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Home My WebLink AboutDUTCH BROS - FDP190017 - DOCUMENT MARKUPS - ROUND 2 - DRAINAGE REPORTFINAL DRAINAGE REPORT Dutch Bros Coffee Kensington Commons Prepared for: M Squared, LLC 7303 S. Timberline Road Fort Collins, CO 80525 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A Windsor, Colorado 80550 (970) 674-3300 August 21, 2019 Job Number 1380-165-00 1218 W. ASH, STE. A, WINDSOR, COLORADO 80550 TEL. 970.674.3300 – FAX 970.674.3303 August 21, 2019 Mr. Matt Simpson City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage for Dutch Bros Coffee – Kensington Commons Dear Matt, I am pleased to submit for your review and approval, this Final Drainage Report for the Dutch Bros Coffee development. I certify that this report for the drainage design was prepared in accordance with the criteria in the Fort Collins Stormwater Criteria Manual. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, Michael Oberlander, P.E., LEED AP Colorado Professional Engineer No. 34288 7 Basin D is 0.05 acres and is located on the east side of the property. The basin maintains existing conditions and sheets to the curb and gutter of South College Avenue. The water quality capture volume for the site was sized based on a 12-hour drain time and is 775 cf. Please refer to Appendix D for water quality information. The allowable detention release rate is 0.4 cfs; therefore, the required 100-year storage volume for the site is 6,261 cf. The Stormtec system will provide 6,499 cf of total storage. The total is reduced by 460 cf of volume in the bottom 12 inches of isolator row used for water quality. Therefore, the system provides a 6,039 cf of detention storage. There will be some parking lot detention that will pond to an elevation of 5036.2 with a volume of 110 cf. Therefore, the total volume provided for detention is 6,149 cf. Detained flow will be released via a restrictor plate into the existing inlet and existing storm system in College Avenue and ultimately to the Mail Creek and then the Fossil Creek channel. A 10-foot wide emergency overflow spillway is located in the southeast portion of the site. Please refer to Appendix E for detention information. The underground storage system will contain a structure with a design bypass to split flows for treatment and detention. Water quality will be achieved in an isolator row. A second outlet pipe 12 inches above the invert of the isolator row will convey larger storms to the system. The remainder will be detained in the chambers and aggregate volume surrounding and under the chambers. The system proposed for treatment and detention is the Stormtech MC3500 Chamber System and will be located within the Blanket Utility, Drainage and Access Easement. Inspection ports will be provided for inspection and maintenance. Please refer to Appendix E for underground storage information. 5. CONCLUSIONS 5.1 Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual. A separate Erosion Control Report and Plan have been submitted to the City of Fort Collins. Interwest Consulting Group 1218 W. Ash, Suite C Windsor, CO 80550 Inlet Flow Calculation for Nyloplast 2'x3' Road and Highway Grate Project: Dutch Bros Kensington Job Number : 1339-178-00 Calculations by : es Date : 7/23/2019 Objective: to find the number of grates required for area inlets in grassy areas Geometry at inlet : Square Feet Open (A): 2.6813 sf Reduction Factor (F): 50% Grate Flow: Use the orifice equation Qi = C*A*SQRT(2*g*H) to find the ideal inlet capacity.* *See Hydraulic Design Handbook by McGraw-Hill for verificaiton of equation use and C value C = Orifice discharge coefficient= 0.67 A = Orifice area (ft2) - open area of grate g = gravitational constant = 32.2 ft/s2 H = head on grate centroid, ponding depth (feet) Then multiply by the reduction factor for the allowable capacity. QG = Qi * (1-F) DP a DP b Q = 1.8 cfs Q100 Q = 4.9 cfs Q100 H = 0.35 ft H = 0.5 ft A= 2.68 ft2 A= 2.68 ft2 Qi = C*A*SQRT(2*g*H) Qi = C*A*SQRT(2*g*H) = 8.53 cfs = 10.19 cfs QG = Qi * F QG = Qi * F = 4.26 cfs OK = 5.10 cfs OK Grate Open Area and information: WSEL Page1 LOCATION: Dutch Bros. Kensington PROJECT NO: 1380-165-00 COMPUTATIONS BY: es DATE: 7/10/2019 A B C D E F G H I J K WQCV (12 Hr.) WQ Flow (1/2 Q2) Chamber Type Single Chamber Release Rate Through Fabric* Volume in bottom 12" of one Chamber Min Chambers for WQ Flow Through Fabric Chambers Provided Actual Release Rate Thru Fabric Required Storage Volume by FAA Method with Qin=B and Q out=H Min Number of Chambers (Bottom 12") for FAA Release Volume in Bottom 12" of Isolator Rows to be Removed from Detention Volume cf cfs cfs cf (B/D) (G*D) cfs CF (I/E) (G*E) 775 0.7 MC3500 0.036 46 19 10 0.36 152 3 460 * - Single Chamber = 77"x86" = 46 SF FABRIC Fabric Release @ 0.35 gal/min/SF = 16 gal/min/chamber 16 gal/min = 0.036 cfs Isolator Row Volume Check 00 10' 20' SHEET OF DATE: PROJECT #: DRAWN: CHECKED: THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS. 4640 TRUEMAN BLVD HILLIARD, OH 43026 ADVANCED DRAINAGE SYSTEMS, INC. R 2 6 08/06/19 S145040 SDM AMD FORT COLLINS, CO DUTCH BROS DATE DRWN CHKD DESCRIPTION 08/13/19 SDM DAF REVISED PER ENGINEER'S MARK UPS PLACE MINIMUM 17.5' OF ADS GEOSYNTHETICS 315WTM WOVEN GEOTEXTILE OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS 24" CORED END CAP, PART# MC3500IEPP24BC OR MC3500IEPP24BW TYP OF ALL MC-3500 24" BOTTOM CONNECTIONS AND ISOLATOR ROWS PROPOSED LAYOUT 29 STORMTECH MC-3500 CHAMBERS 8 STORMTECH MC-3500 END CAPS 12 STONE ABOVE (in) 15 STONE BELOW (in) 40 % STONE VOID 6,499 INSTALLED SYSTEM VOLUME (CF) (PERIMETER STONE INCLUDED) 1,881 SYSTEM AREA (ft²) 210 SYSTEM PERIMETER (ft) PROPOSED ELEVATIONS 5041.80 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED) 5035.80 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC) 5035.30 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC) 5035.30 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT) 5035.30 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT) 5034.80 TOP OF STONE 5033.80 TOP OF MC-3500 CHAMBER 5031.05 15" MANIFOLD INVERT 5030.22 24" ISOLATOR ROW CONNECTION INVERT 5030.18 15" BOTTOM MANIFOLD INVERT 5030.05 BOTTOM OF MC-3500 CHAMBER 5028.80 UNDERDRAIN INVERT 5028.80 BOTTOM OF STONE NOTES · MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECH SHEET #7 FOR MANIFOLD SIZING GUIDANCE. · DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD COMPONENTS IN THE FIELD. · THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBER COVER REQUIREMENTS ARE MET. · THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED. · THE SITE DESIGN ENGINEER MUST REVIEW THE PROXIMITY OF THE CHAMBERS TO THE BUILDING/STRUCTURE. NO FOUNDATION LOADS SHALL BE TRANSMITTED TO THE CHAMBERS. THE SITE DESIGN ENGINEER MUST CONSIDER EFFECTS OF POSSIBLE SATURATED SOILS ON BEARING CAPACITY OF SOILS AND SEEPAGE INTO BASEMENTS. 15" X 15" ADS N-12 CUSTOM INVERT MANIFOLD INVERT 12.00" ABOVE CHAMBER BASE (SEE NOTES) 6" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAIN (SIZE TBD BY ENGINEER) INSPECTION PORT (TYP 2 PLACES) ISOLATOR ROW (SEE DETAIL / TYP 2PLACES) 15" X 15" ADS N-12 BOTTOM MANIFOLD MAXIMUM OUTLET FLOW 2.7 CFS INVERT 1.5" ABOVE CHAMBER BASE (SEE NOTES) STRUCTURE PER PLAN W/ELEVATED BYPASS MANIFOLD SHOWN AS 36" NYLOPLAST MAXIMUM INLET FLOW 3.5 CFS (24" SUMP MIN) 70 NIWOOD ROAD, SUTIE 3 | ROCKY HLIL | CT | 06067 860-529-8188 |888-892-2694 | WWW.STORMTECH.COM Detention Retention Water Quality 20.25' 22.85' 39.60' 32.44' 75.44' 81.95' CUSTOM CORED END CAP 15" INVERT 12.00" ABOVE CHAMBER BASE