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V. T. Stringfield

Publications and source records attributed to V. T. Stringfield.

16 recordsLinked to original sources
USGS2014

The Piezometric surface of artesian water in the Florida peninsula

The ground‐ water of the Florida Peninsula constitutes one of its most valuable natural resources and is of importance as a source of water ‐supplies throughout the area. The problems relating to the development of ground‐ water supplies are both quantitative and qualitative. They include such problems as the decline in yield of wells in areas of large withdrawals of water and salt‐ water contamination of ground‐ water supplies. In order to facilitate a better understanding and interpretation of hydrologic conditions relating to these local ground‐ water problems, a general survey of the artesian water in the Florida Peninsula was made by the United States Geological Survey in 1934.

Florida↗
USGS2014

Report of Committee on Ground Water, 1943–44

The Chairman extends an apology to G. W. MUSGRAVE for omission of his name from the list of members given in the report of the Committee on Ground Water for 1942–43. The response from members of the Committee in general has been very gratifying and is much appreciated. Four new members, Messrs. H. F. BLANEY, EDWARD BURWELL, Jr., A. N. SAYRE and V. T. STRINGFIELD have been added to the Committee this year, in order to effect better technical and geographic coverage.

Eos, Transactions, American Geophysical Union↗
USGS2006

Water levels in carbonate rock terranes

Many subtle aspects of water levels in carbonate rocks need to be put in perspective even though hydrologists have recognized the fundamental value of characteristics of ground-water levels. The depth to the water table in carbonate rocks is controlled by local factors such as permeability and topography and by the regional factor of climate; both permeability and topography are dynamically developed according to the degree of preferential circulation of subsurface water and of solution of the rock, and the water table responds by lying deep beneath hilly permeable karstlands and shallow beneath flat and poorly permeable carbonate rocks. The uneven distribution of permeability and of topographic conditions is responsible for the intriguing karst phenomena of disappearing and reappearing surface streams. Great infiltration capacities of some karst regions result in large local fluctuations of the water table and in some cases to local reversals in direction of ground-water flow between wet and dry seasons. Water-level behavior in space and time is a primary consideration for interpreting the hydrology of carbonate terranes.

Groundwater↗
USGS1979

Effects of karst and geologic structure on the circulation of water and permeability in carbonate aquifers

The results of the natural processes caused by solution and leaching of limestone, dolomite, gypsum, salt and other soluble rocks, is known as karst. Development of karst is commonly known as karstification, which may have a pronounced effect on the topography, hydrology and environment, especially where such karst features as sinkholes and vertical solution shafts extend below the land surface and intersect lateral solution passages, cavities, caverns and other karst features in carbonate rocks. Karst features may be divided into two groups: (1) surficial features that do not extend far below the surface; and (2) karst features such as sinkholes that extend below the surface and affect the circulation of water below. The permeability of the most productive carbonate aquifers is due chiefly to enlargement of fractures and other openings by circulation of water. Important controlling factors responsible for the development of karst and permeability in carbonate aquifers include: (1) climate, topography, and presence of soluble rocks; (2) geologic structure; (3) nature of underground circulation; and (4) base level. Another important factor is the condition of the surface of the carbonate rocks at the time they are exposed to meteoric water. A carbonate rock surface, with soil or relatively permeable, less soluble cover, is more favorable for initiation of karstification and solution than bare rocks. Water percolates downward through the cover to the underlying carbonate rocks instead of running off on the surface. Also, the water becomes more corrosive as it percolates through the permeable cover to the underlying carbonate rocks. Where there is no cover or the cover has been removed, the carbonate rocks become case hardened and resistant to erosion. However, in regions underlain not only by carbonate rocks but also by beds of anhydrite, gypsum and salt, such as the Hueco Plateau in southeastern New Mexico, subsurface solution may occur where water without natural acids moves down from bare rock surfaces through cracks to the beds that are more soluble than carbonate rocks. For example, in the area of Carlsbad Caverns in southeastern New Mexico, much of the water responsible for solution that formed the caverns apparently entered the groundwater system through large open fractures and did not form sinkhole topography. East of the Carlsbad Caverns, however, in the Pecos River Valley where the carbonate rocks are overlain by the less soluble Ogallala Formation of Late Tertiary age, solution began along escarpments as the Pecos River and its tributaries cut through the less soluble cover. As these escarpments retreated, sinkholes and other karst features developed. Joints or fractures are essential for initiation of downward percolation of water in compact carbonate rocks such as some Paleozoic limestone in which there is no intergranular permeability. Also joints or fractures and bedding planes may be essential in the initiation of lateral movement of water in the zone of saturation. Where conditions of recharge and discharge are favorable, groundwater may move parallel to the dip. However, the direction of movement of water in most carbonate rocks is not necessarily down dip or parallel to the dip. The general direction of movement of both surface and groundwater may be parallel to the strike in a breached anticline. Faults may restrict the lateral movement of water, especially if water-bearing beds are faulted against relatively impervious beds. Conversely, some fault may serve as avenues through which water may move as, for example, in the Cretaceous Edwards aquifer in the San Antonio area, Texas. Karst aquifers, chiefly carbonate rocks, may be placed in three groups according to water-bearing capacity. Water in aquifers of group 1 occurs chiefly in joints, fractures, and other openings that have not been enlarged by solution. The yield of wells is small. Aquifers in group 2 , with low to intermediate yields, are those in which water occurs in joints and fractures with some cavities and channels enlarged by solution. Aquifers in group 3 are those in which the yield of wells and springs range from intermediate to very large. This group includes five of the most productive aquifers in the U.S.A. The water-bearing beds of all of these productive aquifers, except the Biscayne aquifer in southeastern Florida, contain buried paleokarst in which the permeability has been reactivated and enlarged by the present circulation system.

Journal of Hydrology↗
USGS1973

Karst hydrology: A review

Karst regions of the world are characterized by limestones and other soluble rocks at or near land surface that have been modified by solutional erosion. Such surface features as sinks, long dry valleys, sparse streams, and bare rock and such subsurface features as caverns, arterial solution openings leading to large springs, and a deep water table are typical of karst terranes. These features result in an uneven distribution of permeability in karst systems and surface and subsurface hydrologic conditions that require special hydrogeologic studies. Local high permeability at shallow depth in mature karst regions leads to an ecology associated with a soilless and water-scarce surface environment. Many practical problems result from this high permeability, including: (1) scarcity and poor predictability of groundwater supplies; (2) scarcity of surface-water supplies; (3) instability of the ground; (4) leakage of surface reservoirs; and (5) an unreliable waste-disposal environment. Interest in karst hydrology has increased greatly in the past decade; this interest has resulted in the international exchange of numerous published reports on local areas and on special topical karst problems. Many of these reports have been used by the authors in preparing this paper, which synthesizes results of many workers and focuses attention on: (1) the development of karst features through hydrologic processes; and (2) hydrologic systems of karst terranes.

Journal of Hydrology↗
USGS1973

Concepts of karst development in relation to interpretation of surface runoff

Some unusual characteristics of streamflow occur in regions underlain by carbonate rocks. The streamflow characteristics are related to processes of karstification, these processes being dependent on circulation of subsurface water and solution of the rock to form characteristic topography and underground cavern systems. Very highly cavernous and permeable unsaturated zones tend to keep the water table depressed below land surface in many karst regions, a condition that leads to a low density of perennial streams. The uneven distribution of permeability beneath surface karst streams causes them to lose or gain water, depending on the position of the water table with reference to stream level. The conventional techniques of interpolation and extrapolation that have been reasonably successful in approximating streamflow of ungaged sites in nonkarstic regions have only limited use in karst regions. An understanding of principles of karstification and an understanding of the hydrogeologic framework of a carbonate terrane provide a useful basis for evaluating the streamflow characteristics.

Journal of Research of the U.S. Geological Survey↗
USGS1971

Tertiary limestone aquifer system in the southeastern states

The hydrogeologic history of the Tertiary limestone system of the Southeastern States is reconstructed, especially as it relates to circulation of ground water and the development of solution cavities. The development of these solution cavities resembles in many respects the development of cavities in carbonates of the Knox Group of Tennessee during Middle Ordovician time, the cavities in the Knox having since been filled with collapse breccia that has been recemented. Some general principles of the circulation of water in limestone terranes and the related development of solution openings are reviewed so that a generic basis for comparison can be made of the modern southeast carbonate setting with the Ordovician carbonate setting in Tennessee.The major requirements for solutional development as cavities--(1) presence of highly soluble material, (2) a fracture system or some other form of incipient permeability, (3) water undersaturated with respect to soluble rocks, such as recharge from precipitation, and (4) hydraulic gradient--are found in the Tertiary limestone terrane of the southeast; much of the limestone has been elevated above sea level as a homoclinal seaward-dipping unit. Such a broad homoclinal setting, which also existed in the Knox at the close of early Ordovician time, facilitates extensive solutional development in the upper part of the zone of saturation. Circulation of water great enough to form a significant cavern network requires concentrated discharge areas, commonly as entrenched permanent streams or near-shore springs and seepage. This condition prevails where the Tertiary limestone is fairly close to land surface.Reconstruction of the geologic and hydrogeologic history of a carbonate region generally reveals the extent of early solution and karst development in relation to current karstification. Caverns, partly filled in some cases with loose or poorly cemented rock fragments that have fallen from cavern roofs, give evidence of karstification that is either current or that probably developed since the last marine inundation of the carbonate terrane. On the other hand, filling of caverns with overlying rock debris and reconstituting the debris into breccia are conditions that require evaluation of paleohydrology.

Alabama, Georgia, Florida, North Carolina, South C↗
USGS1971

Effects of karst features on circulation of water in carbonate rocks in coastal areas

The normal balance between fresh water in coastal aquifers and sea water applies also to carbonate-rock aquifers that have been karstified, but there are local modifications in the balance that need to be considered. Uneven distribution of permeability, expressed by a network of solution channels bounded by relatively impermeabler rock, causes an uneven distribution of head of the environmental water along the seacoast. Where sinkholes and (or) vertical solution shafts below sea level penetrate the aquifer, the fresh ground water may discharge through these karst features if the fresh-water head is greater than that of the salt water. However, under some conditions the salt-water head may exceed that of the fresh water, and the direction of movement is reversed as sea water flows into the aquifer. This sea-water flow into the aquifer occurs (1) where sinkholes, acting as “cased wells,” penetrate less permeable rock before reaching a lateral solution channel and (2) where (or when) the fresh-water head is less than that required to balance the salt water. On Andros Island, Bahamas, the range in tide (as much as 5 feet) from low tide to high tide is sufficient to cause such a reversal locally. During low tide the salt-water head becomes sufficiently low that the ground-water head exceeds that of the sea water, and the ground water flows through the sinkholes to the ocean floor; during high tide sea water flows in the sinkholes. In the Adriatic Sea along the coast of Yugoslavia, apparently the fresh-water head is sufficient to produce perennial springs in some localities, but in other areas, as in the Bay of Kastela near Split, the fresh-water head becomes low enough during some seasons that the flow is reversed and salt water enters the aquifer through the karst features. The development of sinkholes and other karst features near the present coast and extending below sea level occurred generally during a low stand of the Pleistocene sea when the top of the saturated zone stood lower than the bottom of the deepest sinkholes or natural wells. Integrated evaluations of (1) the distribution of permeability in coastal karst regions and (2) the principles relating to the dynamic balance between fresh aquifer water and sea water are leading to better knowledge of methods that may salvage much karst water which is lost to the sea.

Split↗
USGS1969

Hydrology of carbonate rock terranes — A review: With special reference to the United States

Limestone and other carbonate rocks are characterized by many unusual features and extreme conditions, either involving the hydrologic system within them or wrought by hydrologic conditions on them or through them. Perhaps there could be little agreement as to what is typical or average for the many features of carbonate rocks, as indicated by the following conditions: bare rock and thin soils are common, but so are thick soils; very highly permeable limestones are common, but so are poorly permeable ones; and rugged karst topographic features with underlying solution caverns are common, but so are flat, nearly featureless topographic conditions. Some conditions of carbonate terranes are suitable to man's needs and interests, such as the use of some permeable aquifers for water supply and the exploitation of caves for tourist attractions. On the other hand, many problems may exist, including: permeability too low for adequate water supply or so high that the aquifer retains too little water for use during periods of fair weather, soils too thin for growing of crops and for adequate filtration of wastes near the ground surface, instability of the ground for buildings and foundations in sinkhole areas, and unusually rugged topography. Some of the many variable conditions are readily observable, but others can be determined only by careful geologic and hydrologic studies. The need for knowing the specific geologic and hydrologic conditions at various places in limestone terranes, as well as the variations in hydrologic conditions with changing conditions and time, has resulted in many published reports on local areas and on special topical problems of limestone hydrology. Many of these reports have been used to advantage by the present writers in preparing this paper. The concept that secondary permeability is developed by circulation of water through openings with the accompanying enlargement of these openings by solution is now universally accepted in limestone terranes. Emphasis is placed on the hydrogeologic framework, or structural setting, in relation to the ease or difficulty of water to move from a source of recharge, through a part of the limestone, to a discharge area. Parts of the limestone favored by circulating ground water tend to develop solution openings, commonly in the upper part of the zone of saturation; as base level is lowered (sea level or perennial stream level), the related water table lowers in the limestone leaving air-filled caverns above the present zone of saturation in sinkhole areas. Reconstruction of the geologic and hydrologic history of a limestone area aids in determining the extent of development and the positions of fossil and present permeability. References are made to the hydrology of many limestone regions, especially those of the United States.

Journal of Hydrology↗
USGS1969

Relation of sea water to fresh water in carbonate rocks in coastal areas, with special reference to Florida, U.S.A., and Cephalonia (Kephallinia), Greece

The principles controlling the equilibrium between the denser salty water and the lighter fresh water in coastal aquifers apply to carbonate as well as sand systems. However, under certain equilibrium conditions of fresh and salt water in parts of some carbonate aquifers unusual hydrologic phenomena result. Hydrologic conditions at Tarpon Springs, Florida, and Cephalonia, Greece, include deep vertical openings as sinkholes through a relatively impervious part of the aquifer system. In both cases the tops of the sinkholes or natural wells are exposed to sea water. At Tarpon Springs the dynamic equilibrium between salt water and fresh water fluctuates so that the flow of salt water from the spring to a lake 2 miles away is sometimes reversed. At Cephalonia, the head of fresh water does not exceed the head of salty water in the sinkholes; the flow of sea water into the aquifer, aided by a shallow channel from the sea, is continuous, and the water level in the sinkhole is continuously depressed below sea level. Both cases represent a partially confined U-tube system where water at the seaward, sinkhole end is denser than at the other end and where a low fresh-water head is less than the salt-water head.

Cephalonia, Florida↗
USGS1966

Hydrology of limestone terranes in the coastal plain of the Southeastern United States

T he very productive limestone aquifers of Tertiary and Quaternary age in the Coastal Plain of the Southeastern States contain a water-table circulation system where aquifers are at or near the land surface; the Tertiary limestone unit is a homoclinal artesian system confined beneath younger beds in coastal areas. The Tertiary limestone has a total thickness of several thousand feet and ranges in age from Paleocene to Pliocene. The part of the limestone that represents a hydrologic unit, as much as 1000 feet thick, ranges in age from middle Eocene to middle Miocene. That unit is the principal artesian aquifer in Florida and southeastern Georgia. It is also an aquifer, but of lesser importance, in South Carolina, North Carolina, and Alabama. In southeastern Florida the Quaternary limestone forms a shallow, although highly productive, aquifer. In general, the Tertiary formations dip gently toward the coast, except where the regional dip is interrupted by folds such as the Cape Fear arch, the Ocala uplift, and the Chattahoochee anticline, or by faults such as those on the Ocala uplift. A piezometric map showing the head of water in the principal artesian aquifer in Florida and southeastern Georgia reveals chief areas of recharge where limestone crops out in interstream areas and where sinkholes breach overlying beds; it reveals principal discharge areas in certain stream valleys, springs, and offshore. Lateral movement of the water in the limestone is generally controlled by the hydraulic gradient to the nearest discharge area. The movement may be either controlled by or independent of faults and folds; it may be along joints for short distances. Solution by downward movement of water in the zone of aeration to the water table has formed vertical tubular openings or shafts. Lateral movement of the water from areas of recharge to areas of discharge has formed caves and other solution channels, chiefly in the upper part of the zone of saturation. Since they were formed, some caves have been drowned, and others have been exposed in the zone of aeration as the water rose and fell, chiefly in Pleistocene time. The principal aquifer in Florida probably has caves and solution channels comparable in size and extent to those of Mammoth Cave, Kentucky; however, only a small percentage of these are above the water table at the present time. In a large part of the region the most noticeable change in chemical quality of the water in the limestone resulting from circulation of water is the freshening accompanying removal of salty water from the aquifer. Changes in sea level during Pleistocene time have raised and lowered the water table; thus the position of the upper part of the zone of saturation, in which conditions were most favorable for solution and for the formation of cavities, has changed repeatedly. At the lowest stand of the Pleistocene sea, it is conceivable that the water level in part of the limestone in north-central Florida was a few hundred feet lower than at present. The present pattern of solution openings probably was developed in Pleistocene time.

Southeastern United States↗
USGS1966

Development of permeability and storage in the tertiary limestones of the southeastern states, USA

Permeability and storage characteristics in the Tertiary limestone system of southern United States have developed progressively but non-uniformly as circulation of water and solution in the limestone have changed during the geologic and hydrologic history. The limestone formations, predominantly of Eocene age and subordinated of Oligocene and Miocene age, are widespread at and beneath the surface. They commonly dip gently seaward and are covered in coastal areas by Miocene to Recent clays and sands. Sinkholes and other karst features are common, but topographic relief is generally not great. Circulation of water under water-table conditions when the limestone was exposed to meteoric weathering, before middle Miocene time, resulted in development of secondary permeability as solution channels in near-surface parts of the limestone, Marine deposition of middle and late Miocene clays and later emergence converted part of the water-table circulation system to the present great artesian system. Later, Pleistocene changes in sea level caused changed in places where water discharged, which in turn caused changes in rates of circulation and changes in rates and positions of solution of limestone. Both present and past circulation of water have contributed to changes in permeability and storage of this limestone system.

Southeastern United States↗