Cave and Karst Management
The following section addresses cave permits, visitor use monitoring, and cave protection, maintenance, restoration, and research. Other guidance can be found in exhibits at the end of this section. Exhibit 1 is a list of considerations for developing cave management strategies within a general management plan. Exhibit 2 presents cave inventory procedures. The guidelines in these exhibits can be adapted to fit individual park needs.
The inventory and classification process should include all criteria for determining cave significance as noted in the FCRPA: cultural, biological (microbiological), geological/mineralogical/paleontological, hydrological, recreational, scientific, and educational attributes. (See Exhibit 5, Significant Caves Criteria.)
Many parks contain high numbers of caves, sometimes exceeding 300-400. For resource protection and visitor safety, many caves may remain closed to regular or general entry. It is expected that programs will be implemented that will allow entry into and the use of some, if not all, of a park’s caves. If a park does allow entry into undeveloped caves or off-trail areas of developed caves for recreation, research, interpretation, or other reasons, such entry should be regulated by a cave entry permit program.
Individual parks have different policies on issuing cave entry permits; however, protection and conservation of the resource(s) and safety for the visitor should be the primary determining factors. In a developed cave, trips off of the established visitor trails should require a written permit, approved by the superintendent or a designee. Anyone failing to comply with park policies regarding conservation of cave resources and/or safety guidelines for cave entry should be denied a cave permit. Any incident should be documented and the chief ranger notified as soon as possible.
There are basically four management strategies for cave entry permit programs.
- Require an entry permit only for those caves with high resource values, fragile or unique features, cultural remains, sensitive ecosystems, or scenic values.
- Require an entry permit for caves with conditions that increase the possibility of injury or illness, such as airborne diseases or high CO2 levels, structural instability, technical difficulty, flooding, or contaminated water.
- Require an entry permit for all caves. The advantage of this approach is that management has very good visitor use records and much more control over cave use. This strategy requires a large commitment of time, money and manpower, if there are many caves in the park, or if there is a significant nearby population center, and the installation of gates or traffic monitoring equipment to maintain tight physical control.
- Require an entry permit for only a certain number of caves for recreational use, based on recreational appeal and the lowest possible risk to cave resources and visitor safety.
Management strategies should be determined through resource evaluations and inventories to determine the method best suited for a given cave. Key information for this determination includes cave inventory records, consultations with those people who are most familiar with the cave, and firsthand knowledge of the cave.
A permitting system must be able to change with changes in cave conditions and patterns of use, or as new information becomes available. Such changes will require reevaluation and possible adjustments to the management prescription. (See Exhibit 3 for a list of health and safety concerns. Exhibit 4 is a list of recommended caving equipment).
Experience has demonstrated that special stipulations to protect cave resources may be necessary in any permit program. Among resources needing special mention are bats, the microbiology of a cave, and both speleothems and speleogens.
Bats should not be handled more than is absolutely necessary for needed research. Only qualified researchers who understand NPS policies and mandates regarding protection of natural resources should do such handling. Humans should avoid interaction with maternity colonies and hibernating colonies. Managers should carefully consider research requests to avoid stressing the bats.
Many recent discoveries have been made concerning microbiological life within caves. Persons traveling in caves should pay special attention to preventing the disturbance of such ecological systems. This can be accomplished by adhering to minimum impact techniques. This should include packing out all trash, catching food crumbs when eating, and carrying feces and urine out of the cave. More common microbes can rapidly displace those adapted to low-nutrient environments if nutrient availability increases. Hair, skin, and surface microbes shed by human visitors have the potential to disrupt these environments for extended periods. Cave passages being studied by microbiologists may require access restrictions. Water should be especially safeguarded. Studies have shown some of the most significant damage in caves occurs in pools where a change in water quality affects microbial communities.
Caves and the features within them are non-renewable resources and all impacts are cumulative. Some caves are more fragile than others are, yet anyone entering a cave should be aware of the potential for damage that can be created from traveling though fragile areas.
The impact of various types and intensities of use should be carefully and systematically documented.
Measuring visitor use
Use at a developed cave may be determined by mechanically or optically counting people on the elevators, as they exit the cave, by ticket sales, or by a ranger. The cave permit provides use data for undeveloped caves. Many of the caves whose use is regulated are not gated; therefore, the accuracy of use data generated from approved permits is dependent largely on voluntary compliance with entry procedures.
Register placement in caves can be a valuable tool for the resource manager, whether or not a permit is needed to enter the cave. Electronic counters should also be considered for some situations. It is important to have a notice on the register, indicating that signing it will not insure a rescue, should the need arise. Valuable information that is needed on a register should include name, address, date, group affiliation, and comments. The register serves as verification of visit by the permitted party, verification of visits by unauthorized parties, verification of visits to certain areas of the cave, baseline information for visitor impact studies, a record of visitor observations concerning vandalism, gate condition, biota etc., and a means of relaying valuable observations, especially in caves that can be entered without a permit.
Measuring impacts to cave resources
Quantitative and qualitative measurement of cave resources is generally more difficult than measuring visitation. Within a park, monitoring of cave vistas and water quality provides principal indices of cave use impacts. In developed caves, cave microclimate may also be monitored.
Vistas are measured using a system of fixed photopoints and videopoints established at selected sites within the cave. Each site is marked with an unobtrusive identification tag mark. These photos and videos provide comparative qualitative and quantitative data for any visible resources.
Aquatic systems are vulnerable to alteration by people and include indices of change that are relatively easy to measure. Common ions, turbidity, bacterial contents, and other parameters that are likely to be altered by human activity should be monitored periodically where feasible to quantitatively measure any change within the cave.
Establishing appropriate visitation levels
The amount of annual use is established from the correlation of three important types of information: (1) established levels of maximum allowable impact, (2) recorded cave use, and (3) the measured condition of the resource associated with various levels of use. The methods used to evaluate impact must be accurately measurable with a consistent technique, and resource condition must be correlated with the presence of people in the cave.
A maximum level of acceptable cumulative impact should be established, and visitation regulated according to the desired "life" of the route. In many cases, a fixed trail--which by definition is allowed to accept an infinite amount of impact--and well-managed off-trail policies can reduce impact of the surrounding resources to nearly zero. Furthermore, timely mitigation efforts can keep the impacts from ever exceeding the maximum level, allowing visitation to continue indefinitely. However, the impact from visitation should never exceed the park’s ability to keep it below the pre-established limits.
Need for Inventory and Monitoring
Use of caves by humans can have significant detrimental impacts upon cave resources without proper management. Biological resources that are being threatened include but are not limited to several species of endangered bats, ferns and lichens, and microbial communities. Especially vulnerable are cave-adapted invertebrates. So little is known about many of these species that evaluation of population stability, impacts from current and past human activities, and probabilities for species survival cannot be assessed without further inventory and monitoring efforts.
Water Quality and Quantity
Because cave and karst systems are intimately tied to local and regional hydrological systems, threats to these natural systems, if allowed to go unmitigated, can have impacts on water supplies and water quality and consequently cave biota, mineral deposits, and speleothems. Direct threats to cave and karst groundwater aquifers can include interruption or diversion of natural hydrologic flow; land disturbances; runoff from roads, parking lots, lawns, and roofs; inappropriately placed toxic waste repositories; pollution/runoff from sewage and septic systems livestock and poultry operations, and/or landfills; leaks from improperly maintained and monitored underground gasoline storage tanks; oil and gas leaks from hydro-carbon development; toxic and corrosive chemical spills; and improper use of pesticides, herbicides, and fertilizers. Any of these situations can cost millions of dollars to remediate and have devastating impacts on karstic aquifers. The hydrologic nature of karst systems allows for easy infiltration and rapid transport of contaminants over large distances below the surface. Regional, rather than localized, aquifer contamination is one of the prevailing risk factors that distinguishes karstic aquifers from porous and permeable aquifers. In addition, erosion as a result of agricultural activities such as excessive tillage and overgrazing, as well as deforestation and fires, can result in significant deterioration of water quality from sediment loading.
Preferred means of cave protection are confidentiality of cave locations, ranger patrols, and use of interpretive media to help people appreciate caves and understand the fragility of cave resources. Interpretation is an extremely important management tool since it encourages voluntary compliance and cooperation in protecting these nonrenewable resources.
Gates are an obtrusion on the aesthetic integrity of the cave entrance and are often deleterious to the ecology of a natural cave, especially if improperly designed. Poor gate designs may impede or obstruct airflow and the movement of bats and other organisms into and out of the cave. Even a "bat-friendly" gate is not as friendly as an ungated entrance, though it may offer protection from external threats. The use of gates to prohibit unauthorized entry is often unsuccessful against determined vandals. This technique should be used to protect park caves only where the need is considered essential and a biologically neutral gate can be constructed. The entrance to many caves is so large that gates are not feasible. Interior gates may be used to restrict access to areas of significant hazards or areas that merit special resource protection. Before a gate is constructed the appropriate specialists should be consulted to ensure mitigation of all park concerns, including ecological, physical, cultural, aesthetic, and law enforcement issues.
Active exploration results in the discovery of the resource, usually in its most pristine condition. Consequently, exploration activities should not be taken lightly or treated as only a recreational activity. Exploration should be management driven and undertaken in close consultation with knowledgeable resource management staff. Participating staff and volunteers must be adequately trained and must demonstrate trustworthiness. Exploration should be allowed only on a "survey as you go" basis. Implementing such a program should substantially reduce the need for unnecessary and potentially damaging trips into a cave or cave passage to gather cartographic data that should have been collected during the initial exploratory trips. Original survey notes should be considered the property of the park, which must provide adequate storage and protection of the data. Survey data can be sensitive, and, if so, may not be made available to a FOIA request pursuant to the FCRPA provisions mentioned above. Survey data should not be distributed without careful consideration of the potential for misuse that could adversely impact the cave, including portions of the cave yet to be discovered.
During cave exploration an area may require enlargement to permit entry into virgin passageways or chambers. Permission to enlarge a constriction or to dig through breakdown or cave fill must be obtained in writing from the park superintendent or a designee. Environmental alterations and potential damage to cave resources should be given the highest priority consideration. The alteration must have a strong justification and permission can only be granted upon demonstration that all impacts can and will be mitigated. Explosive charges or mechanical devices, such as "rock splitters" or jackhammers, should not be permitted for use in park caves except for pre-approved construction uses within the developed caves.
Exploration should include but not be limited to the following.
- Cartographic surveys of all known caves within +/- 2% error of closure will be conducted. Data should be delivered on computer disk, compatible with a geographic information system (GIS), and as finished plan and profile Class 1 maps. Entrance locations will be recorded on aerial photographs of each park and on U. S. Geological Survey (USGS) topographic maps; universal transverse mercators (UTMs) will be required for each cave entrance marked on the maps. In parks with numerous caves, brass survey markers at least one inch in diameter may be used for marking cave entrances and to tie into surface and cave surveys.
- Baseline resource inventories will be conducted in conjunction with cartographic surveys. Initial data collection will include the following information: geology, mineralogy, archeology, paleontology, hydrology, and biology (flora and fauna).
- Researchers, park personnel, and skilled volunteers through agreements will accomplish the data collection process. Information from a successful exploration program is fundamental to effective management of NPS cave and karst resources. The consequences of not implementing this program include non-compliance with federal law and NPS policies, degradation of cave resources, and increased potential to allow karstic aquifer pollution.
Cave Restoration Programs
Any visitation in caves causes some direct degradation of cave resources. In developed caves, foreign materials resulting from human use, such as lint, algae, and fungi, are a problem. To help maintain a natural cave environment, these materials must be routinely removed. Trips into off-trail areas and into undeveloped caves often result in mud buildup on flowstone areas. Such use should be avoided and both developed and undeveloped areas should be monitored and cleaned periodically. Restoration activities should be carefully and properly planned, to avoid doing more harm than good.
Other cave restoration activities are of a non-routine nature, such as restoring scars from construction projects. Old trail fills and areas damaged by development can be partially restored by careful work and research. Care must be taken in establishing trails through any cave. Speleothem breakage is very difficult to restore. Restoration should be conducted whenever possible, with the understanding that damage represents a measurable resource loss. Such efforts may require consultation with other authorities, groups, or entities. Cave restoration should be done with the minimum effort to accomplish the task to reduce impact associated with the restoration activity.
Chemicals used for cave restoration must be used in a manner that will result in no injury to people or the cave ecosystem. Cave restoration work in both developed and undeveloped caves should be scheduled and supervised by qualified resource management staff, and should not be undertaken by untrained persons; knowledge of caves is of the utmost importance. Restoration projects requiring specialized knowledge or skills not available in the park staff should be performed by experienced persons on a contract basis.
Direct and indirect effects of all restoration techniques should be carefully monitored and documented with before-and-after photography to help ensure protection of the cave environment. A cave restoration log should be maintained to document both the details of restoration activities and the results of restoration impact monitoring. Individuals or groups involved in cave restoration work are responsible for the removal of all evidence of their activities (e.g., footprints, tools) from work areas.
Research and other Scientific Activity Guidelines
Considerable cave research and other scientific activities are conducted within parks. Although the NPS occasionally funds studies to aid in the resolution of cave management problems, individuals interested in increasing scientific knowledge of cave and karst systems contribute the majority of cave research. Any competent researcher with a proposed project that is consistent with NPS policies should be encouraged to work in the park. All major research projects and other scientific activities must be adequately peer-reviewed and approved by the superintendent, in consultation with the chief of resource management, using the NPS research and collecting permit (see chapter 5 of this reference manual). Research that may have commercial applications must be governed by special agreements. The park must retain collected data, or copies of data, depending on the terms of the research and collecting permit, and any specimens removed from the cave must be handled in accordance with NPS curatorial guidelines. Because of the non-renewable nature of caves, consumptive sampling, especially of speleothems, must be strictly limited to the minimum necessary for meeting the objectives of the approved research or other scientific activity.
Development should be kept to a minimum, and none should be undertaken that would significantly impact the rest of the cave or karst system. A workable plan to mitigate impacts must be written and peer-reviewed before any development begins, as this kind of activity will result in irreversible impacts. Lawsuits can result without adequate attention to visitor and employee safety.
In planning development of a cave, observe the following points:
- All planning for developments that are major federal actions that could significantly impact the quality of the environment must be done through NEPA.
- Any planning must give ample justification for the need for development of any resource.
- The plans must be developed around a carrying-capacity study (e.g., VERP, LAN).
- The cave must be chosen carefully before it is developed. Resources in some developed caves cannot be protected no matter what resource management techniques are used.
- Baseline data on infiltration rates, cave life, cave climate (especially humidity and carbon dioxide content), and ephemeral minerals (e.g., mirabalite) should be established over at least a year’s period before any changes are made. An integrated team must survey the cave under consideration for development. At a minimum, the team should include a professional archeologist, biologist, paleontologist, and karst hydrologist. It may be necessary to add additional team members in other disciplines depending upon the particular cave resources.
- Development activities should be planned before any changes are made in the cave. It is impossible to protect some resources if mistakes are made in initial development. Initial mistakes multiply expense and damage.
- Development above the cave or within its watershed (which may be different from surface drainage) must be restricted in order to protect the cave. Concentrated hydrocarbon-rich or nutrient-rich discharges from buildings, parking lots, buried gas or sewer lines, and septic tanks, etc. can cause irreversible changes in caves and/or surface collapse, as can changes in natural drainage patterns. Drainage patterns should not be changed. (See NPS Management Policies).
When planning construction, incorporate the following directives:
- Don’t use environmentally toxic construction material. Avoid importing construction material except where absolutely needed.
- Construct trails so that they will not approach delicate formations too closely. Raised trails reduce off-trail damage, reduce construction damage, and permit free flow of water along natural channels. Provide trail curbs to reduce distribution of lint and to facilitate periodic cleaning.
- Place the electrical system along the trail system and minimize wiring across the cave. Don’t bury wire in flowstone and speleothems; replacement would be destructive. Use loose cave material derived from trail construction to hide wires, but do not cement the wires permanently in place. Camouflage wire coverage; i.e., do not use rows of rocks. Concrete-soaked non-organic cloth used to hide wires can later be easily removed.
- Install stainless steel railings (preferable to aluminum) with at least three horizontal bars and at least 1 meter (3 feet) high. Low rock walls are easy to trip over unless used in conjunction with handrails.
- Install a proper drainage system for the trail to adequately catch, remove, and/or filter water from trail cleaning. Do not use cave water for cleaning or monitoring (e.g., filling evaporation pans); outside water can be used if it is chemically compatible.
- Install non-colored, full-spectrum fluorescent or quartz-halogen lights of sufficient intensity to see safely, but not enough to cause extensive algal growth. If lights other than fluorescent are used, measure intensity to ensure they are not promoting the growth of algae. The lighting system should allow lights to be shut off in sections of the cave where visitors and staff are not present. Full strength bleach effectively kills algae, but use at a minimum and never allow it to run into pools.
- Build gates that will permit both animals and air to freely exit and enter the cave and that are compatible with natural and/or historic conditions. Weld on casehardened material to inhibit hacksaw use.
- Disturb cave sediments as little as possible; they are a valuable resource.
With the exception of park concession facilities and contracted work, the maintenance division is usually responsible for the upkeep of all underground facilities. This includes the necessary cleaning, repair, and renovation of cave trails, electrical systems, lights, elevators, restrooms, and the sewage collection and evacuation systems. The maintenance staff should work closely with resource management staff to establish acceptable procedures.
The maintenance division is responsible for assuring that the techniques used do not degrade the cave beyond the trails or other cave developments. Routine maintenance functions, such as changing lights, electrical wiring, and trash collection may require stepping off designated trails. In these instances every effort should be made to obliterate any footprints on the cave floor, using methods decided on during prior consultation with resource management staff. The bottom of footwear should be cleaned before stepping back onto any paved trail. Visible footprints on or off the trail could encourage visitors to leave the trail and damage delicate cave areas.
During maintenance projects in the cave, tools and materials left in work areas for extended periods while not in actual use should be concealed from public view. Foreign substances that will wash or roll off developed areas and enter natural cave areas should not be used. Cave trails may be periodically washed to remove silt and foreign material buildups using techniques developed in consultation with resource management staff. Washings will be collected from the trail surface and removed from the cave. Artificial speleothems should not be created for the purpose of concealing lights or other objects. However, such foreign objects should be concealed using natural features to the extent feasible, as long as the cave is not significantly altered by such action. Chemical-containing products used by maintenance and concession personnel should be approved by the cave resource manager before use in order to investigate the potential for causing damage to cave resources.
Many of the facilities within the cave, especially lights and electrical wires, are located in areas where maintenance access requires special skills (e.g., rope work). If possible, these facilities should be located close to the trail and not require special skills to access. Although the maintenance division may use available expertise in other divisions to provide such skills, the maintenance division should train personnel who can safely use vertical equipment and move about the cave without damaging the resources. It will often be appropriate for the cave resource management staff to provide the necessary training. Having such expertise available within the maintenance division may be particularly important during an emergency.
The use of internal combustion engines in the cavern environment should not be permitted. Such use is detrimental to the cave ecosystem, and a hazard to employee health.Cave and Karst Management Table of Contents | RM#77 Table of Contents