Transformed Distance-Drawdown Method Spreadsheet and Program
HydroQual is pleased to announce the release of a spreadsheet (TDDMSS) and associated computer code (TDDM) to automate the transformed distance-drawdown method developed by Robert Mutch of HydroQual (Mutch, 2005) The spreadsheet and program are both available for download to interested users by registering through HydroQual's website. The software will be distributed only to registered users so that we can provide upgrades, "bug fixes", etc. to users without delay. HydroQual reserves the right to limit distribution of TDDMSS and TDDM at its sole discretion. Follow the link below to download the latest version of TDDMSS and TDDM.

Brief Description
TDDMSS and TDDM were developed to support the analysis of fractured rock aquifer test data using the Transformed Distance-Drawdown Method. This method is the first distance-drawdown technique developed for areally anisotropic aquifers. The method uses scalar transformation to convert an areally anisotropic medium to an equivalent, isotropic medium, thus permitting application of the Cooper-Jacob Method. A least squares regression approach is employed to estimate the orientation and magnitude of the anisotropy. The regression R² value provides a quantitative assessment of the degree to which the drawdown data are indicative of a systematic areal anisotropy in the aquifer or whether the data simply reflect natural aquifer heterogeneity. In addition to confined aquifers, this methodology, like the Cooper-Jacob Method, is also applicable to unconfined aquifers either before the onset of delayed drainage or following the completion of delayed drainage provided that the u value meets the recommended criterion.

Registration and Downloads
TDDMSS and TDDM are available for download at no cost. If you wish to download the TDDMSS spreadsheet and the TDDM code, please register here and you will be sent a login name and password by e-mail.

Please Note!    If you use browsers other than Microsoft Internet Explorer you may not be able to download files from this site. Please contact it@hydroqual.com in those cases.

If you have already registered and received your login name and password, login here.

Additional Information
To report problems and provide feedback, please contact it@hydroqual.com.

Reference
Mutch, R. 2005. A Distance-Drawdown Aquifer Test Method for Aquifers with Areal Anisotropy. Ground Water 43, No. 6:935-938.

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