Dynsystem – Lessons Learned from 30 Years of Finite Element Modeling Applications

Presented on Monday, April 29, 2013
Robert H. Fitzgerald, P.E.1, Karen E. Kelley, PE1, Matthew Gamache, P.E., D.WRE1, Kristina K. Masterson, P.E., D.WRE2 and Brendan M. Harley, Sc.D., P.H., CEng2, (1)CDM Smith, Boston, MA, (2)CDM Smith, Cambridge, MA

Over 30 years ago, modelers at CDM Smith developed the nucleus of DYNSYSTEM, a suite of finite-element numerical modeling codes, for use in simulating groundwater flow and contaminant transport.  DYNFLOW is a fully 3-dimensional, Galerkin finite element flow modeling code, adapted from AQUIFEM, an earlier 2-dimensional code developed at MIT.  DYNTRACK is the companion solute transport code to DYNFLOW and uses the random walk method.  Through the years, the initial DYNFLOW and DYNTRACK programs have been frequently updated and supplemented to include features that allow the modeler to tackle ever more demanding modeling applications.  The advantages of the finite-element flow field representation have underpinned the successful application of the DYNSYSTEM codes to hundreds of model applications, including many that have posed significant technical challenges.

The basic elements of the finite element flow and random walk transport computations as implemented in DYNSYSTEM will be briefly outlined.  Selected advanced computational features of DYNSYSTEM will be introduced, including sharp-interface modeling of salt-water intrusion, coupled flow-transport (variable-density, multi-phase flow), groundwater-surface water interaction, and representation of soil/crop processes as they affect transient groundwater recharge.  Discussion will include practical features developed to aid the user, such as automatic rewetting of dry nodes, input/output capabilities for transient simulations, and utilities to facilitate import and export of data between the model and ArcGIS.

Brief examples of selected DYNSYSTEM finite element model applications highlighting these features will be presented, including an award-winning 1983 contaminant transport study, large-scale groundwater resource management modeling on Long Island in the 1990s, coupled flow-transport salt-water intrusion modeling of Savannah-Hilton Head, and recent examples of dual porosity solute transport, mass flux, and vadose zone vapor flow/transport simulations.

Robert H. Fitzgerald, P.E.
CDM Smith, Boston, MA
Robert Fitzgerald is a Senior Groundwater Modeler who has been responsible for numerous studies of groundwater flow and dissolved and separate phase contaminant transport in aquifers. He also has extensive experience in hydrology, hydraulics, and water resources management, emphasizing the application of computer simulation models. Fitzgerald has been responsible for the use of models in analyzing and developing programs for groundwater management and remediation, flood alleviation, reservoir yield augmentation, and water quality assessment.
Karen E. Kelley, PE
CDM Smith, Boston, MA
Karen Kelley is a water resources engineer specializing in the development and application of numerical models of groundwater flow and transport in complex and/or industrial settings with contaminants from multiple sources. Kelley has provided litigation support to industrial clients on projects involving groundwater contamination, water distribution systems, and toxic tort liability.

Matthew Gamache, P.E., D.WRE
CDM Smith, Boston, MA
Mr. Gamache is a water resources engineer who specializes in subsurface hydrologic and contaminant transport modeling. These models have been used to assess groundwater flow paths, travel times, and contaminant concentrations for litigation support, delineation of drinking water protection zones, and design of groundwater remediation systems. He received a M.S. from the University of Michigan and a B.S. from Worcester Polytechnic Institute.
Kristina K. Masterson, P.E., D.WRE
CDM Smith, Cambridge, MA
Kristina Masterson is a water resources engineer who specializes in groundwater flow and contaminant transport model simulation analysis. She has conducted groundwater flow and mass transport modeling studies for site environmental assessment, remediation investigation and design, remediation performance evaluation, and water resources management projects. During the 20 years that she has worked in the water resources engineering field, Masterson has successfully applied numerical groundwater flow and mass transport models to study groundwater flow patterns and contaminant mass transport characteristics in many different hydrogeological settings.
Brendan M. Harley, Sc.D., P.H., CEng
CDM Smith, Cambridge, MA
One of the nation’s leading practitioners in water resources planning and management, CDM senior vice president Brendan Harley has directed the development of urban water supply strategies and urban water quality control in major metropolitan centers throughout the United States and overseas. Dr. Harley serves as project manager and leading discipline expert on complex water resources projects, often combining technically challenging features with political issues requiring sensitive communication with multiple stakeholders, sustained interaction with government decisionmakers, and requirements for timely and clear interpretation of data.
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