Testing alternative conceptual models of seawater intrusion in a coastal aquifer using computer simulation, southern California, USA

Hydrogeology Journal
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Abstract

Two alternative conceptual models of the physical processes controlling seawater intrusion in a coastal basin in California, USA, were tested to identify a likely principal pathway for seawater intrusion. The conceptual models were tested by using a two-dimensional, finite-element groundwater flow and transport model. This pathway was identified by the conceptual model that best replicated the historical data. The numerical model was applied in cross section to a submarine canyon that is a main avenue for seawater to enter the aquifer system underlying the study area. Both models are characterized by a heterogeneous, layered, water-bearing aquifer. However, the first model is characterized by flat-lying aquifer layers and by a high value of hydraulic conductivity in the basal aquifer layer, which is thought to be a principal conduit for seawater intrusion. The second model is characterized by offshore folding, which was modeled as a very nearshore outcrop, thereby providing a shorter path for seawater to intrude. General conclusions are that: 1) the aquifer system is best modeled as a flat, heterogeneous, layered system; 2) relatively thin basal layers with relatively high values of hydraulic conductivity are the principal pathways for seawater intrusion; and 3) continuous clay layers of low hydraulic conductivity play an important role in controlling the movement of seawater.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Testing alternative conceptual models of seawater intrusion in a coastal aquifer using computer simulation, southern California, USA
Series title Hydrogeology Journal
DOI 10.1007/s100400050116
Volume 5
Issue 3
Year Published 1997
Language English
Publisher Springer
Description 15 p.
First page 60
Last page 74