Water is essential. We need it for drinking, to maintain life in an urban environment, and for manufacturing or industrial purposes. We also need it to maintain our natural environment—to sustain wildlife and to keep the ecosystem healthy and in balance. The water we need and have in our area comes from above, from below and from all sides. It is one of the reasons why our area is so green and fertile. Think about the beautiful mangroves by the beach or the lushness of Snyder Park.
Unfortunately, too much water, or too much sea water where fresh water should be, is not good. Natural coastal ecosystems can change too much, and the plant and animal communities need to adapt or move, or they will die out.
For our area to be habitable for most plants, animals and humans, we need just the right amount of water in the right places. Land needs to be able to absorb water and/or re-direct it to keep the aquifer full without water spilling onto the streets or over-soaking green spaces. Rising sea level compromises the land’s natural ability to do that.
In our area, rain water (known as stormwater) is absorbed through just a few feet of porous, sandy soil. When that land gets saturated, water flows over and through to the next layer, which in our case is porous limestone rock. Our drinking water aquifer, the Biscayne Aquifer, sits within this layer of limestone rock and is replenished by rainfall. But the shallow, porous nature of the aquifer also makes it susceptible to saltwater intrusion and other contaminants.
Increasing rainfall, sea water flowing under us, tidal surges during extreme weather events and prior damage to the Everglades all contribute to Fort Lauderdale’s saturation. Like a wet sponge, the ground becomes soaked through at all levels and water simply oozes up and over. Normal rain storms start to become too much of a good thing. They begin to produce the inevitable hazard of puddle water on the streets. According to representatives of the University of Florida’s Florida Sea Grant College Program, there are places in our region that now regularly “flood at high tide… The flood control system in South Florida, constructed by the U.S. Army Corps of Engineers in the 1960s, no longer has the capacity to adequately provide flood protection in many areas because of today’s higher sea level.” This creates major challenges for all of us during heavy rainstorms, but particularly for water and emergency managers. It is no secret that when it rains here in Fort Lauderdale, most of us know which streets to avoid.
The same phenomenon works in reverse. As good as that limestone rock is for letting water back into the aquifers, it is just as good for letting the ocean through to us as the sea rises. This is known as salt water intrusion – when the ocean goes where there was previously only freshwater.