Construction Noise Memorandum To: Ms. Paula Daneluk Date: June 13, 2013 Development Impact 9370 Studio Court, Suite 160 Elk Grove, CA 95758 From: Paul Bollard Bollard Acoustical Consultants, Inc. 3551 Bankhead Road Loomis, CA 95650 Subject: Sutter Creek (Amador County), California Pursuant to your request, Bollard Acoustical Consultants, Inc. (BAC) has assessed potential construction noise-related impacts for the (project). This analysis was conducted to ensure that the construction related noise levels do not exceed the applicable Caltrans and Sutter Creek noise standards. Project Description The City of Sutter Creek proposes to replace the Badger Street Bridge in the City of Sutter Creek. The existing bridge carries Badger Street over Sutter Creek and the proposed project is immediately south of Spanish Street. The project area is shown in Attachment A. Existing Bridge Construction The existing Badger Street Bridge is a continuous five span structure with a flat slab on reinforced concrete pier walls and abutments. The bridge was constructed in 1960 and is currently classified as structurally deficient. The existing bridge is two lanes wide and is configured as a local road. Badger Street is a conventional two-lane, undivided local roadway with two 12-foot lanes, flanked by a drainage swale on the west side. The existing structure is constructed on sand and gravel. The abutments are constructed of reinforced concrete. The bridge has five spans supported by three sets of piers made up of reinforced concrete located on reinforced concrete spread footings. Five holes have been cored in the existing deck of span 2. It appears the holes were to allow the deck to drain. The cores have created large spalls (0.3 m in diameter) in the soffit and have exposed a few reinforcing bars which are covered with surface rust. Six millimeter wide cracks are located in both exterior faces of the abutment diaphragms and also have some exposed reinforcing bars. 3551 Bankhead Road Loomis, CA 95650 Phone: (916) 663-0500 Fax: (916) 663-0501 BACNOISE.COM
Development Impact June 13, 2013 Page 2 The bridge, located in a residential area of Sutter Creek, provides for vehicular and pedestrian access, although there are no designated sidewalks. The creek is free flowing beneath the structure and is primarily sand and gravel in the vicinity of the bridge with some larger rocks downstream from the structure. Currently the bridge is inundated during storm events and overtops by up to six feet during a 100 year flood. Proposed Bridge Construction The existing bridge would be removed and replaced with a raised bridge and roadway profile at crossing of Sutter Creek. The lower five-span bridge would be replaced with a higher profile two-span bridge capable of passing 100-year flood flows without overtopping. The bridge would have two 10 foot lanes with two 3 foot shoulders and one 6 foot sidewalk. The sewer line on the north end of the bridge would be relocated as part of the project to be located behind the proposed abutment. The existing sewer manhole on the south end of the bridge would be raised to meet the proposed grade. The grade of the existing Badger Street roadway would be raised with fill to tie-in with the raised bridge. The tie-in is proposed to extend approximately 100 feet to the north and south of the proposed bridge. Roadway work and new fill on the west side of Badger Street, north of the bridge will require the existing drainage swale between Spanish Street and the bridge would be piped. The proposed bridge alignment elevation profile is illustrated in Attachment B. The proposed bridge would be approximately seventy (70) feet in length. Including barriers and railings, the resulting bridge width is thirty-six (36) feet. Approach roadways would be rehabilitated after the new bridge is placed and utilities are reconnected. Rehabilitation of the approaches would consist of re-paving the road and restriping. At the bridge deck, improvements would include construction of shoulders and traffic barriers, railing, sidewalk, and curb ramps. Equipment staging would be located on the existing roadway or on adjacent open private property through the use of a temporary construction easement. The road within the project area would be fully closed during the project construction and detour routes would be made available to maintain access to all residential properties affected by the closure. Preliminary design indicates permanent right-of-way acquisition would not be required; however, temporary construction easements and utility relocations (without right-of-way acquisition) would be necessary.
Development Impact June 13, 2013 Page 3 Criteria for Acceptable Noise Exposure Municipal Code of the City of Sutter Creek Chapter 10.50, Noise Regulations, of the City s municipal code provides policies to prohibit unnecessary, excessive and annoying noises from various sources. Section 10.50.120, Building and Construction Noise Limitations, limits the hours of operations for constructionrelated activities. The section states: It is unlawful for any person within a residential zone, or within a radius of five hundred feet, to operate equipment or perform any outside construction or repair work on buildings, structures or projects or to operate any pile driver, power shovel, pneumatic hammer, derrick, power hoist or any other construction-type device, between the hours of 7:00 p.m. of one day and 7:00 a.m. of the next day, in such a manner that a reasonable person of normal sensitiveness residing in the area is caused discomfort or annoyance unless, beforehand, a permit has been duly obtained from the planning commission. Caltrans Standard Specifications (2010) Section 14-8.02, Noise Control, of Caltrans standard specifications provides information that can be considered in determining whether construction would result in adverse noise impacts. The specification states: Do not exceed 86 dba at 50 feet from the job site activities from 9 p.m. to 6 a.m. Equip an internal combustion engine with the manufacturer-recommended muffler. Do not operate an internal combustion engine on the job site without the appropriate muffler. Existing Ambient Conditions The noise environment in the project vicinity is primarily defined by traffic noise emanating from Badger Street. To quantify existing ambient noise levels at the nearest residences to the proposed construction area, BAC conducted a short-term noise survey at two locations shown on Attachment A on the morning of September 26, 2012. BAC also conducted a long-term noise survey on September 22-25, 2012. Larson-Davis Laboratories (LDL) 820 precision integrating sound level meters were used to complete the noise level measurement surveys. The meters were calibrated before use with a LDL Model CAL200 calibrator to ensure the accuracy of the measurements. The equipment used meets all pertinent specifications of the American National Standards Institute for Type 1 sound level meters (ANSI S1.4). The noise level measurement results are summarized below in Table 1 and 2. The measurement results indicate that ambient conditions in the immediate project vicinity are typical for semi-rural areas affected by local roadway noise.
Development Impact June 13, 2013 Page 4 Location* Table 1 Summary of Short-Term Ambient Noise Measurement Results September 26, 2012 Time Measured Noise Levels (dba) L eq L 50 L 90 L max ST1 10:36 AM 51 38 33 69 ST2 10:56 AM 52 37 33 76 Notes: * See Attachment A for noise measurement locations. Source: Bollard Acoustical Consultants, Inc. Table 2 Summary of Long-Term Ambient Noise Measurement Results A September 22-25, 2012 Measured Noise Levels (dba) B Daytime (7 AM 10 PM) Nighttime (10 PM 7 AM) Day L eq L 50 L 90 L max L eq L 50 L 90 L max 9/22/12 50 40 36 75 40 37 34 64 50 9/23/12 47 39 36 79 39 38 36 64 48 9/24/12 53 41 36 89 41 36 33 73 52 9/25/12 47 39 35 80 37 56 30 68 47 A Notes: See Attachment A for noise measurement locations. B Detailed noise measurement results (hour by hour chart and graph) are provided as Attachments C & D. Source: Bollard Acoustical Consultants, Inc. L dn Evaluation of Construction Noise Generation The Federal Highway Administration (FHWA) Roadway Construction Noise Model (RCNM) was utilized to model the various project equipment noise levels at the nearest noisesensitive locations. For modeling purposes, the project operations were divided into three separate construction phases. Phase 1 represents construction activities that typically take place during the start of construction. Phase 2 represents construction activities that typically take place during the middle of construction. Phase 3 represents construction activities that typically take place towards the end of construction. The phase dependant project equipment modeling assumptions can be seen in Table 3. The RCNM results are provided in Table 4.
Development Impact June 13, 2013 Page 5 Table 3 Assumed Construction Equipment Operations During Various Project Phases Construction Equipment Phase 1 Phase 2 Phase 3 Backhoe X Dozer X Grader X Scraper X Compactor (ground) X Concrete Mixer Truck X Paver X Pickup Truck 1 X X X Pickup Truck 2 X X X Source: Bollard Acoustical Consultants, Inc. Receiver ID A Table 4 Summary of Predicted Construction Equipment Noise Levels Land Use Distance (feet) B Predicted Noise Levels (dba) Phase 1 Phase 2 Phase 3 L eq L max L eq L max L eq L max R1 Residential 40 85 86 85 87 82 85 R2 Residential 85 78 79 78 80 75 79 R3 Residential 165 73 73 72 75 69 73 R4 Residential 40 85 86 85 87 82 85 R5 Residential 50 83 84 83 85 80 83 R6 Residential 40 85 86 85 87 82 85 A Notes: See Attachment A for receiver locations. B Approximate distances to construction activities. Source: Bollard Acoustical Consultants, Inc. As noted previously, the project proposes to increase the elevation of the Badger Street Bridge to accommodate 100-year flood flows. The increase in bridge elevation will be approximately 3 feet at the north end of the bridge span, and approximately 7 feet at the south end of the span. In front of the nearest residence to the bridge reconstruction (Receptor 4 located approximately 75 feet south of the existing bridge span), the change in roadway elevation would be approximately 1 foot. Relative to the horizontal distances between the nearest residences and the reconstructed bridge/roadway, the increase in vertical elevation of the bridge structure is small. BAC computed the change in straight line distance from nearest residences to the roadway after bridge reconstruction as being within one (1) foot of the existing straight-line distance.
Development Impact June 13, 2013 Page 6 This subtle decrease in distance between the nearest residences and the roadway resulting from the increased height of the new bridge would translate to a noise level increase of less than 0.2 db. Because such an increase is below the threshold of perception, and because the change in bridge elevation would not appreciably affect existing topographic shielding of roadway noise levels at the nearest residences, the proposed modification to the vertical alignment of the bridge would not result in adverse noise impacts. Analysis of Project Noise Impacts and Required Abatement Measures The Table 4 results indicate that the predicted project construction noise levels would generally be consistent with measured daytime maximum noise levels in the immediate project vicinity. Nonetheless, the Table 4 data indicate that, if nighttime construction activities were to occur for this project, the 86 db Lmax Caltrans specification for nighttime operations could be exceeded. To mitigate this potential impact, and to ensure consistency with the Sutter Creek Municipal Code policy pertaining to construction noise, the following noise abatement measure is recommended: Project construction activities should be limited to the daytime hours of 7 am to 7 pm. Conclusions Although project construction activities would result in short-term periods of elevated ambient noise levels in the immediate project vicinity, provided construction activities are limited to daytime hours (7:00 a.m. 7:00 p.m.), no adverse construction noise impacts are identified for this project. Please contact me at (916) 663-0500 or paulb@bacnoise.com if you have any comments or questions regarding this memorandum. Sincerely, Bollard Acoustical Consultants, Inc. Paul Bollard President Attachments
Attachment C-1 24hr Continuous Noise Monitoring at LT-1 Saturday, September 22, 2012 Hour Leq Lmax L50 L90 Statistical Summary 0:00 36 49 35 34 Daytime (7 a.m. - 10 p.m.) Nighttime (10 p.m. - 7 a.m.) 1:00 35 57 34 33 High Low Average High Low Average 2:00 40 63 38 36 Leq (Average) 58.7 41.8 50.3 43.4 35.4 39.5 3:00 39 48 39 35 Lmax (Maximum) 75.2 58.9 67.6 64.2 46.2 56.3 4:00 38 46 36 32 L50 (Median) 45.4 37.4 40.2 38.8 34.1 36.8 5:00 39 62 36 32 L90 (Background) 40.5 33.4 36.1 37.6 31.5 34.4 6:00 43 64 38 34 7:00 43 74 39 37 Computed Ldn, db 50.0 8:00 42 62 39 37 % Daytime Energy 95% 9:00 54 71 45 34 % Nighttime Energy 5% 10:00 59 73 45 35 11:00 47 70 37 33 12:00 44 63 39 35 13:00 45 69 39 34 14:00 46 70 38 35 15:00 51 75 40 36 16:00 50 65 40 37 17:00 48 71 38 35 18:00 45 69 40 35 19:00 45 59 43 41 20:00 42 61 40 39 21:00 43 62 41 38 22:00 40 57 38 37 23:00 40 61 39 38
Attachment C-2 24hr Continuous Noise Monitoring at LT-1 Sunday, September 23, 2012 Hour Leq Lmax L50 L90 Statistical Summary 0:00 39 56 38 37 Daytime (7 a.m. - 10 p.m.) Nighttime (10 p.m. - 7 a.m.) 1:00 39 56 38 36 High Low Average High Low Average 2:00 37 45 37 36 Leq (Average) 54.4 40.9 47.0 42.3 36.9 39.2 3:00 37 42 37 35 Lmax (Maximum) 78.6 59.5 64.6 64.4 41.9 52.7 4:00 41 64 39 36 L50 (Median) 44.0 35.4 38.7 40.7 36.1 37.7 5:00 39 55 38 35 L90 (Background) 40.2 32.3 35.6 38.0 35.0 36.0 6:00 42 59 41 38 7:00 43 61 41 38 Computed Ldn, db 47.9 8:00 46 65 42 39 % Daytime Energy 91% 9:00 47 64 44 40 % Nighttime Energy 9% 10:00 42 63 36 33 11:00 44 66 38 33 12:00 43 62 37 33 13:00 43 64 39 34 14:00 42 63 37 34 15:00 41 59 39 36 16:00 54 79 38 35 17:00 43 67 36 33 18:00 44 60 35 32 19:00 41 64 39 37 20:00 49 72 39 38 21:00 51 60 40 36 22:00 38 55 36 35 23:00 37 42 37 35
Attachment C-3 24hr Continuous Noise Monitoring at LT-1 Monday, September 24, 2012 Hour Leq Lmax L50 L90 Statistical Summary 0:00 36 49 36 34 Daytime (7 a.m. - 10 p.m.) Nighttime (10 p.m. - 7 a.m.) 1:00 37 47 36 34 High Low Average High Low Average 2:00 37 46 34 32 Leq (Average) 61.0 37.9 52.6 47.8 34.2 40.5 3:00 36 47 35 32 Lmax (Maximum) 88.5 59.5 67.2 73.3 45.6 55.8 4:00 38 58 36 32 L50 (Median) 51.6 35.8 41.4 41.8 31.7 35.8 5:00 40 65 37 34 L90 (Background) 42.1 32.8 36.1 37.8 30.3 33.2 6:00 48 73 42 38 7:00 48 64 44 42 Computed Ldn, db 51.9 8:00 45 61 42 37 % Daytime Energy 96% 9:00 54 69 52 34 % Nighttime Energy 4% 10:00 55 67 50 40 11:00 50 64 46 41 12:00 56 69 43 36 13:00 41 61 37 33 14:00 43 62 37 33 15:00 61 89 40 34 16:00 43 66 38 33 17:00 44 66 38 35 18:00 46 68 38 35 19:00 52 73 43 38 20:00 47 70 38 36 21:00 38 60 36 34 22:00 36 58 34 32 23:00 34 59 32 30
Attachment C-4 24hr Continuous Noise Monitoring at LT-1 Tuesday, September 25, 2012 Hour Leq Lmax L50 L90 Statistical Summary 0:00 33 58 31 29 Daytime (7 a.m. - 10 p.m.) Nighttime (10 p.m. - 7 a.m.) 1:00 30 40 30 29 High Low Average High Low Average 2:00 33 57 28 26 Leq (Average) 51.1 41.8 47.1 41.8 28.8 37.4 3:00 29 49 27 26 Lmax (Maximum) 80.2 62.1 68.9 68.4 39.6 55.7 4:00 30 49 28 26 L50 (Median) 42.1 36.7 38.8 38.8 27.4 32.0 5:00 39 64 34 31 L90 (Background) 39.1 33.3 35.3 34.4 25.6 29.9 6:00 42 63 39 34 7:00 45 63 42 39 Computed Ldn, db 47.2 8:00 45 63 42 39 % Daytime Energy 94% 9:00 46 71 38 35 % Nighttime Energy 6% 10:00 48 80 38 35 11:00 44 64 39 34 12:00 51 77 39 34 13:00 47 74 38 34 14:00 48 78 38 34 15:00 48 70 40 35 16:00 47 67 37 34 17:00 44 65 37 34 18:00 43 62 37 33 19:00 50 71 41 38 20:00 46 63 39 37 21:00 42 65 37 35 22:00 42 68 36 34 23:00 36 54 35 34
Attachment D-1 24hr Continuous Noise Monitoring at LT-1 Saturday, September 22, 2012 Sound Level, dba 90 80 70 60 50 40 30 20 12:00 AM 4:00 AM 8:00 AM 12:00 PM 4:00 PM 8:00 PM 11:00 PM Hour of Day Average (Leq) Maximum (Lmax) L50 L90 Ldn: 50 db
Attachment D-2 24hr Continuous Noise Monitoring at LT-1 Sunday, September 23, 2012 Sound Level, dba 90 80 70 60 50 40 30 20 12:00 AM 4:00 AM 8:00 AM 12:00 PM 4:00 PM 8:00 PM 11:00 PM Hour of Day Average (Leq) Maximum (Lmax) L50 L90 Ldn: 48 db
Attachment D-3 24hr Continuous Noise Monitoring at LT-1 Monday, September 24, 2012 Sound Level, dba 90 80 70 60 50 40 30 20 12:00 AM 4:00 AM 8:00 AM 12:00 PM 4:00 PM 8:00 PM 11:00 PM Hour of Day Average (Leq) Maximum (Lmax) L50 L90 Ldn: 52 db
Attachment D-4 24hr Continuous Noise Monitoring at LT-1 Tuesday, September 25, 2012 Sound Level, dba 90 80 70 60 50 40 30 20 12:00 AM 4:00 AM 8:00 AM 12:00 PM 4:00 PM 8:00 PM 11:00 PM Hour of Day Average (Leq) Maximum (Lmax) L50 L90 Ldn: 47 db