Halford Hydrology LLC is just me, Keith Halford, a groundwater hydrologist with a bent for pragmatically answering questions. Aquifer-test analysis, development of groundwater-flow models, and programming for hydrologic applications are my areas of expertise. I have developed techniques for integrated interpretation of multiple, multi-well aquifer tests (Halford, 1997; Halford and Yobbi, 2006; Garcia and others, 2017). I have developed and published methods for directly comparing transmissivity estimates from aquifer tests to simulated transmissivities in groundwater-flow models (Halford, 2016). Site-specific calibration has been emphasized because transmissivities greatly vary and are the most reliable hydraulic property estimated at field-scale (Halford and others, 2006).
Tools for hydrologic analysis that I have developed can be downloaded from this site. Most of these tools are Microsoft Excel workbooks or add-ins. Published examples are workbooks for analyzing single-well aquifer tests (Halford and Kuniansky, 2002) and flow logs (Halford, 2009; Day-Lewis, 2011). SeriesSEE is an Excel add-in for time-series and flow-log analysis that supports water-level modeling to identify drawdowns smaller than natural water-level fluctuations (Halford and others, 2012). Many informal tools and techniques were posted previously under Excel for Hydrology.
I continue to develop applications for hydrologic analysis by revising dated approaches and visualizing model output in Google Earth. For example, fitting lines in charts were moved directly in the Halford and Kuniansky (2002) workbooks. This approach was negated after Excel 2007 and replaced with new methods. Visualizing results have been expanded to mapping in Google Earth as with the Piper-Stiff workbook. These applications are listed on the Tools page.