Yellow Crek Bridge, Replacement Project (Lake or Streambed Alteration Agreement No. 1600-2015-0218-R2)

Yellow Crek Bridge, Replacement Project (Lake or Streambed Alteration Agreement No. 1600-2015-0218-R2)

Note: Reference SCH # 2013128281 The proposed project will involve removal of the existing Yellow Creek Bridge and construction fo a new bridge on the same alignment. The new bridge will include a single span, cast in place (CIP) pre-stressed (PS) concrete box girder structure. The following components are included as part of the project: A single 204.5-ft long single span (CIP/PS box girder structure with a total of five girders; two 12 ft. wide lanes, an 8 feet wide left shoulder and a 12.5 feet wide right shoulder for a total bridge width of 48 feet; pile foundations using 24-inch diameter cast-in-drilled hole (CIDH) concrete piles with permanent casing placed for new foundations; seat Type bridge abutments, using 2 feet diameter CIDH piles; two Type 1 retaining walls constructed on both ends of the bridge parallel to the Feather River, and excavated to an approx. depth of 10 feet supported on 24-in. diameter CIDH piles with permanent casing: one retaining wall with the length of approx. 152 feet and height of 10 feet, the other with a length of 80 feet and a height of 14 feet; Rock slope protection (RSP) will be placed along the banks of Yellow Creek in front of the retaining walls and the retaining walls that parallel the North Fork Feather River (NFFR). The RSP will be approx. 6.5 feet thick. The toe of the RSP bank will be "keyed-in" approx. 10 feet deep. Placement of RSP will require excavation, and excavation may require driven sheet piles to be use as cofferdams; Clear water diversion to key the bottom of RSP into the streambed along the banks of Yellow Creek and the Feather River. Diverting the flow of creek and river may require driven sheet piles to be used as cofferdams; Temporary work trestles will be installed in Yellow Creek or equipment access into the channel and work above the high water outflows of Belden Power House. Temporary falsework will be installed in Yellow Creek to support the new bridge structure while it is being constructed. The temporary trestles and falsework may be required to be left in the creek over winter, replacement of existing culverts west of the new bridge require trenching up to depth of 10 feet. The existing culvert will be replaced with a 24-inch culvert; removal of the existing bridge will include the demolishing of the existing deck, girders, and the removal of bridge piers and pier foundation; clear water diversion to remove the existing piers and pier foundations, removal will require excavation to a depth of five feet and may require driven sheet piles to be used as cofferdams; installation of a down drain west of the new bridge. The purpose of the down drain is to prevent erosion from undermining the area below the outlet and to keep the fill slope from becoming incised and destabilized. The current system lacks end treatment to stabilize and protect the embankment from erosion; grading for two ditches near the PG&E driveway up to a depth of 8 feet. The existing culvert will be replaced by a new 18-in culvert; grading for 300 ft. of roadway reconstruction on the west and east approach which involves 2 feet of excavation, and re-contouring and grading up to a depth of 10 feet; Type 80 bridge barriers modified with architectural texture to mimic existing Douglas fir wood bridge rails; relocation of buried utility vaults is anticipated to take place. the maximum depth of these excavation; and, a temporary gravel pad is proposed within Yellow Creek to provide construction access along the north side of the bridge, extending form the west bank to pier 2 (approx. 110 feet in length). The gravel pad would have an approx. top width of 13 feet and bottom width of 70 feet, with an average depth of 2.5 ft.

Plumas