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"Since 1986, dedicated to the conservation and protection of our underground resources."

Mapping Devil’s Sinkhole — The Devil’s Sinkhole near Rocksprings is a cavernous wonder.  Visitors to the sinkhole can only peer into the abyss from a platform near the edge.  Thanks to a crew of geologists and photographers, a 3D virtual map of the cave is in the works, one that will give visitors a unique view of this geologic oddity.

This TPWD produced video featuring the LIDAR Project will air on Texas PBS stations the week of February 10-17, 2008 , and repeats August 10-17, 2008.  Check this list for links to Texas PBS to find the schedule for your local station.  It can also be ordered in DVD Format from TPWD/TV - program #1620.

Devils Sinkhole LIDAR Mapping Project

The Texas Cave Management Association (TCMA) is involved into a cooperative project with the Texas Parks and Wildlife and the Bureau of Economic Geology to create a full 3D reconstruction of the currently accessible major passages of the Devils Sinkhole using non-invasive LIDAR (LIght Detection And Ranging) mapping. This would be one of the first and the most complete subsurface model for any park facility at the federal or state level.

A LIDAR scan of Devil's Sinkhole will be used to:

  • produce a 3D computer model of the cave for use by TPWD for public educational and outreach purposes.

  • calculate the volume of the cave and area of the walls and extract debris cone volumetrics.

  • calculate a more accurate estimate of the bat population.

  • estimate the rate of collapse as well as the stability of the debris cone and provide a very accurate elevation survey of the floor of the cave.

  • provide an accurate datum for measuring the changes in groundwater levels in the cave.

  • prove the concept for the use of lidar in managing other important caves in terms of sediment transport, slope stability, and bat populations along with providing a tool to allow for research in speleogenesis of the cave and pit complex.

The Devil's Sinkhole State Natural Area is the most important tourist attractions in the region thanks to the efforts of TPWD and the staff at the Devils Sinkhole Society (DSS). The dedicated volunteers at the DSS have been conducting public outreach programs over the last several years emphasizing the importance of bats in Central Texas. Public education of the complexity and connectivity of central Texas caves is critical to popular understanding of how both natural and human actions can adversely affect these sensitive environments.

The public can observe the sinkhole from a viewing platform built on the edge of the 145-foot drop to the top of the central talus. Although this view is spectacular, it pales in comparison to the massive conical room that extends below the first restriction. There is currently no way for observers from the viewing platform to fully grasp what lies below, or visualize the magnitude and beauty of this natural Texas treasure without the luxury of entering this impressive natural wonder.

The mapping of the Devil's Sinkhole using LIDAR will be performed by the BEG with assistance from Texas Parks and Wildlife Department and volunteers from the TCMA. The BEG will be responsible for providing and operating the mapping equipment and all data processing. The Texas Parks and Wildlife Department will provide access to the cave and provide over site and assistance while work is being performed on the property. The TCMA will provide volunteer labor in helping to move and secure equipment and personnel into and out of the cave. The TCMA will also provide photo documentation of the mapping process for use by the TBEG and the TPWD in reports and displays.

Jerry Bellian using LIDAR to create 3D map in the upper level of Deep Cave.

The TBEG will provide a LIDAR map of the Devil's Sinkhole along with a software viewer that will allow the data to be manipulated and used for educational and scientific purposes.

TCMA is soliciting donations to pay for the cost of the mapping and data processing. If you are interested in donating to the project, contact one of the project managers below. Caving support on the project will be provided by volunteers. If you would like to volunteer, contact one of the project managers. If you wish to volunteer, please submit a summary of your vertical caving experience. Volunteers will be selected based on their vertical caving experience and their availability. We hope to use many volunteers but we expect an overwhelming response from volunteers.

Thanks for your support,

Geary and Allan


TCMA Project Managers

Geary Schindel

Texas Cave Management Association


Allan Cobb

Texas Cave Management Association

(512) 694-5433

For more information on donating or volunteering.

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P.O. Box 7427
Austin, TX 78713