| Abstract: | Ground-water capture zone boundaries for individual pumped wells in a confined aquffer were delineated by using groundwater models. Both analytical and numerical (semi-analytical) models that more accurately represent the $round-water-flow system were used. All models delineated 2-dimensional boundaries (capture zones) that represent the areal extent of groundwater contribution to a pumped well. The resultant capture zones were evaluated on the basis of the ability of each model to realistically rapresent the part of the ground-water-flow system that contributed water to the pumped wells. Analytical models used were based on a fixed radius approach, and induded; an arbitrary radius model, a calculated fixed radius model based on the volumetric-flow equation with a time-of-travel criterion, and a calculated fixed radius model derived from modification of the Theis model with a drawdown criterion. Numerical models used induded the 2-dimensional, finite-difference models RESSQC and MWCAP. The arbitrary radius and Theis analytical models delineated capture zone boundaries that compared least favorably with capture zones delineated using the volumetric-flow analytical model and both numerical models. The numerical models produced more hydrologically reasonable capture zones (that were oriented parallel to the regional flow direction) than the volumetric-flow equation. The RESSQC numerical model computed more hydrologically realistic capture zones than the MWCAP numerical model by accounting for changes in the shape of capture zones caused by multiple-well interference. The capture zone boundaries generated by using both analytical and numerical models indicated that the curnmtly used 100-foot radius of protection around a wellhead in South Carolina is an underestimate of the extent of ground-water capture for pumped wetis in this particular wellfield in the Upper Floridan aquifer. The arbitrary fixed radius of 100 feet was shown to underestimate the upgradient contribution of ground-water flow to a pumped well. |
| Genre: | USGS Numbered Series |
| ProdID: | 28227 |
| Citation Author: | Landmeyer, J. E. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | iv, 33 p. :ill., maps ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 94-4012 |
| Citation Search Results Text: | Description and application of capture zone delineation for a wellfield at Hilton Head Island, South Carolina; 1994; WRI; 94-4012; Landmeyer, J. E. |
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| Citation Year: | 1994 |
| Type: | citation/reference |
| Text: | Description and application of capture zone delineation for a wellfield at Hilton Head Island, South Carolina; 1994; WRI; 94-4012; Landmeyer, J. E. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1994/4012/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1994/4012/report.pdf |
| Date Other: | Sat, 1 Apr 1995 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
