Brine In The Near-Surface Environment: Determining Salinization Extent, Identifying Sources, And Estimating Chloride Mass Using Surface, Borehole, And Airborne Em

Electromagnetic (EM) methods can be used to locate salinized soil and water, identify likely<br>salinity sources, and estimate the total chloride mass in the saturated and unsaturated zone. Groundbased<br>EM measurements can be used to establish boundaries of the salinized area and determine the<br>range of electrical conductivity, borehole measurements and time-domain EM soundings can determine<br>the vertical extent of salinization and establish the relationship between ground conductivity<br>and chloride content, and airborne measurements can establish the lateral extent of salinization and<br>locate potential salinity sources. Total chloride mass in a salt-water plume can be estimated from<br>airborne EM data and the empirical chloride-conductivity relationship.<br>EM methods employed in geophysical studies of near-surface salinization owe their success<br>to the increase in electrical conductivity that occurs where saline water infiltrates saturated or unsaturated<br>geologic materials. EM data can also be combined with information on soil type, moisture<br>content, and water chemical composition to help identify geophysical signatures that distinguish<br>important causes of salinization such as natural saline seeps and springs, oil-field sources such as<br>brine-disposal pits and leaking oil or gas wells, and agricultural activities.