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Effects of model layer simplification using composite hydraulic properties

Hydrogeology Journal

By:
and
DOI: 10.1007/s10040-009-0505-4

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Abstract

The effects of simplifying hydraulic property layering within an unconfined aquifer and the underlying confining unit were assessed. The hydraulic properties of lithologic units within the unconfined aquifer and confining unit were computed by analyzing the aquifer-test data using radial, axisymmetric two-dimensional (2D) flow. Time-varying recharge to the unconfined aquifer and pumping from the confined Upper Floridan aquifer (USA) were simulated using 3D flow. Conceptual flow models were developed by gradually reducing the number of lithologic units in the unconfined aquifer and confining unit by calculating composite hydraulic properties for the simplified lithologic units. Composite hydraulic properties were calculated using either thickness-weighted averages or inverse modeling using regression-based parameter estimation. No significant residuals were simulated when all lithologic units comprising the unconfined aquifer were simulated as one layer. The largest residuals occurred when the unconfined aquifer and confining unit were aggregated into a single layer (quasi-3D), with residuals over 100% for the leakage rates to the confined aquifer and the heads in the confining unit. Residuals increased with contrasts in vertical hydraulic conductivity between the unconfined aquifer and confining unit. Residuals increased when the constant-head boundary at the bottom of the Upper Floridan aquifer was replaced with a no-flow boundary.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Effects of model layer simplification using composite hydraulic properties
Series title:
Hydrogeology Journal
DOI:
10.1007/s10040-009-0505-4
Volume
18
Issue:
2
Year Published:
2010
Language:
English
Publisher:
Wiley
Contributing office(s):
Florida Water Science Center-Orlando
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrogeology Journal
First page:
405
Last page:
416
Country:
United States
State:
Florida
County:
Lake County;Volusia County
Other Geospatial:
Carrot Barn Sur?cial Aquifer System Well ?eld;Lyonia Preserve Sur?cial Aquifer System Well ?eld