Crystal River/ Kings Bay Hydrogeology

Introduction

Governor Reubin O'Donovan Askew on September 22, 1971, in Miami, Florida declared, "We must ensure our continuing economic prosperity, but the price we pay for growth must be carefully evaluated. We must recognize that the destruction of Florida is a price too high. Ecological destruction in Florida is nothing less than economic suicide."

The Water Resources Act, 1972, declared Florida water a resource of the state, and not owned by any individual landowner. Five Water Management Districts were formed and delegated by the Department of Environmental Protection (then the Department of Natural Resources) to manage the waters to meet all reasonable and beneficial uses of the people of Florida by a system of permits. Also enacted were the Environmental Land and Water Management Act, the Comprehensive Planning Act, and the Land Conservation Act.

Dr Robert O. Vernon

In the research report of the late Dr. Robert O. Vernon, 1951, is a remarkable map of Florida, not the land, roads, buildings and forests, but showing the pressure of water in the aquifer under the ground. He called lines on the map piezometric contours, (meaning, piezo = pressure, metric = measure, contour = line joining points of equal measure).

A region of high pressure lies to our southeast in Polk county. Another high lies to our northeast between Alachua and Putnam counties. Citrus County, in a lower pressure area, receives flow both from the north and the south as waters flow from high pressure areas to lower ones. This piezometric flow, is a modest flow through a system of smaller and larger holes in the limestone.

The origin of Florida's ground water is rain precipitation from the atmosphere. On passing through the atmosphere, the falling rain water becomes charged with carbon dioxide gas that combines with water to form carbonic acid. Humic acids from rotting vegetation are added on contact with the ground to form the natural solvent for limestone. As this acid-charged water soaks into the ground, limestone rock is dissolved to make the holes.

For the first time, Dr Vernon also showed location of many fracture sets, or fissures, in the aquifer rocks, created some millions of years ago as the land emerged from marine formations.

When peizometric flows encounter a fracture set the water flows combine to follow a path of least resistance in the direction of the fracture. Moreover, the increased quantities of acidic water flowing faster, increase the size of the fracture conduit over time. Enlarging some areas into huge cavern complexes along the way.

As these underground "conduit" flows break the surface to air or vent into another water body, a spring is formed. Sometimes the roof of an underground cavern collapses to form a really big spring.

Three major fracture sets and two fault lines are indicated near Crystal River. The two most easterly ones are referred to as fault lines. The three lying to the west are identified as fracture sets. The five lines run parallel to each other. The fracture sets, although shown as a single line, usually comprise several parallel fissures in the rock spaced a few feet up to several hundred feet apart. Between these major sets, depicted by Dr Vernon, can lie lesser fracture sets. An example of this, where the fissures can clearly be seen from the banks of Black Spring (Lat. 28° 52’ 38.63”, Long. 82° 35’ 57.20”). Several other vents were served by the same line of fractures in Kings Creek and into Kings Bay, for example, the 'hook' of Hook Island, and on land in between. (Not all continue to flow.)

The east-most line of fracture sets runs from about ten miles south east of Kings Bay shoreline and under Kings Bay continuing beyond Bagley Cove. This fracture set is the source of water delivered by Tarpon Hole (also known as King Spring, Lat. 28° 52’ 54.42”, Long. 82° 35’ 41.01”) as a first magnitude spring. Several vents emit water in that same locality. Smaller springs are also fed before and after Tarpon Hole along this general line.

Dr Glen L. Faulkner

In 1973, the U.S. GEOLOGICAL SURVEY completed the Water-Resources Investigations Report, I-73, GEOHYDROLOGY OF THE CROSSFLORIDA BARGE CANAL AREA WITH SPECIAL REFERENCE TO THE OCALA VICINITY (Prepared in cooperation with: U.S. DEPARTMENT OF THE ARMY CORPS OF ENGINEERS). Dr Faulkner's report illustrates the importance of understanding the geological influences upon ground water flows in an aquifer system and the way to build upon work other distinguished authors, such as Dr Vernon.

Dr Faulkner affirmed the general southerly direction of the piezometric flows and the influence of the north east to south west alignment of the fracture sets, which serve to concentrate and channel the peizometric flows.

With regard to the source of fresh water to Crystal River/Kings Bay, it is more than likely that the NE to SW fracture set shown in Figure 17, which runs from Ocala, extends all the way to Hunter Spring run to feed the spring group in that region of Kings Bay. (It is thought that the early termination of this fracture might well coincide with the lack of aerial photographs referred to by Vernon on page 47 of his 1951 paper, and being obscured by the overburden of the Brookesville Ridge). This would tend to be true if that fracture set were to bear the same characteristic length as those other orthogonals depicted on the Vernon, Figure 11, mapping on which the Faulkner, Figure 17, is based.

The fracture sets and equipotential lines pre-date the formation of Lake Rousseau by many centuries. Potentiometric flow from the high to the north of the Lake Rousseau would appear to merge with the flow originating to the east and south of the Rainbow River in the area of northeast Citrus County. This would also appear to strengthen the ground water stream along the fracture set passing through that area leading southwestward to the Hunter Spring Run / Three Sisters Spring group in Kings Bay.

On page 111, of the I-73 report, Mr Faulkner writes: "Additional geological information should be gathered by examination of good sets of lithologic samples available from test holes and wells. Various remote sensing methods, such as aerial infrared and color photography, should be investigated and utilized where possible to aid in the delineation of certain stratigraphic and structural characteristics of the area, the knowledge of which may help to further define routes of preferential ground-water flow, and thereby aid in preventing pollution of water in the aquifer. [Foundation's emphasis]"

The two figures 17 and 22 from the report are included to underline the relationship between potentiometric flows and conduit flows along fracture sets and fault lines.

Thus, the angular transitions of the general flow line of Crystal River would appear to follow the fracture sets along its path, as predicated by Vernon. Flowing NW from its origin with the springs in the south region of Kings Bay, turning more westerly as it is joined by flows from Hunter Spring run, then more northerly as joined by the fracture set running parallel to and set to the west of the initial Kings Bay direction, and on out to the Gulf. See the illustration below.

Kings Bay Fracture Sets This view of Crystal River/ Kings Bay, taken from Google Earth, illustrates how waters flow into Kings Bay from fracture sets through several of it's Springs, including Tarpon Hole, and Black Spring. The reddish line through Tarpon Spring and Shark Sink originated with Dr Vernon's (1951) report. (The position of the various springs along that line confirms the validity of the earlier work). Similarly, observations on the ground and the precise positioning of Black Spring, the three sinkholes shown on the bluish line, and the six springs fed from the fracture set conduit authenticate that fracture set. The piezometric flow of water from the southeast is concentrated in the conduits aligned with the general direction of Crystal River from the point of exit from the springs towards Bagley Cove. This is supported by Dr Sam Upchurch (reported in SWFWMD documents, and verbally with this author) that flows into Kings Bay also originate from the southeast (and, incidentally, also from the northeast). [See also Fracture Sets Example] The position of the springs was taken from, "The Hydrology and Water Quality of Select Springs in the Southwest Florida Water Management District" - Prepared by the Water Quality Monitoring Program, in May, 2001, (pages 51 to 53), and from the VHB report to the SWFWMD dated March 31, 2009. The fracture sets depicted, as with most, show the line of several parallel fissures comprizing a fracture set. This is evident with the different vents comprizing Tarpon Spring, and the several vents within the vicinity of Black Spring. Four parallel fractures still flow in Kings Creek. Several others are clearly in evidence, which were once in operation but now do not flow having been stopped deliberately by developers or householders, or upon becoming silted up by natural events. Both the Black and Tarpon Spring fracture set conduits have a width at the surface exceeding 800 feet which is expected to be the case along their course before becoming evident at the surface. It is noteworthy that, in addition to indicating the course of several parallel fissures, the fractures also capture flows according to their depth, in a similar way to a well which has a Cone of Influence. Thus, the feed from these fracture sets may accept and deliver underground water flows beneath a land surface up to hundreds of feet wide. This emphasizes the imperative to prevent pollution in the aquifer, (from page 111, from Dr Faulkner's document above), if the Outstanding Florida Waters of Crystal River / Kings Bay are to be preserved for the future and as a source of significant economic wealth for the community. This lower view, on adopting a higher elevation viewpoint, illustrates the position of sinkholes on the fracture sets confirming their existence, under decision rules adopted by the United States Army Corps of Engineers and others. The entire database of Florida sinkholes was incorporated into Google Earth to verify the sinkholes on lineaments which testify to the veracity of probable fracture sets prior to physical ground-truthing, as those depicted in these illustrations. It is quite likely that the collection of spring vents colored orange may be identified with fracture set conduits parallel to and between the Black and Tarpon Spring fracture sets, as indicated by the presence of sinkhole 02-046.