N OISE I MPACT A NALYSIS

Transcription

1 N OISE I MPACT A NALYSIS FOR B EAR R IVER A MENDMENT P ROJECT Y UBA C OUNTY, CA PREPARED BY: 5314 SHELATO WAY CARMICHAEL, CA CONTACT: KURT LEGLEITER TEL/FAX: December 11, 2006

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3 INTRODUCTION This section of the EIR includes a description of ambient noise conditions in the project vicinity, a summary of applicable regulations, and an analysis of potential noise impacts associated with the proposed project. Mitigation measures are recommended, as necessary, to reduce significant noise impacts. ENVIRONMENTAL SETTING CONCEPTS AND TERMINOLOGY Acoustic Fundamentals Noise is generally defined as sound that is loud, disagreeable, or unexpected. Sound, as described in more detail below, is mechanical energy transmitted in the form of a wave because of a disturbance or vibration. Amplitude Amplitude is the difference between ambient air pressure and the peak pressure of the sound wave. Amplitude is measured in decibels (db) on a logarithmic scale. For example, a 65 db source of sound, such as a truck, when joined by another 65 db source results in a sound amplitude of 68 db, not 130 db (i.e., doubling the source strength increases the sound pressure by 3 db). Amplitude is interpreted by the ear as corresponding to different degrees of loudness. Laboratory measurements correlate a 10 db increase in amplitude with a perceived doubling of loudness and establish a 3 db change in amplitude as the minimum audible difference perceptible to the average person (US EPA 1971). Frequency Frequency is the number of fluctuations of the pressure wave per second. The unit of frequency is the Hertz (Hz). One Hz equals one cycle per second. The human ear is not equally sensitive to sound of different frequencies. Sound waves below 16 Hz or above 20,000 Hz cannot be heard at all, and the ear is more sensitive to sound in the higher portion of this range than in the lower. To approximate this sensitivity, environmental sound is usually measured in A-weighted decibels (dba). On this scale, the normal range of human hearing extends from about 10 dba to about 140 dba (US EPA 1971). Characteristics of Sound Propagation and Attenuation Noise can be generated by a number of sources, including mobile sources, such as automobiles, trucks and airplanes, and stationary sources, such as construction sites, machinery, and industrial operations. Noise generated by mobile sources typically attenuates at a rate between 3.0 to 4.5 dba per doubling of distance. The rate depends on the ground surface and the number or type of objects between the noise source and the receiver. Mobile transportation sources, such as highways, hard and flat surfaces, such as concrete or asphalt, have an attenuation rate of 3.0 dba per doubling of distance. Soft surfaces, such as uneven or vegetated terrain, have an attenuation rate of about 4.5 dba per doubling of distance from the source. Noise generated by stationary sources typically attenuates at a rate of approximately 6.0 to 7.5 dba per doubling of distance from the source (US EPA 1971). Yuba County 1 January 11, 2007

4 Sound levels can be reduced by placing barriers between the noise source and the receiver. In general, barriers contribute to decreasing noise levels only when the structure breaks the "line of sight" between the source and the receiver. Buildings, concrete walls, and berms can all act as effective noise barriers. Wooden fences or broad areas of dense foliage can also reduce noise, but are less effective than solid barriers. Noise Descriptors The selection of a proper noise descriptor for a specific source is dependent upon the spatial and temporal distribution, duration, and fluctuation of the noise. The noise descriptors most often encountered when dealing with traffic, community, and environmental noise are defined below (Lipscomb and Taylor 1978). Maximum Noise Level (Lmax): The maximum instantaneous noise level during a specific period of time. Minimum Noise Level (Lmin): The minimum instantaneous noise level during a specific period of time. Energy Equivalent Noise Level (Leq): The energy mean (average) noise level. The instantaneous noise levels during a specific period of time in dba are converted to relative energy values. From the sum of the relative energy values, an average energy value (in dba) is calculated. Day-Night Noise Level(Ldn): The 24-hour Leq with a 10 dba penalty for noise events that occur during the noise-sensitive hours between 10:00 p.m. and 7:00 a.m. In other words, 10 dba is added to noise events that occur in the nighttime hours to account for increases sensitivity to noise during these hours. Community Noise Equivalent Level (CNEL): The CNEL is similar to the Ldn described above, but with an additional 5 dba penalty added to noise events that occur between the hours of 7:00 p.m. to 10:00 p.m. The calculated CNEL is typically approximately 0.5 dba higher than the calculated Ldn. Single Event Noise Level (SEL): The SEL describes a receiver s cumulative noise exposure from a single noise event, which is defined as an acoustical event of short duration and involves a change in sound pressure above a reference value. Human Response to Noise The human response to environmental noise is subjective and varies considerably from individual to individual. Noise in the community has often been cited as a health problem, not in terms of actual physiological damage, such as hearing impairment, but in terms of inhibiting general well-being and contributing to undue stress and annoyance. The health effects of noise in the community arise from interference with human activities, including sleep, speech, recreation, and tasks that demand concentration or coordination. Hearing loss can occur at the highest noise intensity levels. When community noise interferes with human activities or contributes to stress, public annoyance with the noise source increases. The acceptability of noise and the threat to public well-being are the basis for land use planning policies preventing exposure to excessive community noise levels. Typical community noise levels are depicted in Exhibit 1. Yuba County 2 January 11, 2007

5 INDOORS A-Weighted Decibels Perceived Loudness Relative to 60 dba OUTDOORS Threshold of Pain 140 x256 Military Jet Takeoff with Afterburner (at 50 feet) 130 x128 Deafening 120 x64 Jet Takeoff at 200 Feet Rock Band Inside Subway Train, New York Uncomfortably Loud 110 x x Takeoff (4 Miles From Start of Roll) Power Lawnmower (at 50 Feet) Ambulance Siren (at 100 Feet) Noisy Cocktail Bar Jet Aircraft Cabin, at Cruise Shouting (at 3 Feet) Noisy Restaurant Vacuum Cleaner at 3 Feet Large Business Office Normal Conversation (at 3 Feet) Quiet Office Quiet Library Concert Hall, Background Recording Studio 90 x8 Very Loud 80 x4 Moderately Loud 70 x2 60 x1 Moderately Quite 50 x1/2 40 x1/4 30 x1/8 Very Quiet 20 x1/16 Barely Audible 10 x1/32 0 Threshold of Hearing x1/ Takeoff (4 Miles From Start of Roll) Diesel Truck, 40 mph (at 50 Feet) Automobile, 65 mph (at 50 Feet) Busy Street (at 50 Feet) Takeoff (4 Miles From Start of Roll) Automobile, 30 mph (at 50 Feet) Cessna 172 Landing (3,300 Feet From Rwy End) Quiet Urban Area, Nighttime Quiet Suburban Area, Nighttime Quiet Rural Area, Nighttime Leaves Rustling Sources: California Department of Transportation, January 2002, California Airport Land Use Planning Handbook; M. David Egan, McGraw Hill, 1972, Concepts in Architectural Acoustics; and U.S. Department of Housing and Urban Development, Office of Community Planning and Development, The Noise Guidebook. EXHIBIT 1: TYPICAL COMMUNITY NOISE LEVELS Yuba County 3 January 11, 2007

6 Unfortunately, there is no completely satisfactory way to measure the subjective effects of noise or of the corresponding reactions of annoyance and dissatisfaction. This is primarily because of the wide variation in individual thresholds of annoyance and habituation to noise over differing individual experiences with noise. Thus, an important way of determining a person s subjective reaction to a new noise is the comparison of it to the existing environment to which one has adapted: the so-called ambient environment. In general, the more a new noise exceeds the previously existing ambient noise level, the less acceptable the new noise will be judged. Regarding increases in A-weighted noise levels, knowledge of the following relationships will be helpful in understanding this analysis: Except in carefully controlled laboratory experiments, a change of 1 db cannot be perceived by humans. Outside of the laboratory, a 3-dB change is considered a just-perceivable difference. A change in level of at least 5 db is required before any noticeable change in community response would be expected. An increase of 5 db is typically considered substantial. A 10-dB change is subjectively heard as an approximate doubling in loudness and would almost certainly cause an adverse change in community response. When evaluating noise impacts, based on the above relationships, it is generally recognized that an increase of greater than 3 dba is considered potentially significant. However, increases in ambient noise levels need to also take into account the existing noise environment. Consequently, increases in cumulative noise exposure (in CNEL/Ldn) of 5 dba are generally considered significant in areas where the ambient noise environment is less than 60 dba. In areas where the ambient noise environment is between 60 and 65 dba, increases of 3.0 dba, or greater, would be considered significant. In areas where the ambient noise environment exceeds 65 dba, a predicted increase of 1.5 dba, or greater, would be considered significant. These thresholds were initially recommended by the Federal Interagency Committee on Noise (FICON) in 1972, based on noise levels at which people typically become increasingly annoyed. These recommendations have since been recognized by various local, state and federal agencies and are the criteria typically used for the analysis of increases in ambient noise levels (FAA, 2000). EXISTING NOISE-SENSITIVE LAND USES Noise-sensitive land uses are generally considered to include those uses which would result in noise exposure that could result in health-related risks to individuals, as well as places where quiet is an essential element of their intended purpose. Residential dwellings, including senior housing, are of primary concern because of the potential for increased and prolonged exposure of individuals to both interior and exterior noise levels. Additional land uses such as parks, historic sites, cemeteries, and recreation areas are also considered sensitive to increases in exterior noise levels. Schools, churches, hotels, libraries, and other places, where low interior noise levels are essential, are also considered noise-sensitive land uses. Existing noise-sensitive receptors in the vicinity of the project site consist primarily of residential land uses located along its western and southern boundaries. Mary Buren Elementary School is located south of the project site, at the southeastern corner of 11 th Street and Peralta Street. Noise-sensitive land uses are identified in Exhibit 2. Yuba County 4 January 11, 2007

7 AMBIENT NOISE SURVEY To document the existing noise environment, ambient noise surveys were conducted by at various locations in the project area. Short-term (10- minute) noise level measurements were conducted using a Larson Davis model 820 sound-level meter placed at a height of approximately 4.5 feet above the ground surface. Based on the measurements conducted, average daytime noise levels (in dba Leq) in the project area generally range from the upper 30s to upper 50s, dependent primarily on distance from nearby roadways. Measurement locations and corresponding maximum measured daytime noise levels are depicted in Exhibit 2. Measurement survey results are summarized in Table 1. The dominant noise source noted during the survey was vehicular traffic on area roadways, including Feather River Boulevard. Activities conducted at the nearby Danna & Danna, Inc. fruit processing facility also contributed to ambient noise levels along the western boundary of the project site. Noise generated by these existing noise sources are discussed in more detail, as follows: Danna & Danna Inc., Fruit Processing Facility The Danna & Danna Inc., fruit processing facility is located approximately 350 feet west of the project site boundary (refer to Exhibit 2). Activities conducted at this facility include prune drying and walnut hulling and drying. The facility typically operates approximately twelve hours a day, between the daytime hours of 6 a.m. and 6 p.m. Peak operational periods generally occur three months per year, during the months of August through October. Noise sources at this facility are primarily associated with the onsite operation of motorized equipment (i.e., forklifts, tractors, and haul trucks) and material loading and unloading activities. During peak operational months (i.e., August through October) the facility averages approximately 12 trucks per day. Stationary equipment, including the hulling machine and fan motors used for dryers, are located within enclosed buildings and/or shielded from direct line-of-sight to the proposed project site (pers. com., Dana 2007). Noise surveys were conducted along the western boundary of the project site and in the vicinity of the fruit processing facility during non-peak and peak operational periods of the year. Onsite stationary processing equipment was detectable, but was not found to contribute substantially to overall noise generated by this facility, as perceived at the western boundary of the project site. Measured noise levels from this facility were largely influenced by the onsite operation of motorized equipment, including forklifts, tractors, and trucks. Measured average-hourly daytime noise levels obtained at the western boundary of the project site ranged from a low of approximately 39 dba Leq during the month of January to a high of approximately 46 dba Leq during the month of October. Yuba County 5 January 11, 2007

8 TABLE 1 AMBIENT DAYTIME NOISE LEVELS 1 Project Site, Western Boundary Measured Noise Level (dba) Location Date/Time Noise Sources Noted During Survey Leq Lmin Lmax 2 Project Site, Southern Boundary 3 Project Site, Eastern Boundary July 27, 2006; 14:10-14:20 Onsite Equipment at Danna & Danna, Inc October 26, 2006; 10:05-10:15 Onsite Equipment at Danna & Danna, Inc January 9, 2007; 16:05-16:15 Onsite Equipment at Danna & Danna, Inc July 27, 2006; 13:35-13:45 Vehicle Traffic on Feather River Blvd October 26, 2006; 9:10-9:20 Vehicle Traffic on Feather River Blvd January 9, 2007; 15:20-15:30 Vehicle Traffic on Feather River Blvd July 27, 2006; 13:10-13:20 Vehicle Traffic on Feather River Blvd October 26, 2006; 8:40-8:50 Vehicle Traffic on Feather River Blvd January 9, 2007; 15:00-15:10 Vehicle Traffic on Feather River Blvd Noise measurement locations correspond to those identified in Exhibit 2 of this report. Measurement site 1 was located at the approximate boundary of the project site. Measurement locations 2 and 3 were located approximately 50 feet from near travel lane centerline of Feather River Boulevard. Yuba County 6 January 11, 2007

9 Image Source: USGS 2006 Feather River Boulevard N Not to Scale Ambient Noise Monitoring Locations 1 Noise Measurement Locations Leq Lmin Lmax Average-Hourly Energy-Equivalent Noise Levels Minimum Noise Levels Maximum Noise Levels Noise measurement locations correspond to those identified in Table 2 of this report. Depicted noise levels represents range of measured maximum daytime noise levels, based on short-term noise measurements conducted on July 27, 2006, October 26, 2006, and January 9, Measurement site 1 was located at the approximate boundary of the project site and measurement locations 2 and 3 were located approximately 50 feet from roadway centerline. EXHIBIT 2: AMBIENT NOISE ENVIRONMENT

10 Roadway Traffic Noise Table 2 summarizes the existing traffic noise levels (in dba CNEL) at 50 feet from the near travel lane centerline for existing traffic conditions. Existing roadway traffic noise levels were calculated for these roadway segments using the Federal Highway Administration (FHWA) traffic noise prediction model. Traffic data used in the analysis were obtained from the traffic analysis prepared for this project. Additional input data included day/night percentages of autos, medium and heavy trucks, vehicle speeds, ground attenuation factors, and roadway widths. Based on the modeling conducted, traffic noise levels along area roadways generally range from the lower 50 s to the lower 60 s at 50 feet from the centerline of the near travel lane. TABLE 2 SUMMARY OF EXISTING TRAFFIC NOISE LEVELS Roadway Segment and Location Ldn/CNEL (dba) 50 ft from Near Travel Lane Centerline Plumas Arboga Rd, West of SR Feather River Blvd, S of Algodon Road Feather River Blvd, West of River Oaks Blvd Feather River Blvd, East of River Oaks Blvd River Oaks Blvd., N. of Feather River Blvd Traffic noise levels were predicted using the FHWA Traffic Noise Model based on data obtained from the traffic analysis prepared for this project. Predicted noise levels do not take into account shielding provided by intervening structures or existing noise barriers. REGULATORY SETTING STATE OF CALIFORNIA The State of California regulates vehicular and freeway noise affecting classrooms, sets standards for sound transmission and occupational noise control, and identifies noise insulation standards and airport noise/land-use compatibility criteria. The State of California General Plan Guidelines (State of California 1998), published by the Governor s Office of Planning and Research (OPR), also provides guidance for the acceptability of projects within specific Ldn/CNEL contours. The guidelines also present adjustment factors that may be used in order to arrive at noise acceptability standards that reflect the noise control goals of the community, the particular community s sensitivity to noise, and the community s assessment of the relative importance of noise pollution. Table 3 summarizes the acceptable and unacceptable community noise exposure limits for various land use categories, as currently defined by the State of California. Title 24 of the California Code of Regulations establishes standards governing interior noise levels that apply to all new multifamily residential units in California. These standards require that acoustical studies be performed prior to construction at building locations where the existing Ldn/CNEL exceeds 60 dba. Such acoustical studies are required to establish mitigation measures that will limit interior noise levels to 45 dba CNEL. Yuba County 8 January 11, 2007

11 TABLE 3 STATE OF CALIFORNIA LAND USE COMPATIBILITY FOR COMMUNITY NOISE ENVIRONMENTS Land Use Residential Uses Low Density Single Family, Duplex, Mobile Homes Normally Acceptable Noise Levels (dba CNEL/ Ldn) Conditionally Normally Acceptable Unacceptable Clearly Unacceptable < to to 75 > 75 Residential Multi-Family < to to 75 > 75 Transient Lodging, Hotels, Motels < to to 80 > 80 Schools, Libraries, Churches, Hospitals, Nursing Homes < to to 80 > 80 Auditoriums, Concert Halls, Amphitheaters < 70 >65 Sports Arena, Outdoor Spectator Sports < 75 >70 Playgrounds, Neighborhood Parks < to 75 > 72.5 Golf Courses, Riding Stables, Water Recreation, Cemeteries < to 80 > 80 Office Buildings, Business, Commercial, Professional < to 77.5 > 75 Industrial, Manufacturing, Utilities, Agricultural < to 80 > 75 Normally Acceptable: Specified land use is satisfactory, based upon the assumption that any buildings involved are of normal conventional construction, without any special noise insulation requirements. Conditionally Acceptable: New construction or development should be undertaken only after a detailed analysis of the noise reduction requirements is made and needed noise insulation features included in the design. Conventional construction, but with closed windows and fresh air supply systems or air conditioning will normally suffice. Normally Unacceptable: New construction or development should generally be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements must be made and needed noise insulation features included in the design. Clearly Unacceptable: New construction or development should generally not be undertaken. Source: State of California 2003 YUBA COUNTY The Noise Element of the Yuba County General Plan contains policies designed to protect the community from the harmful and annoying effects of exposure to excessive noise. The noise element contains objectives for acceptable noise exposure, based on land use designation. The County s recommended noise exposure criteria are depicted in Table 4. The Noise Element does not specify if the noise level objectives contained in Table 4 represent maximum or average noise levels. It is most likely that the standards were intended to represent average hourly noise levels (Leq). To assess noise levels due to transportation noise sources, Ldn or CNEL descriptors are most commonly used. Although the Noise Element does not contain noise standards in terms of these descriptors, County staff has stated that these descriptors are commonly used to assess traffic noise impacts in Yuba County, consistent with those recommended by the State of California (Table 3). The goals, policies, and objectives of the County General Plan pertaining to noise, as well as the proposed project s consistency with these policies, are summarized in Table 5. Yuba County 9 January 11, 2007

12 TABLE 4 YUBA COUNTY NOISE EXPOSURE STANDARDS Land Use Noise Exposure Level (dba) 7 a.m. to 10 p.m. 10 p.m. to 7 a.m. Low Density Residential Multi-Family Residential School Retail/Commercial Passive Recreation Area Active Recreation Area Hospitals/Mental Facilities Agriculture Neighborhood Commercial Professional Office Light Manufacturing Heavy Manufacturing Source: Yuba County 1980 TABLE 5 PROJECT CONSISTENCY WITH THE YUBA COUNTY GENERAL PLAN - NOISE Goals and Policies Consistency with General Plan Analysis Goal: The general goal is to protect the lives and property of the citizens of Yuba County from hazardous and annoying noise. Implementation 3: Yuba County shall maintain strict enforcement of sound insulation standards for all new construction as required by the most current Uniform Building Code. Yes Sound insulation standards for new construction are required as a part of the building permit process and UBC. Implementation 5: Yuba County shall control all developments proposed near highways, railroads lines and airports to protect the residents of Yuba county from excessive annoying noise and to preserve the existing land uses. Implementation 6: Yuba County shall require that noise studies be prepared on noise generating uses that are proposed for development in noise sensitive areas to determine land use compatibility. Implementation 7: Yuba County shall assure that population densities and development are kept to a minimum in areas of known excessive noise generation. Yes The project proposes office and industrial uses within the project site that is within the 65 CNEL aircraft noise contour, no residential uses are proposed within the 65 CNEL. Yes A noise impact study was prepared for this EIR. Yes Refer to Implementation 5 consistency analysis above. Ground-Borne Vibration There are no federal, state, or local regulatory standards for ground-borne vibration. However, various criteria have been established to assist in the evaluation of vibration impacts. For instance, the California Department of Transportation (Caltrans) has developed vibration criteria based on human perception and structural damage risks. For most structures, Caltrans considers Yuba County 10 January 11, 2007

13 a peak particle velocity (ppv) threshold of 0.2 inches per second (in/sec) to be the level at which architectural damage (i.e., minor cracking of plaster walls and ceilings) to normal structures may occur. Below 0.10 in/sec ppv there is virtually no risk of architectural damage to normal buildings. Levels above 0.4 in/sec ppv may possibly cause structural damage (Caltrans, 2002). In terms of human annoyance, continuous vibrations in excess of 0.1 in/sec ppv are identified by Caltrans as the minimum perceptible level for ground vibration. Short periods of ground vibration in excess of 0.2 in/sec ppv can be expected to result in increased levels of annoyance to people within buildings (Caltrans, 2002). PROJECT IMPACTS AND MITIGATION MEASURES STANDARDS OF SIGNIFICANCE Following Appendix G of the State CEQA Guidelines, noise impacts are considered to be significant if implementation of the project considered would result in any of the following: 1. Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance or of applicable standards of other agencies. 2. Exposure of persons to or generation of excessive groundborne vibration or groundborne noise levels. 3. A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project. 4. A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project. 5. For a project located within an airport land use plan area or, where such a plan has not been adopted, within two miles of a public airport or a public use airport, would the project expose people residing or working in the project area to excessive noise levels? 6. For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? Based on the standards of significance in Appendix G of the CEQA Guidelines, the following criteria were used to determine whether implementation of the proposed project would result in a significant noise impact: Short-term Construction Noise Impacts: Short-term construction noise impacts would be considered significant if construction-generated noise would result in a substantial increase in ambient noise levels at noise-sensitive receptors during the more noise-sensitive early morning, evening and nighttime hours (i.e., 7:00 p.m. to 7:00 a.m. ) Long-term Traffic Noise Impacts: Long-term traffic noise impacts would be considered significant if the proposed project would contribute to a substantial increase in predicted traffic noise levels that would exceed the normally acceptable noise standards for land use compatibility at Yuba County 11 January 11, 2007

14 nearby noise-sensitive land uses (Table 3). For purposes of this analysis and in accordance with generally recognized noise standards, increases in predicted traffic noise levels of 5 dba, or greater, would be considered significant in areas where the ambient noise environment is less than 60 dba. In areas where the ambient noise environment is between 60 and 65 dba, increases of 3.0 dba, or greater, would be considered significant. In areas where the ambient noise environment equals or exceeds 65 dba, a predicted increase of 1.5 dba, or greater, would be considered significant. For areas equal to or greater than 70 dba, increases of greater than 1 dba would be considered significant. These thresholds were initially recommended by the Federal Interagency Committee on Noise (FICON) in 1972, based on noise levels at which people typically become increasingly annoyed. These recommendations have since been recognized by various local, state and federal agencies and are typically used for the analysis of transportation noise impacts (FAA, 2000). Long-term Stationary-Source Noise Impacts: Long-term stationary-source noise impacts would be considered significant if predicted noise levels at nearby existing or proposed noise-sensitive land uses would exceed County s noise standards (Table 4). Exposure of Sensitive Receptors or Generation of Excessive Vibration Levels: Short- and long-term vibration impacts would be significant if construction or operation of the proposed project would result in the exposure of sensitive receptors to or generate excessive vibration levels. Ground-borne vibration impacts will be analyzed in comparison to Caltrans-recommended criteria for structural damage and human annoyance. Caltrans considers a peak particle velocity (ppv) threshold of 0.2 inches per second to be the level at which architectural damage (i.e., minor cracking of plaster walls and ceilings) to normally-constructed buildings may occur. Short periods of ground vibration in excess of 0.2 inches per second can be expected to result in increased levels of annoyance to people within buildings (Caltrans 1996, 2002). PROJECT IMPACTS AND MITIGATION MEASURES Impact 1 Exposure to Short-term Construction Noise. Short-term construction-generated noise levels could result in a substantial increase in ambient noise levels at nearby sensitive land uses that are constructed and inhabited before other portions of the project are complete. This would be a significant impact. Construction noise in any one particular area would be temporary and would include noise from activities such as excavations, site preparation, truck hauling of material, pouring of concrete, and use of power hand tools. Construction noise typically occurs intermittently and varies depending on the nature of the construction activities being performed. Noise generated by construction equipment, including excavation equipment, material handlers, and portable generators, can reach high levels for brief periods. When noise levels generated by construction operations are being evaluated, activities occurring during the more noise-sensitive evening and nighttime hours are of increased concern. Because exterior ambient noise levels typically decrease during the late evening and nighttime hours as community activities (e.g., industrial activities, vehicle traffic) decrease, construction activities performed during these more noise-sensitive periods of the day can result in increased annoyance and potential sleep disruption for occupants of nearby residential dwellings. Yuba County 12 January 11, 2007

15 The United States Environmental Protection Agency (US EPA) has found that the average noise levels associated with construction activities typically range from approximately 76 dba to 84 dba Leq, with intermittent individual equipment noise levels ranging from approximately 75 dba to more than 88 dba for brief periods. Table 6 lists typical uncontrolled noise levels generated by individual pieces of construction equipment at a distance of 50 feet. TABLE 6 TYPICAL CONSTRUCTION EQUIPMENT NOISE LEVELS Equipment Typical Noise Level (dba Lmax) 50 feet from Source Backhoe 80 Compactor 82 Dozer 85 Grader 85 Loader 85 Truck 88 Air Compressor 81 Concrete Mixer 85 Concrete Pump 82 Concrete Vibrator 76 Crane, Mobile 83 Generator 81 Impact Wrench 85 Jack Hammer 88 Paver 89 Pneumatic Tool 85 Pump 76 Roller 74 Saw 76 Sources: Federal Transit Administration 2006 Noise from localized point sources (such as construction sites) typically decreases by approximately 6 dba with each doubling of distance from source to receptor. Given this noise attenuation rate and assuming no noise shielding from either natural or human-made features (e.g., trees, buildings, fences), outdoor receptors within approximately 1,600 feet of construction sites could experience maximum instantaneous noise levels of greater than 60 dba when onsite construction-related noise levels exceed approximately 90 dba at the boundary of the Yuba County 13 January 11, 2007

16 construction site. During development of the proposed project, construction activities occurring during the more noise-sensitive late evening and nighttime hours (i.e., 7 p.m. to 7 a.m.) could result in increased levels of annoyance and potential sleep disruption for occupants of nearby noise-sensitive land uses. As a result, noise-generating construction activities would be considered to have a significant short-term impact. Mitigation Measure MM 1 The following measures shall be implemented: Construction activities (excluding activities that would result in a safety concern to the public or construction workers) shall be limited to between the daytime hours of 7 a.m. and 7 p.m., Monday through Saturday. Construction equipment shall be properly maintained and equipped with noisereduction intake and exhaust mufflers and engine shrouds, in accordance with manufacturers recommendations. Equipment engine shrouds shall be closed during equipment operation. When not in use, motorized construction equipment shall not be left idling. Stationary equipment (e.g., power generators, compressors, etc.) shall be located at the furthest practical distance from nearby noise-sensitive land uses or sufficiently shielded to reduce noise-related impacts. Timing/Implementation: Implemented prior to approval of Tentative Map or Planning Director s Special Permit. Enforcement/Monitoring: Yuba County Community Development Department. With implementation of the above mitigation measure, construction activities would be limited to the daytime hours, excluding activities that would result in a safety concern. Implementation of the proposed mitigation measures, including use of mufflers and shielding of equipment, would reduce construction-generated noise levels by approximately 10 dba (EPA 1971). However, it is unlikely that excessive construction noise would be mitigated to less than significant levels in all circumstances. As a result, this impact would be considered significant and unavoidable. Impact 2 Increases in Long-term Operational Traffic Noise. Implementation of the proposed project would result in substantial increases in traffic noise levels along area roadways. This would be a potentially significant impact. Implementation of the proposed land uses would result in increased traffic volumes on some area roadways. The increase in traffic volumes resulting from implementation of the proposed Yuba County 14 January 11, 2007

17 project would, therefore, contribute to predicted increases in traffic noise levels. The FHWA roadway noise prediction model was used to predict traffic noise levels along affected roadways for existing traffic conditions, with and without implementation of the proposed project. Modeling was conducted for roadways anticipated to be primarily affected by the proposed project, based on predicted traffic volumes obtained from the traffic analysis prepared for this project. The project s contribution to traffic noise levels along area roadways was determined by comparing the predicted noise levels with and without project-generated traffic under existing conditions. Predicted traffic noise levels are summarized in Table 7. As depicted in Table 7, implementation of the proposed project would result in predicted increases in traffic noise levels along primary affected roadways ranging from approximately 2 to 16 dba. Substantial increases in predicted traffic noise levels would largely occur along segments of Feather River Boulevard generally located adjacent to and east of the project site. Substantial increases in predicted noise levels along other area roadways, such as K Way, would be anticipated to occur but would not be predicted to exceed normally acceptable noise levels at nearby receptors. Because implementation of the proposed project would result in a substantial increase in traffic noise levels, this impact would be considered significant. TABLE 7 PREDICTED INCREASES IN TRAFFIC NOISE LEVELS EXISTING CONDITIONS Roadway Segment CNEL (dba) at 50 feet from Near-Travel-Lane Centerline Existing Existing Plus Project Predicted Increase Substantial? Plumas Arboga Rd, West of SR No Feather River Blvd, Algodon Road to A Drive (West) No Feather River Blvd, A Drive (West) to K Way Yes Feather River Blvd, K Way to A Drive (East) Yes Feather River Blvd, A Drive (East) to River Oaks Blvd Yes Feather River Blvd, East of River Oaks Blvd Yes River Oaks Blvd., North of Feather River Blvd No Traffic noise levels were predicted using the FHWA Traffic Noise Model based on data obtained from the traffic analysis prepared for this project. Predicted noise levels do not take into account shielding provided by intervening structures or existing noise barriers. Existing noise-sensitive land uses along Feather River Boulevard, the primarily affected roadway, consist of residential dwellings located east of the project site. These existing residential dwellings are currently shielded from traffic noise from Feather River Boulevard by an approximate 6.5 foot sound wall. Based on the unmitigated noise levels identified in Table 7 and assuming an average noise reduction of 6 dba for the existing barrier, predicted traffic noise levels at these existing residential dwellings would not be anticipated to exceed the Yuba County 15 January 11, 2007

18 conditionally acceptable noise standard of 65 dba CNEL. Nonetheless, these noise-sensitive land uses would still be anticipated to experience a substantial increase in ambient noise levels, particularly at second story locations that are unshielded by existing noise barriers. No additional mitigation measures are available that would reduce this impact to a les than significant level. Therefore, this impact would be considered significant and unavoidable. Impact 3 Exposure of Sensitive Receptors to or Generation of Excessive Stationary- Source Noise Levels. Exposure to noise levels generated by future stationary sources associated with the proposed commercial land uses could result in a substantial increase in ambient noise levels that could exceed the County s noise standards at noise-sensitive land uses. This impact would be potentially significant. Onsite Stationary Noise Sources The proposed project includes a mix of various land uses, including residential, school, commercial and neighborhood parks land uses. These land uses would result in new stationary noise sources that could potentially exceed the County s applicable noise standards at nearby noise-sensitive land uses. Noise levels typically associated with these land uses and associated noise impacts are discussed separately below. Proposed Residential Land Uses Noise from proposed residential dwellings would expose other nearby residences (both existing and project related) to minor increases in ambient noise levels. Noise typically associated with such development includes lawn and garden equipment, voices, and amplified music. Activities associated with these land uses would result in only minor increases in ambient noise levels, primarily during the day and evening hours and less frequently at night, as perceived at the closest residential receptors. Noise levels generated by stationary sources, primarily residential central air conditioning units, averages approximately 60 dba Leq at 3 feet from the source (EPA 1971). Depending on the distance between proposed residential dwellings, noise levels associated with air conditioning units located in side-yard areas could potentially exceed the County s exterior noise standard of 50 dba at neighboring residences. As a result, increased noise levels associated with proposed residential land uses would be considered potentially significant. Proposed Park Facilities The proposed project includes development of an approximately 4.3 acre park, which would be centrally located within the project site. However, the specific uses to be included in the proposed park have not yet been identified. Park uses typically include children s play areas, parking areas, and recreational uses such as ball fields. Noise typically associated with play areas and associated vehicle parking areas include the voices of adults and children and the occasional opening and closing of vehicle doors. However, noises typically associated with such uses, excluding larger recreational uses, are often intermittent and do not typically result in substantial increases in daytime ambient noise levels. The noise-generation potential of onsite recreational uses would be primarily associated with the larger ball fields (i.e., soccer fields, baseball field, basketball courts, etc) used for competitive Yuba County 16 January 11, 2007

19 events. Noise levels associated with smaller recreational uses, such as volleyball courts and basketball courts, do not typically involve large numbers of spectators and, as a result, are typically considered minor sources of noise. Noise generated by larger recreational facilities is primarily associated with the cheering and yelling of spectator crowds. Based on noise measurements conducted for similar projects, average hourly exterior noise levels typically associated with day-use soccer fields, basketball and volleyball courts, typically average less than 60 dba Leq at approximately 50 feet, with maximum intermittent noise levels of up to approximately 90 dba Lmax at 10 feet. Events involving the use of amplified sound systems can generate noise levels of approximately 75 dba Leq at 50 feet. Recreational uses involving use of amplified sound systems or activities occurring during the more noise-sensitive evening, nighttime, and early morning hours may result in substantial increases in ambient noise levels at nearby existing or proposed residences, resulting in potential increases in annoyance and sleep disruption. As a result, this impact is considered potentially significant. Proposed Onsite Commercial Uses The proposed project includes development of approximately 17.8 acres of commercial land uses near the southeastern portion of the project site. However, the specific types of commercial uses to be developed have not yet been determined. Potential sources of noise associated with these types of land uses can vary substantially. Noise sources commonly associated with such uses can include occasional parking lot activities (e.g., opening and closing of vehicle doors, people talking), loading dock operations (e.g., use of forklifts, hydraulic lifts), trash compactors, and air compressors. Noise commonly associated with commercial land uses, such as idling trucks, vehicle backup alarms, decompression of trailer truck brakes, forklifts, and other material loading and unloading activities, can generate intermittent noise levels of approximately 90 dba Lmax at 10 feet. Average-hourly noise levels associated with commercial sources typically range from approximately dba Leq at 50 feet. The nearest noise-sensitive land uses in the vicinity of proposed onsite commercial land uses would include proposed residential dwellings located adjacent to the northern, eastern, and western boundaries of the parcel. Based on the maximum noise levels identified above and assuming that the proposed commercial uses were to include loading dock facilities, predicted average-hourly noise levels could potentially exceed 66 dba Leq at adjacent land uses. Intermittent noise levels could potentially exceed 90 dba Lmax at these same receptors. Predicted operational noise levels associated with the proposed commercial land uses could exceed the County s noise standard of 50 dba Leq. In addition, activities occurring during the more noise-sensitive nighttime hours may also result in increased levels of annoyance and potential sleep disruption to occupants of nearby residential dwellings. For these reasons, noise generated by the proposed commercial land uses would be considered potentially significant. Proposed Elementary School Noise sources typical of schools include the sound of children s voices during recess periods and play area activities, mechanical building equipment (e.g., heating, ventilation, and air conditioning systems, and boilers), landscape maintenance equipment, and exterior intercom/speaker systems. Noise generated by landscape maintenance activities conducted at the proposed elementary school, particularly if activities occur during the more noise-sensitive Yuba County 17 January 11, 2007

20 evening or early morning hours, may also result in a significant impact to nearby planned residential dwellings. The hours of operation for the proposed school would typically be limited to the daytime hours, with the potential for after-school and weekend play area activities. School-sponsored events at schools do not typically involve outdoor activities during the nighttime hours. In addition, school activities such as band, athletic, and entertainment events are exempt from the applicable noise standards. Mechanical building equipment (e.g., heating, ventilation, and air conditioning systems, and boilers) associated with the proposed school could generate noise levels of approximately 90 dba at 3 feet from the source. However, such mechanical equipment systems are typically shielded from direct public exposure and usually housed on rooftops, within equipment rooms, or within exterior enclosures (U.S. Environmental Protection Agency 1971). As a result, noise generated by onsite mechanical equipment would not be anticipated to result in a substantial increase in ambient noise levels at nearby land uses. Landscape maintenance equipment, such as leaf blowers and gasoline-powered lawn mowers, associated with the proposed school could result in intermittent noise levels that range from approximately 80 to 120 dba Lmax at 3 feet, respectively. Landscape maintenance activities would be intermittent and are typically limited to daytime hours of operation. However, landscape maintenance activities occurring during the more noisesensitive evening and nighttime hours could result in increased levels of annoyance and potential sleep disruption to occupants of nearby existing and proposed residential land uses. As a result, noise associated with the proposed schools would be considered potentially significant. Proposed Water Treatment Plant and Well Stations The proposed project includes construction of a water treatment plant near the southeastern boundary of the project site, as well as three pump stations located within the boundaries of the project site. Operation of the proposed facilities could result in an increase in ambient noise levels at nearby noise-sensitive land uses. The potential increases would depend on the design and location of stationary noise-generating equipment. Noise-producing equipment typically associated with these types of facilities includes electrical pump motors, transformers, and emergency use power generators. Depending on the type and size of the pumps required, operational noise levels can range from approximately 65 to 90 dba at 10 feet. However, larger pumps often used at water well stations are often located below the ground surface, which substantially reduces detectable operational noise levels at the surface. Electrical generators and transformers can generate noise levels of approximately 80 dba at 3 feet (U.S. EPA, 1971). Additional equipment, such as water filtration and chlorination systems typically generate noise levels of approximately 58 dba, or less, at 3 feet. The proposed onsite water treatment plant and well stations would be similar in design and size of the existing water treatment facility located along Algodon Road and existing well stations currently located within the development located north of the project site. Based on noise measurements conducted at these and other similar facilities, combined operational noise levels from onsite equipment at water treatment plants (excluding emergency-use power generators) typically range from approximately 45 to 60 dba Leq at 50 feet, depending on the equipment being operated. Normal operational noise levels at well stations (excluding the operation of emergency-use power generators) generally range from approximately dba Leq at a distance of approximately 15 feet. Assuming that the proposed water treatment and well station facilities would be equipped with backup electrical power generators, maximum hourlyaverage noise levels could reach levels of approximately 90 dba Leq at 10 feet. Operation of the emergency stand-by generator would occur on an intermittent, as-needed basis during power outages and routine maintenance operations. However, these facilities and related Yuba County 18 January 11, 2007

21 operational characteristics have not been sufficiently defined at this time to accurately assess related noise impacts to nearby noise-sensitive receptors. Therefore, stationary source noise impacts associated with the proposed facilities are considered to have a potentially significant impact. Offsite Stationary Noise Sources Dana & Dana Fruit Processing Facility The Dana & Dana Inc. fruit processing facility is located approximately 275 feet west of the project site (refer to Exhibit 2). Activities conducted at this facility include prune drying and walnut hulling and drying. The facility typically operates approximately twelve hours a day, between the daytime hours of 6 a.m. and 6 p.m. Peak operational periods generally occur three months per year, during the months of August through October. Noise sources at this facility are primarily associated with the onsite operation of motorized equipment (i.e., forklifts, tractors, and haul trucks) and material loading and unloading activities. During peak operational months (i.e., August through October) the facility averages approximately 12 trucks per day. Stationary equipment, including the hulling machine and fan motors used for dryers, are located within enclosed buildings and/or shielded from direct line-of-sight to the proposed project site (pers. com., Dana 2007). Based on noise surveys conducted for this project, onsite stationary processing equipment was detectable at the western boundary of the project site, but was not found to contribute substantially to overall noise generated by this facility, as perceived at the western boundary of the project site. Measured noise levels from this facility were largely influenced by the onsite operation of motorized vehicles and equipment, as noted above. Noise from such sources is often sporadic and varies depending on the specific type of equipment used. Noise levels generated by larger equipment, including forklifts, haul trucks, and tractors, can reach intermittent levels of approximately 80 dba at 50 feet for brief periods of time. As a result, onsite operational noise levels would likely be greatest in areas where multiple pieces of equipment would be used for the loading and unloading of materials. Combined average-hourly noise levels associated with the idling of trucks and the loading and unloading of materials typically average approximately dba Leq at 50 feet. Proposed onsite sensitive land uses located in the vicinity of the fruit processing facility include residential dwellings, the nearest of which are located approximately 350 feet east of the facility. Assuming a maximum average-hourly noise level of 65 dba Leq at 50 feet, predicted averagehourly noise levels at the nearest proposed onsite residential land use would be approximately 48 dba Leq. This predicted maximum hourly-average noise level is generally consistent with the measured ambient noise levels obtained at the western boundary of the project site. As noted earlier in this report, average-hourly daytime noise levels measured along the western boundary of the project site, in the vicinity of the fruit processing plant, ranged from a low of approximately 39 dba Leq during the month of January to a high of approximately 46 dba Leq during the month of October. Based on these predicted and measured noise levels, operational noise levels from the fruit processing facility would not be anticipated to exceed the County s noise standards of 50 dba Leq at onsite receptors. In addition, given that operational hours of the facility are largely limited to the daytime hours, operational activities at the facility would not be anticipated to result in increased levels of annoyance or sleep disruption to occupants of nearby proposed residential dwelling units. Therefore, exposure of proposed onsite noise-sensitive land uses to noise from the existing fruit processing facility would be considered less than significant. Yuba County 19 January 11, 2007