Dixon 257 Project (Lake or Streambed Alteration Agreement No. EPIMS-SOL-54043-R3)

Dixon 257 Project (Lake or Streambed Alteration Agreement No. EPIMS-SOL-54043-R3)

The California Department of Fish and Wildlife (CDFW) has executed Lake and Streambed Alteration Agreement (EPIMS-SOL-54043-R3), pursuant to Fish and Game Code section 1602, to the project Applicant, Dixon Venture, LLC. The Project is limited to the construction of a stand-alone drainage system (system) which includes three types of activities and eight separate Projects: 1) mass grading and filling of streams (i.e., unnamed tributaries to Dixon Creek) (Project 1), 2) constructing a bypass swale (Project 2), and 3) new culvert construction for offsite flows and connection to existing culverts (Projects 3 to 8), as outlined in detail below. Stormwater from upstream properties will be routed through the newly constructed bypass swale and exit through an existing culvert under Pedrick Road. The bypass swale will receive water through newly constructed pipes on the western boundary (where the central ditch begins), head south, redirect east along the southern boundary, and then follow Pedrick Road north to an existing culvert, where it will leave the Project on the eastern boundary. The new swale will be culverted at new road intersections. This system will include a 25.14-acre retention basin with a volume of 240 acre-feet. Project 1: Grading and filling of 1.14 acres (7,603 linear feet) of streams with approximately 3,678 cubic yards of earthen fill. Improvements to Vaughn Road will consist of constructing an 18-inch diameter sewer pipeline parallel to Vaughn Road at an approximate depth of 16 feet below existing grade. The length of the sewer pipeline is approximately 650 feet. Additionally, the Project will be constructing roadway improvements to facilitate turn lanes at the intersection of Vaughn Road and Professional Drive. When completed, the existing roadside drainage will be restored to the existing flow conditions. This work is included in the impacts described above. Project 2: Construction of a 4.50-acre earthen bypass swale to route stormwater. The channel bottom of the swale will be approximately 8 feet wide. The side slopes will range from 10 feet wide (4:1 width-to-height) to 18 feet wide (3:1 width-to-height). Projects 3 to 5: Construction of three separate 60-inch inlets with a concrete base and 24-inch diameter pipes to capture and direct offsite flows from future road construction (Professional Drive). Projects 6 and 7: Construction of four 30-inch diameter high-density Polyethylene pipes with 30-inch diameter beveled metal flared ends and rip rap placement. The volume of fill is estimated to be 1,200 cubic yards, and approximately 40 cubic yards of rip rap will be placed at both ends of each culvert. The length of each culvert is approximately 150 linear feet. Project 8: Construction of a 60-inch inlet and connection via a 36-inch diameter pipe to the existing 36-inch culvert. Project 1 will result in permanent loss of 1.14 acres of streams. No additional impacts to streams will be associated with Projects 2 to 8.

Dixon

Solano

San Francisco Bay Area

Solano