Draft EIS for Divert Activities and Exercises 1 3. Affected Environment 2 Throughout the EIS, the affected environment on both Saipan and Tinian will be referred to as the 3 “Project Area.” The term “Project Area” encompasses those locations described under Alternative 1 and 4 Alterative 2 in Sections 2.3.1 and 2.3.2, respectively. Specifically, the Project Area on both Saipan and 5 Tinian includes the airport and associated infrastructure proposed for construction or improvements, and 6 the surrounding area, when applicable. The Project Area also includes locations at the harbor proposed 7 for construction or improvements, and the proposed fuel truck routes and surrounding areas, as depicted 8 in Figures 2.3-1 and 2.3-11. 9 3.1 Noise 10 3.1.1 Definition of Resource 11 Sound is defined as a particular auditory effect produced by a given source, for example the sound of rain 12 on a rooftop. Noise and sound share the same physical aspects, but noise is considered a disturbance 13 while sound is defined as an auditory effect. Noise is defined as any sound that is undesirable because it 14 interferes with communication, is intense enough to damage hearing, or is otherwise annoying. Noise can 15 be intermittent or continuous, steady or impulsive, and can involve any number of sources and 16 frequencies. It can be readily identifiable or generally nondescript. Human response to increased sound 17 levels varies according to the source type, characteristics of the sound source, distance between source 18 and receptor, receptor sensitivity, and time of day. How an individual responds to the sound source will 19 determine if the sound is viewed as music to one’s ears or as annoying noise. Affected receptors are 20 specific (e.g., schools, churches, or hospitals) or broad (e.g., nature preserves or designated districts) areas 21 in which occasional or persistent sensitivity to noise above ambient levels exists. 22 Noise Metrics and Regulations. Although human response to noise varies, measurements can be 23 calculated with instruments that record instantaneous sound levels in decibels. A-weighted decibel (dBA) 24 is used to characterize sound levels that can be sensed by the human ear. “A-weighted” denotes the 25 adjustment of the frequency range to what the average human ear can sense when experiencing an audible 26 event. The threshold of audibility is generally within the range of 10 to 25 dBA for normal hearing. The 27 threshold of pain occurs at the upper boundary of audibility, which is normally in the region of 135 dBA 28 (USEPA 1981b). Table 3.1-1 compares common sounds and shows how they rank in terms of the effects 29 of hearing. As shown, a whisper is normally 30 dBA and considered to be very quiet while an air 30 conditioning unit 20 feet away is considered an intrusive noise at 60 dBA. Noise levels can become 31 annoying at 80 dBA and very annoying at 90 dBA. To the human ear, each 10 dBA increase seems twice 32 as loud (USEPA 1981a). 33 Under the Noise Control Act of 1972, the Occupational Safety and Health Administration (OSHA) 34 established workplace standards for noise. The minimum requirement states that constant noise exposure 35 must not exceed 90 dBA over an 8-hour period. The highest allowable sound level to which workers can 36 be constantly exposed to 115 dBA and exposure to this level must not exceed 15 minutes within an 37 8-hour period. The standards limit instantaneous exposure, such as impact noise, to 140 dBA. If noise 38 levels exceed these standards, employers are required to provide hearing protection equipment that will 39 reduce sound levels to acceptable limits. 40 Sound levels, resulting from multiple single events, are used to characterize noise effects from aircraft or 41 vehicle activity and are measured in Day-Night Average Sound Level (DNL). The DNL noise metric 42 incorporates a “penalty” for nighttime noise events to account for increased annoyance. DNL is the HQ PACAF, Joint Base Pearl Harbor-Hickam, HI June 2012 3-1 Draft EIS for Divert Activities and Exercises 1 Table 3.1-1. Sound Levels and Human Response Noise Level Common Sounds Effect (dBA) 10 Just audible Negligible* 30 Soft whisper (15 feet) Very quiet 50 Light auto traffic (100 feet) Quiet 60 Air conditioning unit (20 feet) Intrusive 70 Noisy restaurant or freeway traffic Telephone use difficult 80 Alarm clock (2 feet) Annoying Very annoying 90 Heavy truck (50 feet) or city traffic Hearing damage (8 hours) 100 Garbage truck Very annoying* 110 Pile drivers Strained vocal effort* 120 Jet takeoff (200 feet) or auto horn (3 feet) Maximum vocal effort 140 Carrier deck jet operation Painfully loud Source: USEPA 1981a and *HDR extrapolation 2 energy-averaged sound level measured over a 24-hour period, with a 10-dBA penalty assigned to noise 3 events occurring between 10:00 p.m. and 7:00 a.m. DNL values are obtained by averaging sound 4 exposure levels over a given 24-hour period. DNL is the designated noise metric of the FAA, 5 U.S. Department of Housing and Urban Development (HUD), USEPA, and DOD for modeling airport 6 environments. 7 According to the USAF, the FAA, and the HUD criteria, residential units and other noise-sensitive land 8 uses within or above the 65 dBA DNL contour are considered to be within areas of high noise exposure. 9 The Federal Interagency Committee on Noise developed land use compatibility guidelines for noise in 10 terms of a DNL sound level (FICON 1992). For outdoor activities, the USEPA recommends 55 dBA 11 DNL as the sound level below which there is no reason to suspect that the general population would be at 12 risk from any of the effects of noise (1974). 13 Aircraft Sound Levels. For this analysis, the NOISEMAP noise modeling program was used. 14 NOISEMAP is a DOD-approved computer modeling program used to define noise levels in areas near 15 USAF installations. An analysis of existing and proposed conditions was estimated from the flying 16 operations including types of aircraft, flight patterns, variations in altitude, power settings, number of 17 operations, and hours of operation. This information was used to develop the noise contours contained in 18 this document. 19 Ambient Sound Levels. Noise levels vary depending on the housing density and proximity to parks and 20 open space, major traffic areas, or airports. As shown on Table 3.1-2, the noise level in a normal 21 suburban area is about 55 dBA DNL, which increases to 60 dBA for an urban residential area, and to 22 80 dBA in the downtown section of a city (USEPA 1974). Most people are exposed to sound levels of 23 50 to 55 dBA or higher on a daily basis. 24 Construction Sound Levels. Building demolition and construction work can cause an increase in sound 25 that is well above the ambient level. A variety of sounds are emitted from loaders, trucks, pavers, and 26 other work equipment. Table 3.1-3 lists noise levels associated with common types of construction 27 equipment. Construction equipment usually exceeds the ambient sound levels by 20 to 25 dBA in an 28 urban environment and up to 30 to 35 dBA in a quiet suburban area. HQ PACAF, Joint Base Pearl Harbor-Hickam, HI June 2012 3-2 Draft EIS for Divert Activities and Exercises 1 Table 3.1-2. Typical Outdoor Noise Levels dBA DNL Location 50 Residential area in a small town or quiet suburban area 55 Suburban residential area 60 Urban residential area 65 Noisy urban residential area 70 Very noisy urban residential area 80 City noise (downtown of major metropolitan area) 88 3rd floor apartment in a major city next to a freeway Source: USEPA 1974 2 Table 3.1-3. Predicted Noise Levels for Construction Equipment Construction Predicted Noise Level Equipment at 50 feet (dBA) Backhoe 72–93 Concrete mixer 74–88 Crane 75–87 Front loader 72–83 Grader 80–93 Jackhammer 81–98 Paver 86–88 Pile driver 95–105 Roller 73–75 Truck 83–94 Source: USEPA 1971 3 3.1.2 Existing Conditions 4 The noise analysis contained in the Draft EIS is based upon readily available background information and 5 data that were current at the time of the analysis. Refinement of the noise analysis is an ongoing process 6 and will be finalized based on Draft EIS comments prior to the Final EIS. 7 3.1.2.1 Alternative 1 – GSN 8 The area around GSN is mainly rural; however, there are a few major noise sources. These sources 9 include vehicle traffic, an adjacent quarry, and aircraft operations. Major roadways adjacent to GSN 10 include Flame Tree Road, Airport Road, As Perdido Road, and Naftan Road. However, the dominant 11 sources of noise come from quarry and airport operations. Hawaiian Rock Quarry is approximately 12 0.75 miles southeast of the runway and 1 mile south of Dandan. This company supplies asphalt, concrete, 13 and aggregates. The facility near GSN includes a quarry and main concrete plant. HQ PACAF, Joint Base Pearl Harbor-Hickam, HI June 2012 3-3 Draft EIS for Divert Activities and Exercises 1 Annual aircraft operations for the Baseline Scenario were obtained from FAA Air Traffic Activity System 2 database (FAA 2011). Daily operations at GSN are shown in Table 3.1-4. An operation is defined as an 3 aircraft arrival or an aircraft departure; therefore, the landing and takeoff of the same aircraft would count 4 as two operations.