Ford Engineers was the principal contractor to the Sacramento District (SPK) of the U.S. Army Corps of Engineers for the Central Valley Hydrology Study (CVHS). This study of flood flows in the Sacramento and San Joaquin river basins required estimation of regulated flow frequency at approximately 200 locations. To do so, we simulated system behavior with hundreds of flood events using HEC-ResSim to model operation of more than 70 reservoirs and HEC-RAS to simulate flow in more than 1,500 miles of channels. Results from the models had to be extracted and further analyzed to produce the frequency estimates. We realized traditional methods for accomplishing this were infeasible; those methods were too slow, too difficult to apply consistently across a large project team, and subject to error.

To complete the analysis, in a cost-effective, consistent, error-free manner, we designed and developed a software application. This application, the Information Processing and Synthesis Tool (IPAST), accomplishes the following:

  • Integrates seamlessly with the simulation models through HEC-DSS, the Corps’ data management system.
  • Manages the big datasets from the hundreds of simulations and hundreds of locations, extracting unregulated flow and volume annual maximums and fitting unregulated flow-frequency curves using state-of-the-art procedures developed by the Corps and the U.S. Geological Survey (USGS).
  • Extracts unregulated and corresponding regulated flows and creates in a consistent manner an unregulated-to-regulated flow transform and a regulated flow-to-stage transform for hundreds of sites in the basins.
  • Computes various statistics from historical volume, flow, and stage records and from extracted simulation results.
  • Allows the user to control the sequence and method of analysis and to view all results in an easy-to-understand graphical user interface (GUI) without using the complex simulation applications directly.

We developed IPAST in the .NET platform, with an underlying SQL Server Compact database. We developed the application with an eye on future expansion as needed by SPK. We prepared detailed documentation, including technical reference documents necessary for review of methods and a white paper. IPAST has been approved through the Corps’ H&H Coastal COP Software validation process for projects within the SPK jurisdiction.

We also developed a companion tool to process IPAST results called the "Advanced Query Tool." This tool, which is a standalone program, allows users to compare model results, event data, and flow- and stage-frequency curves from various IPAST projects in a single location.

You can download IPAST and the Advanced Query Tool here:


In addition, a demonstration project file is below. This demonstration project file and configuration is provided solely for informational purposes regarding how a project file could be configured and is not intended for application to a particular study or analysis.

IPAST Demonstration Project