Abstract
After a three-year planning, site investigation and design process, two Army-era landfills were removed from the steep 270 foot (80 meter) high bluffs above Baker Beach in the Presidio of San Francisco in 2007. The landfills had been created over a 50 year period during the last century by dumping of waste soil, construction debris and incinerator ash over the steep cliffs. High-value serpentine habitat and historic artillery batteries and earthworks surrounding the landfills, as well as locally unstable slopes prevented the construction of access roads to simplify the removal process. Despite extensive pre-removal site exploration and analyses, once excavation and removal began the landfills were found to contain nearly double the amount of waste that had been anticipated, resulting in a significant increase in project cost. By using a combination of paddle conveyors, “spyder “ walking excavators, off-road dump trucks and a bucket-brigade of long-reach hydraulic excavators the contractor was able to remove the waste soil and debris and adhere to the original project schedule. A project post-mortem indicated that additional drilling and sampling during the site investigation phase would have likely revealed the presence of thicker fill deposits, allowing a more accurate estimate of the eventual waste tonnage and better estimates of the project’s final cost, albeit at a significant increase in the cost of the investigation

William Godwin, PG, CEG 2020-2021 AEG President William H. Godwin is a member of the San Francisco Bay Area Chapter and has been working as an independent geologic consultant since 2014 and as an on-call employee for several large geotechnical consulting firms. Mr. Godwin most recently has provided expertise on water storage and conveyance facilities including large diameter high pressure water pipelines, earthen embankment dams and concrete spillways in California. Prior to 2014 he was Vice President of Nuclear Services for Fugro/William Lettis Associates, responsible for nuclear Quality Assurance and project management on geologic/seismic licensing (COLA) of nine next generation nuclear power facilities in the US and overseas. Mr. Godwin had previously worked at Harding Lawson Associates/MACTEC (now WOOD E&IS) managing geotechnical studies for geologic hazards at schools and hospitals, dam and reservoirs, environmental RI/FS and soil and groundwater treatment and remediation. Mr. Godwin was also employed at Bechtel Corporation working as a geologist for a variety of large power plant, rail transit, tunnel and CERCLA and RCRA environmental projects across the US and overseas. He initially started his career conducting seismic exploration for Petty Ray Geophysical across the midcontinent area of the US. Education/Licensure: Mr. Godwin earned a Bachelor of Science degree in Geology from the University of Redlands, in Southern California. He is a licensed Professional Geologist (PG) and Certified Engineering Geologist (CEG) in California. Other Professional Involvement: ASCE Pipeline Crossing Committee (2007) and Trenchless Installation of Pipelines (TIPS) Committee (2009); Secretary, Monterey Bay Geological Society (2014-present). He has attended and presented papers at six consecutive IAEG Congress meetings since 1998. He also led a field trip and was Subject Matter Expert for the Council of Examiners at the 2018 Annual Mtg of ASBOG.

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