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Home My WebLink AboutANGIE LEE PERIODONTICS - PDP - PDP160012 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1501 Academy Ct. Ste. 203 Fort Collins, Colorado 80524 (970) 530-4044 Preliminary Drainage Summary Angie Lee Periodontics Fort Collins, CO Prepared for: Aspen Summit, LLC 1223 Red Oak Court Fort Collins, CO 80525 March 30, 2016 Drainage Addendum Angie Lee Periodontics Fort Collins, CO 1 U15013-DrainageSummary-Preliminary.doc March 30, 2016 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Angie Lee Periodontics Fort Collins, Colorado Project Number: U15013 Dear Staff: United Civil Design Group, LLC. is pleased to submit this Preliminary Drainage Addendum for the Angie Lee Periodontics site in Fort Collins, Colorado. In general, this summary serves to document the stormwater impacts associated with the proposed project and to verify that the project does conform to the intent and requirements set forth in the approved final drainage report entitled, “Miramont Self Storage”, prepared by John H. King III Development Consultant and dated November 1, 1997. Site Location and Project Description The Angie Lee Periodontics development site (referred herein as ”the site”) is located at 4803 East Boardwalk Drive in the northeast quarter of Section 1, Township 6 North, Range 69 West of the Sixth P.M., City of Fort Collins, Larimer County, Colorado. The site consists of approximately 0.53 acres and is bounded by Boardwalk Drive on the east, a private drive to the north, and existing commercial properties to the south and west. See the attached Drainage Plan for additional information. The planned development for the site will consist of the following: • The construction of single-story, office building with a proposed full-buildout footprint of approximately 6,550 sf (including approximately 2,800 sf of future office). • The construction of private drive lane, parking area and sidewalks in support of the building construction. • The construction of utilities to support the proposed building including sanitary, water and storm drainage. Drainage Addendum Angie Lee Periodontics Fort Collins, CO 2 U15013-DrainageSummary-Preliminary.doc Existing Conditions Hydrology The site, which is located within the McClellands Basin, is approximately 0.53 acres in size and is currently undeveloped with an existing percent-imperviousness of approximately 2%. Storm runoff from the site currently drains towards the southeast corner of the site where it exits the site and is intercepted by an existing 18” culvert which conveys the runoff to the existing Miramont Self-Storage detention and waterquality pond. Floodplain The site is not located within a FEMA or City-regulatory floodway or floodplain. Detention The regional detention pond constructed for the Miramont Self Storage development and located south of the site provides both detention and water quality for the site and is not being modified with this project. Developed Conditions In part, the intent of this Drainage Addendum is to verify that the Angie Lee Periodontics project conforms to the intent and requirements set forth in the previous drainage report for this site. As such, the following sections of this Addendum compare the proposed design to that shown in the aforementioned report. Hydrology Basins A and B as shown in the attached Drainage Plan contains the majority of the site which will be collected via curb and gutter, swales and storm sewer and routed to the south property line and ultimately to the regional pond built with the Miramont Self Storage project south of the site, matching the drainage patterns set forth in the Miramont Self Storage report. Basin OS1 contains a small area north and east of the proposed building that will drain either directly to the private drive north of the site or to Boardwalk Avenue to the east. This area was originally designed to be collected via a swale and conveyed to the south property line. However, with the construction within this basin of the pond outlet and sidewalk chase for the development to the north, the previously planned swale would be intercepted by the sidewalk chase and conveyed to Boardwalk Avenue. Therefore, the area has been designed to drain directly to the adjacent roadways. This basin contains a small area (2,665 sf) and will contribute a small flowrate (0.2 cfs) to Boardwalk Avenue in the 100-year event. The additional flow to Boardwalk Avenue is not anticipated to negatively impact the street capacity of Boardwalk Avenue as the Drainage Addendum Angie Lee Periodontics Fort Collins, CO 3 U15013-DrainageSummary-Preliminary.doc existing roadway has a grade of approximately 3.6% adjacent to the site and an approximate 100-year capacity of 150 cfs. Basins OS2 and OS3 contain small areas west and south of the paving on the site that are collected via a shared swale along the west and south property lines and conveyed to the existing storm sewer south of the site, and ultimately to the Miramont regional pond to the south. This matches the drainage patterns set forth in the Miramont Self Storage report. The following table compares the characteristics of proposed onsite basins (basins A1- A3, B1 and OS1- OS2) to the same area as shown in the drainage report for Miramont Self Storage: Comparison Summary Table Proposed Onsite Basins Miramont Report Overall Area (acres) 0.53 0.53 Composite C Value 0.92 0.94 Imperviousness Area (sf) 16,000 13,500 Area Draining to Boardwalk (sf) 2,665 0.00 Area Draining to Miramont Regional Pond (acres) 0.47 0.53 As shown in the above table, the proposed improvements for the development result in a lower composite C value for the site than that shown in the Miramont report. However, the site is proposing additional impervious area for the ultimate site. This additional area is anticipated to have a negligible impact to the regional pond or downstream properties and/or right-of-way. This is due to the fact that, with accounting for the area draining directly to Boardwalk Avenue, there is less overall area draining to the regional pond. In addition, the regional pond was designed (per the Miramont report) with a volume in excess of the required 100-year volume by approximately 3,800 cf. The additional volume required in the pond due to increased impervious area is less than 600 cf. Therefore, in general, the site does meet the requirements set forth in the Miramont Self Storage drainage report and the minor alterations being made to the site from those previously assumed are not anticipated to negatively impact the previously constructed drainage improvements. Storm Sewer The proposed improvements do not require any public storm sewer. The site will only require small storm sewer and roof drains to collect and convey the flows from the building roof and bioretention pond to the south property line. Drainage Addendum Angie Lee Periodontics Fort Collins, CO 4 U15013-DrainageSummary-Preliminary.doc Detention and Water Quality Requirements Both detention and water quality are provided for the site in the pond constructed with the Miramont Self Storage development. No additional detention or water quality is required; however, the City encourages additional water quality onsite. The development is proposing to provide additional water quality measures in the form of a bioretention pond to meet the Low Impact Development requirements discussed in the next section. Low Impact Development (LID) Requirements In December of 2015, City Council adopted the revised LID policy and criteria. The proposed development is required to meet the newly adopted criteria. Per the criteria, the site must: • Treat no less than 75% of any newly added impervious area using one or a combination of LID techniques. • Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques when at least 25% of any newly added pavement is provided with permeable pavement. The following measures are being implemented with this proposed development: Bioretention Pond Basins A1-A3 (with 12,266 sf of impervious area) will be routed through a bioretention pond located south of the proposed building. The bioretention pond will have a maximum depth of 9-inches with an overall volume of 415 cubic feet which exceeds the minimum design requirements for the area. Refer to the Appendix for additional calculations. Permeable Pavers As the development intends to treat more than 75% of the proposed impervious area with the Bioretention pond, no permeable pavers are being proposed with this project. In total, the development is proposing to collect and treat 12,266 sf (77%) of the overall 15,947 sf of impervious area developed with this project. In addition, the site is also being designed with other various open landscaped areas and vegetated swales to provide additional water quality in addition to the areas being treated with bioretention. Four Step Process With the adoption of the USDCM, the City has also adopted the “Four Step Process” that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this summary describe each step and how it has been utilized for this project: Drainage Addendum Angie Lee Periodontics Fort Collins, CO 5 U15013-DrainageSummary-Preliminary.doc Step 1 – Employ Runoff Reduction Practices The objective of this step is to reduce runoff peaks and volumes and to employ the technique of “minimizing directly connected impervious areas” (MDCIA). This project accomplishes this by: • Routing the roof and pavement flows through a biroretention pond and through vegetated swales to increase time of concentration, promote infiltration and provide water quality. Step 2 – Provide Water Quality Capture Volume (WQCV) The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV is provided within a regional waterquality pond, so no additional WQCV is required. However, the development is providing a small bioretention pond to meet the LID requirements, and therefore, additional WQCV. Step 3 – Stabilize Drainageways The site is not adjacent or near a major drainageway; however, this project will pay stormwater development and stormwater utility fees which the City uses, in part, to maintain the stability of the City drainageway systems. Step 4 – Consider Need for Industrial and Commercial BMPs This step is generally considered for industrial and commercial sites. As this development is proposing a small office building, no specialized BMPs have been considered for this project. Standard Operating Procedures (SOPs) In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled activities, as well as non-routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures should clearly identify BMP maintenance responsibility. BMP maintenance is typically the responsibility of the entity owning the BMP. Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs including vegetative swales and bioretention pond are to be maintained by the property owner, homeowner’s association (HOA), or property manager. Drainage Addendum Angie Lee Periodontics Fort Collins, CO 6 U15013-DrainageSummary-Preliminary.doc Erosion Control Erosion control, both temporary and permanent, is a vital part of any development project. For this project, the site disturbance will be over 10,000 sf; therefore, a comprehensive Erosion Control Report will be completed during the FCP phase of the project. Conclusions In conclusion, the drainage system proposed within this Drainage Summary provides adequate conveyance of the developed stormwater runoff from the proposed development to existing discharge locations and drainage systems. It should also be noted that with this summary and the corresponding design, every attempt has been made to minimize any negative impacts on the downstream receiving waters. With the incorporation of the LID techniques, the site will discharge a lower sediment load and less runoff. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This addendum was prepared in compliance with technical criteria set forth in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the FCSCM. If you should have any questions or comments as you review this drainage summary, please feel free to contact us at your convenience. Sincerely, United Civil Design Group, LLC Kevin Brazelton, PE Engineering Manager APPENDICES APPENDIX A - Hydrology Calculations APPENDIX B - LID Calculations APPENDIX C - Hydraulic Calculations (Reserved for Final Submittal) APPENDIX D – Referenced Material APPENDIX E - Drainage Plan APPENDIX A Hydrology Calculations Runoff Summary Angie Lee Periodontics Fort Collins Area Q2 Q 100 (acre) (cfs) (cfs) A1 A1 0.05 13% 0.336 0.420 0.04 0.19 A2 A2 0.21 92% 0.907 1.000 0.53 2.04 A3 A3 0.08 90% 0.950 1.000 0.23 0.83 B1 B1 0.08 90% 0.950 1.000 0.21 0.78 OS1 OS1 0.06 10% 0.315 0.394 0.05 0.20 OS2 OS2 0.06 2% 0.250 0.313 0.03 0.15 OS3 OS3 0.07 54% 0.665 0.831 0.14 0.60 Proposed Basins C C100 Basin Design Point %I 2 P:\U15013 - 4803 Boardwalk Office\Reports\Drainage\Calculations\U15013_Hydrology_Standard.xlsm Calculations by: KRB Date: 3/22/2016 Angie Lee Periodontics Runoff Coefficients and % Impervious Fort Collins Roof (1) Asphalt Walks(1) Gravel(1) Lawns(1) %I = 90% %I = 100% %I = 90% %I =40% %I=2% acres sf sf sf sf sf sf C2 C100 A1 A1 0.05 2007 247 1760 12.8% C/D 0.34 0.42 A2 A2 0.21 8936 6279 2104 553 91.6% C/D 0.91 1.00 A3 A3 0.08 3636 3636 0 90.0% C/D 0.95 1.00 B1 B1 0.08 3433 3433 0 90.0% C/D 0.95 1.00 OS1 OS1 0.06 2663 248 2415 10.2% C/D 0.32 0.39 OS2 OS2 0.06 2412 2412 2.0% C/D 0.25 0.31 OS3 OS3 0.07 3157 1870 1287 54.1% C/D 0.66 0.83 - - - - - - - - - Basin A Total 0.3 14579 3636 6279 2351 0 2313 80% 0.84 1.00 Onsite Total(3) 0.5 23087 7069 6279 2599 0 7140 66% 0.73 0.92 Notes: (1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious. (2) Runoff C is based on composite C value (City equation RO-8), and City correction factors in Table RO-12. (4) Excludes Basin OS3. Proposed Basins Basin Areas Composite Imperviousness (%I) Design Pt. Total Total Composite Runoff NRCS Soil Coefficients (2) Type P:\U15013 - 4803 Boardwalk Office\Reports\Drainage\Calculations\U15013_Hydrology_Standard.xlsm Calculations by: KRB Date: 3/22/2016 Angie Lee Periodontics Time of Concentration Fort Collins Area Length Slope ti (2) Length Slope Velocity (3) tt (4) Check tc? Total Length tc (5) acres ft % min ft % fps min min Urban? ft min min A1 A1 0.0 Lawn 0.09 26 11.5 4.1 55 1.55 7 0.9 1.1 5.2 Yes 81 10 5 A2 A2 0.2 Paved 0.90 39 3 1.6 100 3.8 20 3.9 0.4 2.0 Yes 139 11 5 A3 A3 0.1 Roof 0.73 20 5 1.8 65 2 20 2.8 0.4 2.1 Yes 85 10 5 B1 B1 0.1 Roof 0.73 20 5 1.8 65 2 20 2.8 0.4 2.1 Yes 85 10 5 OS1 OS1 0.1 Lawn 0.09 50 4 8.1 20 2 7 1.0 0.3 8.5 Yes 70 10 8 OS2 OS2 0.1 Lawn 0.09 19 18 3.1 265 1.4 7 0.8 5.3 8.4 Yes 284 12 8 OS3 OS3 0.1 Roof 0.73 20 5 1.8 162 1.25 7 0.8 3.4 5.2 Yes 182 11 5 - - - - - - - - - - - - - - - - - - - - - - - - Notes: (1) C5 based initial ground type and Table RO-5 (4) tt=L/(V*60 sec/min) (2) ti = [1.87(1.1-CxCf)L1/2]/S1/3, S= slope in %, L=length of overland flow (400' max) (5) tc check (for urban or developed areas only) = total length/180 + 10 (3) V=CvS 0.5 , S=watercourse slope in ft/ft, UDFCD Equation RO-4 (6) min tc = 5 min Proposed Basins Initial Ground Type C(1) Cv ti+tt Final tc (6) tc Check for Urbanized Basin Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt) Design Pt. P:\U15013 - 4803 Boardwalk Office\Reports\Drainage\Calculations\U15013_Hydrology_Standard.xlsm Calculations by: KRB Date: 3/22/2016 Rational Method Peak Runoff Angie Lee Periodontics Fort Collins Final tc (6) I2 I100 Q2 Q100 acre min in/hr in/hr cfs cfs A1 A1 0.05 5 0.336 0.420 2.85 9.95 0.04 0.19 A2 A2 0.21 5 0.907 1.000 2.85 9.95 0.53 2.04 A3 A3 0.08 5 0.950 1.000 2.85 9.95 0.23 0.83 B1 B1 0.08 5 0.950 1.000 2.85 9.95 0.21 0.78 OS1 OS1 0.06 8 0.315 0.394 2.40 8.38 0.05 0.20 OS2 OS2 0.06 8 0.250 0.313 2.40 8.38 0.03 0.15 OS3 OS3 0.07 5 0.665 0.831 2.85 9.95 0.14 0.60 - - - - - - - - - - - - - - - - - - - - - Totals 1.23 4.79 Peak Discharge Proposed Basins Design Pt. Area Basin C100 Runoff Coefficients Rainfall Intensity C2 P:\U15013 - 4803 Boardwalk Office\Reports\Drainage\Calculations\U15013_Hydrology_Standard.xlsm Calculations by: KRB Date: 3/22/2016 APPENDIX B LID Calculations Angie Lee Periodontics Fort Collins, Colorado Low Impact Development Summary Proposed Impervious Area (sf) Individual Basins Basin A1 247 Bioretention Pond 247 2% Basin A2 8,383 Bioretention Pond 8,383 53% Basin A3 3,636 Bioretention Pond 3,636 23% Basin B1 3,433 None 0 0% Basin OS1 248 None 0 0% Basin OS2 0 None 0 0% Total Site 15,947 12,266 77% Low Impact Development (LID) Treatment Areas Basin LID Treatment Area Treated (sf) % of Site Treated Calculations by: KRB Date: 3/22/2016 P:\U15013 - 4803 Boardwalk Office\Reports\Drainage\Calculations\U15013_Hydrology_Standard.xlsm Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 80.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.800 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.26 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 14,579 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 319 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCVOTHER = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCVUSER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 9 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 213 sq ft D) Actual Flat Surface Area AActual = 250 sq ft E) Area at Design Depth (Top Surface Area) ATop = 700 sq ft F) Rain Garden Total Volume VT= 356 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = N/A ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Design Procedure Form: Rain Garden (RG) KRB United Civil Design Group March 22, 2016 Angie Lee Periodontics Fort Collins Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.03.xlsm, RG 3/22/2016, 3:42 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? PROVIDE A 30 MIL (MIN) PVC LINER WITH CDOT CLASS B GEOTEXTILE ABOVE IT. USE THE SAME GEOTEXTILE BELOW THE LINER IF THE SUBGRADE IS ANGULAR 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) KRB United Civil Design Group March 22, 2016 Angie Lee Periodontics Fort Collins Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.03.xlsm, RG 3/22/2016, 3:42 PM STAGE STORAGE TABLE ELEV AREA (sq. ft.) DEPT H (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) CONIC INC. VOL. (cu. ft.) CONIC TOTAL VOL. (cu. ft.) 4,996.700 5.38 N/A N/A 0.00 N/A 0.00 4,996.800 111.95 0.100 5.87 5.87 4.73 4.73 4,996.900 255.06 0.100 18.35 24.22 17.87 22.60 4,997.000 381.05 0.100 31.81 56.02 31.60 54.19 4,997.100 451.59 0.100 41.63 97.65 41.58 95.77 4,997.200 522.55 0.100 48.71 146.36 48.66 144.44 4,997.300 605.81 0.100 56.42 202.78 56.37 200.80 4,997.400 698.08 0.100 65.19 267.97 65.14 265.94 4,997.500 6,180.35 0.100 343.92 611.90 298.52 564.46 4,997.600 7,046.44 0.100 661.34 1273.24 660.87 1225.33 VOLUME = 415 CF AT 4997.45 (319 CF REQUIRED) APPENDIX C Hydraulic Calculations (Reserved for Final Submittal) APPENDIX D Referenced Material 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 Angie Lee Periodontics Natural Resources Conservation Service March 22, 2016 8 Custom Soil Resource Report Soil Map 4485370 4485400 4485430 4485460 4485490 4485520 4485550 4485580 4485610 4485370 4485400 4485430 4485460 4485490 4485520 4485550 4485580 4485610 494350 494380 494410 494440 494470 494500 494530 494350 494380 494410 494440 494470 494500 494530 40° 31' 16'' N 105° 4' 0'' W 40° 31' 16'' N 105° 3' 52'' W 40° 31' 8'' N 105° 4' 0'' W 40° 31' 8'' N 105° 3' 52'' 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: 1:1,220 if printed on A portrait (8.5" x 11") sheet. Larimer County Area, Colorado 36—Fort Collins loam, 3 to 5 percent slopes Map Unit Setting National map unit symbol: jpw9 Elevation: 4,800 to 5,500 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: Prime farmland if irrigated Map Unit Composition Fort collins and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins Setting Landform: Terraces, fans Landform position (three-dimensional): Base slope, riser Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 20 inches: loam, clay loam H2 - 9 to 20 inches: loam, silt loam, fine sandy loam H3 - 20 to 60 inches: H3 - 20 to 60 inches: H3 - 20 to 60 inches: Properties and qualities Slope: 3 to 5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low 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 very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 25.5 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: Loamy Plains (R067XY002CO) Custom Soil Resource Report 12 Minor Components Ascalon Percent of map unit: 5 percent Kim Percent of map unit: 3 percent Stoneham Percent of map unit: 2 percent 73—Nunn clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2tlng Elevation: 4,100 to 5,700 feet Mean annual precipitation: 14 to 15 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 152 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 derived from igneous, metamorphic and sedimentary rock and/or eolian deposits Typical profile Ap - 0 to 6 inches: clay loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bk1 - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam Properties and qualities Slope: 0 to 1 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) Custom Soil Resource Report 13 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 (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: Clayey Plains (R067BY042CO) 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) Wages 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) 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: jpxn 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: 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, fans Custom Soil Resource Report 14 Landform position (three-dimensional): Base slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 10 inches: clay loam H2 - 10 to 60 inches: clay loam, clay H2 - 10 to 60 inches: Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High 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: 15 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 18.9 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Minor Components Ulm Percent of map unit: 10 percent Satanta Percent of map unit: 5 percent Custom Soil Resource Report 15 This unofficial copy was downloaded on Jul-29-2015 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 Jul-29-2015 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 APPENDIX E Drainage Plan EXISTING BUILDING EXISTING BUILDING EAST BOARDWALK DRIVE OAKRIDGE DRIVE RD OAKRIDGE DRIVE PROPERTY BOUNDARY (TYP.) BIORETENTION POND 20' DRAINAGE A2 EASEMENT 0.03 0.03 A1 0.03 B1 0.03 OS3 OS1 0.03 A3 0.03 OS2 0.03 FUTURE BUILDING PROPOSED BUILDING FFE=5001.50 EXISTING 12" RCP STORM SEWER PROPOSED ROOF DRAIN PROPOSED POND OUTLET STRUCTURE 6" UNDERDRAIN EXISTING DOWNSPOUT (TYP.) BIORETENTION SAND MEDIA ASPEN SUMMIT LLC 03/30/16 U15103 1" = 10' VERTICAL: 1" = N/A HORIZONTAL: ANGIE LEE PERIODONTICS NORTH 3/24/2016 2:38:35 PM C:\UNITED CIVIL\DROPBOX\PROJECTS\U15013 - 4803 BOARDWALK OFFICE\CADD\CP\C5.00_DRAINAGE PLAN.DWG C5.00_DRAINAGE PLAN KRB SDR C500 7 DRAINAGE PLAN 0 10' 20' SCALE: 1" = 10' 5' CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: APPROVED: LEGEND NOTES 1. EXISTING UNDERGROUND AND OVERHEAD PUBLIC AND PRIVATE UTILITIES AS SHOWN ARE INDICATED ACCORDING TO THE BEST INFORMATION AVAILABLE TO THE ENGINEER. 2. VEGETATIVE SWALES AND THE WATERQUALITY POND SHALL BE MAINTAINED BY THE PROPERTY OWNER AND FOLLOW APPLICABLE STANDARD OPERATING PROCEDURES AS SHOWN IN DEVELOPMENT AGREEMENT. LIMITS OF DISTURBANCE EXISTING CURB & GUTTER EXISTING CONCRETE EXISTING BUILDING EXISTING PROPERTY LINE EXISTING LOT LINE EXISTING FENCE EXISTING GRAVEL EXISTING PAVEMENT STRIPING EXISTING WATER EXISTING SANITARY EXISTING OVERHEAD ELECTRIC EXISTING CABLE TV EXISTING ELECTRIC EXISTING STORM SEWER EXISTING GAS BASIN DESIGNATION BASIN AREA (ACRE) 2 - YR RUNOFF COEFF. 100 - YR RUNOFF COEFF. BASIN BOUNDARY DESIGN POINT FLOW DIRECTION EXISTING CONTOUR PROPOSED CONTOUR DRAINAGE SUMMARY PREPARED FOR: JOB NUMBER SHEET NUMBER OF SHEETS DATE SUBMITTED: The engineer preparing these plans will not be responsible for, or liable for, unauthorized changes to or uses of these plans. All changes to the plans must be in writing and must be approved by the preparer of these plans. NO. BY DATE CAUTION REVISIONS: VERTICAL: HORIZONTAL: SCALE PRELIMINARY PLANS NOT FOR CONSTRUCTION 1501 Academy Ct. Ste. 203 Fort Collins, CO 80524 (970) 530-4044 www.unitedcivil.com Civil Engineering & Consulting UNITED CIVIL Design Group PROJ. MGR: DRAWING NAME: PATH: DATE: TIME: DESIGNER: Basin Design Point Area %I C2 C100 Q2 Q100 (acre) (cfs) (cfs) Proposed Basins A1 A1 0.05 13% 0.336 0.420 0.04 0.19 A2 A2 0.21 92% 0.907 1.000 0.53 2.04 A3 A3 0.08 90% 0.950 1.000 0.23 0.83 B1 B1 0.08 90% 0.950 1.000 0.21 0.78 OS1 OS1 0.06 10% 0.315 0.394 0.05 0.20 OS2 OS2 0.06 2% 0.250 0.313 0.03 0.15 OS3 OS3 0.07 54% 0.665 0.831 0.14 0.60