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Temporal changes in the vertical distribution of flow and chloride in deep wells

Ground Water

By:
, , , ,
DOI: 10.1111/j.1745-6584.2005.0032.x

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Abstract

The combination of flowmeter and depth-dependent water-quality data was used to evaluate the quantity and source of high-chloride water yielded from different depths to eight production wells in the Pleasant Valley area of southern California. The wells were screened from 117 to 437 m below land surface, and in most cases, flow from the aquifer into the wells was not uniformly distributed throughout the well screen. Wells having as little as 6 m of screen in the overlying upper aquifer system yielded as much as 50% of their water from the upper system during drought periods, while the deeper parts of the well screens yielded 15% or less of the total yield of the wells. Mixing of water within wells during pumping degraded higher-quality water with poorer-quality water from deeper depths, and in some cases with poorer-quality water from the overlying upper aquifer system. Changes in the mixture of water within a well, resulting from changes in the distribution of flow into the well, changed the quality of water from the surface discharge of wells over time. The combination of flowmeter and depth-dependent water quality data yielded information about sources of high-chloride water to wells that was not available on the basis of samples collected from nearby observation wells. Changing well design to eliminate small quantities of poor-quality water from deeper parts of the well may improve the quality of water from some wells without greatly reducing well yield. Copyright ?? 2005 National Ground Water Association.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Temporal changes in the vertical distribution of flow and chloride in deep wells
Series title:
Ground Water
DOI:
10.1111/j.1745-6584.2005.0032.x
Volume
43
Issue:
4
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
531
Last page:
544
Number of Pages:
14