SSP&A has developed modeling and related software for over 20 years.

SSP&A develops and distributes software for groundwater modeling and related analyses. Many of these programs are provided free-of-charge, although a professional version of MT3D, referred to as MT3D99, is available. Select a software offering below to learn more.

GroundWater Desktop

Groundwater Desktop (GWD) is a fully 3D interface for visualizing groundwater models and their results. While GWD is flexible and might be used to visualize any model, development to-date has focused on MODFLOW, MODPATH, and MT3D, including the latest unstructured grid capabilities within MODFLOW-USG. GWD enables users to view the model numerical grid, input data such as properties and boundary conditions, and output data including heads, concentration, and pathlines. Models can be examined using cross-sectional, cut-away, and layer "exploded" views. 


ATRANS A 3D analytical solution for transport from a patch boundary condition with time varying concentration.


MT3D99 - The Leading Code for Analyzing Contaminant Migration in Groundwater.


PATH3D V4.6 is a powerful and widely used particle-tracking program for MODFLOW.


MPNE1D A General Analytical Solution for One-Dimensional Solute Transport. MPNE1D is a FORTRAN90 code that implements the general analytical solution for one-dimensional solute transport.


BIOSCREEN-AT is a screening-level model developed for and distributed by the EPA that simulates remediation through natural attenuation of dissolved hydrocarbons at petroleum fuel release sites.


PEST - the world’s most advanced software for model calibration, parameter estimation and predictive uncertainty analysis. The days of manual model calibration and data interpretation are over.


KT3D_H2O Version 3.0 - A Program for Kriging Water Level Data using Hydrologic Drift Terms.


A Source Screening Module (SSM) has been developed in MS Excel to support preliminary evaluation of the threat posed by vadose zone waste sites on groundwater quality.

Applied Contaminant Transport

Applied Contaminant Transport Modeling Theory and Practice - Textbook


S.S. Papadopulos and Assoc. Inc., in collaboration with the University of Waterloo, has developed the most powerful particle tracking program for MODFLOW and MODFLOW-USG.


OneD - Excel implementation of analytical solutions for one-dimensional transport of solutes in groundwater.


DECAY is an analytical solution for one-dimensional transport of multiple species along a decay chain with branching. The treatment of branching accommodates species potentially having more than one parent and species having more than one daughter product. The DECAY solution considers advection, dispersion, equilibrium sorption, and first-order straight-chain and branching decay reactions. The species may have different dispersion and sorption coefficients. The solution accommodates the specification of different decay rates for the dissolved and sorbed phases for each species.

US Locations

International Locations