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HomeMy WebLinkAboutHOMESTEAD AT CLARENDON HILLS - FDP200032 - - DRAINAGE REPORT December 18, 2020 DRAINAGE LETTER AND LID REPORT HOMESTEAD AT CLARENDON HILLS Fort Collins, Colorado Prepared for: Kenneth R. Mitchell Mosaic Real Estate LLC 1021 Nightingale Drive Fort Collins, Colorado. 80525 Prepared by: 301 North Mason Street, Suite 100 Fort Collins, Colorado 80524 Phone: 970.221.4158 www.northernengineering.com Project Number: 1013-008 Drainage Letter and LID Report – Homestead at Clarendon Hills Date: December 18, 2020 Project: Homestead at Clarendon Hills Project No. 1013-008 Preliminary Development Plan (PDP) Fort Collins, Colorado Attn: City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 To whom it may concern: This letter serves to address the stormwater impacts of the proposed project known as “Homestead at Clarendon Hills”. The site is located in southwest Fort Collins bounded to the north by Front Range Community College, to the east by existing Clarendon Hills Subdivision, to the south by Clarendon Hills Drive and Langdale Drive, and to the west by South Shields Street. The project is part of the Drainage Report for Clarendon Hills by Stuart and Associates written in 1986. The proposed development consists of 8 low-density single-family lots and a detention area. The project site also contains an existing irrigation ditch along the north property line. The project was included in the drainage report for Clarendon Hills Subdivision. Therefore, this letter intends to show conformance with the approved drainage design, including general drainage patterns and imperviousness. This letter also documents how the project meets new Low Impact Development requirements implemented City of Fort Collins since the approval of the original project. Original Drainage Patterns The original Clarendon Hill drainage design divided the subdivision into 3 basins. The current project site is split by two of these basins - Drainage Basin A draining to the north, and Drainage Basin B draining to the south. Drainage Basin B flows into Clarendon Hills Drive and Langdale Drive and travels via gutter and pan flow south along Clarendon Hills Drive. The flow is then collected by inlets at Clarendon Hills Drive and Hinsdale Drive and conveyed to a series of existing detention ponds. Drainage Basin A generally flows to the northeast to an existing irrigation ditch on the property. A small undisturbed area north of the irrigation ditch will flow into the Front Range Community College drainage system. From there, it flows through existing drainage ways east to Mail Creek, and eventually to Fossil Creek. An Existing Drainage Exhibit and excerpts from the original report are provided in the appendices for reference. Page | 3 Proposed Drainage Patterns The Homestead at Clarendon Hills project was divided into seven proposed drainage basins that essentially follow the established drainage patterns, as well as the drainage patterns approved with the Drainage Report for Clarendon Hills. Basin A encompasses the rear of the lots and open space between the rear lot lines and the existing irrigation ditch. The only proposed improvements with Basin A are landscaping in the rear of the lots. Flows from the basin will drain north into the irrigation ditch. Basin A is consistent with Basin A from the Drainage Report for Clarendon Hills. Basin B will roughly match the existing area draining south to the existing Clarendon Hills ponds. Proposed improvements will include single-family homes, the front and side of the lots, driveways, walks, and detention area. Basin B is further subdivided into Basins B1, B2, B3, and B4. Basins B1 and B3 consists of the open space at the west and east ends that will discharge into the Clarendon Hills and Langdon Drives curb and gutter. Basins B2 consists of Lots 1 through 8 building envelopes, driveways and detention pond. The project was graded to allow the building envelopes to drain to south, and small swales and curb and gutter in the shared driveway will convey drainage towards the detention pond. Basin B4 consists of the landscaping along the front of the pond that is incapable of draining into the detention pond. The release rate from the detention pond is reduced to accommodate the undetained releases from Basins B1, B3, and B4. An exhibit calculating the release rate is included in the appendices. The percent impervious for the lots was developed by assuming a typical building footprint of 3,250 square feet. The building footprint was placed along the rear building envelope to maximize the length of the driveway. This resulted in 49% imperviousness on a 7,982 sq. ft. lot. The area of the driveway was adjusted on the other lots to maintain a 49% imperviousness on the other lots. Along with the shared driveway, this resulted in a percent imperviousness of 51% in Basin B3. An exhibit is included in the appendices. Additionally, Basin OS1 and OS2 are on the east and the north sides of the site to quantify flows to the Front Range Community College campus. Basin OS1 consists of the side and rear of Lot 8 and adjacent open space. Basin OS2 is a small sliver of open space on the north side of the irrigation ditch that drains directly to the Front Range Community College campus. Development of Existing Runoff Coefficient The drainage for Clarendon Hills Subdivision was originally analyzed in the Drainage Report: Clarendon Hills: Fort Collins, Colorado prepared by Stuart and Associates in 1986 as part of the approval process for Clarendon Hills 1st Filing. Homestead for Clarendon Hills is in the northwest corner of the original drainage master plan for Clarendon Hills 1st Filing. In the approved original drainage report for Clarendon Hills (1st Filing), the project site was planned as office and multi-family with a developed runoff coefficient of C=0.50. According to the approved drainage report for Clarendon Hills 4th Filing, prepared by Land Development Services and dated April 9, 1991, a church site of 8.27 acres in the middle of the Clarendon Hills 4th Filing was assumed to be an offsite undeveloped drainage basin with a developed Page | 4 runoff coefficient of C=0.25. According to the approved drainage report for Clarendon Hills 6th Filing, prepared by Land Development Services and dated January 8, 1992, the original developer of Clarendon Hills swapped the northwest corner of Clarendon Hills (including Homestead for Clarendon Hills) for the church site in Clarendon Hills 4th Filing. The old church site was then developed as Clarendon Hills 6th Filing with runoff coefficients from 0.28 to 0.70. Because of the subsequent drainage studies and land swaps, we assumed an existing runoff coefficient of C=0.25 for Homestead at Clarendon Hills. A runoff coefficient of 0.25 is consistent with the following design considerations: • The Fort Collins Stormwater Criteria Manual for lawns with clayey soil and an average slope of 2% to 7% requires a runoff coefficient of C = 0.25. The existing slopes throughout the site is between 2% to 7% with clayey soil. • The drainage report for Clarendon Hills 4th Filing assumed a runoff coefficient C=0.25 for the church site, and the church site was subsequently part of a land swap for the northwest corner of the Clarendon Hills Subdivision. Detention Per the Clarendon Hills 1st Filing Drainage Report, “The ponds were designed using a mass diagram that required 10.46 acre-feet to detain the 100-year developed storm and release at a 2-year historic rate…”. Assuming a historic runoff coefficient of 0.25, detention from Basin B was provided as long as the overall flow at Design Point B does not exceed 1.9 cfs. Because of the increased impervious area within Basin B, detention is required within Basin B2 to reduce the post-developed flow rates at Design Point B to equal or less than 1.9 cfs. Since Basins B1, B3, and B4 will be released into the surrounding curb and gutter undetained, the detention pond in Basin B2 is designed to release the 100-year event at 0.3 cfs. A release rate of 1.2 cfs is required to maintain a 100-year flow rate of 1.9 cfs at Design Point B. (See the included flowrate calculations included in the appendices.) Detention Spillway The detention pond is designed to overflow at the west driveway entrance on Clarendon Hills Drive. In the even the outlet orifice is blocked, stormwater will first overflow through a weir into the west rain garden. Then, it will overflow through a curb cut at the northwest end of the rain garden. Finally, stormwater will overflow through the curb and gutter at a high point located at the back of sidewalk at the west entrance. Hydraulic calculations are included in the appendices. Inlets By limiting the 100-year flowrate at Design Point B, the flowrate at the existing inlets will match or decrease from the projected flowrates in the previously approved Clarendon Hills drainage reports. This results in matching or decreasing runoff to the existing inlets that were designed and approved with the earlier project, so no additional inlet calculations have been provided as a part of this report. Water Quality/LID Conformance According to Section 6.0 of the City of Fort Collins Stormwater Manual, “50% site treated with ‘standard’ water quality plus 50% site treated with LID (including pavers) equals 100% of site-treated (requirements met), or 25% site treated with ‘standard’ water quality plus 75% treated with LID equals 100% of site treated Page | 5 (requirements met)”, (page 14). This project proposes to treat 90.5% of the new impervious areas through two rain gardens as LID treatment. However, due to grading constraints along the east side of the project and requirements to provide a maintenance access for the ditch company, a gravel pedestrian path (9.5% of new impervious area) will not be treated by either the rain gardens or the detention pond. An exhibit showing the area of LID treatment is included in the appendices. Although exact impervious area is unavailable at this preliminary stage, the building envelopes will drain towards the rain gardens and the detention pond. The high point along each lot line is set at the rear of the building envelopes to maximize as much of the lot draining towards the south. Space limitations on the detention pond and rain gardens, natural buffer offsets from the ditch, and fire accessibility requirements restrict the drainage towards the front. Even with the grading restrictions, the proposed flowrate into the Mail Creek Basin is 2.2 cfs less than the existing flowrate. Erosion and Sediment Control During construction, the Contractor will follow the appropriate and applicable City of Fort Collins standards for erosion and sediment control. Since more than 10,000 sf will be disturbed as a part of this project, a comprehensive Stormwater Management Plan will be prepared for this project at final design. 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. Floodplains There are no regulatory floodplains associated with the project. Conclusions The proposed grading concept matches the original drainage patterns. The site matches the designed imperviousness draining to the existing Clarendon Hills curb and gutter. Onsite detention will be provided for the increased imperviousness of the area draining to towards the existing Clarendon Hills ponds, and onsite detention will be required to maintain historic flow rates within Clarendon Hills. Stormwater quality has been provided and meets the city requirements for Low Impact Development treatment. Therefore, it is my professional opinion that Homestead at Clarendon Hills satisfies all applicable stormwater criteria and will effectively limit potential damage associated with its stormwater runoff. Please do not hesitate to contact me if you have questions or require additional information. Sincerely, Frederick S. Wegert, PE Project Engineer ATTACHMENT 1 HYDROLOGIC CALCULATIONS TYPICAL LOT IMPERVIOUSNESS EXHIBIT FEMA Firmette FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 9 Figure 3.4-1. Rainfall IDF Curve – Fort Collins Runoff Coefficient1 Percent Impervious1 0.95 100% 0.95 90% 0.50 40% 0.55 50% 0.20 2% 0.20 2% Basin ID Basin Area (sq.ft.) Basin Area (acres) Asphalt, Concrete (acres)Rooftop (acres)Gravel (acres)Residential: Low Density (acres) Undeveloped: Greenbelts, Agriculture (acres) Lawns, Clayey Soil, Flat Slope < 2% (acres) Percent Impervious C2*Cf Cf = 1.00 C5*Cf Cf = 1.00 C10*Cf Cf = 1.00 C100*Cf Cf = 1.25 EX A 103,769 2.382 2%0.25 0.25 0.25 0.31 EX B 29,782 0.684 2%0.25 0.25 0.25 0.31 EX OS1 6,418 0.147 2%0.25 0.25 0.25 0.31 EX OS2 2,806 0.064 2%0.25 0.25 0.25 0.31 North 112,993 2.594 0.000 0.000 0.000 0.000 0.000 0.000 2%0.25 0.25 0.25 0.31 Lawns and Landscaping: Combined Basins 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Flat Slope < 2% USDA SOIL TYPE: C Undeveloped: Greenbelts, Agriculture Composite Runoff Coefficient2 1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM. Per Clarendon Hills 4th Filing Drainage Report: C = 0.25, Percent Impervious = 2% Per Clarendon Hills 4th Filing Drainage Report: C = 0.25, Percent Impervious = 2% Per Clarendon Hills 4th Filing Drainage Report: C = 0.25, Percent Impervious = 2% Per Clarendon Hills 4th Filing Drainage Report: C = 0.25, Percent Impervious = 2% EXISTING RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Gravel Residential: Low Density Homestead at Clarendon F. Wegert December 18, 2020 Project: Calculations By: Date: Character of Surface Streets, Parking Lots, Roofs, Alleys, and Drives: Page 1 of 3 Project: Calculations By: Date: Length (ft) Elev Up Elev Down Slope (%) Ti 2-Yr (min) Ti 10-Yr (min) Ti 100-Yr (min) Length (ft) Elev Up Elev Down Slope (%) Velocity (ft/s) Tt (min) Length (ft) Elev Up Elev Down Slope (%) Velocity (ft/s) Tt (min) Comp. Tc 2-Yr (min) Max. Tc 2-Yr (min) Tc 2-Yr (min) Comp. Tc 10-Yr (min) Max. Tc 10-Yr (min) Tc 10-Yr (min) Comp. Tc 100-Yr (min) Max. Tc 100-Yr (min) Tc 100-Yr (min) ex a EX A 60 92.89 89.01 6.47%6.6 6.6 6.1 N/A N/A N/A 705 89.01 85.49 0.50%1.06 11.09 17.69 14.25 14.25 17.69 14.25 14.25 17.21 14.25 17.21 ex b EX B 30 93.00 91.75 4.17%5.4 5.4 5.0 340 91.75 84.93 2.01 2.83 2.00 N/A N/A N/A 7.41 12.06 7.41 7.41 12.06 7.41 7.01 12.06 7.01 ex os1 EX OS1 96 93.00 89.90 3.23%10.5 10.5 9.8 N/A N/A N/A 98 89.90 86.13 3.85%2.94 0.56 11.09 11.08 11.08 11.09 11.08 11.08 10.32 11.08 10.32 ex os2 EX OS2 45 92.23 88.81 7.60%5.4 5.4 5.0 N/A N/A N/A N/A N/A N/A 5.42 10.25 5.42 5.42 10.25 5.42 5.02 10.25 5.02 ex a North 65 93.83 88.55 8.12%6.4 6.4 5.9 N/A N/A N/A 665 88.55 85.49 0.46%1.02 10.89 17.27 14.06 14.06 17.27 14.06 14.06 16.80 14.06 16.80 Time of Concentration Combined Basins Rational Equation: Q = CiA (Equation 6-1 per MHFD) Design Point Basin Overland Flow Channelized Flow Swale Flow Velocity (Swale Flow), V = 15·S ½ EXISTING TIME OF CONCENTRATION COMPUTATIONS (MHFD) Overland Flow, Time of Concentration: Homestead at Clarendon Gutter/Swale Flow, Time of Concentration:F. Wegert Tt = L / 60V (Equation 6-4 per MHFD)December 18, 2020 Tc = Ti + Tt (Equation 6-2 per MHFD) Intensity, i (per Table 3.4-1 of the Fort Collins Stormwater Manual) Velocity (Gutter Flow), V = 20·S ½ (Equation 6-4 per MHFD) (Equation 3.3-2 per Fort Collins } 𝑆𝑖=1.87 1.1 −𝐶∗𝐶𝑓𝐿 𝑆ൗ13 Notes: 1)Add 4900 to all elevations. 2) Flow path (Tc) for Basin EX A includes the flowline for the Smith Lateral to Design Point ex a. Because the Smith Lateral has a slope of 0.50% for a length of 705 feet, the computed Tc of 17.21 minutes was used for the Tc. Page 2 of 3 Tc2 Tc10 Tc100 C2 C10 C100 I2 (in/hr) I10 (in/hr) I100 (in/hr) Q2 (cfs) Q10 (cfs) Q100 (cfs) ex a EX A 2.382 14.25 14.25 17.21 0.25 0.25 0.31 1.92 3.29 6.10 1.1 2.0 4.5 ex b EX B 0.684 7.41 7.41 7.01 0.25 0.25 0.31 2.52 4.31 8.80 0.4 0.7 1.9 ex os1 EX OS1 0.147 11.08 11.08 10.32 0.25 0.25 0.31 2.13 3.63 7.72 0.1 0.1 0.4 ex os2 EX OS2 0.064 5.42 5.42 5.02 0.25 0.25 0.31 2.85 4.87 9.95 0.0 0.1 0.2 ex a North 2.594 14.06 14.06 16.80 0.25 0.25 0.31 1.92 3.29 6.20 1.25 2.13 5.03 Combined Basins Velocity (Swale Flow), V = 15·S ½ Rational Equation: Q = CiA (Equation 6-1 per MHFD) Design Point Basin Area (acres) Tc (Min)Runoff C Intensity Flow Velocity (Gutter Flow), V = 20·S ½ EXISTING DIRECT RUNOFF COMPUTATIONS (MHFD) Overland Flow, Time of Concentration: Project:Homestead at Clarendon Gutter/Swale Flow, Time of Concentration:Calculations By:F. Wegert Tt = L / 60V (Equation 6-4 per MHFD)Date:December 18, 2020 Tc = Ti + Tt (Equation 6-2 per MHFD) Intensity, I from Fig. 3.4.1 Fort Collins Stormwater Manual (Equation 6-4 per MHFD)} 𝑆𝑖=1.87 1.1 −𝐶∗𝐶𝑓𝐿 𝑆ൗ13 (Equation 3.3-2 per Fort Collins Stormwater Manual) Page 3 of 3 Runoff Coefficient1 Percent Impervious1 0.95 100% 0.95 90% 0.50 40% 0.55 50% 0.20 2% 0.20 2% Basin ID Basin Area (sq.ft.) Basin Area (acres) Asphalt, Concrete (acres)Rooftop (acres)Gravel (acres)Residential: Low Density (acres) Undeveloped: Greenbelts, Agriculture (acres) Lawns, Clayey Soil, Flat Slope < 2% (acres) Percent Impervious C2*Cf Cf = 1.00 C5*Cf Cf = 1.00 C10*Cf Cf = 1.00 C100*Cf Cf = 1.25 A 59,611 1.368 0.000 0.000 0.176 0.000 1.193 0.000 7%0.24 0.24 0.24 0.30 B1 1,772 0.041 0.000 0.000 0.012 0.000 0.000 0.029 13%0.29 0.29 0.29 0.36 B2 70,997 1.630 0.302 0.574 0.000 0.000 0.000 0.753 51%0.60 0.60 0.60 0.75 B3 552 0.013 0.000 0.000 0.000 0.000 0.000 0.013 2%0.20 0.20 0.20 0.25 B4 3,034 0.070 2%0.25 0.25 0.25 0.31 OS1 4,023 0.092 0.000 0.000 0.028 0.044 0.020 0.000 36%0.46 0.46 0.46 0.57 OS2 2,806 0.064 2%0.25 0.25 0.25 0.31 North 66,440 1.525 0.000 0.000 0.203 0.044 1.277 0.000 8%0.25 0.25 0.25 0.31 South 76,355 1.753 0.302 0.574 0.012 0.000 0.000 0.864 48%0.58 0.58 0.58 0.72 DEVELOPED RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Gravel Residential: Low Density Homestead at Clarendon F. Wegert December 18, 2020 Project: Calculations By: Date: Character of Surface Streets, Parking Lots, Roofs, Alleys, and Drives: Lawns and Landscaping: Combined Basins 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Flat Slope < 2% USDA SOIL TYPE: C Undeveloped: Greenbelts, Agriculture Composite Runoff Coefficient2 1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM. Lawns, Clayey Soil > 7%: C = 0.35, Percent Impervious = 2% Lawns, Clayey Soil > 7%: C = 0.35, Percent Impervious = 2% Page 1 of 3 Length (ft) Elev Up Elev Down Slope (%) Ti 2-Yr (min) Ti 10-Yr (min) Ti 100-Yr (min) Length (ft) Elev Up Elev Down Slope (%) Velocity (ft/s) Tt (min) Length (ft) Elev Up Elev Down Slope (%) Velocity (ft/s) Tt (min) Comp. Tc 2-Yr (min) Max. Tc 2-Yr (min) Tc 2-Yr (min) Comp. Tc 10-Yr (min) Max. Tc 10-Yr (min) Tc 10-Yr (min) Comp. Tc 100-Yr (min) Max. Tc 100-Yr (min) Tc 100-Yr (min) a A 60 92.89 89.01 6.47%6.7 6.7 6.2 N/A N/A N/A 705 89.01 85.49 0.50%1.06 11.09 17.78 14.25 14.25 17.78 14.25 14.25 17.32 14.25 17.32 b B1 40 93.97 92.33 4.10%6.0 6.0 5.5 326 92.33 84.93 2.27 3.01 1.80 N/A N/A N/A 7.80 12.03 7.80 7.80 12.03 7.80 7.27 12.03 7.27 b B2 120 94.10 91.77 1.94%8.2 8.2 5.7 375 91.77 84.93 1.82 2.70 2.31 N/A N/A N/A 10.47 12.75 10.47 10.47 12.75 10.47 7.99 12.75 7.99 b B3 40 92.18 91.54 1.60%9.1 9.1 8.6 366 91.54 84.93 1.81 2.69 2.27 N/A N/A N/A 11.37 12.26 11.37 11.37 12.26 11.37 10.86 12.26 10.86 b B4 20 91.89 90.41 7.40%3.6 3.6 3.4 167 90.41 84.93 3.28 3.62 0.77 N/A N/A N/A 4.42 11.04 5.00 4.42 11.04 5.00 4.15 11.04 5.00 os1 OS1 35 92.28 91.47 2.31%5.4 5.4 4.4 N/A N/A N/A 134 91.47 86.13 3.99%2.99 0.75 6.12 10.94 6.12 6.12 10.94 6.12 5.16 10.94 5.16 os2 OS2 25 92.23 90.55 6.72%4.2 4.2 3.9 N/A N/A N/A N/A N/A N/A 4.21 10.14 5.00 4.21 10.14 5.00 3.90 10.14 5.00 a North 60 92.89 89.01 6.47%6.6 6.6 6.1 N/A N/A N/A 705 89.01 85.49 0.50%1.06 11.09 17.69 14.25 14.25 17.69 14.25 14.25 17.21 14.25 17.21 b South 95 94.23 92.41 1.92%7.7 7.7 5.6 350 92.41 84.93 2.14 2.92 2.00 N/A N/A N/A 9.67 12.47 9.67 9.67 12.47 9.67 7.55 12.47 7.55 Rational Equation: Q = CiA (Equation 6-1 per MHFD) Velocity (Swale Flow), V = 15·S ½ DEVELOPED TIME OF CONCENTRATION COMPUTATIONS (MHFD) Overland Flow, Time of Concentration: Homestead at Clarendon Gutter/Swale Flow, Time of Concentration:F. Wegert Tt = L / 60V (Equation 6-4 per MHFD)December 18, 2020 Tc = Ti + Tt (Equation 6-2 per MHFD) Velocity (Gutter Flow), V = 20·S ½ Project: Calculations By: Date: Intensity, i (per Table 3.4-1 of the Fort Collins Stormwater Manual) Time of Concentration Combined Basins Design Point Basin Overland Flow Channelized Flow Swale Flow (Equation 6-4 per MHFD) (Equation 3.3-2 per Fort Collins } 𝑆𝑖=1.87 1.1 −𝐶∗𝐶𝑓𝐿 𝑆ൗ13 Notes: 1)Add 4900 to all elevations. 2) Flow path (Tc) for Basin A includes the flowline for the Smith Lateral to Design Point a. Because the Smith Lateral has a slope of 0.50% for a length of 705 feet, the computed Tc of 17.32 minutes was used for the Tc. Page 2 of 3 Tc2 Tc10 Tc100 C2 C10 C100 I2 (in/hr) I10 (in/hr) I100 (in/hr) Q2 (cfs) Q10 (cfs) Q100 (cfs) a A 1.368 14.25 14.25 17.32 0.24 0.24 0.30 1.92 3.29 6.10 0.6 1.1 2.5 b B1 0.041 7.80 7.80 7.27 0.29 0.29 0.36 2.46 4.21 8.80 0.0 0.0 0.1 b B2 1.630 10.47 10.47 7.99 0.60 0.60 0.75 2.21 3.78 8.59 2.2 3.7 10.6 b B3 0.013 11.37 11.37 10.86 0.20 0.20 0.25 2.13 3.63 7.57 0.0 0.0 0.0 b B4 0.070 5.00 5.00 5.00 0.25 0.25 0.31 2.85 4.87 9.95 0.0 0.1 0.2 os1 OS1 0.092 6.12 6.12 5.16 0.46 0.46 0.57 2.67 4.56 9.95 0.1 0.2 0.5 os2 OS2 0.064 5.00 5.00 5.00 0.25 0.25 0.31 2.85 4.87 9.95 0.0 0.1 0.2 a North 1.525 14.25 14.25 17.21 0.25 0.25 0.31 1.92 3.29 6.10 0.7 1.3 2.9 b South 1.753 9.67 9.67 7.55 0.58 0.58 0.72 2.26 3.86 8.59 2.3 3.9 10.9 Velocity (Gutter Flow), V = 20·S ½ DEVELOPED DIRECT RUNOFF COMPUTATIONS (MHFD) Overland Flow, Time of Concentration: Project:Homestead at Clarendon Gutter/Swale Flow, Time of Concentration:Calculations By:F. Wegert Tt = L / 60V (Equation 6-4 per MHFD)Date:December 18, 2020 Tc = Ti + Tt (Equation 6-2 per MHFD) Intensity, I from Fig. 3.4.1 Fort Collins Stormwater Manual Combined Basins Velocity (Swale Flow), V = 15·S ½ Rational Equation: Q = CiA (Equation 6-1 per MHFD) Design Point Basin Area (acres) Tc (Min)Runoff C Intensity Flow (Equation 6-4 per MHFD)} 𝑆𝑖=1.87 1.1 −𝐶∗𝐶𝑓𝐿 𝑆ൗ13 (Equation 3.3-2 per Fort Collins Stormwater Manual) Page 3 of 3 / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /SINGLE - FAMILY RESIDENCE DRIVEWAY BUILDING ENVELOPE LOT LINE SHARE D D R I V E W A Y EASEMENT EASEMENT EASEMENT E N G I N E E R N GI EHTRON R N FIGURE 1 Typical Lot for Impervious Areas 12.18.2020 FORT COLLINS, CO P:\1013-008\DWG\EXHIBITS\1013-008_DRAINAGE_TYPLOT.DWG HOMESTEAD AT CLARENDON LEGEND ROOF DRIVEWAY PERVIOUS LOT SIZE = 7,982 SQ. FT. PERCENT IMPERVIOUS = 49% 3,250 SQ. FT. 701 SQ. FT. 4,031 SQ. FT. USGS The National Map: Orthoimagery. Data refreshed October, 2017. National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250Feet Ü105°5'59.00"W 40°31'15.27"N 105°5'21.55"W 40°30'47.92"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AR EAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR Regulator y Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X Future Conditions 1% AnnualChance Flood Hazard Zone XArea with Reduced Flood Risk due toLevee. See Notes.Zone X Area with Flood Risk due to Levee Zone D NO SCREE N Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culver t, or Storm SewerLevee, Dike, or Floodwall Cross Sections with 1% Annual Chance17.5 Water Surface ElevationCoastal Transect Coastal Transect BaselineProfile BaselineHydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of StudyJurisdiction Boundar y Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 4/5/2019 at 2:25:52 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following mapelements do not appear: basemap imagery, flood zone labels,legend, scale bar, map creation date, community identifiers,FIRM panel number, and FIRM effective date. Map images forunmapped and unmodernized areas cannot be used forregulatory purposes. Legend OTHER AREAS OFFLOOD HAZARD OTHER AREAS GENERALSTRUCTURES OTHERFEATURES MAP PANELS 8 1:6,000 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative proper ty location. ATTACHMENT 2 HYDRAULIC CALCULATIONS Culvert Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Dec 17 2020 Lot 7 Culvert Driveway 100-Year Invert Elev Dn (ft) = 5090.56 Pipe Length (ft) = 20.00 Slope (%) = 0.50 Invert Elev Up (ft) = 5090.66 Rise (in) = 12.0 Shape = Circular Span (in) = 12.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 5092.80 Top Width (ft) = 16.00 Crest Width (ft) = 20.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 2.25 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 2.20 Qpipe (cfs) = 2.20 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 3.20 Veloc Up (ft/s) = 4.19 HGL Dn (ft) = 5091.38 HGL Up (ft) = 5091.29 Hw Elev (ft) = 5091.64 Hw/D (ft) = 0.98 Flow Regime = Inlet Control Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Dec 17 2020 Trench Drain - 100-Year Rectangular Bottom Width (ft) = 1.00 Total Depth (ft) = 1.81 Invert Elev (ft) = 100.00 Slope (%) = 1.50 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 5.12 Highlighted Depth (ft) = 0.76 Q (cfs) = 5.120 Area (sqft) = 0.76 Velocity (ft/s) = 6.74 Wetted Perim (ft) = 2.52 Crit Depth, Yc (ft) = 0.94 Top Width (ft) = 1.00 EGL (ft) = 1.47 0 .25 .5 .75 1 1.25 1.5 Elev (ft)Depth (ft)Section 99.50 -0.50 100.00 0.00 100.50 0.50 101.00 1.00 101.50 1.50 102.00 2.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Dec 17 2020 Valley Pan at East Driveway - 100-Year Triangular Side Slopes (z:1) = 60.00, 60.00 Total Depth (ft) = 0.30 Invert Elev (ft) = 100.00 Slope (%) = 1.70 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 3.00 Highlighted Depth (ft) = 0.14 Q (cfs) = 3.000 Area (sqft) = 1.18 Velocity (ft/s) = 2.55 Wetted Perim (ft) = 16.80 Crit Depth, Yc (ft) = 0.18 Top Width (ft) = 16.80 EGL (ft) = 0.24 0 5 10 15 20 25 30 35 40 45 50 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Dec 17 2020 Sidewalk Culvert and Chase - 100-Year Rectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.71 Invert Elev (ft) = 100.00 Slope (%) = 0.50 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 1.50 Highlighted Depth (ft) = 0.27 Q (cfs) = 1.500 Area (sqft) = 0.54 Velocity (ft/s) = 2.78 Wetted Perim (ft) = 2.54 Crit Depth, Yc (ft) = 0.26 Top Width (ft) = 2.00 EGL (ft) = 0.39 0 .5 1 1.5 2 2.5 3 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) Area Inlet Performance Curve: Rain Garden Overflow Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 3.1416*Dia.of grate * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate:Nyloplast 24" Dome Diameter of Grate (ft):2 Open Area of Grate (ft2):1.88 Rim Elevation (ft):5089.60 Reduction Factor:50% Depth vs. Flow: Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 5089.60 0.00 0.00 0.00 0.10 5089.70 0.30 1.60 0.30 0.20 5089.80 0.84 2.27 0.84 0.30 5089.90 1.55 2.77 1.55 0.40 5090.00 2.38 3.20 2.38 10-Year 0.50 5090.10 3.33 3.58 3.33 0.60 5090.20 4.38 3.92 3.92 0.70 5090.30 5.52 4.24 4.24 0.80 5090.40 6.74 4.53 4.53 0.90 5090.50 8.05 4.81 4.81 1.00 5090.60 9.42 5.07 5.07 100-Year 10-Year Design Flow =1.80 cfs100-Year Design Flow = 5.12 cfs 5.10.3 HPQ= 5.0)2(67.0 gHAQ= 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00Discharge (cfs)Stage (ft) Stage -Discharge Curves Weir Flow Orifice Flow Area Inlet Performance Curve: Detention Pond Overflow Governing Equations: At low flow depths, the inlet will act like a weir governed by the following equation: * where P = 2(L + W) * where H corresponds to the depth of water above the flowline At higher flow depths, the inlet will act like an orifice governed by the following equation: * where A equals the open area of the inlet grate * where H corresponds to the depth of water above the centroid of the cross-sectional area (A) The exact depth at which the inlet ceases to act like a weir, and begins to act like an orifice is unknown. However, what is known, is that the stage-discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. Input Parameters: Type of Grate:FABRICATED Length of Grate (ft):3.00 Width of Grate (ft):3.00 Open Area of Grate (ft2):7.65 Grate Elevation (ft):5089.60 Allowable Capacity:0.80 Depth vs. Flow: Depth Above Inlet (ft) Elevation (ft) Shallow Weir Flow (cfs) Orifice Flow (cfs) Actual Flow (cfs) 0.00 5089.60 0.00 0.00 0.00 0.10 5089.70 0.91 10.40 0.91 0.20 5089.80 2.58 14.71 2.58 0.30 5089.90 4.73 18.01 4.73 0.40 5090.00 7.29 20.80 7.29 0.52 5090.12 10.80 23.72 10.80 Q100 0.60 5090.20 13.39 25.48 13.39 0.70 5090.30 16.87 27.52 16.87 0.80 5090.40 20.61 29.42 20.61 0.90 5090.50 24.59 31.20 24.59 1.00 5090.60 28.80 32.89 28.80 100-Year Flow = 10.6 cfs 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00Discharge (cfs)Stage (ft) Stage -Discharge Curves Weir Flow Orifice Flow 5.10.3 HPQ= 5.0)2(67.0 gHAQ= ATTACHMENT 3 DETENTION POND CALCULATIONS STATE DRAIN TIME CALCULATIONS WATER QUALITY CALCULATIONS LID CALCULATIONS AND EXHIBIT Project Number: Project Name: Project Location: Date: Basin Notes Historic Basin EX A 4.6 cfs Historic Basin EX OS1 0.4 cfs Historic Basin EX OS2 0.2 cfs Total Q100 to the North 5.2 cfs Proposed Basin A 2.5 cfs Proposed Basin OS1 0.5 cfs Proposed Basin OS2 0.2 cfs Total Q100 to the North 3.2 cfs Change in Q100 to the North 2.0 cfs Results in a decrease for the 100-year storm. Basin Notes Historic Basin EX B 1.9 cfs Total Q100 to the South 1.9 cfs Proposed Basin B1 0.1 cfs Proposed Basin B3 0.0 cfs Proposed Basin B4 0.2 cfs Detention Pond Release Rate 1.5 cfs Pond release rate determined by subtracting Basin B1, B3, and B4 from Basin EX B. Total Q100 to the South 1.9 cfs Change in Q100 to the South 0.0 cfs No change for the 100-year storm. Q100 Historic vs. Developed Flowrates to the North Historic vs. Developed Flowrates to the South HISTORIC VS. DEVELOPED FLOWRATES 1013-008 Homestead at Clarendon Fort Collins, Colorado Q100 December 18, 2020 Pond No : B2 100-yr 0.75 12.74 min Storage 7373 ft3 1.63 acres Water Quality 0 ft3 Max Release Rate =1.50 cfs 0.17 ac-ft Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 3649 1.00 1.50 450 3199 10 7.720 5663 1.00 1.50 900 4763 15 6.520 7174 1.00 1.50 1350 5824 20 5.600 8215 1.00 1.50 1800 6415 25 4.980 9132 1.00 1.50 2250 6882 30 4.520 9946 1.00 1.50 2700 7246 35 4.080 10474 1.00 1.50 3150 7324 40 3.740 10973 1.00 1.50 3600 7373 45 3.460 11421 1.00 1.50 4050 7371 50 3.230 11846 1.00 1.50 4500 7346 55 3.030 12224 1.00 1.50 4950 7274 60 2.860 12587 1.00 1.50 5400 7187 65 2.720 12968 1.00 1.50 5850 7118 70 2.590 13298 1.00 1.50 6300 6998 75 2.480 13643 1.00 1.50 6750 6893 80 2.380 13966 1.00 1.50 7200 6766 85 2.290 14278 1.00 1.50 7650 6628 90 2.210 14589 1.00 1.50 8100 6489 95 2.130 14842 1.00 1.50 8550 6292 100 2.060 15110 1.00 1.50 9000 6110 105 2.000 15404 1.00 1.50 9450 5954 110 1.940 15653 1.00 1.50 9900 5753 115 1.890 15943 1.00 1.50 10350 5593 120 1.840 16196 1.00 1.50 10800 5396 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1013-008 Homestead at Clarendon Project Number : Project Name : Detention Pond A = Tc = Project Location : Design Point C = Design Storm Page 1 of 1 1013-008_Pond_FAA_Fort Collins A Lots.xls Project: Date: Outlet Elevation:5086.57 0.17 ac. ft. Grate Elevation:5089.6 0.19 ac. ft. Crest of Pond Elev.:5090.6 5089.41 Freeboard.:1.2 ft Maximum Elevation Minimum Elevation cu. ft.acre ft cu. ft.acre ft 5086.6 N/A 0.0 0 0.0 0.00 0.0 0.00 5087.0 5086.6 567.8 0.4 122.1 0.00 122.1 0.00 5087.5 5087.0 2,375.7 0.5 735.9 0.02 858.0 0.02 5088.0 5087.5 3,379.2 0.5 1,438.7 0.03 2,296.7 0.05 5088.5 5088.0 3,602.6 0.5 1,745.5 0.04 4,042.1 0.09 5089.0 5088.5 3,740.2 0.5 1,835.7 0.04 5,877.8 0.13 5089.5 5089.0 3,809.3 0.5 1,887.4 0.04 7,765.2 0.18 5090.0 5089.5 3,860.6 0.5 1,917.5 0.04 9,682.7 0.22 5090.6 5090.0 3,920.8 0.6 2,334.4 0.05 12,017.1 0.28 Volume at Grate: Project Number: Project Location: Calculations By: Pond No.: Detention Pond Stage Storage Curve Contour Contour Surface Area (ft2) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 1013-008 Fort Collins, Colorado F. Wegert B2 Elev at Design Volume: Homestead at Clarendon 12/18/2020 Pond Outlet and Volume Data Design Volume: 12/17/2020 6:00 PM P:\1013-008\Drainage\Detention\ 1013-008_Stage-Storage A Lots.xlsx\Pond Stormwater Facility Name: Facility Location & Jurisdiction: User Input: Watershed Characteristics User Defined User Defined User Defined User Defined Selected BMP Type =RG Stage [ft]Area [ft^2]Stage [ft]Discharge [cfs] Watershed Area =1.63 acres 0.00 0 0.00 0.00 Watershed Length =500 ft 0.40 568 0.18 0.37 Watershed Length to Centroid =100 ft 0.90 2,376 0.43 0.58 Watershed Slope =0.018 ft/ft 1.40 3,379 0.68 0.73 Watershed Imperviousness =51.0%percent 1.90 3,603 0.93 0.85 Percentage Hydrologic Soil Group A =0.0%percent 2.40 3,740 1.18 0.96 Percentage Hydrologic Soil Group B =0.0%percent 2.90 3,809 1.43 1.05 Percentage Hydrologic Soil Groups C/D =100.0%percent 3.40 3,861 1.68 1.14 Target WQCV Drain Time =12.0 hours 4.00 3,921 1.93 1.22 2.18 1.30 User Input 2.43 1.37 2.68 1.44 2.84 1.48 2.93 1.51 3.18 1.57 3.43 1.63 3.68 1.69 4.00 1.76 After completing and printing this worksheet to a pdf, go to: https://maperture.digitaldataservices.com/gvh/?viewer=cswdif Create a new stormwater facility, and attach the PDF of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period =WQCV 2 Year 5 Year 10 Year 50 Year 100 Year One-Hour Rainfall Depth =N/A 0.82 1.14 1.40 2.27 2.86 in CUHP Runoff Volume =0.023 0.048 0.078 0.109 0.228 0.312 acre-ft Inflow Hydrograph Volume =N/A 0.048 0.078 0.109 0.228 0.312 acre-ft Time to Drain 97% of Inflow Volume =0.4 1.0 1.3 1.8 2.8 3.3 hours Time to Drain 99% of Inflow Volume =0.4 1.1 1.4 1.8 2.8 3.4 hours Maximum Ponding Depth =0.96 0.53 0.83 1.07 2.12 2.88 ft Maximum Ponded Area =0.06 0.02 0.05 0.06 0.08 0.09 acres Maximum Volume Stored =0.023 0.005 0.016 0.029 0.111 0.176 acre-ft Once CUHP has been run and the Stage-Area-Discharge information has been provided, click 'Process Data' to interpolate the Stage-Area-Volume-Discharge data and generate summary results in the table below. Once this is complete, click 'Print to PDF'. Stormwater Detention and Infiltration Design Data Sheet Homestead at Clarendon Fort Collins, Colorado SDI-Design Data v2.00, Released January 2020 Location for 1-hr Rainfall Depths (use dropdown): After providing required inputs above including 1-hour rainfall depths, click 'Run CUHP' to generate runoff hydrographs using the embedded Colorado Urban Hydrograph Procedure. SDI_Design_Data_v2.00.xlsm, Design Data 12/18/2020, 8:52 AM Booleans for Message Booleans for CUHP Watershed L:W 1 CUHP Inputs Complete Watershed Lc:L 1 CUHP Results Calculated Watershed Slope FALSE Time Interval RunOnce 1 CountA 1 Draintime Coeff 0.8 User Precip 1 Equal SA Inputs 1 Equal SD Inputs 1 Stormwater Detention and Infiltration Design Data Sheet 0 1 2 3 4 5 6 0.1 1 10FLOW [cfs]TIME [hr] 100YR IN 100YR OUT 50YR IN 50YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR OUT WQCV IN WQCV OUT 0 0.5 1 1.5 2 2.5 3 3.5 0.1 1 10 100PONDING DEPTH [ft]DRAIN TIME [hr] 100YR 50YR 10YR 5YR 2YR WQCV SDI_Design_Data_v2.00.xlsm, Design Data 12/18/2020, 8:52 AM Project Number : Project Name : Project Location : Pond No :Calc. By:F. Wegert Orifice Dia (in):5 9/16 Orifice Area (sf):0.1688 Orifice invert (ft):5086.57 Orifice Coefficient:0.65 Elevation Stage (ft)Velocity (ft/s)Flow Rate (cfs)Comments 5086.57 0.00 0.00 0.00 5086.75 0.18 2.21 0.37 5087.00 0.43 3.42 0.58 5087.25 0.68 4.30 0.73 5087.50 0.93 5.03 0.85 5087.75 1.18 5.66 0.96 5088.00 1.43 6.23 1.05 5088.25 1.68 6.76 1.14 5088.50 1.93 7.24 1.22 5088.75 2.18 7.70 1.30 5089.00 2.43 8.13 1.37 5089.25 2.68 8.54 1.44 5089.41 2.84 8.79 1.48 <-100 Year Elev. 5089.50 2.93 8.92 1.51 5089.75 3.18 9.30 1.57 5090.00 3.43 9.66 1.63 5090.25 3.68 10.00 1.69 5090.50 3.93 10.34 1.74 5090.75 4.18 10.66 1.80 5091.00 4.43 10.97 1.85 5091.25 4.68 11.28 1.90 5091.50 4.93 11.58 1.95 5091.75 5.18 11.87 2.00 ORIFICE RATING CURVE Orifice Rating Curve 1013-008 Homestead at Clarendon Fort Collins, Colorado Pond B2 Orifice Design Data Project Number : Project Name : Project Location : Pond No :Calc. By: Q=3.3LH 1.5 Length (L)=10.00 FT Crest Elevation =5089.70 FT Depth Above Crest (ft) Elevation (ft) Flow (cfs) 0.00 5089.70 0.00 0.10 5089.80 1.04 0.20 5089.90 2.95 0.30 5090.00 5.42 0.40 5090.10 8.35 0.47 5090.17 10.63 Q100 0.50 5090.20 11.67 0.60 5090.30 15.34 0.70 5090.40 19.33 0.80 5090.50 23.61 0.90 5090.60 28.18 Crest of Pond Q100 = 10.6 CFS Input Parameters: Depth vs. Flow: B2 SHARP-CRESTED WEIR This equation can be used to derive the stage-discharge relationship for a sharp crested weir where the depth of flow is small compared to the length of weir. Reference 1) Hydrologic Analysis and Design, Richard H McCuen, Prentice Hall, 1989. Pg.549. * where Q is flow rate in CFS * where L is the crest length of the weir (FT) * where H is the height of flow over the crest (FT) Governing Equations: 1013.008 Homestead at Clarendon Fort Collins, Colorado F. Wegert Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Friday, Dec 18 2020 Pond Spillway at West Driveway User-defined Invert Elev (ft) = 5089.65 Slope (%) = 0.50 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 10.60 (Sta, El, n)-(Sta, El, n)... ( 0.00, 5090.60)-(4.00, 5090.15, 0.012)-(4.10, 5089.65, 0.012)-(5.00, 5089.73, 0.012)-(114.03, 5090.02, 0.012) Highlighted Depth (ft) = 0.26 Q (cfs) = 10.60 Area (sqft) = 6.27 Velocity (ft/s) = 1.69 Wetted Perim (ft) = 68.72 Crit Depth, Yc (ft) = 0.26 Top Width (ft) = 68.50 EGL (ft) = 0.30 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 Elev (ft)Depth (ft)Section 5089.00 -0.65 5089.50 -0.15 5090.00 0.35 5090.50 0.85 5091.00 1.35 Sta (ft) UD UDUDUDUDT T/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /RAIN GARDENL A N G D A L E D R I V ECLARENDON HILLS DRIVEPROPOSED POND100-YEAR WSE = 5089.411' CURB CUT2' WIDE CONCRETE CHASEPROPOSED DRIVEWAYVERTICAL CURBAND GUTTEROUTLET PIPEOUTLET STRUCTURE2' WIDE METALSIDEWALK CULVERTHEADWALLPROPOSEDTRENCH DRAINPROVIDE 10' WIDEWEIR AT ELEV. 5089.7RAIN GARDENFIGURE 1Spillway InundationFORT COLLINS, COHOMESTEAD AT CLARENDONENGINEERNGIEHTRONRN12.18.2020P:\1013-008\DWG\EXHIBITS\1013-008_OVERFLOW INUNDATION.DWGAREA OF INUNDATIONFROM SPILLWAY Sheet 1 of 2 Designer: Company: Date: Project: Location: 1.Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =51.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.510 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.17 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area)Area =34,627 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =482 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 =12 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 =353 sq ft D) Actual Flat Surface Area AActual =495 sq ft E) Area at Design Depth (Top Surface Area)ATop =571 sq ft F) Rain Garden Total Volume VT=533 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3.Growing Media 4.Underdrain System A) Are underdrains provided? 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) Frederick S. Wegert Northern Engineering December 17, 2020 Homestead at Clarendon - East Rain Garden Fort Collins, Colorado UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 1013-008_UD-BMP_v3.07 Rain Garden East.xlsm, RG 12/17/2020, 5:17 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? 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) Frederick S. Wegert Northern Engineering December 17, 2020 Homestead at Clarendon - East Rain Garden Fort Collins, Colorado 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 1013-008_UD-BMP_v3.07 Rain Garden East.xlsm, RG 12/17/2020, 5:17 PM Project: Date: Bottom Elevation:5088.6 578 ft3 Overflow Elevation:5089.7 603 ft3 Crest of Pond Elev.:5090.5 5089.7 Freeboard.:0.8 ft 1 ft Maximum Elevation Minimum Elevation cu. ft.acre ft cu. ft.acre ft 5088.6 N/A 495.2 0 0.0 0.00 0.0 0.00 5089.0 5088.6 542.6 0.4 207.6 0.00 207.6 0.00 5089.5 5089.0 570.8 0.5 278.4 0.01 485.9 0.01 5090.0 5089.5 598.2 0.5 292.3 0.01 778.2 0.02 5090.5 5090.0 625.7 0.5 306.0 0.01 1,084.1 0.02 Water Depth: Volume at Overflow: Project Number: Project Location: Calculations By: Pond No.: Rain Garden Stage Storage Curve Contour Contour Surface Area (ft2) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 1013-008 Fort Collins, Colorado F. Wegert East Rain Garden Elev at Design Volume: Homestead at Clarendon 12/18/2020 Pond Outlet and Volume Data Design Volume1: Notes: 1) The MHFD spreadsheet UD-BMP is a password protected black box that prevents the user from multiplying the water quality volume by 120% per Fort Collins Stormwater Manual. Therefore, the Design Volume on this spreadsheet is 482 cu. ft. * 1.2. The 482 cu. ft. is the water quality volume from the UD - BMP. 12/17/2020 5:30 PM P:\1013-008\Drainage\LID\ 1013-008_Stage-Storage East.xlsx\Pond Sheet 1 of 2 Designer: Company: Date: Project: Location: 1.Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =51.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i =0.510 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV =0.17 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area)Area =31,852 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =444 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 =12 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 =325 sq ft D) Actual Flat Surface Area AActual =430 sq ft E) Area at Design Depth (Top Surface Area)ATop =570 sq ft F) Rain Garden Total Volume VT=500 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) Frederick S. Wegert Northern Engineering December 17, 2020 Homestead at Clarendon - West Rain Garden Fort Collins, Colorado UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 1013-008_UD-BMP_v3.07 Rain Garden West.xlsm, RG 12/17/2020, 5:32 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? 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) Frederick S. Wegert Northern Engineering December 17, 2020 Homestead at Clarendon - West Rain Garden Fort Collins, Colorado 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 1013-008_UD-BMP_v3.07 Rain Garden West.xlsm, RG 12/17/2020, 5:32 PM Project: Date: Bottom Elevation:5088.6 533 ft3 Overflow Elevation:5089.7 572 ft3 Crest of Pond Elev.:5090.0 5089.6 Freeboard.:0.4 ft 1 ft Maximum Elevation Minimum Elevation cu. ft.acre ft cu. ft.acre ft 5088.6 N/A 430.0 0 0.0 0.00 0.0 0.00 5089.0 5088.6 493.3 0.4 184.7 0.00 184.7 0.00 5089.5 5089.0 570.0 0.5 265.8 0.01 450.5 0.01 5090.0 5089.5 647.2 0.5 304.3 0.01 754.8 0.02 Design Volume1: Volume at Overflow: Project Number: Project Location: Calculations By: Pond No.: Water Depth: West Rain Garden Stage Storage Curve Contour Contour Surface Area (ft2) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 1013-008 Fort Collins, Colorado F. Wegert West Rain Garden Elev at Design Volume: Homestead at Clarendon 12/18/2020 Pond Outlet and Volume Data Notes: 1) The MHFD spreadsheet UD-BMP is a password protected black box that prevents the user from multiplying the water quality volume by 120% per Fort Collins Stormwater Manual. Therefore, the Design Volume on this spreadsheet is 444 cu. ft. * 1.2. The 444 cu. ft. is the water quality volume from the UD - BMP. 12/17/2020 5:40 PM P:\1013-008\Drainage\LID\ 1013-008_Stage-Storage West.xlsx\Pond Project:Homestead at Clarendon Calc. By: Location:Fort Collins, Colorado Date: 39,434 sf 50% 19,717 sf 100% 39,434 sf 35,681 sf 90.5% 578 cf 603 cf 533 cf 572 cf 1111 cf 1175 cf 35,681 sf 90.5% 7,373 cf 7,373 cf 0.17 ac.-ft. 8,149 cf 0.19 ac.-ft. LID & Water Quality Summary F. Wegert 12/18/20 Project Summary LID Summary Total New Impervious Area Target LID Treatment Percentage Minimum Area to be Treated by LID measures Target Water Quality Treatment Percentage Detention Detention Treatment Area Minimum Area to be Treated by Water Quality measures Rain Gardens Rain Garden Treatment Area East Rain Garden Volume (Required) East Rain Garden Volume (Design) West Rain Garden Volume (Required) Percent Total Project Area Treated West Rain Garden Volume (Design) Total Rain Garden Volume (Required) Total Rain Garden Volume (Design) Water Quality Summary Percent Total Project Area Treated Storage Volume (Required) Total Detention Volume (Required) Total Detention Volume (Design) Project:Calc. By: Location:Date: Surface Area (SF)% Imperv.Imperv. Area (SF) Surface Area (SF)% Imperv.Imperv. Area (SF) Rooftop 0 100%0 Rooftop 25,025 90%22,523 Concrete 0 100%0 Concrete 0 100%0 Asphalt 0 100%0 Asphalt 13,158 100%13,158 Gravel 0 40%0 Gravel 9,384 40%3,754 Landscaping 142,798 0%0 Landscaping 95,231 0%0 Total 142,798 0 Total 142,798 39,434 39,434 Surface Area (SF)% Imperv.Imperv. Area (SF) Surface Area (SF)% Imperv.Imperv. Area (SF) Rooftop 25,025 90%22,523 Rooftop 25,025 90%22,523 Concrete 0 100%0 Concrete 0 100%0 Asphalt 13,158 100%13,158 Asphalt 13,158 100%13,158 Gravel 0 40%0 Gravel 0 40%0 Landscaping 0 0%0 Landscaping 0 0%0 35,681 35,681 Additional Impervious Area (SF) Existing Developed Onsite Impervious Area Onsite Impervious Areas Homestead at Clarendon Fort Collins, Colorado F. Wegert 12/18/20 Extended Detention Rain Gardens Total Total Developed Imperv. Area with LID TreatmentDeveloped Imperv. Area with WQ Treatment VAULTELECELECEEVAULTELECCONTROLIRR CONTROLIRR CONTROLIRR CONTROLIRR CONTROLIRR CONTROLIRR CONTROLIRR CONTROLIRR X X / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /CLARENDON HILLS DRIVELANGDALE DR IVEDETENTION PONDWEST RAIN GARDENREQUIRED VOLUME: 533 CU. FT.MINIMUM FLAT AREA: 325 SFPROVIDED VOLUME: 572 CU. FT.PROVIDED FLAT AREA: 430 SFTREATMENT AREA: 31,852 SFEAST RAIN GARDENREQUIRED VOLUME: 578 CU. FT.MINIMUM FLAT AREA: 353 SFPROVIDED VOLUME: 601 CU. FT.PROVIDED FLAT AREA: 603 SFTREATMENT AREA: 34,627 SFHOMESTEAD AT CLARENDON HILLSSHEET NO:P:\1013-008\DWG\DRNG\1013-008_LID.DWG301 N. Howes Street, Suite 100Fort Collins, Colorado 80521ENGINEERNGIEHTRONRNPHONE: 970.221.4158www.northernengineering.comDRAWING REFERENCE:LID TREATMENT EXHIBITF. Wegert1 in = 60 ftDecember 18, 2020LID-1DRAWN BY:SCALE:ISSUED:( IN FEET )01 INCH = 60 FEET6060LEGENDRAIN GARDEN TREATMENT AREAUNTREATED AREANOTES:1.UNTREATED AREA CONSISTS OF LANDSCAPING ANDLAWNS.2.RAIN GARDEN TREATMENT AREA CONSISTS OFAPPROXIMATELY SOUTH 3/4 OF LOTS (1 - 8), ROOFS,DRIVEWAYS, AND SHARED DRIVEWAY FOR LOTS 2 - 7.Homestead at Clarendon LID SummaryProject SummaryTotal New Impervious Area39,434sfTarget Treatment Percentage50%Minimum Area to be Treated by LID measures19,717sfRain GardensTotal Rain Garden Treatment Area35,681sfTotal Treatment Area35,681sfPercent Total Project Area Treated90.5% ATTACHMENT 4 PREVIOUS REPORT EXCERPTS This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA Excerpts from Clarendon Hills 1st Filing Drainage Report This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA Excerpts from Clarendon Hills 4th Filing Drainage Report This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA Excerpts from Clarendon Hills 6th Filing Drainage Report This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Nov-02-2018 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA ATTACHMENT 5 USDA NRCS SOILS REPORT United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado Homestead at Clarendon Hills Natural Resources Conservation Service April 5, 2019 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Larimer County Area, Colorado......................................................................13 4—Altvan-Satanta loams, 3 to 9 percent slopes.........................................13 56—Kim-Thedalund loams, 3 to 15 percent slopes....................................15 74—Nunn clay loam, 1 to 3 percent slopes.................................................17 Soil Information for All Uses...............................................................................19 Soil Properties and Qualities..............................................................................19 Soil Erosion Factors........................................................................................19 Wind Erodibility Index..................................................................................19 Soil Qualities and Features.............................................................................22 Hydrologic Soil Group.................................................................................22 References............................................................................................................27 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 448531044853304485350448537044853904485410448543044854504485470448531044853304485350448537044853904485410448543044854504485470491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 40° 31' 11'' N 105° 5' 46'' W40° 31' 11'' N105° 5' 34'' W40° 31' 6'' N 105° 5' 46'' W40° 31' 6'' N 105° 5' 34'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,260 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 20, 2015—Oct 21, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 4 Altvan-Satanta loams, 3 to 9 percent slopes 0.4 10.5% 56 Kim-Thedalund loams, 3 to 15 percent slopes 3.4 89.2% 74 Nunn clay loam, 1 to 3 percent slopes 0.0 0.2% Totals for Area of Interest 3.8 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or Custom Soil Resource Report 11 landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Larimer County Area, Colorado 4—Altvan-Satanta loams, 3 to 9 percent slopes Map Unit Setting National map unit symbol: jpwf Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Farmland of statewide importance Map Unit Composition Altvan and similar soils: 55 percent Satanta and similar soils: 35 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: Fans, benches, terraces Landform position (three-dimensional): Base slope, side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 16 inches: clay loam, loam, sandy clay loam H2 - 9 to 16 inches: loam, fine sandy loam, silt loam H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 16 to 31 inches: H3 - 16 to 31 inches: H3 - 16 to 31 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: Properties and qualities Slope: 6 to 9 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 13.7 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Custom Soil Resource Report 13 Hydrologic Soil Group: B Hydric soil rating: No Description of Satanta Setting Landform: Terraces, structural benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 14 inches: loam, clay loam, sandy clay loam H2 - 9 to 14 inches: loam, clay loam, fine sandy loam H2 - 9 to 14 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: Properties and qualities Slope: 3 to 6 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No Minor Components Nunn Percent of map unit: 6 percent Hydric soil rating: No Larimer Percent of map unit: 4 percent Hydric soil rating: No Custom Soil Resource Report 14 56—Kim-Thedalund loams, 3 to 15 percent slopes Map Unit Setting National map unit symbol: jpx0 Elevation: 4,800 to 5,600 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Not prime farmland Map Unit Composition Kim and similar soils: 45 percent Thedalund and similar soils: 35 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Kim Setting Landform: Valley sides, fans Landform position (three-dimensional): Side slope, base slope Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 7 inches: loam H2 - 7 to 60 inches: loam, clay loam, sandy clay loam H2 - 7 to 60 inches: H2 - 7 to 60 inches: Properties and qualities Slope: 3 to 7 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm) Available water storage in profile: Very high (about 26.5 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Custom Soil Resource Report 15 Ecological site: Loamy Plains (R067XY002CO) Hydric soil rating: No Description of Thedalund Setting Landform position (three-dimensional): Side slope Down-slope shape: Linear Across-slope shape: Linear Parent material: Material weathered from sandstone and shale Typical profile H1 - 0 to 4 inches: loam H2 - 4 to 33 inches: clay loam, loam, sandy clay loam H2 - 4 to 33 inches: weathered bedrock H2 - 4 to 33 inches: H3 - 33 to 37 inches: Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: 20 to 40 inches to paralithic bedrock Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to high (0.06 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to moderately saline (0.0 to 8.0 mmhos/cm) Available water storage in profile: Very high (about 15.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6e Hydrologic Soil Group: C Ecological site: Loamy Plains (R067XY002CO) Hydric soil rating: No Minor Components Renohill Percent of map unit: 10 percent Hydric soil rating: No Midway Percent of map unit: 9 percent Hydric soil rating: No Aquic haplustolls Percent of map unit: 1 percent Landform: Swales Hydric soil rating: Yes Custom Soil Resource Report 16 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlpl Elevation: 3,900 to 5,840 feet Mean annual precipitation: 13 to 17 inches Mean annual air temperature: 50 to 54 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 9 inches: clay loam Bt - 9 to 13 inches: clay loam Btk - 13 to 25 inches: clay loam Bk1 - 25 to 38 inches: clay loam Bk2 - 38 to 80 inches: clay loam Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 7 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.9 inches) Interpretive groups Land capability classification (irrigated): 2e Custom Soil Resource Report 17 Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: Clayey Plains (R067BY042CO) Hydric soil rating: No Minor Components Heldt Percent of map unit: 10 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: Clayey Plains (R067BY042CO) Hydric soil rating: No Satanta Percent of map unit: 5 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: Loamy Plains (R067BY002CO) Hydric soil rating: No Custom Soil Resource Report 18 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Erosion Factors Soil Erosion Factors are soil properties and interpretations used in evaluating the soil for potential erosion. Example soil erosion factors can include K factor for the whole soil or on a rock free basis, T factor, wind erodibility group and wind erodibility index. Wind Erodibility Index The wind erodibility index is a numerical value indicating the susceptibility of soil to wind erosion, or the tons per acre per year that can be expected to be lost to wind erosion. There is a close correlation between wind erosion and the texture of the surface layer, the size and durability of surface clods, rock fragments, organic matter, and a calcareous reaction. Soil moisture and frozen soil layers also influence wind erosion. 19 20 Custom Soil Resource Report Map—Wind Erodibility Index 448531044853304485350448537044853904485410448543044854504485470448531044853304485350448537044853904485410448543044854504485470491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 40° 31' 11'' N 105° 5' 46'' W40° 31' 11'' N105° 5' 34'' W40° 31' 6'' N 105° 5' 46'' W40° 31' 6'' N 105° 5' 34'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,260 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons 0 38 48 56 86 134 160 180 220 250 310 Not rated or not available Soil Rating Lines 0 38 48 56 86 134 160 180 220 250 310 Not rated or not available Soil Rating Points 0 38 48 56 86 134 160 180 220 250 310 Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 20, 2015—Oct 21, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 21 Table—Wind Erodibility Index Map unit symbol Map unit name Rating (tons per acre per year) Acres in AOI Percent of AOI 4 Altvan-Satanta loams, 3 to 9 percent slopes 56 0.4 10.5% 56 Kim-Thedalund loams, 3 to 15 percent slopes 86 3.4 89.2% 74 Nunn clay loam, 1 to 3 percent slopes 48 0.0 0.2% Totals for Area of Interest 3.8 100.0% Rating Options—Wind Erodibility Index Units of Measure: tons per acre per year Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Hydrologic Soil Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Custom Soil Resource Report 22 Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Custom Soil Resource Report 23 24 Custom Soil Resource Report Map—Hydrologic Soil Group 448531044853304485350448537044853904485410448543044854504485470448531044853304485350448537044853904485410448543044854504485470491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 491850 491870 491890 491910 491930 491950 491970 491990 492010 492030 492050 492070 492090 492110 40° 31' 11'' N 105° 5' 46'' W40° 31' 11'' N105° 5' 34'' W40° 31' 6'' N 105° 5' 46'' W40° 31' 6'' N 105° 5' 34'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,260 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 20, 2015—Oct 21, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 25 Table—Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 4 Altvan-Satanta loams, 3 to 9 percent slopes B 0.4 10.5% 56 Kim-Thedalund loams, 3 to 15 percent slopes B 3.4 89.2% 74 Nunn clay loam, 1 to 3 percent slopes C 0.0 0.2% Totals for Area of Interest 3.8 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Custom Soil Resource Report 26 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 27 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 28 ATTACHMENT 6 DRAINAGE EXHIBITS VAULTELECELECEEVAULTELECCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRX X X X X / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /CLARENDON HILLS DRIVELANGDA LE DR IVE FRONT RANGECOMMUNITY COLLEGECLARENDON HILLSFIRST FILINGEX B0.68 acEX A2.38 acEX OS10.15 acEX OS20.06 acEX BEX AEX OS2EX OS1SMITH LATERALEXISTING PRIVATELY OWNEDIRRIGATION DITCH (SEE NOTE 2)DR1HISTORIC DRAINAGE EXHIBIT17CALL 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.Feet03030306090SheetHOMESTEAD AT CLARENDON HILLS These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc.NOT FOR CO N S T R U C T I O N REVIEW SE T E N G I N E E R N GI EHTRON R N FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.comof 18LEGEND:ADESIGN POINTFLOW ARROWDRAINAGE BASIN LABELEXISTING DRAINAGE BASIN BOUNDARYFOR DRAINAGE REVIEW ONLYNOT FOR CONSTRUCTIONCPROPOSED CONTOUREXISTING CONTOURPROPERTY BOUNDARYPROPOSED STORM DRAIN / IRRIGATIONEXISTING CURB AND GUTTERPROPOSED SWALEPROPOSED LOT LINEEASEMENTEXISTING DRAINAGE SUMMARYDesignPointBasin IDTotalArea(acres)C2C1002-Yr Tc(min)100-Yr Tc(min)Q2(cfs)Q100(cfs)ex aEX A2.3820.250.3114.0614.061.145.00bEX B0.6840.250.3112.0612.060.351.53bEX OS10.1470.250.3111.0811.080.080.34bEX OS20.0640.250.315.425.420.050.20NOTES:1.REFER TO THE FINAL DRAINAGE LETTER FOR HOMESTEAD AT CLARENDON HILLS FOR ADDITIONALINFORMATION.2.THE SMITH LATERAL IS OWNED BY NUMEROUS INDIVIDUAL OWNERS AS WELL AS THE CITY OF FORTCOLLINS (THROUGH THE PARKS DEPARTMENT) WHO USE THE DITCH TO CONVEY IRRIGATIONWATER. APPROVAL FROM THE IRRIGATION DITCH OWNERS IS REQUIRED PRIOR TO ANY WORK ONTHE DITCH OR IN ITS EASEMENT, AS WELL AS BEFORE ANY STORMWATER CAN BE DISCHARGED, ORPLANNED TO BE DISCHARGED INTO THE DITCH. PLEASE CONTACT JILL WUERTZ (970-416-2062), 413 S.BRYAN AVE, FORT COLLINS, CO 80521 REGARDING THE PARKS' DEPARTMENT'S INTEREST.BENCHMARKPROJECT DATUM: NAVD88CITY OF FORT COLLINS BENCHMARK 5-021/2 MILE SOUTH OF HARMONY ROAD, APPROXIMATELY 200 FEET NORTH OF WOODED CREEK COURT, ONTHE WEST SIDE OF SHIELDS STREET, ON THE NORTHWEST CORNER OF A STORM INLET.ELEV. = 5089.11CITY OF FORT COLLINS BENCHMARK 8-13SOUTHEAST CORNER OF HARMONY RD. AND SHIELDS ON THE NORTHEAST CORNER OF A CONCRETETRAFFIC SIGNAL BASE.ELEV. = 5086.71PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTSHAVE USED NGVD29 UNADJUSTED (PRIOR CITY OF FORT COLLINS DATUM) FOR THEIR VERTICAL DATUMS.IF NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) IS REQUIRED FOR ANY PURPOSE,THE FOLLOWING EQUATION SHOULD BE USED:NGVD29 UNADJUSTED (PRIOR CITY OF FORT COLLINS DATUM) = NAVD88 - 3.20'BASIS OF BEARINGSTHE BASIS OF BEARINGS IS THE WEST LINE OF SECTION 2-6-69 AS BEARING NORTH 00° 17' 10" EAST(ASSUMED BEARING). CONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRRX X X X X / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /LANGDA LE DR IVE ACCESS EASEMENTLOT 6LOT 7LOT 8B30.01 acOS10.09 acAOS1PROPOSED RAINGARDEN WITH FOREBAYPROPOSED OUTLET STRUCTURECONSTRUCTED AS PART OF WALLPROPOSED SIDEWALK CULVERTPROPOSEDTRENCH DRAINPROPOSEDDRIVEWAY CULVERTUNDERDRAINVAULTELECELECEEVAULTELECCONTROLIRRCONTROLIRRCONTROLIRRCONTROLIRR/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /CLARENDON HILLS DRIVEFRONT RANGECOMMUNITY COLLEGECLARENDON HILLSFIRST FILINGLOT 1LOT 2LOT 3LOT 5LOT 4TRACT AA1.37 ac/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /B10.04 acB21.63 acB40.01 acOS20.06 acPROPOSED DRIVEWAYPROPOSED PONDWSE - 5089.41BTRACT BDITCH ACCESS EASEMENT(WIDTH VARIES - SEE NOTE 2)SMITH LATERALEXISTING PRIVATELY OWNEDIRRIGATION DITCH (SEE NOTE 2)UDUDPROPOSED RAIN GARDEN WITH FOREBAYPROPOSED RETAINING WALL(RE: LANDSCAPE ARCHITECT)PROPOSED VERTICALCURB & GUTTERPROPOSED OUTLET STRUCTURECONSTRUCTED AS PART OF WALLPROPOSED SIDEWALK CULVERTWITH CONCRETE CHASEPROPOSED OUTLET PIPEPROPOSED VALLEY PANPOND OVERFLOW /SPILLWAY ELEV. = 5089.80UNDERDRAINPROVIDE WEIR IN RETAINING WALL AT ELEV.5089.7 TO ALLOW EMERGENCY FLOWS FROMPOND TO SPILL INTO RAIN GARDEN.ELEV. AT CURB CUT = 5089.59 TO ALLOWEMERGENCY SPILLS TO FLOW INTO CURBDR2PROPOSED DRAINAGE EXHIBIT18CALL 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.Feet03030306090SheetHOMESTEAD AT CLARENDON HILLS These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc.NOT FOR CO N S T R U C T I O N REVIEW SE T E N G I N E E R N GI EHTRON R N FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.comof 18LEGEND:ADESIGN POINTFLOW ARROWDRAINAGE BASIN LABELNOTES:1.REFER TO THE FINAL DRAINAGE LETTER FOR HOMESTEAD AT CLARENDON HILLS FOR ADDITIONALINFORMATION.2.THE SMITH LATERAL IS OWNED BY NUMEROUS INDIVIDUAL OWNERS AS WELL AS THE CITY OF FORTCOLLINS (THROUGH THE PARKS DEPARTMENT) WHO USE THE DITCH TO CONVEY IRRIGATIONWATER. APPROVAL FROM THE IRRIGATION DITCH OWNERS IS REQUIRED PRIOR TO ANY WORK ONTHE DITCH OR IN ITS EASEMENT, AS WELL AS BEFORE ANY STORMWATER CAN BE DISCHARGED, ORPLANNED TO BE DISCHARGED INTO THE DITCH. PLEASE CONTACT JILL WUERTZ (970-416-2062), 413 S.BRYAN AVE, FORT COLLINS, CO 80521 REGARDING THE PARKS' DEPARTMENT'S INTEREST.BENCHMARKFOR DRAINAGE REVIEW ONLYNOT FOR CONSTRUCTIONCPROJECT DATUM: NAVD88CITY OF FORT COLLINS BENCHMARK 5-021/2 MILE SOUTH OF HARMONY ROAD, APPROXIMATELY 200 FEET NORTH OF WOODED CREEK COURT, ONTHE WEST SIDE OF SHIELDS STREET, ON THE NORTHWEST CORNER OF A STORM INLET.ELEV. = 5089.11CITY OF FORT COLLINS BENCHMARK 8-13SOUTHEAST CORNER OF HARMONY RD. AND SHIELDS ON THE NORTHEAST CORNER OF A CONCRETETRAFFIC SIGNAL BASE.ELEV. = 5086.71PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTSHAVE USED NGVD29 UNADJUSTED (PRIOR CITY OF FORT COLLINS DATUM) FOR THEIR VERTICAL DATUMS.IF NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) IS REQUIRED FOR ANY PURPOSE,THE FOLLOWING EQUATION SHOULD BE USED:NGVD29 UNADJUSTED (PRIOR CITY OF FORT COLLINS DATUM) = NAVD88 - 3.20'BASIS OF BEARINGSTHE BASIS OF BEARINGS IS THE WEST LINE OF SECTION 2-6-69 AS BEARING NORTH 00° 17' 10" EAST(ASSUMED BEARING).PROPOSED CONTOUREXISTING CONTOURPROPERTY BOUNDARYPROPOSED STORM DRAIN / IRRIGATIONEXISTING CURB AND GUTTERPROPOSED SWALEPROPOSED LOT LINEEASEMENTDEVELOPED DRAINAGE SUMMARYDesignPointBasin IDTotalArea(acres)C2C1002-Yr Tc(min)100-Yr Tc(min)Q2(cfs)Q100(cfs)aA1.3680.240.3014.2514.250.632.74bB10.0410.290.3612.0312.030.020.10bB21.6300.600.7512.7412.741.988.65bB30.0130.200.2512.2612.260.010.02bB40.0700.250.3111.0411.040.040.16os1OS10.0920.460.5710.8910.890.090.40os2OS20.0640.250.315.005.000.050.20Detention Pond and Rain Garden SummaryDescriptionRequiredVolume(cu. ft.)DesignVolume(cu. ft.)Release Rate(cfs)Crest of PondElev.WaterSurface Elev.Freeboard(ft)Detention Pond9,4759,8071.25090.65089.750.85East Rain Garden297297n/a5090.65089.90.7West Rain Garden297297n/a5090.65089.70.9EXISTING DRAINAGE SUMMARYDesignPointBasin IDTotalArea(acres)C2C1002-Yr Tc(min)100-Yr Tc(min)Q2(cfs)Q100(cfs)ex aEX A2.3820.250.3114.0614.061.145.00bEX B0.6840.250.3112.0612.060.351.53bEX OS10.1470.250.3111.0811.080.080.34bEX OS20.0640.250.315.425.420.050.20PROPOSED DRAINAGE BASIN BOUNDARY50' WETLANDS BUFFERLID & WATER QUALITY SUMMARYProject SummaryTotal New Impervious Area 39,434sfTarget LID Treatment Percentage50%Minimum Area to be Treated by LID measures19,717sfTarget Water Quality Treatment Percentage100%Minimum Area to be Treated by Water Quality measures39,434sfLID SummaryRain GardensRain Garden Treatment Area35,681sfPercent Total Project Area Treated90.5%East Rain Garden Volume (Required)297cfEast Rain Garden Volume (Design)273cfWest Rain Garden Volume (Required)297cfWest Rain Garden Volume (Design)321cfTotal Rain Garden Volume (Required)594cfTotal Rain Garden Volume (Design)594cfWater Quality SummaryDetentionDetention Treatment Area35,681sfPercent Total Project Area Treated90.5%Water Quality Volume (Required)1,187cfStorage Volume (Required)8,288cfTotal Detention Volume (Required)9,475cf0.22ac.-ft.Total Detention Volume (Design)9,807cf0.23ac.-ft.POND INUNDATION AREAEMERGENCY OVERFLOW PATH