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HomeMy WebLinkAboutCENTRE FOR ADVANCED TECHNOLOGY 23RD, LOT 2 OFFICE BUILDING - PDP/FDP - FDP150007 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTDrainage Letter Report Centre for Advanced Technology, 23th Filing Lot 2 Fort Collins, CO February 25, 2015 Prepared for: CSURF P.O. Box 483 Fort Collins, CO 80522 Prepared by: 200 South College Avenue, Suite 10 Fort Collins, Colorado 80524 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com P This Drainage Report is consciously provided as a PDF. Project Number: 232-033 Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double-sided printing. Drainage Letter Report Page 1 of 3 Drainage Letter Report Date: February 25, 2015 Project: Centre for Advanced Technology Project No. 232-033 23th Filing, Lot 2 Fort Collins, Colorado Attn: Mr. Wes Lamarque City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Dear Wes: This letter serves to address the stormwater impacts of the above referenced project. This project is located within Lot 2 of Centre for Advanced Technology, 23th Filing. This lot was initially Platted as Tract A of the Grove at Fort Collins. Lot 2 is currently comprised of undeveloped grassland owned by CSURF. However, Tract A of the Grove at Fort Collins and Lot 2 of Centre for Advanced Technology was planned as a future development. While the development of this parcel was not a part of The Grove at Fort Collins student housing development, certain assumptions were made in the drainage computations contained within the project. A 90% impervious value was assumed for Tract A, delineated as Basin X within the Final Drainage Report for The Grove at Fort Collins. This basin drains north towards the intersection of Perennial Lane and Botanical Lane. A flared-end-section was constructed to convey flows through a storm sewer under Perennial Lane into the Grove’s water quality pond. Both the storm sewer and water quality pond were sized to accommodate the fully developed future flows from Basin X. (See Appendix C for documentation of Hydrology, Hydraulic and Water Quality calculations performed for The Grove at Fort Collins.) Through design of the Sunshine House – FC 139, Lot 2 was reserved for future development carrying forward the same assumptions used within the Grove at Fort Collins of 90% imperviousness. The off-site basins designated for Lot 2 of within the Sunshine House were divided into four separate basins to better design downstream structures and pathways. Prior to the Sunshine House, Tract A drained from the southeast to the northwest except for a small portion draining off-site to the west (defined as Basin OS4 within the Sunshine House). The remaining three basins (OS1-3) were designed to pass through the Sunshine House project. Basin OS1 was designed to route the majority of stormwater from Lot 2 into Sunshine House Basin A1 and intercept stormwater with an area inlet designated as Design Point a1. Basin OS2 was designed to route stormwater into Sunshine House Basin A2 to be intercepted by a combination inlet designated as Design Point a2. Basin OS3 was designed to route stormwater into Sunshine House Basin B1 to be intercepted by a combination inlet designated as Design Point b1. The Centre for Advanced Technology 23rd Filing, Lot 2 project was designed to closely mimic the anticipated drainage patterns to utilize the previously designed and installed infrastructure. Five major basins were delineated for Lot 2 (Basins A-C, R & OS), each corresponding to an associated storm line in which the basin is routed, except for Basin R which delineates the stormwater routed from the roof and Basin OS which delineates the areas draining off-site. All stormwater from this basin is collected within Centre for Advanced Technology 23th Filing, Lot 2 Drainage Letter Report Page 2 of 3 the Storm Line C. The basins were further divided to allow for calculations at each drainage structure or conveyance element. Basin A is composed of the majority of the northern parking area and conveys stormwater via overland flow and gutter flow. Storm line A was sized to convey all of the stormwater generated from this basin and discharge directly into Basin OS1. Basin B is composed of the remaining portion of the northern parking area and the landscape along the northwest side of the parking area and conveys the stormwater via overland and gutter flow. Storm Line B was sized to convey stormwater generated from Basin B and the upstream basins C and R. The basin was further divided to adequately size the curb cut opening. Basin C is composed of all the drainage area routing stormwater to Storm Line C. Basin C was further divided into three sub basins to account for each conveyance element. Sub basin C1 consist of a small landscape area between the building and northern parking lot, east of the main entrance and conveys stormwater via overland flow to an 8” dome grate. Sub basin C2 is composed of the landscape area located to the south of the building and a portion of the southern roof and conveys stormwater via overland and swale flow to a 10” dome grate located east of the building. Sub basin C3 is composed of the entire southern parking area and the surround walks and conveys stormwater via overland and gutter flow to a combination inlet located in the north corner of the northern parking area. Basin R is composed of the majority of the roof. Basin R was further subdivided into seven sub basins to account for the seven roof leaders draining into Storm Line C. Drainage from these basins is routed off of the roof and into a roof downspout and connected directly to Storm Line C. All of these sub basins and the sub basins within Basin C were included within the calculation for Storm Line C and are shown in Appendix B. Basin OS accounts for all of the areas that is being routed off-site. Basin OS was further subdivided to coincide with the off-site basins defined within Sunshine House, excluding OS 4, which drains into Perennial Lane. Sub basin OS 1 coincides with Sub-basin OS1 of the Sunshine House. This basin is combined with upstream Basins A, B, C & R. The stormwater generated from these basin during the 100- year event is 12.9 cfs, which is less than was designed (13.10 cfs) to be routed through the Sunshine House site. Sub basin OS 2 coincides with Sunshine House and will route stormwater into the constructed parking lot within sunshine house via overland flow. Sub basin OS 3 coincides with Sunshine House and will route stormwater into the constructed parking lot within sunshine house via overland flow. Sub basin OS 4 consist of the landscape area west of the southern parking area and conveys stormwater via overland flow and directly off-site into Perennial Lane. This amount of flow is nominal and will be intercepted by the inlets at the intersection of Perennial Lane and Old Rolland Moore Drive. Historically, a large portion of Lot 2 drained overland and into Perennial Lane. This area is being reduced by this project, resulting in less runoff being routed to the existing inlet. The existing water quality pond is located west of the intersection of Perennial Lane and Botanical Lane. This water quality facility was designed with The Grove at Fort Collins to adequately handle the stormwater from all 3.84 acres of Tract A assuming an overall imperviousness of 90 percent. The overall imperviousness of Lot 1 of the Sunshine House was only 57 percent. The overall imperviousness of Lot 2 is only 52 percent. Both projects are well under the assumed percent imperviousness for Tract A of The Grove. Although stormwater quantity detention is accounted for regionally, stormwater quality mitigation will be addressed by both temporary and permanent Best Management Practices (BMPs). During construction, the Contractor will follow the appropriate and applicable City of Fort Collins standards for erosion and sediment control. A comprehensive Stormwater Management Plan has been prepared for this project, and Centre for Advanced Technology 23th Filing, Lot 2 Drainage Letter Report Page 3 of 3 a copy has been supplied to the Environmental Regulatory Specialist with Fort Collins Utilities. Post construction water quality and erosion control will be achieved by a fully established and stabilized site. All areas disturbed during construction will receive permanent hardscape, landscape, or building structure. Although a portion of Sunshine House, Lot 1 was located within the Spring Creek FEMA regulatory 100- year flood fringe, the Spring Creek FEMA regulatory 100-year flood fringe does not encroach into Lot 2. This flood mapping (Map Number 08069CO987G) was revised May 2, 2012 prior to the construction of Perennial Lane and is attached to this drainage letter. Centre for Advanced Technology 23th Filing, Lot 2 Drainage Letter Report Page 4 of 3 Stormwater quantity detention was addressed with The Grove at Fort Collins, and proved that all of Tract A could develop at 90 percent imperviousness without the need for on-site attenuation. Water quality treatment for the entire Grove subdivision limits occurs within the existing extended detention basin. While the existing pond provides the necessary baseline water quality capture volume for Centre for Advanced Technology, Lot 2, it does not address the recent Low-Impact Development (LID) regulations enacted with Ordinance No. 152, 2012. Therefore, a permeable paver system has been designed with this project and encompasses over 25 percent of the proposed parking area. In addition to the permeable pavers, a bioretention swale has been designed along the northwestern lot line. Through combination of the permeable pavers and bioretention swale, the LID components treats over 50 of the entire project site. Standard Operating Procedures (SOPs) for the LID facilities will be incorporated into the Development Agreement. All detention facilities were designed and constructed to accommodate for an overall development of Tract A at 90 percent imperviousness, which, in combination with Sunshine House, the overall development is well below that anticipation. The Sunshine House development anticipated and designed the infrastructure to convey support Lot 2 being developed at 90 percent imperviousness. Lot 2 is currently proposed well below this assumption, allowing all current conveyance elements to preform within design capacity. Therefore, it is my professional opinion that the proposed improvements to Lot 1 satisfy all applicable stormwater criteria. Please do not hesitate to contact me if you have questions or require additional information. Sincerely, Nicholas W. Haws, PE Vice President Cody N. Snowdon Project Engineer APPENDICES: APPENDIX A – Rational Method Developed Runoff Calculations APPENDIX B – Hydraulic Calculations APPENDIX C – Supporting Documents (The Grove) APPENDIX D – Supporting Documents (Sunshine House) APPENDIX A RATIONAL METHOD DEVELOPED RUNOFF CALCULATIONS Centre for Advanced Technology 23rd Filing - Lot 2 CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: CAT 23rd - Lot 2 Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: C. Snowdon Asphalt ……....……………...……….....…...……………….………………………………….0.. 95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….0.. 50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. A1 29938 0.687 0.358 0.060 0.000 0.000 0.131 0.14 0.68 0.68 0.86 60% B1 2881 0.066 0.000 0.002 0.000 0.000 0.000 0.06 0.17 0.17 0.21 2% B2 10106 0.232 0.111 0.041 0.000 0.000 0.000 0.08 0.67 0.67 0.84 64% C1 1182 0.027 0.000 0.002 0.000 0.000 0.000 0.03 0.21 0.21 0.26 7% C2 10799 0.248 0.000 0.001 0.063 0.000 0.000 0.18 0.36 0.36 0.45 23% C3 9070 0.208 0.023 0.060 0.000 0.000 0.096 0.03 0.58 0.58 0.73 37% Centre for Advanced Technology 23rd Filing - Lot 2 Overland Flow, Time of Concentration: Project: CAT 23rd - Lot 2 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Centre for Advanced Technology 23rd Filing - Lot 2 Rational Method Equation: Project: CAT 23rd - Lot 2 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: a1 A1 0.69 5 5 5 0.68 0.68 0.86 2.85 4.87 9.95 1.34 2.29 5.85 b1 B1 0.07 5 5 5 0.17 0.17 0.21 2.85 4.87 9.95 0.03 0.05 0.14 b2 B2 0.23 6 6 5 0.67 0.67 0.84 2.76 4.72 9.95 0.43 0.74 1.94 c1 C1 0.03 6 6 6 0.21 0.21 0.26 2.67 4.56 9.63 0.02 0.03 0.07 c2 C2 0.25 5 5 5 0.36 0.36 0.45 2.85 4.87 9.95 0.25 0.43 1.11 c3 C3 0.21 9 9 6 0.58 0.58 0.73 2.35 4.02 9.31 0.28 0.49 1.41 r1 R1 0.02 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.05 0.09 0.19 r2 R2 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.07 0.12 0.27 r3 R3 0.02 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.06 0.10 0.22 r4 R4 0.02 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.07 0.11 0.24 r5 R5 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.09 0.15 0.31 r6 R6 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.09 0.16 0.34 r7 R7 0.05 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.13 0.22 0.48 os1 OS1 0.10 5 5 5 0.64 0.64 0.80 2.85 4.87 9.95 0.18 0.30 0.77 os2 OS2 0.03 5 5 5 0.89 0.89 1.00 2.85 4.87 9.95 0.09 0.15 0.34 os3 OS3 0.03 5 5 5 0.15 0.15 0.19 2.85 4.87 9.95 0.01 0.02 0.06 os4 OS4 0.05 5 5 5 0.16 0.16 0.20 2.85 4.87 9.95 0.02 0.04 0.10 DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) C. Snowdon February 25, 2015 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Area, A (acres) Intensity, i2 (in/hr) 100-yr Centre for Advanced Technology 23rd Filing - Lot 2 CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: CAT 23rd - Lot 2 Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: C. Snowdon Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: February 25, 2015 Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Design Point Basin IDs Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. os1 OS1, A1, B1-2, B1-3 & R1-7 77128 1.77 0.54 0.17 0.27 0.00 0.23 0.56 0.63 0.63 0.78 53% b1 B1-2, B1-3 & R1-7 42976 0.99 0.13 0.11 0.27 0.00 0.10 0.38 0.59 0.59 0.73 48% COMBINED DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS **Soil Classification of site is Sandy Loam** 10-year Cf = 1.00 Centre for Advanced Technology 23rd Filing - Lot 2 Overland Flow, Time of Concentration: Project: CAT 23rd - Lot 2 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Centre for Advanced Technology 23rd Filing - Lot 2 Rational Method Equation: Project: CAT 23rd - Lot 2 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: os1 OS1, A1, B1-2, B1-3 & R1-7 1.77 10 10 6 0.63 0.63 0.78 2.26 3.86 9.31 2.5 4.3 12.9 b1 B1-2, B1-3 & R1-7 0.99 9 9 7 0.59 0.59 0.73 2.30 3.93 8.80 1.3 2.3 6.4 COMBINED DEVELOPED RUNOFF COMPUTATIONS C. Snowdon February 25, 2015 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) Flow, Q10 (cfs) Flow, Q100 (cfs) C2 C 10 C100 Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Q = C f ( C )( i )( A ) Page 6 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\Comb-Direct-Runoff Centre for Advanced Technology 23rd Filing - Lot 2 DESIGN POINT BASIN ID TOTAL AREA (acres) C10 C100 10-yr Tc (min) 100-yr Tc (min) Q10 (cfs) Q100 (cfs) a1 A1 0.69 0.68 0.86 5.0 5.0 2.3 5.9 b1 B1 0.07 0.17 0.21 5.4 5.2 0.1 0.1 b2 B2 0.23 0.67 0.84 5.9 5.0 0.7 1.9 c1 C1 0.03 0.21 0.26 6.2 5.9 0.0 0.1 c2 C2 0.25 0.36 0.45 5.0 5.0 0.4 1.1 c3 C3 0.21 0.58 0.73 8.8 6.5 0.5 1.4 r1 R1 0.02 0.95 1.00 5.0 5.0 0.1 0.2 r2 R2 0.03 0.95 1.00 5.0 5.0 0.1 0.3 r3 R3 0.02 0.95 1.00 5.0 5.0 0.1 0.2 r4 R4 0.02 0.95 1.00 5.0 5.0 0.1 0.2 r5 R5 0.03 0.95 1.00 5.0 5.0 0.1 0.3 r6 R6 0.03 0.95 1.00 5.0 5.0 0.2 0.3 r7 R7 0.05 0.95 1.00 5.0 5.0 0.2 0.5 os1 OS1 0.10 0.64 0.80 5.0 5.0 0.3 0.8 os2 OS2 0.03 0.89 1.00 5.0 5.0 0.1 0.3 os3 OS3 0.03 0.15 0.19 5.0 5.0 0.0 0.1 os4 OS4 0.05 0.16 0.20 5.0 5.0 0.0 0.1 DESIGN POINT BASIN ID TOTAL AREA (acres) C10 C100 10-yr Tc (min) 100-yr Tc (min) Q10 (cfs) Q100 (cfs) os1 OS1, A1, B1-2, B1-3 & R1-7 1.77 0.63 0.78 9.8 6.0 4.3 12.9 b1 B1-2, APPENDIX B HYDRAULIC CALCULATIONS 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 2' Curb Inlet Diagonal Grate Inlet Capacity Chart High Hood Setting (8.47" Curb Setting) Mid Hood Setting (6.47" Curb Setting) Low Hood Setting (4.47" Curb Setting) 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 10" Dome Grate Inlet Capacity Chart 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 8" Dome Grate Inlet Capacity Chart 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 2' Steel Bar / MAG Grate Inlet Capacity Chart Weir Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Feb 25 2015 Curb Cut DP OS1 Rectangular Weir Crest = Sharp Bottom Length (ft) = 4.00 Total Depth (ft) = 4.00 Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 0.80 Highlighted Depth (ft) = 0.15 Q (cfs) = 0.800 Area (sqft) = 0.61 Velocity (ft/s) = 1.31 Top Width (ft) = 4.00 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Depth (ft) Curb Cut DP OS1 Depth (ft) -1.00 -1.00 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 Weir W.S. Length (ft) Weir Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Feb 25 2015 Curb Cut DP b2 Rectangular Weir Crest = Sharp Bottom Length (ft) = 4.00 Total Depth (ft) = 4.00 Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 1.90 Highlighted Depth (ft) = 0.27 Q (cfs) = 1.900 Area (sqft) = 1.09 Velocity (ft/s) = 1.74 Top Width (ft) = 4.00 0 .5 1 1.5 2 2.5 3 3.5 4 4.5 5 Depth (ft) Curb Cut DP b2 Depth (ft) -1.00 -1.00 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 Weir W.S. Length (ft) Circular D or Da, Pipe Diameter (ft) H or Ha, Culvert Height (ft) W, Culvert Width (ft) Yt/D Q/D1.5 Q/D2.5 Yt/H Q/WH0.5 Storm Line A 6.40 1.00 0.40 0.40 6.40 6.40 N/A N/A 1.30 6.40 1.28 2.86 Type L 5.00 3.00 2.0 Storm Line B 5.90 1.00 0.40 0.40 5.90 5.90 N/A N/A 1.95 5.90 1.18 3.80 Type L 5.00 3.00 2.0 Storm Line C 6.40 1.00 0.40 0.40 6.40 6.40 N/A N/A 1.30 6.40 1.28 2.86 Type L 5.00 3.00 2.0 Expansion Factor 1/(2tanq) (From Figure MD-23 or MD-24) Date: January 29, 2014 INPUTOUTPUT CALCULATE Yt, Tailwater Depth (ft) Project: Sunshine House - FC 139 Urban Drainage pg MD-107 Culvert Parameters Storm Line/Culvert Label Design Discharge (cfs) L= 1/(2tanq)* [At/Yt)-W] (ft) At=Q/V (ft) Spec Length of Riprap (ft) Box Culvert By: CNS CALCULATIONS FOR RIPRAP PROTECTION Circular Pipe (Figure MD-21) Rectangular Pipe (Figure MD-22) Spec Page 2 of 3 Location Pipe Diameter (Inches) Ordinary Riprap Type Riprap Length (ft) Riprap Width (ft) Riprap Depth (ft) Storm Line A 12 Type L 5.0 3.0 2.0 Storm Line B 12 Type L 5.0 3.0 2.0 Storm Line C 12 Type L 5.0 3.0 2.0 Page 3 of 3 APPENDIX C SUPPORTING DOCUMENTS (THE GROVE) Final Drainage and Erosion Control Report CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: The Grove Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: A. Reese Asphalt ……....……………...……….....…...……………….…………………………………..0.95 100 Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90 Gravel ……….…………………….….…………………………..……………………………….0.. 50 40 Roofs …….…….………………..……………….…………………………………………….. 0.95 90 Pavers…………………………...………………..…………………………………………….. 0.40 22 Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0 Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. A1 48,362 1.11 0.00 0.00 0.00 0.00 1.11 0.25 0.25 0.31 0.0 A2 25,167 0.58 0.41 0.05 0.06 0.00 0.06 0.88 0.88 1.00 87.6 A3 19,677 0.45 0.00 0.00 0.00 0.00 0.45 0.25 0.25 0.31 0.0 A4 58,269 1.34 0.46 0.10 0.22 0.00 0.56 0.66 0.66 0.82 56.0 B1 72,453 1.66 0.68 0.33 0.14 0.00 0.51 0.74 0.74 0.92 66.8 B2a 201,089 4.62 1.42 0.57 0.46 0.00 2.16 0.62 0.62 0.78 51.0 B2b 19,389 0.45 0.00 0.00 0.11 0.00 0.33 0.42 0.42 0.53 22.4 B2c 71,476 1.64 0.00 0.05 0.35 0.00 1.24 0.42 0.42 0.52 21.8 C1 27,895 0.64 0.29 0.23 0.00 0.00 0.12 0.82 0.82 1.00 77.8 C2 60,895 1.40 0.28 0.18 0.36 0.00 0.58 0.66 0.66 0.83 55.0 Final Drainage and Erosion Control Report Overland Flow, Time of Concentration: Project: The Grove Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Final Drainage and Erosion Control Report Overland Flow, Time of Concentration: Project: The Grove Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = T i + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S ½ Velocity (Swale Flow), V = 15·S ½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Additional Gutter Flow Additional Swale Flow Tc Calculated at Upstream Design Point A. Reese January 6, 2012 Time of Concentration (Equation RO-4) 3 1 1 . 87 1 . 1 * S Ti C Cf L  Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Final Drainage and Erosion Control Report Rational Method Equation: Project: The Grove Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: A1 A1 1.11 11 11 11 0.25 0.25 0.31 2.13 3.63 7.42 0.6 1.0 2.6 A2 A2 0.58 5 5 5 0.88 0.88 1.00 2.85 4.87 9.95 1.4 2.5 5.7 A3 A3 0.45 5 5 5 0.25 0.25 0.31 2.85 4.87 9.95 0.3 0.5 1.4 A4 A4 1.34 5 5 5 0.66 0.66 0.82 2.85 4.87 9.95 2.5 4.3 11.0 B1 B1 1.66 10 10 9 0.74 0.74 0.92 2.26 3.86 8.03 2.8 4.7 12.3 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) A. Reese January 6, 2012 Q C f C i A B1 B1 1.66 10 10 9 0.74 0.74 0.92 2.26 3.86 8.03 2.8 4.7 12.3 B2a B2a 4.62 10 10 10 0.62 0.62 0.78 2.26 3.86 7.88 6.5 11.1 28.3 B2b B2b 0.45 5 5 5 0.42 0.42 0.53 2.85 4.87 9.95 0.5 0.9 2.3 B2c B2c 1.64 9 9 8 0.42 0.42 0.52 2.35 4.02 8.38 1.6 2.8 7.2 C1 C1 0.64 5 5 5 0.82 0.82 1.00 2.85 4.87 9.95 1.5 2.6 6.4 C2 C2 1.40 5 5 5 0.66 0.66 0.83 2.85 4.87 9.95 2.6 4.5 11.5 C3 C3 2.06 5 5 5 0.75 0.75 0.94 2.85 4.87 9.95 4.4 7.5 19.2 C4 C4 1.23 5 5 5 0.74 0.74 0.93 2.85 4.87 9.95 2.6 4.5 11.4 D1 D1 0.93 5 5 5 0.79 0.79 0.99 2.85 4.87 9.95 2.1 3.6 9.2 Final Drainage and Erosion Control Report Rational Method Equation: Project: The Grove Calculations By: Date: From Section 3.2.1 of the CFCSDDC COMBINED RUNOFF COMPUTATIONS A. Reese January 6, 2012 Q C f C i A Rainfall Intensity: A1 A1-A4, B1, B2, C1-C4, D1, D2, X 22.71 27 27 27 0.68 0.68 0.85 58.92 1.39 2.37 4.83 21.3 36.4 92.9 C4 A1-A4, B1, B2, C4 10.99 19 19 19 0.62 0.62 0.77 50.51 1.68 2.86 5.84 11.4 19.4 49.2 Flow, Q100 (cfs) Composite % Imperv. C2 C 10 C100 Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) Flow, Q10 (cfs) D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\Combined Runoff Final Drainage and Erosion Control Report DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr Tc (min) 100-yr Tc (min) Q2 (cfs) Q10 (cfs) Q100 (cfs) A1 A1 1.11 0.25 0.31 11.3 11.1 0.6 1.0 2.6 A2 A2 0.58 0.88 1.00 5.0 5.0 1.4 2.5 5.7 A3 A3 0.45 0.25 0.31 5.0 5.0 0.3 0.5 1.4 A4 A4 1.34 0.66 0.82 5.0 5.0 2.5 4.3 11.0 B1 B1 1.66 0.74 0.92 9.7 9.4 2.8 4.7 12.3 B2a B2a 4.62 0.62 0.78 10.0 9.7 6.5 11.1 28.3 B2b B2b 0.45 0.42 0.53 5.0 5.0 0.5 0.9 2.3 B2c B2c 1.64 0.42 0.52 8.9 8.4 1.6 2.8 7.2 C1 C1 0.64 0.82 1.00 5.3 5.1 1.5 2.6 6.4 C2 C2 1.40 0.66 0.83 5.0 5.0 2.6 4.5 11.5 C3 C3 2.06 0.75 0.94 5.0 5.0 4.4 7.5 19.2 C4 C4 1.23 0.74 0.93 5.0 5.0 2.6 4.5 11.4 D1 D1 0.93 0.79 0.99 5.0 5.0 2.1 3.6 9.2 D2 D2 0.75 0.78 0.98 5.0 5.0 1.7 2.9 7.4 X X 3.84 0.88 1.00 19.9 18.5 5.5 9.4 22.4 CH1 CH1 0.04 0.80 1.00 5.0 5.0 0.1 0.2 0.4 CH2 CH2 0.16 0.41 0.51 5.0 5.0 0.2 0.3 0.8 OS1 OS1 1.00 0.25 0.31 9.9 9.2 0.6 1.0 2.5 OS2 OS2 1.74 0.25 0.31 14.1 13.1 0.8 1.4 3.8 OS3 OS3 15.42 0.25 0.31 75.1 70.6 2.7 4.6 12.4 OS4 OS4 0.66 0.88 1.00 12.3 11.8 1.2 2.0 4.8 OS5 OS5 0.23 0.86 1.00 5.0 5.0 0.6 1.0 2.3 OS6 OS6 0.29 0.80 1.00 5.0 5.0 0.7 1.1 2.9 A1 A1-A4, B1, B2, C1-C4, D1, D2, X 22.71 0.68 0.85 26.5 26.5 21.3 36.4 92.9 C4 A1-A4, B1, B2, C4 10.99 0.62 0.77 18.5 18.5 11.4 19.4 49.2 D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\Summary Table Project Tittle Date: Project Number Calcs By: Client Pond Designation 1 WQCV = Watershed inches of Runoff (inches) 58.92% a = Runoff Volume Reduction (constant) i = Total imperviouness Ratio (i = Iwq/100) 0.233 in The Grove at Fort Collins January 6, 2012 502-001 A. Reese Campus Crest Water Quality Pond Drain Time a = i = WQCV = 0.233 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 WQCV (watershed inches) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV a 0.91 i 3  1 . 19 i 2  0 . 78 i WQCV a 0.91 i 3  1 . 19 i 2  0 . 78 i 40 hr A = 22.71 ac V = 0.53 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 1.2 = 20% Additional Volume (Sediment Accumulation) Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event Total Imperviousness Ratio (i = Iwq /100) * * 1 . 2 12 V WQCV A Project Tittle Date: Project Number Calcs By: Client Pond Designation Invert Elevation Water Quality Volume 100-yr Detention Volume Total Pond Volume Min Sc D = Depth between contours (ft.) A1 = Surface Area lower contour (ft2) t A2 = Surface Area upper contour (ft2) Area/Row No. of Rows 4993.80 1.74 -0.01 0.00 0.00 0.0000 4994.00 157.31 0.20 11.71 11.70 0.0003 4994.20 1073.02 0.20 109.41 121.11 0.0028 4994.40 2316.96 0.20 331.12 452.23 0.0104 4994.60 3908.20 0.20 615.62 1067.85 0.0245 4994.80 4739.86 0.20 863.47 1931.32 0.0443 4995.00 5041.49 0.20 977.98 2909.30 0.0668 4995.20 5356.00 0.20 1039.59 3948.89 0.0907 4995.40 5689.67 0.20 1104.40 5053.29 0.1160 4995.60 6042.26 0.20 1173.02 6226.31 0.1429 4995.80 6413.53 0.20 1245.39 7471.70 0.1715 4996.00 6803.15 0.20 1321.48 8793.18 0.2019 4996.20 7252.55 0.20 1405.33 10198.51 0.2341 4996.40 7667.56 0.20 1491.82 11690.33 0.2684 4996.60 8104.86 0.20 1577.04 13267.37 0.3046 4996.80 8558.13 0.20 1666.09 14933.46 0.3428 Water Quality Pond Volume Elevation (ft) Circular Perforation Sizing Dia (in.) 3 0.00 ac-ft Water Quality Pond 0.6 11 0.53 ac-ft 4993.81 ft n 1/4 Depth (ft) Surface Area (ft 2 ) Total Outlet Area 6.60 sq. in. The Grove at Fort Collins January 6, 2012 502-001 A. Reese Campus Crest 0.53 ac-ft Total Vol. (ac-ft) Total Vol. (ft 3 APPENDIX D SUPPORTING DOCUMENTS (SUNSHINE HOUSE) Drainage Letter Report Centre for Advanced Technology, 28th Filing Sunshine House – FC 139 Fort Collins, CO January 29, 2014 Prepared for: CSURF P.O. Box 483 Fort Collins, CO 80522 Prepared by: 200 South College Avenue, Suite 10 Fort Collins, Colorado 80524 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com 3 This Drainage Report is consciously provided as a PDF. Project Number: 232-023 Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double-sided printing. Drainage Letter Report Date: January 29, 2014 Project: Centre for Advanced Technology, 28th Filing Project No. 232-023 Sunshine House – FC 139 Fort Collins, Colorado Attn: Mr. Wes Lamarque City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Dear Wes: This letter serves to address the stormwater impacts of the above referenced project. The project is located within Tract A of The Grove at Fort Collins. Tract A is currently comprised of undeveloped grassland owned by CSURF. However, Tract A was planned as a future development in accordance with the ODP of record (E zoning district). While the development of this parcel was not a part of The Grove at Fort Collins student housing development, certain assumptions were made in the drainage computations contained within the project. A 90% impervious value was assumed for Tract A, delineated as Basin X within the Final Drainage Report for The Grove at Fort Collins. This basin drains north towards the intersection of Perennial Lane and the old Rolland Moore Drive (to be renamed as Botanical Lane). A flared-end-section was constructed to convey flows through a storm sewer under Perennial Lane into the Grove’s water quality pond. Both the storm sewer and water quality pond were sized to accommodate the fully developed future flows from Basin X. (See Appendix C for documentation of Hydrology, Hydraulic and Water Quality calculations performed for The Grove at Fort Collins.) Sunshine House – FC 139 is proposing to subdivide Tract A into one Lot and one Tract. The proposed improvements are planned to occur within the northern half of the original Tract A (proposed Lot 1). The southern half of Tract A of The Grove at Fort Collins will be replatted as Tract A of Sunshine House – FC 139, and will remain undeveloped. Due to the governing ODP of record, the remainder of Tract A will be reserved for future development carrying forward the same assumptions used with The Grove at Fort Collins. The off-site basins within Tract A of Sunshine House – FC 139 have been divided into four separate basins to better define the drainage calculations. Currently, Tract A drains from the southeast to the northwest except for a small portion draining off-site to the west (Basin OS4). Until the southern portion is developed, the current drainage patterns have been accounted for within the improvements proposed for the Sunshine House – FC 139. Upon full build-out of Tract A, the drainage patterns within Basins OS 1-3 will need to be rerouted to discharge at the northwest corner of the site into proposed Basin A1. Four major basins were delineated for Lot 1 (Basins A-D), each corresponding to an associated storm line in which the basin is routed, except for Basin D. The basins were further divided to allow for calculations at each drainage structure or conveyance element. Centre for Advanced Technology, 28th Filing Sunshine House – FC 139 Drainage Letter Report Page 3 of 3 Basin A is composed of the western portion of Lot 1 and conveys stormwater via overland, swale, gutter and pipe flow. Storm Line A was sized to allow for all of the drainage from Tract A (Basins OS1-OS2) to be routed through the site upon full build-out at 90 percent imperviousness. The basin was further divided to account for each conveyance element and calculations are shown in Appendices A and B. Basin B is composed of the eastern portion of Lot 1 and conveys stormwater via overland, swale, gutter and pipe flow. Storm Line B was sized to allow the existing portion of Tract A (Basin OS3) to be routed through the site in current conditions. Upon full build-out of Tract A, all drainage patterns within Basin OS3 will need to be rerouted to discharge into Basin A1. Basin B was further divided to account for each conveyance element and calculations are shown in Appendices A and B. Basin C is composed of a small portion of the roof and conveys water via overland and pipe flow. Storm line C was sized to drain this roof area through the three associated roof leaders. Basin D consists of the landscape area on the north side of the proposed building and a portion of the proposed building on the east side. All other proposed basins drain into this area and stormwater is conveyed via overland and swale flow. All of the drainage from the site and Basin D is discharged into an existing storm sewer line located within the northwestern corner of the project. This storm sewer (Storm Line 4) was designed to convey all stormwater from Tract A and discharges directly into an existing water quality pond. The existing water quality pond is located west of the intersection of Perennial Lane and old Rolland Moore Drive (to be renamed as Botanical Lane). This water quality facility was designed with The Grove at Fort Collins to adequately handle the stormwater from all 3.84 acres of Tract A assuming an overall imperviousness of 90 percent. Assuming the remaining 1.89 acres of Tract A to be 90 percent impervious, the overall imperviousness of both Lot 1 and Tract A of Sunshine House – FC 139 is only 57 percent, which is well below the 90 percent allocated for the entire basin. Although stormwater quantity detention is accounted for regionally, stormwater quality mitigation will be addressed by both temporary and permanent Best Management Practices (BMPs). During construction, the Contractor will follow the appropriate and applicable City of Fort Collins standards for erosion and sediment control. A comprehensive Stormwater Management Plan has been prepared for this project, and a copy has been supplied to the Environmental Regulatory Specialist with Fort Collins Utilities. Post construction water quality and erosion control will be achieved by a fully established and stabilized site. All areas disturbed during construction will receive permanent hardscape, landscape, or building structure. A small portion of the project site at the northwest corner of the property is located in the Spring Creek FEMA regulatory 100-year flood fridge. This flood mapping (Map Number 08069CO987G) was revised May 2, 2012 prior to the construction of Perennial Lane. Since a small portion of the development falls within a 100-year high risk flood fringe, a Floodplain Use Permit (FUP) shall be obtained prior to commencing with any construction within this area. The only proposed improvements within the 100-year high risk flood fringe consist of site work (sidewalk, grading landscaping, etc.). As such, this project seeks to obtain a FUP with the initial Development Construction Permit (DCP), which would then cover all work to take place within the floodplain. Through the use of the current effective floodplain model obtained from the City Stormwater Staff, an approximate 500-year flood elevation was calculated. The lowest floor elevation of the proposed critical facility has been set over 5 feet above this anticipated 500-year Base Flood Elevation (BFE). Nonetheless, an official 500-year floodplain is yet to be established and the risk potential is acknowledged. However, the Applicant feels that the risk is minimal. The elevated site and roadways are expected to remain above 500-year floodplain mapping, and 100-year dry land access is provided. Centre for Advanced Technology, 28th Filing Sunshine House – FC 139 Drainage Letter Report Page 4 of 3 Stormwater quantity detention was addressed with The Grove at Fort Collins, and proved that all of Tract A could develop at 90 percent imperviousness without the need for on-site attenuation. Water quality treatment for the entire Grove subdivision limits occurs within the existing extended detention basin. While the existing pond provides the necessary baseline water quality capture volume for Sunshine House – FC 139, it does not address the recent Low-Impact Development (LID) regulations enacted with Ordinance No. 152, 2012. Therefore, a permeable paver system has been designed with this project and encompasses over 25 percent of the proposed parking area. This LID component also treats roughly 50 of the new impervious surfaces, including the entire parking lot itself, which is the primary area of concern from a pollutant source standpoint. In analyzing Lot 1 and Tract A of Sunshine House – FC 139, the entire area was master planned to have an imperviousness of 90 percent, whereas the current proposal results in an imperviousness of only 57 percent. All drainage structures and facilities, including regional water quality, were designed and constructed to adequately handle the full build-out of both Lot 1 and Tract A. Lot 1 is currently being designed to allow for drainage from Tract A at full build-out to be routed through the project site. The proposed development complies with applicable drainage master plans governing the site, primarily that of Spring Creek, Centre for Advanced Technology, and The Grove at Fort Collins. Standard Operating Procedures (SOPs) for the LID facilities will be incorporated into the Development Agreement. Furthermore, the project is designed in accordance to the governing floodplain regulations contained within Chapter 10 of the City Code, and the Floodplain Use Permit shall ensure that construction remains compliant with Chapter 10. Therefore, it is my professional opinion that the proposed improvements to Lot 1 satisfy all applicable stormwater criteria. Please do not hesitate to contact me if you have questions or require additional information. Sincerely, Nicholas W. Haws, PE Vice President Cody N. Snowdon Project Engineer APPENDICES: APPENDIX A – Rational Method Developed Runoff Calculations APPENDIX B – Hydraulic Calculations APPENDIX C – Supporting Documents APPENDIX A RATIONAL METHOD DEVELOPED RUNOFF CALCULATIONS Sunshine House - FC 139 CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Sunshine House Daycare - #139 Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: C. Snowdon Asphalt ……....……………...……….....…...……………….………………………………….0.. 95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….0.. 50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. A1 3477 0.08 0.00 0.00 0.00 0.00 0.00 0.08 0.15 0.15 0.19 0% A2 8572 0.20 0.06 0.03 0.00 0.00 0.07 0.04 0.59 0.59 0.74 42% A3 3492 0.08 0.00 0.01 0.02 0.00 0.00 0.05 0.46 0.46 0.58 35% A4 1391 0.03 0.00 0.00 0.03 0.00 0.00 0.00 0.95 0.95 1.00 90% A5 1382 0.03 0.00 0.00 0.03 0.00 0.00 0.00 0.95 0.95 1.00 90% B1 17410 0.40 0.20 0.03 0.00 0.00 0.03 0.14 0.63 0.63 0.78 57% Sunshine House - FC 139 Overland Flow, Time of Concentration: Project: Sunshine House Daycare - #139 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Sunshine House - FC 139 Rational Method Equation: Project: Sunshine House Daycare - #139 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: a1 A1 0.08 5 5 5 0.15 0.15 0.19 2.85 4.87 9.95 0.03 0.06 0.15 a2 A2 0.20 5 5 5 0.59 0.59 0.74 2.85 4.87 9.95 0.33 0.57 1.45 a3 A3 0.08 5 5 5 0.46 0.46 0.58 2.85 4.87 9.95 0.11 0.18 0.46 a4 A4 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.09 0.15 0.32 a5 A5 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.09 0.15 0.32 b1 B1 0.40 5 5 5 0.63 0.63 0.78 2.85 4.87 9.95 0.71 1.22 3.11 b2 B2 0.09 5 5 5 0.54 0.54 0.67 2.85 4.87 9.95 0.14 0.23 0.59 b3 B3 0.15 6 6 5 0.37 0.37 0.46 2.76 4.72 9.95 0.15 0.26 0.68 b4 B4 0.03 6 6 5 0.95 0.95 1.00 2.76 4.72 9.95 0.08 0.14 0.31 c1 C1 0.03 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.09 0.15 0.32 d1 D1 0.83 7 7 7 0.20 0.20 0.25 2.52 4.31 9.06 0.41 0.70 1.84 os1 OS1 1.27 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 3.16 5.39 12.66 os2 OS2 0.24 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 0.60 1.02 2.40 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) DEVELOPED RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) C. Snowdon December 20, 2013 Q C f C i A os2 OS2 0.24 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 0.60 1.02 2.40 Sunshine House - FC 139 CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: Engines & Energy Conversion Lab Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: C. Snowdon Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Design Point Basin IDs Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Pavers (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. a1 OS1-3 & A1 (Ultimate Design) 82216 1.89 1.63 0.00 0.00 0.00 0.00 0.12 0.83 0.83 1.00 86% b1 OS3 & B1 (Existing Conditions) 30193 0.69 0.20 0.03 0.00 0.00 0.03 0.17 0.37 0.37 0.46 33% COMBINED DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Sunshine House - FC 139 Overland Flow, Time of Concentration: Project: Sunshine House Daycare - #139 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Sunshine House - FC 139 Rational Method Equation: Project: Sunshine House Daycare - #139 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: a1 OS1-3 & A1 (Ultimate Design) 1.89 14 14 13 0.83 0.83 1.00 1.92 3.29 6.92 3.0 5.1 13.1 b1 OS3 & B1 (Existing Conditions) 0.69 15 15 14 0.37 0.37 0.46 1.90 3.24 6.82 0.5 0.8 2.2 C2 C 10 C100 Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) COMBINED DEVELOPED RUNOFF COMPUTATIONS C. Snowdon December 20, 2013 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) Flow, Q10 (cfs) Flow, Q100 (cfs) Q C f C i A Page 6 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\Comb-Direct-Runoff Sunshine House - FC 139 DESIGN POINT BASIN ID TOTAL AREA (acres) C10 C100 10-yr Tc (min) 100-yr Tc (min) Q10 (cfs) Q100 (cfs) a1 A1 0.08 0.15 0.19 5.0 5.0 0.1 0.1 a2 A2 0.20 0.59 0.74 5.0 5.0 0.6 1.5 a3 A3 0.08 0.46 0.58 5.0 5.0 0.2 0.5 a4 A4 0.03 0.95 1.00 5.0 5.0 0.1 0.3 a5 A5 0.03 0.95 1.00 5.0 5.0 0.1 0.3 b1 B1 0.40 0.63 0.78 5.0 5.0 1.2 3.1 b2 B2 0.09 0.54 0.67 5.0 5.0 0.2 0.6 b3 B3 0.15 0.37 0.46 5.7 5.3 0.3 0.7 b4 B4 0.03 0.95 1.00 5.5 5.1 0.1 0.3 c1 C1 0.03 0.95 1.00 5.0 5.0 0.1 0.3 d1 D1 0.83 0.20 0.25 7.1 6.8 0.7 1.8 os1 OS1 1.27 0.87 1.00 5.0 5.0 5.4 12.7 os2 OS2 0.24 0.87 1.00 5.0 5.0 1.0 2.4 os3 OS3 0.29 0.87 1.00 11.3 10.9 0.9 2.2 os4 OS4 0.08 0.87 1.00 5.0 5.0 0.4 0.8 DESIGN POINT BASIN ID TOTAL AREA (acres) C10 C100 10-yr Tc (min) 100-yr Tc (min) Q10 (cfs) Q100 (cfs) a1 OS1-3 & A1 (Ultimate Design) 1.89 0.83 1.00 14.1 13.2 5.1 13.1 b1 OS3 & B1 (Existing APPENDIX B HYDRAULIC CALCULATIONS X VAULT ELEC CONTROL IRR CONTROL IRR CONTROL CONTROL IRR IRR X X X X X X ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / PERENNIAL LANE 100-YEAR FEMA FLOODPLAIN BOUNDARY BOTANICAL LANE OS1 OS2 OS3 A1 A2 B1 A3 G X X X X X X G G G G G G G G G G G G G G G G G X X ST ST ST SS SS T T T T T T T T T T T T T T T T T / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / UD AD AD AD AD AD X X X X X X X X X ST 19906 - 5000.4 NAVD 88 19776 - 4998.7 NAVD 88 20390 - 5001.7 NAVD 88 100-YEAR FEMA FLOODPLAIN BOUNDARY 100-YEAR FEMA FLOODPLAIN BOUNDARY 100-YEAR FEMA FLOODPLAIN BOUNDARY 100-YEAR FEMA FLOODWAY BOUNDARY 100-YEAR FEMA FLOODWAY BOUNDARY 100-YEAR FEMA FLOODPLAIN BOUNDARY EXISTING STORM SEWER EXISTING STORM SEWER PROPOSED STORM SEWER CENTRE AVENUE PERENNIAL LANE NATIVE PLANT WAY LOT 1 BOTANICAL LANE GILGALAD WAY FFE=3.50 Sheet Of 17 Sheets 200 S���� C������ A�����, S���� 010 F��� C������, C������� 80524 E N G I N E E R I N G � � � � � � �� PHONE: 970.221.4158 FAX: 970.221.4159 ���.�������������������.��� SUNSHINE HOUSE - FC 139 CENTRE FOR ADVANCED TECHNOLOGY 23 FILING 01.28.14 C4.01 FLOODPLAIN EXHIBIT NOTES: FIELD SURVEY BY: BENCHMARKS: 20554 NORTH GRAPHIC SCALE: LEGEND: / / / / / / / / / / / / / / / / / / / / / / / / / / / / UD FOR STORMWATER REVIEW ONLY NOT FOR CONSTRUCTION CALL UTILITY NOTIFICATION CENTER OF COLORADO K��� ����'� �����. C��� ������ ��� ���. R FEMA REFERENCE: A4 D1 B2 B3 B4 C1 OS4 A5 a1 a2 a3 a4 a5 d1 os1 os2 os3 os4 b1 b3 b4 c1 b2 NATIVE PLANT WAY EXISTING WATER QUALITY POND LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOD LOT 1 FFE=5003.50 (LOWEST FLOOR) CENTRE AVENUE LOT 2 LOD LOD LOD LOD LOD LOD LOD Sheet Of 17 Sheets 200 S���� C������ A�����, S���� 010 F��� C������, C������� 80524 E N G I N E E R I N G � � � � � � �� PHONE: 970.221.4158 FAX: 970.221.4159 ���.�������������������.��� SUNSHINE HOUSE - FC 139 CENTRE FOR ADVANCED TECHNOLOGY 23 FILING 01.28.14 C4.00 DRAINAGE EXHIBIT CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R LEGEND: NORTH NOTES: / / / / / / / / / / / / / / / / / / / / / / / / / / / / UD B1 f2 BENCHMARK LOD FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION FEMA REFERENCE: FIELD SURVEY BY: & October 04, 2013 Conditions) 0.69 0.37 0.46 14.7 13.7 0.8 2.2 Page 7 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\SUMMARY-TABLE Tc (min) 10-yr Tc (min) 100-yr Tc (min) a1 OS1-3 & A1 (Ultimate Design) No 0.25 0.25 0.31 234.00 7.26% 12.6 12.6 11.6 N/A N/A N/A 319 4.93% 3.33 1.6 14 14 13 b1 OS3 & B1 (Existing Conditions) No 0.25 0.25 0.31 308.00 7.75% 14.1 14.1 13.1 51 0.51% 1.43 0.6 N/A N/A N/A 15 15 14 COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS C. Snowdon December 20, 2013 Design Point Basin IDs Overland Flow Gutter/Pipe Flow Swale Flow Time of Concentration (Equation RO-4) 3 1 1 . 87 1 . 1 * S Ti C Cf L  Page 5 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\Comb-Tc-10-yr_&_100-yr July 18, 2012 **Soil Classification of site is Sandy Loam** 10-year Cf = 1.00 Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Page 4 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\Comb-C-Values os3 OS3 0.29 11 11 11 0.87 0.87 1.00 2.13 3.63 7.57 0.54 0.93 2.22 os4 OS4 0.08 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 0.21 0.35 0.83 Page 3 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\Direct-Runoff Tc (min) 10-yr Tc (min) 100-yr Tc (min) a1 A1 No 0.25 0.25 0.31 40 9.53% 4.7 4.7 4.4 N/A N/A N/A 42 4.36% 3.13 0.2 5 5 5 a2 A2 No 0.74 0.74 0.93 31 5.13% 2.2 2.2 1.1 139 3.14% 3.54 0.7 N/A N/A N/A 5 5 5 a3 A3 No 0.46 0.46 0.58 43 10.00% 3.6 3.6 3.0 N/A N/A N/A 52 3.00% 2.60 0.3 5 5 5 a4 A4 No 0.95 0.95 1.00 60 10.00% 1.0 1.0 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 a5 A5 No 0.95 0.95 1.00 54 10.00% 1.0 1.0 0.6 N/A N/A N/A N/A N/A N/A 5 5 5 b1 B1 No 0.95 0.95 1.00 124 3.85% 2.0 2.0 1.3 71 0.51% 1.42 0.8 N/A N/A N/A 5 5 5 b2 B2 No 0.95 0.95 1.00 43 10.00% 0.9 0.9 0.6 N/A N/A N/A 69 2.00% 2.12 0.5 5 5 5 b3 B3 No 0.25 0.25 0.31 57 10.00% 5.6 5.6 5.2 40 4.00% 4.00 0.2 N/A N/A N/A 6 6 5 b4 B4 No 0.25 0.25 0.31 56 10.00% 5.5 5.5 5.1 N/A N/A N/A N/A N/A N/A 6 6 5 c1 C1 No 0.95 0.95 1.00 57 10.00% 1.0 1.0 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 d1 D1 No 0.25 0.25 0.31 56 17.93% 4.5 4.5 4.2 N/A N/A N/A 248 1.16% 1.61 2.6 7 7 7 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter/Pipe Flow Swale Flow Design Point Basin Overland Flow C. Snowdon December 20, 2013 Time of Concentration (Equation RO-4) 3 1 1 . 87 1 . 1 * S Ti C Cf L  os1 OS1 No 0.87 0.87 1.00 250 6.80% 3.6 3.6 1.6 N/A N/A N/A 250 4.56% 3.20 1.3 5 5 5 os2 OS2 No 0.87 0.87 1.00 260 8.23% 3.4 3.4 1.5 N/A N/A N/A N/A N/A N/A 5 5 5 os3 OS3 No 0.16 0.16 0.20 190 9.84% 11.3 11.3 10.9 N/A N/A N/A N/A N/A N/A 11 11 11 os4 OS4 No 0.00 0.00 0.00 20 7.05% 4.8 4.8 4.8 N/A N/A N/A N/A N/A N/A 5 5 5 Page 2 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\Tc-10-yr_&_100-yr B2 3876 0.09 0.00 0.02 0.03 0.00 0.00 0.05 0.54 0.54 0.67 43% B3 6500 0.15 0.00 0.01 0.03 0.00 0.00 0.11 0.37 0.37 0.46 24% B4 1355 0.03 0.00 0.00 0.03 0.00 0.00 0.00 0.95 0.95 1.00 90% C1 1383 0.03 0.00 0.00 0.03 0.00 0.00 0.00 0.95 0.95 1.00 90% D1 36146 0.83 0.00 0.02 0.03 0.00 0.00 0.78 0.20 0.20 0.25 5% OS1 55438 1.27 1.15 0.00 0.00 0.00 0.00 0.13 0.87 0.87 1.00 90% OS2 10518 0.24 0.22 0.00 0.00 0.00 0.00 0.02 0.87 0.87 1.00 90% OS3 12783 0.29 0.26 0.00 0.00 0.00 0.00 0.03 0.87 0.87 1.00 90% OS4 3627 0.08 0.07 0.00 0.00 0.00 0.00 0.01 0.87 0.87 1.00 90% TOTAL 167350 3.84 0.26 0.11 0.24 0.00 0.10 3.24 0.29 0.29 0.36 57% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 December 20, 2013 **Soil Classification of site is Sandy Loam** Page 1 of 7 D:\Projects\232-023\Drainage\Hydrology\232-023_Rational-Calcs.xlsx\C-Values ) Incremental Vol. (ft 3 ) Calc. Depths Calc. Depths 3 V D * A 1 A 2 A 1 * A 2   7/8 in 1 4996.80 8558.13 0.20 1666.09 14933.46 0.3428 4997.00 9047.56 0.20 1760.34 16693.80 0.3832 4997.20 9628.90 0.20 1867.34 18561.15 0.4261 4997.40 10263.52 0.20 1988.90 20550.05 0.4718 4997.60 10944.97 0.20 2120.48 22670.54 0.5204 4997.80 11685.66 0.20 2262.66 24933.20 0.5724 4998.00 12478.22 0.20 2415.95 27349.15 0.6279 4998.20 13300.71 0.20 2577.46 29926.61 0.6870 4998.40 14139.30 0.20 2743.57 32670.18 0.7500 4998.60 15008.50 0.20 2914.35 35584.53 0.8169 WQ Surface Elevation WQ Depth 100-yr Detention Elevation 100-yr Detention Depth N/A 4997.63 3.83 N/A Calc. Depths Calc. Depths 3 V D * A 1 A 2 A 1 * A 2   7/8 in 1 ¸ ¹ · ¨ © § D2 D2 0.75 5 5 5 0.78 0.78 0.98 2.85 4.87 9.95 1.7 2.9 7.4 X X 3.84 20 20 19 0.88 0.88 1.00 1.63 2.78 5.84 5.5 9.4 22.4 CH1 CH1 0.04 5 5 5 0.80 0.80 1.00 2.85 4.87 9.95 0.1 0.2 0.4 CH2 CH2 0.16 5 5 5 0.41 0.41 0.51 2.85 4.87 9.95 0.2 0.3 0.8 OS1 OS1 1.00 10 10 9 0.25 0.25 0.31 2.26 3.86 8.03 0.6 1.0 2.5 OS2 OS2 1.74 14 14 13 0.25 0.25 0.31 1.92 3.29 6.92 0.8 1.4 3.8 OS3 OS3 15.42 75 75 71 0.25 0.25 0.31 0.69 1.19 2.58 2.7 4.6 12.4 OS4 OS4 0.66 12 12 12 0.88 0.88 1.00 2.05 3.50 7.29 1.2 2.0 4.8 OS5 OS5 0.23 5 5 5 0.86 0.86 1.00 2.85 4.87 9.95 0.6 1.0 2.3 OS6 OS6 0.29 5 5 5 0.80 0.80 1.00 2.85 4.87 9.95 0.7 1.1 2.9 D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\Direct-Runoff 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) A1 A1-A4, B1, B2, C1-C4, D1, D2, X 5 5 5 1069 0.5 1.41 12.6 909 1.3 1.70 8.9 27 27 27 C4 A1-A4, B1, B2, C4 5 5 5 1069 0.5 1.41 12.6 95 1.3 1.71 0.9 19 19 19 Design Point Basins Upstream Design Point D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\Combined-Tc Tc (min) 10-yr Tc (min) 100-yr Tc (min) A1 A1 No 0.35 0.35 0.44 20 25.0 2.1 2.1 1.9 0 0.0 0.00 N/A 910 1.2 1.64 9.2 11 11 11 A2 A2 No 0.95 0.95 1.00 144 3.8 2.2 2.2 1.4 124 0.5 1.41 1.5 0 0.0 0.00 N/A 5 5 5 A3 A3 No 0.35 0.35 0.44 32 20.0 2.9 2.9 2.6 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5 5 5 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter Flow Swale Flow Design Point Basin Overland Flow A. Reese January 6, 2012 Time of Concentration (Equation RO-4) 3 1 1 . 87 1 . 1 * S Ti C Cf L  A3 A3 No 0.35 0.35 0.44 32 20.0 2.9 2.9 2.6 0 0.0 0.00 N/A 0 0.0 0.00 N/A 5 5 5 A4 A4 No 0.95 0.95 1.00 145 3.8 2.2 2.2 1.4 247 0.9 1.90 2.2 0 0.0 0.00 N/A 5 5 5 B1 B1 No 0.95 0.95 1.00 18 2.3 0.9 0.9 0.6 937 0.8 1.77 8.8 0 0.0 0.00 N/A 10 10 9 B2a B2a No 0.95 0.95 1.00 18 2.3 0.9 0.9 0.6 946 0.8 1.74 9.0 0 0.0 0.00 N/A 10 10 10 B2b B2b No 0.35 0.35 0.44 15 15.0 2.2 2.2 1.9 0 0.0 0.00 N/A 175 0.5 1.06 2.7 5 5 5 B2c B2c No 0.35 0.35 0.44 75 17.0 4.7 4.7 4.2 0 0.0 0.00 N/A 350 0.9 1.38 4.2 9 9 8 C1 C1 No 0.95 0.95 1.00 16 2.3 0.9 0.9 0.6 713 1.8 2.65 4.5 0 0.0 0.00 N/A 5 5 5 C2 C2 No 0.95 0.95 1.00 16 2.3 0.9 0.9 0.6 651 1.9 2.77 3.9 0 0.0 0.00 N/A 5 5 5 C3 C3 No 0.95 0.95 1.00 162 3.4 2.4 2.4 1.6 69 0.5 1.41 0.8 0 0.0 0.00 N/A 5 5 5 C4 C4 No 0.95 0.95 1.00 198 2.7 2.8 2.8 1.9 65 2.1 2.88 0.4 0 0.0 0.00 N/A 5 5 5 D1 D1 No 0.95 0.95 1.00 28 4.9 0.9 0.9 0.6 661 3.3 3.62 3.0 0 0.0 0.00 N/A 5 5 5 D2 D2 No 0.95 0.95 1.00 25 4.4 0.9 0.9 0.6 920 3.6 3.77 4.1 0 0.0 0.00 N/A 5 5 5 X X No 0.25 0.25 0.31 467 6.6 18.3 18.3 17.0 0 0.0 0.00 N/A 242 2.9 2.55 1.6 20 20 19 CH1 CH1 No 0.95 0.95 1.00 18 2.3 0.9 0.9 0.6 55 0.5 1.41 0.6 0 0.0 0.00 N/A 5 5 5 CH2 CH2 No 0.95 0.95 1.00 18 2.3 0.9 0.9 0.6 55 0.5 1.41 0.7 0 0.0 0.00 N/A 5 5 5 OS1 OS1 No 0.25 0.25 0.31 156 8.1 9.9 9.9 9.2 0 0.0 0.00 N/A 0 0.0 0.00 N/A 10 10 9 OS2 OS2 No 0.25 0.25 0.31 243 5.4 14.1 14.1 13.1 0 0.0 0.00 N/A 0 0.0 0.00 N/A 14 14 13 OS3 OS3 Yes 0.25 0.25 0.31 500 0.2 60.8 60.8 56.3 0 0.0 0.00 N/A 815 0.4 0.95 14.3 75 75 71 OS4 OS4 No 0.25 0.25 0.31 25 2.0 6.3 6.3 5.8 815 1.3 2.28 6.0 0 0.0 0.00 N/A 12 12 12 OS5 OS5 No 0.95 0.95 1.00 25 0.4 1.9 1.9 1.3 299 1.8 2.65 1.9 0 0.0 0.00 N/A 5 5 5 OS6 OS6 No 0.95 0.95 1.00 25 3.0 1.0 1.0 0.6 380 1.2 2.19 2.9 0 0.0 0.00 N/A 5 5 5 D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\Tc-2-yr_&_100-yr C3 89,792 2.06 0.78 0.32 0.37 0.00 0.59 0.75 0.75 0.94 68.0 C4 53,675 1.23 0.48 0.24 0.15 0.00 0.36 0.74 0.74 0.93 67.5 D1 40,718 0.93 0.34 0.25 0.13 0.00 0.21 0.79 0.79 0.99 73.3 D2 32,884 0.75 0.40 0.17 0.00 0.00 0.18 0.78 0.78 0.98 73.9 X 167,347 3.84 3.46 0.00 0.00 0.00 0.38 0.88 0.88 1.00 90.0 Developed 989,087 22.71 9.01 2.49 2.37 0.00 8.84 0.68 0.68 0.85 58.9 CH1 1,849 0.04 0.02 0.01 0.00 0.00 0.01 0.80 0.80 1.00 75.1 CH2 7,125 0.16 0.03 0.01 0.00 0.00 0.13 0.41 0.41 0.51 21.9 OS1 43,398 1.00 0.00 0.00 0.00 0.00 1.00 0.25 0.25 0.31 0.0 OS2 75,899 1.74 0.00 0.00 0.00 0.00 1.74 0.25 0.25 0.31 0.0 OS3 671,617 15.42 0.00 0.00 0.00 0.00 15.42 0.25 0.25 0.31 0.0 OS4 28,715 0.66 0.46 0.13 0.00 0.00 0.07 0.88 0.88 1.00 87.5 OS5 9,951 0.23 0.15 0.05 0.00 0.00 0.03 0.86 0.86 1.00 85.4 OS6 12,693 0.29 0.17 0.06 0.00 0.00 0.06 0.80 0.80 1.00 76.9 TOTAL 851,247 19.54 0.83 0.26 0.00 0.00 18.45 0.29 0.29 0.36 5.44 DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 January 6, 2012 D:\Projects\502-001\Drainage\Hydrology\502-001_Rational-Calcs.xlsx\C-Values Width of Riprap (ft) 2*d50, Depth of Riprap (ft) for L/2 Froude Parameter Q/D2.5 Max 6.0 or Q/WH1.5 Max 8.0 Riprap Type (From Figure MD-21 or MD-22) Page 1 of 3 B1-3 & R1-7 0.99 0.59 0.73 9.3 7.0 2.3 6.4 Page 7 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\SUMMARY-TABLE Tc (min) 10-yr Tc (min) 100-yr Tc (min) os1 OS1, A1, B1-2, B1-3 & R1-7 No 0.68 0.68 0.86 168 1.86% 8.2 8.2 4.8 245 6.27% 5.01 0.8 107 2.31% 2.28 0.8 10 10 6 b1 B1-2, B1-3 & R1-7 No 0.17 0.17 0.21 168 0 8 8 5 189 8.13% 5.70 0.6 87 2.84% 2.53 0.6 9 9 6 COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS C. Snowdon February 25, 2015 Design Point Basin IDs Overland Flow Gutter/Pipe Flow Swale Flow Time of Concentration (Equation RO-4) ( ) 3 1 1 . 87 1 . 1 * S Ti C Cf L - = Page 5 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\Comb-Tc-10-yr_&_100-yr Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Page 4 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\Comb-C-Values Tc (min) Q = C f ( C )( i )( A ) Page 3 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\Direct-Runoff Tc (min) 10-yr Tc (min) 100-yr Tc (min) a1 A1 No 0.68 0.68 0.86 86 15.47% 2.9 2.9 1.7 174 3.62% 3.81 0.8 N/A N/A N/A 5 5 5 b1 B1 No 0.17 0.17 0.21 40 11.73% 4.8 4.8 4.6 N/A N/A N/A 87 2.84% 2.53 0.6 5 5 5 b2 B2 No 0.67 0.67 0.84 146 4.51% 5.8 5.8 3.5 17 3.06% 3.50 0.1 N/A N/A N/A 6 6 5 c1 C1 No 0.21 0.21 0.26 36 4.08% 6.2 6.2 5.9 N/A N/A N/A N/A N/A N/A 6 6 6 c2 C2 No 0.36 0.36 0.45 15 4.07% 3.4 3.4 3.0 N/A N/A N/A 204 6.86% 3.93 0.9 5 5 5 c3 C3 No 0.58 0.58 0.73 131 2.39% 8.3 8.3 6.0 61 1.05% 2.05 0.5 N/A N/A N/A 9 9 6 r1 R1 No 0.95 0.95 1.00 41 5.00% 1.1 1.1 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r2 R2 No 0.95 0.95 1.00 43 5.00% 1.1 1.1 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r3 R3 No 0.95 0.95 1.00 36 5.00% 1.0 1.0 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r4 R4 No 0.95 0.95 1.00 46 5.00% 1.1 1.1 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r5 R5 No 0.95 0.95 1.00 40 5.00% 1.0 1.0 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r6 R6 No 0.95 0.95 1.00 38 5.00% 1.0 1.0 0.7 N/A N/A N/A N/A N/A N/A 5 5 5 r7 R7 No 0.95 0.95 1.00 77 5.00% 1.4 1.4 1.0 N/A N/A N/A N/A N/A N/A 5 5 5 os1 OS1 No 0.64 0.64 0.80 42 4.36% 3.4 3.4 2.3 N/A N/A N/A 42 14.02% 5.62 0.1 5 5 5 os2 OS2 No 0.89 0.89 1.00 50 5.44% 1.5 1.5 0.8 26 5.92% 4.87 0.1 N/A N/A N/A 5 5 5 os3 OS3 No 0.15 0.15 0.19 51 17.29% 4.9 4.9 4.7 N/A N/A N/A N/A N/A N/A 5 5 5 os4 OS4 No 0.16 0.16 0.20 19 28.11% 2.5 2.5 2.4 N/A N/A N/A N/A N/A N/A 5 5 5 DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Gutter/Pipe Flow Swale Flow Design Point Basin Overland Flow C. Snowdon February 25, 2015 Time of Concentration (Equation RO-4) ( ) 3 1 1 . 87 1 . 1 * S Ti C Cf L - = Page 2 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\Tc-10-yr_&_100-yr R1 824 0.019 0.000 0.000 0.019 0.000 0.000 0.00 0.95 0.95 1.00 90% R2 1171 0.027 0.000 0.000 0.027 0.000 0.000 0.00 0.95 0.95 1.00 90% R3 956 0.022 0.000 0.000 0.022 0.000 0.000 0.00 0.95 0.95 1.00 90% R4 1053 0.024 0.000 0.000 0.024 0.000 0.000 0.00 0.95 0.95 1.00 90% R5 1374 0.032 0.000 0.000 0.032 0.000 0.000 0.00 0.95 0.95 1.00 90% R6 1473 0.034 0.000 0.000 0.034 0.000 0.000 0.00 0.95 0.95 1.00 90% R7 2087 0.048 0.000 0.000 0.048 0.000 0.000 0.00 0.95 0.95 1.00 90% OS1 4214 0.097 0.052 0.007 0.000 0.000 0.000 0.04 0.64 0.64 0.80 60% OS2 1495 0.034 0.029 0.003 0.000 0.000 0.000 0.00 0.89 0.89 1.00 92% OS3 1335 0.031 0.000 0.000 0.000 0.000 0.000 0.03 0.15 0.15 0.19 0% OS4 2271 0.052 0.000 0.000 0.000 0.000 0.000 0.05 0.16 0.16 0.20 1% TOTAL 82229 1.888 0.573 0.175 0.269 0.000 0.227 0.87 0.63 0.63 0.79 52% DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. 10-year Cf = 1.00 February 25, 2015 **Soil Classification of site is Sandy Loam** Page 1 of 7 D:\Projects\232-033\Drainage\Hydrology\232-033_Rational-Calcs.xlsx\C-Values