Samuel McWilliams, E.I.T.

Pier 39 Hydrodynamics and Sediment Stability Assessment, San Francisco, California — Led a field and desktop study of hydrodynamic, wave, and sediment stability conditions via SEDflume within the site. Data collected were used to calibrate and validate a coupled wave and hydrodynamic numerical model to yield criteria for remedial design. Analyzed a range of hydrodynamic conditions up to 100-year storm conditions to support remedy efficacy decisions throughout the site.

Terminal Sedimentation Analysis, Vallejo, California — Conducted a study on changes to sedimentation rates and the need for dredging activities due to reconfiguration of the ferry pier. Applied a calibrated and validated numerical model resulting in spatial assessments of deposition potential that were paired with estimates of sedimentation rates from bathymetric surveys. Results of the study informed the engineering design team on potential site response from possible pier reconfigurations and suggested a potential reduction in maintenance dredging frequency.

Marine Energy Effects on the Environment-Sandia National Laboratories — The U.S. Department of Energy’s mission to develop a robust and safe renewable energy infrastructure requires that stakeholders, permitting agencies, and developers understand and mitigate negative effects to the environment. To support that understanding, worked to develop application methods for numerical models that simulate the effect wave and current energy conversion technology have on their surrounding environment. This has resulted in the development of the Spatial Environmental Assessment Tool to quantify and compare potential power production and risk to the environment.

Contaminated Sediment Transport Evaluation, Berry’s Creek Study Area, New Jersey — Supporting the RI/FS process to characterize fate and transport of sediment-bound contaminants. Responsibilities include calibration and validation of hydrodynamic and sediment transport model results with respect to measured data sets regarding hydrodynamic conditions, sedimentation rates, and anthropogenic developments.

Marine Renewable Energy Support, Sandia National Laboratories — Supporting the development of tools and techniques to improve performance, lower costs, and accelerate the deployment of marine and hydrokinetic energy technologies. Participated in the assessment of potential alterations to the marine environment due to the deployment of these devices as well as optimization of array configurations.

Suspended Sediment Plume from Underwater Blast, San Francisco Bay, California — Performed a modeling study after the removal of the eastern span of the Bay Bridge in San Francisco Bay, potentially posing threats from suspension of sediments to environmentally sensitive areas. The modeling results yielded a theoretical path and residence time estimate for the sediment plume near the environmentally sensitive areas. Assisted in developing monitoring and mitigation plans to track and reduce the potential for harm within the bay.

Estuarine Larval Transport, Mosquito Lagoon, Florida — Developed assessment techniques utilizing hydrodynamic models to determine optimal locations for submerged artificial oyster reefs. Oyster reefs are a bioindicator of a healthy estuarine ecosystem acting as nurseries, food source, and contaminant sink through their filter feeding processes.

Mid-Barataria Bay Sediment Diversion SEDflume Study, Southeastern Louisiana — Conducted a SEDflume study of native Barataria Bay, Louisiana sediment to support engineering design of a proposed diversion of the Mississippi River. The increased hydrodynamic forces from diverted discharge are expected to erode material near the mouth of the diversion structure. Led a SEDflume study of bed material extending from the surface to 120 ft below mudline to support numerical models simulating flows and estimating the potential for erosion. Study results supported modeling efforts to predict the potential for scour within the system and support the engineering design process.

Dredge Material Study for Beneficial Reuse, Maryland — Conducted a SEDflume study to compare the erodibility of placed dredge material with dredge material supplemented with recycled glass or sand. Test samples were developed in the laboratory by mixing a slurry consisting of supplemental and dredge material. Three test samples were developed for each mixture and allowed to consolidate for 1, 7, and 28 days to compare erodibility over time. The SEDflume study produced measurements of erodibility relative to depth and highlighted the differences in mobilization potential for each material type. The results will help inform appropriate beneficial reuse dredge material management practices for use in restoration projects.

Instrumentation Monitoring for Newtown Creek Hydrodynamic and Sediment Transport Modeling, New York — Deployed an array of sensors to collect real-time data regarding free stream and near bed currents, water quality parameters, and suspended sediments concentrations. Data collected will be used to evaluate remediation techniques.

SEDflume Sediment Erosion Rate Study, Mozambique — Analyzed samples to support deep-water drilling efforts. Application of pre-determined shear stresses to relatively undisturbed sediment cores allowed for the determination of critical shear stresses for erosion with depth. Sediment properties such as vane shear, bulk density, and particle size distribution, in conjunction with the critical shear stress information help to ascertain potential issues when working with these sediments in their natural environment.