Chiles Pope Bridge Replacement (Notification of Lake or Streambed Alteration, No. EPIMS-NAP- 30757-R3) Amendment

Chiles Pope Bridge Replacement (Notification of Lake or Streambed Alteration, No. EPIMS-NAP- 30757-R3) Amendment

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement EPIMS Notification No. EPIMS-NAP-30757-R3, pursuant to Section 1602 of the Fish and Game Code to the County of Napa. The Project is limited to the replacement of an existing bridge structure. The new bridge will be longer than the existing bridge in order to widen the creek channel and eliminate constriction posed by the existing bridge. The new bridge structure will consist of an approximately 105-foot-long by 26-foot-wide two-span cast-in-place prestressed concrete slab bridge that is two feet in depth. Two new abutments will be installed. Abutments will consist of a seat type abutment cap beam supported on soldier piles with ground anchors. One bent will be installed in the center of the channel to support the bridge, consisting of four 3-foot cast-in-place-drilled-hole shaft extensions. The Project will also install four new retaining walls. Pile installation for the retaining walls and abutments will be performed from the roadway. Excavation and installation of three retaining walls, abutment facing, and bent will be constructed from within the creek. A 30-foot-wide temporary access road into the creek will be created by grading the roadway approach and creek bank upstream of the existing bridge. A temporary stream diversion will be installed with cranes operated from the road and consist of an upstream cofferdam consisting of rock slope protection and sandbags, directing flow into two 24-inch diameter culverts that will extend 400 linear feet. The Project will result in temporary impacts to 0.22 acres and 450 linear feet of stream and riparian habitat from the temporary diversion of water and the installation of the temporary access road into the creek. The Project will result in permanent impacts to 239 square feet and 231 linear feet of stream and riparian habitat and will remove 24 riparian trees. This major amendment allow certain Project activities covered under the Agreement to commence before the Agreement Work Period start date of June 1 in order for the Project to be completed in one construction season. The Project activities covered under the major amendment are limited to mobilizing equipment, deploying protective measures and Best Management Practices, installing Abutment 1 and Abutment 3 (portion) and retaining wall 3 (portion), and installing soldier h-piles outside of the streambed and riparian area within the paved section and road shoulder of the Chiles Pope Valley Road bridge above Chiles Creek.

Napa

San Francisco Bay Area

Napa