| Abstract: | Electric-analog design criteria are established from the differential equations of ground-water flow for analyzing pumping-test data. A convenient analog design was obtained by transforming the cylindrical equation of flow to a rectilinear form. The design criteria were applied in the construction of an electric analog, which was used for studying pumping-test data collected near Grand Island, Nebr.
Data analysis indicated (1) vertical flow components near pumping wells in unconfined aquifers may be much more significant in the control of water-table decline than radial flow components for as much as a day of pumping; (2) the specific yield during the first few minutes of pumping appears to be a very small fraction of that observed after pumping for more than 1 day; and (3) estimates of specific yield made from model studies seem much more sensitive to variations in assumed flow conditions than are estimates of permeability. Analysis of pumping-test data where vertical flow components are important requires that the degree of anisotropy be known. A procedure for computing anisotropy directly from drawdowns observed at five points was developed. Results obtained in the analog study emphasize the futility of calculating unconfined aquifer properties from pumping tests of short duration by means of equations based on the assumptions that vertical flow components are negligible and specific yield is constant. |
| Genre: | USGS Numbered Series |
| ProdID: | 2744 |
| Citation Author: | Stallman, Robert W. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | - |
| Citation Editor: | |
| Citation End Page: | |
| Citation Issue: | |
| Citation Keywords: | |
| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | iv, 37 p. :ill. ;23 cm. |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | U.S. G.P.O., |
| Citation Series: | Water Supply Paper |
| Citation Series Code: | WSP |
| Citation Series Number: | 1536-H |
| Citation Search Results Text: | Electric analog of three-dimensional flow to wells and its application to unconfined aquifers; 1963; WSP; 1536-H; Stallman, Robert W. |
| Citation Start Page: | |
| Citation Volume: | |
| Citation Year: | 1963 |
| Type: | citation/reference |
| Text: | Electric analog of three-dimensional flow to wells and its application to unconfined aquifers; 1963; WSP; 1536-H; Stallman, Robert W. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wsp/1536h/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wsp/1536h/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. G.P.O., |
