How our world is impacted
Access to freshwater is imperative for the survival of both plants and animals so, as water sources become contaminated with salt, natural ecosystems become unstable. Obviously, humans are not exempt from these effects. According to the Stockholm International Water Institute, “at least 2 billion people of the 7.6 billion on Earth use groundwater as their primary source of water”. This reliance on groundwater means that nearly 50% of the world’s aquifers are being depleted and may not be capable of natural recovery.
As saltwater intrusion increases, populations of people are losing access to drinking water, resulting in conflict. Food also becomes scarce when saline stunts or prevents crop growth, thereby putting more stress on already strained families.
Even when rainfall does arrive and replenish groundwater, the intrusion of saltwater leaves scars on the land. Due to the chemical properties of saltwater, more nutrients dissolved in it and are carried away, leaving once fertile land unable to grow crops. This, in turn, leads to algal blooms that kill aquatic species when the nutrients are carried into local waterways. As you can imagine, this chain reaction of events makes it difficult to predict just how much any given region will be impacted. The best we can do is try to prevent it from happening.
How is saltwater intrusion monitored?
To prevent saltwater intrusion, we first must understand how these problems are occurring. To do so, scientists are monitoring various groundwater parameters in affected areas to detect changes over time. The most common method is to drill multiple wells in a region so samples from varying depths can be analyzed. This may mean collecting samples in bottles and sending them to labs–or inserting water quality sensors like the pHionics STs Series™ down wells to track salt intrusion in real time. Common collected data includes depth-to-water, conductivity, pH, temperature, and optionally dissolved oxygen, ORP, or turbidity. By tracking these in multiple wells, scientists create a map of groundwater levels and determine the interface location of fresh and saltwater.