Key Staff

Dynamic Solutions, LLC is a federally certified woman-owned small business which maintains a staff of largely senior-level engineers and scientists who are experts in their respective disciplines. The DSLLC staff includes the disciplines of: Project Managers, Hydrology and Hydraulics (H&H) Engineers, Coastal Engineers, Civil Engineers, Environmental Engineers, Geologists, and Biologist/Ecologists. They have experience with numerous modeling and software programs for developing flood frequency curves and simulating hydraulics including HEC-SSP, HEC-DSS, HEC-RAS, and many others. Key staff members are introduced below.​

Our Team

Julie A. Wallen 
President, Mechanical Engineer

​Ms. Wallen, the President of Dynamic Solutions, LLC, has successfully built the firm into a national leader in multidimensional modeling, visualizations, and programming engineering.  In 1996 she founded Dynamic Solutions, hiring senior-level engineers and associates with prior work experience to shape the firm’s strategies, structure, and performance with the objective of providing advanced computer modeling, water resource engineering, and uncompromising service.  Ms. Wallen provides leadership for the firm and manages all accounting and financial concerns, overseeing business development, marketing, contractual commitments, human resources and administrative affairs.  Ms. Wallen has over 40 years of professional experience providing support to multidisciplinary engineering projects for the Federal Government, States agencies, and private sectors.  She has extensive consulting experience with USDOE, USEPA and USACE projects and has performed management functions on projects requiring hydrologic, hydrodynamic and sediment transport modeling studies, data analysis and reporting.  Serving as the Contract Administrator, she has full responsibility for successful contract completion, including negotiating with third parties, conducting performance assessments, and evaluating budgets and bids.

Ms. Wallen has specialized experience in operational readiness for environmental remediation projects at Department of Energy (DOE) sites. She has provided support to DOE Environmental Management contractors during the preparation, planning, and execution of radiological and nuclear activities, relating to site mobilization, construction and operations of facilities or process systems.  By integrating the criteria of readiness in the early stages of project planning, she has provided detailed project scheduling of activities cross-referenced to management prerequisites, and continues to maintain the progress of the various disciplines’ objectives to determine critical path.  With a Mechanical Engineering degree, Ms. Wallen has particular expertise in Piping Design and Analysis; Process Flow; Conceptual and Detailed Design; Systems Engineering; Mechanical Integrity Programs, and Procedural Documentation.

Christopher M. Wallen, MS, PG 
​Vice President and Principal

Mr. Wallen is a principal owner and operator of Dynamic Solution, LLC, a nationally known coastal and water resources consulting engineering firm that specializes in hydraulics, watershed hydrology and multi-dimensional modeling of hydrodynamics, sediment transport, water quality, contaminant transport/fate, fisheries and aquatic ecology.  He is a registered Professional Geologist and environmental engineer with over 35 years of consulting experience in surface water modeling to support assessments of hydrodynamics, sedimentation, nutrients, eutrophication, hypoxia, sediment bed remediation, flooding, coastal inundation and sea level rise, Minimum Flows and Levels (MFLs), NPDES Permits, Total Maximum Daily Loads (TMDLs), thermal impact, environmental investigations, and litigation support.
Mr. Wallen has directed hydrodynamic, sediment transport, water quality, and contaminant fate modeling studies in over 25 states on some of the largest and most complex waterways in the nation including Newark Bay/Lower Passaic River, Housatonic River, Lower Fox River, Columbia/Willamette Rivers and Portland Harbor, Kalamazoo River, Ohio River, Mississippi River, Illinois River, Sacramento San Joaquin Delta, embayments of the Louisiana Gulf Coast, and the Everglades. His involvement in high-profile surface water modeling projects and remedial investigations includes design of the modeling and investigational approach, data collection/analysis, coordination and management of multidisciplinary engineering scientific teams, quality assurance, and coordination and negotiations with regulatory agencies and Stakeholders.
He has supported litigation as an expert witness for a number of high profile environmental compliance and navigation cases throughout the United States. He has managed sediment bed contamination projects in industrial waterways, including the Housatonic River, Lower Fox River, Kalamazoo River, Columbia-Willamette River/Portland Harbor, and Newark Bay/Lower Passaic River, to support Superfund Site litigation cases to determine cleanup strategies and apportionment of liability for remediation of contaminants and cleanup costs among Principal Responsible Parties.  He has directed litigation cases and served as an expert witness for inland waterways, including the Lower Mississippi River, the Illinois River, and the Ohio River, related to barge accidents and bridge failure from scour/sedimentation in navigable waterways. He has supported litigation for an interstate water dispute where he directed assessments of the impact of river inflow and sea level rise on coastal inundation, salinity intrusion, nutrients, and decline of shellfish and fishery resources in Apalachicola Bay in Florida.  In support of CWA litigation involving an NPDES permitted industrial discharge, he provided expert witness testimony to present an assessment of the impact of the wastewater discharge on compliance with water quality standards and the occurrence of a large fish kill in the Ogeechee River in Georgia.
Mr. Wallen has expertise in the following capabilities:  Litigation Support and Expert Witness ♦ Hydraulic/Hydrologic Watershed Modeling ♦ Groundwater Modeling ♦ Hydrodynamic Modeling ♦ Sediment Transport Modeling ♦ Contaminant Fate Modeling ♦ Water Quality Modeling ♦ Client Representation at Public Meetings ♦ Project Management ♦ Minimum Flows and Levels ♦ NPDES Permits and TMDL development

Andrew Stoddard, PhD
​​Senior Environmental Engineer

Dr. Stoddard is a Senior Environmental Engineer with national recognition as an expert in surface water quality analysis and modeling of rivers, lakes, estuaries and coastal waters. He has been working with Dynamic Solutions, LLC since 2002 and his 50+ years of government, academic and consulting experience includes field data collection on oceanographic cruises and assessments of physical and biogeochemical processes that control nutrient enrichment, eutrophication, Harmful Algal Blooms (HABs), and hypoxia/anoxia.  In projects performed for EPA, USACE, NOAA, USGS, and State/local agencies, he has applied his expertise to support water resource, water supply assessments, water quality management, and environmental policy/regulatory assessments including waste load allocations, NPDES permits, Total Maximum Daily Load (TMDL), and Numeric Nutrient Criteria (NNC) studies.
He has extensive experience compiling large historical data bases from secondary data sources and he has developed innovative data integration approaches to support statistical analyses based on seasonal and hydrologic filtering rules to extract signals from the noise of large databases.  Applications of his Signal Detection Approach include assessments of Clean Water Act (CWA) effluent regulation policies on long-term water quality trends; wind forcing and upwelling on algal blooms and coastal hypoxia; and Lower Mississippi River diversion projects on salinity intrusion, nutrient/sediment removal and occurrence of algal blooms. The CWA study earned recognition from EPA’s Office of Water as being “the first national-scale study to provide a rigorous evaluation of the effectiveness of the effluent regulation policies in achieving the ‘fishable and swimmable’ goals of the CWA.”
He is an expert in the use of public domain models (EFDC, WASP and QUAL2K) and his projects include assessments of salinity, nutrients, dissolved oxygen, eutrophication and contaminants in freshwater and coastal-estuarine waterbodies such as water supply reservoirs in Oklahoma, the Kansas River, the Lower Fox River (WI), Sacramento-San Joaquin Delta (CA), Apalachicola Bay, Indian River Lagoon and the Caloosahatchee River Estuary in Florida and Peconic Bay (NY) and the Middle Atlantic Bight (NY-NJ).
Dr. Stoddard has performed modeling evaluations for system-wide eutrophication modeling efforts including NYC DEP Long Island Sound Technical Advisory Committee and USACE Waterways Experiment Station New York Bight Feasibility Study and he has served as a Model Evaluation Group Member for NJ DEP’s Barnegat Bay – Little Egg Harbor Estuary Eutrophication Model.  Dr. Stoddard was appointed in 2003 as a part-time lecturer in the Whiting School of Engineering, Engineering for Professionals Program of Johns Hopkins University.
Dr. Stoddard has expertise in the following capabilities: Hydrodynamics, Sediment Transport, Chemical Fate and Water Quality-Eutrophication Modeling |BASINS/HSPF, EFDC, WASP, QUAL2K | TMDLs and Waste Load Allocations | Numeric Nutrient Criteria | Water Quality Based Effluent Limits | Statistical Analyses of Water Quality Trends | Independent Peer Review | Litigation Support.

William McAnally, PhD, PE, D.CE, D.NE, F. ASCE
​Senior Water Resources Engineer

Dr. McAnally is a nationally recognized coastal engineering, sediment transport and navigation expert with 50+ years of professional experience. His experience includes 33 years with USACE Coastal and Hydraulics Lab, Engineer R&D Center performing and supervising hydraulics, sedimentation, and waterborne transportation studies. He served as Technical Director for all USACE navigation-related research. He taught water resources engineering at Mississippi State University for 12 years and holds an Emeritus Research Professor position there. He is a registered professional engineer in Mississippi and Diplomate in coastal engineering and in navigation engineering. He has performed and led numerous successful projects involving riverine and waterways design and environmental enhancement and testified as an expert witness. He has authored more than 200 publications, including a chapter in the American Society of Civil Engineers Sedimentation Engineering Manual 110. Dr. McAnally has particular expertise in the following capabilities: Hydraulic Modeling | Hydrodynamic Modeling | Sediment Transport Analysis and Modeling | Coastal and Inland Navigation Studies | Model and Software Development

Silong Lu, PhD, PE, D.WRE
​Principal Water Resources Engineer and Hydrologist

​Dr. Lu has 35 years of research and consulting experience in groundwater hydrology, watershed hydrology, surface water and coastal hydraulics and hydrodynamics. His expertise includes groundwater flow, fate and transport and density-dependent saltwater intrusion modeling; watershed and hydraulic modeling; surface and groundwater interaction; hydrodynamic, sediment and water quality modeling of rivers, lakes, wetlands and estuaries; coastal tide and wave analysis and modeling; water resources planning and management; hydraulic structure design and physical model construction and testing; hydrologic and hydrogeologic data collection, evaluation and analysis; and computer and GIS programming. Dr. Lu has conducted QA/QC and served as technical reviewer, technical lead, project lead and project manager on numerous projects. He also served as a peer reviewer for Water Resources Research, Journal of American Water Resources Association, and Transport in Porous Media. Dr. Lu has mastered numerous watershed, surface water and groundwater models including MODFLOW, MT3D, SEAWAT, MODPATH, WASH3D, VLEACH, HEC-1, HEC-2, HEC-HMS, HEC-RAS, EPD-RIV1, EFDC, WASP, TR-66, LSPC/HSPF, SWMM, MIKE SHE, MIKE HYRO RIVER and WAM, and possesses working knowledge of STWAVE, ADCIRC, SWAN, and RMA2.

​Shaye Sable, PhD 
​Senior Aquatic Biologist/Ecological Modeler

​Dr. Sable is an aquatic/fisheries biologist and ecological modeler with extensive experience developing and applying population, community, and food web models to evaluate population and ecosystem responses to changing environmental conditions, habitat, and stressors such as invasive species and exposure to toxicants.  She has linked her models to time series of environmental data, hydrodynamic models and water quality models to explore how aquatic populations and food webs respond to freshwater river diversions, hypoxia and contaminants, habitat restoration and degradation.  Dr. Sable has developed statistical analyses and models to describe long-term environmental and biological data, as well as complex, process-based ecological models of aquatic species and ecosystems throughout the U.S., with most of her work along the Louisiana coast.  Dr. Sable has provided scientific guidance, expert opinions, data analyses and review, as well as numerical modeling for operations and alternatives analyses, in order to support federal and state project teams on Biological Assessments, Environmental Assessments and Environmental Impact Statements, Management and Adaptive Management Plans related to freshwater and sediment diversions, oyster reef and wetland restoration projects, water resource projects and oil spill damage assessment.  She serves as an expert panel reviewer for the U.S. Army Corps of Engineers and supports litigation involving ecological impacts determination and aquatic assessments of water resource, restoration and protection projects.

Zhijun Liu, PhD
​Environmental Scientist and Modeler

Dr. Liu has 20 years of research and consulting experience in watershed hydrology and water quality, and coastal hydrodynamics and water quality modeling of rivers, lakes, and estuaries. He has a Ph.D. in agronomy, M.S. in ecology, B.S. in forestry, and a minor degree in civil and environmental engineering. He is highly experienced with many watershed, hydraulic/hydrodynamic sediment transport, and water quality models including HSPF, EFDC, WASP, QUA2K, SWMM, and HEC-RAS. He has served as reviewers for Journal of the American Water Resources Association, Journal of Environmental Management, Environment Monitoring and Assessment, Journal of Environmental Science and Health Part A Toxic/Hazardous Substance & Environmental Engineering, Journal of Coastal Research, and Journal Scientia Agricola.

Steve Sanborn, MS, PE
Senior Water Resources Engineer

​Mr. Sanborn is a Water Resources Engineer with 22 years experience performing a wide range of river and estuarine studies throughout the USA.  He has a Master’s Degree in civil engineering, focused on the intersection of hydraulics, geomorphology, and ecology. Mr. Sanborn is a registered professional engineer in the states of Louisiana, Tennessee, and Oklahoma. Steve has extensive experience developing hydrodynamic models using the USACE’s advanced multidimensional hydrodynamic and sediment transport model the Adaptive Hydraulic (ADH) model, performing hydro-geomorphic studies, sediment transport analyses, river surveys, literature reviews, and ecosystem restoration studies.  Additionally, Steve has been the lead instructor for many ADH hydrodynamic and sediment transport model training courses.

Timothy Stephens, PhD, PE
​Water Resources Engineer

Dr. Stephens is a water resources engineer with extensive experience working on a wide array of projects related to rivers, floodplains, coasts. He is a registered professional Engineer in the state of Tennessee, and his expertise includes hydrodynamic modeling, flood risk analysis, environmental restoration and design, natural and nature based features, sediment transport modeling, coastal flood modeling, preparation of construction plans and drawings, and conducting river surveys and water quality sampling. Dr. Stephens has collaborated with state and federal agencies on ecosystem impact studies. He has conducted and published peer reviewed research on fish passage, compound flooding, hydrologic trends, and flood risk analysis. Dr. Stephens has developed an innovative tool and modeling framework for quantifying the uncertainty and reliability of flood protection during historic, current, and future climate and land use scenarios. 

Shuvashish Roy, MS, PE
Water Resources Engineer