Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Program to Analyze Aquifer Test Data and Check for Validity with the Jacob Method.
Author Field, M. S. ;
CORP Author Environmental Protection Agency, Washington, DC. Office of Research and Development.
Publisher c1993
Year Published 1993
Report Number EPA/600/J-93/127 ;OHEA-E-493;
Stock Number PB93-181154
Additional Subjects Aquifers ; Water pollution monitoring ; Aquifer testing ; Computer programs ; Computerized simulation ; Hydrogeology ; Drawdown ; Transmissivity ; Storage coefficient ; Fluid flow ; Reprints ; Jacob Straight-Line Method
Library Call Number Additional Info Location Last
NTIS  PB93-181154 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 08/23/1993
Collation 8p
The Jacob straight-line method of aquifer analysis deals with the late-time data and small radius of the Theis type curve which plot as a straight line if the drawdown data are plotted on an arithmetic scale and the time data on a logarithmic (base 10) scale. Correct analysis with the Jacob method normally assumes that (1) the data lie on a straight line, (2) the value of the dimensionless time factor is less than 0.01, and (3) the site's hydrogeology conforms to the method's assumptions and limiting conditions. Items 1 and 2 are usually considered for the Jacob method, but item 3 is often ignored, which can lead to incorrect calculations of aquifer parameters. A BASIC computer program was developed to analyze aquifer test data with the Jacob method to test the validity of its use. Aquifer test data are entered into the program and manipulated so that a slope and time intercept of the straight line drawn through the data (excluding early-time and late-time data) can be used to calculate transmissivity and storage coefficient. Late-time data are excluded to eliminate the effects of positive and negative boundaries. The time-drawdown data then are converted into dimensionless units to determine if the Jacob method's assumptions are valid for the hydrogeologic conditions under which the test was conducted.