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HomeMy WebLinkAbout019 Appendix L - Snow Storage Analysismemo Page 1 TO: James Nickelson, PE FROM: Celine Saucier, PE DATE: September 16, 2022 JOB NO.: 10130.001.02 RE: Snow Storage – West Park Neighborhood, Block 1 Lot 1 CC: Urgent For Review Please Comment Please Reply For Your Use This memo presents technical data for the snow storage plan at the West Park Apartments. The following design parameters were used to develop a snow storage plan: • A snow depth of 2 feet across the asphalt parking area for a snow volume. • Snow storage piles may be stacked maximum 8 feet high, with 2:1 side slopes. • 69,191.00 sq. ft. of parking area (this is the total asphalt area, including drive aisles and parking stalls) that will require snow removal into storage piles. • The (13) proposed snow storage piles will have an area of 9,909 sq. ft. (Table 1). In addition to the City of Bozeman recommendations, an in-house analysis was conducted to arrive at a “compaction factor.” The compaction factor is to try and approximate the percent compaction the snow receives as plows remove it from its original state. On January 30, 2018, Bozeman, MT received several inches of new snow as temperatures dipped into the teens overnight. The following day, measurements were taken of the weight of loosely placed snow in an empty 6” x 12” cylinder. The weight of compacted snow was also recorded, and done so by placing (3) lifts of loose snow and compacting each lift. It was observed by (3) separate trials that loose snow was approximately 40% the weight of the well-compacted snow in this controlled environment. Thus, it was concluded that loose snow compacts to about 40% of its original volume, or the compaction factor is approximately 60%. Snow Storage – West Park Neighborhood, Lot 1 Page 2 Using a snow depth of 2 feet across the asphalt area, it is anticipated that 138,382 cubic feet of snow will need to be removed. Using the aforementioned compaction factor of 60%, this volume reduces to 55,353 cubic feet (required snow storage volume). Table 1 below summarizes how this volume of removed snow will easily be stored in the (13) trapezoidal-shaped snow storage piles that can be seen on attached Figure 1. Storage piles are located clear of landscaping, public right-of-ways, and outside of vision triangles. Pile Number Avg. Width (ft.) Area (sq. ft.) Available Volume (cubic ft.) 1 22 392 2566 2 15 1090 6395 3 14 250 1429 4 9 159 707 5 5 1080 1728 6 9 318 1413 7 9 318 1413 8 9 636 2827 9 9 318 1413 10 9 318 1413 11 9 159 707 12 112 4453 34352 13 18 418 2601 Totals 9079 58963 *Volume calculation based on trapezoidal shape Table 1: Snow Storage Volume Calculation As shown in Table 1, the available snow storage volume of 58,963 cubic feet is adequate to accommodate the required storage volume of 55,353 cubic feet. This design approach is a conservative estimate of how much snow storage volume is required because it does not implement other obvious factors that will affect snow storage volume. Storage piles will inevitably be subject to freezing and thawing cycles. During these cycles, storage piles will be Snow Storage – West Park Neighborhood, Lot 1 Page 3 reduced by percolation and evaporation. The required snow storage volume will also be affected due to vehicles in the parking area prohibiting the removal of all the snow. These factors were not taken into account in our required volume calculations. Moving the snow to the designated pile locations will ultimately be up to the contractor hired, however, pile locations were designed with the following anticipated removal plan: The snow will be cleared using full size pick-up trucks to plow the drive aisles and with a Bobcat/Skid Steer type vehicle for moving/piling the snow to designated snow pile locations on-site. Snow will be plowed to Piles 1 through 13 primarily with the pick-up front plow vehicles during mid-morning hours when the parking lot will be mostly empty. If necessary, the Bobcat/Skid Steer will be utilized to pile snow in these locations up to the allowable 8-ft snow pile height. The Bobcat/Skid Steer model that will be utilized will likely be a New Holland L160, which has a bucket reach of 11’7” and will allow it to easily pile the snow to the 8-ft height. The applicant will provide this snow storage plan to any third party providing snow removal services. Furthermore, the applicant pledges to keep drive aisles clear for emergency services and to keep all areas clear of snow as is reasonable. Finally, the applicant assumes responsibility for all maintenance of sidewalks and ramps utilized to move snow and the applicant agrees to haul snow off site to a property owned by a member of the development group for this project, if necessary, in order to maintain parking and emergency access. LAUREL PARKWAY VAUGHN DRIVEVAUGHN DRIVEOPENSPACEOPENSPACEPBBP BP BP BP BP BP BP BP BP BP BP BP BP BP BP BP BP BP BPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBP 408020400SCALE IN FEET XBLOCK 1LOT 1SNOW STORAGEPROPOSED SNOW STORAGE PILESAREA CONSIDERED FOR SNOW STORAGEPILE NUMBER12345671211109813FIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE,2022Plotted by rosie nickelson on Sep/16/2022engineers surveyors planners scientistsMorrisonMaierle1 Engineering PlaceHelena, MT 59602406.442.3050www.m-m.netN:\10130\001.02 Site Plan\ACAD\Exhibits\10130.001.02_Snow Storage.dwg 10130.001.02 EX AWEST PARK SUBDIVISIONBLOCK 1, LOT 1 BOZEMANMTSNOW STORAGE EXHIBITRSNCMSJRN09/2022