Publications:CIRP-WN-11-2

PURPOSE: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes procedures to calculate salinity change within the Coastal Modeling System (CMS) operated in the Surface-water Modeling System (SMS). The CMS is a hydrodynamic and transport model designed for coastal and inlet applications and the SMS is a graphical user interface utility for PCs as developed by the U.S. Army Corps of Engineers (USACE). The procedure and the CMS verification are illustrated by the salinity modeling in a coastal inlet system at Humboldt Bay, CA, and in a wetland area of Breton Sound estuary, LA.

INTRODUCTION: Salinity refers to the salt content of water. Its value runs typically from 0 for fresh water to 31-35 ppt (parts per thousand) for ocean water. In water bodies with poor mixing and limited water exchange, or experiencing high evaporation, salinity can be higher and lead to formation of brine. Table 1, taken from the Wikipedia, presents typical values and nomenclature for describing degree of saline water:

${\frac {\partial (Sd)}{\partial t}}+{\frac {\partial (S{{q}_{x}})}{\partial x}}+{\frac {\partial (S{{q}_{y}})}{\partial y}}={\frac {\partial }{\partial x}}\left[{{K}_{x}}d{\frac {\partial S}{\partial x}}\right]+{\frac {\partial }{\partial y}}\left[{{K}_{y}}d{\frac {\partial S}{\partial y}}\right]+(P-E)S$