Watercraft Shoreline Test
This indicator measures the number of single noise-event exceedances caused by motorized watercraft in the shorezone of Lake Tahoe. Single noise event threshold standards are based on the numerical value associated with the maximum measured level in acoustical energy during an event. High noise levels can reduce the public's enjoyment of the natural environment, impact the quality of life for residents, and disturb native wildlife. Single noise event violations in the shorezone can be caused by boats navigating too close to shore within the no-wake zone and loud boat engines outside the no-wake zone. Regional programs such as prohibiting noisy boat engines and enforcing the no-wake zone aim to reduce single noise events in the shorezone of Lake Tahoe.
Status
The average number of documented exceedances per day for motorized watercraft determined by the shoreline test (greater than 75 dBA).
Source: TRPA shorezone monitoring data.
Evaluation Map
Shoreline Noise Monitoring Locations
2019 Evaluation
- Status
- Somewhat Worse Than Target
- Trend
- Little or No Change
- Confidence
- Moderate
Applicable Standard
N4: Watercraft shoreline test, 75 Lmax
Key Points
- The number of noise exceedances on the shoreline has gone up and down with no trends evident since monitoring began.
- The number of noise exceedances is very low compared to the number of boating hours, with most sites recording no noise exceedance(s) during the most recent monitoring in 2019.
- Most noise violations occurred at Rubicon Point and Emerald Point.
- The majority of noise violations appear to come from "go-fast / cigarette" boats, with some violations being caused by boats navigating too close to shore within the no-wake zone.
- In 2019, TRPA increased patrols for the no-wake zone and began sending notices to noisy boats to cease operation on Lake Tahoe.
Delivering and Measuring Success
Local and Regional Plans
Monitoring Programs
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Noise - Shorezone
Noise monitors are put out for two weeks during peak boating season (July 4th to Labor Day). Noise monitors automatically record all single noise events that exceed 75 decibels (dB).