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Technical Note

Density Slopes in Variable Density Flow Modeling

Groundwater Tek Inc., Naples, FL 34119, USA
Academic Editor: Anis Younes
Water 2021, 13(22), 3292;
Received: 30 September 2021 / Revised: 12 November 2021 / Accepted: 15 November 2021 / Published: 20 November 2021
(This article belongs to the Special Issue Groundwater Flow Modeling in Coastal Aquifers)
Variable density flow (VDF) modeling is a valuable tool for assessing the potential impacts of global climate change and sea level rise on coastal aquifers. When using any of these modeling tools, a quantitative relationship is needed to compute the fluid density from salt concentration. A full understanding of the relationship between fluid density and solute concentration and the correct implementation of the equation of state are critical for variable density modeling. The works of Baxter and his colleagues in the early 20th century showed that fluid density could be linearly correlated to salt concentrations. A constant density slope of 0.7 is often assumed and applied. The assumption is reasonable when the salinity is less than 100‰. The density slope can also be defined from chloride concentration data with the assumption of a constant ratio (55%) between chloride and total dissolved solids (TDS). Field data from central Florida indicate that the chloride/TDS ratio can be as low as 5%. Therefore, TDS is the preferred water quality data for fluid density determination in variable density modeling. Other issues with density slope are also discussed, and some commonly used values of density slope are provided in this technical note. View Full-Text
Keywords: groundwater modeling; density slope; variable density flow; saltwater intrusion groundwater modeling; density slope; variable density flow; saltwater intrusion
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MDPI and ACS Style

Guo, W. Density Slopes in Variable Density Flow Modeling. Water 2021, 13, 3292.

AMA Style

Guo W. Density Slopes in Variable Density Flow Modeling. Water. 2021; 13(22):3292.

Chicago/Turabian Style

Guo, Weixing. 2021. "Density Slopes in Variable Density Flow Modeling" Water 13, no. 22: 3292.

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