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HomeMy WebLinkAboutBainbridge Sub 11 - ALT A-2020-0186 Approval Letter October 7, 2020 Kody Daffer Brighton Corporation 2929 W. Navigator Dr., Ste. #400 Meridian, ID 83642 RE: Bainbridge Subdivision No. 11 – Alternative Compliance (H-2020-0186) Dear Mr. Daffer: This letter is to confirm the Director approved your request for alternative compliance to Unified Development Code (UDC) 11-3H-4D.3, which requires noise abatement in the form of a berm or berm and wall in combination a minimum of 10’ higher than the elevation at the centerline of the state highway, be provided for residential uses adjoining state highways. Wall materials are required to consist of impervious concrete or stucco or other appropriate sound attenuating material. Because wood was not considered by Staff to be an appropriate sound attenuating material, a condition of approval of the final plat required the landscape plan to be revised to include a material other than wood for the sound attenuation wall, unless otherwise approved through Alternative Compliance. Accordingly, the Applicant requested wood fencing as depicted on the landscape plan (i.e. 7/8” thick 6-foot tall cedar boards overlapped by 1” to avoid gaps) be considered as an appropriate sound attenuating material based on a letter from a licensed Sound Engineer stating it provides a substantial degree of noise reduction and meets ITD’s and the City’s requirements for such. Additional landscaping is also proposed within the street buffer above and beyond the standards listed in UDC 11-3B-7C resulting in a barrier that allows trees to touch at maturity for additional sound attenuation. The height of the berm/fence combination meets the minimum requirement of 10 feet measured from the centerline of the State Highway and the fence is staggered every 300 feet meeting the minimum UDC requirements. 1. Strict adherence or application of the requirements are not feasible; or The Director finds that strict adherence to the requirement is feasible. 2 2. The alternative compliance provides an equal or superior means for meeting the requirements; and The Director finds that the proposed alternative compliance (i.e. 7/8” thick 6-foot tall cedar boards overlapped by 1” to avoid gaps) meets the sound attenuation requirements of ITD as determined by a Sound Engineer and the height requirements in UDC 11-3H-4D. Additional landscaping within the street buffer that allows trees to touch at maturity as depicted on the landscape plan is also proposed. 3. The alternative means will not be materially detrimental to the public welfare or impair the intended uses and character of surrounding properties. The Director finds the alternative means of compliance will not be materially detrimental to the public welfare or impair the intended uses and character of adjacent properties based on the determination by the Sound Engineer. The additional landscaping should provide an added visual and sound buffer to the state highway. The Applicant, Director, or a Party of Record may request City Council review of a decision of the Director. All requests for review shall be filed in writing with the Planning Division of the Community Development Department on or before October 15, 2020, within fifteen (15) days after the written decision is issued, and contain the information listed in UDC 11-5A-6B. If City Council review of the decision is not requested, the action of the Director represents a final decision on a land use application. You have the right to request a regulatory taking analysis under Idaho Code 67-8003. Thank you for contributing to the success of Meridian. Please help us serve you better in the future. Visit our web-site at www.meridiancity.org/Planning/ to fill out a comment card and give us feedback on how we are doing. Sincerely, Caleb Hood, AICP Planning Division Manager CH:sa Attachments: Sound Engineer Report, Landscape Plan 6 8 9 10 11 12 13 147 5 4 3 2 64636261605958 65 9810099 9697 67 95 94 75 74 73 72 71 69 70 68 89 9085868788 92 93 57 52 53 54 55 56 82 80 79 78 77 83 81 76 4747 41 46 45 44 43 42 40 36 38 37 39 117114115116 51 50 49 48 20 2119171618 33 26 27 28 29 30 31 32 25 23 102 103 104 105 113 112 111 110 109 106 107 101 108 15 66 22 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 BLOCK 1 24 2466 PLANT SCHEDULE LANDSCAPE NOTES TREE PROTECTION NOTES PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE COVER SHEET APPROVED FOR CONSTRUCTION L1.0 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 LANDSCAPE SITE PLAN 0 80 160 240 Plan/Profile Scale: 1" = 80'STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 TREE CALCULATIONS (1TREE/8000SF) STREET TREE CALCULATIONS (1TREE/35 LF) MITIGATION REQUIREMENTS TOTAL TREES REQUIRED/PROVIDED W. BROAD B E N T L N . W. SILVER RIVER LN.N. BOLSENA LN.W. SUNNY C O V E L N .N. BERNACCHI LN.N. SAN VITO LN.W. LOST RAPIDS DR.N. TREE FARM WAYW. CHINDEN BLVD/ HIGHWAY 20/26 FUTURE PHASE BAINBRIDGE NO. 7 KEITH BIRD LEGACY PARK SEE L1.1 SEE L1.2 SEE L1.3 SEE L1.4SEE L1.1SEE L1.3SEE L1.2SEE L1.4BAINBRIDGE NO. 2 CONTACT INFORMATION OWNER/DEVELOPER ENGINEERING & SURVEYING CONSULTANT 08/25/20 COMMUNITY CENTER (SCHEMATIC) N. TREE FARM WAY6 8 9 10 11 12 13 147 5 4 3 2 64636261605958 65 9810099 9697 67 95 94 69 70 68 57 56 22 BLOCK 1 BLOCK 1 66 PLANT SCHEDULE KEY NOTES (TYPICAL) PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE PLAN APPROVED FOR CONSTRUCTION L1.1 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 LANDSCAPE PLAN 0 30 60 90 Plan/Profile Scale: 1" = 30'STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 W. BROAD B E N T L N . W. SILVER RIVER LN.N. BOLSENA LN.N. BERNACCHI LN.N. TREE FARM WAYW. CHINDEN BLVD/ HIGHWAY 20/26 MATCH LINE - SEE L1.2 MATCH LINE - SEE L1.309/29/20 75 74 73 72 71 89 90 85 86 87 88 92 93 52 53 54 55 82 80 79 78 77 83 81 76 4747 41 46 45 44 43 42 40 51 50 49 48 66 BLOCK 1 BLOCK 1 BLOCK 1 PLANT SCHEDULE KEY NOTES (TYPICAL) PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE PLAN APPROVED FOR CONSTRUCTION L1.2 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 LANDSCAPE PLAN 0 30 60 90 Plan/Profile Scale: 1" = 30'STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 N. BOLSENA LN.W. SUNNY C O V E L N .N. TREE FARM WAYMATCH LINE - SEE L1.1 MATCH LINE - SEE L1.4BAINBRIDGE NO. 2 N. BERNACCHI LN.W. LOST R A P I D S D R . 09/29/20 20 211917 16 18 26 27 28 25 23 102 103 104 105 113 112 111 110 109 106 107 101 108 15 BLOCK 1 24 PLANT SCHEDULE KEY NOTES (TYPICAL) GENERAL LANDSCAPE NOTES IRRIGATION GENERAL NOTES PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE PLAN APPROVED FOR CONSTRUCTION L1.3 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 MATCH LINE - SEE L1.4MATCH LINE - SEE L1.1W. SILVER RIVER LN. LANDSCAPE PLAN 0 30 60 90 Plan/Profile Scale: 1" = 30' W. CHINDEN BLVD/ HIGHWAY 20/26 N. SAN VITO LN.FUTURE PHASE 09/29/20 N. BERNACCHI LN. 36 38 37 39 117114115116 33 29 30 31 32 BLOCK 1 BLOCK 1 BLOCK 1 24 PLANT SCHEDULE KEY NOTES (TYPICAL) IRRIGATION GENERAL NOTES PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE PLAN APPROVED FOR CONSTRUCTION L1.4 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 MATCH LINE - SEE L1.3 MATCH LINE - SEE L1.2W. SUNNY COVE LN . W. LOST RAPIDS DR. LANDSCAPE PLAN 0 30 60 90 Plan/Profile Scale: 1" = 30'N. SAN VITO LN.FUTURE PHASE 09/29/20 N. BERNACCHI LN.COMMUNITY CENTER (SCHEMATIC) CONIFEROUS TREE PLANTING AND GUYING DETAIL NTS DECIDUOUS TREE PLANTING AND STAKING DETAIL1NTS2 PLAN SHRUB PLANTING DETAIL NTS3 SHOVEL CUT NTS4 CHINDEN BLVD. W. LOST RAPIDS DRIVE CONIFEROUS TREE PLANTING AND GUYING DETAIL PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE DETAILS APPROVED FOR CONSTRUCTION L1.5 19-136 JUNE 2020 AY LL AY C:\KM ENGINEERING\KM GENERAL - DOCUMENTS\REMOTE WORK\PROJECT\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 9/30/2020, DWG TO PDF.PC3, 22X34 L [PDF]1CITY OF MERIDIAN COMMENTS2/5/202CITY OF MERIDIAN COMMENTS3/2/203QLPE COMMENTS3/16/204SITE SPECIFIC COMMENTS8/25/205CITY REQUESTED LANDSCAPE ADDITIONS9/29/20 STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 WOODEN FENCE65'-FOOT CLEAR VIEW METAL FENCE5 09/29/20 SCHEMATIC SECTION: W. LOST RAPIDS DRIVE 8SCHEMATIC SECTION: W. CHINDEN BLVD(20/26)7 10400 Overland Road #211 -- Boise, ID 83709 www.mullinsacoustics.com 208-514-6264 September 2, 2020 Kameron Nauahi, Assistant Project Manager BRIGHTON CORPORATION 12601 W. Explorer, Suite 200 Boise, ID 83713 Subject: Bainbridge Subdivision #7 project #3828 Phase 11 Sound Wall Analysis Dear Kameron, As requested, I have reviewed your project design in terms of the City of Meridian’s sound wall requirements. This portion of the project is a subdivision with 172 residential lots, fronting along West Chinden Boulevard / State Highway 20/26 and just east of North Tree Farm Way. This letter is an update from September 2018 to cover the newer phase #11 of the project. The barrier as described herein will meet the noise abatement requirements expressed in the Meridian code. REQUIREMENTS The City of Meridian requires a ten foot high berm or barrier wall along major roadways for most noise-sensitive land uses, including residential. This is a blanket requirement, without determining whether traffic noise mitigation is actually needed for a given project. The specific text is: D. Noise abatement shall be required for residential and other noise sensitive uses including, but not limited to, education institutions, churches or places of religious worship, libraries and/or hospitals adjoining state highways: (Ord. 10- 1439, 1-12-2010, eff. 1-18-2010) 1. The applicant shall provide traffic noise abatement by constructing a berm or a berm and wall combination approximately parallel to the state highway. 2. The top of the berm or berm and wall in combination shall be a minimum of ten feet (10') higher than the elevation at the centerline of the state highway. 3. If a wall is proposed, the wall shall meet the following standards: MULLINS ACOUSTICS architectural environmental and industrial noise control a. Wall materials shall be impervious concrete or stucco or other appropriate sound attenuating material. b. Intermittent breaks in the berm or berm and wall in combination will degrade the function and shall not be allowed. c. The applicant shall not construct a monotonous wall. In order to achieve this standard, the applicant may choose one or both of the following variations: (1) The color and/or texture of the wall shall be varied every three hundred (300) linear feet. This could include murals or artwork. (2) The wall shall be staggered every three hundred (300) linear feet subject to subsection D3b of this section that prohibits breaks in the wall. 4. The director may approve alternative compliance as set forth in chapter 5, "Administration", of this title where the applicant has a substitute noise abatement proposal in accord with ITD standards and prepared by a qualified sound engineer. (Ord. 05-1171, 8-30-2005, eff. 9-15-2005) Acoustically relevant text is shown in bold type. A brief review was made of ITD noise criteria published on-line and as referenced in the Meridian ordinance. The key points are: • mitigation must provide at least 5 dB of noise reduction at protected properties • cost per benefitted receptor must be less than $24,500 These are the typical feasibility requirements for evaluating highway noise barriers, as used by most transportation and highway departments around the country. BARRIER The project will include a property line noise barrier as part of its design, as required by the city. This barrier will run along the Chinden Boulevard frontage. The barrier will be approximately 94 feet away from the road centerline, about 52 feet from the nearest edge of a traffic lane, and the setback of the nearest home pads is about 150 feet from the road centerline. This segment of Chinden Boulevard is one lane in each direction, a left turn lane eastbound onto North Tree Farm Way, a right turn lane eastbound onto Tree Farm Way, plus bike lanes on each shoulder. The posted speed limit is 50 mph. This segment of Chinden is mostly level. The property itself where homes will be located will have a final grade roughly 4 feet lower than the road centerline across its entire width. The barrier location is shown on the latest landscape plan (sheet L1.1, stamped October 2019). The heavy black line on this sheet shows the location and extent of the barrier atop the berm, and shows berm contours. Details of the berm and fence are shown as Detail 7 and Detail 6 on sheet L1.5. These drawings confirm the overall 10 foot height of the combined berm/barrier. The roadside noise barrier will be a combination of a four foot high berm and a six foot high wood fence. The cedar fence boards will be 7/8” thick and overlapped by 1” to avoid gaps per notes on sheet L1.5. The barrier top edge will parallel the slight slope of this road segment to maintain a consistent height. Based on a source distance of 25 feet to the nearest (future) traffic lane, 45 feet to the nearest homes behind the barrier, and a ten foot barrier height, the predicted attenuation is 14 dBA. This is a substantial degree of noise reduction, and will easily meet ITD tests for effectiveness. The barrier should extend along the full frontage of the project, shielding lots 6-15 from traffic noise. Additionally an angled segment of barrier should extend along the rear of lot #6 and along its western edge. Starting in the middle of lot #6 the overall height can taper down to just the fence alone. No barrier is needed at lot #4 or for any locations further south. (The drawing shows the fence extending to the southern corner of lot #3 anyway). The design on sheet L1.1 shows the proper placement and orientation of property line barriers and berm details. As the setback distance for lots increases beyond that of lot #4, traffic noise is expected to fall off by at least 8 decibels due to added setback distance from the roadway. This is a noteworthy reduction and comparable to the acoustical value of most barriers. From lot #6 southward, no barrier is needed. Lot #4 and all lots further south will be shielded from traffic noise both by the barrier and by the intervening row of homes when completed. Rows of homes also act as an effective noise barrier. These lots will further benefit from added setback distance from Chinden Boulevard. The future phase to the east (Bainbridge No. 12) will have a similar barrier requirement and barrier design. That future barrier will protect lots 14-15 from traffic noise occurring from beyond the eastern boundary of this property. A similar fence / berm will be required for the adjoining property. An effective traffic noise barrier may consist of a berm, a wall or fence, or any combination of the two. The key elements of an effective noise barrier are: • high enough to break line-of-sight between noise sources and receivers • solid impermeable construction without air gaps • mass of 1.0 psf or more (1/2” thick exterior grade plywood or comparable) No barrier effect occurs until the sight lines between the noise source and the receiver locations are interrupted. As soon as the direct line-of-sight is broken there is immediately 5 dB of attenuation. Then each additional foot of barrier height yields roughly another decibel of attenuation. In this case the LOS is about where the berm ends and the fence begins. Barrier effectiveness is always limited by the geometry (height and horizontal extent). The material itself is almost never the limiting factor for barrier design. The maximum real-world barrier gives about 17 dBA of noise reduction for very tall barriers placed very close to either sources or receivers. In this case, 7/8” thick cedar fence boards weigh about 1.7 pounds per square foot, so they have more than adequate mass to be an effective noise barrier. Plywood of 1/2” thickness will stop about 27 dB of noise, as will sheet metal that is at least 20 gauge. Barriers can be built using plywood, vinyl fencing, cedar fence boards, 1/4” thick acrylic, or similar materials. Masonry and heavier materials are not acoustically necessary. Please let me know if there are any questions. Sincerely, Earl Mullins, PE 7 9 10 11 12 13 14 158 6 5 4 3 65646362616059 66 99101100 9798 68 96 95 70 71 69 58 57 1 2 23 BLOCK 1 BLOCK 1 67 PLANT SCHEDULE KEY NOTES (TYPICAL) PROJECT: DATE:NO.ITEMDATE9233 WEST STATE STREET BOISE, IDAHO 83714 PHONE (208) 639-6939 FAX (208) 639-6930REVISIONS SHEET NO. ENGINEERS . SURVEYORS . PLANNERS CHECKED BY: DRAWN BY: DESIGN BY: DRAWING STATUS:BAINBRIDGE SUBDIVISION NO. 11MERIDIAN, IDAHOLANDSCAPE PLAN FOR AGENCY REVIEW L1.1 19-136 VALUE AY LL AY PRELIMINARY- NOT FOR CONSTRUCTIONP:\19-136\CAD\LANDSCAPE\CONSTRUCTION PLANS\19-136 LANDSCAPE PLAN.DWG, ALYSSA YENSEN, 10/18/2019, DWG TO PDF.PC3, 22X34 L [PDF] LANDSCAPE PLAN 0 30 60 90 Plan/Profile Scale: 1" = 30'STA T E OF IDA H O LICENSE D LANDSCA P E A RCHITECTALYS S A YEN S E NLA-16577 W. BROAD B E N T L N . W. SILVER RIVER LN.N. BOLSENA LN.N. BERNACCHI LN.N. TREE FARM WAYW. CHINDEN BLVD/ HIGHWAY 20/26 MATCH LINE - SEE L1.2 MATCH LINE - SEE L1.310/21/19