This is not about rising sea levels and global warming – the visibly obvious.
This is very much about aquifers – the invisibly not-so-obvious.
You do not need to be a blog follower to understand the importance of freshwater to life on Planet Earth – or any other planet (to the very best of our knowledge). I have tried to show the relationship and balance needed to raise our awareness of the challenges of our actions. This is always most evident for things above ground. We can see litter and trash; oil spills; deforestation; smog etc. We can only guess at the true condition of unseen spaces.
Aquifers are one of those hidden, subsurface spaces.
While all aquifers are important, this post is about a very specific category: coastal aquifers. Whether you are aware of this following fact – or not, it is important. In coastal groundwater, there exists a
“naturally established equilibrium between saltwater and freshwater.”
Scientists have long understood that
“seawater is drawn into aquifers as the freshwater-saltwater interface or boundary moves landward during winter. The water discharges back into coastal waters as the boundary moves seaward in summer.”
But scientists from MIT and Woods Hole also discovered in this 2005 study (Freshwater and Saltwater Interactions in Coastal Groundwater Systems May Provide Clues to Chemicals Entering Coastal Waters) that there exists
“a lag in the inflows and outflows related to seasonal changes in the water table.”
That exchange is important to understand because of the implications to this balance. But that detail is also NOT the focus of this post. The focus of this post if about one particular coastal aquifer and the impact that the water needs of coastal communities are having on its health.
The aquifer in question is the Floridan Aquifer.
Now that we understand there is a real connection between coastal freshwater and ocean seawater, let’s add the next important variable to this equation. It is the variable that seems to be involved in most of the consequential impact on our environment – humans.
The human factor in question is “overdraft”. The term overdraft has one immediate negative implication. An overdraft from a personal checking account at the bank will usually incur a penalty fee. So, too, there is a penalty if we overdraft an aquifer – especially a coastal aquifer.
In the article: Overdraft, Saltwater Intrusion Strain the Floridan Aquifer, the penalty is more than just a fine. It is about the potential long-term contamination of an underground freshwater reserve with saltwater from the coastal ocean.
From the USGS Floridan Aquifer System:
“The Floridan aquifer system is one of the most productive aquifers in the world. This aquifer system underlies an area of about 100,000 square miles in southern Alabama, southeastern Georgia, southern South Carolina, and all of Florida.”
Here is where the human element comes into vivid display.
“By 1950, withdrawals of freshwater from the Floridan for all purposes totaled about 630 million gallons per day; by 1980, nearly five times this volume, or about 3 billion gallons per day, was being pumped. The dominant factors causing this increase were the expansion of agriculture, industry, and mining, and the increased demand for public water supplies, especially in Florida where the population served by the Floridan aquifer system nearly tripled during this 30-year period. Significant changes in the use of water from the Floridan occurred between 1950 and 1980. The major changes have been in the percentage of withdrawal used for agricultural purposes, primarily irrigation, which more than tripled.”
And, as we shall see, there are consequences – penalties – to be incurred from these continually large withdrawals – overdrafts. From the article cited above,
“…a South Carolina island resort community announced last week that it was shutting down one of its wells because saltwater had soured the supply. It became the sixth of the district’s dozen wells to be sealed in the last decade due to saltwater displacing fresh groundwater, signaling a potentially dangerous new trend for the water supply of millions of people in the Southeast.”
The oceans are indeed coming – NOT FROM ABOVE, but from below. This change in coastal aquifers is already causing the increased use of desalinization to provide “fresh” water to communities affected by declining access to traditional freshwater supplies. We should expect this will only get worse in the future.
It would be a lot more convenient for humans if we could simply pay a penalty fine and move on. Nature doesn’t work that way.