Letter to Erik Olsen (County Project Manager) regarding noise study

August 27, 2007

To: Mr. Erik Olsen
Project Manager
Snohomish County PDS
3000 Rockefeller
Everett, WA 98201

Re: F/N 07-101924-000-00-LU
Proposed Granite Falls Motocross Track
Noise Study

Dear Mr. Olsen,

Having reviewed your recent comments to the applicant for the referenced project, I am concerned that the County has not taken a close look at the Noise Study submitted with the application. Snohomish County Code provides some degree of protection for residents in the area of such developments against excessive noise per 30.28.105 and requires the applicant to prove that their ?worst case scenario? operations will not produce noise above certain levels per Chapter 10.01 SCC. As mentioned in several letters to the County regarding this proposal, the noise study provided by the applicant is fundamentally flawed, not verifiable by an objective 3rd party and cannot be relied upon by the County as credible evidence that the SCC provisions regarding noise limits will be met. Outlined below are the details to support the need for the County to insist on a 3rd party noise study, as per SCC 30.28.105(2)(e).

    1. The study performed by Geomatrix Consultants, Inc. for the applicant states that L25 & Lmax at the East property boundary would be 52 and 64 dBA, respectively. These levels are above the level acceptable per SCC which is 49 dBA. The report states in note (d) that the levels would be reduced by the existence of the 25? earthen berm. This is not the case. The earthen berm proposed by the applicant will have little or no effect on reducing the noise level at distances beyond approximately 500? from the berm. This fact has been confirmed in numerous environmental acoustical studies and understood by most state and local authorities. For example, a quote from the Minnesota Department of Transportation, ?Typically, noise reductions are greatest nearest the noise berm/wall. For a residence located near a 20-foot wall, a reduction of about 10 decibels would be typical.  The amount of noise reduction decreases as the listener moves farther away from the wall, and a reduction in noise would be barely perceptible at distances greater than 500 feet.? Refer to: (http://projects.dot.state.mn.us/zrc/212/overview.html). Because all the residents live beyond 500? from the berm, none will benefit acoustically from its construction.
    1. The Noise Assessment study performed by Geomatrix, Inc. for the applicant was not conducted in accordance with a recognized standard generally accepted for ORV noise tests, such as EPA regulation (40 CFR Chapter 1, Section 205.158) and therefore cannot be relied upon by the county to assess the local noise impact. The Geomatrix report states on page 1, ?The review was completed to fulfill the requirements of the Washington Department of Ecology?s State Environmental Policy Act (SEPA).?, yet numerous statements in the report indicate the tests were not performed to Chapter 173-58 WAC, a requirement of WDE/SEPA.
    1. The Noise Assessment study performed by Geomatrix does not provide assurance that the noise levels would meet the requirements set forth in SCC 30.28.105(2)(e)*, ?The projected noise levels in the study shall be based upon the worst-case noise generation scenario for the racetrack use.? When the sound level measurements (upon which the study is based) were taken at Hanegan Speedway in Bellingham, Washington, the observer failed to indicate the number of motorcycles on the track. The applicant indicates that up to 150 riders could use the proposed tracks on weekdays and up to 400 riders could be using the proposed tracks on race weekends. The application provides absolutely no information regarding what the anticipated ?worst case scenario? would be at the proposed track, i.e., what is the highest number of riders using the 5 tracks simultaneously while riding the loudest bikes?? The Noise Study suggests 30 riders maximum, but the application provides no indication that 30 would be the maximum number of riders at one time. The report does not include:

       A.     What the level of noise was at the track in Bellingham during each measurement orB.     The exact number of riders that were on the track while the measurements were being made orC.    What size and types (cubic inch displacement and 2-stroke or 4-stroke) were on the track at the time the measurements were taken These omissions make it impossible for the County to verify that requirements set forth in SCC 30.28.105(2)(e) have been met. It is noteworthy that in your Comments to the applicant (see note d.3) there is a request for a photograph of the Bellingham track on the day the noise level measurements were taken. Such a photograph, stand-alone,  provides absolutely no value in terms of aiding the County in determining Code compliance.

    2. Based on data provided by the California Department of Parks and Recreation and U.S. Environmental Protection Agency, the Noise Study submitted with the application underestimates the noise levels to be expected at the proposed motocross track property boundaries by at least 50%. One specific example: the applicant?s study estimates the L25 level of noise at 600? from the edge of the track at the East boundary would be 52 decibels (see table 2, page 6), 3 decibels above Snohomish County Environmental Noise Limits (SCC 10.01.030). Using basic math and the method used by Geometrix Consultants for calculating Attenuation due to vegetation and distance (these are standard methods used in most noise studies) and then working backwards towards the source, one concludes the noise level (L25) at 150? from the edge of the track would be 71.5 dBA, or approximately 81 dBA at 50? from the track. In an ORV noise study conducted in September of 2005 for the California Department of Parks and Recreation it was concluded that the average dBA reading for a single motocross bike at 50 ft. from the source per EPA F-76a was 89 dBA.  In summary, the results obtained from the applicants noise study indicate that the calculated noise level they measured at 50? from a group of motocross bikes (at the Bellingham track) was 8 dBA less than (or about 50%) the levels measured at the same distance from a single average (in cubic inch displacement)motocross bike per the California study.

A proper Noise Study will conclude the levels of noise at the property boundries of the proposed site would be well above those permitted by SCC, even if the 25? sound berm is taken into account.

Although noise is just one of many concerns held by those living in the area, it is one of the most important. We have lived here for many years and have enjoyed the exceptionally quiet surroundings. Based on the 4 factors listed above, there is an obvious need for the Snohomish County Planning Department to order a 3rd-party Noise Study for this project in order to determine if the project would satisfy Snohomish County Code should it be constructed. 


Jeff Van DattaPresidentStillaguamish Citizens AllianceP.O. Box 1097Granite Falls, WA 98252

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