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Home My WebLink AboutCOLLEGE EIGHT THIRTY - FDP - FDP160002 - SUBMITTAL DOCUMENTS - ROUND 1 - STORMWATER-RELATED DOCUMENTSDesign Procedure Form: Rain Garden (RG) 11 Sheet 1 of 2 Designer: Andy Reese Company: Northern Engineenn Date: January 13, 2016 Project: College Eight Thirty Location: North Rain Garden 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I, = 100.0 % (100 % if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (I = I,1100) i = 1,000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.40 watershed inches (WQCV= 0.8' 0 91• iS- 1.19' h+ 0.78' i) D) Contributing Watershed Area (including rain garden area) Area = 434 sq ft E) Water Quality Capture Volume (WQCV) Design Volume Vwocv = 14 cu If Vol = (WQCV / 12)' Area F) For Watersheds Outside of the Denver Region, Depth of dS = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWGCV OTRER = 0.0 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume Vwocv USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwocv = 6 in B) Rain Garden Side Slopes (Z = 4 min., honz. dirt per unit vertical) Z = 4,00 ft / ft (Use "0" if rain garden has vertical walls) C) Minnimum Flat Surface Area Au,n = 10 sq ft 0) Actual Flat Surface Area A� = 32 sq h E) Area at Design Depth (Top Surface Area) ATw = 32 sq h F) Rain Garden Total Volume Vr= 16 cu It (VT= ((ATon + Ar .I) / 2) ' Depth) 3. Growing Media Choose One QQ 18" Rain Garden Growing Media �0 Other (Explain): 4. Undertlrain System Choose One r � YES A) Are untlerdrevitletl? ins pro NO B) Undertlrain 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 it) Volume to Drain in 12 Hours Vol,_ = NIA Cu it iii) Office Diameter. 3/8" Minimum C- = N/A in UD-BMP_v3. 02_North Raingardenaxls. RG 1/13/2016, 10:54 AM Design Procedure Form: Rain Garden (RG) Sheet 1 of 2 Designer: Andy Reese Company: Northern Engineering Date: January 13, 2016 Project: College Eight Thirty Location: South Rain Garden 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, to = 100.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Rain (i = 1.1100) i = 1.000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.40 watershed inches (WQCV=0.8' (0.91" i3- 1.19 - i2+0.78' i) D) Contributing Watershed Area (including rain garden area) Area = 434 sq ft E) Water Quality Capture Volume (WQCV) Design Volume Vwocv = 14 cu it Vol = (WQCV / 12)' Area F) For Watersheds Outside of the Denver Region, Depth of de = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWocv OTHER = 0.0 cu if Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume Vwocv USER = cu it (Only If a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwocv = 6 in B) Rain Garden Side Slopes (Z = 4 min., honz. dist per unit vertical) Z = 4.00 1t / it (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AM,,, = 10 sq it D) Actual Flat Surface Area A,,-, = 32 sq If E) Area at Design Depth (Top Surface Area) AT- = 32 sq ft F) Rain Garden Total Volume VT= 16 cu it (Vr ((AT. + Arm) / 2)' Depth) 3, Growing Media C Choose One Q 18" Rain Garden Growing Media 10 Other (Explain): 4. Underdrain System Choose One YES A) Are untlerdrains provided? (D NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage Y = It Volume to the Center of the Orifice ii) Volume to Drain In 12 Hours Vol,, = N/A cu it III) Orrice Diameter, 3/8" Minimum Dr. = N/A in UD-BMP_v3. 02_South Raingarden.xls, RG 1/13/2018. 10 55 AM 0 ' D NORTH RAJ DEN REQUIRED VOLUME: 14 CU. FT. PROVIDED VOLUME: 1 CU. FT. y. y SOUTH RAINCARDEN REQUIRED VOLUME: 14 CU. FT. PROVIDED VOLUME: CU. FT. Q • D 30 0 30 Feet ( IN FEET) 1 Inch =30 fL LEGEND RAIN GARDEN TREATMENTAREA RAN GARDEN PAVER AREA PAVER RUN-ON AREA NORTHERN ■� ENGINEERING 301 N. Ibvras Sliest. Smte 100 PHONES 970.221.4158 FM Cellos, cao wo 80521 www. nalneneN'r.'nli I I I PAVER AREA: 2,076 SF 8,059 SF RUN-ON RUN-ON RATIO =3.9:1 gib 75 ICI DI �,I Uil I 1 I 50%On-Site Treatment by LID Requirement New Impervious Area 0.307 Ac Paver Area 0.048 Ac. Traditional Pavement Area 0.000 Ac. Other Impervious Surfaces (Roofs, Concrete Walks, etc.) 0 260 Ac Required Minimum Impervious Area to 0.154 Ac. be Treab d Paver LID Treatment Paver area 0.048 Ac. Run-on area for Pavers (parking area) 0.000 Ac. Run-on area for Pavers (other -concrete walks, etc.) 0.185 Ac. Impervious Area Treated by LID Pavers 0.233 Ac. Rain Garden Treatment Rain Garden Area 0.001 Ac. Run-on area for Rain Garden 0.020 AL. Impervious Area Treated by Rain 0.021 Ac. Gardens Total Impervious Area Treated 0.254 Ac. Percent of Impervious Area Treated 82.67 % 25% Permeable Pavement Requirement New Pavement Area 2,076 Sq. Ft. Required Minimum Area of Permeable 519 Sq. Ft. Pavement Total Permeable Pavement Area 2076 Sq. Ft. Actual % of Permeable Pavement 100.0 % Provided LID TREATMENT EXHIBIT COLLEGE EIGHT THIRTY FORT COLLINS oanwwe sxe DRAWING COLORADO A. REESE 1'=30' DATE PROECT LID-1 JANUARY 13. 2016 574-006 NORTHERN ENGINEERING LID Conformance Report Date: January 13, 2016 Project: College Eight Thirty Fort Collins, Colorado Attn: Stormwater Staff City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Stormwater Staff: Project No. 574-006 This letter serves to document conformance of the above referenced project with City of Fort Collins Low Impact Development (LID) requirements. In particular, the project is meeting Section 3.1 of the Fort Collins Stormwater Amendments to the Urban Drainage and Flood Control District Criteria Manual, including Section3.1 (a)(1) requiring that no less than 50% of any newly added impervious area be treated using one or more LID techniques and Section 3.1(a)(2) requiring that no less than 25% of all new paving use a permeable pavement technology that is considered an LID technique. Section 3.1(a)(1) The project as a whole is proposing 0.307 acres of new impervious area. This results in a minimum required LID treatment area of 0.154 acres. The project is providing 0.233 acres of impervious area treated by pavers (directly or indirectly), and is treating 0.021 acres of impervious areas using rain gardens. The total project area treated by LID techniques is 0.254 acres, which is 82.67% of the total new impervious area. There is also a small area of roof (0.018 acres) that is being released into a landscaped area within the public ROW that is not being counted towards the requirement but that does treat runoff, making the effective treatment percentage even higher. Section 3.1(a)(2) The project as a whole is proposing 2,076 sf of exposed impervious paving for parking. This results in a minimum required permeable paving area of 519 sf. The project has evaluated various areas for pavers, and has determined that the only appropriate location is the exposed area of paving. The total area of permeable pavers provided by the project is 2,076 sf, which is 100.0% of the total new paving. This greatly exceeds the requirement of 25%. An exhibit has been provided to illustrate the topics outlined. Please feel free to contact me if you have any questions. Sincerely, Andrew Reese Project Engineer I" Y U jAvjU- Nicholas W. Haws, PE LEED Project Manager. AP 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 970.221.4158 www.northernengineering.com