on a gravel bar within the river and will be accessed from an existing road and by crossing the gravel bar. A rubber-track mounted drill rig will be used to access all piers and no vegetation removal is anticipated. Each approximately 4- to 6-inches in diameter bore will be sample to a depth of approximately 120 feet. Approximately 8-cubic yards of soil will be removed from each bore hole. Plastic sheetings will be used in the work area to contain cuttings and any drilling mud/water. Straw wattles will be placed at ground surface surrounding the work area. Cuttings and drill fluid will be placed in drums and appropriately disposed of. Holes will be backfilled with cement grout and the upper 5 feet of the hole will be backfilled with native alluvial gravel. Issuance of a Streambed Alteration Agreement No. 1600-2014-0236-3 is pursuant to Fish and Game Code Section 1602.