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HomeMy WebLinkAbout210-SnowStorageAnalysismemo Page 1 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Snow Storage\Norton-SnowStorageAnalysis.docx TO:Matt Ekstrom, PE FROM:Lee Hageman, PE DATE:March 28, 2025 JOB NO.:10678.001 RE:Snow Storage – Norton Ranch Lift Station CC: Urgent For Review Please Comment Please Reply For Your Use This memo presents technical data for the snow storage plan at the Norton Ranch Lift Station. The following design parameters were used to develop a snow storage plan: •A snow depth of 2 feet across the drive access area for a snow volume. o 2,521 sq. ft. of driveway and access area ▪This includes the total concrete driveway area plus the all-weather gravel access pathway. •Snow storage piles may be stacked maximum 8 feet high, with 1:1 (H:V) side slopes. •The (2) proposed snow storage piles will have an area of 662 sq. ft. 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 by placing (3) lifts of loose snow and compacting Snow Storage – Norton Ranch Lift Station Page 2 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 driveway area, it is anticipated that 5,042 cubic feet of snow will need to be removed. Using the compaction factor of 60%, this volume reduces to 2,017 cubic feet (required snow storage volume). Table 1 below summarizes how this volume of removed snow will be stored in the (2) trapezoidal-shaped snow storage piles that can be seen on attached Exhibit 1. Storage piles are located clear of landscaping, public rights-of-way, and outside of vision triangles. Table 1: Snow Storage Piles Pile Number Ave. Width (ft.)Area (sq. ft.)Available Volume (cubic ft.) 1 14 317 1,087 2 13 345 1,062 TOTAL 662 2,148 Note: Volume calculation based on trapezoidal shape As shown in Table 1, the available snow storage volume of 2,148 cubic feet is adequate to accommodate the required storage volume of 2,017 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 reduced by percolation and evaporation. The required snow storage Snow Storage – Norton Ranch Lift Station Page 3 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 driveway and with a Bobcat/Skid Steer type vehicle for moving/piling the snow to designated snow pile locations on-site. Snow will be plowed into piles primarily with the pick-up front plow vehicles during mid-morning hours or when the driveway is likely 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 lot owner will provide this snow storage plan to any snow removal personnel or company. Furthermore, the lot owner pledges to keep drive aisles clear for emergency services and to keep all areas clear of snow as is reasonable. Finally, the lot owner assumes responsibility for all maintenance of sidewalks and ramps utilized to move snow and the lot owner agrees to haul snow off site to a property owned the City of Bozeman in order to maintain emergency access, if necessary. NORTON RANCH LIFT STATION SNOW STORAGE Assumptions: Snow Storage Side Slopes:45 degrees Maximum Storage Height:8 ft Proposed Area of Driveway:2521.16 SF Figure Snow Depth:2 ft Current Snow Storage Area:662 SF Calcs: Required Volume of Snow Storage (w/o compaction):5042.32 CF * calculated w/ an assumed 2' depth w/ 50% compaction 2521 w/ 51.7% compaction 2435 <---- per volume displacement experiment w/ 60% compaction 2017 <---- snow storage required w/ 60.6% compaction 1988 <----per compaction experiment w/ 65% compaction 1765 w/ 70% compaction 1513 6 x 12 Empty Cylinder Weight:278.3 grams Snow Compaction by Volume: Trial 1 47% Total Weight (loose) Total Weight (compacted) Loose Snow Wt. Compacted Snow Wt. Loose/Compac ted Ratio Trial 2 56% Snow Compaction % Compacted Trial 3 52% Trial 1 1399.7 3069.4 1121.4 2791.1 0.402 59.8 Avg. Compaction 51.7% Trial 2 1489.3 3213.9 1211.0 2935.6 0.413 58.7 Trial 3 1326.4 3121.5 1048.1 2843.2 0.369 63.1 4 x8 cylinders Loose (grams): Compacted (grams):Avg. Compaction 60.6 Snow Compaction by Density:Ratio:% Compacted Trial 1 609.4 1266.9 0.481 51.9 Trial 2 749.3 1329.4 0.564 43.6 Side Slopes 1 : 1 Side Slopes 0.5 : 1 Trial 3 672.9 1338.3 0.503 49.7 Pile Number Avg. Width (ft.)Area (sq. ft.)Useable Volume (%) Volume Available (CF) Useable Volume (%) Available Volume (cubic ft.)Avg. Compaction 48.4 1 14 317 42.9 1087 71.4 1811 2 13 345 38.5 1062 69.2 1911 Totals 662 SF 2148 CF 3722 CF Norton-SnowStorageCalculations.xlsx 1 of 1 15S8S8SE E E EEEEE E E E E EEEEE8S8S 8S8S8S15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15S 15SSSSSSSSSSSE WWWWWWWWWWW15S15S15S15S15S15S15SBPBPBPBPBPBPBPBPBPBPBPBPBPBPSSSSSSSS S S S S S S S S S S S S S S S S S S S S S S S S S S SSS FM FM FM FM FM FM FMFMFMFMFMFM FM FM FM FM FM FMFMFMFMFMFME E E E E E E E E E XXXXXXXXXX BP BP BP BP BPBPFM FM FM FM FMFMFMFM FM FM FM FM FM FM FM FM 1 2S2°11'57"W 54.99'S89°31'21"W 117.30' S87°48'03"E 120.00'N0°28'39"W 60.54'2025COPYRIGHT © MORRISON-MAIERLE, INC., SHEET NUMBER PROJECT NUMBER DRAWING NUMBER DATEDESCRIPTIONNO.BY P:\10678-LAUREL PARKWAY LLC\001 - NORTON RANCH LIFT STATION\ACAD\EXHIBITS\SNOWSTORAGE\10678-001_NORTONLS-SNOWSTORAGE.DWG PLOTTED BY:LEEHAGEMAN ON Feb/17/2025 REVISIONS DRAWN BY: DSGN. BY: APPR. BY: DATE: Q.C. REVIEW DATE: BY: 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net engineers surveyors planners scientists MorrisonMaierle VERIFY SCALE AND COLOR! THIS SHEET MAY BE REDUCED AND IS INTENDED TO BE IN COLOR. THE BAR BELOW WILL MEASURE ONE INCH AT ORIGINAL DESIGN SCALE AND RED, GREEN, AND BLUE WILL BE VISIBLE IFREPRODUCED CORRECTLY. MODIFY SCALE ACCORDINGLY! NORTON RANCH LIFT STATION IMPROVEMENTS BOZEMAN MONTANA SNOW STORAGE 10678.001 EX-1 LRH LRH MEE 2/2025 10 205100 SCALE IN FEET SNOW STORAGE PROPOSED SNOW STORAGE PILES AREA CONSIDERED FOR SNOW STORAGE VAUGH DRIVE LAUREL PARKWAYPROPERTY BOUNDARY (TYP.) ASPHALT SHARED USE PATH BUILDING AND EXPANSION CONCRETE DRIVEWAY ALL-WEATHER ACCESS ROAD