Groundwater Modeling Software Development
  
SSP&A is known for the significant role it has played in the development of groundwater modeling software.

The most widely used groundwater contaminant transport model, MT3D, was developed by staff of SSP&A and is presently marketed worldwide. The versatile particle-tracking model, PATH3D, was also developed by SSP&A staff and its development continues. Steven Larson, SSP&A Executive Vice President, was a co-author of the U. S. Geological Survey's groundwater flow model, "Finite-Difference Model for Simulation of Three-Dimensional Groundwater Flow." SSP&A staff also authored the textbook "Applied Contaminant Transport Modeling – Theory and Practice" which can be purchased with educational versions of SSP&A’s popular groundwater flow and transport software. Recently, SSP&A has collaborated with the USEPA to develop programs extending the simulation capabilities of MT3DMS Version 5, and with the USGS to develop programs for analyzing the uncertainty in numerical models with a focus on MODFLOW-2000.