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Notification#1600-2018-0116-R3 Streambed Alteration Agreement Page 2 of 16 PROJECT DESCRIPTION The Project is limited to the geotechnical investigation involving the collection of instream borings using a barge mounted drill. This project will provide subsurface and geological information for the larger Stockton Viaduct Rehabilitation Project. This Agreement covers the geotechnical investigation only and shall not be used for the construction of the larger project. This Agreement is limited to the following project activities: The Office of Geotechnical Design-North (OGD-N) is planning to perform barge- mounted subsurface investigation below the existing bridge decks at or near the proposed design pier/foundation locations located within the channel of the Stockton Deepwater Channel at the Port of Stockton in order to determine the types of foundation material at the site. OGD-N proposes to collect subsurface data necessary for the analysis of the current foundations and the preparation of the future foundation recommendations and to provide information for future construction procedures. The subsurface data will be used to generate a "Log of Test Boring" (LOTB). The LOTB is a contractual document that provides the subsurface information for the project site. The LOTB sheets are signed by a State of California Registered Civil Engineer or Registered Geologist and are included in the Caltrans Contract Plans. The subsurface data will be used to determine if a future retrofit project is feasible or to determine if future structure replacement would be necessary. The currently proposed borings will be referred to as the "Stage 2" geotechnical investigation. Stage 1 geotechnical investigations consisted of borings on land that were conducted in January 2018. Stage 2 geotechnical investigation activities are in-water borings currently scheduled to occur during August 2018. A separate Lake and Streambed Alteration Agreement will be necessary in the future to address the ultimate Stockton Channel Viaduct bridge retrofit or replacement project. The drilling locations at Bents 8 and 9 will require drilling from a barge. Due to the logistics involved in drilling from a barge and importance of these locations to the project, it is recommended to drill four (4) borings, two at each pier, to provide data for the retrofit and possible replacement. Borings will be composed of 4-inch to 6-inch diameter mud rotary drilled exploration holes extending to a maximum depth of 200 feet below the existing ground surface. Continuous sampling recovery of the soil materials will be achieved by utilizing the "punch-core" barrel sampling with a finger-bit and the Standard Penetration Test (SPT) sampler. All soil samples drilled will be collected for field identification and geotechnical laboratory testing. Samples not selected for testing will be containerized in mud drums for disposal. Upon the completion of each boring, the borehole will be sealed with bentonite chips or alternate material such as cement grout, specified by any regulatory permits. It is anticipated that it will take four to 6 (4-6) weeks to complete the Stage 2 drilling. A drill rig placed on a barge will be transported by a support boat to the boring locations. It will take two (2) days to assemble the barge and another two (2) days to disassemble the barge at a boat launch facility. It is expected that the barge would be assembled, equipped, and launched from a marina facility at the Stockton