Austin Caverns Report
Data Report DR-15-10
September 2015
Cover: UT Grotto cavers Mackie Brown and David Stauffer descend the 30 feet shaft of
the original quarry entrance of Austin Caverns. From Austin Statesman February 6, 1952,
article archived at Austin History Center. Photo by UT Grotto caver Carroll Slemaker.
Acknowledgements
Special thank you to the Austin History Center and the Texas Speleological Survey for
assistance with this research.
Direct information was provided by persons who have been in the cave; Katie Arens, Lee
Jay Graves, William Russell, David Locklear, Sylvia Pope, and Nico Hauwert, in
addition to written descriptions and maps referenced in this report by other cavers.
Additional information and research was provided by Yazmin Avila, Heather Tucek, and
Drew Thompson of City of Austin Watershed Protection Department Cave Team, as well
as Katie Arens, Jerry Atkinson, Gill Ediger, Carl Kunath, Bill Mixon, David Locklear,
William Russell, and Ron Ralph.
Austin Caverns Report
Data Report DR-15-10; September, 2015
Justin Shaw and Nico Hauwert, Ph.D., P.G #5171
City of Austin
Watershed Protection Department
Environmental Resource Management Division
Introduction
This report seeks to compile available historical information on Austin Caverns and its
surrounding area. A manhole cover and storm water inlet drains into the cave between
3605 and 3607 Meredith Street. The Austin Caverns study area is defined as centered on
either side of Meredith Street between Raleigh Avenue, Rockmoor Avenue, and the
extension of Stevenson Avenue (Figure 1). Information sources include Austin History
Center files, Texas Speleological Survey files, City of Austin contracted reports,
historical U.S. Geological Survey surface topographic maps (1896, 1926, and 1955), and
interviews with cave explorers who have entered the cave. Figure 2 shows portions of the
1955 USGS topographic map for the study area. This investigation focuses on the history
of the cave, as well as observations relating to cave features, extent, and stability. The
goal of this investigation is to collect information to be used to address concerns
associated with development over a large cave and sinkhole. These concerns include
surface flooding, disturbance of surface infrastructure, catastrophic sinkhole collapse,
leakage of utility lines, contamination of the Edwards Aquifer, and loss of a unique
historical feature.
1
2
Relating Cave Passages to Surface Geography
Caves are generally mapped by measuring the compass direction (azimuth), distance, and
rise or fall (inclination) between line of sight survey points starting from the entrance to
the end of the cave. Cave maps of the passages north of Meredith Street (north passages)
mapped by Carl Clayton in 1941 (Appendix A) and passages south of Meredith Street
(south passages) mapped in 1972 by William Russell, Carol Russell, Craig Bittinger, Ron
Fieseler, and John Steele (Appendix A) were geographically referenced (georeferenced)
and overlain with aerial photographs.
The location of the entrance to Austin Caverns in both the 1941 and 1972 cave maps
were assumed to be the current location of the manhole over the storm sewer standpipe.
The manhole was not professionally surveyed for this study. Instead, the state plane
coordinates for the manhole cover from City of Austin utility coverages were used: X:
3102652 feet; Y: 10081803 feet. The datum used is State Plane, NAD1983, US Survey
(feet); Central Texas 4203.
Since the azimuth is measured using a compass, the map must be rotated from magnetic
north to true north (magnetic declination). Values of magnetic declination vary over time
with changes in the earth’s magnetic field.
According to historical magnetic declinations calculated by National Oceanic and
Atmospheric Administration (Historical Magnetic Declination May 2013):
in 1940, Austin had a magnetic declination of 9.8 degrees east
in 1970, the magnetic declination for central Austin was 8.5 degrees east
A grid oriented to true north was drawn on the cave maps, and coordinates for the end of
the cave were measured as x and y coordinates relative to the entrance coordinate. The
cave maps were then added to ArcGIS software map and georeferenced relative to the
associated points. A feature class was created to trace the cave walls from the
georeferenced cave maps. The subsurface cave footprint is mapped on Figure 2. A profile
view was created on the depths of the cave floor and ceiling heights from the cave maps
(Figure 3). The accuracy of the cave maps is not known and can in other cases be verified
by re-surveying the cave or using a cave radio survey to locate specific points in the cave
from the surface. However, no verification was conducted since the cave passages are not
currently accessible.
Based on the 1941 and 1972 Austin Caverns maps, the cave lies about 30 to 40 feet
below the closest buildings within 200 feet north and south of the manhole entrance at
3607 Meredith Street.
3
Figure 2
4
Figure 3.
5
Chronology
The history of Austin Caverns is shrouded in legend. What follows is a collection of the
more verifiable reports arranged in chronological order. As is always the case with the
historical records of caves, there are gaps in the available documentation.
1895: The earliest record that can definitely be attributed to Austin Caverns is a land
deed dated Sept. 6, 1895. In this document, William and Dora Walsh leased the cave and
2 ½ acres surrounding the entrance to Joseph W. Burke and John M. Costley for the
purpose of developing the cave as a sightseeing attraction. Though no description of the
cave is given, the deed does outline the fee to be collected at 50 cents; that’s $13.78 in
2012 dollars (Inflation Calculator 2014), so one surmises the cave was deemed at least
somewhat impressive. Also of note, the deed describes the cave entrance as “almost in a
circle,” suggesting that it was perhaps an excavated sinkhole, as standard quarry cuts
would be angular (Land Deed 1895, Appendix D).
1927: An article in the July 9, 1987, issue of West Austin News reports that Travis
County deed records show that a lease was signed in August 1927 between the owners,
Mr. and Mrs. L. McGinnis, C.R. Hamilton and F.D.Badger “to use, operate, rent and
hold the cave… located on a part of Daniel Gilbert Survey… for any legitimate purpose
connected with the operation of said cave as a pleasure park, sightseeing object or for
any commercial purpose” (Johnson 1987).
1932: Numerous sources say that in 1932 Frank Chote of Houston opened the cave for
tours, complete with electric lights. It is said that at this time a second entrance was
created into the cave and a staircase was installed (The American Statesman. Feb. 7,
1952, p. 13, Blast Sealed Mystery of ‘Lost’ Cavern, Hamilton 1963, Kelly 1978, Johnson
1987, Reddell 1996, Russell 2006).
1941: Carl C. Clayton surveyed and produced a sketch map of Austin Caverns
(Appendix A). The map shows a room in the north portion of the cave where a 30 by 40
foot block had fallen, and possibly formed a similar, smaller adjacent room (15 x 35 feet
diameter). Possibly these were ancient roof collapses, although an Austin Statesman
February 7, 1952 article suggests some blasting inside the cave may occurred before the
1930s (Russell 2006, Texas Speleological Survey 2014).
6
1948: National Speleological Society Bulletin 10, published in April 1948, gives
directions to the cave with instructions that the main cave is north, though it does not
describe the cave in any detail. An article also states “there are at least 12 unexplored
openings within a few hundred yards of the entrance to Austin Caverns.” Also
noteworthy, this publication gives a description of the cave as reported in The Telegraph
and Texas Register on Feb. 5, 1840. This is erroneous and is actually a description of
Bandit Cave. This error, others quoting this error, and the original article are commonly
encountered in the lore of Austin Caverns (Craun 1948, White 1948, Johnson 1987,
Hamilton 1963, Kelly 1978, Johnson 1987, Reddell 1996).
1952: The best description of what the inside of the cave is actually like comes from a
series of four articles documenting “full scale” exploration of the cave conducted by the
University Speleological Society (U.T.Grotto) appearing February 5, 6, 7, and 8, 1952, in
The Austin Statesman (Appendix D).
The second article quotes Carroll Slemaker at length:
“The entrance to the cave is at one end of the quarry, a boarded-over hole
enclosed by barbed wire. Beneath the boards the hole drops 30 feet into the
limestone: at the bottom a large crack leads off to the west, and a small squeezeway drops down and go’s to the east. The westward crack leads to a small
passageway which comes out at the base of a bluff about 150 feet south of the
entrance, but the squeeze-way takes one into a different world. Beyond the tiny
entrance is a 20-foot slope of rock and debris, leading to a place where the tunnel
opens into a wide, low-ceilinged chamber filled with cascading flows and peculiar
pillars frozen in translucent rock. Just past this is an apparent end to the cave.
But, by kneeling down you notice a small corridor leading back under a ledge.
Here you lie down and wiggle snake-like through the passage. Finally the ceiling
rises and the walls recede to disclose another large room. Immediately to the
right, in a small circular chamber, is the largest formation in the cave, a
stalagmite whose bulk almost fills the small room in which it is located. At the
opposite side of the room two small openings permit access to still another room,
on a higher level. At one end the room narrows down to an extremely small size
and leads off unexplored, to the east. Back in the second large room, a trail
wanders farther into the cave/ After following the trail several minutes you
encounter the last of the accessible portions of the cave, a large room in which
huge sheets of rock have fallen or have been jarred loose from the ceiling,
blocking a possible extension of the cave beyond this point.”
7
Slemaker is also reported to have contacted Raymond Shelton, Austin resident who often
helped Chote manage the cave. Shelton was said to have told Slemaker that the cave was
no more extensive in 1932 than it was in 1952 (The Austin Statesman, Feb. 7, 1952, p. 13,
Blast Sealed Mystery Of Lost Cavern, Appendix D).
1951-1954: Predictably, children from nearby growing neighborhoods were attracted to
the cave, attempting to climb down its slippery entrance. Major attempts to seal the cave
to protect public safety involved pouring rocks, tar, and concrete into the cave entrance
and blasting the interior of the cave to “seal” it. Consequently, “this caused a partial
collapse of the roof and generally shifting of the rock. In fact, the whole roof was
weakened and shifted quite frequently in the form of breakdown. Several slabs of rock
were always in evidence hanging just barely supported and ready to fall on the slightest
provocation….one night, the cave was mapped. Exactly one week later, the map was
useless due to recent breakdown” (Hudson 1954). Most of the north passages are
supposedly “sealed,” allegedly by blasting. According to Bob Hudson in 1954, photos of
the cave were taken by cavers from 1951 to 1953, but these photos have not been located
(Hudson 1954, Russell 2006, Russell 2014, Texas Speleological Survey 2014).
1955: USGS topographic maps show two sinkhole depressions in the block containing
Austin Caverns just south of Meredith Drive. See Appendix B.
1959: A child was hurt falling in the entrance, which the City of Austin sealed. A
developer filled the quarried sinkhole and constructed houses over it (Warden 1963,
Russell 2006).
1960-1963: After construction of homes and infrastructure by a private developer, it
became apparent that the area around Meredith Street lies within an internal drainage
(sinkhole) area with no natural surface drainage. Project surveyor and caver Eg Smith
shows the developer where to create a shaft to reach the filled Austin Caverns for the
purpose of runoff drainage. This reportedly consisted of a 25-foot vertical pipe stack with
a 90-degree elbow leading into the southern portion of the cave (Warden 1963).
1963: On June 21, 1963, Tom Warden, Terry Raines, and Eg Smith entered the new
storm sewer drain that led to the south passage. Much of the cave, and perhaps 10 feet at
the storm sewer entrance, had been filled in with rock. Tom Warden was optimistic that
the diversion of stormwater will open up the cave passages (Warden 1963).
8
1964: In August 1964, Bill Russell and Susan Baker make a trip into Austin Caverns
and report that the cave passages are getting smaller, becoming filled with stormwater
debris (Estes 1964).
1970: In December 1970, cave geologist Mike Warton mapped the portion of Austin
Caverns on the south side of Meredith Lane (Appendix A). This map shows an additional
passage near the quarry not mapped on the later 1972 map. While the passage appears to
be the same section mapped in September 1972, the earlier map shows the cave trending
120 feet east to a quarry, rather than south. The Warton 1970 map appears to be
considerably mis-oriented compared to the 1972 map of the same passage based on (1)
the entrance passage does not follow the same general trend as an extension of the
Clayton 1941 map of the north passages, (2) the end of the cave is not anywhere near the
quarry termination within a sinkhole shown on the 1955 US Geological Survey
topographic map, and (3) in 2004 Karst-Tec Consulting measured the entrance passage
trend as 194 degrees, which is nearly south not east (Texas Speleological Survey, 2014).
September 9, 1972: Ron Fieseler, William Russell, Carol Russell, Craig Bittinger, and
John Steele mapped the south extent of Austin Caverns in two hours (Bittinger 1973,
Appendix A). This map shows the passage extending south for about 140 feet to a quarry.
1980~:
Sometime around 1980 the cave became inaccessible (Russell 2006).
Mid. 1990s: In the mid-1990s, erosion at the base of the pipe stack opened portions of
the cave and became problematic. According to a Texas Speleological Survey report:
“After the blockage to the south, much of the water was forced back under the
entrance pipe and down into the main cave to the north. This flow eroded the fill
beneath the concrete pad that supported the vertical pipes, and the entire stack of
pipes was in danger of collapse. By 1997 enough sinkhole fill had been carried
into the main cave that a room about six feet high and ten feet in diameter had
formed beneath the concrete pad that supported the vertical stack of
pipes. According to the 1941 cave map there was only three or four feet of
vertical distance between the bottom of the washout and the main cave
passage. Considerable material had been washed down into the cave. There was
an attempt to dig out the remaining rocks, but digging conditions were gross and
the dig was not completed” (Russell 2006).
9
1993: David Locklear initiated a Texas A&M Grotto project named Restoration of
Austin Caverns and Karst (RACK), excavating sediment onto a rented trailer. David
observed that the ground around the storm sewer standpipe had voids and “appeared to be
on the verge of collapsing.” This effort excavated only a few feet into the south passage.
(Locklear 2014)
1996:
University of Texas cave biologist James Reddell noted:
“Austin Caverns, presumably once one of Austin's environmental gems, serves as
a classic example of the destruction of a valuable natural resource through
neglect and irresponsible urbanization…In recent years trash, leaves, and silt
have blocked entry into the southern passage. As a result water is undermining
the sinkhole fill to the north on which the street is built. Early in 1995 settling of
the fill damaged the street. Rather than deal with the problem correctly the city
simply placed metal sheets over the street. The only long-term solution to the
problem will be to remove more of the fill to allow water to enter the main part of
the cave. Failure to do this will result either in serious collapse of the street or
complete sealing of the cave with resultant flooding of houses built in the
depression in which the cave is located” (Reddell 1996).
1998: A Texas Speleological Survey report describes that by 1998 the fill above the
washout begin to settle. Part of the street collapsed and had to be covered with steel
plates. Eventually the city repaired the street by digging out the old sink and filling back
under the pipe, and in the process sealing off any potential access to the historic main part
of the cave. Some small amount of water still appears to be flowing around the pipe and
reaching the old cave, but for the most part there is no place for the floodwater entering
the pipe to go. The cave to the south toward the old quarry entrance is blocked tightly
with leaves and debris and the openings to the main cave are now filled. (Russell 2006)
2000: City of Austin Watershed Protection hydrogeologist Sylvia Pope conducted two
repeated dye traces in the Austin Caverns area to determine Edwards Aquifer flow paths
and discharge sites. On June 1, 2000, she injected 1.5 pounds of rhodamine WT dye into
the Austin Caverns manhole entrance at 3607 Meredith Street and 0.7 pounds of sodium
fluorescein into a surface depression at 3511 Clearview Drive. The resident of 3511
Clearview Drive reported that their lot was the edge was the edge of the historic
quarry/sinkhole that was filled, although the circular depression mapped on the 1955
USGS topographic map (Figure 2, Appendix B) does not extend that far to the east.
Monitoring was conducted at a spring in Reed Park, in multiple sites along the north bank
of the Colorado River, in Cold Springs, and in a well at the University of Texas
Brackenridge field lab. The traces were repeated on June 16, 2000, using 4 pounds of
10
rhodamine WT at 3607 Meredith Street and 2 pounds of sodium fluorescein at 3511
Clearview Drive. No dye was recovered at any monitoring site, although because of
possible dilution of the dye by eddies in the Colorado River, this lack of detection does
not indicate that the monitored sites were not downgradient of the injection sites.
2004: In 2004 Karst-Tec Consulting was hired to attempt to dig open Austin Caverns
for inspection. Twenty feet of south-trending passages were opened, and 4.5 square yards
of debris were excavated over 5 days. Karst-Tec Consulting evaluated that large unstable
breakdown slabs on the east wall and ceiling of the south passage would make further
excavation “difficult and dangerous.” From their inspection they believed that sediment
derived from recent home construction had washed into the cave and plugged the
passage, causing surface flooding with heavy precipitation events. It was unclear if the
standpipe was set in competent bedrock or fill material, and significant erosion of its base
was observed. One additional day was allocated for attempting to reopen the north
passage and a possible lead was uncovered but not pursued (Thibodaux and Fant 2004).
Lee Jay Graves (2014 personal communication) was a member of the Karst-Tech
excavation team and is a current City of Austin employee. He reports that, in his opinion,
excavation in the south passages did not seem unstable and can be continued as safely as
any excavation he participated in over 40 years. He also reported that drip water that
appeared to be effluent wastewater, based on the smell of the drips, entered the south
passage. The presence of leaking wastewater was unconfirmed.
Discussion
In their natural condition, caves are generally relatively stable compared to man-made
structures, having withstood thousands of years of weathering. Subsurface caves are
generally formed millions of years ago as groundwater flowing toward the Colorado
River dissolved linear cavities at or below the water table. Collapse sinkholes naturally
occur over long periods of time as erosion of the ground surface (denudation) causes
stress fields from an existing open cavity to reach the ground surface (Aley et al. 1972,
Kastning, 1987, Veni, 1994). Otherwise, collapse may occur over long periods of time in
the subsurface, though its effects may not reach the surface where they can be readily
observed. Aside from natural process, some anthropogenic factors are known to enhance
sudden or catastrophic sinkhole collapse including: the lowering of the water table
contributing to loss of buoyant support for subsurface rocks, diversion of water into a
cave or subsurface void leading to enhanced erosion and dissolution, the placement of
heavy structures - such as buildings and water ponds - over pre-existing voids, the
removal of subsurface supporting material - such as through salt removal and mining
(Aley et al. 1972, Newton 1984, Aley et al., 1987, Waltham et al. 2005, Land 2012).
Vattano et al. 2012, describe sinkhole collapse of structures built over a historical quarry
11
in Italy. Factors influencing the collapse of a void include the lateral diameter of the void,
the competency and thickness of overlying bedrock and the presence of fractures, faults
or weathered bedrock and other disconformities that potentially weaken the rock. In
general, the larger the diameter of a void and shallower the overlying rock thickness, the
likelier that the stress fields will reach the surface and be observed. The stability of
Austin Caverns is not calculated in this report, only the presentation of observations and
factors that potentially affect its stability. The estimation or calculation of cave stability is
deferred to a structural and/or geotechnical engineer.
In some parts of the world, catastrophic sinkholes are observed. In Florida (Hyndman and
Hyndman, 2006, p. 232), China (Jiang et al., 2012) and Witwatersrand province of South
Africa, the shallow water table and anthropogenic pumping of groundwater are attributed
as major factors in common sinkhole collapse. Diversion of stormwater runoff
underground was attributed as a cause for roadway collapse in Warren County, Kentucky
(Hyndman and Hyndman, 2006, p. 232). Leaks of water and wastewater lines were
attributed to catastrophic sinkhole collapse in Minnesota (Alexander et al., 2012),
Pennsylvania (Hyndman and Hyndman, 2006, p. 232) and Guatemala (Than, 2010).
Large collapse sinkholes observed in New Mexico (Land, 2012), Louisiana, and New
York (Hyndman and Hyndman, 2006, p. 233) are associated with the removal of salt
strata from the subsurface. In Austin, Texas, collapse sinkholes are common that opened
over the last two million years, while sudden catastrophic sinkholes are very rare
(Hauwert, 2009, p. 67-68). On January 25, 2012, a sinkhole collapsed below a waterquality pond in the Arbor Trails shopping mall in southwest Austin after a heavy rain,
where about ten feet of water filled the pond (Hunt et al., 2012; Wong et al. 2012). For
the year after construction of the mall and prior to the sinkhole collapse, this pond
continually leaked. The lack of catastrophic sinkholes in the Austin area can be attributed
to the competency of the Edwards Aquifer bedrock, relative depth of the water table, and
absence of thick, highly soluble evaporate deposits such as salt and gypsum.
In the case of Austin Caverns, past decisions to develop home sites adjacent to and over
the sinkhole and route stormwater directly into the cave have led to its potential
instability. The original sinkhole and cave entrance was filled with loose rock and soil to
make way for urban development. Stormwater was diverted by the original developers
into the cave, presumably because it was cheaper than routing it to surface drainages.
Because caves are not as efficient as surface drainages in eliminating sediment, leaves
and other debris, stormwater, plugging of the cave passages with debris after heavy rain
events has contributed to surface flooding. Furthermore, in natural large sinkholes it has
been measured that about 80% of infiltration occurs through soils on slopes of the
sinkhole catchment, and the smaller remainder entering the sinkhole drain. (Hauwert and
Sharp 2014). Urbanization increases impervious cover such that most runoff to an urban
sinkhole enters the sinkhole drain with higher erosive capability. The potential instability
12
of the material used to fill the sinkhole could potentially lead to greater incidents of
utility line leaks that can further contribute to generation of subsurface voids as well as
structural collapse of roads and other infrastructure. Blasting of the north passages from
1951 to 1954 could have destabilized the cave further. Note that blasting rock does not
reduce the net open volume, but potentially shifts the void space higher or causes surface
subsidence. A better long-term approach would have been to preserve the land around the
sinkhole and to gate or fence the cave rather than repeatedly attempting to fill and blast
the cave. In 1996, Dr. Woodruff used Austin Caverns to show “there are yet other
environmentally sensitive areas in the city besides Barton Springs. Clearly, given the
development pressure in West Enfield/ Tarrytown and given its situation on a karst
terrain, we may expect a long-term worsening of groundwater conditions and increasing
flood hazards of densely developed areas.” However, the environmental sensitivity of the
cave and potential flooding problems were not generally recognized when the majority of
development occurred in the Austin Caverns area.
While current city code would have avoided these problems, these codes were not in
effect when this neighborhood was built, around 1960. Under current city code, the
sinkhole catchment would be preserved including the area from 150 up to 300 feet from
its sinkhole rim. Infrastructure such as buildings and utility lines would not be placed
over the sinkhole.
It is possible that, if Austin Caverns is restored at considerable public expense, it may
have historical and educational significance. This site could potentially be developed into
a pocket park to serve the neighborhood, with possible opportunities to become a Citywide amenity. If the original sinkhole site were publicly acquired and the unstable fill
removed, Austin Caverns could potentially be utilized in public education about the
Edwards Aquifer. Currently there are limited opportunities for the public to experience
Austin’s unique underground world, with demand far exceeding opportunity. The
Imagine Austin Comprehensive Plan (City of Austin 2012) notes that “Austin has an
active historic preservation program” of sites that are part of Austin’s uniqueness. The
City of Seattle utilizes abandoned underground areas of the city as tourist attractions by
offering historic tours (http://www.undergroundtour.com/about/history.html). Though
Austin Caverns is certainly a historical part of Austin’s uniqueness, preliminary inquiries
to the Texas Historical Commission suggest Austin Caverns may not qualify for
placement on the National Register of Historic Places nor for designation as a State
Archeological Landmark in its current condition (Patricia A. Mercado-Allinger & Tiffany
Osburn, Texas Historical Commission, 2014). Because of the extensive impacts to Austin
Caverns, any attempts at restoration would be challenging and possibly deemed not
practical due to excessive costs.
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Conclusion
Austin Caverns was mapped to extend 30 to 40 feet deep beneath the closest buildings
within 200 feet north and south of the manhole entrance at 3607 Meredith Street. Since
the neighborhood was constructed around 1960, flooding complaints have been reported
that result from home and infrastructure construction within an internal drainage
sinkhole. There are unconfirmed reports of street subsidence and utility line leaks that, if
true, appeared likely as a result of fill subsidence near the cave entrance. The occurrence
of utility line leaks and street subsidence were not investigated and verified for this
report. While many reports of cave instability were reported by cave explorers, no reports
of surface bedrock instability were found. The undesirable situation of Austin Caverns is
largely the result of how natural features were recognized and protected half a century
ago. Primary factors include blasting and filling of the cave and sinkhole entrance,
construction of residences and associated infrastructure over the sinkhole entrance and
cave footprint, and diverting urban stormwater into the cave. Resulting problems include
localized flooding, possible roadway subsidence, and potential degradation of the
Edwards Aquifer water quality. Restoring Austin Caverns to a more natural state and
improving adjacent infrastructure to current city standards likely will never be practical
because of the high cost, but may be further considered for its potential to provide some
benefit to the City, neighborhood and the environment.
Recommendations and Considerations
In order to reduce localized flooding, the potential for further development of subsurface
voids and collapse, as well as to preserve the water quality of the underlying Edwards
Aquifer; the following actions may be considered pending funding:
Water Quality (Short Term Solutions)
1) Divert stormwater away from Austin caverns, or as much as possible.
2) Conduct closed circuit TV inspections of the wastewater, water and stormwater
utility lines north and south of Meredith Street between Raleigh Avenue and
Rockmoor Avenue, as well as at the extension of Stevenson Avenue, to determine
whether leaks are present. If leaks are found, the responsible City department
should be notified of the need for repair.
3) Service calls for utility lines leaks, roadway and other infrastructure repair could
be studied to determine if the 4500 block of Meredith Street (area of Austin
Caverns) has a history of higher frequency line breaks than other areas. This may
indicate whether ground subsidence is occurring. Some areas farther east of
Austin Caverns are underlain by Del Rio Clay and these areas may have their own
characteristic, but unrelated, stability problems, and should not be used for
comparison.
14
4) An attempt should be made to have cave specialists examine the cave from the
bottom of the Meredith Street standpipe, as the cave status has not been evaluated
since the 2004 Karst-Tec Consulting investigation. It is assumed that the cave is
completely plugged with washed in material; however, the true status is unknown.
If the cave is completely plugged with washed-in debris it is no longer able to
function as a drain. Surface drainages in urban areas often require regular
maintenance and removal of debris to allow safe and efficient drainage. If Austin
Caverns is to function as a stormwater drain, regular maintenance to remove
washed-in debris should be expected, though this may not be practical or safe.
Cave Restoration (Possibly Impractical Long Term Solutions)
5) If the cave can be safely excavated from the bottom of the Meredith Street
standpipe, manual excavation of the cave should be considered to allow further
inspection of the cave status for stability, to remove plugging debris that has
washed in, and potentially to restore the cave to more natural conditions. Cave
excavation has been conducted in local caves, as well as Austin Caverns, for 80
years with few injuries and no fatalities when performed by experienced cavers
evaluating the safety of the cave as they progress into it. If the cave is observed to
be too unstable, then the excavation clearly should not begin. Based on available
information, it is not clear whether the cave can be safely excavated. It is quite
possible that excavation to unplug the cave cannot be safely conducted from the
bottom of the Meredith Street standpipe.
6) If continued chronic problems with drainage, leaking utility lines or subsidence
occur that are the result of poor historical design in building over a large cave and
sinkhole(s), it may be more cost effective to buy out the land, assuming there is
available funding, than to continue maintaining structural integrity and
infrastructure in an area that would be buffered according to current code; this
would depend on whether the property owners desire to sell their property.
Essentially property inside an internal drainage basin is functionally within a
floodplain, as a cave system should not be relied upon to eliminate floodwaters. If
the property over the quarry/sinkhole entrance is acquired by the city, excavation
of the fill material may be possible to reveal the sinkhole and underlying cave
entrance.
7) Consideration should be made for restoring the sinkhole and cave and dedicating
it as a historical landmark and educational resource about the Edwards Aquifer.
The resulting pocket park could be a neighborhood gem, and if the cave is safely
developed into an educational attraction then it may be possible that the site could
become a tourist attraction displaying unique features of the Austin area.
15
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City of Austin, 2012, Imagine Austin Comprehensive Plan. [pg 37,40]
Craun V. 10 April 1948. Commercial Caves of Texas. NSS Bulletin 10. pg 33-45.
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Hamilton B. 1 July 1963. Mysterious West Austin Caverns Opened by Housing
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Appendices
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Appendix A. Historical Cave Maps (Texas Speleological Survey)
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Appendix B. Historical Topographic Maps
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Appendix C. Texas Speleological Survey and Other Caver Reports
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1952 Entrance
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July 20, 1968
James Reddell &
Richard Smith
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From Woodruff, C.M. and Sherrod, C.L., editors, Urban Karst: Geologic Excursions in
Travis and Williamson Counties, Texas. Austin Geological Society field trip guidebook
16 pg 5, 6.
Austin Caverns, Travis County, Texas
James R. Reddell
Austin Caverns, presumably once one of Austin's environmental gems, serves as a
classic example of the destruction of a valuable natural resource through neglect and
irresponsible urbanization.
The earliest history of the cave is unknown. An 1840reference in the Telegraph
and Texas Register has been ascribed to the cave. This certainly is in error and the cave
described there probably refers to Bandit Cave in Rollingwood.
It is unknown if Austin Caverns ever had a humanly accessible natural entrance.
The first recorded entrance was in the wall of a quarry. Early references indicate that the
cave was known prior to the quarrying operation but no reliable information hasbeen
found. In 1932,Frank Chote of Houston opened (or enlarged) an entrance in a large
depression about 180 ft. north of the quarry entrance. A stairway and electric lights were
installed and the cave was operated commercially. This venture failed after a few months,
as did several other commercial caves in Texas during these difficult times. The cave was
considered a hazard and at some point the sinkhole entrance was sealed. This entrance,
however, re-opened a few years later.
The cave was mapped in 1941by Carl Clayton. This map shows about 500 ft. of
passage, including several rooms, the largest more than 50 ft. in diameter. The cave
reportedly contained numerous attractive speleothems. In 1948 when the first description
was published most of the speleothems were broken.
Two passages extended from the bottom of the 25 ft. deep entrance. One to the
south extended about 180 ft. to an opening in the quarry wall. The other passage led north
into a series of passages and chambers. The first systematic exploration of the cave for
which there is reliable information was in 1952 by the University of Texas Speleological
Society. At that time they found a large part of the cave blocked by collapse. Additional
collapse occurred in 1953and in 1954the sinkhole entrance was again sealed. About 200
ft. of passage was still accessible from the quarry entrance until about 1959 when the
quarry was filled and houses built on it.
The contemporary history of the cave began in 1963 when plans for development
indicated the need for a storm sewer drain to prevent flooding of the depression in which
the sinkhole entrance had been located. The old sealed entrance was re-opened and storm
waters channeled into it by a drain. Unfortunately only a portion of the fill was removed
and only the small southern section was available for direct entry by water. The first
exploration by cave explorers of the cave revealed only about 30 ft. of passage. Flood
waters entering the cave opened up the passage to the south to the sealed quarry
entrance.
In recent years trash, leaves, and silt have blocked entry into the southern passage.
As a result water is undermining the sinkhole fill to the north on which the street is built.
Early in 1995 settling of the fill damaged the street. Rather thandeal with the problem
correctly the city simply placed metal sheets over the street. The only long-term solution to
the problem will be to remove more of the fill to allow water to enter the main part of the
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cave. Failure to do this will result either in serious collapse of the street or complete sealing
of the cave with resultant flooding of houses built in the depression in which the cave is
located (William H. Russell, personal communication).
In addition to the obvious undesirability of channeling road and yard runoff with its
load of pollutants into the aquifer, any endemic cavernicole fauna has been extirpated from
the system. It is remotely possible that cave-adapted species still exist in the northern part
of the cave. Thisis unlikely because of the intense urbanization above the cave. The high
degree of impervious cover will have reduced water entering the system. In addition, what
water does find its way underground will carry a heavy load of pesticides, herbicides,
fertilizers, and other pollutants. Thisisolated limestone region doubtless contained an entire
community of cavernicoles,many of which were probably limited to this small area and are
almost certainly now extinct. Explorations prior to the most recent blockage of the cave
found an incredibly repulsive passage containing every conceivable kind of trash and
pollutants. The cave teemed with life, but the only species found were forms adapted for
urban life (cockroaches, hot house millipedes, earthworms, pillbugs, etc.).
In summary, a large attractive cave potentially of great biological and geological
interest hasbeen converted into a source of direct pollution of the aquifer. Furthermore a
failure to consider the consequences has already led to damage to the street and the
potential for more serious problems is great.
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Appendix D. Newspaper Articles on Austin Caverns
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