Appendix G Exterior Noise Level Assessment at Common ...

Appendix G

Exterior Noise Level Assessment at Common Outdoor Activity Areas

429 E. Cotati Avenue Cotati, CA 94931

Tel: 707-794-0400 Fax: 707-794-0405 www.illingworthrodkin.com [email protected]

October 20, 2020 Jonathan Emami JEMCOR Development Partners 1700 S El Camino Real, Suite 400 San Mateo, CA 94402 VIA E-Mail: [email protected] SUBJECT: Monterey & Madrone, Morgan Hill, California –

Assessment of Exterior Noise Levels at Common Outdoor Activity Areas Dear Jonathan: This letter summarizes our assessment of exterior noise levels at common outdoor activity areas proposed by the Monterey & Madrone residential project in Morgan Hill, California. The project site is located at the northwest corner of the intersection of Monterey Road and Madrone Parkway and is currently occupied by California Tow & Salvage and Burke’s Upholstery. Figure 1 is the site plan showing the locations of the two common outdoor activity areas proposed by the project; a small open space area proposed near the Amenity Building (Clubhouse), and the patio, tot lot, and open space area proposed on the easternmost portion of the site near Buildings 13 and 14. Regulatory Criteria The Safety, Services and Infrastructure Chapter in the Morgan Hill 2035 General Plan sets forth policies with the goal of minimizing the impact of noise on people through noise reduction and suppression techniques, and through appropriate land use policies in the City of Morgan Hill. The following policies are applicable to the proposed project: Policy SSI-8.1 - Exterior Noise Level Standards. Require new development projects to be designed and constructed to meet acceptable exterior noise level standards (as shown in Table SSI-1) as follows: Apply a maximum exterior noise level of 60 dBA Ldn in residential areas where outdoor use is

a major consideration (e.g., backyards in single-family housing developments and recreation areas in multi-family housing projects). Where the City determines that providing an Ldn of 60 dBA or lower cannot be achieved after the application of reasonable and feasible mitigation, an Ldn of 65 dBA may be permitted.

Indoor noise levels should not exceed an Ldn of 45 dBA in new residential housing units. Noise levels in new residential development exposed to an exterior Ldn 60 dBA or greater

should be limited to a maximum instantaneous noise level (e.g., trucks on busy streets, train warning whistles) in bedrooms of 50 dBA. Maximum instantaneous noise levels in all other

Jonathan Emami October 20, 2020 Page 2

habitable rooms should not exceed 55 dBA. The maximum outdoor noise level for new residences near the railroad shall be 70 dBA Ldn, recognizing that train noise is characterized by relatively few loud events.

Policy SSI-8.9 - Site Planning and Design. Require attention to site planning and design techniques other than sound walls to reduce noise impacts, including: a) installing earth berms, b) increasing the distance between the noise source and the receiver; c) using non-sensitive structures such as parking lots, utility areas, and garages to shield noise-sensitive areas; d) orienting buildings to shield outdoor spaces from the noise source; and e) minimizing the noise at its source.


Policy SSI-9.2 - Noise Barrier Dimensions. If noise barriers are deemed the only effective mitigation for development along major transportation corridors, require an acoustical analysis to determine necessary dimensions. Policy SSI-9.3 - Sound Wall Design. The maximum height of sound walls shall be eight feet. Residential projects adjacent to the freeway shall be designed to minimize sound wall height through location of a frontage road, use of two sound walls or other applicable measures. Sound wall design and location shall be coordinated for an entire project area and shall meet Caltrans noise attenuation criteria for a projected eight-lane freeway condition. If two sound walls are used, the first shall be located immediately adjacent to the freeway right-of-way and the second shall be located as necessary to meet Caltrans noise requirements for primary outdoor areas. The minimum rear yard setback to the second wall shall be 20 feet. Policy SSI-9.4 - Sound Barrier Vandalism. Ensure that sound barriers do not become targets for vandalism and prioritize clean-up if sound walls are vandalized.

Policy SSI-9.6 - Earth Berms. Allow and encourage earth berms in new development projects as an alternative to sound walls if adequate space is available.

Policy SSI-9.7 - Sound Barrier Design. Require non-earthen sound barriers to be landscaped, vegetated, or otherwise designed and/or obscured to improve aesthetics and discourage graffiti and other vandalism. Project Condition of Approval 6 also requires the following:

Sound Walls An Acoustical Analysis shall be provided to demonstrate need for noise impact mitigation. Site planning and design techniques shall be utilized to minimize the use of sound walls. Sound wall is allowed if required to meet noise standards and applicant has demonstrated that other forms of mitigation are not available as described herein. Application demonstrates that other forms of mitigation such as installation of earth berms; increasing the distance between the noise source and the receiver; intervening placement of non-sensitive structures such as parking lots, utility areas, and garages to shield noise sensitive areas; orienting buildings to shield outdoor spaces from the noise sources; and minimizing noise at its source; are not available. If a sound wall is allowed, the maximum height of the sound wall shall be eight feet. Dimension shall be as determined in the acoustical analysis. Residential projects adjacent to the freeway shall meet the criteria as described in SSI-9.3 of the General Plan. The sound wall must be landscaped or vegetated for aesthetic purposes and to prevent graffiti and vandalism. (GP Policy CNF-8.14, SSI-8.9, 9.2, 9.3, 9.4, 9.6, and 9.7.

Existing Noise Environment A noise monitoring survey was conducted between 10:00 am on Monday, October 5th and 9:00 am on Thursday, October 8th, 2020 to quantify the existing noise environment on the project site at


locations representative of proposed residential outdoor activity areas. Vehicle traffic was the predominant noise source affecting the site, with local onsite operations and Union Pacific Railroad (UPRR) operations also contributing to measured noise levels. The noise monitoring survey included one long-term continuous measurements (LT-1 in Figure 1) and one short-term 10-minute duration noise measurement (ST-1 in Figure 1). The noise measurements were made with Larson Davis Laboratories (LDL) Type I Model 820 Sound Level Meters fitted with a ½-inch pre-polarized condenser microphones and windscreens. The meters were calibrated with a Larson Davis Model CAL200 precision acoustic calibrator prior to and following the measurement survey. The long-term noise monitor was positioned at a height of approximately 12 feet above the ground in a tree approximately 205 feet northwest of the centerline of Madrone Parkway. This location was selected to represent the existing noise environment at the primary outdoor activity areas proposed by the project containing a patio, tot lot, and open space. The measured noise levels at this location for Tuesday, October 6th and Wednesday, October 7th are shown in Figures 2 and 3. The Day/Night Average Noise Level (Ldn) was calculated to range from 57 dBA to 58 dBA. On-site operations were likely responsible for the elevated noise levels on the afternoon of October 6th and the morning of October 7th. The attended short-term noise measurement was made between 9:50 and 10:00 am on October 5th, 2020. This measurement was made east of the small open space area proposed near the Clubhouse. Autos along Madrone Parkway produced noise levels ranging from 52 to 64 dBA while trucks produced noise levels ranging from 61 to 63 dBA. Aircraft produced noise levels ranging from 46 to 68 dBA. Table 1 summarizes the results of these measurements. Table 1 Summary of Short-term Noise Measurement Data Noise Measurement Location (Date, Time) Lmax L(1) L(10) L(50) L(90) Leq Ldn ST-1: ~100 feet from the centerline of Madrone Parkway (10/5/20, 9:50 am -10:00 am)

68 67 58 48 44 55 59-60

Note: The Ldn level at the short-term site is approximated by correlating data to the corresponding levels at the long-term site.

Future Noise Environment The future noise environment at the project site would continue to result primarily from vehicular traffic and from conventional trains along the Union Pacific Railroad. High Speed Rail (HSR) is planned, however, operational noise produced by HSR are speculative at this time as the final alignment has not been selected. Potential HSR noise is not included in this analysis. To determine future traffic noise levels expected along Monterey Road and Madrone Parkway, Year 2025 Cumulative Plus Project peak hour traffic volumes from the nearby Madrone Parkway Carpenters Training Center Project1 were compared to the existing traffic volumes. The increase in peak hour noise levels was conservatively assumed to correlate to the increase expected in day-

1 Initial Study/Mitigated Negative Declaration, Madrone Parkway Carpenters Training Center, City of Morgan Hill, September 2019.


night average noise levels. Year 2025 Cumulative traffic volumes along these roadway segments were calculated to result in traffic noise increases 1 dBA Ldn. Noise due to conventional rail traffic along the UPRR was also conservatively assumed to increase by 1 dBA Ldn. Therefore, the future Ldn is expected to range from 60 dBA to 61 dBA at the small open space area proposed near the Clubhouse, and from 58 to 59 dBA at the patio, tot lot, and open space area proposed on the easternmost portion of the site near Buildings 13 and 14. Exterior noise levels would exceed the City’s 60 dBA Ldn threshold by up to 1 dBA Ldn at the small open space area proposed near the Clubhouse, and would not exceed the threshold at the patio, tot lot, or open space area near Buildings 13 and 14. A review of the site plan shows that the project is consistent with General Plan Policy SSI-8.9. Site planning and design techniques other than sound walls have been implemented to reduce noise impacts, including increasing the distance between the noise source and the receiver, using non-sensitive structures to shield noise-sensitive areas, and orienting buildings to shield outdoor spaces from the noise source. The small outdoor use area proposed on the north side of the Clubhouse would be acoustically shielded on the west, south, and east sides by the building itself, which is approximately 22 feet tall. Noise emanating from Monterey Road, Madrone Parkway, and the UPRR would be mostly shielded by the intervening project buildings with resultant noise levels less than 60 dBA Ldn. An additional noise barrier along the north boundary of this outdoor use area is not recommended as it would not measurably decrease noise levels produced by Monterey Road, Madrone Parkway, and the UPRR. Exterior noise levels at the patio, tot lot, and open space area would also remain below 60 dBA Ldn. With the project, noise produced by the operation of the existing tow and salvage yard would be removed, and additional acoustical shielding of Monterey Road and the UPRR would be provided by 22 to 38-foot tall buildings. An additional noise barrier along the west and south boundary of this outdoor use area is not recommended as resultant noise levels would be less than 60 dBA Ldn.

♦ ♦ ♦

This concludes our assessment of exterior noise levels at the Monterey & Madrone residential project in Morgan Hill. If you have any questions or comments regarding this analysis, please do not hesitate to call. Sincerely yours, Michael S. Thill Principal Consultant ILLINGWORTH & RODKIN, INC. (20-154)

Figure 1 – Site Plan Showing Common Outdoor Activity Areas and Noise Measurement Locations

LT-1 ST-1

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