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Shenandoah National Park will conduct an aerial limestone application to reduce the acidity of Meadow Run, a stream near mile 90 on Skyline Drive, between February 2, 2026, and February 28, 2026.
Learn more about this project from our FAQs below.
To ensure public safety, the park will implement intermittent closures along Skyline Drive during the treatment and will close the Rip Rap–Wildcat backcountry area for the entire project period. The backcountry area includes the Rip Rap Trail, the Wildcat Ridge Trail, and the section of the Appalachian Trail between its Skyline Drive crossings just north of Rip Rap Trailhead and south of Wildcat Ridge Trailhead. The section of Appalachian Trail will remain open for day use whenever Skyline Drive is open. Visitors may hear helicopter noise near the project area during daylight hours.
Meadow Run Watershed Restoration FAQs
When the treatment window is known, the park will post information on its website and social media, send a message through its alert system, place signage throughout the park, and distribute notices at entrance stations.
Text SHENALERTS to 888777 to receive text alerts about this project as well as other important safety-related information. You can opt out at any time.
To ensure public safety, the park will implement intermittent closures along Skyline Drive during the treatment and will close the Rip Rap–Wildcat backcountry area for the entire project period. The backcountry area includes the Rip Rap Trail, the Wildcat Ridge Trail, and the section of the Appalachian Trail between its Skyline Drive crossings just north of Rip Rap Trailhead and south of Wildcat Ridge Trailhead. The section of Appalachian Trail will remain open for day use whenever Skyline Drive is open. Visitors may hear helicopter noise near the project area during daylight hours.
Excessive acidity in Meadow Run’s soils and waters prevents healthy ecosystems from thriving, harms brook trout, songbirds, native plants, and forest resilience, diminishes resource conditions and visitor experience, and has led the Virginia Department of Environmental Quality to list Meadow Run as impaired under the Clean Water Act.
Under the Clean Water Act, the National Park Service must develop and implement a remediation plan to address stream conditions, and although acidic emissions and acid rain have declined sharply since the 1990 Clean Air Act Amendments, the watershed’s bedrock geology cannot buffer deposited acid or recover naturally, meaning recovery could take well over a century without intervention.
The contract is fully funded by two legal settlements. It is not funded with taxpayer dollars. The project was developed in response to mandates in a court order to “reduce damage to those resources caused by air pollution suffered by the park” and to spend the settlement money “for the restoration of land, watersheds, vegetation, and forest in Shenandoah National Park using techniques designed to improve ecosystem health and mitigate harmful effects from pollution.”
Shenandoah National Park first collected public comments on the Meadow Run Liming Project in October 2020. The park used this input and scientific research to prepare an Environmental Assessment (EA) under the National Environmental Policy Act. From January 29 through February 28, 2021, the park opened another comment period to gather feedback on the preferred alternative and the potential impacts identified in the EA. On April 28, 2021, the National Park Service Northeast Regional Director approved a Finding of No Significant Impact decision document for the preferred action alternative.
National Park Service contractors will apply locally sourced limestone sand to buffer acidity and restore soil and water chemistry.
Contractors will apply limestone sand by helicopter, avoiding ground disturbance and protecting sensitive habitats while managing all aerial operations in compliance with aviation laws and policies.
Non-motorized transport requires an impractically large number of trips: moving 5,000 tons of limestone sand by hand, with each person carrying about 40 pounds, would take roughly 250,000 individual trips. Using pack animals reduces the number of trips but creates other problems: a mule carrying 150 pounds still requires about 67,000 trips, and repeated use significantly increases trail wear.
After delivery, crews must spread the limestone sand evenly across the treatment area, which extends far beyond the existing trail network, forcing volunteers to traverse steep, rocky, and rugged terrain that poses safety risks for both people and pack animals.
Instream liming treats only the symptoms of acidity, not its underlying cause—acidified soils and groundwater. Although it produces immediate improvements in water quality, such as higher pH and increased acid-neutralizing capacity, its effects last only a few years and require repeated applications, whereas terrestrial liming remains effective for decades to centuries.
Soil and stream pH should begin improving within a year, and over the next few years, the soil chemistry and animal and plant life should show secondary and tertiary effects. The treatment should sustain ecosystem benefits throughout the next century, and once stream pH reaches an acceptable level, the park can petition to remove Meadow Run from Virginia’s list of impaired waters under the Clean Water Act.
The park scheduled the treatment for winter for two main reasons. First, the landscape remains mostly dormant at this time of year, which reduces impacts on vegetation and wildlife. Deciduous plants lose their leaves and become less susceptible to leaf damage from falling limestone, and animals are less active. Second, winter brings the park’s lowest visitation, which helps limit impacts on visitors.
The limestone dispersal is not expected to impact air quality. The material is released from a spreader about50 feetabove the treetops, and it consists mostly of large particles that fall quickly to the ground, providing a gradual, time-release effect on the landscape. This process is different from the application of agricultural limestone, which uses a fine powder that can easily drift in the wind.
In addition, on the windiest days—when even larger particles might be more prone to staying airborne—the contractor will not conduct dispersal, either because weather conditions make operations unsafe or because they cannot maintain the required level of control over the application.
During winter, many wildlife species remain dormant or migrate from the park. Research indicates few if any species experience negative impacts. The sand stays airborne only briefly and generally poses no harm on the ground, though helicopter activity may cause short-term disturbance to resident wildlife.
Similar treatments in other areas in the eastern United States and Europe show soil and stream pH should begin improving within a year, and the ecosystem should continue to benefit over the next century. Once stream pH rises above 6.0, the park can remove Meadow Run from Virginia’s list of impaired waters under the Clean Water Act.
