In 2020, a small collective of Western Oregon University Earth and Environmental Science Department graduates and faculty took the first steps toward creating a science-focused alum group. The society promotes student success and career outcomes in the geosciences, along with values of inclusion, integrity, shared knowledge, collaboration, and sustainability. These values align with professional associations like AEG, including DEI.

This presentation will share the startup story of the Earth Science Alumni Society and discuss the potential to create similar groups as a strategic vehicle for positive action and change. It will be delivered with Dr. Jeff Templeton and Dr. Steve Taylor from Western Oregon University, Rachel Pirot from Weyerhaeuser, Dan Wagner from Geobrugg, and Nichole Niskanen from Central Geotechnical Services.

The Del Puerto Water District (DPWD) and San Joaquin River Exchange Contractors Water Authority supply Central Valley Project water to farmlands in five California counties. A new reservoir is proposed to improve water reliability and storage in the service area, providing 82,000 acre-feet of locally controlled off-stream storage. The feasibility study included reviewing published data and aerial photographs and conducting geologic site reconnaissance, a desktop fault study, a preliminary field investigation and laboratory testing program, and ground motion assessments, including deterministic and probabilistic seismic hazard analysis.

Given the project location on the eastern flank of the Diablo Range, part of the northwest-trending Coast Ranges, and along the western margin of the San Joaquin Valley, two Quaternary-active fault systems were evaluated. This presentation will discuss the approaches used to evaluate the geologic and seismic hazards, including interpretations of the feasibility study.

Geoprofessionals play an essential role in dam safety, especially regarding the foundations of all dams and the embankments of earthen dams. One of the challenges geoprofessionals often encounter when evaluating dam performance or conducting dam safety reviews is the availability of design and construction documentation. For older dams, especially those that have had more than one owner, records are often limited, particularly construction records related to foundation excavation and treatment, borrow areas, embankment materials and placement, and design changes during construction. In these cases, the geoprofessional must assume the role of detective, digging deep into other information sources.

This presentation provides several case studies in which geoprofessionals utilized construction photographs, inspection reports, news articles, and other information to understand the foundation and embankment conditions better, identify conditions that may not be accurately reflected on the as-built record drawings, and inform the evaluations of dam performance and the development of risk estimates for potential failure modes.

Observation wells and Casagrande piezometers (or open-standpipe piezometers) are commonly installed in embankment dams and levees to measure water levels and pore water pressures, respectively, to model phreatic and piezometric surfaces. In June 2022, a research team including dam safety professionals and geotechnical instrumentation vendors began an investigation into field discrepancies between manual and automated vibrating-wire piezometer water level measurements of Casagrande piezometers, which were sometimes several magnitudes greater than the specified accuracies of the sensor. An overview of the laboratory and preliminary findings were presented at the 2022 AEG Annual Meeting.

This presentation will draw conclusions from data collected over the 2022-2023 water year, surmise potential causes for discrepancies between manual and automated measurements, and suggest practical recommendations for improving the accuracy of and monitoring Casagrande piezometers at embankment dams. The session will be co-presented with Rob Clark from Geokon and Josh Brown from Campbell Scientific.

Identifying coal mining and mine subsidence features is key in assessing mining conditions at a site. This presentation provides examples of mining features, such as company towns, beehive coke ovens, coal refuse piles, mine entries, slopes, shafts, and foundations for infrastructure, that indicate the presence of mining nearby. It will also include subsidence features like sinkholes, troughs, and ground cracks, with examples of impacts on residential dwellings and infrastructure. Also included will be examples of acid mine drainage and mine fires. The presenters will share images of mining features from the time of active mining to compare past and present conditions. Features will also be tied to mine maps to show mine-level conditions. Illustrations of subsidence mechanisms and coal mining regions will also be provided.

In 2022, intense rainfall increased water flow in eastern Ohio’s Cross Creek. This surge in water eroded the toe of the slope of a previously remediated road in Jefferson County and triggered an emergency slip. The existing 105-foot-long soldier pile wall, consisting of steel piles and timber lagging with dead men tiebacks, experienced intense erosion below the timber lagging, reducing the passive resistance of the wall. The erosion exposed some of the existing wall below the dredge line, destabilizing the slope supporting the road. The urgent circumstances and limited budget for a survey necessitated the utilization of drone footage to create a 3D model of the area and generate the most recent topography.

The new remediation consists of stabilizing the existing wall with rock anchors, installing a toe wall to protect the existing wall from further erosion and loss of passive support, as well as installing two walls at each end of the existing wall, and armoring the streambank within the limits of the proposed remediation. The presentation will discuss the project, from emergency onsite reconnaissance to concept and design and overcoming the expedited process using drone technology.