Saltwater Intrusion


Saltwater intrusion affects coastal areas when saline water infiltrates freshwater resources. It may be caused by sea level rise, storm surge, canals, excessive pumping of groundwater in coastal aquifers, or other factors. Automated monitoring systems can help to detect the incidence of saltwater intrusion, track long-term trends and provide warning when conditions are changing.

Saltwater Intrusion Measurements

Both humans and habitats for plant and animal life can be affected by saltwater intrusion. It is an issue faced by coastal communities around the world. Monitoring helps to understand both the causes and effects.
Droughts increase demand on surface and groundwater resources that normally counteract the forces of inland-moving saltwater.
Pumping in coastal aquifers can draw down the groundwater table while simultaneously drawing up saltwater contained in deeper layers.
Wells infiltrated with groundwater may no longer be suitable for agricultural application or drinking water supply.
Canal construction or leaks from existing canals can introduce saltwater much farther inland than it would naturally occur.
Rising sea levels may push the freshwater-saltwater interface further inland and allow storm surge to more easily breach levees and other control barriers.
Sudden introduction of increased salinity to an ecosystem may reduce biodiversity by killing or driving away native wildlife.

Saltwater Intrusion System

Salinity is calculated indirectly through conductivity and temperature measurement. Higher salinity means more ions in water, and higher ionic concentration increases the ability of water to conduct electrical current. Conductivity is also temperature-dependent, so saltwater intrusion monitoring therefore involves placement of conductivity and temperature sensors in a coastal watershed or aquifer. Multiple sensors are often used, for example a groundwater well with sensors at various depths.

NexSens saltwater intrusion monitoring systems utilize reliable, field-proven instruments for salinity measurement. Instruments from leading manufacturers such as YSI, Hydrolab, Eureka and Insitu are compatible with the X3 data logger, the central component of NexSens monitoring systems. The X3 transmits real-time data to the WQData LIVE web datacenter via 4G LTE cellular or Iridium satellite telemetry. WQData LIVE has a suite of data management tools and alerts to changing conditions via email or SMS text message.

Tipping bucket rain gauges are commonly integrated for precipitation measurement, while the Stevens HydraProbe is a popular sensor for its suite of soil temperature, moisture and conductivity measurements. Advanced systems can even incorporate water flow sensors to quantify reduction of stormwater runoff.

Flexible mounting options for the X3 simplify installation in the field, and power supplied with SPseries solar power packs allows for continuous operation. Waterproof UW connectors and automatic sensor detection streamline system start-up.

Multiple sensor ports on the X3 facilitate connection of several sensors in a system, including expansion with other sensor types such as pressure transducers for water level measurement and meteorological instruments like tipping bucket rain gauges and multiparameter met sensors.

Contact a NexSens Applications Engineer today to discuss your saltwater intrusion monitoring application.

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