The truth about sinkholes on the nature coast is that they have been a geological fact in the natural eco system of Central Florida for longer than us mere humans have been in existence.
Since the base material that makes up this area of Florida is limestone, it is very susceptible to damage from a variety of causes.
* Limestone Solution Sinkholes – Along the western portion of Lake County, limestone is exposed at the surface or is covered by a thin layer of soil. This leaves the limestone subject to both physical and chemical processes that break down the rock. When this breakdown occurs, it usually forms a saucer or bowl-shaped depression. Due to the natural dissolving of limestone, these sinkholes develop continuously, but slowly.
* Cover-Subsidence Sinkholes - Where the sand layer may be as thick as 50 to 100 feet, with very little clay below it, the dissolving limestone is replaced by granules of sand that cascade down to fill the void. This type of sinkhole is referred to as a cover-subsidence sinkhole. These sinkholes are only a few feet in diameter and depth. Their small size is due to the fact that the cavities in the limestone cannot develop to appreciable size before they are filled with sand.
* Cover-Collapse Sinkholes - Generally, the deeper the soils, more clay is present in the soils. This clay provides some cohesiveness to the soil material above it, allowing it to bridge an existing cavity in the limestone. If this "bridge" collapses, it results in what is called a cover-collapse sinkhole. See the graphic above. The size of the sinkhole depends upon the size of the cavity. Cover ¬collapse sinkholes form the same way as cover-subsidence sinkholes but differ mainly in the bearing strength of the soil above the cavity and whether the sinkhole subsides slowly or collapses abruptly.
* Content copied from http://www.lakecountyfl.gov
http://www.lakecountyfl.gov/departments/environmental_utilities/water_quality_services/sinkhole.aspx
Here in Hernando County, this can be seen as we drive down our roads. Weeki Wachee Springs, our States newest State Park, is not only the Nations deepest underwater cave system, it is a sinkhole. The small pond on the North side of SR 50 about three miles from US 19 is actually two sinks holes (Mary and Joe Sink. Along those same power lines, there are several other small ponds that are actually sinkholes (Lost Sink, Twin D's, etc) that have filled in with water over the years and become local swimming holes. I enjoyed these gifts from nature immensely in my youth and still do on those rare occasions, my spirit decides to write checks that my body finds difficult to cash. These are just a few of the more popular sinkholes in our County but there are many more that have become part of the local landscape.
One of the more famous sinkholes is Eagle's Nest to the west of SR 50 near Shoal Line Dr. on the way to Hernando Beach, Florida. Hernando County's waterfront area. This sinkhole is the Everest of cave diving. I have had the honor and privilege of experiencing this dive first hand and hold it to this day as one of the finest experiences of my life.
Our current drought is having an effect on the creation of sinkholes, this is a natural occurrence and part of a natural cycle. One we are still in the beginning phases of understanding.
Ground water pumping is also a cause of sinkhole formations. It is an unfortunate fact that the drought condition, of course, necessitates an increase in groundwater pumping. It is also a bit ironic that the rains, soon to begin, will also have an effect on sink hole formation.
In this area we have a water management organization, The Southwest Florida Water Management District. Their local offices are located:
2379 Broad Street, Brooksville, FL 34604-6899 (Google map)
Telephone: (352) 796-7211 or 1-800-423-1476 (FL only) http://www.swfwmd.state.fl.us/
This organization is affectionately called SwiftMud. For many years now they have been tasked with finding real and effective ways to deal with the sink hole issue here in Florida. Their plans are available for the general public here: http://www.swfwmd.state.fl.us/documents/
Yes, sinkholes are of course a concern here in the Nature Coast of Florida, and a prudent buyer should be aware of the area in which they are planning to buy. Talk to the neighbors, drive around the neighborhood. Remember a sinkhole is generally round, retention ponds are square. Your professional REALTOR can also help you with determining which areas are "potential problem areas" in this regard.
The Nature Coast of Florida, with Hernando County being its gateway, is a beautiful natural area, that needs to be understood and protected for future generations to experience. Solutions that reduce ground water pumping are necessary and over due, Public awareness of the cost of their fertilizers, lawn watering, building locations and the effect all these actions have on the surrounding Eco systems is also a goal that must be accomplished.
Sinkholes are a part of the experience and overall do more to contribute to the beauty of the area than they do physical damage.