Sustainable Sites Initiative Pilot Project Documentation, Bat Cave Draw and Visitor Center Rehabilitation, Carlsbad Caverns National Park, New Mexico
_Located within the Chihuahuan Desert of southeastern New Mexico, Carlsbad Caverns National Park includes some of the deepest and most intricately-decorated limestone caves in the United States, and provides sanctuary to a colony of nearly 400,000 Brazilian free-tailed bats. The Park was listed as a World Heritage Site and in 1986, the Carlsbad Caverns Historic District was listed in the National Register of Historic Places.
Recent testing of pools located in the depths of the caverns revealed that contaminants such as motor oil and antifreeze were present, and were entering the caves via stormwater runoff from the nearby parking lots. In addition, the impervious paving was reducing the amount of water naturally infiltrating into the caves from the surface, impacting the biological functions of the caverns.
_In Bat Cave Draw, the parking lot was reconfigured to remove most of the pavement, retaining only a small number of paved accessible parking stalls. Curb and gutter were installed to direct stormwater runoff to filtration areas. Over 47,000 square feet of the previously-paved parking area has been restored with a native Chihuahuan Desert plant community.
Great effort is being made to ensure that all vegetation used for the restoration process is of local genetic stock. The project used native grass seed and plugs grown specifically for this project by the Natural Resources Conservation Service (NRCS), from seed collected within the park. This process, while painstaking, maintains the genetic purity of the vegetation and ensures its suitability for the site. After the native grass seed was harvested, the leftover straw was cut and baled to be used as mulch on the project site. In addition to these efforts, plants were salvaged as part of various projects within the park several years prior to construction and maintained in a nursery within the park just over a mile from the site.
NPS partnered with Sul Ross State University (SRSU) to produce additional native plant materials using seeds and cuttings taken from within the park, providing learning opportunities for both NPS and the students and faculty of SRSU. NPS will work with SRSU to produce a handbook detailing the propagation, salvage, production, and establishment techniques for native Chihuahuan Desert plant materials.
As part of ensuring plants have successfully established before supplemental irrigation is turned off and removed, the site is being monitored for three years to track native plant establishment and survival rates, the management of invasive plant species, and water consumption. Through these efforts, the project’s goal to improve the cave ecology and create robust native plant communities that will flourish and enhance the surrounding park ecosystem has been achieved.
_ Design: National Park Service
Project Manager: Tracy Cudworth, PLA
Revegetation Specialist: Sarah Wynn, PhD
Landscape Architect: Jessica Hendryx Brown, ASLA
SITES documentation: Lisa Benson, PLA, ASLA