Modeling and Optimization

Management Strategies for a Sustainable Future – HGL is a leader in modeling groundwater and surface water to visualize and predict contaminant transport, estimate cleanup time frames, and manage water resources. Modeling is a valuable tool that allows designers and engineers to understand the behavior of a dynamic system and support technical and managerial decision-making. HGL’s modelers have in-depth experience in building models that meet user needs and provide the output necessary to develop solutions to complex environmental and resource management challenges.

Groundwater/Surface Water Modeling: HGL has successfully developed and applied industry standard modeling software and decision support tools (MODFLOW-SURFACTTM and MODHMS®) to solve environmental restoration and water resources management problems. Services include the following:

  • Hydrogeologic Investigations
  • Groundwater/Surface Water Interaction Modeling
  • Multimedia Flow and Transport Modeling
  • Watershed Evaluation
  • Water Resource Planning

Physics-Based Management Optimization (PBMOTM): PBMOTM links advanced optimization algorithms with site flow and transport models and integrates multiple variables and constraints into the decision process at a level of detail previously considered impractical. For each site, HGL considers the conceptual site model (CSM), the goals of the remedy, available data, remedy performance, protectiveness, cost-effectiveness, and closure strategy. PBMO features include the following:

  • Optimal solutions for multiple remedial objectives
  • Distributed computing (Cloud)
  • Linkage to MODFLOW-MT3D and MODFLOW-SURFACTTM
  • Optimized remedial design
  • Water resource management

Products: HGL has a wide array of innovative tools for modeling, data management, and environmental remediation and water resource management optimization. For more information about the following, please contact info@hgl.com.

Training: Whether a novice or an experienced user of HGL’s codes, HGL offers courses that will enable users to build expertise and increase productivity. HGL offers tailored modular courses, as well as open-schedule, customized seminars to government agencies, regional and local water management agencies, research institutions and universities, consulting firms, and engineering companies in the United States and abroad. To find out which training option best meets your needs, please contact info@hgl.com to request a free training consultation.
The following projects demonstrate HGL’s expertise with modeling/optimization:

Modeling

Optimization

 

Peace River Integrated Modeling Project, Florida

For the Southwest Florida Water Management District (SWFWMD), HGL developed and calibrated an integrated groundwater/surface water model of the 2,350-square-mile Peace River basin in west-central Florida. The Peace River basin is the largest watershed in the SWFWMD jurisdiction, and it has been significantly affected by activities such as residential construction, farming, and phosphate mining. These activities have changed the natural hydrology of the basin, altering drainage patterns and lowering the groundwater potentiometric surface. A steady, long-term decline in stream flows has occurred since the early 1960s.
Through this project, HGL assisted the SWFWMD in implementing a recovery strategy to restore basin storage and increase aquifer recharge to mitigate the effects of groundwater withdrawals for water supply. The model calibration encompassed stream flows, lake levels, and groundwater potentiometric heads. In follow-up work, HGL simulated the effects of various alterations that had occurred in the basin as a result of human activities and assessed management alternatives to restore flows in the Peace River, including adjusting groundwater withdrawals, creating surface water storage areas in the upper part of the basin, and constructing rain gardens to enhance infiltration.

Project Highlights
Developed a conceptual hydrological and regional hydrogeological model, including the roles of Karst sinkhole features, lakes, and streams on groundwater/ surface water interactions.
Developed local and regional groundwater and surface water budgets.
Prepared and calibrated a transient integrated groundwater/surface water model.
Performed model sensitivity analyses and simulated select future land use and management scenarios, including changes in groundwater pumping.
Trained SWFWMD personnel on use of the model.

 

Simulation of Water Flow and Phosphorus Transport in a Highly Interactive Surface Water/ Groundwater System in the Everglades National Park, Florida

For the Everglades National Park (ENP), HGL developed a MODHMS®-based model of surface and subsurface water interaction to analyze the flow and transport of phosphorous in an area along the southeastern boundary of the ENP. The model was prepared to support the development of the marsh-driven operations plan, which is an aspect of the Comprehensive Everglades Restoration Plan. The fully integrated surface water/groundwater flow and transport model served as an analytical tool to investigate the effects that the construction of levees, canals, pumping stations, and detention basins had on groundwater flow and water quality. The goal of the project was to evaluate how nutrients from agricultural areas outside of the ENP could have affected the park’s ecosystem and to ensure that water levels and flows in basins and drainage canals were maintained to minimize seepage into the ENP. The developed model simulated transient surface water/groundwater flow and transport in double-porosity porous media for the southeastern boundary area of the ENP in response to the operations of the system of canals, levees, and pumping stations, as well as climatic conditions. This model covered an area of more than 400 square kilometers and was calibrated to a set of pre-specified calibration criteria.

Project Highlights
Developed and calibrated an integrated surface water/groundwater flow and transport model for phosphorus in a highly interactive hydrological system.
Used available data for total phosphorus concentrations, potentiometric elevations, canal and detention basin stages, and flow rates through canals between 2000 and 2007 as quantitative calibration targets.
Evaluated marsh-driven operational plan design and effectiveness.
Identified an operational procedure to achieve hydraulic and ecological objectives.

 

Innovative Approach for Implementing Performance-Based Remediation Project for Optimization of Groundwater Remedial Design and Operation, Former Fort Ord, California

HGL optimized the design and operation of a groundwater remedial system at the former Fort Ord. As a result, the remedial goals for the site were met 3 years before the date estimated in the record of decision (ROD).
HGL employed an integrated approach to address the technical and management complexities, which included the discovery that the plume had extended off site approximately 1,400 feet beyond the previously estimated limit of 2,400 feet, the need to expand the existing remedial system, the presence of an adjacent carbon tetrachloride plume, and existence of critical habitat. The integrated technical approach included the use of groundwater models, a cloud-based parallelized computational optimization methodology that used HGL’s Physics-Based Management Optimization (PBMOTM) tool, the ongoing adjustment of pumping schedules based on performance monitoring, and construction practices that minimized impacts on habitat. HGL achieved the groundwater remedial actions objectives in 2014, completed attainment monitoring in 2015, and obtained remedial action-completion concurrence from California regulatory agencies in 2016.
In April 2017, the American Academy of Environmental Engineers & Scientists® (AAEES) awarded HGL a grand prize for its work at the former Fort Ord. The Excellence in Environmental Engineering and Science competition award was received in the category for research, planning, design, or operations/management projects.

Project Highlights
Recalibrated the groundwater flow and transport model developed during the remedial design phase to simulate the migration of TCE.
Used a groundwater model in conjunction with PBMOTM to evaluate alternative pumping strategies, including varied extraction rates and continual versus intermittent pumping at any combination of wells.
Conducted PBMOTM simulations that provided the basis for developing an optimized exit strategy that ensured that cleanup goals would be met in the most cost-effective manner and within the time period envisioned in the ROD.

 

Dewatering Optimization at a Proposed Iron Mine Site in Western Australia

HGL provided an optimal design for a dewatering program at an open-pit mine in the Pilbara region of Western Australia. HGL deployed its Physics-Based Management Optimization (PBMOTM) system to optimize the mine dewatering program for a lens in the middle of the mining area and compared the results to the subjective engineering judgment developed solution. Locations for candidate extraction wells and exclusion zones were provided to HGL. In total, 113 wells, comprising 100 ex-pit wells and 13 in-pit wells, were supplied as candidate wells for PBMOTM to optimize. The ex-pit wells were scheduled to begin operating before mining operations extended below the water table, and the in-pit wells were scheduled to be activated after 4 years of mining, when those well locations would be available and accessible. The dewatering strategy developed using subjective engineering judgment would have required using 26 extraction wells to meet the mining schedule. However, the PBMOTM optimal design required use of only 17 individual wells, with no more than 11 extraction wells operating at any one time.

Project Highlights
Used a MODFLOW-SURFACTTM variably saturated, mass conserving calibrated flow model combined with the PBMOTM global optimal search strategy to determine an optimal dewatering program.
Realized the following benefits by using the PBMOTM design rather than the subjective engineering design:

  • A significant reduction in peak flow rates and total volume of water extracted, resulting in an estimated savings of $4.6 million.
  • Compliance of all extraction well locations with restrictions on well placement.
  • Compliance of all groundwater levels with mine schedule requirements.

 

 

 

Point of Contact

Dua Guvanasen, Ph.D., PE
Vice President
E-mail: dguvanasen@hgl.com