U.S. GEOLOGICAL SURVEY CIRCULAR 968 

Development of Sinkholes Resulting 

From Man1

s Activities in the Eastern 

United States 

Development of Sinkholes Resulting 

From Man1

S Activities in the Eastern 

United States 

By J. G. Newton 

U.S. GEOLOGICAL SURVEY CIRCULAR 968 

1987 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging-in-Publication Data 

Newton, John G., 1929-

Development of sinkholes resulting from man's activities in the Eastern United 

States. 

(U.S. Geological Survey circular; 968) 

Bibliography: p. 40 

Supt. of Docs. no.: I 19.4/2:968 

1. Sinkholes-Southern States-Environmental aspects. 2. SinkholesNortheastern States-Environmental aspects. 3. Sinkholes-Middle 

West-Environmental aspects. I. Title. II. Series: Geological Survey 

circular ; 968. 

GB609.2.N47 1986 624.1 '51 85-600298 

Free on application to the Books and Open-File Reports Section, 

U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 
Abstract --------------------------------------

Introduction 

Scope and objectives ------------------------

Area of study ------------------------------

Method of investigation ---------------------

Acknowledgments --------------------------

Magnitude of sinkhole-related problems -----------

Distribution and significance of sinkholes ------

Hazards, damage, and pollution --------------

Development of subsurface openings --------------

Solution -----------------------------------

Mechanical erosion of bedrock and unconsolidated 

deposits ---------------------------------

Causes and occurrence of induced sinkholes --------

Decline of water level -----------------------

Loss of support -------------------------

Increase in velocity ----------------------

CONTENTS 

Page 

1 

1 

2 

3 

5 

5 

5 

6 

6 

8 

8 

10 

12 

14 

16 

20 

Causes and occurrence-Continued 

Decline of water level-Continued 

Water-level fluctuations ------------------

Induced recharge ------------------------

Occurrence and size ---------------------

Construction -------------------------------

Diversion of drainage --------------------

Impoundment of water -------------------

Occurrence and s~e ---------------------

Assessment of problem -------------------------

Recognition --------------------------------

Site evaluation -----------------------------

Prediction ---------------------------------

A voiding or mini~ing problems -------------

Summary and conclusions -----------------------

Selected references -----------------------------

ILLUSTRATIONS 

FIGURES 1, 2. Photographs showing: 

Page 

20 

24 

26 

28 

29 

29 

32 

32 

32 

34 

36 

38 

39 

40 

Page 

1. Collapse forming new sinkhole in Shelby County, Ala., 1972 ------------------------- 2 

2. Collapse forming new sinkhole in Winter Park, Fla., 1981 --------------------------- 3 

3, 4. Maps showing: 

3. Area of study and distribution of carbonate rocks ---------------------------------- 4 

4. Locations of sites of active sinkhole development ---------------------------------- 7 

5-7. Photographs showing: 

5. Collapse beneath railroad in Birmingham, Ala., in 1972 ----------------------------- 8 

6. Collapse of bridge over Anclote River near Tarpon Springs, Fla., in 1968 -------------- 9 

7. Sediment-filled solutionally enlarged opening extending downward from top of bedroc1

..- -- 10 

8. Cross section showing development of cavities in unconsolidated deposits --------------------- 11 

9, 10. Photographs showing: 

9. Inclined opening adjacent to cavity in residual clay in November 1970 in Birmingham, Ala. 12 

10. Cavity in residual clay in November 1970 in Birmingham, Ala. ----------------------- 13 

11. Composite photograph of cavity in residual clay in April 1971 in Birmingham, Ala. ------------- 14 

12. Map showing areas of induced sinkhole activity ------------------------------------------- 15 

13, 14. Schematic cross sections of: 

13. Interior terrane showing water-level decline and resulting sinkhole development -------- 17 

14. Coastal terrane showing decline in potentiometric surface and resulting sinkhole development 18 

15. Graph showing pumpage at well field and water-level fluctuations in wells tapping unconfined and confined aquifers in the coastal terrane ------------------------------------------------ 19 

16. Photograph showing sinkholes and subsidence beneath and near Interstate Highway 59 in Birmingham, 

Ala., in 1972 -------------------------------------------------------------------- 21 

17, 18. Cross sections showing: 

17. Relation between water-level fluctuations and the bedrock-residual clay contact at Greenwood, 

Ala. ------------------------------------------------------------------- 22 

18. Subsurface erosion caused by water-level fluctuations resulting from pumpage --------- 23 

19. Photograph showing erosion of soil into rotted-out root opening ----------------------------- 24 

III 
20. Cross section showing subsurface erosion (piping) resulting from water-level decline------------- 25 

21-24. Photographs showing: 

21. Induced recharge forms vortex in stream in Shelby County, Ala. --------------------- 26 

22. Collapse and loss of streamflow in Shelby County, Ala. ----------------------------- 27 

23. Collapses in open area in Shelby County, Ala. ------------------------------------- 28 

24. Growth and collapse of cavity due to piping near Centreville, Ala. -------------------- 30 

25-29. Photographs showing: 

25. Collapse beneath sewage lagoon in Bibb County, Ala., in 1972 ----------------------- 31 

26. Circular fracture in asphalt ----------------------------------------------------- 33 

27. Ponding of water in depression -------------------------------------------------- 34 

28. Downward movement of signpost ------------------------------------------------ 35 

29. Construction of warehouse and office complex in area of active sinkhole development in Birmingham, Ala., in 1966 --------------------------------------------------- 37 

TABLES 

TABLE 1. Records of selected sinkholes forming in the Eastern United States since 1940 -------------- 42 

2. Sources of information used to evaluate sinkhole problems in Alabama ----------------------- 54 

FACTORS FOR CONVERTING INCH-POUND UNITS TO 

INTERNATIONAL SYSTEM (SI) UNITS 

Multiply inch-pound units 

inch (in) 

inch (in) 

foot (ft) 

mile (mi) 

square foot (ft2) 

acre 

square mile (mi2) 

gallon per minute (gal/min) 

million gallons per day 

(Mgal/d) 

pound per square foot 

(lb/ft2) 

25.4 

2.540 

0.3048 

1. 609 

0.09294 

0.4047 

2.590 

0.06309 

0.04381 

4.882 

IV 

To obtain SI units 

millimeter 

centimeter 

meter 

kilometer 

square meter 

hectare 

square kilometer 

liter per second 

cubic meters per second 

kilograms per square meter 
Development of Sinkholes Resulting from Man's 

Activities in the Eastern United States 

By J.G. Newton 

ABSTRACT 

Development of induced sinkholes in carbonate terranes in 

the Eastern United States has resulted in costly damage and 

water pollution. Previously, detailed investigations of sinkholes 

were limited to Alabama and Missouri, with the most comprehensive being in Alabama. An investigation of the remainder 

of the area was made in 1981 to regionalize previous findings. 

More than 850 sites of sinkhole development have been identified in 19 States. It is estimated that more than 6,500 sinkholes or related features have formed at these sites. Most have 

occurred since 1950. Based on information available, States 

most impacted are Alabama, Florida, Georgia, Missouri, Pennsylvania, and Tennessee. 

The total cost of damage and associated protective measures 

resulting from induced sinkholes is unknown. Costs reported 

for a limited number of sites were about $170 million-expended 

almost entirely after 1970. About $140 million were expended 

at five dams in four States and to repair or protect highways 

in two States. 

Sinkholes are of two types, natural and induced (accelerated 

or caused by man). The sudden development of both types 

results from the collapse of the roof of a cavity or cavern in 

rock, or from the downward migration of unconsolidated 

deposits into solutionally enlarged openings in the top of bedrock. The occurrence of sinkholes resulting from bedrock roof 

collapses, in comparison with the occurrence of sinkholes 

resulting from downward migration of unconsolidated deposits, 

is rare. 

Induced sinkholes are of two types: those resulting from a 

decline in water level due to ground-water withdrawals and 

those resulting from construction. Sinkholes resulting from 

water-level declines are caused by loss of buoyant support, increase in velocity of water movement, water-level fluctuations, 

and induced recharge. Most induced sinkholes resulting from 

construction are caused by the diversion or impoundment of 

surface drainage over unconsolidated deposits resting on openings in the top of bedrock. Collapse mechanisms include loading, 

saturation, and piping. 

Assessment of existing or potential sinkhole problems at a 

site requires recognition of features associated with sinkhole 

development and knowledge of triggering mechanisms that 

cause sinkholes. Natural sinkhole development is generally not 

predictable. Induced sinkhole development is predictable in 

some instances, but is predictable only in the sense that it will 

occur in a particular area. The most predictable development 

results from dewatering by wells, quarries, and mines. 

1 

Alternatives that allow avoiding or minimizing sinkhole 

hazards are most numerous when a problem or potential problem is recognized during site evaluation. The number of alternatives declines after the beginning of site development. Where 

sinkhole development is predictable, zoning of land use can 

minimize hazards. 

INTRODUCTION 

Sudden large collapses of the land surface during the formation of sinkholes in recent years (figs. 

1, 2) have focused attention on a little-understood 

geologic hazard. Few people realize that thousands 

of similar but smaller sinkholes have formed in the 

United States since 1950. Costly damage and accidents have resulted from their sudden development beneath highways, railroads, buildings, 

sewers, dams, reservoirs and other impoundments, 

pipelines, vehicles, and, in some instances, people 

and animals. Sinkholes have also resulted in, or are 

potential sources of, pollution of water supplies. 

Concern about the problem has increased with the 

growing awareness that much, if not most, active 

sinkhole development in many areas is induced (accelerated or caused) by man's activities and that 

most of these activities involve changes in the 

hydrologic environment. 

Sinkholes (also called dolines) are natural 

features that occur in carbonate terranes. These 

terranes are characteristically underlain, at relatively shallow depths, by soluble carbonate rocks 

such as limestone, dolomite, and marble. About 15 

percent of the United States is underlain by these 

rocks. The distinctive topographic features that 

develop in carbonate terranes are unique in that 

their development is accomplished by surface and 

subsurface mechanical and solutional erosion. Subsurface erosion is accomplished mechanically, just 

as it is on the surface, and solutionally when water 
FIGURE I.-Collapse forming new sinkhole in Shelby County, Ala., 1972. (Photograph by T.V. Stone.) 

dissolves the carbonate rocks. These types of erosion are responsible for the creation of sinkholes 

and cave systems throughout the World. 

Under natural conditions, the formation of new 

sinkholes during a man's lifetime is relatively rare. 

In contrast, sinkholes induced by man's activities 

are comparatively abundant. Recognition of induced sinkhole development and limited reports 

resulting from scientific investigations of it are 

confined to this century. Almost all investigations 

dealing with mechanisms or processes involved in 

induced sinkhole development have been made 

since 1950. Research on this relatively new environmental problem has been limited and local in 

nature. 

SCOPE AND OBJECTIVES 

This report is devoted almost entirely to the initial collapse or subsidence that forms an induced 

2 

sinkhole. Few reports describe this stage of sinkhole development, and those that do rarely discuss 

the triggering mechanisms. A natural collapse is 

a product of a process that can span many thousands of years. This time frame, unfortunately, can 

be reduced to hours or days by man's activities. 

Regional investigations of active sinkhole development in the United States have not been made. 

Detailed studies of recent sinkhole occurrence are 

available only for Missouri (Williams and Vineyard, 1976) and Alabama (Newton, 1976a). The 

Alabama study included natural and induced sinkholes. Most of the Alabama inventory, prompted 

by intense sinkhole activity in populated areas, 

was acquired from multiple investigations spanning more than a decade. This work, and the findings from it, were used as a basis of and a guide 

in this assessment. 

The primary objective of this report is to document and regionalize previous findings relating to 

causes and mechanisms that trigger induced sink-
FIGURE 2.-Collapse forming new sinkhole in Winter Park, Fla., 1981. (Photograph by A.S. 

Navoy.) 

hole development. Other objectives are to describe 

(1) the extent and magnitude of induced sinkhole 

problems, (2) ways of recognizing active subsidence, (3) methods of assessing a site for potential sinkhole development, including predictive 

methodology that aids in the assessment, and (4) 

alternative courses of action that will aid in minimizing sinkhole problems. 

3 

AREA OF STUDY 

The area of study is the Eastern United States. 

Within this broad area, the study is further limited 

to that part underlain at relatively shallow depths 

by soluble carbonate rocks (fig. 3). The absence of 

these rocks eliminates the possibility of sinkhole 

occurrence. 
40°-

90° 80° 

I I 

100 200 300 MILES 

100 200 300 400 500 KILOMETERS 

75° 

I 

;: 

·.·.~ 

EXPLANATION 

• 

AREAS UNDERLAIN BY CARBONATE 

ROCKS AT DEPTHS OF LESS THAN 

250 FEET 

FIGURE 3.- Area of study and distribution of carbonate rocks. 

4 
The topography within the study area varies 

from essentially flat in coastal areas and in basins 

of the Mississippi River and other large streams 

to extremely rugged in the Appalachian Mountains. Maximum relief is about 6,600 feet. Climatic 

conditions also vary widely. Although almost all 

of the study area is classified as humid, the range 

in average annual precipitation is large-generally 

from about 25 inches in Minnesota to about 65 

inches in parts of Florida and Louisiana. 

Man's principal activities within the study area 

that are associated with active sinkhole development include ground-water withdrawals and diversion or impoundment of surface water. Groundwater withdrawals from carbonate rocks are 

through many thousands of wells that provide 

supplies for domestic, agricultural, public, and industrial use. Large withdrawals are also made 

locally as part of dewatering processes necessary 

in the construction and mining industries. 

Manmade impoundments of surface water are 

very common in the study area; they vary in size 

from small ponds to major reservoirs. Many impoundments are also used to store or treat industrial process water or to process wastes such as 

sewage. Diversion of surface-water runoff from its 

natural course is extremely common; it accompanies almost all construction. 

METHOD OF INVESTIGATION 

Most data for this investigation were collected 

in 1981. The first phase of work was to obtain information on the occurrence of sinkholes in areas 

in Alabama not previously studied. This was accomplished by contacting local agencies, officials, 

and consulting firms. Sites of multiple sinkhole occurrence were examined in the field. This was 

followed by a literature search to locate previous 

findings dealing with processes or mechanisms involved in sinkhole development, and to locate sites 

of sinkhole occurrence in the remainder of the 

study area. 

The investigation of sinkhole occurrence in 

States other than Alabama was accomplished by 

contacting the primary agencies within the various 

States that would be expected to deal with the 

problem. These agencies included the Federal and 

State Geological Surveys and Departments of 

Transportation, and the U.S. Army Corps of Engineers. Other investigators in subsidence and 

related studies in carbonate terranes were also con5 

tacted. Where necessary, information was obtained by field visits. 

ACKNOWLEDGMENTS 

Appreciation is expressed to the many individuals, government agencies, and compmies that 

provided information on active subsiden ~e. Special 

acknowledgment is due C.W. Copeland, Geological 

Survey of Alabama, and S. W. Shannon and L. W. 

Lockett, Alabama Highway Department, for contributing information on sinkholes oc~urring in 

Alabama since 1976. Similar acknowleigment is 

due numerous individuals and agencier that deal 

with sinkhole problems for providing their time 

and information. These contributors and their 

agencies include the following: Dough's Wilson, 

Georgia Geological Survey; Drs. H. Gray and C. 

Rexroad, and M. Wright and S. Frushor.r, Indiana 

Geological Survey; Preston McGrain, Kentucky 

Geological Survey, and Henry Mathis, Kentucky 

Highway Department; A.D. Martin, Maryland 

Department of Transportation; J .H. Williams and 

J.D. Vineyard, Division of Geology and Land 

Survey, Missouri Department of Natural 

Resources; R. Shiver, North Carolina Dr~partment 

of Natural Resources and Community Development, and W.D. Bingham, North Carolina Department of Transportation; J. Peter Vrilshusen, 

Pennsylvania Geological Survey; D.L. Royster and 

H.L. Moore, Tennessee Department of Transportation; and Berke L. Thompson, W es+. Virginia 

Department of Highways. B.C. Spigne~, Soil and 

Material Engineers Inc., Columbia, S.C., provided 

information for South Carolina. 

Charles Cressler and William Sinclair of the U.S. 

Geological Survey are also acknowledg~d for providing their inventories on active sub~idence in 

Georgia and Florida, respectively. 

MAGNITUDE OF 

SINKHOLE-RELATED PROBLEMS 

Recent development of sinkholes hzs occurred 

in 19 of 31 States in the project area. Available 

information does not define accurately the magnitude of the problem in many areas, owing primarily to the limited nature of this investigation. 

Available information shows that the occurrence 

and impact of sinkhole development ir the study 

area has been most significant in Alabama, 
Florida, Georgia, Missouri, Pennsylvania, and 

Tennessee (fig. 4). States underlain by carbonate 

rocks that have been least affected by recent sinkhole development are located in areas affected by 

ancient glaciers (fig. 4). Most underground openings that might ultimately have caused sinkholes 

to form in these areas were either destroyed by the 

ice, filled with glacial debris, or covered with thick 

glacial deposits. 

DISTRIBUTION AND SIGNIFICANCE OF SINKHOLES 

The total number of sites of induced and natural 

sinkhole occurrence inventoried exceeds 850. Their 

locations are shown in figure 4. Because of the 

number of sites in some areas, some location symbols represent groups of sites. More than 75 sites 

in Polk County, Fla., for instance, are not shown 

because of the density of location symbols on the 

map. The number of sinkholes occurring at sites 

also varies. While single sinkholes have occurred 

at some sites, multiple sinkholes have occurred at 

others. Summaries or case histories for selected 

sites are given in table 1 (at back of report). 

Most of the estimated 4,000 sinkholes or related 

features that have occurred in Alabama since 1900 

(Newton, 1976a) are located at multiple sinkhole 

sites. The inventory for the remainder of the 

States includes more than 1,500 sinkholes. This 

total is misleading because information is not 

available to determine how many sinkholes have 

occurred at sites of intense development. At one 

location in Lehigh County, Pa. (site 4 in table 1), 

for instance, records indicate that 128 sinkholes 

formed during 1953-57 and that 25 additional 

sinkholes formed from October 1970 to January 

1971 (Pennsylvania Department of Transportation, 1971). The number of sinkholes that occurred 

between 1957 and 1970 and since 1971 is unknown. 

The number that have occurred at similar sites in 

Georgia, Maryland, North Carolina, Pennsylvania, 

South Carolina, and Tennessee is also unknown. 

HAZARDS, DAMAGE, AND POLLUTION 

The development of sinkholes commonly poses 

hazards to man. The danger depends more on 

where and how rapidly they form than on their 

size. For instance, the largest collapse in Alabama 

(fig. 1) occurred in a wooded area in 1972. Even 

though it apparently occurred very rapidly, it 

posed little hazard because of its location. In contrast, a small but dangerous collapse (fig. 5) oc6 

curred beneath a railroad in Birmingham during 

the same year. 

Only a small number of fatalities and injuries 

associated with sinkholes have been rep~rted. One 

fatality resulted from a collapse beneath three men 

at a U.S. Geological Survey test well near Keystone Heights, Fla., in 1960 (site 48 in table 1). One 

fatality and five injuries in 1968 were attributed 

to sinkhole activity beneath a bridge ov~r Anclote 

River near Tarpon Springs, Fla. (fig. 6) (J.W. 

Stewart, U.S. Geological Survey, oral commun., 

1982). Another fatality resulted in 19f 1 from an 

explosion of natural gas leaking from a pipeline in 

West Catasauqua, Pa. (site 2 in table 1), that 

reportedly was located at a site of a~tive subsidence and collapse. A tragic event als'l occurred 

in 1967 in Hannibal, Mo. Several small collapses 

occurred in depressions that formed during highway construction through limestone containing 

caves. Three boys entered a cave through one of 

the collapses and were never found (Williams and 

Vineyard, 1976). In addition to the above events, 

injuries have been reported in Alabams:t, Florida, 

and South Carolina. 

The cost of damage and measures to protect 

structures against additional or potential sinkhole 

collapse has been significant. Costs re~orted for 

a limited number of sites amounted to F'Jout $170 

million, expended almost entirely betmeen 1970 

and 1981. Of this cost, about $130 milli'ln was expended to eliminate or minimize sinkh'lle-related 

problems at five dams in Alabama, Ge<'~gia, Kentucky, and North Carolina and $10 millhn was expended to repair or protect highways ir Alabama 

and Tennessee. None of the costs reported included loss of property values, which W<''Ild be significant in many areas. Considering the magnitude 

of the problem in other areas such as Florida, 

Missouri, and Pennsylvania, available data do not 

allow a reliable estimate of the overall cost. 

All sinkholes are potential avenues of pollution 

to underlying aquifers and nearby streams. 

Because of their relation to man's water activities, 

recent collapses are common beneath sewers, 

storm drains, and sewage and industrial process 

impoundments. Collapses and the draining of 

sewage lagoons into underlying aquifers have been 

reported in Alabama (Warren, 1974) and in 

Missouri, where effluent reappeared in S:'1rings and 

wells located as much as 1.5 miles from the source 

(Aley and others, 1972). In one area ir Birmingham, Ala., nearby streams were affectEC-1 by sinkhole damage to sewers in 1963. Th~ damage 

resulted in the discharge of about 40 million 
100 

100 200 

90° 

I 

200 

300 

80° 

I 

300 Ml LES 

400 500 Kl LOMETE RS 

EXPLANATION 

• 46 SITE OR GROUP OF SITES OF 

COLLAPSE OR SUBSIDENCE 

Number corresponds to that 1n 

table 1 

• 

AREA PREVIOUSLY OCCUPIED 

BY GLACIE RS (US GEOLOGICAL 

SURVEY. 1970) 

FIGURE 4.-Locations of sites of active sinkhole development. 

7 
FIGURE 5.-Collapse beneath railroad in Birmingham, Ala., in 1972. (Photograph by B. Fitzgerald.) 

gallons per day of raw sewage into streams for 

more than 3 months while repairs to the sewer 

were made (Newton and Hyde, 1971). Similar 

sinkhole development beneath sewers, sewage 

lagoons, and industrial process impoundments has 

occurred in Alabama, Florida, Georgia, Minnesota, 

Missouri, North Carolina, Pennsylvania, and Tennessee. Examples are sites 1, 19, 20, 41, and 43 in 

table 1. 

DEVELOPMENT OF 

SUBSURFACE OPENINGS 

The physical characteristics of carbonate terranes, including the presence or absence of sinkholes in them, commonly vary from area to area 

and, within an area, from site to site. These variations require an understanding of basic processes 

such as the solution of carbonate rocks and the 

creation of subsurface openings in them. Mechanical erosion is also part of the basic process and 

8 

involves both carbonate rock and unconsolidated 

material overlying or filling openings in carbonate 

rocks. 

SOLUTION 

The solutional enlargement of subsurface openings in carbonate rocks by water occurs over 

thousands of years. This process, with the exception of the time involved, is similar to the solution 

of salt or sugar in water. Water must be acidic to 

dissolve carbonate rocks. Water becomes a weak 

carbonic acid solution (H2C03) with the addition 

of carbon dioxide (C02), a product of decomposing organic matter, as the water percolates 

through the soil zone. When it comes in contact 

with calcite (CaC03), the principal mineral in limestone, the reaction results in the conversion of 

calcite into soluble calcium bicarbonate. The part 

of the rock dissolved is then transported from the 

site by the movement of ground water. The two 

reactions described are 
FIGURE 6.-Collapse of bridge over Anclote River near Tarpon Springs, Fla., in 1968. (Photograph by J.W. Stewart.l 

C02 + H 20 (water) -+ H 2C03 (carbonic acid) 

and 

H2C03+CaC03 (calcite) -+ Ca + 2+2 HC03 - 1. 

Similar reactions occur when acidic water comes 

in contact with dolomite or marble. 

The effectiveness of acidic water as a solute is 

greatest when it first comes in contact with rock. 

Effectiveness declines as the water becomes increasingly saturated with dissolved minerals such 

as calcite. Once the water becomes saturated with 

a particular mineral such as calcite, the water will 

not dissolve any more of that mineral. For this 

reason, most solution occurs at the top of bedrock 

or in shallow existing openings in bedrock such as 

those along bedding planes, joints, fractures, and 

faults. Initially, solution-enlarged openings in 

many carbonate terranes are most common at relatively shallow depths. Over long periods of time, 

continuous solutional enlargement of openings 

9 

results in progressively increasing interconnection. 

The interconnected system of enlarged openings 

then stores and transmits even larger quantities 

of the solute (water). This progressive solution of 

carbonate rocks sets the stage for the development 

of sinkholes. 

The residue of the solution process, the insoluble part of rock not removed by solution, also plays 

an important role in the later formation of many 

sinkholes. The amount of residue varies with the 

chemical composition of the rocks involved. In 

Kentucky, the residue has been estimated to occupy about one-tenth of the space of the rock 

removed by solution (Walker, 1956, p. 23, 24). The 

resulting deposit, called residuum, commonly 

forms a mantle over the top of bedrock. This mantle consists chiefly of clay containing varying 

amounts of chert and other insoluble debris and, 

at or near its base, boulders or fragments of 

bedrock not completely removed by solution. The 

clay and other unconsolidated deposits commonly 
FIGURE 7.-Sediment-filled solutionally enlarged opening extending downward from top 

of bedrock. 

fill openings in bedrock (fig. 7). These filled openings are numerous in many terranes. 

MECHANICAL EROSION OF BEDROCK 

AND UNCONSOLIDATED DEPOSITS 

Solution-enlarged openings in the top of bedrock 

are abundant in most carbonate terranes, even 

those in which sinkholes are uncommon. They are 

the avenues through which water enters the rock. 

The presence of these openings is important in the 

development of sinkholes because they are also the 

avenues through which overlying unconsolidated 

deposits, by mechanical erosion, can migrate or be 

transported downward into bedrock openings. 

Sediment-laden water, in some instances, can also 

10 

contribute to the mechanical erosion and removal 

of bedrock by abrasion. 

Many sudden collapses forming sinkholes result 

from roof failures of cavities in unconsolidated 

deposits overlying carbonate rocks. These cavities 

are created when the deposits migrate or are 

eroded downward into openings in the top of bedrock. Their occurrence and growth has been described in the development of natural and induced 

sinkholes by Donaldson (1963), Jennings and 

others (1965), Foose (1967), Newton and Hyde 

(1971), and many other investigators. 

The typical cavity in unconsolidated deposits 

such as residual clay is circular, with the configuration of the top resembling a dome or an arch (fig. 

8A). The sides generally coincide with the occur-
(Land surface) (Land surface) 

A. Vertical enlargement B. Vertical and lateral enlargement 

EXPLANA Tl ON 

~ 

~ 

BOUNDARY DESIGNATING 

CAVITY GROWTH 

~LIMESTONE 

~ ~=3 UNCONSOLIDATED DEPOSITS (CLAY) 

FIGURE B.-Development of cavities in unconsolidated deposits. 

renee of pinnacles or irregularities in the top of 

bedrock. The walls are usually vertical as the opening grows toward the land surface. This configuration, however, can be modified by the 

configuration of the underlying openings in 

bedrock and by variations in the cohesion or competence of overlying beds. The configuration of the 

typical opening can change if its upward growth 

reaches a more competent bed. The roof flattens, 

the growth continues laterally, and the walls taper 

toward the opening in bedrock (fig. BB). These 

stages of growth in one cavity were photographed 

and observed through a small adjacent opening 

(figs. 9-11). The cavity enlargement, occurring dur11 

ing a 5-month period, resulted from the downward 

migration of unconsolidated deposits through two 

solution-enlarged openings, each 1 foot in diameter, exposed in the top of bedrock (fig. 11). An 

unusual elongated, narrow cavity, evidently 

mimicing the shape of an underlying fracture in 

the top of bedrock, was also observed in a nearby 

collapse. The competent bed causing the flat roofs 

and cavity shapes observed in this vicinity is 

residual clay that has been exposed to weathering. 

The greater resistance and toughness of this 

horizon, in relation to that of underlying unweathered residuum, has been described by Sowers 

(1956). Numerous other cavity configurations, 
FIGURE 9.-Inclined opening adjacent to cavity in residual clay in November 1970 in Bir· 

mingham, Ala. 

including horizontal tunneling along the top of 

bedrock and in associated overlying unconsolidated deposits (fig. 24), were also observed. 

CAUSES AND OCCURRENCE 

OF INDUCED SINKHOLES 

Induced sinkhole occurrence, like natural sinkhole occurrence, basically results from (1) the collapse of the roof of a cavity or cavern in rock or 

(2) the downward migration of soil and other unconsolidated deposits into openings in the top of 

bedrock. Collapses resulting from failures of rock 

roofs are rare. According to Williams and Vineyard 

(1976, p. 32) in a study involving 97 collapses in 

Missouri, "Although cavern roof collapse in bedrock has been cited as a cause of catastrophic sinkhole formation, no contemporary event that could 

12 

be attributed directly to this cause has been observed." Similar observations have been made in 

Tennessee (Moore, 1980), Alabama (Newton and 

Hyde, 1971; Newton, 1976a), and elsewhere. Of 

hundreds of recent collapses observed by the 

author, only one could be classified as a possible 

collapse of bedrock roof (Newton, 1976a, p. 15). 

Similarly, of 650 sinkholes recorded in Florida, 

only one might be a rock roof collapse, and this 

is not certain (Beck, 1984, p. x). The rarity of a 

rock-roof collapse is inferred from the fact that, in 

the many thousands of caves in the United States, 

no extensive rockfall has been recorded in historic 

times (Davies, 1951, p. 36; Davies, U.S. Geological 

Survey, written commun., 1983). 

Induced sinkholes were first classified by separating those caused by lowering the water level from 

those caused by raising the water level (Aley and 

others, 1972). This classification system was mod-
FIGURE 10.-Cavity in residual clay in November 1970 in Birmingham, Ala. 

ified by Newton (1976a), who categorized induced 

sinkholes as those caused by declines in water 

levels due to ground-water withdrawals and those 

caused by construction. Sinkholes resulting from 

construction include those caused by erection of 

structures, by impoundment or diversion of 

surface water, and by modifications of the land 

surface. Types of induced sinkhole activity identified in the States in the area of study are shown 

in figure 12. 

Most induced sinkholes result from acceleration 

of natural processes by man's activities. If these 

activities had not been undertaken, sinkholes 

either (1) would not have occurred, (2) would not 

have occurred during a man's lifetime, or (3) would, 

under natural conditions, have occurred as subsidence rather than collapse. 

Because of the impossibility of describing induced sinkhole development in the many carbon13 

ate terranes, two terranes have been selected to 

illustrate sinkhole development. For discussion 

purposes, they are identified as the "interior" and 

"coastal" terranes. Factors related to sinkhole 

development in them are generally applicable to 

other terranes. These terranes are used as examples to describe processes and (or) mechanisms 

associated with sinkhole development. 

The interior terrane is geologically and hydrologically similar to terranes observed in 11 areas 

in which intense sinkhole development has been 

examined by the author. The coastal terrane is 

similar to that in many parts of Florida and probably in some parts of South Carolina and North 

Carolina. The interior terrane is used to illustrate 

sinkhole development primarily under water-table 

conditions, and the coastal terrane is used to illustrate sinkhole development primarily under artesian conditions. 
FIGURE 11.-Composite photograph of cavity in residual clay in April 1971 in Birmingham, Ala. 

DECLINE OF WATER LEVEL 

The first recognizable sinkhole activity identified in the literature as resulting from groundwater withdrawals occurred near Sylacauga, Ala., 

when pumpage from a spring caused sinkholes onehalf mile away (Prouty, 1916). The occurrence of 

this type of activity is not restricted to Alabama. 

Sites in the Eastern United States in which similar 

sinkhole activity has been investigated or reported 

are shown in figure 12, and selected sites are 

described in table 1. 

The first scientific investigation associating the 

occurrence of sinkholes with pumping and a decline in the water table was made in Pennsylvania 

by Foose (1953). He determined that sinkhole formation was confined to areas where a drastic lowering of the water table had occurred, that their 

occurrence ceased when the water table recovered, 

and that the shape of recent collapses indicated 

a lowering of the water table and a loss of buoyant 

support. 

14 

Jennings and others (1965, p. 51) associated 

development of sinkholes with pumpage and the 

creation of cones of depression. They determined 

that sinkhole and subsidence problems increased 

where the water table was lowered. Spigner (1978) 

attributed intense sinkhole development near 

Jamestown, S.C., to a water-level decline resulting 

from pumpage, provided descriptions indicating 

loss of buoyant support, and attributed some 

downward movement of unconsolidated deposits 

to piping. Sinclair (1982) attributed similar activity 

in Florida to water-level declines resulting from 

ground-water withdrawals and identified loss of 

buoyant support and water-level fluctuations as 

contributing mechanisms. 

Subsidence also accompanies the formation of 

sinkholes due to declines in water level. In Alabama, subsidence sometimes precedes collapse. 

The downward movement of unconsolidated 

deposits into bedrock, where the strength of the 

overlying material is not sufficient to maintain a 

cavity roof, will result in subsidence at the surface 
50° -

45° -

gso 

I 

goo 

I 

85° 

\ 

\-; r o -V.- \ =<::::s._ -r i : 

\~ ' . - . -- ~; ~:~:: :"-: :;&;~ ''''~ 

100 200 300 MI LES 

100 200 300 400 500 KI LOMETERS 

80° 75° 

\ I 

FIGURE 12.-Areas of induced sinkhole activity. 

15 

70° 

I 

EXPLANATION 

• SITE OF SINKHOLE OCCURENCE 

INDUCED SINKHOLE ACTI VITY 

DECLINE IN WATER LEV EL 

CONSTRUCTION 

DECLINE IN WATER LEV EL 

AND CONSTRUCTION 
(Donaldson, 1963, p. 124). Subsidence can also 

result from consolidation or compaction due to the 

draining of water from deposits previously located 

beneath the water table (Jennings, 1966, p. 48). 

Both processes would apply to subsidence in the 

study area. 

Cited reports have associated the occurrence of 

sinkholes and subsidence with, or attributed the 

occurrence to, a lowering of the water table, and 

some have described the related development of 

cavities in unconsolidated deposits. These reports, 

however, have described only indirectly, or in part, 

the hydrologic mechanisms resulting from a waterlevel decline that cause or accelerate the development of sinkholes. These mechanisms, based on 

studies in Alabama (Newton and Hyde, 1971, 

p. 17-20; Newton and others, 1973, p. 20; Newton 

1976a), are (I) a loss of buoyant support to roofs 

of cavities in bedrock and to unconsolidated 

deposits overlying openings in the top of bedrock, 

(2) an increase in the velocity of movement of 

ground water, (3) an increase in the magnitude of 

water-level fluctuations, and (4) the movement of 

water from the land surface to openings in bedrock 

where recharge had previously been rejected. 

Schematic diagrams of the interior and coastal 

terranes illustrate water-level declines, the downward migration of unconsolidated deposits, the 

creation of cavities in them, and subsequent sinkhole development (figs. 13B, and 14B). An opening in bedrock in the stream in figure 13A has been 

sealed with a cement plug (fig. 13B), a common 

mine-dewatering practice, to prevent flooding in 

the cone of depression. 

The water level in the interior terrane (fig. 13B) 

has declined below the top of bedrock and the 

hydraulic gradient has increased to the new point 

of discharge (the pump intake). 

The cone of depression illustrated in the coastal 

terrane (fig. 14B) differs from that in the interior 

terrane. The decline in the potentiometric surface 

of the artesian carbonate rock aquifer represents 

a loss of pressure rather than a dewatering of the 

openings. Descriptions of mechanisms resulting 

from the declines in water level that initiate sinkhole development follow. 

LOSS OF SUPPORT 

Water in aquifers in carbonate terranes provides 

some buoyant support, in places, to rocks that are 

or will be potentially involved in the development 

of sinkholes. In the interior terrane (fig. 13A), sup16 

port is exerted on rocks below the water table. In 

the coastal terrane (fig. 14A), hydrostatic pressure 

exerted by the artesian aquifer provides some support to overlying rocks and water in the shallow 

sand aquifer. 

The loss of buoyant support following a decline 

of the water table in the interior terrane (fig. 13B) 

can result in an immediate collapse of the roofs of 

cavities in bedrock and unconsolidated deposits, 

or can cause a downward migration of unconsolidated deposits spanning or filling openings in 

the top of bedrock. The support exerted by water 

on a solid and, hypothetically, unsaturated clay 

that overlies an opening in bedrock, for instance, 

would be equal to about 40 percent of the weight 

of the clay. This determination is based on the 

specific gravities of constituents involved. 

Sinkholes initiated by a loss of buoyant support 

are illustrated at locations 3 and 8 in figure 13B. 

The collapse of location 3 resulted from the failure 

of the bedrock roof of the cavity. The collapse at 

location 8 resulted from the failure of the roof of 

a cavity in unconsolidated deposits that existed 

prior to the decline (fig. 13A). The loss of support 

also triggered the downward movement of residual 

clay and the creation of a cavity in the deposits 

at location 7 (fig. 13B). The development of this 

type of cavity is enhanced by the physical characteristics of residual clay, which commonly has a 

pastelike consistency and can become a mud slurry 

when saturated (Kemmerly, 1980, p. 21). The 

sloughing of wet residual clay into foundation excavations (Sowers, 1956) also reflects its limited 

cohesiveness. 

Hydrostatic pressure exerted by the artesian 

carbonate rock aquifer in the coastal terrane (fig. 

14A) provides some support to overlying sand, 

clay, and water. A decline of this pressure (fig. 

14B) resulting from ground-water withdrawals can 

initiate the development of sinkholes. This occurrence near Pierson, Fla. (site 49 in table 1), has been 

described by Rutledge (1982). Declines in the 

potentiometric surface and resulting increases in 

head differential result in loading on the confining bed and on underlying openings in or near the 

top of bedrock. 

Changes in load are best described using hydrographs of the water levels involved (fig. 15). At the 

FIGURE 13.-Schematic cross sections of interior terrane showing water-level decline and resulting sinkhole development. 

(Numbers correspond to locations described in text.) 
Sinkhole 

\ ~1 

Waterfill ed 

opening 

2 

Carbonate rock 

(Bedrock) 

/ Spring 

Sediment-fil!edopen1ng 

B. 

A. Prior tow ater-level decline 

Pumping . an d water-level decline 

17 

Perennial 

stream 
Sand 

and 

clay 

Limestone 

and 

:·:::::::::. 

Water table 

(unconfined 

aquifer) 

Potentiometric 

surface (confined 

aquifer) 

. . . .:.·.· . ..... _·. __ :._:._: :.._:.:_:.: _· .. _:._:_:_:_ :. . .. ... . . . . ·._··.·. ·.·.: ······ .... · ..·· .. ·.: :·.· .. . : : . : .: .· .. : : : ~ : . :.::_::::::::·::: · ..... . ......,... ;--..;.... _. .. 

A. Prior to decline in potentiometric surface 

Pumping 

well 

\ 

B. Pumping and decline in potentiometric surface 

FIGURE 14.- Schematic cross sections of coastal terrane showing decline in potentiometric surface and resulting sinkhole development. (Numbers correspond to locations described in text.) · 

18 
w 

(!) >-

<( <( 

a..zO 

~00:: 

:::>-w 

a..ja.. >--(/) 

..J~Z 

IzO 

t--..J 

z _j 

0 <( 

~ (!) 

_j 

w 

> 

w 

_j 

<( 

w 

(/) 

w 

> 

0 

c:a 

<( 

1--

w 

w 

u.. 

z 

_j 

w 

> 

w 

_j 

0 

10 

20 

56 

52 

48 

40 

Well depth 15 feet, 

Screened 12-15 feet 

Well depth 34 7 feet, 

Cased 46 feet 

/ Potentiometric 

surface 

Head 

differential 

0:: 

w 

I-

<( 

s _I 

36 

32 

1961 

May 1964 - total of 64 / 

new sinkholes counted 

within 1 mile 

1962 1963 1964 1965 

FIGURE 15.-Pumpage at well field and water-level fluctuations in wells tapping unconfined and confined aquifers in the coastal terrane (modified from Stewart, 1968, and Sinclair, 1982). 

19 

i 
site of the observation wells at a well field near 

Tampa, Fla. (site 51 in table 1), the depth to the 

top of the confining bed is 45 feet. Prior to pumpage, the water table and potentiometric surface 

were 4 and 9.5 feet below the land surface, respectively. The natural load or pressure exerted on the 

top of the confining bed at this site, in pounds per 

square foot, is the total weight of water and the 

overlying sand and clay in a 1-square-foot column 

extending to the land surface minus the weight 

equivalent to a similar column of water extending 

to the potentiometric surface. The column extending from the confining bed to the potentiometric 

surface is the support furnished by artesian pressure. The natural load, using a specific gravity of 

2.5 for sand and sandy clay and a porosity of 35 

percent, was calculated to be about 3,200 pounds 

per square foot. 

Changes in load on the confining bed resulting 

from declines in water levels or artesian pressure 

levels causing increased head differential were 

computed in the same manner as the natural load. 

Loads due to declines resulting from the beginning 

of pumping in 1963 and a large increase in pumpage in 1964 (fig. 15) were about 3,600 and 3,900 

pounds per square foot, respectively. These loads 

are 13 and 22 percent greater than that determined 

prior to pumpage. Following the increased pumpage in 1964, 64 new sinkholes were reported within 

a mile of the well field (Sinclair, 1982). The actual 

loads at collapse sites resulting from the declines 

may have been smaller or greater than those estimated because of factors, such as natural seasonal 

declines, that were not taken into account. 

Collapses resulting from loss of support in the 

coastal terrane are illustrated at locations 2, 4, and 

5 in figure 14B. The collapse at location 2 resulted 

from the failure of a thin bedrock roof spanning 

an opening immediately below the confining bed 

(fig. 14A). Collapses at locations 4 and 5 resulted 

from the failure of the confining bed spanning an 

opening in the top of bedrock and the roof of a cavity in the confining bed over a similar opening 

(fig. 14A). 

INCREASE IN VELOCITY 

The creation of a cone of depression in the interior terrane results in an increased hydraulic gradient toward the point of discharge (fig. 13B) and 

a corresponding increase in the velocity of movement of water. The increase in velocity has resulted in the erosion and removal of sediment from 

previously filled openings at locations 4 and 5 (fig. 

20 

13A). Collapses resulted in the formatio:"l of sinkholes (fig. 13B). 

Collapses and subsidence that occurred under 

and along Interstate Highway 59 in Birningham, 

Ala., in 1972 (fig. 16) are excellent examples of 

those caused by subsurface erosion d·te to increased velocity (Newton, 1976a). Clay-filled openings in bedrock beneath the highway (black areas 

leveled with asphalt) extend more than 50 feet 

below the top of bedrock. The water movfng rapidly through interconnected openings from highland 

areas beyond the highway to the point of discharge 

in the bottom of the adjacent quarry erryded the 

clay and caused subsidence and collaps~s at the 

surface. The muddy water discharging in the bottom of the quarry results from the d~wnward 

movement of weathered residuum from collapses 

that have just occurred. 

A decline in the potentiometric surface in the 

coastal terrane results in increased head differential (fig. 15) which increases the veloc.~ty of recharge through the confining bed. The energy of 

this movement is diffuse and would not generally 

be expected to contribute to sinkhole development. 

It can contribute to sinkhole development where 

the confining bed has been breached. The opening 

in the top of bedrock underlying thE: shallow 

sinkhole at location 3 in figure 14A is flied with 

collapse debris from the ruptured confining bed 

and overlying sand and clay. The vdocity of 

recharge under the natural head is muc"t greater 

than that through the confining bed. An additional 

increase in head differential caused by pumpage 

could increase the velocity sufficiently to transport 

the debris to a greater depth in the same opening. 

This, in turn, would allow the downwar4'f flow of 

overlying sand that would result in the collapse 

illustrated at location 3 in figure 14B. 

The significance of the contribution of increased 

velocity to sinkhole occurrence in the ccastal terrane is unknown. Treatment of the subj~ct is not 

readily available in the literature. 

WATER-LEVEL FLUCTUATIONS 

Pumpage results in fluctuations in ground-water 

levels that are of greater magnitude than fluctuations that occur under natural conditjons. The 

magnitude depends principally on the transmissivity and storage coefficient of the aquifer and on 

variations in withdrawals and recharge. In the interior terrane, the movement of water through 

openings in bedrock against overlying unconsolidated deposits causes a repeated adcition and 
FIGURE 16.-Sinkholes and subsidence beneath and near Interstate Highway 59 in Birmingham, 

Ala., in 1972. (Photograph by B. Fitzgerald.) 

subtraction of buoyant support and repeated saturation and drying. Both actions can result in the 

desiccation, spalling, and downward migration of 

the deposits, all of which create or enlarge cavities. 

These processes have been termed "erosion from 

below" because they result in the creation of 

cavities in unconsolidated deposits, cavity enlargement, and eventual collapse (Newton and others, 

1973, p. 21). 

Fluctuations of the water table against the roof 

of a cavity in unconsolidated deposits near Greenwood, Ala., in conjunction with other mechanisms, 

resulted in the formation of the cavity and its collapse (Newton and others, 1973, p. 22). The relation of these fluctuations in a nearby observation 

well to precipitation and to the contact between 

bedrock and residuum is shown in figure 17. Water 

rose against the base of residual clay three times 

during the 3-month period. 

Rapid water-level fluctuations can also cause or 

contribute to the creation and collapse of cavities 

21 

in residuum where the water table prior to pumping is above the top of bedrock (fig. 18A). The 

saturated zone is in the lower part of the residuum 

containing chert fragments and calcareous debris 

not completely dissolved by solution. Because of 

its clay content and limited permeability, the 

residuum will not yield water from storage as 

rapidly as will openings in bedrock. Large withdrawals from a nearby well cause a rapid decline 

in water level to a position below the top of bedrock while water stored in the residuum continues 

to drain into the underlying opening in bedrock. 

The drainage and accompanying erosion causes or 

contributes to the creation of a cavity in the 

residuum (fig. 18B). Repeated water-level fluctuations (figs. 18C, 18D) cause enlargement of the 

cavity. This process, as related to natural fluctuations and leakage from sewers in Missouri, has 

been described by Reitz and Eskridge (1977, 

p. 433). It could contribute to intensive sinkhole 

development like that in Rossville, Ga., and in an 
Land surface 

10 

5 

0 

__J 

UJ 

aJ 

f-UJ 

UJU 

UJ<( 

LLLL 

za:: _:::l 

.CfJ 

....Jo I UJZ 

><( 

~__J _j a:: 

UJ 

f-

<( I I 5 

30 

z 

2Cf) 

f-UJ 

<(I 

f-U 

3~-------------T--------------~------------,-------, 

~~ 

Uz 

UJa:: 

a... 

2 

1971 1972 

FIGURE 17.-Relation between water-level fluctuations and the bedrock-residual clay contact 

at Greenwood, Ala. (Precipitation data from National Weather Service.) 

adjacent area in Tennessee (site 38 in table 1), 

where daily fluctuations due to pumpage generally ranged from 25 to 45 feet and were as much as 

70 feet. 

Depending on the magnitude of water-level fluctuations, any of the collapses or cavities in unconsolidated deposits overlying the cone of depression 

illustrated in the interior terrane (fig. 13B) could 

have resulted from the above-described 

mechanism. 

Fluctuations in the potentiometric surface in the 

coastal terrane (fig. 14) result in fluctuations in 

22 

hydrostatic pressure and accompanying changes 

in load. Load on the confining bed spanning an 

opening in bedrock (location 4 in fig. 14A) increases 

when the potentiometric surface declines and 

decreases when it recovers. The slight downward 

FIGURE 18.-Subsurface erosion caused by water-level fluctuations resulting from pumpage. A, prior to decline of water 

level; B, decline, drainage from and erosion of residuum, and 

creation of cavity; C, recovery; andD, decline, drainage and 

erosion, and cavity growth. 
•••••••• WATER TABLE 

I l PERCHED WATER 

DRAINING DOWNWARD 

---~~ DIRECTION OF WATER 

MOVEMENT 

EXPLANATION 

23 

~RESIDUUM 

~ CARBONATE ROCK 

r:: . ::. ::~ WATER 
FIGURE 19.-Erosion of soil into rotted-out root opening. 

deflection of the confining bed resulting from increased loading and the rebound resulting from 

decreased loading, when the changes in load are 

instantaneous, would exert stress on potential 

shear planes and weaken the confining bed. 

INDUCED RECHARGE 

A drastic decline of the water table in lowland 

areas in the interior terrane (fig. 13B) drains openings in underlying rocks that were previously 

water filled (fig. 13A) and results in increases in 

recharge from precipitation. This recharge was 

partly rejected prior to the decline because the 

openings were water filled. The quantity of surface 

water available as recharge to a lowland is generally large because of runoff moving to and through 

it from higher areas. 

Movement of induced recharge through openings such as animal burrows or rotted-out root 

openings (fig. 19) into openings in underlying 

bedrock results in the creation of cavities in the 

24 

unconsolidated deposits. This occurs where the 

deposits overlying bedrock openings are eroded 

through the openings to lower elevations. The 

process, referred to as "piping," also results in the 

development of natural sinkholes. It is illustrated 

in figure 20. The piping process generally occurs 

where the water table, previously located above 

the top of bedrock, is no longer in a position to 

dissipate the mechanical energy of the downwardmoving recharge. Rains result in progressive cavity enlargement, which eventually results in a 

collapse. 

A surface opening and underlying cavity formed 

by piping illustrated at location 5 in figure 13B and 

in figure 20B are the same as those shown in 

photographs in figures 9, 10, and 11. The process 

is also illustrated in figures 21 and 22. Figure 21 

shows a vortex, or small whirlpool, in a stream 

caused by induced recharge entering the subsurface where openings in bedrock have been dewatered. The collapse that occurred at the site a 

few days later (fig. 22) resulted in the loss of 
A. Priortodecline B. Decline, subsurface erosion, and cavity growth 

EXPLANATION 

..,....--........_ CAVITY GROWTH 

•••••••••• WATER TABLE 

----·~ DIRECTION OF WATER MOVEMENT 

.......... ::::~WATER 

[l"";;zj CARBONATE ROCK 

l<H.UUJ RESIDUUM 

SILT-FILLED ROTTED OUT 

TREE ROOT OPENINGS 

FIGURE 20.-Subsurface erosion (piping) resulting from water-level decline. 

streamflow until the underlying opening in bedrock was sealed. 

Areas in the interior terrane especially vulnerable to collapses due to induced recharge are near 

streams that have ceased flowing because of a 

decline in the water table. Precipitation on such 

an area results in intermittent streamflow that 

discharges from the streambed into the subsurface 

and forms sinkholes (Newton and others, 1973, 

p. 21). Large numbers of collapses also occur in adjacent lowland areas during flooding. 

25 

Declines in the potentiometric surface in the 

carbonate-rock aquifer of the coastal terrane (fig. 

14B) result in induced or increased recharge from 

the shallow sand aquifer through the confining 

bed. As discussed previously, this recharge would 

be diffused and would probably not contribute to 

sinkhole development. Increased velocity accompanying the increased recharge through breaches 

in the confining bed would contribute to sinkhole 

development, however, and is described under that 

mechanism. 
FIGURE 21.-Induced recharge forms vortex in stream in Shelby County, Ala. 

OCCURRENCE AND SIZE 

Sinkhole development due to water-level declines 

in the interior terrane is confined largely to lowlands in basins containing perennial or nearperennial streams or to areas where the water table 

was above or near the top of bedrock prior to 

pumpage. The position of the water table with 

respect to the irregular residuum-bedrock contact 

prior to and during withdrawals determines 

whether the area is prone to sinkhole development. 

The activity is confined to the cone of depression, 

where the mechanisms described affect unconsolidated deposits, or, rarely, to the roofs of cavities 

in bedrock. In the Eastern United States, sinkhole 

activity due to water-level declines is confined to 

areas that generally vary in size from a few feet 

around the point of water withdrawal to about 10 

square miles (site 27 in table 1). Where the water 

table is maintained below the top of bedrock, the 

location of collapses is predictable to some degree. 

26 

Many occur where surface water concentrates or 

where man has disturbed the land surface (e.g., by 

timber removal, ditching, laying of drains and 

pipelines) sufficiently to increase the downward 

movement of recharge. In one small open area in 

Shelby County, Ala. (fig. 23), for instance, 26 of 

33 collapses are located in an area from which 

timber was removed after 1950, or are within 50 

feet of structures which include a highway, its 

drain, and a gas pipeline (Newton, 1976a). Most 

of the others are in natural drainageways and on 

the flood plain of a nearby stream. Available data 

for the interior terrane indicate that most sinkhole 

activity has been related to rainfall, especially 

deluges (Newton and Hyde, 1971, p. 18-20). 

Limited data are available relating to sinkhole 

size. Most sinkholes are described as being 

"small." Of 42 collapses described in South Carolina (Spigner, 1978), the largest was about 20 feet 

in diameter and the greatest depth was about 10 

feet. The largest of 64 collapses near Tampa, Fla., 
i 

I 

I .. 

I 

I 

I 

FIGURE 22.-Collapse and loss of streamflow in Shelby County, Ala. 

was reported to have the same dimensions. Collapses in Alabama range from 3 to 340 feet in 

diameter and from 1 to 100 feet in depth. An inventory of 243 collapses in areas in Birmingham and 

Greenwood (Newton and Hyde, 1971; Newton and 

others, 1973) showed that the average sinkhole in 

the Birmingham area was 12 feet long, 10 feet 

wide, and 8 feet deep and the average sinkhole in 

27 

the Greenwood area was about 20 feet long, 13 feet 

wide, and 7 feet deep. In Shelby County, Ala. (figs. 

1, 28), six collapses had diameters approaching or 

exceeding 100 feet. Generally, collapses with diameters ranging from 25 to 50 feet were common. 

Some observed near Sylacauga, Ala., have surface 

dimensions of 30 to 100 feet. In Hershey Valley, 

Pa., 100 new sinkholes were reported to be 1 to 20 
FIGURE 23.-Collapses in open area in Shelby County, Ala. (white areas are repaired collapses). (Photograph by T.V. Stone.) 

feet in diameter and 2 to 10 feet deep (Foose, 1969). 

Although data are limited, larger collapses have 

occurred in Pennsylvania. 

CONSTRUCTION 

The term "construction" applies not only to the 

erection of a structure but to any modification of 

the land surface and the diversion and impoundment of surface water. Diversion of drainage includes any activity that results in changes in the 

downward percolation or movement of recharge to 

the water table. These activities include removal 

of timber and drilling, coring, and augering where 

pumpage is not involved. 

Construction practices often "set the stage" for 

sinkhole occurrence. In the interior terrane, 

grading removes the upper tough or cohesive 

weathered residual soils and exposes the underlying less cohesive clay. Loading on this horizon can 

cause collapses during or after construction. This 

28 

results from placing additional weight on thinned 

roofs of existing cavities in residual clay or on 

roofs of shallow bedrock openings. The occasional 

collapse beneath heavy equipment during construction is attributable to this cause (site 21 in 

table 1). Differential compaction caused by the 

weight of a structure on unconsolidated deposits 

overlying the irregular surface of the top of bedrock results in subsidence and foundation problems. Rainfall and saturation of roofs of cavities 

in residual clay after grading can also result in roof 

failure. Sinkholes that result from grading and 

loading in the coastal terrane (fig. 14A) are probably rare in comparison to the interior terrane. Existing near-surface cavities would not be present 

in the noncohesive sand in the shallow aquifer. 

Shocks or vibrations resulting from blasting or 

other causes can also contribute to the failure of 

cavity roofs in bedrock and unconsolidated 

deposits. Some collapses identified in Missouri 

have been attributed to these causes (Williams and 

Vineyard, 1976). Similarly, shock waves or vibra-
tions from cable tool drilling may have contributed 

to sinkhole development in Florida (C. H. Tibbals, 

U.S. Geological Survey, oral commun., 1983). Tibbals reported that multiple sinkholes occurred 

after installation of surface casing to bedrock when 

wells were being deepened. This type of activity 

has resulted in a temporary ban on drilling in 

Longwood, Fla. (Sentinel Star Metro Newspaper, 

July 27, 1973). Sinkholes in the same area have 

also been attributed to well construction where 

casing was not seated in bedrock (J ammal and 

Associates, 1982, p. 10-4). 

DIVERSION OF DRAINAGE 

Sinkholes caused by diversion of drainage are 

those resulting from any concentration of drainage 

relating to man's activities that exceeds, at a site, 

the concentration occurring in the natural state. 

Included as sources of drainage concentration are 

sewers, storm drains, water lines, and similar facilities. Collapses due to leakage from these sources 

are common. Concentration of water increases the 

quantity of recharge transmitted through residuum to underlying openings and also causes 

saturation and weakening of roofs of cavities in 

unconsolidated deposits. The creation or enlargement of cavities resulting from the movement has 

been described by Newton (1976a) as being the 

same as the piping process. Moore (1980) identified 

piping as being responsible for most collapse 

failures along highways in Tennessee. 

Sinkholes that result from diversions of drainage 

are most common in areas where the water table 

is located below the top of bedrock because the 

erosive energy of water is dissipated when the 

water table is located above bedrock (fig. 20A). In 

some areas, the water table is below the top of 

bedrock during dry periods and above it during 

, wet periods. In these areas, most subsurface erosion or piping due to the diversion of drainage 

would occur during the dry season and at the 

beginning of the wet season. 

A diversion of drainage, resulting piping, and 

development of cavities and a tunnel in sand near 

Centreville, Ala. (fig. 24), have been described by 

Newton (1976b). The sand, crossbedded and containing some ferruginous cemented layers, overlies 

carbonate bedrock. The grading of a timber trail 

resulted in the diversion and discharge of water 

into a surface opening connected with an opening 

in the underlying bedrock (fig. 24A). The water 

moved downward about 25 feet and laterally about 

29 

50 feet, and discharged down through an opening 

in sandy clay to a cavity in bedrock. A cavity 

developed on top of the sandy clay (fig. 24B) and, 

with continued subsurface erosion, the route along 

which the water moved enlarged back toward the 

surface, forming a tunnel (fig. 24C). A second vertical cavity formed as the erosion approached the 

surface, and the collapse of its roof enlarged the 

opening into which water discharged (fig. 24D). 

Sinkholes caused by leakage from pipes or similar structures result from the piping process, 

saturation, and loading. Saturation causes loss of 

cohesion of the residual clays and also causes 

loading because of the additional weight of the 

water. The result is the downward migration of the 

clay into an opening and the formation of a 

sinkhole. Examples of leakage resulting in subsidence or the beginning of collapses are summarized at sites 26 and 28 in table 1. 

Drilling, angering, and coring can result in collapses where surface water gains access to uncased 

or unsealed drill holes. The piping process is generally responsible. An example is a collapse that 

occurred beneath a bridge over Piscola Creek near 

Barwick in Thomas County, Ga., in 1975 (site 42 

in table 1). An additional example where water 

gained access to a drill hole is given at site 22 in 

table 1. 

Sinkholes can also form in any terrane where 

drilling penetrates, successively, a perched sand 

aquifer, an impermeable or leaky confining bed 

such as the residual clay in the coastal terrane, and 

openings in bedrock. Where the water level or the 

potentiometric surface in the bedrock aquifer is 

lower than that in the perched aquifer, the downward drainage and transport of sand through the 

drill hole could result in a collapse or subsidence 

at the surface. Although unsubstantiated, this 

could account for some unexplained collapses 

beneath drill rigs. 

IMPOUNDMENT OF WATER 

Collapses caused by impounding water occur, in 

part, in the same manner as those due to diversion 

of drainage. The impounding of water causes 

saturation and loss of cohesiveness of unconsolidated deposits overlying openings in bedrock. 

This, accompanied by loading due to the weight 

of impounded water, can result in the collapse of 

unconsolidated deposits into the bedrock opening 

and a draining of the impoundment (Aley and 

others, 1972, p. 18). If the impoundment is located 
B. Cavity resulting from subsurface erosion 

A. Growth and collapse of cavity 

EXPLANATION: 

..--- BOUNDARY DESIGNATING CAVITY GROWTH 

__.DIRECTION OF MOVEMENT OF WATER 

D. Col lapse where water enters opening at surface 

C. Tunnel resulting from 

subsurface erosion 

FIGURE 24.-Growth and collapse of cavity due to piping near Centreville, Ala. 

30 
FIGURE 25.-Collapse beneath sewage lagoon in Bibb County, Ala., in 1972. 

where the water table is naturally below the top 

of bedrock and openings at the surface are connected with those in bedrock, a collapse can result 

from the piping process. Collapses due to saturation and piping causing the draining of sewage 

treatment ponds in Alabama have been described 

by Warren (1974). One of these is shown in figure 

25. 

The development of sinkholes by piping can also 

occur when water is impounded on unconsolidated 

deposits where the water table was originally 

above the top of bedrock. On the floor of the impoundment, water moving through openings in the 

deposits into openings in underlying carbonate 

rocks can form and collapse cavities in the 

deposits. This occurs where there is considerable 

pressure exerted by the impounded water and 

where openings in the underlying carbonate rocks 

have a discharge point outside of the impoundment at a lower elevation. The increase in water 

velocity through openings in unconsolidated 

deposits into openings in bedrock, caused by the 

pressure, would probably have sufficient erosive 

capacity to create and collapse cavities in the 

deposits. This action is probably responsible for 

the formation of some sinkholes in an impoundment on the Coosa River in Alabama (Newton, 

1976a) (site 34 in table 1). Of the numerous sinkholes occurring in this impoundment, many 

undoubtedly resulted from saturation of unconsolidated deposits, loading, and erosion and turbulence caused by increased water velocity against 

clay-filled openings in bedrock. Additional examples of sinkhole activity associated with impoundments are given for sites 14, 20, 31, 37, 41, 

and 45 in table 1. 

Sinkholes resulting from the impoundment of 

water in the coastal terrane would probably be rare 

31 
and would probably result from loading. An increase in velocity resulting from raising the water 

level, thereby increasing head differential between 

the water table and the potentiometric surface, 

might cause a collapse where a breach in the confining bed (location 3 in fig. 14A) is present 

beneath the impoundment. 

OCCURRENCE AND SIZE 

Sinkholes that result from diversions of drainage 

have occurred in most States in which active subsidence has been reported. Numerous sites have 

been inventoried in Alabama and Georgia. Sinkholes associated with highway construction in 

Missouri are due to water-related changes 

(Williams and Vineyard, 1976). Sinkholes attributable to diversions of drainage along highways in Tennessee have been described and 

illustrated by Moore (1980). Similarly, sinkholes 

forming beneath drains in Pennsylvania (site 6 in 

table 1) and Kentucky are attributed to this cause. 

About 20 sinkholes resulting from construction 

and concentration of drainage at one site in Pennsylvania have been described by Knight (1970). 

Collapses due to concentrations of water caused 

by leakage from pipes and sewers have occurred 

at several sites in Alabama. Sowers (1956) described sites of occurrence in Tennessee. Numerous collapses in Allentown, Pa. (site 3 in table 1), 

were commonly associated with leaks from pipes, 

sewers, and similar structures. 

Sinkholes that have resulted from the impounding of water have occurred in numerous States in 

which active subsidence has been reported. 

Impoundments affected extend from Florida to 

Minnesota (site 1 in table 1). Some of the large 

impoundments are in Alabama, Arkansas, 

Georgia, Kentu~ky, Missouri, and North Carolina. 

Case histories for several impoundments drained 

by collapses in Missouri have been described by 

Aley and others (1972). 

Most collapses classified here as being due to 

construction are relatively small. Most in Alabama 

are less than 15 feet in diameter; the largest surface area involved was about 60 feet in diameter 

and the greatest depth about 25 feet. The largest 

reported in Missouri was about 75 feet long, 35 

feet wide, and 25 to 30 feet deep (Aley and others, 

1972). Data for collapses caused by construction 

are not available for other areas; however, most 

are probably small, and the largest are probably 

similar in size to the largest described above. 

32 

ASSESSMENT OF PROBLEM 

Recognition of potential sinkhole problems can 

result in avoiding or minimizing damage and 

hazards involved in sinkhole development. 

Because most sinkhole activity in many areas is 

induced, identification of the cause can provide 

alternatives that will stop or minimize further 

development. Assessment of a problem or potential problem at a site requires an understanding 

of the different types of sinkholes and initiating 

mechanisms described in this report. It also requires recognition of features associated with sinkhole development, site evaluation, and an 

awareness of predictive capabilities to define 

available alternatives. 

RECOGNITION 

The physical features and range in size of collapses forming natural and induced sinkholes are 

essentially the same. Natural collapses, except in 

the more active carbonate terranes, tend to be 

relatively rare and widely spaced singular occurrences that are associated with older sinkholes. 

Many induced sinkholes, especially those resulting 

from water-level declines, are associated with other 

similar collapses and with nearby wells, dewatering quarries, or subsurface mines. 

Many induced sinkholes develop with little or no 

advance warning; others are preceded by recognizable features. Many of these features indicate 

development of some natural sinkholes. Unfortunately, some features, like the fracturing of clay 

soils that results from drying, can also be attributed to other common causes. Recognition of 

several features is sometimes necessary for 

positive identification of sinkhole development. 

These features, most described by Newton (1976a), 

are as follows: 

1. Circular and linear cracks or fractures in soil, 

asphalt (fig. 26), paving, floors, walls, and 

foundations resulting from subsidence. 

These features are often accompanied in 

buildings by jammed doors and windows. 

Loud, sharp cracking noises in or under a 

structure often accompany foundation 

damage. 

2. Formation of depressions in soil or pavement 

that commonly result in the ponding of 

water (fig. 27). 

3. Slumping, sagging, tilting, or warping of highways, rails, fences, curbings, pipes, poles, 
I • 

\ \ 

FIGURE 26.-Circular fracture in asphalt. 

sign boards, and other vertical or horizontal 

structures, including the downward movement of small-diameter vertical structures 

such as poles or posts (fig. 28). 

4. Holes that form in the ground in a relatively 

short period of time. Enlargement beneath 

the land surface is sometimes observable. 

5. Discharge of drainage into small holes or fractures in the ground that do not fill and 

overflow. Scouring or erosion around openings (fig. 19) sometimes occurs in drains and 

flood plains. 

6. Sudden muddying of water from a well that 

has been producing clear water. Occurrence 

is often associated with precipitation. 

7. Sudden draining of a well or a large decline of 

water level where there is no history of large 

declines. 

33 

8. Water spouts erupting from openings in soil 

during rainstorms in basins adjacent to 

highland areas. This occurs when underlying bedrock openings are sealed by the 

downward migration of residual clay. Subsurface recharge from a highland area temporarily discharges at the surface due to 

blockage of the cavity system. 

9. Anomalous variations in vegetative vigor due 

to lack or excess of water. 

10. Stream discharging into openings in the 

ground. Where streamflow exceeds water 

loss into the ground, small whirlpools (fig. 

21) accompanied by sucking or draining 

noises are sometimes present. 

11. Sudden draining of a surface water impoundment or inability of a new impoundment to 

hold water. 
FIGURE 27.-Ponding of water in depression. 

12. Depressions in a wooded area where collapses 

have occurred but where the root zone maintains soil and leaf cover. The ground moves 

when stepped on, and it feels as if one is 

walking on a net or sponge. 

13. Sound of running water in the subsurface being emitted through small openings at the 

land surface. 

14. Sporadic muddying or discoloration of discharge below a dam when the water in an impoundment is clear. 

SITE EVALUATION 

Most site evaluations are initiated by developers 

to assess an area for a particular land use. Others 

are made by land users after the occurrence of 

sinkholes to identify causes, to evaluate the potential for additional occurrence, or to assess damage 

and the need for repairs. Additional evaluations 

are made to obtain information for litigation or to 

identify areas prone to sinkhole development for 

insurance purposes. 

34 

Approaches, procedures, and methods used to 

evaluate sites vary greatly because of (1) the innumerable differences in geologic and hydrologic 

conditions in the many carbonate terranes, (2) 

variations in the types and magnitudes of problems prompting assessments, (3) variations in the 

land uses planned, and (4) funding and time limitations. No specific approach is recommended here 

because these factors often dictate what, when, 

and how much work is done. 

Site evaluations, while they vary in detail and 

method, basically require the same approach. An 

orderly examination of readily available information can reduce greatly the amount of field observation or work required. The primary sources are 

(1) geologic maps and reports, (2) topographic 

maps, (3) aerial photographs, and (4) published and 

unpublished water records. Information available 

from the first three sources, acquired from a series 

of investigations in Alabama (Newton, 1976a, 

p. 52-67), is given in table 2 (at end of report). 

A geologic map showing the distribution of carbonate and noncarbonate rock units aids in deter-
FIGURE 28.-Downward movement of signpost. 

mmmg whether all or part of the area being 

evaluated requires examination. It may also show 

the location of geologic structures such as faults 

and folds. Geologic reports may provide additional 

information such as the orientation of fracture 

systems, descriptions of overburden, and well logs. 

Information on topographic maps complements 

that on geologic maps. By superimposing sinkholes shown on topographic maps on the geologic 

map showing the distribution of carbonate rock 

units, a map showing areas in which sinkholes 

have occurred and can occur can be constructed. 

The concentration and alignment of sinkholes may 

also indicate orientation of bedding planes, location of faults or fractures, and areas that are least 

stable. Other valuable information on topographic 

maps includes locations of industries, mines, and 

quarries from which information can be acquired 

during field inspection. 

Aerial photography aids in locating depressions, 

small natural sinkholes, and recent natural and induced collapses not shown on topographic maps. 

Their identification, whether from photographs or 

35 

field inspection, is a necessity. Recent photography also updates or identifies land use changes 

occurring since publication of topographic maps. 

Water records can provide a basis for determining why active sinkhole development has occurred 

or is occurring, and its significance. Records for 

wells in the area may be available from Federal and 

State Geological Surveys. These agencies will also 

be aware of other potential sources of information. 

The next and often final stage of site evaluation 

is field observation, during which the findings 

from the evaluation of available information are 

verified. The site is examined for features 

associated with sinkhole development; existing 

sinkholes and depressions are examined for recent 

movement; pertinent water withdrawal and water 

level data are acquired; and a history of active 

sinkhole development in the area, if any, is obtained. Historical sinkhole data are obtained from 

interviews with landowners, county and municipal 

waterworks, street, and sanitation department officials, county and State highway engineers, 

agents with the U.S. Soil Conservation Service, 
drillers, and others. The results are generally sufficient to complete evaluations for many land uses. 

The investigator, when recommending a site for 

a particular use, should always consider practices 

that minimize the initiation of sinkholes. These include avoiding or minimizing alterations of the 

land surface and natural drainage. 

Site development involving active sinkholes (fig. 

29), heavy construction, or proposed land uses 

possibly associated with the triggering of induced 

sinkhole development will require additional information. Information includes water-level measurements and aquifer characteristics, thickness of the 

overburden, foundation adequacy, and the presence or absence of openings in bedrock and overburden obtained by drilling and pumping, augering, and coring. Sealing of test holes and wells 

drilled during data collection might prevent piping that could result in induced sinkholes (sites 22 

and 42 in table 1). 

In areas where drilling is not feasible, information is sometimes obtained with subsurface geophysical techniques such as gravity, seismic, 

electrical resistivity, and ground-penetration radar 

surveys. These surveys yield information relating 

to the overburden-bedrock interface, the location 

of caverns or large subsurface openings, and other 

anomalies that may be significant. Airborne 

remote sensing, especially multispectral photography, can also be used to identify features 

associated with active sinkhole development and 

other beneficial information (table 2). 

Evaluation of sites during and following data 

collection can determine the feasibility of that site 

for specific land uses. Some proposed uses may be 

feasible and others may present problems that, 

with engineering, are acceptable. Some sites may 

be unsuitable for their intended use. In areas that 

have been damaged or are being threatened by 

sinkholes (figs. 23, 29) or where the intended land 

use may initiate sinkhole occurrence, the site 

evaluation may require some degree of prediction 

to provide alternatives that will help avoid, stop, 

or minimize sinkhole development. 

PREDICTION 

Sinkholes resulting from man's water activities, 

in contrast to those resulting from natural processes, are predictable in some instances-but 

predictable only in the sense that they will occur 

within a particular area, not when, to what extent, 

and so forth. This predictive capability is also 

restricted to certain terranes. It would not, for in36 

stance, relate to possible sinkhole occurrence in 

most terranes altered by glaciation. Similarly, 

prediction in the coastal terrane is very limited 

because of large variations in the thickness of the 

confining bed and because of a lack of information 

relating to conditions and the amount of stress 

that initiates sinkhole development. 

Predictive capabilities are most useful for the interior terrane, with many being applicable to other 

terranes. The position of the water table in relation to the top of bedrock, for instance, determines 

whether a triggering mechanism will be activated 

by a water-level decline or whether piping can 

result from a diversion of drainage. 

Determining the position of the water table in 

relation to the top of bedrock aids in predicting 

whether sinkholes will occur. The most predictable 

sinkhole development is that resulting from waterlevel declines due to dewatering by subsurface 

mines and quarries. This occurs where the water 

level, previously located above the top of bedrock 

during all or most of the year, is maintained below 

the top of bedrock by pumping. All mechanisms 

affecting overlying unconsolidated deposits that 

initiate sinkhole development are activated by this 

decline. Conversely, unconsolidated deposits are 

not affected where the water level fluctuates below 

the top of bedrock prior to dewatering. 

Sinkhole development following dewatering by 

subsurface mining occurs more rapidly and is more 

widespread than that resulting from quarrying. 

Because of the depth of dewatering, cones of 

depression are relatively large (sites 4, 7, and 27 

in table 1). Pit quarrying begins at the top of 

bedrock, with progressive deepening occurring 

over a period of years. Sinkhole development 

begins after water-bearing openings are penetrated. When this occurs at shallow depths, 

sinkhole development is generally confined to the 

immediate vicinity. Sinkholes occur farther away 

as the cone of depression enlarges owing to the 

deepening of the quarry and the accompanying 

dewatering (Newton, 1976a, p. 23-27). 

Many sinkholes in a dewatered area will occur 

where concentrations of surface water are greatest, such as streambeds, natural drains, or poorly 

drained areas. Large numbers occur where natural 

drainage has been altered or where recharge has 

been increased as a result of activities such as 

timber removal and grading. Most occur during 

or immediately after periods of rainfall, especially deluges, when hydrologic stresses to overburden 

such as piping, saturation, and loading are 

greatest. 
FIGURE 29.-Construction of warehouse and office complex in area of active sinkhole development in Birmingham, Ala., in 1966. 

(Photograph by James Walters ~ 

Sinkhole development from dewatering by wells, 

like that from dewatering by mining, results from 

prolonged continuous pumping. Wells involved 

generally yield large supplies that periodically 

become muddy. This water may be used for purposes other than human consumption such as fire 

protection, cooling, and washing (Newton, 1976a, 

p. 74, 75) (sites 24 and 33 in table 1). Prolonged 

pumpage from new wells to "clear up" turbidity 

problems (sites 15, 30, 35, and 40 in table 1) also 

belongs in this category. 

Prediction of sinkholes resulting from pumpage 

by wells is greatly enhanced by site evaluations 

and case histories that pinpoint other activities 

and conditions that contribute to sinkhole development. Development of a high-capacity well in or 

adjacent to an area of large withdrawals where 

sinkholes have occurred or are occurring (site 38 

in table 1) would be a risk. Unusually close well 

spacing to obtain more water from a limited area 

(site 8 in table 1) would be a greater risk. Similar37 

ly, a high-capacity well located in the immediate 

vicinity of foundation auger holes (site 33 in table 

1) would have to be considered a potential problem 

owing to induced recharge and piping. Locations 

of wells near manmade impoundments (sites 39 

and 47 in table 1) also pose some risk where cones 

of depression extend to or beneath impoundments. 

The most predictable collapses due to well construction or development occur at sites where the 

water table is near land surface, saturated overburden is thin, and mud-filled openings are at or 

near the top of bedrock. During well development, 

air pressure or pumping is used to increase yields 

by removing natural accumulations of mud and 

sediment in openings in bedrock. The "mining" of 

overburden through openings connected with the 

top of bedrock is often masked by this procedure. 

The likelihood of collapses increases with the 

amount of sediment removed. Although most collapses result from shallow openings, the removal 

of large quantities of mud from openings as deep 
as 300 feet have resulted in collapses (S. Graves, 

Graves Drilling Co., Sylacauga, Ala., oral commun., 1983). 

Prediction of sinkhole development due to construction can be made in some instances. Sinkholes 

associated with major impoundments are predictable to some degree because all mechanisms 

associated with sinkhole development are triggered by this type of construction. Fortunately, 

detailed site evaluations and engineering practices 

minimize hazards to dams and allow time for corrective and safety measures where problems arise 

(sites 14, 31, 34, and 37 in table 1). 

Areas most prone to sinkhole development are 

those where the water table is located below the 

top of bedrock and overlying unconsolidated 

deposits are thin. Further thinning of overburden 

by grading would enhance piping. Areas with thick 

overburden would have lower risk, especially 

where the water table is above bedrock. This position of the water table would eliminate piping as 

a mechanism in most instances. Some sinkhole risk 

would accompany significant diversions of drainage such as irrigation or the construction of sizable 

ponds or impoundments. Alteration of the land 

surface to construct a pond in a natural sinkhole 

(site 23 in table 1), for instance, would be considered a risk. In contrast, grading to construct 

impoundments in areas without natural sinkholes 

or a history of their development might be considered acceptable, but may result in multiple collapses (site 21 in table 1). In a few instances, 

prediction is obvious. One example is the construction of a holding pond on or adjacent to numerous 

auger holes and a large-capacity well in an area 

with a history of sinkhole development (site 33 in 

table 1). In most instances, prediction is limited 

to weighing the magnitude and type of land-use 

change to be made against geologic and hydrologic 

conditions at the site involved. 

AVOIDING OR MINIMIZING PROBLEMS 

Alternative courses of action that avoid or minimize hazards associated with sinkhole development are available, in some instances, to those 

making site evaluations. Most alternatives relate 

to induced sinkhole development and their occurrence in the interior and similar terranes. To 

benefit from available alternatives, awareness of 

sinkhole or potential sinkhole activity that can be 

associated with wens, quarries, and mines is 

necessary. Alteration of the land surface in such 

an area can increase the severity of sinkhole 

38 

development. Identifying these areas during site 

evaluation allows several alternatives: select 

another site and avoid the problem, use engineering practices to protect structures and minimize 

hazards, or accept risks and potential consequences. Engineering practices used to minimize 

problems include placing foundations on bedrock, 

grouting openings in bedrock, paving parking lots, 

and diverting surface runoff through impermeable 

drains. Impermeable drains, bridging, removal of 

overburden and replacement with riprap, and installation of reinforcing steel in pavement are used 

to minimize problems in highway construction. 

Courses of action available decrease greatly 

when sinkhole problems associated with water 

withdrawals are discovered during or after construction. After initial stages of construction, 

costs of protective engineering practices could 

restrict alternatives to the management of surface 

runoff or abandonment. 

The most common alternative to minimize 

sinkhole problems that may result from groundwater withdrawals from wells is to control waterlevel declines by regulating pumping rates and 

well spacing. When these alternatives are used, 

water withdrawals by adjacent land users should 

always be considered. 

Limited alternatives are available where the new 

land use is the mining or quarrying of carbonate 

rocks or valuable minerals in these rocks or other 

rocks interconnected with them. Dewatering of 

carbonate rock quarries and mines is commonly 

accompanied by some sinkhole activity. Minimizing potential sinkhole impact is accomplished in 

most instances by locating sites in undeveloped 

areas and, where feasible, minimizing depth of 

dewatering, sealing openings dewatered, and 

grouting. Because the mining commonly continues 

for decades, many problems arise where conflicting 

land uses are developed in and adjacent to impacted areas (fig. 29). Warren (1976, p. 41) stated 

that the logical alternative to eliminate most 

hazards would be zoning that would require the 

coordination of mining companies, local planning 

agencies, and developers. Land use in and adjacent 

to impacted areas would be restricted to those less 

prone to hazards such as forests and pasture. 

Housing and other high-density development 

would be avoided. 

Alternative courses of action involving induced 

sinkholes due to construction are generally limited 

because of the lack of predictability. Where site 

evaluation indicates a degree of risk for the intended land use, there is the choice of selecting 
another site with less risk or using engineering 

practices that will eliminate or minimize the problem. Most of these alternatives or precautions 

involve foundation design, surface-runoff management, and impoundment-engineering practices 

such as compaction and lining. Where a degree of 

risk cannot be assigned, the land user's most protective measure is the minimizing of landform and 

drainage alterations. 

SUMMARY AND CONCLUSIONS 

1. Thousands of sinkholes have formed in the 

Eastern United States since 1950. Most of 

these were induced by man's activities 

changing the hydrologic environment. Collapses forming natural sinkholes are rare in 

many terranes. 

2. Sinkhole development was identified in 19 of 

31 States in the study area. More than 850 

sites were inventoried; it is estimated that 

more than 6,500 sinkholes or related 

features have occurred at these sites. Extensive inventories are available only for 

Alabama and Missouri. The Alabama inventory, the most comprehensive, was used as 

a guide in this study. 

3. Total cost of damage and associated protective measures is unknown. Costs reported 

during the limited inventory amounted to 

about $170 million, expended almost entirely after 1970. Of this, about $140 million was 

expended for protective measures at five 

dams or impoundments in Alabama, 

Georgia, Kentucky, and North Carolina, and 

to repair or protect highways in Alabama 

and Tennessee. 

4. Available information shows that the impact 

of sinkholes has been most significant in 

Alabama, Florida, Georgia, Missouri, Pennsylvania, and Tennessee. States with the 

least impact are located in areas formerly 

covered by glaciers. 

5. Loss of life resulting from sinkholes is rare. 

Fatalities resulting from or associated with 

sinkholes have been reported in Florida, 

Missouri, and Pennsylvania. Injuries have 

been reported in Alabama, Florida, and 

South Carolina. 

6. The sudden development of sinkholes results 

from the collapse of the roof of a cavity or 

cavern in rock, or from the downward migration of unconsolidated deposits into solutionally enlarged openings in tl'~ top of 

bedrock. Cavities in unconsolidated deposits 

form when the deposits migrate downward 

into bedrock openings. The occurrence of 

roof collapse in bedrock, compared with that 

of roofs of cavities in unconsolidated 

deposits, is rare. 

7. Mechanisms that initiate most natural and induced sinkholes are the same. 

8. Most induced sinkholes related to w~ter activities, if these activities had not str~ssed the 

system, either (1) would not have occurred, 

(2) would not have occurred during a man's 

lifetime, or (3) would, under natural conditions, have occurred as sub sidell ce rather 

than collapse. 

9. Induced sinkholes are separated into those 

resulting from a decline in water level and 

those resulting from construction. Construction includes erection of structures, grading, 

blasting, and any other activities that result 

in the alteration of the land surface and the 

diversion and impoundment of drainage. 

Diversion of drainage includes any activity 

that changes rates of recharge, such as the 

removal of timber and drilling, coring, and 

augering where pumpage is not involved. 

Diversion and impoundment of drainage 

account for most sinkholes resul .. ing from 

construction. 

10. Mechanisms that trigger induced sinkhole 

development resulting from a decline in 

water level are (1) loss of buoyant support, 

(2) increase in velocity of ground-water 

movement, (3) increase in mag,jtude of 

water-level fluctuations, and (4) novement 

of water from the land surface to openings 

in bedrock where recharge had r":'eviously 

been largely rejected. 

11. Mechanisms that trigger induced sinkhole 

development resulting from construction include (1) loading, (2) saturation, (3) piping, 

and (4) shocks or vibrations. Sinkholes 

resulting from shocks and vibrrtions are 

rare. 

12. Assessment of existing or potential sinkhole 

problems requires recognition o~ features 

associated with sinkhole development, site 

evaluation, and an understanding of triggering mechanisms. 

13. Most site evaluations are made to assess an 

area for a particular land use, to identify 

sinkhole development, to evaluate potential 

for additional sinkhole occurrer ~e, or to 

39 
assess damage and the need for repairs. 

Available information includes geologic 

maps and reports, topographic maps, aerial 

photographs, and water records. Field observation is made to acquire other data and to 

determine what additional information is 

needed. Additional information is commonly acquired by drilling and pumping, augering, and coring. Depending on need, 

information may also be obtained by airborne remote sensing, subsurface geophysical, and other techniques. 

14. Where and when natural sinkholes will occur 

is not predictable. Induced sinkholes resulting from water activities are predictable in 

some instances, but only in the sense that 

they will occur within a particular area. This 

predictability is restricted to certain terranes and is dependent on the degree and 

type of impact to be exerted. Prediction is 

enhanced by site evaluation and case 

histories. The most predictable induced 

development is that resulting from dewatering by wells, quarries, and mines. 

15. Alternatives that allow avoiding or minimizing sinkhole hazards are most numerous 

when a problem or potential problem is 

recognized during site evaluation. The 

number of available alternatives declines 

after site development begins. 

16. Where sinkhole development is predictable, 

zoning of land use can minimize hazards. 

SELECTED REFERENCES 

Aley, T.J., Williams, J.H., and Massello, J.W., 1972, Groundwater contamination and sinkhole collapse induced by leaky 

impoundments in soluble rock terrane: Missouri Geological 

Survey and Resources, Engineering Geology Series, no. 5, 

32 p. 

Allen, A.S., 1969, Geologic settings of subsidence, in Reviews 

in engineering geology: Geological Society of America, v. 

2, p. 305-342. 

Beck, B.F., 1984, Sinkhole terminology, in Beck, B. F., ed., Sinkholes: Their geology, engineering, and environmental impact: First Multidisciplinary Conference on Sinkholes, 

Orlando, Fla., 1984: Rotterdam/Boston, A. Balkema, 429 p. 

Coleman, A.M., and Balchin, W.G.V., 1959, The origin and 

development of surface depression in the Mendip Hills: 

Geological Association of London, Proceedings, v. 70, pt. 

4, p. 291-309. 

Court of Appeals of Maryland, 1968, George M. Finley et ux. 

v. Teter Stone, Inc., no. 335 in 248 Atlantic Reporter: 2d 

ser., p. 106-117. 

Davies, W.E., 1951, Mechanics of cavern breakdown: National 

Speleological Society Bulletin no. 13, p. 36-43. 

40 

Donaldson, G.W., 1963, Sinkholes and subsidence caused by 

subsurface erosion: Regional Conference for Africa on Soil 

Mechanics and Foundation Engineering, 3d, Salisbury, 

Southern Rhodesia, 1963, Proceedings, p. 123-125. 

Foose, R.M., 1953, Ground-water behavior in the Hershey 

Valley, Pennsylvania: Geological Society of America Bulletin 64, p. 623-645. 

__ 1967, Sinkhole formation by ground-watf~r withdrawal, 

Far West Rand, South Africa: Science, v. 157, p. 1045-1048. 

__ 1969, Mine dewatering and recharge in crrbonate rocks 

near Hershey, Pennsylvania, in Legal aspe~ts of geology 

in engineering practice: Geological Societ:r of America, 

Engineering Geological Case Histories, no 7, p. 45-60. 

Goughnour, R.D., Anderson, Robert, and DiMaggio, Jerome, 

1979, Limestone related problems on transportation 

facilities, in U.S. Department of Transporta~ion, Highway 

Focus, v. 11, no. 2, p. 1-31. 

Herrick, S.M., and LeGrand, H.E., 1964, Solution of subsidence 

of a limestone terrane in southwest Georgia~ International 

Association of Scientific Hydrology Bulletin, v. 9, no. 2, 

p. 25-36. 

Howard, A.D., 1963, The development of karst features: National Speleological Society Bulletin, v. 25, pt. 2, p. 45-65. 

Jammal and Associates, 1982, The Winter Par1l" sinkhole-A 

report to the City of Winter Park, Florida" 

Jennings, J.E., 1966, Building on dolomites in the Transvaal: 

The Civil Engineer in South Africa, v. 8, n1. 2, p. 41-62. 

Jennings, J.E., Brink, A.B.A., Louw, A., and Gowan, G.D., 

1965, Sinkholes and subsidence in the Trans"raal dolomites 

of South Africa: International Conference OJ' Soil Mechanics, 6th, Montreal, Canada, 1965, Proceedi~gs, p. 51-54. 

Johnston, W.D., Jr., 1933, Ground water in the Faleozoicrocks 

of northern Alabama: Alabama Geological f'~uvey Special 

Report 16, 414 p. 

Kemmerley, P.R., 1980, Sinkhole collapse in Montgomery County, Tennessee: Tennessee Division of Geolo~· Environmental Geology Series, no. 6, 42 p. 

Knight, F.J., 1970, Geologic problems of urban growth in 

limestone terranes of Pennsylvania: Associ ~tion of Engineering Geologists Annual Meeting, Wasl ~'lgton, D.C.r 

1970, Preprint, 16 p. 

LeGrand, H.E., and Stringfield, V.T., 1971, WatE-r levels in carbonate rock terranes: Ground Water, v. 9, no. 3, p. 4-10. 

Miller, B.L., 1941, Allentown quadrangle: Penn"ylvania Geological Survey Atlas 206, 492 p. 

Moore, H.L., 1980, Karst problems along TenneEsee highways, 

an overview: 31st Annual Highway Geolo~r Symposium, 

Austin, Tex., Reprint, 68 p. 

Newton, J.G., 1976a, Early detection and correceon of sinkhole 

problems in Alabama, with preliminary evaluation of 

remote sensing applications: Alabama Hig'lway Department, Bureau of Research and Developml'3nt, Research 

Report HPR-76, 83 p. 

__ 1976b, Induced sinkholes-A continuing problem along 

Alabama highways: International Associat~1n of Hydrological Sciences, Anaheim [Calif.] Symposium, 1976, Proceedings, no. 21, p. 453-463. 

Newton, J.G., Copeland, C.W., and Scarbrougl, L.W., 1973, 

Sinkhole problem along proposed route of Interstate 459 

near Greenwood, Alabama: Alabama Geological Survey Circular 83, 53 p. 

Newton, J.G., and Hyde, L.W., 1971, Sinkhole p~oblem in and 

near Roberts Industrial Subdivision, Birmingham, 

Alabama-A reconnaissance: Alabama Geological Survey 

Circular 68, 42 p. 
Nogushi, T., Takahashi, R., and Tokumitsu, Y., 1969, Small 

sinking holes in limestone area with special reference to 

drainage to coal mines: lASH/AIRS-UNESCO Land Subsidence Proceedings of the Tokyo Symposium, v. 2, 

p. 467-474. 

Nutter, L.J., 1973, Hydrogeology of the carbonate rocks, 

Frederick and Hagerstown Valleys, Maryland: Maryland 

Geological Survey Report of Investigations 19, 70 p. 

Pennsylvania Department of Transportation, 1971, Geological 

engineering and geophysical study: LR-1045, Section-EO!, 

Interstate 78, Lehigh County, Pennsylvania, 24 p. 

Powell, W.J., and LaMoreaux, P.E., 1969, A problem of subsidence in a limestone terrane at Columbiana, Alabama: 

Alabama Geological Survey Circular 56, 30 p. 

Prouty, W.R., 1916, Preliminary report on the crystalline and 

other marbles of Alabama: Alabama Geological Survey 

Bulletin 18, 212 p. 

Purdue, A. H., 1907, On the origin of limestone sinkholes: 

Science, v. 26, no. 565, p. 120-122. 

Reitz, H.M., and Eskridge, D.S., 1977, Construction methods 

which recognize the mechanics of sinkhole development, in 

Dilamarter, R.R., and Csallany, S.C., Hydrologic problems 

in karst regions: Bowling Green, Western Kentucky University, p. 432-438. 

Robinson, W.H., Ivey, J.B., and Billingsley, G.A., 1953, Water 

supply of the Birmingham area, Alabama: U.S. Geological 

Survey Circular 254, 53 p. 

Rutledge, A.T., 1982, Hydrology of the Floridan aquifer in 

northwest Volusia County, Florida: U.S. Geological Survey 

Water-Resources Investigations Open-File Report 82-108, 

116 p. 

Shuster, E.T., 1973, Sinkholes-A constant problem in Pennsylvania geology, in Pennsylvania Geological Survey, vol. 

4-2, p. 2, 3. 

Sinclair, W.C., 1982, Sinkhole development resulting from 

ground-water withdrawal in the Tampa area, Florida: U.S. 

Geological Survey Water Resources Investigations 81-50, 

19 p. 

Sowers, G.F., 1956, Building foundation problems in the Southem Appalachian Valley Region: American Society of Civil 

41 

Engineers annual meeting, New Orleans, La,, 1956, Preprint, 13 p. 

Spigner, B.C., 1978, Land surface collapse and ground-water 

problems in the Jamestown area, Berkley Ccunty, South 

Carolina: South Carolina Water Resources Commission 

Open-File Report 78-1, 99 p. 

Stewart, J.W., 1968, Hydrologic effects of pump~ng from the 

Floridan aquifer in northwest Hillsborough, northeast 

Pinellas, and southwest Pasco Counties, Florida: U.S. 

Geological Survey Open-File Report FL-68005. 

Sweeting, M.M., 1973, Karst landforms: New York, Columbia 

University Press, 362 p. 

Talley, J.H., 1981, Sinkholes, Hockessin area, Delaware: Delaware Geological Survey Open-File Report 14, 16 p. 

U.S. Army Corps of Engineers, 1974, Report of analysis and 

evaluations of safety earth embankment, Wolf Creek Dam, 

Cumberland River, Kentucky: U.S. Army Ccrps of Engineers, Nashville District. 

U.S. Geological Survey, 1970, Glacial geology, in The National 

Atlas of the United States, p. 76. 

U.S. Geological Survey, 1976-1977, Areas in which sinkholes 

have occurred or can occur in countries in Alabama: U.S. 

Geological Survey Open-File Maps. 

Walker, E.H., 1956, Ground-water resources of the Hopkinsville 

quadrangle, Kentucky: U.S. Geological Su:-vey WaterSupply Paper 1328, 98 p. 

Warren W.M., 1974, Retention basin failures in C"'rbonate terranes: Water Resources Bulletin, v. 10, no. 1, p. 22-31. 

__ 1976, Sinkhole occurrence in western Shelby County: 

Alabama Geological Survey Circular 101, 45 p. 

Williams, J.H., and Vineyard, J.D., 1976, Geological indicators 

of catastrophic collapse in karst terrane in Missouri: N ationa! Academy of Science, Transportation Resa.arch Record 

612, p. 31-37. 

Wilshusen, J.P., 1979, Geologic hazards in Pennsy1vania: Pennsylvania Geological Survey Educational Series 9, 56 p. 

Wood, C.R., Flippo, H.N., Jr., Lescinsky, J.B., and Barker, J.L., 

1972, Water resources of Lehigh County: P~nnsylvania 

Geological Survey Water Resource Report r 1. 
~ 

~ 

TABLE I.-Records of selected sinkholes forming in the Eastern United States since 19401 

[Site numbers correspond to numbers in fig. 4] 

Site Number of General dimensions in feet~/ 

number Source(s) of information collapses Width Length Depth 

2 

3 

4 

E. Scherbring, municipal 

employee, oral communication, 1981. 

Allentown Call Newspaper, 

January 17, 1981; unpublished data in files of 

the Pennsylvania Geological Survey 

The Morning Call Newspaper, 19+ 

Allentown, Pennsylvania, 

November 16, 1951; January 

10, 1952; and January 17, 

1952. Unpublished data 

in files of u.s. Geological 

Survey 

Miller (1941); Wood and 

others (1972); Pennsylvania Department of 

Transportation (1971); 

Longwill, Stanley M., 

u.s. Geological Survey, 

written communication, 

1961; unpublished data in 

files of u.s. Geological 

Survey. 

153+ 

10 10 20 

Descriptions 

Sewage treatment holding pond at 

into full operation about 1975. 

in the draining of effluent from 

was being evaluated by State and 

Altura, Minnesota, was put 

Collapse in 1979-80 resulted 

a 10 acre pond. Problem 

F~deral agencies in 1981. 

Development of sinkhole on January 15, 1981, at West 

Catasauqua, Pennsylvania, occurred in street beneath gas and 

water lines. A large explosion resulted in one fatality and 

heavily damaged three homes. Previous subsidence at or near 

the site reportedly damaged sewer, water and gas lines on 

April 28, 1979. Reported cost of street repair at site of 

1981 sinkhole exceeded $48,000. 

Numerous sinkholes or sites of subsidence developed in Allentown, Pennsylvania during the period 1949-52. Many occurring 

in streets or beneath structures were associated with the 

downward leakage of water from sewers, water mains, or cesspools. Sinkhole development was also associated with a large 

gas explosion and rupture of a major water main in 1949. 

Reported expenditures resulting from their occurrence exceeded $135,000. To alleviate the problem, more than 5,000 

cesspool-users were given 90 days on March 21, 1952 to 

connect their waste lines to city sanitary sewers. The 

estimated cost per user was $100 to $500 or more. 

Active sinkhole development near Friedensville, Pennsylvania 

in area of large ground-water withdrawals. Water level in 

lowland areas prior to withdrawals was generally at a depth 

of less than 30 feet. Depth to top of bedrock exceeds 30 

feet in numerous areas. Dewatering for mining was begun 

1953. Rates of withdrawal between 1953 and 1977 varied 

between 10 and 30 million gallons per day. Cone of depression in 1967 exceeded 4 square miles in size. Records 

indicate that 128 sinkholes formed around dewatering site 

during period 1953-57. Twenty-five new sinkholes occurred 

from October 1970 to Januarv 1971. Number occurring during 

the intervening 13 years and since 1971 not inventoried. 
~ 

Cl.:) 

5 

6 

7 

8 

9 

10 

Goughnour and others, 

(1979); Wilshusen (1979). 

5 

Shuster (1973); observation, 2 

photography. 

Foose (1953). 

Unpublished data in 

files of the u.s. 

Geological Survey. 

Carrol County Times 

Newspaper; December 9, 

1980. 

Court of Appeals of 

Maryland (1968). 

100+ 

7 

5 

5-40 

10 

1-20 

6-10 

11 Includes sites of active subsidence 

15-40 

10 

1-20 

6-10 

15-30 Five sinkholes developed in and near u.s. Highway 202 

adjacent to an abandoned quarry in Bridgeport, Pennsylvania, 

between January and May 1970. A temporary roadway constructed around the problem area was in use for more than 4 

years. Repairs to 1100 feet of roadway was accomplished at 

a reported cost of 2 million dollars. 

Two sinkholes formed adjacent to Highway 114 near 

Mechanicsburg, Pennsylvania, in 1973. Sinkhole in ditch 

adjacent to highway was attributed to diversion of runoff. 

Subsidence of this sinkhole required additional leveling in 

1981. 

2-10 Large increases in mine pumpage near Hershey, Pennsylvania, 

in 1949 lowered ground-water levels over an area of 10 square 

miles. About 100 new sinkholes formed entirely within the 

area where there was a drastic lowering of the water table. 

Recovery of water levels to nearly normal conditions in 1950 

was accompanied by a cessation of sinkhole development. 

3-60 Installation of well at Westminster, Maryland, in 1940 was 

associated with a collapse in the floor of a nearby building. 

In 1948, the well was replaced by two new wells located 40 

feet apart. Both wells were pumped simultaneously, one at 

500 to 550 gallons per minute and one at 450 to 500 gallons 

per minute, during a 72-hour test. Cracks reportedly formed 

in two nearby buildings at this time. On May 7, 1948, a 

sinkhole formed near the wells. Four additional sinkholes 

formed in the same vicinity in 1971. 

11 New well being developed in westminster, Maryland, in 1980 

was abandoned because muddy water could not be cleared up and 

because of the occurrence of four nearby sinkholes. An 

additional sinkhole formed in the vicinity several months 

later. 

Multiple collapses resulted in damage to 35 acres in Wakefield Valley in Carroll County, Maryland. Reported dewatering 

to depth of 80 feet. Water table in areas of collapses prior 

to dewatering was described as being at a depth of 5 feet. 

Depth to the top of rock underlying soil mantle was reported 

to vary between 17 and 30 feet. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
~ 

~ 

TABLE !.-Records of selected sinkholes forming in the Eastern United States since 19401-Continued 

Site Number of General dimensions in feet~/ 

number Source(s) of information collapses Width Length Depth Descriptions 

11 

12 

13 

14 

15 

Aley and others 

(1972, p. 12). 

Aley and others 

(1972, P• 13). 

Aley and others 

(1972, P• 17). 

u.s. Army Corps of 

Engineers (1974); 

M. Simmons, u.s. Army 

Corps of Engineers, 

oral communication, 

1981, 1983. 

c. R. Burchett, Hydrologist, u.s. Geological 

Survey, oral communication, 1981. 

2 6 

2 17 

4 10-35 

59 1-13 

34 

6 

17 

10-75 

1-15 

34 

6 Catastrophic collapse in Republic, Missouri, sewage lagoon on 

October 29, 1968, resulted in an estimated 4 million gallons 

of sewage entering ground water system during 24-hour period. 

On October 31, 1968, an additional collapse occurred. Sewage 

and dye reappeared in two wells as much as 1.5 miles from the 

lagoon. 

10-20 Collapses occurred in sewage lagoon at West Plains, Howell 

County, Missouri, in 1964 and was repaired. Collapse in 

larger nearby lagoon cell in 1966 resulted in 136 acre-feet 

of effluent draining out within 52 hours. 

6-30 Group of collapses was induced by construction at Norton Dam 

south of Winona, Shannon County, Missouri. After impoundment, four collapses occurred in or near impoundment about 

1968-69. Dam unsuccessful in producing permanent lake. 

1-10 Wolf Creek Dam on Cumberland River in Russell County, Kentucky. After 16 years of operation, wet areas materialized 

near downstream toe of dam embankment. First sinkhole was 

discovered in August 1967. Potential problem involving 

foundation seepage was recognized and detailed assessment was 

begun. Muddy flows and continuous development of sinkholes 

followed. Remedial work and continuous surveillance continued until 1972 when it was determined that course of 

action would not assure complete safety. Concrete diaphragm 

wall constructed through dam and underlying solution openings in bedrock during 1974-79 eliminated sinkhole activity 

and potential foundation problems. Reported cost 96 million 

dollars. 

18 u.s. Geological Survey test well 1.5 miles west of Dickson, 

Tennessee. Residuum about 80 feet thick, opening in limestone at depth of 172 feet, static water level at depth of 

about 50 feet. Well pumped continuously for two weeks at 

rate of 200 to 250 gallons per minute to eliminate turbidity 

(mud) problem. Two weeks after pumping ceased in May 1981, 

collapse occurred next to well during or following about 

2 inches of rain. 
~ 

<:Jl 

1b 

17 

18 

19 

Donald Rima, u.s. Geological 

Survey, oral communication, 

1981. 

J. Lovell, Murphreesboro, 9 

Tennessee, Water Superintendent, oral communication, 

January 27, 1981. 

Kenneth Gentry, Miller 

Drilling Company, oral 

communication, 1981; 

Wiley Harris, Tennessee 

Valley Authority, written 

and oral communication, 

1981; unpublished data in 

files of u.s. Geological 

Survey. 

R. Amos, Amos Construction 

Company, oral commun., 1981. 

3 

20 

8-80 

20 

5-10 

11 Includes sites of active subsidence 

20 

8-80 

20 

5-10 

2 u.s. Geological Survey test well near north limit of Franklin, Tennessee. Collapse occurred in small depression where 

discharge of about 600 gallons per minute from well ponded. 

2-10 Sinkholes in Murphreesboro, Tennessee,resulted from greater 

than average pumpage from two municipal wells during prolonged drought in 1941. Wells were 10 and 12 years old. 

Sinkhole activity ceased at end of drought accompanied by 

decrease in pumpage. Problem was avoided thereafter by regulating pumpage and water-level decline that triggered the 

previous activity. One large site of subsidence that formed 

in a street during the activity was leveled with as much as 

10 

2 feet of asphalt. Unfortunately, an underlying sewer was 

apparently broken and is believed to have been a source of 

pollution to the underlying aquifer. The problem was discovered only after a sinkhole developed at the site of the 

break about 10 years later. 

Collapse beneath sewer in Chattanooga, Tennessee,occurring in 

December 1979 exposed large cavern. One 15 foot section of 

8-inch sewer pipe missing. Located about 800 ft from new 

well being developed at rate of about 2,000 gallons per 

minute. After repairs, the sinkhole recollapsed two times in 

response to further well development and pumping test. Well 

abandoned. Well drilled to furnish Tennessee Valley Authority 

cooling system in new building. Cost of well, observation 

wells, well field design and associated engineering estimated 

to be $400,000 to $500,000. 

Pond and 2 miles of pipeline were constructed near Tuscumbia, 

Alabama in the early 1960's to remove process water from 

vinyl tile factory after nearby inhabitants objected to its 

direct discharge into streams. Immediately after first process water entered pond, collapse resulted in draining of the 

pond. A pump installed to deliver water through the pipeline 

to a distant stream when water in the pond reached a certain 

stage, was never used. The collapse, because no one objected 

to discharging the water into the subsurface, was never 

repaired. Process water was allowed to enter the collapse 

for years until the company ceased operation because of 

bankruptcy. Original construction costs of installation 

$40,000 to $50,000. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
~ 

~ 

Site 

nwnber 

20 

21 

22 

23 

24 

TABLE I.-Records of selected sinkholes forming in the Eastern United States since 19401-Continued 

Source(s) of information 

Number of 

collapses 

J. Bond, oral communication, 4+ 

1981; R. Amos, Amos 

Construction Company, oral 

communication, 1981. 

P. Moser, Geological 2 

Survey of Alabama, 

oral communication, 1982. 

w. Warren, Geological 

Survey of Alabama, written 

communication, 1976; c. R. 

Bossong, u.s. Geological 

Survey, oral communication, 

1981. 

T. Moffit, oral communica- 3 

tion, 1981; F. v. Meter, 

written communication, 1981; 

Birmingham News, 

November 24, 1981. 

Observation; unpublished 50 

data in files of u.s. 

Geological Survey. 

General dimensions in feet21 

Width Length Depth Descriptions 

2-20 2-20 

5-10 5-10 

15 15 

8-16 8-16 

1-50 1-50 

8 

15 

6 

Two 5-acre cells of a sewage lagoon were constructed near 

Leighton, Alabama in late 1960's. Collapse draining first 

impoundment occurred about 1970-71. After repair, repeated 

collapses draining first cell continued for 2 to 3 years. 

Repairs were made following each collapse. Pipelines were 

then diverted to second cell which had not been used previously. Similar collapses resulting in draining occurred 

in the second cell. System was abandoned about 1976-77. 

Estimated cost of repairs and loss $115,000. 

At old airport west of Courtland, Alabama. Collapse occurred 

under large pan during excavation of sewage lagoon. Another 

collapse occurred nearby at a later time. Both resulted from 

collapse of roofs of cavities in unconsolidated deposits. 

No evidence of natural subsidence in area. 

Drilling of new well begun near Madison, Alabama on February 

10, 1976 was discontinued when bedrock at a depth of 50 feet 

was encountered. Drill rig was left on uncased open hole. 

Heavy rain on following day, which prevented further 

drilling, ponded and entered the drill hole. On the morning 

of February 12, the c~ill rig was found in a collapse that 

occurred during the night. ' 

4-18 Fishing lake constructed in natural sinkhole near Triana, 

Alabama. After grading, three collapses occurred. Collapses 

were treated and walled off from area to be impounded. Construction was completed, water impounded, and lake was dedicated on November 23, 1981. 

<10 Wooded swamp area along planned corridor of Interstate Highway 59 near Brighton, Alabama. Area of active subsidence in 

1974. Number of sinkholes estimated. Most were small with 

surface dimensions less than 15 feet, largest was general 

area of subsidence. Activity confined to circular area with 

diameter of about 1,000 feet with an industrial well located 

at the center. The well reoortedlv was 109 feet deep and was 

pwnped 24 hours per day at 600 to 700 gallons per minute. 
~ 

-.1 

25 

26 

27 

28 

29 

Newton (1976a). 

B. Bailey, oral communication, 1974; R. Kelly, oral 

communication, 1974; 

observation. 

46 

Newton (1976a); Warren, 

1976. 

1000 

Earnest Bailey, oral 

communication, 1974. 

s. Graves, Graves Drilling 

Co., written communication, 

April 1, 1975. 

60-70 

1-300 

20 

6-8 

11 Includes sites of active subsidence 

60-70 

1-325 

20 

6-8 

o.5-1 

Repetitive photography used to illustrate migration of 

collapses-away from dewatering operation at Pelham, Alabama. 

One possible collapse observable during early stage of 

dewatering in 1950; 11 open collapses observable in 1959; 

and 34 open collapses observable in 1967. Total distance of 

migration about 0.4 mile. Distinct hazard to highways, 

structures, and a railroad. Damage not inventoried. Sinkhole activity ceased with cessation of pumpage and recovery 

of water level prior to 1967. Industrial and urban complex 

built on former area of sinkhole activity after 1967. 

Significant subsidence at Montevallo, Alabama bounded by 

radial fractures occurred on November 4 and 6, 1974 resulting 

in damage to one unit of housing project. Leakage from 

damaged fireplug discharged into ground beneath sidewalk 

inside of area of subsidence for a period of about three 

months prior to collapse. Small root-like openings in soil 

zone reported when area was graded off during construction 

of housing unit. 

1-100 Estimated number of collapses west of Calera, Alabama include 

sites of subsidence, fracturing and significant piping. Area 

dewatered by wells, quarries, and an underground mine. Cone 

of depression in October 1973 was about 10 square miles in 

size. Pumpage at that time exceeded 14,000 gallons per 

minute. Significant sinkhole development began about 1964. 

Greatest hazards in rural area were collapses beneath 

highways and major gas pipelines. Part of area still active 

in 1981. 

<1 

42 

General subsidence beneath home and patio near Calera, Alabama resulted in large fractures in concrete and inside and 

outside walls. Occurred during extended period of drought 

but attributed to long term leakage from corroded water line 

leading to home. Leakage from small openings in pipe 

entered bottom of covered ditch 25 feet from home, moved 

downslope through the ditch, and entered the subsurface 

beneath it. Total failure of pipe occurred in March or April 

1981 resulting in the discharge of water at the land surface 

in the front yard. 

Collapse 45 feet from a new public supply well near Calera, 

Alabama during initial development and pumping test. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
~ 

00 

TABLE I.-Records of selected sinkholes forming in the Eastern United States since 19401-Continued 

Site Number of General dimensions in feet 21 

number Source(s) of information collapses Width Length Depth 

30 

31 

32 

B.C. Spigner, Geological 

Survey of Alabama, written 

and oral communications, 

1972 and 1981; observation; 

photography. 

A. B. Martin, city of 

Birmingham, written 

and oral communication, 

1976 and 1981; observation. 

Powell and LaMoreaux 

(1969); J. Palmer, oral 

communication, 1981. 

13+ 4-10 4-20 4-8 

4 

Descriptions 

In July-August 1972, public supply well at Moody, Alabama, 

muddied up and failed. This occurred while new well located 

about 1,200 feet away was being developed. The former had a 

history of "mud" problems. The latter, drilled in 1971, 

required pumping for more than a year before mud problem 

cleared up. Water table and top of pinnacled bedrock near 

land surface. Collapses and subsidences started about the 

same time as the failure of the older well. They occurred 

beneath driveway, drain, culvert, homes, and yards. Two 

homes vacated. Estimated damage $75,000. 

Lake Purdy in Shelby and Jefferson Counties, Alabama. 

Concrete darn and lake were constructed in 1909. As part of 

corrective measures to eliminate leakage in 1916, clay 

blanket was placed on upstream face of dam. Between 1916 and 

1927 failures in blanket resulted from burrowing crawfish. 

Dam was raised in 1927 and grouting was accomplished to 

minimize leakage. Two sinkholes in the lake were discovered 

in 1954. Another was discovered later in the land surface 

near the dam. In December 1974, leakage became muddy and 

increased. Two sinkholes formed in the land surface near the 

north end of the dam in 1976. Grouting program was begun in 

1979 to eliminate leakage and associated problems. Program 

was highly successful. Leakage was reduced from about 4,400 

to 70 gallons per minute. Reported cost was $550,000 to 

$600,000. 

Multiple sites of subsidence and collapse at Columbiana, 

Alabama in 1968 damaged several buildings, numerous units in 

a housing project, a concrete filter plant, endangered an 

elevated water storage tank, broke water lines, and severed 

tracks of a railroad. Related occurrence to water levels, 

pumpage, and muddying of withdrawals. Suggested discontinuing pumping of all wells in area of subsidence. Replacement of municipal well system in 1969 reportedly cost 

$180,000 to $200,000. Problem ceased with corrective action. 
~ 

(.0 

33 

34 

35 

Observation; w. B. Clow, 

Clow Corporation, oral 

communication, 1972; 

photography; unpublished 

data in files of u.s. 

Geological Survey. 

4 

Alabama Power Company, 150+ 

written communication, 

1981; J. Weinfordner, oral 

communication, 1981; the 

Birmingham News, November 

25, 1979; observation. 

Unpublished data in files 

of u.s. Geological Survey; 

observation; photography. 

3 

5-18 

12-16 

11 Includes sites of active subsidence 

5-18 

12-16 

15+ Extensive augering at industrial site in Lincoln, Alabama in 

1966. Development moved to adjacent site due to potential 

foundation problems. Development of well at site in 1967 

resulted in a collapse next to it. Collapse repaired and 

holding pond was excavated next to well in area on or adjacent to auger holes. Well supplied about 300 gallons per 

minute to pond. Water circulated from well to pond and back 

to well through openings in overburden. Cessation of pumpage 

would result in draining of pond. Collapses in and around 

pond and well due to piping occurring in 1972 were repaired 

and walled off from remainder of pond. Process water used by 

industry muddied occasionally. 

Logan Martin dam used for power generation on Coosa River 

near New London, Alabama was completed in 1964. "Boils" or 

leakage appeared downstream as impoundment was being filled. 

A "chimney" sinkhole appearing in east dike of dam on April 

9, 1968 was repaired immediately. Sinkholes forming in 

impoundment were filled with more than 185,000 tons of sand, 

gravel, and stone during the period October-November 1968. 

Initiated grouting and surveillance program in March 1972 to 

minimize and monitor problem. A "bolster" or second dam was 

built behind parts of the original dam to eliminate potential 

problems. Regular computerized sonar surveys locate collapses beneath impoundment. These are filled with stone 

deposited by barge. Cost of repair and safety measures prior 

to 1980 reported to be 19 million dollars. 

2-18 Test well drilled in Childersburg, Alabama in 1969. Top of 

bedrock was 33 feet below land surface, static water level 

was 22 feet below land surface. Continuous pumping for 5 

months failed to clear turbidity. Well reconstructed in 

1972. Continuous pumping at 280 to 393 gallons per minute 

from October to November 1972 with maximum drawdown of 137 

feet. Sinkholes within 400 feet of well reportedly formed 

in October 1971 and in October and November 1972. Collapses 

occurred in street and beneath railroad. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
C1 

0 

TABLE I.-Records of selected sinkholes forming in the Eastern United States since 19401-Continued 

Site Number of General dimensions in feet21 

number Source(s) of information collapses Width Length Depth Descriptions 

36 

37 

38 

G. Swindel, u.s. Geological Survey and Alabama 

Geological Survey, written 

and oral communication., 

1956 and 1981; unpublished 

data in files of u.s. 

Geological Survey. 

J.H. Bryan, J. McFadden, 

and J. Baer, u.s. Army 

Corps of Engineers, 

Mobile District, oral 

communications, 1981. 

40 

60+ 

R. Clarke, President, and 18+ 

J. Taylor, Rossville 

Development Company, 

Incorporated, oral communication, 1981; R. Cressler, 

u.s. Geological Survey; 

unpublished data in files 

of u.s. Geological Survey. 

4-10 4-10 

2-35 2-100 

1-5 

As many as 40 collapses forming sinkholes in downtown Sylacauga, Alabama occurred during a prolonged drought in 1953-

56. The largest was as much as 30 to 40 feet in diameter 

and 30 to 40 feet in depth. Collapses occurred under 

streets, water lines, drains, and other structures including 

a church and football field. Activity ceased with recovery 

of water table at end of drought. Limited activity occurred 

briefly in 1981 during similar decline in water table. Some 

water withdrawals contributed to declines during both 

periods. 

The formation of sinkholes occurred during 1967-81 in the 

vicinity of Walter F. George Lock and Dam on the Chattahoochee River near Fort Gaines, Georgia. Five or more sinkholes 

generally form each year in downstream areas within 600 feet 

of the dam. In contrast, one sinkhole generally forms every 

two years in upstream areas within 600 feet of the dam. The 

sinkholes result from leakage from the impoundment to downstream areas. Grouting has minimized the problem. The first 

segment of a concrete sleeve to be constructed through the 

dam and carbonate rocks to insoluble rocks to eliminate 

problem is scheduled for 1982. Estimated expenditures on the 

problem and expenditures on the first segment of the sleeve 

are estimated to be about 8.6 million dollars. 

3-79 Sinkholes formed in Rossville, Georgia, and adjacent area in 

Tennessee during 1978-80. Large ground-water withdrawals 

associated with problem. Numerous small sinkholes not 

included in inventory. Fluctuations in water level during 

early part of period, based on those recorded in u.s. Geological Survey test well, generally ranged from 10 to 70 feet 

per day. During latter part of period, reduced pumpage 

resulted in fluctuations generally ranging from 25 to 45 feet 

per day. Largest collapse involved four segments of a warehouse in Tennessee. Damage was estimated to be 1.4 million 

dollars. Daily "surges" or fluctuations in water level 

0~~~~~~~ in ~0ll~~~~ ~~~0~t~~ t0 ~~n~~ ~tw~~n 1S ~n~ 10 f~~t. 
01 

...... 

39 

40 

41 

42 

43 

Vernon Rogers, u.s. Soil 

Conservation Service, oral 

communication, 1981. 

Mrs. Robert White, oral 

communication, 1981. 

D. Wilson, Georgia Geological Survey, written 

communication, 1981; 

T. Driggers and 

Associates, oral communication, 1981; observation. 

A. Maxwell, Thomas County 

Highway Superintendent, 

oral communication, 1981; 

D. Wilson, Georgia Geological Survey, written 

communication, 1981; J. 

Freeman, property owner, 

oral communication, 1981; 

photography. 

R. Shiver, North Carolina 

Department of Natural 

Resources and Community 

Development, written 

communication, 12-1-81. 

4 

25 

7+ 2-10 

35 

1-24 

11 Includes sites of active subsidence 

25 

2-10 

40 so 

1-30 2-8 

Impoundment at Chatsworth, Georgia, constructed about 1974. 

New well was located near site to supply water. Collapses 

occurred during or after filling. Stopped pumping for 

repair. A collapse occurred beneath a construction vehicle 

during repair. After filling and compacting collapses, 

impoundment was filled with water. No problems have been 

experienced since repair. Attributed collapses to well 

pumpage. 

New well 

yielded 

charge. 

night. 

drilled near Rockmart, Georgia about 1946. It 

muddy water and was pumped overnight to clear up disCollapse occurred in backyard near home during the 

Estimated that 15 truckloads of fill were used to 

level area. 

Sewage lagoons at Fort Gaines, Georgia drained into subsurface through a collapse in 1974. Repeated collapses necessitated repairs on several occasions. Abandoned. Cost of 

facility was about $100,000 and cost of replacement treatment 

system was about $230,000. 

Collapse beneath bridge over Piscola Creek near Barwick, 

Georgia in 1975. Two-inch foundation hole was cored in 

intermittent streambed to a depth of 85 feet. Based on 

reported data for nearby well, the water table should have 

been at a depth of about 120 feet. No openings were 

penetrated in the core hole. Property owner discovered large 

whirlpool or vortex "making noise" in creek 3 days later. On 

fourth day, sagging bridge and the stream discharging into 

small collapse were discovered. Steady growth of opening and 

collapse of bridge into it were observed on same day. 

Leveled collapse and relocated stream and bridge to avoid 

area. 

Collapse in lagoon at poultry processing plant between Rose 

Hill and Magnolia, North Carolina, occurred on July 20, 1974. 

About 5.4 million gallons of wastewater drained into the subsurface and discharged as a spring in a quarry wall about 

200 feet from the lagoon. The rate of discharge was estimated to be 1,000 gallons per minute. The quarry, mined for 

aggregate, was about 40 feet deep. Collapse was excavated to 

bedrock and sealed with clay. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
Ol 

t-o:) 

TABLE I.-Records of selected sinkholes forming in the Eastern United States since 19401-Continued 

Site Number of General dimensions in feet~/ 

number Source(s) of information collapses Width Length Depth Descriptions 

44 

45 

46 

47 

48 

w. D. Bingham, North 

Carolina Department of 

Transportation, written 

communication, 1981; 

R. Shiver, North Carolina 

Department of Natural 

Resources, written and 

oral communication, files 

of u.s. Geological Survey. 

R. Siesem and E. Titcomb, 

u.s. Army Corps of 

Engineers, oral communication, 1981; H. LeGrand, 

written communication, 

1977; c. Davis, oral 

communication, 1981. 

Spigner ( 1978). 

B. c. Spigner, Soil and 

Material Engineers, 

Incorporated, written 

communication, 1981. 

J. Cagle, oral communication, 1981; J. Foster, 

oral commnnica.tion, 

1981-83; photography. 

18+ 

8+ 

42 

4+ 

4-30 4-40 

1-19 1-25 

20 20 

1-18 Sinkhole activity occurred along planned highway corridor 

near Castle Hayne, North Carolina in 1980-81. Sites of 

occurrence were under pavement of existing road and in or 

adjacent to right-of-way near dewatered quarry. Four 

occurred during torrential rains in August 1981. Estimated 

cost of planned protective measures including construction 

of impermeable drain along new highway was $700,000. 

Boiling Springs Lake, North Carolina. Lake with 310-acre 

surface area impounded behind earth fill dam. Construction 

completed in 1961. Repairs made in 1964 and 1969 to plug 

sinkholes in lakebed. Sinkhole in upstream slope of dam 

partially drained lake in 1976. Problem posed a hazard to 

a railroad downstream from dam. Sinkholes also occurred in 

and near railroad route in vicinity. Cost of repairs and 

(or) safety measures to lake and dam, including grouting, 

reported to be $168,000 and those for railroad reported 

to be about one million dollars. 

1-10 Ground-water withdrawals from two quarries in the Jamestown, 

South Carolina area resulted in 42 sites of subsidence and 

collapse in 1976-78. Pumpage was estimated to be periodically in excess of 36 million gallons per day causing a waterlevel decline of over 35 feet. About 20 feet of unconsolidated sands and clays overlie the cavernous limestone being 

mined. 

15 

Two pond failures and collapses on residential property 

occurred at Santee Lakes Resort northeast of Moncks Corner, 

South Carolina. Collapses occurring in 1978 were attributed 

to ground-water withdrawals from wells. 

Collapse at u.s. Geological Survey test well near Keystone 

Heights, Florida, in 1959-60 buried drillers' helper to 

~~rth 0f 10 f~~t ~n~ r~rti~lly ~1ri~~ g~0l0gist. nrilling 

at time was at depth of about 80 feet near contact between 

surficial and underlying limestone aquifers. Water level in 

shallow aquifer reportedly higher than that in underlying 

aquifer. Well being drilled was replacement for another 

recently completed and abandoned well located about 12 feet 

away. Blasting in abandoned well to increase yield had 

damaged bottom of casing set at depth of about 80 feet. 

Casing was removed prior to drilling of new well. 
01 

CJ.:) 

49 

50 

51 

Rutledge ( 1982) • 

Observation: Jammel 

and Associates (1982); 

J. Litton, H. Owens, and 

other City of Winter Park 

officials, oral communications, 1981. 

Sinclair (1982) 

9 

350 

115+ 

11 Includes sites of active subsidence 

350 100 

Collapse forming sinkholes near Pierson, Florida occurred 

during period 1973-79. All sinkholes formed in cone of 

depression created by ground-water withdrawals. Most are 

known to have occurred during periods of drawdown caused by 

irrigation for freeze protection. The remainder formed in 

secluded locations but were discovered soon after periods of 

freeze protection. 

Sinkhole formed at Winter Park on May 8-13, 1981 (fig. 2). 

Occurred beneath home and other buildings, water mains, 

streets, automobiles and swimming pool. Occurred during a 

major drought when water levels in observation wells in general area reached record lows. Declines resulted from longterm less than average precipitation and pumpage. Top of 

carbonate rocks is at a depth of about 150 feet. Wells within a mile of the site tapping openings about 450 feet below 

this horizon yield as much as 3,300 gallons per minute. 

Water related activities and changes at site were restricted 

to those involving the swimming pool. Leakage from the pool 

occurred during the preceding year and it was filled on date 

of collapse. Between May and October 1980, leakage amounted 

to about 16,250 gallons per day. Borings through floor of 

pool located small 4-inch void resulting from compaction of 

sand caused by leakage. Cost of damages, services, and 

safety measures estimated to range between 2 and 4 million 

dollars. 

Sinkhole activity resulting from ground-water withdrawals 

occurred at six sites in same general area near Tampa, 

Florida. The largest number occurred when pumpage in a well 

field was increased from about 5 to 11 million gallons per 

day in March 1964 and, ultimately, to 14 million gallons per 

day in April 1964. By May 1964, landowners reported 64 new 

sinkholes within a 1-mile radius of well field. 

~/ Ranges represent minimum and maximum dimensions in area of multiple collapses. 
Ol 

~ 

* ;; 

~ 

~ ~ 

I 

~ 

:01 

[;] 

~ 

1:3 

~ 

TABLE 2.-Sources of information used to evaluate sinkhole problems in Alabama. 

[Modified from Newton, 1976a, p. 76, 77] 

Standard 

u.s. Department Multispectral 

of Agriculture photography 

Information needed to Geologic Topographic photography scale 1:6,000 

evaluate problem map map scale 1 :~00 or less Remarks 

Distribution of geologic units 

containing carbonate rocks. 

Geologic structures 

(faults). 

Location and size of natural 

sinkholes. 

Location and size of induced 

sinkholes and small unmapped 

natural sinkholes. 

Linear trends along which most 

sinkhole activity has occurred. 

Linear features ind~cating 

locations of unmapped geologic 

structures (faults, joints, or 

fractures). 

Water loss where streams 

discharge into ground. 

Vegetative stress or 

anomalous vigor in open areas. 

Scour holes or other small 

open~ngs in so~l zone. 

"Tree kills" or vegetative 

stress in wooded areas where 

induced sinkholes are occurring. 

Filled sinkholes and areas of 

subsidence in and along highways, 

st>:~'2ts, :t.n-1 -::t.il-:-:~:t.-is that 1):~."'2 

required leveling. 

Location of nearby industries, 

quarr~es, and mines. 

X 

X 

X X 

X 

X X 

X 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Defines area in which s~nkholes can occur. 

Generally associated with solut~onally 

enlarged openings ~n subsurface. 

Defines potent~al problem areas and ~atribution of existing sinkholes. 

Defines a problem area and distr~bution of 

active sinkhole development. Best results 

obtained from low alt~tude photography. 

Alignment of sinkholes ~ndicates areas most 

prone to their development where solut~on 

of carbonate rocks in subsurface has been 

greatest. 

Indicates where openings may exist ~n subsurface where the movement of ground water and 

solution of carbonate rocks is or has been 

signif~cant. Depending on magn~tude and 

nature of structure, high altitude photography may yield best results. 

Generally associated with development of 

sinkholes. Best results from remote sens~ng 

are obtained during the nongrowing season. 

May indicate potent~al s~te of collapse ~n 

area of induced sinkhole development. 

Associated with active development of s~nkholes. 

Potential location of sites of collapse 

obscured by vegetative cover. Where cav~ty 

in subsurface has developed and root 

damage and weaken~ng of trees has resulted 

in infestation by insects, th~s may ~nd~­

cate potential site of collapse. 

Locates problem area. 

Potential sites of large ground water w~thdrawals that may make area prone to the 

development of ~nduced s~nkholes.