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TABLE 3.7-1. EXISTING NOISE LEVELS AT THE PROJECT SITE
<br />(a) Locations are keyed to monitoring sites shown in Figure 3.7-1.
<br />(b) Peak hour derived by adding 1 dBA.
<br />(c) Calculated level (peak hour Leq (dBA) + 2 dBA = approximate Ldn).
<br />Source: Earth Metrics Incorporated, 1987.
<br />The existing 53 dBA Ldn sound level measured at Location 1 is below the 65 dBA
<br />Ldn limit which is designated by the Zoning Ordinance for residential areas.
<br />Locations 2 and 3 were measured to be above the Zoning Ordinance limit and
<br />were measured to be 70 dBA Ldn and 67 dBA Ldn, respectively. At Location 2,
<br />the high sound level was due to noise from trucks entering and exiting Tracy
<br />Defense Depot and gravel trucks traveling to and from nearby gravel pits. The
<br />sound level at Location 3 was also influenced by gravel trucks. In general,
<br />heavy trucks, like those used by the nearby gravel excavating companies,
<br />generate noise between 70 and 90 dBA at a distance of 50 feet when fully
<br />loaded. At the time of the measurements, railroad noise was not experienced.
<br />However, based on the noise study conducted for the San Joaquin County Council
<br />of Governments, a noise level of 65 dBA is estimated to occur approximately
<br />206 feet from the center of the railroad track (San Joaquin County Council of
<br />Governments).
<br />IMPACTS. Initial noise impacts of the proposed project would result from
<br />construction operations. Project generated motor vehicle noise increases
<br />would follow with completion and occupancy of the project. The completed
<br />project also would be subject to noise impacts from increased traffic levels
<br />in the project area.
<br />Construction Noise. Increases in noise levels during the construction
<br />activities would occur as a result of direct construction noise in the
<br />construction area, and construction truck traffic along the haul routes. The
<br />direct construction noise on site would result from construction operations.
<br />The construction equipment identified as major sources of noise and typical
<br />sound levels (dBA) of this equipment at 50 feet are: dump trucks (88),
<br />portable air compressors (81), concrete mixer (truck) (85), jackhammer (88),
<br />scraper (88), bulldozer (87), paver (89), generator (76), piledriver (101),
<br />rock drill (98), pumps (76), pneumatic tools (85), and backhoes (85) (EPA,
<br />1971).
<br />3.7-3
<br />PEAK
<br />HOUR
<br />LOCATION
<br />DISTANCE FROM CENTER
<br />Leq
<br />Ldn
<br />(a)
<br />TIME
<br />OF NEAREST LANE
<br />Leq(dBA)
<br />(dBA)(b)
<br />(dBA)(c,
<br />1
<br />1:11 - 1:31
<br />P.M. 31 feet
<br />50
<br />51
<br />53
<br />2
<br />1:44 - 2:04
<br />P.M. 33 feet
<br />67
<br />68
<br />70
<br />3
<br />2:20 - 2:40
<br />P.M. 31 feet
<br />64
<br />65
<br />67
<br />(a) Locations are keyed to monitoring sites shown in Figure 3.7-1.
<br />(b) Peak hour derived by adding 1 dBA.
<br />(c) Calculated level (peak hour Leq (dBA) + 2 dBA = approximate Ldn).
<br />Source: Earth Metrics Incorporated, 1987.
<br />The existing 53 dBA Ldn sound level measured at Location 1 is below the 65 dBA
<br />Ldn limit which is designated by the Zoning Ordinance for residential areas.
<br />Locations 2 and 3 were measured to be above the Zoning Ordinance limit and
<br />were measured to be 70 dBA Ldn and 67 dBA Ldn, respectively. At Location 2,
<br />the high sound level was due to noise from trucks entering and exiting Tracy
<br />Defense Depot and gravel trucks traveling to and from nearby gravel pits. The
<br />sound level at Location 3 was also influenced by gravel trucks. In general,
<br />heavy trucks, like those used by the nearby gravel excavating companies,
<br />generate noise between 70 and 90 dBA at a distance of 50 feet when fully
<br />loaded. At the time of the measurements, railroad noise was not experienced.
<br />However, based on the noise study conducted for the San Joaquin County Council
<br />of Governments, a noise level of 65 dBA is estimated to occur approximately
<br />206 feet from the center of the railroad track (San Joaquin County Council of
<br />Governments).
<br />IMPACTS. Initial noise impacts of the proposed project would result from
<br />construction operations. Project generated motor vehicle noise increases
<br />would follow with completion and occupancy of the project. The completed
<br />project also would be subject to noise impacts from increased traffic levels
<br />in the project area.
<br />Construction Noise. Increases in noise levels during the construction
<br />activities would occur as a result of direct construction noise in the
<br />construction area, and construction truck traffic along the haul routes. The
<br />direct construction noise on site would result from construction operations.
<br />The construction equipment identified as major sources of noise and typical
<br />sound levels (dBA) of this equipment at 50 feet are: dump trucks (88),
<br />portable air compressors (81), concrete mixer (truck) (85), jackhammer (88),
<br />scraper (88), bulldozer (87), paver (89), generator (76), piledriver (101),
<br />rock drill (98), pumps (76), pneumatic tools (85), and backhoes (85) (EPA,
<br />1971).
<br />3.7-3
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