What is GFLOW?
GFLOW is a highly efficient stepwise groundwater flow modeling system developed by Haitjema, LLC. GFLOW is a Windows program based on the analytic element method. It models steady state flow in a single heterogeneous aquifer using the Dupuit-Forchheimer approximation. While GFLOW supports some local transient and three-dimensional flow modeling, it is particularly suitable for modeling steady-state regional flow. To facilitate detailed local flow modeling, GFLOW supports a MODFLOW-extract option to automatically generate MODFLOW files in a user defined area with aquifer properties and boundary conditions provided by the GFLOW analytic element model.
How to Acquire GFLOW
You may download GFLOW from the EPA website:
Click on the image for more screenshots of GFLOW
GFLOW supports conjunctive groundwater - surface water solutions. In the image, the pumping rates of several wells near a small stream have been doubled. As a result parts of the stream stopped flowing.

Additional screenshots are available in the Screenshot Gallery.

Analytic Element Modeling of Groundwater Flow (free)
Analytic Element Modeling of Groundwater Flow

Click here to obtain the book "Analytic Element Modeling of Groundwater Flow" by Henk Haitjema for free.