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HomeMy WebLinkAboutSWEETWATER BREWING - BEER GARDEN - MJA210004 - DOCUMENT MARKUPS - ROUND 3 - DRAINAGE REPORT NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE MEMO: WATERFIELD MAJOR SITE PLAN AMENDMENT FORT COLLINS | GREELEY 1 | 4 October 19, 2021 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 RE: DRAINAGE MEMO FOR LOT 1 & 2, FORT COLLINS BREWERY SWEETWATER BREWING MAJOR AMENDMENT CITY OF FORT COLLINS, COLORADO PROJECT NUMBER: 100-033 Dear Staff: Sweetwater Brewing has bought the property previously developed by Fort Collins Brewery and previously occupied by Red Truck Brewing Company. Sweetwater Brewing is proposing a major site plan amendment to allow for a revised parking lot shifted into the undeveloped Lot 1 of the original Fort Collins Brewery Plat. The proposed improvements consist of a new parking lot shifted west from its existing condition and additional parking spaces in the northwest corner of Lot 1. This area of the property was previously analyzed as part of the Final Drainage, Erosion Control and Water Quality Report for Fort Collins Brewery, Fort Collins, Colorado prepared by Apex Engineering dated April 20, 2009. This area was also amended as part of the Red Truck Brewery – Minor Amendment prepared by Apex Engineering dated August 23, 2017. The proposed improvements are located on the northwest corner and along the west side of the existing building. The existing area consists of a parking lot along with sidewalk, landscaping, and a portion an outdoor patio at the southwest corner of the building. Lot 1 consists of gravel surfacing. The existing area sheet drains to the northeast to an inlet in the center of the drive aisle which conveys the runoff to the site’s detention pond at the SE corner of the lot. The proposed improvements have been delineated into four separate basins described in detail below. Basin A1 consists of 0.40 acres of a proposed parking lot, sidewalk, and a proposed rain garden. Flows from this basin will sheet drain across the parking lot and be conveyed via curb and gutter to a sidewalk chase that discharges into the rain garden which will treat the water quality control volume up to 10” of depth. This runoff will discharge via underdrain following treatment into the existing storm line in the existing drive aisle to the north. The sidewalk chase and rain garden overflow curb cut will be able to convey the 100-year storm event. This basin generates 0.88 cfs in the minor storm and 3.84 cfs in the 100-year with a percent impervious of 75%. Basins A1 contains 0.30 acres of the total 0.38 acres of the newly added or modified impervious area. This is 79% of the impervious area for the project. The basin consists of the area that will be treated by the proposed rain garden to meet Low Impact Development requirements. The effective imperviousness is 75% requiring a WQCV of 419 cf. 450 cf is provided with a ponding depth of 10”. An underdrain system will collect the WQCV and discharge it into the existing storm line in the north drive aisle. Basin B1 consists of 0.42 acres of the existing parking lot, a portion of the existing roof, pedestrian facilities, and landscaping. Flows from this basin will follow the existing drainage patterns of the existing parking lot by being conveyed in the center of the drive aisle and collected by a proposed area inlet installed in the existing pavement. A 15” storm line will then convey the basins flow to the existing storm line in the drive aisle to the north. Flows from this basin will be treated for water quality and detained in the existing detention pond at the NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE MEMO: WATERFIELD MAJOR SITE PLAN AMENDMENT FORT COLLINS | GREELEY 2 | 4 southeast corner of the property. This basin generates 1.08 cfs in the minor storm event and 4.16 cfs in the 100- year event with a percent impervious area of 91%. Basin C1 consists of 0.11 acres of the rest of the proposed parking lot, existing trash enclosure, and landscaping. Flows from this basin will sheet drain to the center of the drive aisle which is then conveyed to an existing storm inlet which is eventually conveyed to the site’s existing detention pond. This basin is not treated through the proposed rain garden but is accounted for in the existing pond both for water quality and the 100-year detention volume. This basin generates 0.30 cfs in the minor storm event and 1.14 cfs in the 100-year event with a percent impervious of 94%. Basin D1 consists of 0.07 acres of landscaping. Flows from this basin follow the existing drainage paths of draining onto the adjacent lots to the west and north. This basin generates 0.05 cfs in the minor storm and 0.21 cfs in the 100-year event with a percent impervious of 2%. As this is the existing condition and the imperviousness is not increasing, this flow is considered negligible. The existing detention pond was designed with a water quality storage volume of 0.094 acre-ft which is treated through the pond’s outlet structure. The pond was also designed with a 100-year storage volume of 0.99 acre-ft. This was based on a percent impervious of 83% for an area of 2.70 acres. The proposed percent impervious of the entire site is 75% meaning the existing infrastructure is adequately sized for the proposed improvements with no negative impact. The narrative for the Fort Collins Brewery project indicated that the existing parking lot was designed to detain 0.17 acre-ft of the 100-year storm event at an elevation of 4940.42 NVGD 29. After the drainage certification and a slight increase in impervious area due to the Red Truck Brewing minor amendment, the 100-WSEL was increased to 4940.60. These elevations were established using the NVGD 29 datum. The Sweetwater Brewing Major Amendment used NAVD88 requiring a conversion of the existing WSEL which comes out to NVGD 29 + 3.18’ = 4943.78. The proposed improvements will fill and alter a portion of the previously designed parking inundation area, thereby needing to accommodate this detention volume in the proposed improvements. The existing parking lot grading combined with the proposed improvement grading (both Sweetwater Major and Minor Amendment projects) was analyzed to determine the proposed parking lot detention storage volume. Based on a topographic survey performed by Northern Engineering on July 6th, 2021, a stage storage exhibit was created to determine the revised parking lot storage (including both the Sweetwater Tank Farm and Sweetwater Beer Garden projects) at the 100-year WSEL. The volume is accommodated at the required 0.17 acre-ft which is in compliance with the approved Final Drainage, Erosion Control and Water Quality Report for Fort Collins Brewery, Fort Collins, Colorado dated April 20, 2009 along with the Drainage Memo for the Red Truck Brewery – Minor Amendment dated August 23, 2017. The overall stormwater management strategy employed with the Sweetwater Beer Garden project utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peaks, volumes, and pollutant loads as the site is redeveloped from the current use by implementing multiple Low-Impact Development (LID) strategies including: Selecting a site that has been previously developed to reduce development impacts. Routing flows, to the extent feasible, through a bioretention pond located for water quality purposes. Stormwater will be routed through the bioretention filter material to increase infiltration. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE MEMO: WATERFIELD MAJOR SITE PLAN AMENDMENT FORT COLLINS | GREELEY 3 | 4 Through existing on-site detention, the time of concentration will increase and reduce loads on downstream storm infrastructure. Providing a bioretention facility that will treat 75% of the newly added impervious area for additional treatment prior to the existing water quality pond. Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban development of this intensity will still generate stormwater runoff that will require additional BMPs and water quality. The majority of stormwater runoff from the site will be intercepted and treated using bioretention. The rest will flow and be conveyed directly to the existing water quality pond at the southeast corner of the site. Step 3 – Stabilize Drainageways Low Impact Development aids in the stabilization of drainageways by reducing runoff from development. This reduction in runoff will in turn reduce the total flow in drainageways during storm events. Step 4 – Implement Site Specific and Other Source Control BMPs. The proposed project includes a concrete parking lot and pedestrian sidewalks, all of which will require the need for site specific source controls including: A existing trash enclosure on the northwest corner of the property. The proposed development will provide LID features within the existing water quality pond to provide enhanced water quality. The bioretention facility is designed to capture the first flush storm event for basin A1; thus, eliminating sources of potential pollution previously left exposed to weathering and runoff processes. The revised impervious area for the project is less than the previously approved impervious area for Fort Collins Brewery from the approved drainage report. The approved percent impervious was 83% for an area of 2.70 acres. The percent impervious of the property including the improvements is 75% for the same 2.70 acres. This is less than the approved percent impervious. The decrease in percent impervious will not negatively impact the existing drainage infrastructure. The proposed improvements are in compliance with the approved Final Drainage, Erosion Control and Water Quality Report for Fort Collins Brewery, Fort Collins, Colorado dated April 20, 2009. NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE MEMO: WATERFIELD MAJOR SITE PLAN AMENDMENT FORT COLLINS | GREELEY 4 | 4 If you should have any questions or comments, please feel free to contact us at your convenience. Sincerely, NORTHERN ENGINEERING SERVICES, INC. STEPHANIE THOMAS, PE Project Manager Attachments · Attachment A Rational Calculations · Attachment B Storm Sewer Calculations · Attachment C Rain Garden Calculations · Attachment D Drainage Exhibits · Attachment E LID Treatment Area Exhibit Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =75.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.750 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.24 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 17,476 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =349 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =10 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 0.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin =262 sq ft D) Actual Flat Surface Area AActual =540 sq ft E) Area at Design Depth (Top Surface Area)ATop =540 sq ft F) Rain Garden Total Volume VT=450 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =cu ft iii) Orifice Diameter, 3/8" Minimum DO = in Design Procedure Form: Rain Garden (RG) Cody Pape Northern Engineering October 18, 2021 100-033 - Sweetwater Brewing UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 100-033_LID Sizing, RG 10/18/2021, 3:59 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? PROVIDE A 30 MIL (MIN) PVC LINER WITH CDOT CLASS B GEOTEXTILE ABOVE IT. USE THE SAME GEOTEXTILE BELOW THE LINER IF THE SUBGRADE IS ANGULAR 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) Cody Pape Northern Engineering October 18, 2021 100-033 - Sweetwater Brewing Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO 100-033_LID Sizing, RG 10/18/2021, 3:59 PM SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSTELECABLEVAULTF.O.ELECVAULTF.O.VAULTF.O.VAULTF.O.ELECELECCONTROLIRRFDCCONTROLIRRELECELECBRKRELECBRKREEEEEEEEEEEEEEEEEEEEEEEEEEGGGGGGGGGWWWWWWEEE E E E E E E EGGFOFOEEEEE CTVCTVCTVGGE E E EEEEEEFO EEEEEEGGGGGGGGGGGG G G G G G FO FOFOFOFOFOFOW W W W W W W W W WEEEEFOFOFOFOFOFOFOFOEEEEEEWWWWWXXXXXXXXXXXSTSTSTSTSTSTSTSTSTSTSTSTCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVCTVEEEEEEEEEEEEEWWWWEEEEEEEEEEESSSSSSSSSSSSSSSSSSEAST LINCOLN AVENUEX XXXXXUD225 LEMAY LLC225 N LEMAY AVEA1B1D1EX1EXISTING 10'UTILITY EASEMENTEXISTING UTILITY ANDDRAINAGE EASEMENTEXISTING 30'ACCESS, EMERGENCY ACCESS,UTILITY AND DRAINAGE EASEMENTEXISTING UTILITY ANDDRAINAGE EAESMENTPROPOSED 2' SIDEWALK CHASEEXISTING INLETEXISTING SWALEEXISTING DRAINAGE AND UTILITY EASEMENTPROPOSEDRAIN GARDENPROPOSED TANK FARMSEE SWEETWATER BREWING TANK FARMFOR DESIGN.EXISTING BREWERY BUILDINGFFE: 4945.26PROPOSED 100-YEAR OVERFLOW2' CURB CUT AT ELEVATION: 4943.54EXISTING DRAINAGEEASEMENT100-YEAR WSELINUNDATION AREAEXISTING INLETEXISTING INLETEXISTING INLETC1PROPOSED INLET24' ACCESS &EMERGENCYACCESS EASEMENTPROPOSED UTILITY ANDDRAINAGE EASEMENTUTILITY EASEMENT30' ACCESS, EMERGENCY ACCESS,UTILITY & DRAINAGE EASEMENT10' UTILITYEASEMENT25' DRAINAGEEASEMENT30' DRAINAGEEASEMENT30' UTILITY &DRAINAGEEASEMENT30' UTILITY &DRAINAGEEASEMENTEXISTING 10'UTILITY EASEMENT17' UTILITYEASEMENTACCESS, EMERGENCYACCESS, & UTILITY EASEMENTPROPOSEDSTORM DRAIN15' UTILITY &DRAINAGE EASEMENTEXISTING 15'UTILITY EAEMENT15' UTILITY &DRAINAGE EASEMENTCALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOUDIG, GRADE, OR EXCAVATE FOR THE MARKING OFUNDERGROUND MEMBER UTILITIES.CALL UTILITY NOTIFICATION CENTER OFCOLORADOKnow what'sbelow.before you dig.CallRNORTH( IN FEET )1 inch = ft.Feet02020204060FOR DRAINAGE REVIEW ONLYNOT FOR CONSTRUCTIONLEGEND:PROPOSED CONTOURPROPOSED STORM SEWERPROPOSED SWALEEXISTING CONTOURPROPOSED CURB & GUTTERPROPOSED INLETADESIGN POINTFLOW ARROWDRAINAGE BASIN LABELDRAINAGE BASIN BOUNDARYNOTES:1.REFER TO THE "FINAL DRAINAGE, EROSION CONTROL AND WATER QUALITYREPORT FOR FORT COLLINS BREWERY" DATED APRIL 20, 2009 AND "DRAINAGEMEMO RED TRUCK BREWERY - MINOR AMENDMENT" DATED AUGUST 23, 2017, BYAPEX ENGINEERING FOR PREVIOUSLY APPROVED DESIGNS AND CALCULATIONS.REFER TO "LOT 2, FORT COLLINS BREWERY - SWEETWATER BREWING MAJORAMENDMENT" BY NORTHERN ENGINEERING, FOR RAIN GARDEN SIZING ANDDRAINAGE CALCULATIONS.DESCRIPTIONDATEENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comAPROJECT INFORMATIONSHEET INFORMATION PROJECT PHASE ARCHITECTSEAL ISSUE DATE:PROJECT #:CONSULTANT T - 970.484.0117F - 970.484.0264315 East Mountain AveSuite 100Fort Collins, CO 80524-2913© 2021www.rbbarchitects.comARCHITECTSREVISIONS:100-033CONSTRUCTION DOCUMENTS 10/20/2021BCD54321SWEETWATER BEER GARDEN 1020 EAST LINCOLN AVENUE FORT COLLINS, COLORADO 80524 SWEETWATER BREWING COMPANY NOT FOR CO N S T R U C T I O N REVIEW SE T These drawings are instruments of serviceprovided by Northern Engineering Services,Inc. and are not to be used for any type ofconstruction unless signed and sealed by aProfessional Engineer in the employ ofNorthern Engineering Services, Inc.DESIGNED BY: C. Pape REVIEWED BY: S. Thomas OF 08DRAINAGE EXHIBITC6.00BASINDESIGNATIONMINOR "C2"ABASINAREA (AC)MAJOR "C100"Rational Flow Summary | Developed Basin Flow RatesBASINTOTALAREA(acres)Tc2(min)Tc100(min)C2C100Q2(cfs)Q100(cfs)A10.405.05.00.770.960.883.84B10.425.05.00.911.001.084.16C10.115.05.00.911.000.301.14D10.075.65.60.250.310.050.21100-YEAR INUNDATION AREA08100-YEAR OVERTOP CONTOURPROPOSED RIDGELINELID Summary | Impervious Area TreatedBASINTotal New/ModifiedImpervious NotTreated (sqft)Total New/ModifiedImpervious NotTreated (acres)Total New/ModifiedImperviousTreated (sqft)Total New/ModifiedImperviousTreated (acres)ImperviousTreated/Total NewImperviousLID1 (A1)0.000.0013139.660.300.30/0.38=79%LID2 (C1)3567.480.080.000.00 XXELECTELEVAULTF.O.CABLEVAULTF.O.VAULTF.O.VAULTF.O.ELECELECFDCIRRELECELECBRKRELECBRKREEEEEEEEGGGEE E EFOE CTVGE EEEEGGGGG G FOW W W WEFOFOFOFOEEXXXXSTSTST FND #4 REBARW/RPC, ILLEGIBLEFND #5 REBARW/OPC, PLS 37968EDMONDSFND #5 REBARW/OPC, PLS 37968EDMONDSCTVCTV CTV CTV CTVCTVE EEEEW EEEESSSS100-YR WSEL: 4,943.78PARKING LOT DETENTION100-YR WSEL: 4,943.78PARKING LOT DETENTIONDRAWN BY:SCALE:ISSUED:SWEETWATER BEERGARDENSHEET NO:FORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631ENGINEERNGIEHTRONRN970.221.4158northernengineering.com100-YEAR INUNDATION STAGE STORAGESWEETWATER BEER GARDENC. Pape1in=50ft10-20-20211 OF 1ELEVAREATOTAL(sq. ft.)DEPTH(ft)AVG ENDINC. VOL.(cu. ft.)AVG ENDTOTALVOL.(cu. ft.)AVG ENDTOTALVOL.(AC. ft.)4,942.707N/AN/A00.004,942.803440.1018180.004,942.901,0540.1070880.004,943.002,0780.101572440.014,943.103,4000.102745180.014,943.205,0350.104249430.024,943.306,9420.106041,5470.044,943.409,2140.108132,3600.054,943.5011,2000.101,0243,3840.084,943.6013,1380.101,2194,6030.114,943.7015,2020.101,4186,0210.144,943.7816,6070.081,2737,2940.174,943.8017,1250.023237,6170.17 XXXN. LEMAY AVE.ELECTELEVAULTF.O.CABLEVAULTF.O.VAULTF.O.ELECELECFDCELECELECBRKRELECBRKRGGGGWWG GGGGGGG G G FOFOW W W WFOXXXXXSTSTSTWSSSSSSSSLID1 TO BE TREATEDBY PROPOSED RAIN GARDENLID1LID2LID2 TO BE TREATEDBY EXISTING WATERQUALITY PONDDRAWN BY:SCALE:ISSUED:SWEETWATER BEERGARDENSHEET NO:FORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631ENGINEERNGIEHTRONRN970.221.4158northernengineering.comLID IMPERVIOUS AREA TREATEDSWEETWATER BEER GARDENC. Pape1in=40ft10-20-20211 OF 1LID Summary | Impervious Area TreatedBASINTotal New/ ModifiedImpervious Not Treated(sqft)Total New/ ModifiedImpervious Not Treated(acres)Total New/ ModifiedImpervious Treated(sqft)Total New/ ModifiedImpervious Treated(acres)ImperviousTreated/Total NewImperviousLID1 (A1)0.000.0013139.660.300.30/0.38=79%LID2 (C1)3567.480.080.000.00