Recent News: "MODFLOW" Models for Download Groundwater flow within the Cambrian-Ordovician and Lower Dakota aquifers were modeled using Visual MODFLOW version 2009.1. In order to run the models on a local PC, compressed (.zip) files were created and placed on the Iowa DNR's FTP website for public consumption. Before downloading a compressed (.zip) file, please open the associated "README" file (.txt) to learn more about the selected model. To access these files, click here.