February 7, 2011


SUBJECT: PROGRAMS AND PLANS—Groundwater Flow and Transport Model Archival

Groundwater models are often an integral part of U.S. Geological Survey (USGS) investigations and the conclusions published in USGS reports often are based on results of these models. As a result, several Office of Groundwater (OGW) policy memorandums have given guidance and requirements for documentation and archival of groundwater flow and transport models. We list four of these memorandums at the end of this memo. The primary purpose of this memorandum is to update the policy for model archival.

All groundwater flow and transport models that are a significant part of groundwater investigations must be archived as specified in Office of Groundwater (OGW) Technical Memorandum 00.02 (http://water.usgs.gov/admin/memo/GW/gw00.02.html). The Water Science Field Team (WSFT) Groundwater Specialists act on behalf of the Office of Groundwater to assure that all required information is present in the archive and to verify compliance with the policy. This policy continues as before with two additions effective for models with completion dates of March 2011 or later.

One addition to the policy is that the general boundaries of the model (the latitude and longitude of the corners of a rectangle outlining the model grid area) should be included in a text file (filename: modelgeoref.txt) that contains the georeferencing information and is filed at the upper level directory of that particular model archive. This will document the area under study and allow for future map displays of the availability of models developed by the USGS.

The second addition to the policy is that all reports that contain groundwater flow and transport models must have their model archive reviewed and approved by the WSFT Groundwater Specialist before the report is submitted to the Bureau Approving Official for approval. This requirement has been in place in the former Northeast and Southeast Regions for some years and is now extended nationwide, as discussed further below.

There has been increased interest in obtaining models from the model archives by public and private entities. Many of our cooperators run our archived models. With greater use, it is increasingly important that the archives exist and can duplicate information in our published reports. Technical reviews of the Water Science Centers (WSC) have found model archives sometimes are insufficient to duplicate the model results, there is a significant delay in creating the archives, or archives are never completed.

Prior to submission of a groundwater modeling report to the Bureau Approving Official, the WSC Director or their designee (typically the WSC Groundwater Specialist) should review the archive to ensure compliance with OGW Technical Memorandum 00.02. The archived model needs to be run and the output compared with the text, figures, and tables in the report to ensure that the data are comparable. The WSC should then notify the WSFT Groundwater Specialist that the report and archive are available for review. The archive, report, and associated technical reviews should be transmitted to the WSFT Groundwater Specialist who will verify proper archival and ensure compliance with other OGW technical memorandums. The WSFT Groundwater Specialist will notify the originating Center by memorandum whether the archive complies with OGW requirements. After any issues are addressed, the report and associated materials, including documentation of the WSFT Groundwater Specialist review and approval of the archive, can be transmitted to the Bureau Approving Official for final approval.

Memorandums on groundwater flow and transport models:

William M. Alley
Chief, Office of Groundwater

Distribution (bcc): A, B, GS-W WSC Directors, OGW, Regional and Water Science Center Groundwater Specialists, MODFLOW-Developers