Noise Element Table of Contents

LIST OF FIGURES

1.0 INTRODUCTION

1.1 PURPOSE

The Noise Element is intended to provide ways to reduce existing and future noise conflicts. It includes policies and measures to achieve noise compatibility between land uses.

In accordance with State Law and guidelines, the Element identifies noise sources and areas containing noise sensitive land uses. It quantifies noise levels using noise exposure contours for current and projected conditions within the county. Levels are measured as Community Noise Equivalent Level (CNEL) or the Day-Night Average Level (Ldn), which are measurements of total noise exposure at a given location for an average day. This noise exposure information serves as a basis for achieving land use compatibility within each community and provides baseline levels and noise source identification for use in a noise control ordinance.

1.2 RELATIONSHIP TO OTHER ELEMENTS

The Noise Element is closely related to the Land Use, Circulation and Transit, and Air Transportation Elements of the general plan. The Land Use Element attempts to avoid noise incompatible land uses. The Circulation and Transit Element is linked to this element in that traffic patterns affect community noise exposure. The Air Transportation Element addresses air transportation services in the county and assesses airport noise exposure and land use compatibility criteria. The part of the Air Transportation Element addressing noise from aircraft and airport operations is incorporated by reference as part of the Noise Element.

1.3 SCOPE AND ORGANIZATION

The Noise Element is organized into three major sections: 1) An overview of noise effects, sources, methods of analysis and the existing and projected noise environment, 2) noise control issues and policies, and 3) an implementation program.

The following noise sources are considered:

1. Highway and freeways
2. Primary arterials and major local streets
3. Railroad operations
4. Aircraft and airport operations
5. Local industrial facilities
6. Recreational, entertainment and special events
7. Other stationary sources

Noise-sensitive areas include the following land uses:

1. Residences
2. Schools
3. Hospitals
4. Rest homes
5. Long term medical or mental care facilities
6. Other uses deemed noise sensitive by the local jurisdiction

A Technical Reference Report, on file in the Planning Department, describes the effects of noise on people and techniques for noise control. It also includes data from the community noise survey and highway noise evaluation.

2.0 EXISTING AND FUTURE NOISE ENVIRONMENT

2.1 OVERVIEW OF NOISE IN SONOMA COUNTY

2.1.1 Noise and its Effects on People

Noise is defined as unwanted sound. Existing noise descriptors are the result of many years of trying to quantify subjective reactions. Loudness is dependent upon many factors, including sound pressure level and frequency. "Weighting" these factors can help to accurately measure actual human response to noise. The "A-weighted" filter developed by the Environmental Protection Agency has become the standard tool of environmental noise assessment.

Noise has often been cited as a health problem because it inhibits general well being and contributes to undue stress and annoyance. Noise interferes with sleep, speech, recreation, and tasks demanding concentration or coordination. The result is an increase in public annoyance with the noise source and a decrease in environmental quality.

In very quiet environments, virtually any change in local activities will cause an increase in noise levels and a loss of "peace and quiet". Such increases may be considered significant by residents in these areas, even if the measured increase is small.

Table NE-1 shows the expected public reaction to change in noise levels. Because reaction may differ in very quiet environments, Table NE-1 is only a general indicator of the relationship between changes in noise and subjective reaction.

Table NE-1 Subjective Reaction to Changes in Noise Levels of Similar Sources

Sources: Various, reported by Brown-Buntin Associates

Note: All noise levels in this element are expressed in decibels. The term "dBA" means the decibel level as measured through the "A-weighted" noise filter developed by the EPA. Additional information regarding noise measurement, statistical descriptions, and criteria for acceptable noise exposure is provided in the Technical Reference Report.

2.1.2 Noise Sources in Sonoma County

Potentially significant sources of community noise within Sonoma County include:

All State Highways
Selected County Arterial and Collector Highways
Public-use Airports
Northwest Pacific Railroad (NWPRR) line operations
Sears Point International Raceway
Lumber processing operations
Mineral extraction operations
Asphalt and concrete batch plants
Gas well compressors
The Geysers geothermal power plants
Solid waste landfills and transfer stations
Agricultural operations
Concerts, special events and other activities generating amplified outdoor sound

2.1.3 Methods of Noise Analysis

Existing and projected noise level contours are based upon an analysis of source-specific data such as average levels of activity, hours of operation, seasonal changes, and measured noise levels. Analytical methods were used for a number of noise sources including roadways, raillines and railroad yards, industrial plants and aircraft.

These methods closely follow the recommendations of the State Office of Noise Control and were supplemented by field measured noise levels. The Ldn contours resulting from the analysis are based upon annual average conditions and are not intended to reflect site specific factors. Noise levels were not analyzed for concerts and special events because of their varied timing, settings and noise levels.

2.1.4 Community Noise Survey

A community noise survey was conducted by Brown-Buntin Associates to measure noise exposure in areas with residences and other noise sensitive land uses. Noise monitoring was conducted at representative sites during three periods of the day and night on May 28 and 29, 1986. Two sites were selected for 24 hour monitoring to establish any trend during this period. The sites, levels, and values at each site are summarized in the Technical Reference Report and on Figure NE-1 on page 397.

The survey results showed typical levels in noise sensitive areas in the range of 40-50 dB Ldn, except along the coastline where the surf produces higher levels. Traffic is the primary background noise generator in most areas. Topography shields some residential areas from noise, lowering ambient levels to 45 dB Ldn or less. In general, areas with noise sensitive uses in Sonoma County are very quiet except along major highways and near airports.

During the noise monitoring period, jet aircraft overflights were noted in areas near Sonoma County Airport. The occasional military jet overflights appear to be at relatively high altitude, reducing the noise impacts of individual overflights. Another noise source noted during the survey was heavy truck traffic on small county roads, usually from timber, agriculture or mining activities. Passage of these vehicles in a rural setting is a significant noise event.

2.2 HIGHWAY RELATED NOISE

The noise analysis developed Ldn contours for State highways and selected major roads in the County. Noise measurements were also taken at five locations along State Highways to verify the method of analysis. Traffic counts and projections were used to obtain hourly traffic volumes. In general, the Federal Highway Administration model used in the analysis slightly overestimated traffic noise levels in Sonoma County.

Traffic data for existing and future conditions were obtained from Caltrans and the Sonoma County Public Works Department. Future traffic volumes are from the Circulation and Transit Element. Traffic noise levels (Ldn) were calculated for existing and projected 2005 traffic volumes.

Noise contours do not account for shielding caused by local buildings or topographical features and should therefore be considered as worst case estimates of noise exposure along roadways. Maps showing these contours are on file in the Planning Department. Noise significant roadways are shown in Figure NE-1 on page 397.

2.3 AIRPORT RELATED NOISE

Aircraft noise near airports typically consists of brief, noisy events separated by periods of relative quiet. The California Administrative Code defines the 65 dB CNEL contour around airports as the "Noise Impact Boundary" for maximum exposure of airport noise, but the Air Transportation Element uses 60 dB CNEL as the maximum allowed in residential areas because most of the airports are located in relatively quiet rural areas.

Noise levels around Sonoma County airports were measured in 1986 during preparation of the Air Transportation Element and are described in a technical report for that element. Most of the aircraft noise in the county is currently generated by large numbers of small single engine aircraft. Jets and other large aircraft do not contribute significantly to the present CNEL contours. However, the high noise level of landings and takeoffs by certain large aircraft may cause an adverse impact in quiet rural settings. Thus, the substantial number of business jet and large piston engine operations at Sonoma County Airport extend the Airport's computed 60 CNEL contour, particularly under the instrument approach zones. Projected future levels of airport operations and resulting noise are shown in the Air Transportation Element.

2.4 RAILROAD NOISE

Railroad operations consist of through freight and local switching operations by the Northwestern Pacific Railroad. Railroad scheduling varies with seasonal demands and other economic factors, but the main line averages two trains per day several days per week. Through trains usually have one or two locomotives with 20 to 90 cars, depending upon shipping demands. Local trains are generally shorter. Whether the number of railroad operations will change significantly in the future is unknown.

Noise levels from railroad operations were evaluated based upon the worst case assumption of two trains during daytime hours and two trains at night. The CNEL from this level of operation would exceed 60 dBA within about 300 feet of the tracks. At distances of about 100 feet from the tracks, maximum noise levels from trains would range from 80 to 90 dBA. Ldn contours for railroad operations are available at the Sonoma County Planning Department.

2.5 SEARS POINT INTERNATIONAL RACEWAY

The Sears Point Raceway has both road racing and drag racing. The race schedule includes a variety of professional and amateur road races, motorcycle races, classic car meets, go-kart races, car club outings and drag racing. Sears Point also has a race driving school Monday through Thursday. Most racing events occur on weekend days.

Maximum noise level contours for worst case drag racing activities were prepared. Of all the racing activities, drag racing is the noisiest. Control measures for drag racing are limited to shielding by barriers or topography, curfews, or prohibition of racing.

For other types of racing, mufflers may be a viable means of noise control, if required on a regional or national basis. The SCCA and the AMA, for example, impose muffler requirements on autos and motorcycles competing in events sanctioned by those bodies. Other sanctioning bodies, however, have no such requirement. As a result, it is very important to separate noise sensitive land uses from the raceway.

2.6 INDUSTRIAL NOISE SOURCES

Noise is part of many industrial processes, even when the best noise control measures are applied. Exterior noise from industrial operations may exceed local standards near noise sensitive land uses.

Performance standards may be applied to proposed new industrial uses to reduce the potential for noise impacts in noise sensitive areas. Measures may also be applied to new noise sensitive uses near existing industrial facilities.

2.6.1 Representative Industrial Sources

The following industrial sources produce the most significant impacts of industrial uses in Sonoma County. These uses are also specific noise sources which should be considered in the review of nearby development proposals. The general locations of these noise sources are shown on Figure NE-1 on page 397. The 60 dB Ldn noise contours for all of these sources appear to fall within site boundaries.

Wood Processing Operations: Six large wood processing operations are located in unincorporated areas in the Highway 101 urban corridor, five near Cloverdale and one south of Windsor. Noise sources include fans, cyclones, saws, loaders, sorters, forklifts, chippers and trucks. Most noise impacts occur on weekdays between 6 a.m. and 4 p.m. but some operations occur at night and on weekends, particularly during summer.

Figure NE-1

View full size FIGURE NE-1

Asphalt Batch Plant: Operation of a gas-fired asphalt batch plant located south of Cloverdale has resulted in several complaints. The primary noise source at this facility is a gas burner which produces low frequency sounds with a measured noise level of 79 decibels within site boundaries. The computed 60 CNEL contour also is within the boundaries of the site.

Gas Well: A gas well located south of Sebastopol was considered a potential noise source when it was installed but has not proved significant. Because the compressor is completely enclosed and the engine exhaust is ducted through the top of the building, the operation is barely audible at 100 feet.

2.6.2 Wineries

There are over 120 commercial wineries in unincorporated Sonoma County, varying in production from several thousand to more than a million gallons per year. Wineries are typically located in very quiet rural areas where ambient noise is low. Exterior noise generated at wineries occurs during the crush season and is usually less than 60 dBA at distances greater than 300 feet.

2.6.3 Potential New Industrial Noise Sources

Potential new industrial noise sources other than wineries will be located in the areas designated for industrial use. Projects in those locations and in adjacent residential areas will be reviewed for consistency with the performance standards in this element.

2.7 NOISE ASSOCIATED WITH MINERAL EXTRACTION

The development of mineral resources is subject to the policies of the Aggregate Resources Management Plan. The Plan indicates areas where mineral resources may be mined. These areas should be considered as potential noise sources during review of proposed noise sensitive uses at nearby sites. Noise sources are either mobile or stationary and could have long term effects on neighboring properties. Blasting may occur during the normal operation of hillside quarries.

Sonoma County Ordinance No. 3437 regulates surface mining and reclamation and includes noise standards which are applied to mining operations. The ordinance allows more stringent requirements when local circumstances warrant additional protection.

The performance standards of this element are complementary to and consistent with Ordinance No. 3437.

2.8 NOISE ASSOCIATED WITH GEOTHERMAL DEVELOPMENT

There are over 20 geothermal power plants in the Geysers area in both Sonoma and Lake Counties. Noise is generated by release of steam during drilling and for pressure relief. During steam release, cyclonic separators emit noise levels up to 90 dBA at 50 feet. Both rock mufflers and truck mounted mufflers can be used to reduce steam release noise, but this noise is of short duration and infrequent.

Under normal conditions, operation of power plants produces relatively constant noise from cooling tower fans and trucks. The remote location of the Geysers area and the absence of nearby residential areas limits land use conflicts due to geothermal plant noise. The County has set a noise limit of 65 dBA at the boundaries of each leasehold.

2.9 NOISE ASSOCIATED WITH SOLID WASTE DISPOSAL

Solid waste disposal and transfer facilities produce heavy equipment and truck noise. At transfer stations, onsite noise may be produced by user vehicles but the most significant noise sources are the haul truck and front loaders. The access roads for landfills and transfer stations may be significant sources of community noise due to the large volume of vehicles.

Noise impacts are limited to daytime. The Central Landfill and Healdsburg Landfill were evaluated for this element. Noise contour maps are available at the Planning Department. The 60 dB Ldn contours are within the site boundaries for both facilities.

3.0 NOISE ISSUES, POLICIES AND STANDARDS

3.1 LAND USE COMPATIBILITY AND PROJECT REVIEW

Noise level performance standards in Table NE-2 below are to be applied as performance standards for noise producing land uses which may affect noise sensitive land uses and vice versa.

Infrequent single events such as passage of a train, truck, or airplane may interfere with adjacent uses even though the cumulative noise exposure is within acceptable limits. These events call for a single event noise standard. The potential for sleep disturbance is often the main concern in these cases.

GOAL NE-1: Protect people from the harmful effects of exposure to excessive noise and to achieve an environment in which people and land uses may function without impairment from noise.

Objective NE-1.1: Provide noise exposure information so that noise impacts may be effectively evaluated in land use planning and project review.

Table NE-2 Noise Level Performance Standards

Objective NE-1.2: Develop and implement measures to avoid exposure of people to excessive noise levels.

Objective NE-1.3: Protect the present noise environment and prevent intrusion of new noise sources which would substantially alter the noise environment.

Objective NE-1.4: Mitigate noise from recreational and tourist serving uses.

The following policies shall be used to achieve the above objectives.

NE-1a: Designate areas within Sonoma County as noise impacted if they are exposed to existing or projected exterior noise levels exceeding 60 dB Ldn, 60 dB CNEL, or the performance standards of Table NE-2 above.

NE-1b: Avoid noise sensitive land use development in noise impacted areas unless effective measures are included to reduce noise levels. For noise due to traffic on public roadways, railroads and airports, reduce exterior noise to 60 dB Ldn or less in outdoor activity areas and interior noise levels to 45 dB Ldn or less with windows and doors closed. Where it is not possible to meet this 60 dB Ldn standard using a practical application of the best available noise reduction technology, a maximum level of up to 65 dB Ldn may be allowed but interior noise level shall be maintained so as not to exceed 45 dB Ldn.

NE-1c: Control non transportation related noise from new projects. The total noise level resulting from new sources and ambient noise shall not exceed the standards in Table NE-2 as measured at the exterior property line of any affected residential land use. Limit exceptions to the following:

1) If the ambient noise level exceeds the standard in Table NE-2, adjust the standard to equal the ambient level.

2) Reduce the applicable standards in Table NE-2 by five dBA for simple tone noises, noises consisting primarily of speech or music, or for recurring impulsive noises.

3) Reduce the applicable standards in Table NE-2 by 5 decibels if they exceed the ambient level by 10 or more decibels.

NE-1d: Consider requiring an acoustical analysis prior to approval of any discretionary project involving a potentially significant new noise source or a noise sensitive land use in a noise impacted area. The analysis shall:

1) be the responsibility of the applicant

2) be prepared by a qualified acoustical consultant

3) include noise measurements adequate to describe local conditions

4) include estimated noise levels in terms of Ldn and/or the standards of Table NE-2 for existing and projected future (20 years hence) conditions, with a comparison made to the adopted policies of the Noise Element

5) recommend measures to achieve compliance with this element. Where the noise source consists of intermittent single events, address the effects of maximum noise levels on sleep disturbance

6) include estimates of noise exposure after these measures have been implemented.

7) be reviewed by the Health Department.

NE-1e: Establish building permit procedures to ensure that requirements based upon the acoustical analysis are implemented.

NE-1f: Require development projects which do not include or affect residential uses or other noise sensitive uses to include noise mitigation measures where necessary to maintain noise levels compatible with activities planned for the project site and vicinity.

NE-1g: Enforce the State Noise Insulation Standards and Chapter 35 of the Uniform Building Code concerning new multiple occupancy dwellings.

NE-1h: Prepare and consider a noise control ordinance to regulate existing noise sources as follows:

1. the draft ordinance shall be prepared by County Counsel with the assistance of the Public Health and Planning Departments.

2. consider ONC guidelines and ordinances of other counties

3. the intent of the ordinance shall be to protect persons from existing or future excessive levels of noise which interfere with sleep, communication, relaxation, health or legally permitted use of property.

4. "excessive" levels of noise shall be defined as levels which exceed the standards of Table NE-2 and other policies of the Noise Element.

5. in unincorporated areas of the County, it shall be unlawful to create noise which exceeds the standards of Table NE-2, as measured at the exterior of any noise sensitive use.

6. the noise ordinance may contain maximum allowable levels of interior noise created by exterior sources.

7. the ordinance may exempt or modify noise requirements for agricultural uses, construction activities, school functions, property maintenance, heating and cooling equipment, utility facilities, waste collection and other sources.

8. the ordinance shall include responsibilities and procedures for enforcement, abatement and variances.

NE-1i: County equipment and vehicles shall comply with adopted noise level performance standards consistent with the best available noise reduction technology.

NE-1j: Encourage the California Highway Patrol to actively enforce sections of the California Vehicle Code relating to adequate vehicle mufflers and modified exhaust systems.

NE-1k: Incorporate into the zoning ordinance the standards and policies of the Noise Element where appropriate.

NE-1l: Review and update the Noise Element to ensure that noise information and policies are consistent with regulations and conditions within the community.

NE-1m: Consider requiring the monitoring of noise levels for discretionary projects to determine if noise levels are in compliance with required standards. The cost of monitoring shall be the responsibility of the applicant.

3.2 MANAGEMENT OF TRANSPORTATION RELATED NOISE

Transportation sources are by far the most significant sources of environmental noise in Sonoma County. They include vehicular traffic, especially trucks, rail operations, and aircraft overflights in the approach areas to airports. Figure NE-1 on page 393 shows major highways, railroads, and public use airports. An important part of planning for a healthful environment is the avoidance of unnecessary transportation noise. The Circulation and Transit Element includes policies intended to reduce traffic congestion and keep traffic flowing smoothly, thereby helping lower expected future noise levels. The Air Transportation Element includes policies limiting noise exposure from aircraft operations.

GOAL NE-2: Confine the noise impacts from transportation facilities to the smallest feasible land areas and to assure that any development therein be compatible with the level of noise exposure.

Objective NE-2.1: Design and manage transportation systems to produce the lowest feasible noise levels and impacts on noise sensitive land uses.

Objective NE-2.2: Provide highway, railroad, and air transportation systems and services so that the boundaries of their projected 60 dBA noise contours for 2005 are not extended.

The following policies, in addition to those of the Air Transportation and Circulation and Transit Elements, shall be used to achieve these objectives:

NE-2a: County departments shall make available to the public all maps or data on hand concerning the existing or future noise levels generated by transportation sources.

NE-2b: Encourage installation of sound barriers along roadways in non industrial urban areas where an exterior noise level of 65 dB Ldn or more is attained and residences or other noise sensitive uses exist.

NE-2c: Consider using truck routing, speed limits, signal timing and other traffic control measures to reduce impacts on noise sensitive uses.

NE-2d: Consider measures to reduce peak traffic volumes as a means to reduce highway related noise.

NE-2e: Where practical, select route alignments for new roadways and major improvements to existing highways to avoid or minimize noise impacts on noise sensitive land uses.

NE-2f: Where practical, include noise control measures in County funded construction of new roadways and additional through travel lanes to maintain noise compatibility with noise sensitive land uses. The goal of these measures shall be to prevent the road project from causing the total exterior noise level to increase above 60 dBA Ldn, as estimated adjacent to dwellings and other "noise-sensitive" primary uses. Where full implementation of such measures is not possible, desirable or appropriate, the reasons for that determination shall be stated clearly by County decision makers.

4.0 NOISE ELEMENT IMPLEMENTATION PROGRAM:

Noise Element Program 1: Incorporate Noise Analysis in to the Permit Review Procedures

Program Description: Special permit review procedures will be established for projects which involve generation of significant noise levels and projects which are located in noise-impacted areas. Acoustical reports may be prepared and mitigating measures required for projects. Noise attenuation measures may be included in the design review manual.

Noise Element Program 2: Adopt a Noise Ordinance

Program Description: Preparation of draft ordinance by County Counsel and Planning and Public Health Departments. Ordinance to include noise performance standards expressed in Table NE-2 on page 400, and others as appropriate. Exemptions, measurement methods, and procedures for variances and enforcement are to be included.