Exploring Spatial Patterns of Overflights at Mount Rushmore National Memorial, Updated 2023–2024

Betchkal DH , Olstad T , Peterson BA , Hutchinson JS , Beeco JA . 2025. Exploring Spatial Patterns of Overflights at Mount Rushmore National Memorial, Updated 2023–2024. Science Report. NPS/SR—2025/330. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2314177

The purpose of this analysis is to monitor changes in the spatial patterns of overflights at Mount Rushmore National Memorial (MORU) after the implementation of the park’s Air Tour Management Plan (ATMP). Overflights were compared across 2023 and 2024 using Automatic Dependent Surveillance–Broadcast (ADS-B) data collected over identical timeframes, May 15th to June 25th. This report expands upon an initial 2022 study that revealed a ring-like spatial pattern of overflights near MORU below 1600 feet mean sea level (MSL; Peterson et al., 2022). Data processing followed standardized protocols using the NPS ADS-B Toolbox (Hutchinson and Peterson, 2024), consistent with other recent analyses (Peterson et al., 2024a; Peterson et al., 2024b; Olstad et al., 2024; Gurung et al., 2024; Peterson et al., 2025; Olstad et al., 2025; Gurung et al., 2025). New effectiveness monitoring methods (Reynolds et al., 2016) were applied within a 330 km² rectangular study area encompassing the local air transportation network. Waypoint- and raster-based techniques were used to detect changes in overflight density and distance from boundaries. Results indicate a substantial reconfiguration of overflight patterns consistent with ATMP implementation. The ATMP is estimated to have produced a sound level benefit of ΔLeq,1s[12.5–20,000 Hz] = –2.8 dB, equivalent to a 50% reduction in acoustic energy exposure and an equivalent doubling of acoustic active space during noise events. These findings suggest that the new, self-organized overflight patterns around MORU achieved an operational fit that improves the acoustic environment and protects park resources and values. This outcome demonstrates that airspace adaptations to minimize noise impacts are not only feasible but can yield durable spatial configurations that meaningfully balance access and resource protection.

Type
Published Report
Authors
Betchkal, Davyd; Olstad, Tyra; Peterson, Brian; Hutchinson, J. M.; Beeco, J.
Date of Issue
2025-07
Publisher
National Park Service
DOI
10.36967/2314177
Units
MORU , NRSS , NSNSD
Keywords
ADS-B, air tours, aircraft tracking, overflights, spatial analysis
License
Creative Commons Zero v1.0 Universal

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