Expert GoldSim Consulting
Over 16 years of applied simulation modeling. My experience ranges from architecture design and hands-on training, to cutting-edge integrations that connect GoldSim with Python, EPA hydraulic solvers, and groundwater engines. You get a licensed PE who has built some of the most complex water resources models in use today.
Interactive Dashboard Output: This is a screen capture of a Reservoir inflow forecast that takes into account the weather forecast with growing uncertainty after the 7-day forecast. Climate data is applied to an integrated snowmelt runoff model with water demands and operational logic for an integrated Monte Carlo simulation to inform operational decisions in real time.
Applied Engineering Mentorship
LWS closes the gap between what GoldSim can do and what your project actually needs. That requires engineering judgment, not just software knowledge. Whether you are starting a model from scratch, troubleshooting an existing one, or pushing GoldSim into new technical territory with external integrations, LWS brings the depth of experience to deliver defensible, production-quality results.
Core Services
Model Architecture & Design Consultation
Sound model design is the single largest determinant of whether a GoldSim model produces reliable, maintainable results, or becomes an opaque box that nobody trusts five years from now. LWS provides high-level architecture review and design direction at any stage of development.
- • Conceptual design and structural layout before any coding begins
- • Review of existing models for logic correctness and best practices
- • Mass balance validation and recursive loop resolution
- • Time-step strategy, numerical stability, and integration scheme selection
- • Probabilistic framework design (uncertainty representation that is defensible)
- • Deliverable and dashboard design for stakeholder communication
GoldSim Training
Fifteen-plus years of teaching GoldSim, ranging from introductory two-day courses to multi-year embedded advisory relationships. Training is engineered around your team's specific domain and model type (not a generic feature walkthrough).
- • Introductory and intermediate courses (in-person or remote)
- • Applied curriculum developed around your system
- • Worked-example models built to your project's conventions
- • Capacity-building programs designed so your team can operate independently
- • One-on-one coaching for advanced projects
Past training clients include municipal utilities, state water agencies, mining consultancies, water resources consultants, and research universities across the US and Canada.
Advanced Modeling & Problem-Solving
Complex systems require more than standard model elements. LWS has designed and debugged models across the full spectrum of GoldSim's capability, including distributed Monte Carlo, stochastic hydrology, PID control logic, and multi-objective optimization frameworks.
- • Stochastic weather generation and SPI-conditioned drought simulation
- • Water rights and prior appropriation allocation logic
- • Mine water balance (TSF geometry, PID control)
- • Multi-reservoir cascade operations and shortage analysis
- • Hydraulic infrastructure optimization
- • Scenario automation, multi-realization data export, and post-processing
Advanced Capabilities: DLL Integrations & Custom Tools
GoldSim's DLL interface opens the door to a world of external computation (Python analytics, EPA hydraulic solvers, groundwater engines, and more). LWS has built production integrations across all of these platforms, and can design, implement, and document the architecture your project requires.
Dynamic Configuration Architecture For all four of the GoldSim integrations below, I built the underlying architecture that eliminates the need to recompile the C++ DLL every time the model interface changes. Inputs, outputs, and logging levels are defined dynamically via an external JSON configuration file, giving end-users maximum flexibility without relying on a compiler.
GSPy (GoldSim Python Interface)
GSPy allows Python scripts to interact with GoldSim models at runtime by reading outputs, writing inputs, and executing arbitrary Python logic as part of a simulation. This unlocks the full scientific Python ecosystem (NumPy, SciPy, Pandas, scikit-learn) from inside a live GoldSim run.
- ▹ Integration architecture design and DLL configuration
- ▹ Python workflow development for data pre/post-processing and analytics
- ▹ Log Pearson Type III flood frequency analysis via GSPy
- ▹ Performance optimization for large-dataset models
GoldSim to EPANET Interface
Connects GoldSim's stochastic simulation engine to EPANET's full hydraulic solver, enabling probabilistic analysis of pressurized distribution networks within a long-range planning or operations model. Supply uncertainty and demand variability flow directly into network hydraulics.
- ▹ DLL bridge design and EPANET API integration
- ▹ Demand-driven vs. pressure-driven simulation coupling
- ▹ Monte Carlo propagation through pipe network responses
- ▹ Water quality scenario analysis under uncertain demand trajectories
GoldSim to EPA SWMM Interface
Integrates EPA SWMM's dynamic storm drain and urban watershed solver with GoldSim's probabilistic and systems-level simulation capability. Drive SWMM with stochastic rainfall ensembles generated in GoldSim and propagate hydraulic results into multi-objective planning frameworks.
- ▹ DLL bridge architecture for SWMM5 API
- ▹ Stochastic rainfall forcing from GoldSim weather generators
- ▹ Return period and risk analysis over SWMM hydraulic outputs
- ▹ Combined sewer overflow and detention basin optimization
GoldSim to MODFLOW Interface
Couples GoldSim's surface water and demand system with MODFLOW groundwater simulation, enabling true conjunctive use modeling, where surface water allocations, aquifer recharge, and pumping interact dynamically within a single probabilistic model framework.
- ▹ GoldSim–MODFLOW DLL coupling architecture
- ▹ Dynamic recharge and ET boundary condition exchange
- ▹ Conjunctive use and banking scenario analysis
- ▹ Groundwater–surface water interaction under stochastic hydrology
DataStream
DataStream is a purpose-built extension for GoldSim that writes simulation output to temporary binary scratch files on disk during a Monte Carlo run. Having originally developed this tool's underlying architecture, I am uniquely positioned to help teams deploy it. By offloading large arrays of time-series data from active memory as the simulation progresses, DataStream dramatically reduces the peak RAM footprint of large-scale probabilistic runs, making it feasible to execute high-replication stochastic analyses on standard hardware.
- ▹ Configurable output selection (write only what you need to disk)
- ▹ Transparent integration with GoldSim's Monte Carlo execution engine
- ▹ Enables thousands of realizations on hardware that would otherwise exhaust memory
- ▹ Scratch files automatically managed with no persistent storage overhead
Domain Expertise
GoldSim is domain-agnostic. However, producing a trustworthy model requires engineering expertise. The structural choices to make yours reliable come from having worked these problems across dozens of client engagements over two decades.
Integrated Water Resources
- • Basin-scale water balance modeling
- • Trans-basin transfer and conveyance
- • Multi-reservoir cascade operations
- • Groundwater–surface water interaction
- • Great Salt Lake integrated modeling (GSLIM)
Water Rights & Allocation
- • Prior appropriation doctrine simulation
- • Virtual account priority-stacking architecture
- • Senior call mechanisms and junior curtailment
- • Colorado River shortage and banking modeling
- • Multi-diversion river routing and depletion
Urban Stormwater & Flood
- • Dynamic EPA SWMM trunk-line flood models
- • Snowmelt-driven urban hydrology
- • Animated HGL and surcharge analysis
- • Capital improvement planning support
- • Multi-objective detention pond optimization
Municipal Demand Forecasting
- • Stochastic demographic growth engines
- • Gaussian Copula inter-sector demand correlation
- • FAO crop coefficient irrigation scheduling
- • Climate adaptation scenario analysis
- • Recycled water and return flow accounting
Mine Water & Environmental
- • Open-pit mine water balance (full cycle)
- • TSF dynamic geometry and cumulative deposition
- • Unsaturated cover flow and infiltration tracking
- • PID-controlled pump rate modulation
- • Markov chain rainfall and hydrologic persistence
Stochastic & Probabilistic Methods
- • WGEN/PrecipGen stochastic weather generation
- • SPI drought superposition methodology
- • Log Pearson Type III flood frequency (USGS B17C)
- • Distributed Monte Carlo processing
- • Bootstrap confidence intervals and K-S testing
Representative Engagements
CAP Service Area Model & JSAM
Central Arizona Project (Phoenix, AZ)
Long-term GoldSim technical advisor for CAP's water demand forecasting and Colorado River shortage analysis. Supported multi-agency modeling (CAP, ADWR, AWBA) and delivered training at professional meetings as CAP's modeling needs evolved with shifting Colorado River policy.
Hawke's Bay Water Allocation Model
Hawke's Bay Regional Council (New Zealand)
Built the complete GoldSim model from scratch for New Zealand's Hawke's Bay Regional Council, the largest single modeling engagement performed during tenure at GoldSim Technology Group. Simulated full water allocation, dam operations, and distribution network for a region with significant agricultural and municipal demands. Supported dam feasibility analysis, independent scientific review (NIWA), and distributed Monte Carlo processing.
Salt Lake Valley Water Balance
Utah Division of Water Resources (collaboration, Salt Lake Valley, UT)
Developed an integrated water resources model of the entire Salt Lake Valley, tracking trans-basin imports from the Provo River, distribution across JVWCD, CUWCD, and Metro Water, groundwater interaction, municipal demand, irrigation canal routing, WWTP return flows, and final outflows to the Great Salt Lake.
Great Salt Lake Integrated Model (GSLIM)
Utah Division of Water Resources (Salt Lake City, UT)
Provided multi-year advanced support on GSLIM, one of the most complex institutional water balance models in the Intermountain West. Advised on model architecture, stochastic hydrology methodology, and scenario design. Delivered formal GoldSim training webinars and coordinated technical support between Utah DWR, Jacobs, and University of Utah researchers.
Calaveras Reservoir Operations Model
San Francisco Public Utilities Commission (San Francisco, CA)
Provided multi-year advanced support to SFPUC engineers on reservoir operations modeling, probabilistic inflow ensembles, and yield and refill analysis under alternative operating strategies. Co-authored conference abstracts and managed GoldSim licensing and distributed processing infrastructure.
City of Santa Fe Climate Adaptation Model
Hazen and Sawyer (New Mexico)
Advanced technical advisory to Hazen and Sawyer on a complex GoldSim model for Santa Fe encompassing supply-demand allocation logic and approximately 30 climate adaptation strategies. Reviewed model architecture, advised on strategy implementation, and supported PowerShell-based scenario automation and multi-realization data export workflows.
MPI Agricultural GHG Emissions Model
Ministry for Primary Industries (Wellington, NZ)
Lead model developer on a formal consultancy engagement to build a prototype agricultural greenhouse gas emissions calculation tool supporting New Zealand's national emissions policy development. Translated official MPI methodology documentation into validated GoldSim execution logic across five livestock categories, validated against MPI benchmark tables, and delivered to the MPI Chief Scientist and CEO.
Ready to Build Something Reliable?
Whether you need a model designed correctly from day one, a struggling model rescued, or a multi-engine integration built from scratch, let's talk.
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