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

Portal 4 Improvements Geotechnical Services Scope of Work Part 3 of 3: Engineering Analysis, Report Preparation, and Assumptions Recommendations The geotechnical consultant shall provide the requested design information, associated recommendations, and other identified in Part 2 for the specific structures and pipelines, site-related activities, and other project features that are supported or impacted by soils. Report The geotechnical consultant shall provide in a report format the following information, which should be inclusive of all scope items and the following: • Summary of the project. • Scope of work geotechnical performed. • Field activities including equipment used. • Summary of all subsurface exploration data, including subsurface soil profile, exploration logs and locations, laboratory or in situ test results, groundwater information, and other specific lab tests. • Interpretation and analysis of the subsurface data. • Specific engineering recommendations for design. • Discussion of conditions that may lead to problems or challenges and recommended mitigation steps. • Any specific design assistance tasks. Services During Construction The geotechnical consultant shall provide results from the following tests as part of the services during construction field activities: • Backfill import aggregate acceptance testing as WSDOT sampling rate (assume 1 source) • Acceptance testing of native material for possible use on site. • Proctor tests on materials to be compacted. Assumptions 1. All required rights of entry will be provided to HWA at no additional costs. 2. Drilling will be accomplished during normal daylight workdays and hours, with at least a minimum 8 hours available per day. 3. Boring locations will be accessible by truck-or truck-mounted drill rigs. 4. The geotechnical explorations proposed herein will not be used to assess site environmental conditions. However, visual or olfactory observations regarding potential contamination will be noted. Analysis, testing,storage, and handling of potentially contaminated soil and ground water )(either sampled or spoils from drilling) are beyond this scope of services. If contaminated soils and/or ground water are encountered,the material will be properly contained on-site for disposal as mutually agreed upon without additional cost to HWA. IBrown AND Caldwell 4 Attachment A Geotech Services SOW