I am taking the week off and will return with an original column on April 6th. For this week, let me explain why current events in South Florida are calling to mind a column I wrote a couple of years ago.

In the spring of 2012, I wrote a five-part series on water. In Part IV: When the Well Runs Dry, I explained the process by which salty ocean water can infiltrate subsurface fresh water aquifers and the problems that creates. Over the last couple of weeks, I have encountered several stories about salt water infiltration in South Florida’s Biscayne Aquifer.

The six million people who live in South Florida get 80-90 percent of their fresh water from the Biscayne Aquifer. Like all fresh water aquifers near to the ocean, a delicate hydraulic balance exists that prevents the salt from migrating too far inland. As the level of the Biscayne aquifer drops due to fresh water withdrawals and the local sea level continues to rise due to global warming, the hydraulic balance is being altered and the salt is coming ashore. In some places, subsurface salt water has reached six miles inland. As an example of the impact, consider that the town of Hallandale Beach, which is situated between Miami and Fort Lauderdale, has had to shut down all of its fresh water wells and import water from elsewhere. If the entire Biscayne Aquifer became contaminated with salt, the results to the local economy would be dramatic.

This situation is yet another example of the intersection of science and public policy that both interests and often frustrates me. We need to remember when setting public policy, such as limits on fresh water withdrawal rates, that physics matters. Given that public officials in Florida are currently prohibited from speaking the words “climate change,” the prospects for more science-based governance are not good.

So as we here in the Southern Part of Heaven consider who to vote for in local, statewide, and national elections, please give strong consideration to whether or not the candidates are guided by science.

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