Noise, by definition, is “unwanted sound,” and is a subjective reaction to acoustical energy or sound levels. Due to the rural nature of the communities and the pristine natural areas in the Lake Tahoe Basin, sound levels that would go unnoticed in a highly urban or industrial environment outside the basin are likely to be considered noise, and have the potential to negatively impact human health, community ambiance, recreational experience, and wildlife (Francis and Barber 2013; Ware et al. 2015; Laurance 2015).
Based on data from previous research, primary drivers of noise levels in the basin have been attributed to anthropogenic activities and actions. Specifically, vehicular travel in transportation corridors and aircraft activity at the South Lake Tahoe Airport have been identified as the predominant noise sources in the basin. In an effort to address noise impacts to both wildlife and visitors, TRPA Resolution 82-11 established threshold standards for noise, characterized as numerical standards.
Table 10-1 summarizes the assessment criteria for current noise level conditions and trends relative to adopted threshold standards for the basin. The evaluation analyzes two indicator reporting categories for noise: single noise events generated by aircraft and motorized watercraft and cumulative noise events. The threshold standards for each indicator are based on numerical standards using the A-weighted decibel (dBA) as the unit of measure. A-weighting is commonly used for the measurement of environmental and industrial noise, and for assessing potential hearing damage and other noise-related health effects. One adopted policy statement directing the TRPA Governing Board to adopt noise standards for transportation corridors was also evaluated, and was determined to be implemented and in attainment with the threshold standard.