RSS FeedsNoise
This noise chapter provides a detailed discussion of existing noise conditions for Napa County. The chapter discusses the federal, state, and local policies that govern environmental noise in Napa County (County), describes the methods used to quantify noise conditions in the County, and identifies noisesensitive land uses and major noise sources, as well as existing noise conditions.
The County’s currently adopted Noise Element (amended on August 1, 1990, and reformatted in December 1996) and the County’s noise ordinance establishes policies and regulations concerning the generation and control of noise that could adversely affect its citizens and noise-sensitive land uses. The County has established guidelines to assist in determining compatibility with surrounding land uses.
General noise practice identifies noise-sensitive land uses as being land uses where noise can adversely affect use of the land. These are often places where people live, sleep, recreate, worship, and study; they are generally considered sensitive to noise because intrusive noises can be disruptive to these activities. Such land uses were identified and mapped in the County. In addition, primary sources of noise were identified in the County. The dominant sources of noise in the County are related to transportation, and include automobile and truck traffic, aircraft, and trains. Stationary sources are also present in the County, and they include construction sites, agricultural activities, and commercial and industrial facilities.
 I-80, SR 12, SR 9, SR 121, SR 128, and Silverado Trail are sources of traffic noise in Napa County. |
Noise levels produced by traffic on state highways and county roads with more than 3,000 vehicles per day were calculated using the FHWA Traffic Noise Prediction Model. Aircraft operations were also assessed, as was train activity, although no active freight rail lines are in operation within the County. Noise from construction, agricultural, commercial, and industrial facilities was also quantified, based on information from short- and long-term noise monitoring locations. The County, in consultation with consulting experts, identified all short- and long-term monitoring locations. The noise metric used is day-night noise level (Ldn) and equivalent sound level (Leq).
Contours for existing noise conditions were mapped based on results from the monitoring study described above, as well as on noise modeling and information from previous studies.
In general, it was determined that there are very few existing noise conflicts within the County. A key indicator of noise conflicts is the number of complaints registered with the County. Data provided by the County sheriff’s department indicate that there were few noise complaints received for the years 2003 and 2004.
