Carondelet High School Athletic Fields. Walnut Creek, CA

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1 Attachment 9 Walnut Creek, CA 29 September 2016 Prepared for: Jason White BKF Engineers 1646 North California Boulevard, Suite 400 Walnut Creek, CA jwhite@bkf.com Prepared by: Charles M. Salter Associates, Inc. Benjamin D. Piper Principal Consultant Jeremy L. Decker, PE Principal Consultant 130 Sutter Street, Floor 5 San Francisco, CA Phone: Fax: benjamin.piper@cmsalter.com jeremy.decker@cmsalter.com CSA Project Number:

2 29 September 2016 Page 2 INTRODUCTION This report summarizes our assessment of outdoor noise associated with the proposed new use of the Club Sport Valley Vista complex in Walnut Creek by Carondelet High School. The project will include the addition of a new softball field and lacrosse field, and will reduce the number of tennis courts at the site from 19 to 6. Single-family homes are located north, west, and south of the facility, adjacent to the project. The purpose of our environmental noise assessment is to evaluate potential project related noise in light of the relevant City standards. EXECUTIVE SUMMARY Our measurements and calculations indicate the following: Noise levels associated with Carondelet swimming, tennis, softball, soccer, and lacrosse are expected to meet the noise goals specified in the City General Plan. The public address (PA) system speakers will need to be limited as outlined in this report. Noise levels from Carondelet swim meets are expected to be lower than noise levels from the community swim club meets that recently occurred at the site. o The total attendance levels (or usage ) are expected to be reduced. o In addition, Carondelet will be constructing noise barrier fences around the pool area to further reduce sports activity noise at neighboring properties by approximately 10 db (i.e., half as loud) which would reduce average daily noise to 3 db below the City Ldn 1 criterion. Carondelet will be constructing noise barrier fences along the western edge of the soccer/lacrosse field to further reduce sports activity noise at neighboring properties by approximately 10 db (i.e., half as loud) which would reduce average daily noise to 5 db below the City Ldn criterion. ACOUSTICAL CRITERIA City of Walnut Creek The City of Walnut Creek General Plan 2 includes the following noise standards that are applicable to the project: Action 8.2.1: For new 3 single-family residential projects, use a standard of Ldn 60 db for exterior noise in private use areas. Policy 9.1: Control all residential and commercial noise sources to protect the existing noise environment. Action 9.1.1: Require the evaluation of noise mitigation measures for projects that would cause a substantial increase 4 in noise. 1 Ldn (Day-Night Average Sound Level) A descriptor for a 24-hour A-weighted average noise level. Ldn accounts for the increased sensitivity of people to noise during the nighttime hours. Ldn penalizes sound levels by 10 db during the hours from 10 PM to 7 AM. For practical purposes, the Ldn and CNEL are usually interchangeable. Ldn is sometimes written as DNL Walnut Creek General Plan, City of Walnut Creek, Pages 6-17 through Although the homes adjacent to the sports facility are not new, we are considering the Ldn 60 db standard in our analysis. 4 The City General Plan does not define a substantial increase in noise level. For reference, the City of Concord General Plan (Policy S-2.1.3) defines 4 db as a significant increase in noise level

3 29 September 2016 Page 3 Furthermore, Figure 8 of the General Plan indicates that an exterior noise exposure of Ldn 65 db or less is considered normally acceptable for outdoor sports and recreation land-uses. Ldn 65 to 80 db is considered conditionally acceptable (meaning that specified land-use may be permitted only after detailed analysis of the noise reduction requirements). Exterior noise exposure of Ldn 80 dba or higher is considered unacceptable. Walnut Creek s Municipal Code does not contain property line noise limits applicable to the project. EXISTING NOISE ENVIRONMENT To quantify the existing noise environment at the project site, we conducted four continuous noise measurements from 18 April to 25 April The measurement locations and measured noise levels are shown on Figure 1. Our noise monitors were mounted at an approximate height of 12 feet above grade, except for the noise monitor at Location M4 (see figure), which was located approximately 18 feet above the tennis court grade. The primary measured noise sources were vehicular activity in the parking lot and tennis activity noise. Our measurements did not include a swim meet as those do not occur until later in the season. As indicated on Figure 1, the highest measured Ldn at the site was 55 db which achieves (and is quieter than) the City s normally acceptable threshold of Ldn 65 db for outdoor sports and recreation land-uses. SPORTS ACTIVITY NOISE MEASUREMENTS We measured the following athletic events at other facilities used by Carondelet to quantify the potential noise levels from sports activities that will occur at the site. Carondelet varsity softball at Willow Pass Community Park in Concord on 19 April 2016 (noise monitor approximately 12 feet above grade) See Figure 2 Carondelet swim meet at the De La Salle High School pool on 22 April 2016 (noise monitor at Location S2 approximately 5 feet above grade, noise monitor at Location S3 approximately 12 feet above grade) See Figure 3 Carondelet varsity lacrosse game at Diablo Vista Middle School in Danville on 22 April 2016 (noise monitor approximately 5 feet above grade) See Figure 4 Carondelet lacrosse practice at Ygnacio Valley Park in Concord on 25 April 2016 (noise monitor approximately 12 feet above grade) See Figure 5 Figures 2 to 5 show the measurement locations at each athletic event. Table 1 summarizes the average noise levels (leq(h) 5 ) and maximum noise levels (Lmax 6 ) that we measured from sports activity at each event. 5 Leq(h) The equivalent steady-state A-weighted sound level that, in an hour, would contain the same acoustic energy as the time-varying sound level during the same period. 6 Lmax (Maximum Sound Level) The maximum sound level for a specified measurement period of time as defined in ASTM E1686.

4 29 September 2016 Page 4 Table 1: Sports Activity Noise Levels (dba 7 ) Sport Distance Leq(h) Lmax Cause of Lmax Softball Game Swim Meet Lacrosse Game Lacrosse Practice 50 feet from home plate 50 feet from announcement PA 50 feet from center of field 50 feet from center of field Crowd cheering PA Announcement Referee whistle Coach whistle Additionally, Figure 6 shows various swim meet activity noise levels we measured and compares them to other typical sound levels for reference. ANALYSIS AND RECOMMENDATIONS Overall Sports Activity Noise Though scheduling did not allow us to measure existing swim meet or tennis match noise levels at Valley Vista, we understand that these activities already occur at the project site. BKF Engineers provided us with a table comparing current versus expected monthly usage of the facility. This table is included as Appendix A. We were able to use these numbers to calculate the nominal expected change in noise level that corresponds to the overall change in usage at the facility. This information is shown below in Table 2. Table 2: Overall Estimated Monthly Noise Change from Total Facility Usage Month Existing Usage Proposed Usage Nominal Expected Change in Noise Level (db) January February March April May June July August <1 September October November December A-Weighted Sound Level The A-weighted sound pressure level, expressed in decibels (db). Sometimes the unit of sound level is written as db(a). A weighting is a standard weighting that accounts for the sensitivity of human hearing to the range of audible frequencies. People perceive a 10 db increase in sound level to be twice as loud.

5 29 September 2016 Page 5 Per Appendix A, we expect that noise levels from tennis will decrease. Noise from swimming is discussed in a following section. Softball, lacrosse, and soccer will be new uses at the site. However, overall monthly noise levels from total facility usage, as shown in Table 2, are estimated to increase by less than 2 db. Increases of less than 3 db are typically considered unnoticeable. Traffic and Parking Noise We reviewed the 8 July 2016 traffic study prepared by TJKM Transportation Consultants. Traffic counts were conducted for the months of January, May, August, and November to represent seasonal facility use. Based on the information provided in the study and in Appendix A, we calculated the estimated change in traffic noise levels to be as shown in Table 3. Month Table 3: Estimated Monthly Noise Change from Traffic Existing Proposed Community Daily Vehicle Traffic Proposed Carondelet Total Proposed Change in Noise Level (db) January May August November Our calculations indicate that overall traffic noise levels will decrease at the project site, primarily due to the proposed carpooling scheme. Our methodology for tallying the existing and proposed daily vehicle traffic is described in Appendix B. Swim Meet Activity Noise We understand that there are approximately seven community league swim meets that occur at the existing pool site per year. Per Appendix A there are 175 attendees at the community swim meets. At these swim meets, we understand a PA system is used to play background music and make announcements. The Carondelet swim team schedule indicates that there will be eight home swim meets per year. The monthly usage table in Appendix A shows that there will be 100 attendees at the Carondelet home swim meets. Similar to the community swim meets, there will be a PA system used to play background music and make announcements. Because the Carondelet swim meets will have lower attendance than community swim club meets (100 versus 175), we expect that the Carondelet swim meets will generate lower overall noise levels. We assume that the PA system used at the Carondelet swim meets will be similar to the system currently used at the community swim club meets and the whistle/buzzer noise used to start races will also be similar. Therefore, we do not expect that Lmax noise levels from these sources will be higher. However, because there will be more swim meets at the site per year, they will likely occur more frequently on an annual basis.

6 29 September 2016 Page 6 In general, Carondelet swimming activity noise is expected to be similar to existing swimming activity noise. The existing swimming activity noise likely exceeds the City s Ldn 60 dba property line noise criterion. To achieve this criterion for the school swim meets, our calculations indicate that the following PA system speaker(s) controls should be implemented. The speaker(s) should be located at a maximum height of five feet above the pool deck The speaker(s) should be located a minimum of 75 feet from the nearest property line The speaker volume should be limited to average 65 dba at a distance of 50 feet from the speaker(s) Field Sport Activity Noise The field sports (lacrosse, soccer, and softball) will be new uses at the project site. We understand there is a desire to have a PA system for background music and announcements at these events as well. PA systems were not used at the softball and lacrosse games we measured. Thus, our analysis of PA noise at these events is based on PA noise we measured at the Carondelet swim meet and the information provided by the school, discussed below. We understand that the school would like to use a portable ground-level PA system at games (but not practices). Warm-up music will be played approximately 45 minutes prior to game time, but will not be played during or after games. The PA system will be used for sporadic announcements, but not for play-by-play announcements. Based on our analysis, the following speaker design conditions should be implemented. The speaker(s) should be located at a maximum height of five feet above the field grade The speaker(s) should be located a minimum of 75 feet from the nearest property line The speaker volume should be limited to average 65 dba at a distance of 50 feet from the speaker(s) Daily Sports Activity Noise Policy of the City General Plan specifies an exterior noise level of Ldn 60 as a project goal for new single-family housing. Ldn is a metric used to describe the average noise level over a 24-hour period. Using our measurements of the various sports activities, we calculated the expected increase in Ldn attributable to each activity at the property line of the nearest single-family home. The results of our calculations are summarized in Table 4. For our calculations, we have assumed the PA system controls specified in the Swim Meet Activity Noise and Field Sport Activity Noise sections of this report will be implemented.

7 29 September 2016 Page 7 Table 4: Expected Ldn Increase from Sports Activity Noise, Per Noise Measurements Sport Measured Existing Ldn at Residential Property Line Nearest to Proposed Field/Pool Location Calculated Ldn at Nearest Residential Property Line with Sports Activity Ldn Increase due to Sports Activity Softball Game Swim Meet Lacrosse Game Soccer Game Lacrosse Practice Our calculations indicate that the Ldn increase from sporting event and practice noise at the nearest property line will not be substantial. Based on comments from the school, we understand that the PA system will be used for games only. Thus, we have not factored PA system noise into our calculations for lacrosse practice. Though not measured, practices for other sports would likely be similar to the measured lacrosse practice, and therefore quieter than the City noise standard. Our calculated Ldn assumes that the noise barrier fences described in the following section will be implemented. Noise Barrier Fences Though not necessary to achieve the City noise criterion, we understand that Carondelet will be constructing noise barrier fences at the pool area and soccer/lacrosse field to further reduce noise to the adjacent properties. The fences will be continuous from grade-to-top with no cracks or gaps (including at the ground) and will be constructed to have a minimum surface density of 3 psf (such as double-layer redwood boards with offset joints). The fences will have a minimum height of eight feet above the grade of the pool deck and field. The fences around the pool area will be located on the north and west property lines at the perimeter of the pool area. Where there are existing buildings along the western property line, the buildings will serve as a barrier. Thus the fence does not need to extend behind (to the west of) the existing buildings. The portion of the fence along the northern property line will extend from the western edge of the site to the existing gym building (a length of approximately 200 feet). The fence at the field area will be located along the western property line and extend from the northern property line to the southern property line. We calculate that the barriers will reduce sport activity noise by approximately 10 db during practices and events. The reduced level would be perceived as half as loud. The swim meets would only occur for a few hours during the day. Consequently, the noise barriers would result in average daily noise levels (Ldn) that are three db quieter (reduced from 60 db to 57 db). This is enough to be considered a noticeable reduction in environmental noise levels. 8 Because it is not currently soccer season, we were unable to measure soccer activity noise. Therefore, we have calculated expected soccer activity noise based on the usage table in Appendix A and the lacrosse noise levels we measured.

8 29 September 2016 Page 8 CONCLUSIONS Our measurements at the project site (see Figure 1) indicate that exterior noise exposure at the site is less than Ldn 65 db. Per the City General Plan, this is acceptable for outdoor sports and recreation land-uses. Based on our measurements and calculations, it appears that noise levels associated with Carondelet swimming, tennis, softball, soccer, and lacrosse sporting events will meet the City noise goals. The noise barrier fences that the school proposes to construct at the pool area and field will further reduce sports activity noise transfer to the adjacent residential properties to be at least 3 db below the City criterion (which is considered to be a noticeable amount). * * * This concludes our exterior noise assessment for the Carondelet athletic fields project at Valley Vista Sports Complex. If you have any questions, please let us know.

9 29 September 2016 Page 9 APPENDIX A

10 29 September 2016 Page 10 For reference, Table 3 of our report is shown below. Month APPENDIX B TRAFFIC COUNT METHODOLOGY Table 3: Estimated Monthly Noise Change from Traffic Existing Proposed Community Daily Vehicle Traffic Proposed Carondelet Total Proposed Change in Noise Level (db) January May August November The existing traffic count numbers shown in Table 3 are taken from Table 4 of the TJKM traffic study. Our methodology for calculating the proposed daily traffic numbers is as follows. Per Appendix A, Note 1 the TOTAL MAX USERS = TOTAL TENNIS + TOTAL GYM + HIGHEST SPORT USER TOTAL + 30 (CARONDELET IN-SEASON PRACTICE). For the months of January, May, August, and November, these values are 230, 240, 214, and 214 respectively. Per the traffic study, community-use assumes one user per vehicle multiplied by two trips each (one coming and one going). Per the traffic study, Carondelet-use assumes three users per vehicle (carpooling), multiplied by two trips each (one coming and one going). The following is a sample calculation for the month of January Per Appendix A, the TOTAL MAX USERS in January is 230 Community Use: 40 (tennis) + 10 (aquatics) + 15 (gym) = 65 users Proposed Community Daily Vehicle Traffic: 65 users x 2 trips per user = 130 trips Carondelet Use: 230 users 65 users = 165 users Proposed Carondelet Daily Vehicle Traffic: (165 users per carpool/3 users) x 2 trips per carpool = 110 trips Total Proposed Daily Vehicle Traffic: 130 trips trips = 240 trips Traffic numbers for the other months are calculated similarly.

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