Draft Environmental Impact Report - California Off Highway Vehicle ...

3.3 Noise
equipment. Noise levels from construction and maintenance activities are typically considered a
point source, and drop off at a rate of 6 dBA per doubling of distance over hard site surfaces, such
as streets and parking lots. Noise levels drop off at a rate of approximately 7.5 dBA per doubling of
distance over soft site surfaces, such as grass fields and open terrain with vegetation (FTA 2006:2‐
10 through 2‐11).
Equipment required for construction and maintenance activities at Clay Pit SVRA would include a
paver, backhoe, bulldozer, tractor, and various trucks. The maximum noise levels produced by one
of these types of equipment, at a distance of 50 feet and without the implementation of noise
controls, could range from 80 to 85 dBA Lmax (Table 3.3‐5). Noise levels vary for individual pieces
of equipment because equipment comes in different sizes and with different engines. Noise levels
for construction equipment also vary as a function of the activity level or duty cycle. Typical
construction projects, with equipment moving from one point to another, including work breaks
and idle time, have long‐term noise averages that are lower than many short‐term noise events.
Additionally, noise levels are calculated from the center of the activity because of the dynamic
nature of a construction site. Using these parameters, construction activities, including the
simultaneous operation of multiple pieces of equipment, were modeled to generate a combined
noise level of 86 dBA Leq at 50 feet from the center of construction activity (Appendix D).
TABLE 3.3­5. TYPICAL NOISE LEVELS CAUSED BY CONSTRUCTION EQUIPMENT 1
Equipment Type
Typical Noise Level
(dBA Lmax) at 50 feet
Equipment Type
Typical Noise Level
(dBA Lmax) at 50 feet
Backhoe 80 Generator 82
Concrete mixer truck 85 Grader 85
Concrete pump truck 82 Paver 85
Dozer 85 Tractor 84
Dump truck 84
Notes: dBA = A‐weighted decibels
1 All equipment fitted with properly maintained and operational noise control device, per manufacturer
specifications. Noise levels listed are the actual measured noise levels for each piece of heavy construction
equipment.
Sources: BBN 1981:8‐4 through 8‐5; FTA 2006:12‐6 through 12‐7; FHWA 2006:3
The closest residence along Larkin Road is located approximately 165 feet from the western SVRA
boundary. The intervening ground type is primarily open space and is considered acoustically soft.
Construction and maintenance activities primarily would occur within the Developed Use Area,
located in the northwestern portion of Clay Pit SVRA. When modeled using FTA noise
methodology (FTA 2006:12‐1 through 12‐15) and the above parameters, noise from construction
and maintenance activities would generate a combined noise level of 72 dBA Leq at this residence
along Larkin Road (Appendix D).
Clay Pit State Vehicular Recreation Area
Draft EIR 3.3-21 February 2012