AgdaPkt 2016-12-12 Closed and Joint SA PFA

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6.1.A. - Page 22 Final geotechnical exploration locations will be developed by Wood Rodgers and CE&G based on a screening review of creek sections and structures from the initial site visits and from the Basis of Design Memorandum. Prior to completing the subsurface exploration, Wood Rodgers Team will obtain permits from San Mateo County Environmental Health Services Division and the exploration locations marked for Underground Service Alert (USA). The subsurface conditions in the vicinity of proposed channel replacement areas identified from site visits and results from the Basis of Design Memorandum will be explored by drilling and sampling geotechnical borings along the channel bottom or at the top of the channel if there is adequate right-of-way to work within. The borings will be advanced by first coring through the concrete lining where required and drilled using a portable Minuteman drilling rig equipped with solid flight augers. Samples of the site materials will be recovered from the borings using California Modified and/or Standard Penetration samplers. Selected samples recovered from the borings will be returned to our soils testing laboratory for index properties, consolidation testing, and/or strength testing. It is estimated that borings will be advanced to between approximately 20 and 35 feet deep or approximately 10 feet below anticipated temporary shoring pile depths. The borings will be grouted in accordance with San Mateo County requirements and core holes sealed with concrete backfill. Soil cuttings will be collected in drums and disposed of in accordance with state, federal, and local regulations. Work anticipated to dispose of the cuttings assumes that the cuttings will be classified as non -hazardous materials. The costs assume that the geotechnical borings will be limited to 2. Additional borings can be completed at additional cost — see Task 6. The results from the field exploration, laboratory testing, and background research will be used as the basis for development of geotechnical design parameters for replacement of concrete channels and be presented in a separate geotechnical report for each project reach. The reports will include the following: • Introduction including site location, description, and purpose of the investigation; • A summary of the information collected from previous reports in our files in the vicinity of the proposed improvements; • Subsurface conditions and geology; • Loading and groundwater design criteria for temporary shoring and permanent structure design; • Analysis and channel design recommendations; • Boring logs and test results from the exploration program; and • Findings and geotechnical recommendations pertaining to the design parameters for the planned project. REV: 12.01-16 RL Page 18 of 23 ATTY/AGR.2016.325/Wood Rodgers, Inc.