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HomeMy WebLinkAboutSnowStorageMemomemo Page 1 TO: Matt Ekstrom, PE FROM: Jordyn Mallett (updated 10/29/2021 by Kevin Jacobsen) DATE: 09/08/2021 (updated 10/29/2021) JOB NO.: 5305.008 RE: Snow Storage – NWX Apartments CC: Urgent For Review Please Comment Please Reply For Your Use This memo presents technical data for the snow storage plan at the NWX Apartments located in Northwest Crossing Subdivision. 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. · A total of 261,780 SF of parking area (this is the total asphalt area, including drive aisles and parking stalls) that will require snow removal into storage piles. · The proposed snow storage piles will have a total footprint of approximately 47,020 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 approximates 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%. Using a snow depth of 2 feet across the asphalt area, it is anticipated that a total of 523,560 cubic feet of snow will need to be removed. Using the compaction factor of 60%, this volume reduces to 209,424 cubic feet (total required snow storage volume). Based on the site geometry, the development has been broken into three regions, north, south, and east, as summarized in Table 1, below. This table summarizes how the volume of removed snow for each region will easily be stored in trapezoidal-shaped snow storage piles as shown on the attached Exhibit 1. Proposed storage piles are generally located within parking islands and parking bays and are clear of public rights-of-way and outside of vision triangles. The project will provide approximately 79 parking spaces more than the zoning-required minimum, and the reduction of parking spaces due to snow storage (118 spaces) will require the owner to haul off snow from the site during large accumulations of snowfall to not impact the amount of available parking. Snow Storage – NWX Apartments Page 2 Region Asphalt Area (SF) Total Snow (CF) Req'd Snow Storage (40%) (CF) North 98,800 197,600 79,040 South 117,940 235,880 94,352 East 45,040 90,080 36,032 TOTAL 261,780 523,560 209,424 *Volume calculation based on a 2’ snow depth across all paved areas. Table 1: Required Snow Storage Volumes Pile Number Base Area (SF) Available Volume (CF) North N1 230 330 N2 230 350 N3 250 230 N4 1,000 1,710 N5 200 280 N6 370 530 N7 200 230 N8 470 920 N9 390 560 N10 310 370 N11 12,740 75,260 SUBTOTAL 16,390 80,770 South S1 370 600 S2 370 600 S3 370 600 S4 370 600 S5 370 600 S6 370 600 S7 370 600 S8 370 600 S9 200 320 S10 N/A N/A S11 730 570 S12 230 240 S13 230 240 S14 230 240 S15 230 240 S16 230 240 Snow Storage – NWX Apartments Page 3 S17 1,190 1,900 S18 5,880 33,180 S19 4,930 25,620 S20 4,730 28,120 SUBTOTAL 21,770 95,710 East E1 1,850 8,000 E2 250 230 E3 220 180 E4 250 360 E5 1,250 1,980 E6 210 260 E7 280 490 E8 290 610 E9 4,260 21,400 E10 980 2,760 SUBTOTAL 8,860 36,270 *Volume calculation based on trapezoidal shape with 2:1 side slopes and a maximum height of 8’ Table 2: Snow Storage Volume Calculation As shown in the tables above, the available snow storage volume (212,750 CF) is adequate to accommodate the total required storage volume of 209,424 cubic feet. However, with the housing density of the site, some of the snow storage piles are located in parking bays. The project will provide approximately 79 parking spaces more than the zoning-required minimum, and the reduction of parking spaces due to snow storage (122 spaces) will require the owner to haul off snow from the site during large accumulations of snowfall in order to not impact the amount of available parking. 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 reduced by percolation, sublimation, 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. C37L49S78°41'34"W547.89'N78°41'34"E447.36'C39 C35 C38 C34 C45L61C47C54L65 C57 C56 0.75 acs.C37L49S78°41'34"W547.89'N78°41'34"E447.36'C39 C35 C38 C34 C45L61C47C54L65 C57 C56 0.75 acs.FIREDOMESTI CFIREDOMESTIC 6" FIRE 4" DOMESTIC 6" FIRE4" DOMESTIC 6" FIRE 2" DOMESTIC 6" FIRE2" DOMESTIC 6" FIRE 4" DOM E ST I C MWTPTPCOMWSDSDSDSDDSD SD SDSDDDSDSDDD DSDDSD DSDDSD SDDDDDDE1E5SNOW STORAGE AREA: EASTTOTAL ASPHALT AREA: 45,040 SFREQ'D SNOW STORAGE: 36,032 CFSNOW STORAGE AREA: NORTHTOTAL ASPHALT AREA: 98,800 SFREQ'D SNOW STORAGE: 79,040 CFE2E3E4E6E7E8E9N1N2N3N4N5N6N7N8N9N10N11S17S14S15S16E10VERIFY SCALE!THESE PRINTS MAY BE REDUCED.LINE BELOW MEASURES ONE INCHON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY!2021COPYRIGHT © MORRISON-MAIERLE, INC.,SHEET NUMBERPROJECT NUMBERDRAWING NUMBERDATEDESCRIPTIONNO.BYN:\5305\008 - NW CROSSING MULTI FAMILY\ACAD\EXHIBITS\SNOW STORAGE EXHIBIT.DWG PLOTTED BY:KEVIN D. JACOBSEN ON Oct/29/2021REVISIONSDRAWN BY:DSGN. BY:APPR. BY:DATE:Q.C. REVIEWDATE:BY:2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netengineers surveyors planners scientistsMorrisonMaierleICON AT NORTHWEST CROSSINGBOZEMANMONTANASNOW STORAGE SITE PLAN5305.008SNOW-1JEM---10/2021#####################408020400SCALE IN FEET##TWIN LAKES AVENUEWELLSPRING DRIVEHARVEST PARKWAYROSA WAYPHASE 1PHASE 2PHASE 1SNOW STORAGEAREA (TYP.)SNOW REMOVALAREA (TYP.) C39 C35 C38 C34 C45L65 C57 C56 C39 C35 C38 C34 C45L65 C57 C56 6" FIRE4" DOMESTIC 6" FIRE 4" DOMESTIC 6" FIRE4" DOMESTIC 6" FIRE4" DOMESTIC 6" FIRE2" DOMESTIC 6" FIR E 2" DOME S TI C 6" FIRE2" DOME S T IC 6" FIRE2" DOMESTICWVWVWVWVWVWVWVWVWVWVWVWVEWEWEWEWEWDDSDSDSDSDSDSDSD SD SD SD SD SDSDDDDDSD SD SD SD SD SD SD SD SDD DSDDSD SDSDSDDDDDDE1S19SNOW STORAGE AREA: NORTHTOTAL ASPHALT AREA: 98,800 SFREQ'D SNOW STORAGE: 79,040 CFSNOW STORAGE AREA: SOUTHTOTAL ASPHALT AREA: 117,940 SFREQ'D SNOW STORAGE: 94,352 CFE8S1S2S9S11S17S18S3S4S4S6S7S8S12S13S14S15S16S20VERIFY SCALE!THESE PRINTS MAY BE REDUCED.LINE BELOW MEASURES ONE INCHON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY!2021COPYRIGHT © MORRISON-MAIERLE, INC.,SHEET NUMBERPROJECT NUMBERDRAWING NUMBERDATEDESCRIPTIONNO.BYN:\5305\008 - NW CROSSING MULTI FAMILY\ACAD\EXHIBITS\SNOW STORAGE EXHIBIT.DWG PLOTTED BY:KEVIN D. JACOBSEN ON Oct/29/2021REVISIONSDRAWN BY:DSGN. BY:APPR. BY:DATE:Q.C. REVIEWDATE:BY:2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netengineers surveyors planners scientistsMorrisonMaierleICON AT NORTHWEST CROSSINGBOZEMANMONTANASNOW STORAGE SITE PLAN5305.008SNOW-2JEM---10/2021#####################408020400SCALE IN FEET##TWIN LAKES AVENUEWELLSPRING DRIVEROSA WAYWEST OAK STREETPHASE 1PHASE 2PHASE 1SNOW STORAGEAREA (TYP.)SNOW REMOVALAREA (TYP.)