Brown and Caldwell Inc. 3/9/2022 Amendment 1

Portal 4 Improvements Geotechnical Services Scope of Work 5. All non-contaminated drilling spoils and related debris will be drummed on site and transported off site for disposal by drilling subcontractor. 6. HWA will be responsible for all post drilling clean up. 7. Any standpipe monitoring wells installed as part of this investigation will be maintained throughout design. Monitoring wells will be abandoned by the Contractor, in accordance with Ecology requirements. 8. Phase 1 or Phase 2 Environmental Site Assessment are not included in this scope of work. 9. Neither seismic or site specific PSHA nor site specific response analyses are included in this scope. 10. Design and implementation of any dewatering systems will be the responsibility of the contractor. Estimated flow rates provided under this scope are intended for planning level purposes. 11. Boring locations will be located using handheld GPS and measurement from existing know features. 12. Utility locates, via the One-Call Utility Locate Center, will be comprehensive and accurate enough to allow reliable and safe location of borings. Vacuum extraction of borings is not included. 13.Soil samples will be collected form borings using the Standard Penetration Test (SPT) at intervals of 2.5 feet to a depth of 20 feet and at intervals of 5 feet to the depth of termination. 14. Preliminary infiltration analysis will be performed using grain size data collected from field explorations. No PIT tests or EPA falling head (percolation)tests will be completed as part of this scope of work. 15. Does not include providing PS&E level design if ground improvement methods or preloading were to be considered. 16. Following finalization of the geotechnical report, all soil samples will be disposed. Long-term storage of soil samples by the Consultant is not included. IBrown AND Caldwell 5 Attachment A Geotech Services SOW