USGS Groundwater Information
New & Noteworthy
USGS Groundwater Watch
USGS maintains a network of active wells to provide basic statistics about groundwater levels.
USGS in Your State
USGS Water Science Centers are located in each state.
Other USGS Water Science Areas
FLASH: A Computer Program for Flow-Log Analysis of Single Holes
FLASH (Flow-Log Analysis of Single Holes) is a computer program for the analysis of borehole vertical flow logs. The code is based on an analytical solution for steady-state multi-layer radial flow to a borehole. The code includes options for (1) discrete fractures and (2) multi-layer aquifers. Given vertical flow profiles collected under both ambient and stressed (pumping or injection) conditions, the user can estimate fracture (or layer) transmissivities and far-field hydraulic heads. FLASH is coded in Microsoft Excel with Visual Basic for Applications routines. The code supports manual and automated model calibration.
First official release is version 1.0, released March 7, 2011. FLASH v1.0 has been tested for use with Microsoft Excel 2007 with Visual Basic for Applications routines
Source Code and Documentation
Day-Lewis, F.D., Johnson, C. D., Paillet, F.L., and Halford, K.J, 2011, FLASH: A Computer Program for Flow-Log Analysis of Single Holes v1.0: U.S. Geological Survey Software Release, 07 March 2011, http://dx.doi.org/10.5066/F7319SZC.
Point of Contact
Support is provided for correcting bugs and clarification of how FLASH is intended to work. Only limited assistance can be provided for applying FLASH to specific problems by contacting the point of contact listed below:
Other USGS Groundwater Software
The USGS develops groundwater , water-quality, surface-water, and other water-resources software for use by the USGS in fulfilling its mission. Most of this software is available online for download at no charge.
Disclaimers and Notices
Please refer to the USGS Water Resources Software User Rights Notice for complete use, copyright, and distribution information. This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Note: Some or all of this information is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of the free Adobe Reader from the Adobe web site. Visit http://www.adobe.com/accessibility/ for free tools that allow visually impaired users to read PDF files.