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Software Spotlight/
Chunmiao Zheng/ Software Editor
Introduction
A number of new spreadsheets have been developed by the U.S. Geological Survey (Halford and Kuniansky 2002) for the analysis of aquifer-test and slug-test data, a common task for hydrogeologists and ground water engineers. The spreadsheets are written in Microsoft Excel version 9.0. The spreadsheets, together with a PDF version of the documentation, can be downloaded for free from the USGS Web site (http://water. usgs.gov/pubs/of/of/ofr021971). Users can open a specific spreadsheet (worksheet) within the Excel file. The key features, advantages, and disadvantages of the spreadsheets are briefly reviewed in this column.
Overview of Features
A total of 10 spreadsheets are included in the collection. Six spreadsheets are for processing aquifer-test data. Some commonly used data analysis methods are incorporated, including the Cooper-Jacob straight-line method, Theis recovery data analysis for a confined aquifer, Jacob-- Lohman method for a flowing well in a confined aquifer, step-drawdown methods, distance-drawdown methods, and Hantush-Jacob leaky aquifer method. Three spreadsheets are for processing slug-test data using the Bouwer and Rice method, Cooper-Bredehoeft-Papadopulos method, and van der Kamp method. In addition, one spreadsheet was developed to predict drawdown in a confined aquifer based on the Theis equation. This spreadsheet is not designed to estimate aquifer parameters. It can be used only in forward mode and may be helpful in planning aquifer tests.
All the spreadsheets are designed for single-well tests except for one that is based on the distance-drawdown method for analysis of multiwell test data once the drawdown has reached quasi-steady state. As pointed out in the documentation, use of single-well tests for estimation of storage properties is generally discouraged because single-- well tests are affected by wellbore storage and by well construction. For this reason, all the spreadsheets output the estimated hydraulic conductivity or transmissivity, but storativity is given only in four spreadsheets such as those...