Two-Star Certified Pilot Project
Location: Carlsbad Caverns National Park, New Mexico
Project Size: 14.8 acres
Project Type: Open space - Park
Site Context: Rural
Former Land Use: Greyfield
Terrestrial Biome: Desert
photo by NPS Photo
Contaminants from parking lot runoff at the Bat Cave Draw and Visitor Center, such as motor oil and antifreeze, were being found in cavern pools. The project removed the existing parking area adversely impacting the cavern and rehabilitated it to a natural state using vegetation native to Carlsbad Caverns National Park. Additional work was done to collect and treat runoff in new parking areas to protect the cave and to revegetate areas adjacent to the visitor center and the park's entrance road.
Carlsbad Caverns National Park is located in the Guadalupe Mountains, a mountain range that runs from west Texas into southeastern New Mexico. Elevations within the park rise from 3,595 feet (1,095 meters) in the lowlands to 6,520 feet (1,987 meters) at the top of the escarpment. Though there are scattered woodlands in the higher elevations, the park is primarily a variety of grassland and desert shrubland habitats. The Chihuahuan Desert is the largest and wettest of the North American deserts. Most of this desert is in Mexico, but the park is one of the few places where it is preserved and protected. The park averages more than 14.4 in (36.6 cm) of annual precipitation and has a semiarid, continental climate with mild winters, warm summers, and summer rains. The mean annual temperature is 63ºF (19ºC). Underlying the rugged desert landscape is one of the most important geologic resources in the United States. The Guadalupe Mountains are the uplifted portion of an ancient reef that thrived along the edge of an inland sea more than 250 million years ago during Permian time.
SITES Features + Practices
Notable sustainable features on the project include 100% of plant materials from local genetic stock, no supplemental irrigation once plant materials are established, the use of salvaged materials and plants, and the use of local materials. In addition, the preservation of a historic structure within the site and the elimination of pollution sources are also notable sustainable contributions.
The great diversity of plant materials in Carlsbad Caverns National Park is not widely available in the commercial plant industry and the site conditions in this semiarid National Park are harsh. These situations supported the National Park Service policy to use local genetic stock wherever possible. In this case, using local genetic stock ensured that the plant materials would be best-adapted to the harsh site conditions and that rare or commercially-unavailable plant material would be available for revegetation efforts on this site.
The project team then created a handbook on propagating and establishing Chihuahuan Desert plants for revegetation and restoration purposes. This project was one of several parks around the country used as a model for developing monitoring standards for revegetation in the National Park Service. Seed and plant materials were collected from within the park from local genetic stock or from salvaged plant material where possible.
The massive collaboration from a multidisciplinary team during the project inception proved to be very successful and allowed for a more comprehensive and thoughtful project. Other successful strategies for achieving SITES credits were to make the best use of local materials by using rock, soil, and plant material that were salvaged during the construction process, and importing materials from as near to the site as possible. A temporary high efficiency drip irrigation system is being used to irrigate plants until they are successfully established, and the irrigation system uses solar-powered irrigation controllers.
The NEPA process required an Environmental Assessment be written as well as compliance with Section 106 and SHPO concurrence with the work being performed in and around historic structures. All of the NEPA and SHPO requirements influenced the project's successful outcome, and as more people became involved in the efforts to comply with the requirements, more thought was put into the planning stages.
The integrated design team worked together throughout the comprehensive NEPA process as well as developing a five year strategy to develop plant material and plan for project inception. Regular team meetings were held throughout the design process and during construction to ensure that project goals were continually in focus and on-track for being implemented. Constant cross-division communication occurred. Consistent, thorough communication resulted in a project that met its over-arching goals and objectives.
Maintenance + Stewardship
It is inherently ingrained in the National Park Service mission "To Preserve and Protect...the valuable resources we have inherited for future generations..."
The goals and implementation procedures outlined in the Site Maintenance Plan reflect current practices for maintenance personnel in Carlsbad Caverns National Park, and the practices that will be carried over to the Bat Cave Draw and Visitor Center Rehabilitation. The National Park Service has existing procedures and policies in place for educating maintenance personnel, and for reviewing, updating, and revising maintenance goals and procedures.
To ensure that the project goals are maintained, the National Park Service is currently in the process of writing a contract to assist in an additional two-years of site maintenance because of an identified weed issue.
The most significant site challenges were the native clay soils, the drying winds, and the recent pattern of drought in the region. The location is also very remote, which required strategic planning to optimize construction efforts.
Project Goals + Successes
The primary goal of the project was to remove the source of contaminants that were seeping into the cave pools below the park and to replace them with native vegetation characteristic of the Chihuahuan desert ecosystem. It was important to create a landscape that blended with the natural surroundings in this isolated National Park, and that could survive without supplemental irrigation once the plant materials were established.
Revegetation efforts using plant materials from 100% local genetic stock have been extremely successful. The project revegetated the entire greyfield site, reduced the amount of paving over the caverns, and controlled the stormwater runoff by directing it to oil and grit separators. The project also maintained the integrity of the existing historic stone walls on site, made use of salvaged materials and plants, and used regional materials.
The National Park Service strives to exceed in sustainable practices and this project showcased many of the ways NPS perform those practices outside in the landscape. Motivation to pursue SITES certification did not directly influence the project details, since most of these were completed prior to acceptance into the pilot program. There was, however, a tremendous amount of effort put into the documentation of previous efforts.
There has been a tremendous amount of knowledge gained from the experience of this project that can be applied to other National Park Service projects. For example, the multi-year collaborative effort proved to be a very successful approach.
Acquiring clean topsoil was particularly challenging and despite efforts made by those involved, the topsoil specifications written needed to be more specific. Weed seed brought in by a source, like topsoil, can cost a project a significant amount of money in later years. This has become a valuable lesson on this project.
Carlsbad Caverns National Park
John Benjamin, Superintendent
Danielle Foster, Biologist
Renee West, Supervisory Biologist
Meredith Gosejohan, Biological Science Technician
Shelly Tucker, Biological Science Technician
National Park Service, Denver Service Center
Jessica Brown PLA, ASLA, Landscape Architect/Horticulturist
Sarah L. Wynn, Ph.D., PM, Revegetation Technical Specialist
Tracy Cudworth, PLA, PM, Landscape Architect/Project Manager
Landmark Design, Inc
Lisa Benson, Professional Landscape Architect
Derek Wilson, Architect
Bryan Close, Professional Engineer