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Home My WebLink AboutHOMESTEAD AT CLARENDON HILLS - PDP190007 - SUBMITTAL DOCUMENTS - ROUND 3 - DRAINAGE REPORTAugust 14, 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: August 14, 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. All proposed roof drains will drain south to the proposed detention area. Basin B is further subdivided into Basins B1, B2, B3, and B4. Basins B1 and B3 consists of the two lots (Lots 1 and 8) at the west and east ends, and Basins B1 and B3 will discharge into the Clarendon Hills and Langdon Drives curb and gutter. Basin B2 consists of the Lots 2 through 7 and driveways and discharge into 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. 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 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. Page | 4 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 0.3 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.) 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 City LID requirements specify that 50% of all single-family areas and 75% of all new impervious area receive water quality treatment from a LID facility. This project proposes to treat 79.8% of the new impervious areas through two rain gardens and a grass buffer. The rain gardens will also provide water quality treatment for the project site. A vegetated buffer will be located between the rear lot lines and the irrigation ditch. The ditch access road limits the available native land to be used as a vegetated buffer. An exhibit showing the area of LID treatment is included in the appendices. Although exact impervious area is unavailable at this preliminary stage, the majority of the residential area will drain towards the rain gardens or across the vegetated buffer. The front 2/3rds of the lot will be graded to drain south towards the rain gardens. The rear 1/3rd of the lot will be graded to drain towards the vegetated buffer. The high point along each lot line is set to maximize as much of the lot that drains towards the rain gardens as possible. 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 0.8 cfs less than the existing flowrate. Page | 5 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 Character of Surface Runoff Coefficient1 Percent Impervious1 0.95 100% 0.95 90% 0.50 40% 0.55 50% 0.20 2% 0.25 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, Avg Slope 2- 7% (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 2% 0.25 0.25 0.25 0.31 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% USDA SOIL TYPE: B Undeveloped: Greenbelts, Agriculture 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% 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. Combined and Routed Basins HISTORIC RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Gravel Residential: Low Density Homestead at Clarendon F. Wegert Project: Calculations By: Date: C2*Cf C10*Cf C100*Cf 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) Tc 2-Yr (min) Tc 10-Yr (min) Tc 100-Yr (min) ex a EX A 0.25 0.25 0.31 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% 0.10 108.93 14.06 14.06 14.06 ex b EX B 0.25 0.25 0.31 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 7.41 7.01 ex os1 EX OS1 0.25 0.25 0.31 195 93.00 86.13 3.52% 14.6 14.6 13.5 N/A N/A N/A N/A N/A N/A 11.08 11.08 11.08 ex os2 EX OS2 0.25 0.25 0.31 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 5.42 5.02 ex a North 0.25 0.25 0.31 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% 0.10 108.93 14.06 14.06 14.06 Gutter/Swale Flow, Time of Concentration: 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 14.06 14.06 14.06 0.25 0.25 0.31 1.92 3.29 6.71 1.1 2.0 5.0 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 11.08 0.25 0.25 0.31 2.13 3.63 7.42 0.1 0.1 0.3 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 14.06 0.25 0.25 0.31 1.92 3.29 6.71 1.2 2.1 5.4 Homestead at Clarendon F. Wegert August 5, 2020 Project: Gutter/Swale Flow, Time of Concentration: Calculations By: Date: Combined and Routed Basins HISTORIC DIRECT RUNOFF COMPUTATIONS Intensity Flow Overland Flow, Time of Concentration: Intensity, I from Fig. RA-2 Rational Equation: Q = CiA (Equation 6-1 per MHFD) Design Point Basin Area (acres) Tc (Min) Runoff C Tt = L / 60V (Equation 6-4 per MHFD) Tc = Ti + Tt (Equation 6-2 per MHFD) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ (Equation 6-4 per MHFD) (Equation 6-3 per MHFD) } 𝑇𝑖 = 1.87 1.1 − 𝐶 ∗ 𝐶𝑓 𝐿 𝑆 ൗ 1 3 Page 3 of 3 Character of Surface Runoff Coefficient1 Percent Impervious1 0.95 100% 0.95 90% 0.50 40% 0.55 50% 0.20 2% 0.25 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, Avg Slope 2- 7% (acres) Percent Impervious C2*Cf Cf = 1.00 C5*Cf Cf = 1.00 C10*Cf Cf = 1.00 C100*Cf Cf = 1.25 A 67,789 1.556 0.000 0.000 0.176 0.338 1.043 0.000 17% 0.31 0.31 0.31 0.39 B1 7,111 0.163 0.000 0.000 0.012 0.123 0.000 0.029 41% 0.49 0.49 0.49 0.62 B2 52,848 1.213 0.149 0.000 0.000 0.902 0.000 0.162 50% 0.56 0.56 0.56 0.70 B3 3,897 0.089 0.000 0.000 0.000 0.082 0.000 0.007 46% 0.53 0.53 0.53 0.66 B4 3,034 0.070 2% 0.25 0.25 0.25 0.31 OS1 5,313 0.122 0.000 0.000 0.028 0.044 0.050 0.000 28% 0.40 0.40 0.40 0.49 OS2 2,806 0.064 2% 0.25 0.25 0.25 0.31 North 75,907 1.743 0.000 0.000 0.203 0.382 1.157 0.000 17% 0.31 0.31 0.31 0.39 South 66,891 1.536 0.149 0.000 0.012 1.107 0.000 0.268 46% 0.54 0.54 0.54 0.67 DEVELOPED RUNOFF COEFFICIENT CALCULATIONS Asphalt, Concrete Rooftop Gravel Residential: Low Density Homestead at Clarendon F. Wegert August 5, 2020 Project: Calculations By: Date: 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. Project: Calculations By: Date: C2*Cf C10*Cf C100*Cf 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) Tc 2-Yr (min) Tc 10-Yr (min) Tc 100-Yr (min) a A 0.31 0.31 0.39 60 92.89 89.01 6.47% 6.1 6.1 5.5 N/A N/A N/A 705 89.01 85.49 0.50% 0.11 110.86 14.25 14.25 14.25 b B1 0.49 0.49 0.62 40 93.97 92.33 4.10% 4.5 4.5 3.6 326 92.33 84.93 2.27 3.01 1.80 N/A N/A N/A 6.28 6.28 5.37 b B2 0.56 0.56 0.70 95 94.23 92.41 1.92% 7.9 7.9 5.9 350 92.41 84.93 2.14 2.92 2.00 N/A N/A N/A 9.93 9.93 7.88 b B3 0.53 0.53 0.66 60 93.10 91.71 2.32% 6.3 6.3 4.8 305 91.71 84.93 2.22 2.98 1.70 N/A N/A N/A 7.99 7.99 6.55 b B4 0.25 0.25 0.31 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 5.00 5.00 5.00 os1 OS1 0.40 0.40 0.49 160 93.83 93.10 0.46% 21.7 21.7 18.6 N/A N/A N/A N/A N/A N/A 10.89 10.89 18.62 Tc2 Tc10 Tc100 C2 C10 C100 I2 (in/hr) I10 (in/hr) I100 (in/hr) Q2 (cfs) Q10 (cfs) Q100 (cfs) a A 1.556 14.25 14.25 14.25 0.31 0.31 0.39 1.92 3.29 6.71 0.9 1.6 4.0 b B1 0.163 6.28 6.28 5.37 0.49 0.49 0.62 2.67 4.56 9.31 0.2 0.4 0.9 b B2 1.213 9.93 9.93 7.88 0.56 0.56 0.70 2.26 3.86 7.88 1.5 2.6 6.7 b B3 0.089 7.99 7.99 6.55 0.53 0.53 0.66 2.46 4.21 8.59 0.1 0.2 0.5 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 0.122 10.89 10.89 18.62 0.40 0.40 0.49 2.17 3.71 7.57 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 1.743 14.25 14.25 116.38 0.31 0.31 0.39 1.92 3.29 6.71 1.0 1.8 4.6 b South 1.536 10.27 10.27 8.30 0.54 0.54 0.67 2.21 3.78 7.72 1.8 3.1 7.9 Gutter/Swale Flow, Time of Concentration: Project: Calculations By: Date: Homestead at Clarendon F. Wegert August 5, 2020 Combined and Routed Basins DEVELOPED DIRECT RUNOFF COMPUTATIONS Intensity Flow Overland Flow, Time of Concentration: Intensity, I from Fig. RA-2 Rational Equation: Q = CiA (Equation 6-1 per MHFD) Design Point Basin Area (acres) Tc (Min) Runoff C Tt = L / 60V (Equation 6-4 per MHFD) Tc = Ti + Tt (Equation 6-2 per MHFD) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ (Equation 6-4 per MHFD) (Equation 6-3 per MHFD) } 𝑇𝑖 = 1.87 1.1 − 𝐶 ∗ 𝐶𝑓 𝐿 𝑆 ൗ 1 3 Page 3 of 3 ATTACHMENT 2 DETENTION POND CALCULATIONS WATER QUALITY CALCULATIONS LID CALCULATIONS AND EXHIBIT Pond No : B2 100-yr 0.70 7.88 min 9091 ft3 1.21 acres 0.21 ac-ft Max Release Rate = 0.30 cfs 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 2535 1.00 0.30 90 2445 10 7.720 3934 1.00 0.30 180 3754 15 6.520 4983 1.00 0.30 270 4713 20 5.600 5707 1.00 0.30 360 5347 25 4.980 6344 1.00 0.30 450 5894 30 4.520 6910 1.00 0.30 540 6370 35 4.080 7276 1.00 0.30 630 6646 40 3.740 7623 1.00 0.30 720 6903 45 3.460 7934 1.00 0.30 810 7124 50 3.230 8229 1.00 0.30 900 7329 55 3.030 8492 1.00 0.30 990 7502 60 2.860 8744 1.00 0.30 1080 7664 65 2.720 9009 1.00 0.30 1170 7839 70 2.590 9238 1.00 0.30 1260 7978 75 2.480 9478 1.00 0.30 1350 8128 80 2.380 9702 1.00 0.30 1440 8262 85 2.290 9918 1.00 0.30 1530 8388 90 2.210 10135 1.00 0.30 1620 8515 95 2.130 10311 1.00 0.30 1710 8601 100 2.060 10497 1.00 0.30 1800 8697 105 2.000 10701 1.00 0.30 1890 8811 110 1.940 10874 1.00 0.30 1980 8894 115 1.890 11075 1.00 0.30 2070 9005 120 1.840 11251 1.00 0.30 2160 9091 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. A = Tc = Project Location : Design Point C = Design Storm DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado Project Number: Project Name: Project Location: Basin Notes Historic Basin EX A 5.0 cfs Historic Basin EX OS1 0.3 cfs Historic Basin EX OS2 0.2 cfs Total Q100 to the North 5.5 cfs Proposed Basin A 4.0 cfs Proposed Basin OS1 0.5 cfs Proposed Basin OS2 0.2 cfs Total Q100 to the North 4.7 cfs Change in Q100 to the North 0.8 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 0.9 cfs Proposed Basin B3 0.5 cfs Proposed Basin B4 0.2 cfs Detention Pond Release Rate 0.3 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 Project: Date: Outlet Elevation: 5086.64 0.210 ac. ft. Grate Elevation: 5089.6 0.210 ac. ft. Crest of Pond Elev.: 5090.6 5089.58 Freeboard.: 1.0 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 5086.6 860.2 0.4 154.8 0.00 154.8 0.00 5087.5 5087.0 3,075.6 0.5 984.0 0.02 1,138.8 0.03 5088.0 5087.5 3,731.4 0.5 1,701.7 0.04 2,840.6 0.07 5088.5 5088.0 3,924.2 0.5 1,913.9 0.04 4,754.4 0.11 5089.0 5088.5 4,062.6 0.5 1,996.7 0.05 6,751.1 0.15 5089.5 5089.0 4,148.5 0.5 2,052.8 0.05 8,803.9 0.20 5090.0 5089.5 4,215.6 0.5 2,091.0 0.05 10,894.9 0.25 5090.6 5090.0 4,289.6 0.6 2,551.5 0.06 13,446.5 0.31 Volume at Grate: Project Number: Project Location: Calculations By: Pond No.: Detention Pond Stage Storage Curve Contour Contour Surface Area (ft 2 ) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 1013-008 Fort Collins, Colorado F. Wegert B2 Elev at Design Volume: Homestead at Clarendon 8/5/2020 Pond Outlet and Volume Data Design Volume: 8/4/2020 5:20 PM P:\1013-008\Drainage\Detention\ 1013-008_Stage-Storage.xlsx\Pond Broad-Crested Weir: Project: Homestead at Clarendon Project # 1013-008 Governing Equations: Q= 0.385CL√2g H3/2 * where Q is flow rate in CFS * where C is ratio of actual discharge to theoretical discharge. A value of C can be obtained from Figure 4-36 of Reference 1. * where L is the crest length of the weir (FT) * where H is the height of flow over the crest (FT) * where P is the vertical distance from weir crest to pond\channel invert (FT) Valid if 0.1<H/L<0.8 Input Parameters: Length (L)= 20.00 FT Crest Elevation = 5089.60 FT Upsteam Invert Elevation= 5086.64 FT Depth vs. Flow: Depth Above Crest (ft) Elevation (ft) H/(H+P) C Flow (cfs) 0.00 5089.60 0.00 0.87 0.00 0.10 5089.70 0.03 0.86 1.68 0.20 5089.80 0.06 0.86 4.74 0.26 5089.86 0.08 0.86 7.02 Q100 0.40 5090.00 0.12 0.86 13.39 0.50 5090.10 0.14 0.86 18.73 0.60 5090.20 0.17 0.86 24.66 0.70 5090.30 0.19 0.86 31.14 0.80 5090.40 0.21 0.86 38.14 0.90 5090.50 0.23 0.86 45.62 Q100 = 6.7 CFS (100-Year Storm) If the weir is long in the direction of flow so that the flow leaves the weir in essentially a horizontal direction, the weir is a broad- crested weir. Reference 1) "Hydraulic Engineering, Roberson, Cassidy & Chaudhry., John Wiley & Sons, 1995, pg 212)" 0.85 0.9 0.95 1 1.05 0 0.2 0.4 0.6 0.8 1 C H/(H+P) Broad-Crested Weir Coefficient (C) Project: Calc. By: Date: 1.213 <-- INPUT from impervious calcs 50.00 <-- INPUT from impervious calcs 0.5000 <-- CALCULATED 12 hours <-- from MHFD Vol. 3 Table 3-2 0.8 <-- from MHFD Vol. 3 Table 3-2 0.165 <-- MHFD Vol. 3 Equation 3-1 0.017 <-- MHFD Vol. 3 Equation 3-3 727 <-- MHFD Vol. 3 Equation 3-3 ** <-- INPUT from stage-storage table ** <-- CALCULATED from Figure EDB-3 dia (in) = ** <-- INPUT from Figure 5 n = ** <-- INPUT from Figure 5 t (in) = ** <-- INPUT from Figure 5 number of rows = ** <-- from WQ Depth and row spacing August 5, 2020 WQCV (ft3) = WATER QUALITY POND DESIGN CALCULATIONS Primary Pond Required Storage & Outlet Works Homestead at Clarendon F. Wegert Circular Perforation Sizing **To be completed at final design Basin Area = Basin Percent Imperviousness = Basin Imperviousness Ratio = WQCV (watershed inches) = WQCV (ac-ft) = WQ Depth (ft) = Area Required Per Row, a (in2) = Drain Time Coefficient = Drain Time = Project: Date: Bottom Elevation: 5089.1 364 ft 3 Overflow Elevation: 5090.1 348 ft 3 Crest of Pond Elev.: 5090.6 5090.13 Freeboard.: 0.5 ft Maximum Elevation Minimum Elevation cu. ft. acre ft cu. ft. acre ft 5089.1 N/A 0.0 0 0.0 0.00 0.0 0.00 5089.5 5089.1 377.9 0.4 75.6 0.00 75.6 0.00 5090.0 5089.5 482.8 0.5 215.2 0.00 290.7 0.01 5090.6 5090.0 656.3 0.6 341.7 0.01 632.4 0.01 Rain Garden Stage Storage Curve Contour Contour Surface Area (ft 2 ) 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 8/5/2020 Pond Outlet and Volume Data Design Volume: Volume at Overflow: Project Number: Project Location: Calculations By: Pond No.: 8/4/2020 5:49 PM P:\1013-008\Drainage\WatQual\ 1013-008_Stage-Storage East.xlsx\Pond Project: Date: Bottom Elevation: 5088.6 364 ft 3 Overflow Elevation: 5089.6 316 ft 3 Crest of Pond Elev.: 5090.0 5089.70 Maximum Elevation Minimum Elevation cu. ft. acre ft cu. ft. acre ft 5088.6 N/A 0.0 0 0.0 0.00 0.0 0.00 5089.0 5088.6 358.8 0.4 71.8 0.00 71.8 0.00 5089.5 5089.0 431.8 0.5 197.7 0.00 269.4 0.01 5090.0 5089.5 509.8 0.5 235.4 0.01 504.8 0.01 Volume at Overflow: Project Number: Project Location: Calculations By: Pond No.: West Rain Garden Stage Storage Curve Contour Contour Surface Area (ft 2 ) 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 8/5/2020 Pond Outlet and Volume Data Design Volume: 8/4/2020 5:50 PM P:\1013-008\Drainage\WatQual\ 1013-008_Stage-Storage West.xlsx\Pond Project: Calc. By: Location: Date: Surface Area (SF) % Imperv. Imperv. Area (SF) Surface Area (SF) % Imperv. Imperv. Area (SF) Res. Low Density 0 100% 0 Res. Low Density 64,872 50% 32,436 Concrete 0 100% 0 Concrete 0 100% 0 Asphalt 0 100% 0 Asphalt 6,485 100% 6,485 Gravel 0 40% 0 Gravel 9,384 40% 3,754 Landscaping 142,798 0% 0 Landscaping 62,057 0% 0 Total 142,798 0 Total 142,798 42,675 42,675 Surface Area (SF) % Imperv. Imperv. Area (SF) Surface Area (SF) % Imperv. Imperv. Area (SF) Res. Low Density 15,794 50% 7,897 Res. Low Density 39,304 50% 19,652 Concrete 0 100% 0 Concrete 0 100% 0 Asphalt 0 100% 0 Asphalt 6,485 100% 6,485 Gravel 0 40% 0 Gravel 0 40% 0 Landscaping 0 0% 0 Landscaping 0 0% 0 7,897 26,137 Developed Impervious Area with LID Treatment Vegetated Buffers Rain Gardens Total Total Additional Impervious Area (SF) Existing Developed Onsite Impervious Area Onsite Impervious Areas Homestead at Clarendon Fort Collins, Colorado F. Wegert 08/05/20 Project: Homestead at Clarendon Calc. By: Location: Fort Collins, Colorado Date: 42,675 sf 75% 32,006 sf 26,137 sf 7,897 sf 34,034 sf 79.8% Total Treatment Area Percent Total Project Area Treated 08/05/20 Onsite LID Treatment F. Wegert Vegetated Buffers Total New Impervious Area Project Summary Target Treatment Percentage Minimum Area to be Treated by LID measures LID Treatment Rain Gardens VAULT ELEC E ELEC E VAULT ELEC CONTROL IRR CONTROL IRR CONTROL IRCRONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR X X / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / Project: Calc. By: Date: 2.0% per City of Fort Collins SWCM 5.0% per City of Fort Collins SWCM 10.0% per City of Fort Collins SWCM 2.5% 8.3% 14 ft per City of Fort Collins SWCM 14 ft to 48 ft 25 ft 14 ft to 52 ft 42 ft 15,794 ft2 Entire Residential Area 24,698 ft2 1.56 Min. Allowable Cross-Slope Max. Allowable Cross-Slope for LID Max. Allowable Cross-Slope VEGETATED BUFFER Basin A Design Data & Analysis Vegetated Buffer Area Run-on Ratio Homestead at Clarendon F. Wegert August 5, 2020 Design Width (S <= 10.0%) Average Design Width (S <= 10.0%) Min. Design Cross-Slope (Smin) Max. Design Cross-Slope (Smax) Min. Allowable Width Design Width (S <= 5.0%) Average Design Width (S <= 5.0%) Treatment Area Note: Existing coverage consists of well established native grasses with over 95% coverage. As much existing vegetation and grading will be preserved as feasibly possible. Disturbed areas within vegetated buffer will occur along rear lot lines, and this work is necessary to daylight lot grades into existing topography. Any disturbed areas will be replaced with a native grass seed mixture and landscaping in accordance with the erosion control and landscaping plans. Average slopes are around 2.5% towards the south and east and gradually get steeper towards the north and west. An existing irrigation ditch along the north edge of the grass buffer impacts the slopes along the north edge of the grass buffer. The steeper slopes, greater than 5.0%, are generally along the irrigation ditch. Some minor grading will be required in the grass buffer to daylight proposed lawn grades into existing grades. However, any disturbed areas within the grass buffer will be revegetated per the erosion control ATTACHMENT 3 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 4 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 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 491850 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'' W 40° 31' 11'' N 105° 5' 34'' W 40° 31' 6'' N 105° 5' 46'' W 40° 31' 6'' N 105° 5' 34'' W N 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 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 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 491850 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'' W 40° 31' 11'' N 105° 5' 34'' W 40° 31' 6'' N 105° 5' 46'' W 40° 31' 6'' N 105° 5' 34'' W N 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 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 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 4485310 4485330 4485350 4485370 4485390 4485410 4485430 4485450 4485470 491850 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'' W 40° 31' 11'' N 105° 5' 34'' W 40° 31' 6'' N 105° 5' 46'' W 40° 31' 6'' N 105° 5' 34'' W N 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 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 5 DRAINAGE EXHIBITS USGS The National Map: Orthoimagery. Data refreshed October, 2017. National Flood Hazard Layer FIRMette 0 250 500 1,000 1,500 2,000 Feet Ü 105°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 HAZARD SPECIAL AREAS FLOOD Without Zone A, V, Base A99 Flood Elevation (BFE) With BFE or Depth Zone AE, AO, AH, VE, AR Regulatory Floodway 0.of 2% 1% Annual annual Chance chance Flood flood with Hazard, average Areas depth areasdrainage of less less than than one one foot square or with mile Zone X Future ChanceAnnual Conditions Flood Hazard 1% Zone X Area Levee.to with See Reduced Notes. Flood Risk due Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This digital map flood complies maps if with it is FEMA's not void standards as described for the below. use of The accuracy basemap standards shown complies with FEMA's basemap The authoritative flood hazard NFHL information web services is derived provided directly by FEMA. from This the map was reflectnot exported changes on or 4/amendments 5/2019 at 2:25:subsequent 52 PM and to this does date and time. becomeor The superseded NFHL and effective by new data information over time. may change This elementsmap map image do not is appear: void if basemap the one or imagery, more of flood the following zone labels, legend, FIRM panel scale number, bar, map and creation FIRM effective date, community date. Map identifiers,images for unmapped regulatoryfor purposes. and unmodernized areas cannot be used Legend OTHER FLOOD AREAS HAZARD OF OTHER AREAS STRGUECNTUERREASL FEATURES OTHER MAP PANELS 8 1:6,000 B 20.2 The point pin selected displayed by the on the user map and is does an approximate not represent an authoritative property location. VAULT ELEC E ELEC E VAULT ELEC CONTROL IRR CONTROL IRR CONTROL IRCRONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR X X X X X / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / VAULT ELEC E ELEC E VAULT ELEC CONTROL IRR CONTROL IRR CONTROL IRCRONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR X X X X X / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / CLARENDON HILLS DRIVE LANGDALE DRIVE FRONT RANGE COMMUNITY COLLEGE CLARENDON HILLS FIRST FILING ACCESS EASEMENT LOT 1 LOT 2 LOT 3 LOT 6 LOT 5 LOT 7 LOT 8 LOT 4 TRACT A A 1.56 ac / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / B1 0.16 ac B2 1.21 ac B3 0.09 ac B4 0.09 ac OS1 0.12 ac OS2 0.06 ac PROPOSED RAIN GARDEN WITH FOREBAY PROPOSED DRIVEWAY PROPOSED RAIN GARDEN WITH FOREBAY PROPOSED RETAINING WALL WITH WEIR TO DIVIDE POND FROM RAIN GARDEN (RE: LANDSCAPE ARCHITECT) PROPOSED RETAINING WALL WITH WEIR TO DIVIDE POND FROM RAIN GARDEN (RE: LANDSCAPE ARCHITECT) PROPOSED RETAINING WALL (RE: LANDSCAPE ARCHITECT) PROPOSED VERTICAL CURB & GUTTER PROPOSED POND B A OS1 PROPOSED OUTLET STRUCTURE CONSTRUCTED AS PART OF WALL PROPOSED SIDEWALK CULVERT WITH CONCRETE CHASE PROPOSED OUTLET PIPE TRACT B DITCH ACCESS EASEMENT (WIDTH VARIES - SEE NOTE 2) SMITH LATERAL EXISTING PRIVATELY OWNED IRRIGATION DITCH (SEE NOTE 2) DR2 PROPOSED DRAINAGE EXHIBIT 15 CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R NORTH ( IN FEET ) 1 inch = ft. 30 0 30 Feet 30 60 90 Sheet HOMESTEAD 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 CONSTRUCTION REVIEW SET E NGINEER ING N O R T H E RN FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.com of 15 LEGEND: DESIGN POINT A FLOW ARROW DRAINAGE BASIN LABEL NOTES: 1. REFER TO THE PRELIMINARY DRAINAGE LETTER FOR HOMESTEAD AT CLARENDON HILLS FOR ADDITIONAL INFORMATION. 2. THE SMITH LATERAL IS OWNED BY NUMEROUS INDIVIDUAL OWNERS AS WELL AS THE CITY OF FORT COLLINS (THROUGH THE PARKS DEPARTMENT) WHO USE THE DITCH TO CONVEY IRRIGATION WATER. APPROVAL FROM THE IRRIGATION DITCH OWNERS IS REQUIRED PRIOR TO ANY WORK ON THE DITCH OR IN ITS EASEMENT, AS WELL AS BEFORE ANY STORMWATER CAN BE DISCHARGED, OR PLANNED 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. BENCHMARK FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION C PROJECT DATUM: NAVD88 CITY OF FORT COLLINS BENCHMARK 5-02 1/2 MILE SOUTH OF HARMONY ROAD, APPROXIMATELY 200 FEET NORTH OF WOODED CREEK COURT, ON THE WEST SIDE OF SHIELDS STREET, ON THE NORTHWEST CORNER OF A STORM INLET. ELEV. = 5089.11 CITY OF FORT COLLINS BENCHMARK 8-13 SOUTHEAST CORNER OF HARMONY RD. AND SHIELDS ON THE NORTHEAST CORNER OF A CONCRETE TRAFFIC SIGNAL BASE. ELEV. = 5086.71 PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTS HAVE 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 BEARINGS THE BASIS OF BEARINGS IS THE WEST LINE OF SECTION 2-6-69 AS BEARING NORTH 00° 17' 10" EAST (ASSUMED BEARING). PROPOSED CONTOUR EXISTING CONTOUR PROPERTY BOUNDARY PROPOSED STORM DRAIN / IRRIGATION EXISTING CURB AND GUTTER PROPOSED SWALE PROPOSED LOT LINE EASEMENT Drainage Summary Table (Proposed Basins) Design Point Basin ID Total Area (acres) C2 C100 2-Yr Tc (min) 100-Yr Tc (min) Q2 (cfs) Q100 (cfs) 52848.0235 52848.02 1.556 0.31 0.39 6485.02 6485.02 18952.13 1.11 b 3897.174 0.163 0.49 0.62 5.00 5.00 288.94 1.00 b 3034.14 1.213 0.56 0.70 9.93 9.93 1.53 6.68 b 5312.809 0.089 0.53 0.66 5.00 5.00 90.99 0.59 os1 OS1 0.122 0.40 0.49 10.89 10.89 0.10 0.46 os2 OS2 0.064 0.25 0.31 5.00 5.00 0.05 0.20 #REF! #REF! #REF! #REF! #REF! #REF! #REF! #REF! #REF! Detention Pond and Rain Garden Summary Description Required Volume (cu. ft.) Design Volume (cu. ft.) Release Rate (cfs) Crest of Pond Elev. Water Surface Elev. Freeboard (ft) Detention Pond 8,972 9,536 0.24 5090.6 5089.52 1.08 East Rain Garden 327 333 n/a 5090.6 5090.52 0.08 West Rain Garden 327 329 n/a 5090.6 5090.52 0.08 Drainage Summary Table (Existing Basins) Design Point Basin ID Total Area (acres) C2 C100 2-Yr Tc (min) 100-Yr Tc (min) Q2 (cfs) Q100 (cfs) ex a EX A 2.382 0.25 0.31 14.06 14.06 1.14 5.00 ex b EX B 0.684 0.25 0.31 7.41 7.41 0.43 1.88 ex os1 EX OS1 0.147 0.25 0.31 11.08 11.08 0.08 0.34 ex os2 EX OS2 0.064 0.25 0.31 5.42 5.42 0.05 0.20 PROPOSED DRAINAGE BASIN BOUNDARY 50' WETLANDS BUFFER / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / CLARENDON HILLS DRIVE LANGDALE DRIVE FRONT RANGE COMMUNITY COLLEGE CLARENDON HILLS FIRST FILING EX B 0.68 ac EX A 2.38 ac EX OS1 0.15 ac EX OS2 0.06 ac SMITH LATERAL EXISTING PRIVATELY OWNED IRRIGATION DITCH (SEE NOTE 2) DR1 HISTORIC DRAINAGE EXHIBIT 14 CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R NORTH ( IN FEET ) 1 inch = ft. 30 0 30 Feet 30 60 90 Sheet HOMESTEAD 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 CONSTRUCTION REVIEW SET E NGINEER ING N O R T H E RN FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.com of 15 LEGEND: DESIGN POINT A FLOW ARROW DRAINAGE BASIN LABEL EXISTING DRAINAGE BASIN BOUNDARY FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION C PROPOSED CONTOUR EXISTING CONTOUR PROPERTY BOUNDARY PROPOSED STORM DRAIN / IRRIGATION EXISTING CURB AND GUTTER PROPOSED SWALE PROPOSED LOT LINE EASEMENT Drainage Summary Table (Existing Basins) Design Point Basin ID Total Area (acres) C2 C100 2-Yr Tc (min) 100-Yr Tc (min) Q2 (cfs) Q100 (cfs) ex a EX A 2.382 0.25 0.31 14.06 14.06 1.14 5.00 ex b EX B 0.684 0.25 0.31 7.41 7.41 0.43 1.88 ex os1 EX OS1 0.147 0.25 0.31 11.08 11.08 0.08 0.34 ex os2 EX OS2 0.064 0.25 0.31 5.42 5.42 0.05 0.20 NOTES: 1. REFER TO THE PRELIMINARY DRAINAGE LETTER FOR HOMESTEAD AT CLARENDON HILLS FOR ADDITIONAL INFORMATION. 2. THE SMITH LATERAL IS OWNED BY NUMEROUS INDIVIDUAL OWNERS AS WELL AS THE CITY OF FORT COLLINS (THROUGH THE PARKS DEPARTMENT) WHO USE THE DITCH TO CONVEY IRRIGATION WATER. APPROVAL FROM THE IRRIGATION DITCH OWNERS IS REQUIRED PRIOR TO ANY WORK ON THE DITCH OR IN ITS EASEMENT, AS WELL AS BEFORE ANY STORMWATER CAN BE DISCHARGED, OR PLANNED 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. BENCHMARK PROJECT DATUM: NAVD88 CITY OF FORT COLLINS BENCHMARK 5-02 1/2 MILE SOUTH OF HARMONY ROAD, APPROXIMATELY 200 FEET NORTH OF WOODED CREEK COURT, ON THE WEST SIDE OF SHIELDS STREET, ON THE NORTHWEST CORNER OF A STORM INLET. ELEV. = 5089.11 CITY OF FORT COLLINS BENCHMARK 8-13 SOUTHEAST CORNER OF HARMONY RD. AND SHIELDS ON THE NORTHEAST CORNER OF A CONCRETE TRAFFIC SIGNAL BASE. ELEV. = 5086.71 PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTS HAVE 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 BEARINGS THE BASIS OF BEARINGS IS THE WEST LINE OF SECTION 2-6-69 AS BEARING NORTH 00° 17' 10" EAST (ASSUMED BEARING). 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 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 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 / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / CLARENDON HILLS DRIVE LANGDALE DRIVE VEGETATED BUFFER RAIN GARDEN RAIN GARDEN HOMESTEAD AT CLARENDON HILLS SHEET NO: P:\1013-008\DWG\DRNG\1013-008_LID.DWG 301 N. Howes Street, Suite 100 Fort Collins, Colorado 80521 E NGINEER ING N O R T H E RN PHONE: 970.221.4158 www.northernengineering.com DRAWING REFERENCE: LID TREATMENT EXHIBIT F. Wegert 1 in = 60 ft August 5, 2020 LID-1 DRAWN BY: SCALE: ISSUED: ( IN FEET ) 0 1 INCH = 60 FEET 60 60 LEGEND RAIN GARDEN TREATMENT AREA VEGETATED BUFFER VEGETATED BUFFER TREATMENT AREA UNTREATED AREA NOTES: 1. EXCEPT FOR LOTS 1 AND 8, UNTREATED AREA CONSISTS OF LANDSCAPING AND LAWNS. 2. RAIN GARDEN TREATMENT AREA CONSISTS OF APPROXIMATELY SOUTH 2 3 OF LOT, ROOFS, DRIVEWAYS, AND SHARED DRIVEWAY FOR LOTS 2 - 7. 3. APPROXIMATELY NORTH 1 3 OF LOTS WILL DRAIN TOWARDS VEGETATED BUFFER AREA BETWEEN REAR LOT LINES AND IRRIGATION DITCH. Block 23 / Morningstar LID Summary Project Summary Total New Impervious Area 42,675 sf Target Treatment Percentage 75% Minimum Area to be Treated by LID measures 32,006 sf Rain Gardens Total Rain Garden Treatment Area 26,137 sf Vegetated Buffers Total Vegetated Buffer Treatment Area 7,897 sf Total Treatment Area 34,034 sf Percent Total Project Area Treated 79.8% 1013-008 Homestead at Clarendon Project Number : Project Name : Detention Pond Page 1 of 1 1013-008_Pond_FAA_Fort Collins.xls os2 OS2 0.25 0.25 0.31 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 5.00 5.00 5.00 a North 0.31 0.31 0.39 60 92.89 89.01 6.47% 6.1 6.1 5.5 N/A N/A N/A 705 89.01 85.49 0.50% 0.11 110.86 14.25 14.25 116.38 b South 0.54 0.54 0.67 95 94.23 92.41 1.92% 8.3 8.3 6.3 350 92.41 84.93 2.14 2.92 2.00 N/A N/A N/A 10.27 10.27 8.30 Overland Flow, Time of Concentration: DEVELOPED TIME OF CONCENTRATION COMPUTATIONS Channelized Flow Swale Flow Design Point Basin(s) Tt = L / 60V (Equation 6-4 per MHFD) Tc = Ti + Tt (Equation 6-2 per MHFD) Overland Flow Time of Concentration Homestead at Clarendon F. Wegert August 5, 2020 Gutter/Swale Flow, Time of Concentration: Combined and Routed Basins Intensity, i (per Table 3.4-1 of the Fort Collins Stormwater Manual) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ Rational Equation: Q = CiA (Equation 6-1 per MHFD) (Equation 6-4 per MHFD) (Equation 3.3-2 per Fort Collins Stormwater Manual) } 𝑇𝑖 = 1.87 1.1 − 𝐶 ∗ 𝐶𝑓 𝐿 𝑆 ൗ 1 3 Page 2 of 3 Lawns, Clayey Soil > 7%: C = 0.35, Percent Impervious = 2% Combined and Routed Basins 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Avg Slope 2-7% Open Space (undeveloped): C = 0.25, Percent Impervious = 2% USDA SOIL TYPE: B Page 1 of 3 Combined and Routed Basins Intensity, i (per Table 3.4-1 of the Fort Collins Stormwater Manual) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ Rational Equation: Q = CiA (Equation 6-1 per MHFD) Overland Flow, Time of Concentration: HISTORIC TIME OF CONCENTRATION COMPUTATIONS Channelized Flow Swale Flow Design Point Basin(s) Tt = L / 60V (Equation 6-4 per MHFD) Tc = Ti + Tt (Equation 6-2 per MHFD) Overland Flow Time of Concentration Homestead at Clarendon F. Wegert August 5, 2020 (Equation 6-4 per MHFD) (Equation 3.3-2 per Fort Collins Stormwater Manual) } 𝑇𝑖 = 1.87 1.1 − 𝐶 ∗ 𝐶𝑓 𝐿 𝑆 ൗ 1 3 Page 2 of 3 August 5, 2020 Project: Calculations By: Date: 2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins Stormwater Manual (FCSM). Lawns, Clayey Soil, Avg Slope 2-7% Note: 1) A C2 of 0.25 was assumed per the Clarendon Hills 4th Filing Drainage Report as the historic condition. Page 1 of 3