Tank Release Consequence Modeling and HCA Screening

A major midstream and liquids storage operator needed a more defensible method for evaluating the potential impacts of a catastrophic storage tank release and determining whether a spill could extend beyond secondary containment and affect nearby High Consequence Areas (HCAs). Traditional screening methods, such as fixed-radius buffers, could not adequately account for site-specific factors including topography, drainage pathways, product characteristics or the dynamic behavior of a release as it migrated across the landscape.

The operator also needed to understand both the maximum extent of potential spill coverage during the event and the residual area affected after the release stabilized, as each scenario has different implications for emergency response planning, risk assessment and regulatory decision-making.

The modeled release generated a maximum historical spill footprint of 71.27 acres. Based on the defined release, product and terrain assumptions, the spill extended beyond the facility and reached both a HPA and an OPA. The modeled footprint did not intersect evaluated EcoUSA, DwUSA or CNW datasets.

At the conclusion of the eight-hour simulation, approximately 194,119 barrels remained on the modeled surface. The analysis attributed 47,074 barrels to evaporation and 5,565 barrels to infiltration, providing complete volume accounting throughout the event. By preserving the maximum historical footprint, the study captured areas of temporary product contact, ensuring potential HCA interactions were not overlooked.

The analysis provided the operator with a repeatable, data-driven methodology for evaluating storage tank release consequences. Deliverables, including spill progression maps, mass-balance calculations, HCA screening results and a time-lapse visualization, provided a clear understanding of modeled spill behavior and supported informed decisions related to risk management, emergency response planning and future facility evaluations.