The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement, EPIMS-SHA-22816-R1I, pursuant to Section 1602 of the Fish and Game Code to the Great Shasta Rail Trail Association, as represented by Jerry Harmon.
The scope of construction activities authorized by this Agreement is limited to the replacement of the existing bridge at Dry Creek with a new bottomless, multi-plate culvert that is 16 feet wide, 30 feet long, and sized to convey 100-year stormflows. The new culvert will be installed on 30-foot continuous concrete footings approximately three feet wide and two feet deep, with engineered backfill placed on top of the crossing to match the adjacent trail elevation. Rock slope protection (RSP) will be installed at the upstream and downstream ends of the culvert for erosion and scour protection (Project).
The existing stream channel will not be modified or disturbed by heavy equipment, as machinery will operate from the existing rail bed to remove all existing bridge materials and place new materials. Installation of the footings for the culvert will result in temporary disturbance in areas outside of the existing channel where the current bridge foundation is located. Prior to the placement of the culvert, the alluvium in the stream channel adjacent to the footing will be re-compacted or RSP will be added. The culvert will then be grouted into the footing and engineered fill will be placed on the outside of the culvert and compacted.
To stabilize the northern bank of the stream downstream of the crossing, large woody debris (LWD) will be installed on the bank to provide scour protection. Installation of LWD will include anchoring of root wads along 30 linear feet of the northern bank of the stream. The root wads will be bolted to spiked anchor logs installed vertically within the bank, and RSP will be placed around the installation of the LWD.
The project will require the removal of several trees within the channel, bank, and riparian corridor of the stream, including one Douglas fir (12 inches diameter at breast height [DBH]) and one cedar (10 inches DBH) on the southern side of the crossing. Several trees less than six inches DBH may also be removed to access work areas.