Stockton Channel Viaduct Project, In-Water Sampling (10-0X460) (Notification of Lake or Streambed Alteration, No. EPIMS-SJN-52108-R3)

Stockton Channel Viaduct Project, In-Water Sampling (10-0X460) (Notification of Lake or Streambed Alteration, No. EPIMS-SJN-52108-R3)

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement EPIMS Notification No. EPIMS- SMO-49548-R3, pursuant to Section 1602 of the Fish and Game Code to California Department of Transportation (Caltrans). The Project consists of barge/boat-mounted in-water sampling of channel sediments using a hand-held fathometer and a Vibracore sediment coring device. Six boring locations will be established to characterize sediment throughout the project area. Boring location coordinates, collection dates, water depths, mudline depths, and the physical characteristics of each core will be noted. Barge or boat will be launched from the Morelli Park boat launch on the south side of the channel. The sampling effort will result in the collection of six (6) 6-inch diameter by 20-foot deep sediment cores. Each borehole would result in a temporary impact area of 28.26 square inches (0.20 square feet) and each core sample would be 4.0 cubic feet in volume. The sampling activities will be limited to the short duration in-water work period of no more than three (3) to five (5) non-consecutive days. Core tubes will consist of polyethylene liners inside a 2 to 4-inch outer diameter aluminum core barrel with a stainless-steel catcher to retain the sediment. Using an outer casing closed system technique for the in-water borings creates a sealed system preventing upstream or downstream sedimentation and turbidity during boring. No backfill is proposed once the coring is completed. No dewatering activities are proposed and no cofferdams are required to perform the geotechnical drilling operations. Best Management Practices (BMPs) will be deployed around and beneath all drilling equipment for barge-mounted borings and an emergency spill response plan will be implemented fourteen (14) days prior to construction activities. The Vibracore drilling device drives the sampling tubes with a high-frequency-low-amplitude vibrating device. The entire Vibracore device is lightweight (only 75 lbs.) and the portability of the device makes it suitable for one-man operation on small vessels. During non-working hours, all equipment will be staged at the top of bank on existing paved areas, or in the paved parking lots or right of way adjacent to the work area. Temporary construction access (i.e., worker and equipment ingress and egress) will occur from top of bank upland areas via boat ramp and will avoid encroaching on waters and wetlands to the extent feasible.

Stockton

San Joaquin

San Francisco Bay Area

San Joaquin