Liquid High Consequence Area (HCA) Analysis Support
Client: Hazardous Liquid Pipeline Operator With PHMSA-Regulated Pipeline Assets
CHALLENGE:
A hazardous liquid pipeline operator required a defensible and repeatable High Consequence Area (HCA) analysis to support compliance with 49 CFR Part 195 Subpart F and associated integrity management requirements. The operator needed to identify and document worst-case discharge scenarios, associated spill pathways and HCA impacts across multiple pipeline segments. Existing third-party HCA studies often emphasized release volume alone, provided limited transparency into spill pathway extent and required extended turnaround times that made updates difficult when pipeline data, valve configurations or HCA layers changed. The operator required an analysis approach that could be efficiently re-run, spatially explicit and suitable for regulatory review.
SOLUTION:
Altamira developed and applied a custom Liquid HCA Analysis Tool that integrates pipeline system attributes, terrain, hydrography and HCA datasets into a single, automated GIS-based workflow. The tool evaluates each potential release location independently and produces consistent, regulator-ready outputs that document both worst-case discharge and downstream consequence.
As part of the Liquid HCA Analysis, Altamira performs the following activities:
- Validation and preparation of pipeline centerline geometry, valve locations, segmentation and stationing to ensure accurate isolation limits and spatial consistency
- Automated generation of potential spill locations along pipeline segments based on operator-defined criteria
- Calculation of worst-case discharge volumes for each spill scenario using segment-specific isolation limits and pipeline geometry
- Terrain-informed modeling of overland flow and surface drainage to represent potential spill migration
- In-channel transport modeling along mapped hydrography to evaluate downstream exposure pathways
- Explicit calculation of the Length of Worst-Case Discharge, documenting the maximum spatial extent of potential impact in addition to volume
- Spatial intersection of modeled spill pathways with applicable HCA datasets, including populated areas, drinking water resources, environmentally sensitive areas and navigable waterways
- Compilation of tabular summaries, figures and maps suitable for integrity management documentation and regulatory review
This analysis is performed programmatically, allowing results to be reproduced and efficiently updated as pipeline system data or HCA layers change.
RESULTS:
Altamira delivered a repeatable and defensible Liquid HCA analysis framework that improves transparency and efficiency compared to traditional approaches. The analysis provides clear documentation of worst-case discharge volume and associated impact length, supporting integrity management decision-making and regulatory compliance. The automated workflow reduced overall analysis turnaround time by approximately 50 percent compared to typical third-party Liquid HCA studies, enabling faster updates and re-analysis when system conditions change. The resulting maps, tables and summaries are suitable for ongoing integrity management use, audits and PHMSA review.
