This indicator measures community noise levels in the low-density residential land use areas in the Tahoe Region. Cumulative noise or community noise equivalent level (CNEL) is a noise measurement based on a weighted average of all measured noise over a 24-hour period. Excessive noise in the Tahoe Region can impact wildlife, visitors’ experiences, and residents’ quality of life. Primary drivers of community noise levels in the Region have been attributed to anthropogenic activities such as vehicular travel in transportation corridors and aircraft activity at the South Lake Tahoe Airport. Regional programs such as encouraging the use of low-noise pavement and limiting noise at outdoor concerts aim to reduce community noise levels in the Region. CNEL is monitored in plan areas across the Region annually.
Status
Average CNEL noise levels in low density residential areas.
Data collected by the Tahoe Regional Planning Agency. Access detailed datasets, including Noise Data Summaries, on Tahoe Open Data.
Evaluation Map
Low Density Residential Area Noise Monitoring Locations
N17: Background noise levels shall not exceed the following levels: 50 dBA CNEL (Average Noise Level) in the Low Density Residential Areas Land Use Category.
Key Points
Compared to the 2019 Threshold Evaluation, there is little to no change in overall noise levels in low density residential areas.
Noise levels in each plan area are assessed using the maximum 24-hour noise measurement (i.e., the loudest noise measurement of the day, regardless of duration). Most days most plan areas are within the noise standards, although many plan areas exceed the noise standard on a few days.
The average noise level across all monitored low density residential areas is within the threshold standard.
About the Threshold
This indicator measures 24-hour noise levels in the low-density residential land use areas in the Lake Tahoe Region. Due to the rural nature of the communities and the pristine natural areas in the Lake Tahoe Region, excessive noise levels have the potential to negatively impact community ambiance, recreational experiences, and wildlife behavior. In the past, visitors and residents of the Lake Tahoe Region have expressed concerns about the decline in serenity of their community, and their enjoyment of the outdoors due to excessive noise from sources such as on-highway vehicles, off-highway vehicles, over-snow vehicles, watercraft and aircraft. In addition to existing federal, state, and local noise control regulations, TRPA adopted 24-hour noise threshold standards, or community noise equivalent levels (CNEL), for all land use categories and plan areas of the Region. TRPA and local jurisdictions review proposed public and private projects to determine if the project would result in increases in existing CNEL that would exceed applicable standards (TRPA Code of Ordinances). Projects that would exceed applicable CNEL standards are required to mitigate project-related noise.
Anthropogenic noise levels affecting these land use categories and transportation corridor are primarily generated from vehicles, roadway traffic, aircraft and recreational activity. Other secondary anthropogenic noise influences include noise attributed to construction. Natural events such as thunderstorms and wind influence noise levels as environmental drivers.
TRPA monitors background noise levels in all Plan Areas in the Tahoe Basin to ensure noise levels are not disturbing people and wildlife, and to maintain the unique characteristics of the Basin.
Rationale Details
Status Rationale
At or Somewhat Better Than Target. To measure the current status, the average CNEL for all days measured within Low Density Residential land use areas during the current evaluation period of 2020-2023 was used. The average CNEL during this period is 48 dB, which is 96 percent of the maximum allowable levels. Therefore, the current status is at or somewhat better than target.
Trend Rationale
Little or No Change. To determine trend, the average CNEL for all days measured within low density residential land use areas for each reporting period is assessed. The percent change is -0.0779, therefore, a trend of little to no change was determined.
Confidence Details
Confidence of Status
High. Noise monitoring follows monitoring protocol and has consistent data for several monitoring periods with spatial variation.
Confidence of Trend
Low. R²= 0.076, p-value= 0.55. Coefficient of determination is low suggesting a weak trend relationship.
Overall Confidence
Moderate. If one confidence rating is high and the other is low, the overall confidence rating is moderate.