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HomeMy WebLinkAboutCROWNE AT SUNIGA - PDP230007 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT PRELIMINARY DRAINAGE REPORT THE CROWNE AT SUNIGA FORT COLLINS, COLORADO MARCH 15, 2023 NORTHERNENGINEERING.COM 970.221.4158 FORT COLLINS GREELEY This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is necessary, we recommend double-sided printing. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY COVER LETTER March 15, 2023 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80526 RE: PRELIMINARY DRAINAGE REPORT FOR THE CROWNE AT SUNIGA (1893-001) Dear Staff: Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This report accompanies the Preliminary Development Review submittal for the Crowne at Suniga. This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual (FCSCM) and serves to document the stormwater impacts associated with the proposed the Crowne at Suniga multi-family project. We understand review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the FCSCM. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. SCHYLER KING, EIT BLAINE MATHISEN, PE Project Engineer Project Engineer NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY TABLE OF CONTENTS TABLE OF CONTENTS GENERAL LOCATION AND DESCRIPTION .......................................................... 1 DRAIN BASINS AND SUB-BASINS ..................................................................... 3 DRAINAGE DESIGN CRITERIA .......................................................................... 4 DRAINAGE FACILITY DESIGN ........................................................................... 7 CONCLUSIONS .............................................................................................. 9 REFERENCES ................................................................................................ 9 TABLES AND FIGURES FIGURE 1 - VICINITY MAP ..................................................................................................1 FIGURE 2 - AERIAL PHOTO ................................................................................................2 FIGURE 3 - FIRMETTE MAP 08069C0981G ........................................................................3 TABLE 1 - MAXIMUM RELEASE RATE CALCULATED BY AREA. ..........................................8 TABLE 2 - SUMMARY OF NEW IMPERVIOUS AREAS BEING TREATED BY LID ...................8 APPENDICES APPENDIX A – HYDROLOGIC COMPUTATIONS APPENDIX B – HYDRAULIC CALCULATIONS – FOR FUTURE USE APPENDIX C –WATER QUALITY/LID COMPUTATIONS APPENDIX D – EROSION CONTROL REPORT APPENDIX E – EXCERPTS FROM PREVIOUS REPORTS AND USDA SOILS REPORT MAP POCKET DR1 – EXISTING DRAINAGE EXHIBIT DR2 – DRAINAGE EXHIBIT NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 1 | 11 GENERAL LOCATION AND DESCRIPTION A. LOCATION Vicinity Map The Crowne at Suniga project site is located in the southwest quarter of Section 6, Township 7 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The project site (refer to Figure 1) is bordered to the west by a multi-family complex and to the north, east, and south by vacant lots. There are no major drainageways located adjacent to the project site. The NECCO Backbone runs parellel to East Suniga Road along the southern boundary of the project site. B. DESCRIPTION OF PROPERTY The Crowne at Suniga project is comprised of ±11.07 acres. The site is currently vacant with native grasses. The existing on-site runoff generally drains from the northwest-to-southeast across flat grades (e.g., <2.00%) into either North Lemay Avenue or an area inlet located in the southeast corner of the site, along the southern property boundary. Runoff leaving the east side of the site is routed to a 15' Type R inlet on the west side on North Lemay Avenue, just north of East Sungia Road. From there, runoff is then routed via a 24” RCP storm drain to the NECCO Backbone, Storm line A1, which outfalls into the Vine Detention Pond. Runoff leaving the southern side of Figure 1 - Vicinity map NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 2 | 11 the site is routed to an area inlet via a swale that runs west-to-east along the north side of East Suniga Road. Runoff is then routed to the NECCO Backbone, Storm Line A1, via an 18” RCP storm drain. Both the the Vine Detention Pond and Storm Line A1 of the NECCO Backbone are defined in the North East College Corridor Outfall (NECCO) Design Report, dated August 2009. The Crowne at Suniga will maintain historical drainage patterns by routing runoff into the Vine Detention Pond via Storm Line A1 of the NECCO Backbone. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey website: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), 79.6% of the site consists of Loveland Clay loam (Hydrologic Soil Group C), 19.2% of the site consists of Nunn clay loam (Hydrologic Soil Group C), and 1.2% of the site consists of Fort Collins loam (Hydrologic Soil Group C). According to “Geotechnical Subsurface Exploration Report Proposed Apartment Complex Developmenet – Graham Property Northeast Corner of 9th Street and Suniga Road” dated June 1, 2022 by Earth Engineering Consultants, LLC shows that groundwater at this location is roughly 7’ deep. There is no major drainageway within or adjacent to the project site. The proposed development will consist of six multi-family buildings containing a total of 260 units. Other proposed improvements include a clubhouse, new concrete drive aisles, new sidewalks, and new landscaping. The proposed land use is multi-family dwellings. This use is permitted in the Medium Density Mixed-use Nebighborhood (M-M-N). Figure 2 - Aerial Photo NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 3 | 11 C. FLOODPLAIN A small portion of the subject property is located within the 500-year FEMA regulatory floodplain. However, the project site is not located within a FEMA-designate 100-year floodplain per Map Number 08069CO981G (Effective date: June 17, 2006). A small portion of the site is located within LOMR 19-08-0751P eff. 06/15/2020. Additionally, the project site is not located in a City of Fort Collins regulated floodplain. DRAIN BASINS AND SUB-BASINS A. MAJOR BASIN DESCRIPTION The Crowne at Suniga Project is located within the City of Fort Collins Dry Creek major drainage basin. Specifically, the project site is situated in the south-central portion of this major drainage basin. This basin is located in north central Fort Collins and has a drainage area of approximately 62 square miles. The land use in the upper and middle portions of the basin is primarily rangeland and irrigated hay meadows and pastures. The majority of the lower basin is developed and includes commercial, industrial and residential uses. The natural channel has disappeared in some areas of the lower basin because of urbanization. Figure 3 - FIRMette Map 08069C0981G NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 4 | 11 B. SUB-BASIN DESCRIPTION The project will outfall into Storm Line A1 of the NECCO Backbone which outfalls into the Vine Detention Pond. The subject site lies within basin 417 as described in the “North East College Corridor Outfall (NECCO) Design Report”. Basin 417 is approximetley 17.0 Acers and was modeled as a devloped basin that drains into the manhole riser A3 of the NECCO Backbone with a release rate of 0.2 cfs per acer. Please refer to appendix E for exerpts from the NECCO Design Report. The existing subject site can be defined with one (1) major sub-basins that encompasses the entire project site. The existing site runoff generally drains from the northwest-to-southeast and into either North Lemay Avenue or an area inlet located in the southeast corner of the site, along the southern property boundary. Runoff leaving the east side of the site is routed to a 15' Type R inlet on the west side on North Lemay Avenue, just north of East Sungia Road. From there, runoff is then routed via a 24” RCP storm drain to the NECCO Backbone, Storm line A1, which outfalls into the Vine Detention Pond. Runoff leaving the southern side of the site is routed to an area inlet via a swale that runs west-to-east along the north side of East Suniga Road. Runoff is then routed to the NECCO Backbone, Storm Line A1, via an 18” RCP storm drain. The project site does not receive runoff from contiguous off-site properties. DRAINAGE DESIGN CRITERIA A. ORIGINAL PROVISIONS AND PREVIOUS STUDIES After coordination with City staff on 2/13/2023, the stormwater design for the Crowne at Suniga will use the 2-year release rate as prescribed by the NECCO Design Report, but with the understanding that basins OS1-OS4 are fringe basins and are mostly pervious and therefore will be allowed to free release into adjacent curb & gutter which will convey runoff into the Storm Line A1 of the NECCO Backbone. The rest of the site will be captured, treated, and detained per the FCSWCM with a release rate of 0.2 cfs per acre which will apply only to the interior basins and not the mostly pervious fringe basins previously discussed. The max release rate for Crowne at Suniga is 1.86 cfs. This was calculated using the 0.2 cfs/acre from the NECCO report and multiplying it by the area that is able to be captured (9.28 acres). Refer to Major Basin SC in the Proposed Rational Calculations spreadsheet found in Appendix A for additional clarification. Please refer to Appendix E for excerpts from previous drainage studies. Complete copies can be provided at request. B. STORMWATER MANAGEMENT STRATEGY The overall stormwater management strategy employed with the Crowne at Suniga utilizes the "Four Step Process" to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 5 | 11 Step 1 – Employ Runoff Reduction Practices. Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the current use of implementing multiple Low Impact Development (LID) strategies, including: · Providing vegetated open areas throughout the site to reduce the overall impervious area and to minimize directly connected impervious areas. · Routing runoff through the drain rock within the Stormtech system to increase concentration-time and promote infiltration. Step 2 – Implement BMPs that Provide a Water Quality Capture Volume (WQCV) with Slow Release. The efforts taken in Step 1 will help to minimize excess runoff from frequently occurring storm events; however, urban development of this intensity will still have stormwater runoff leaving the site. Water quality treatment will occur in the Stomtech Isolator chambers on the south side of the site. Step 3 – Stabilize Drainageways. As stated in Section I. B. 6. above, there is no major drainageway adjacent to the subject site. While this step may not seem applicable to the Crowne at Suniga, the proposed project indirectly helps achieve stabilized drainageways, nonetheless. Once again, site selection has a positive effect on stream stabilization. Developing an infill site with existing stormwater infrastructure, combined with LID and DCIA strategies, reduces the likelihood of bed and bank erosion. Furthermore, this project will pay one-time stormwater development fees and ongoing monthly stormwater utility fees, both of which help achieve Citywide drainageway stability. Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to industrial and commercial developments. However, trash will be stored internal to buildings, this will reduce the potential impacts of garbage making its way downstream. C. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS The project site falls within the NECCO report boundary. Therefore, Crowne at Suniga must follow the criteria set forth by the NECCO report dated August, 2009. Crowne at Suniga is responsible for detention, water quality, and LID. The site plan is constrained on all three sides by public streets. It is bound by 9th Street to the west, East Suniga Road to the south, and North lemay Avenue to the East and North. D. HYDROLOGICAL CRITERIA The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the FCSCM, serves as the source for all hydrologic computations associated with the Crowne at Suniga development. Tabulated data contained in Table 3.4-1 has been utilized for Rational Method runoff calculations. The Rational Method has been employed to compute stormwater runoff utilizing coefficients contained in Tables RO-11 and RO-12 of the FCSCM. The Rational Formula-based Modified Federal Aviation Administration (FAA) procedure has been utilized for detention storage calculations. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 6 | 11 Three separate design storms have been utilized to address distinct drainage scenarios. The first event analyzed is the "Minor" or "Initial" Storm, with a 2-year recurrence interval. The second event considered is the "Major Storm," which has a 100-year recurrence interval. The final event analyzed was the 10-year recurrence interval for comparative analysis only. E. HYDRAULIC CRITERIA The drainage facilities proposed with the Crowne at Suniga project are designed in accordance with criteria outlined in the NECCO Backbone Design Report, FCSCM and/or the Mile High Flood District's (UDFCD) Urban Storm Drainage Criteria Manual. As stated in Section I. C. 1. above, the subject property is not located within a FEMA 100-year or a City of Fort Collins designated floodplain. F. FLOODPLAIN REGULATIONS COMPLIANCE As stated in Section I. C. 1. above, the subject property is not located within a FEMA 100-year or a City of Fort Collins designated floodplain. G. MODIFICATIONS OF CRITERIA No formal modifications are requested at this time. H. CONFORMANCE WITH LOW IMPACT DEVELOPMENT (LID) The project site will conform with the requirement to treat a minimum of 75% of newly or modified impervious area using an LID technique. Please see Appendix C for LID design information, table, and exhibit(s). As shown in the LID table provided in the appendix, 98% of the proposed site will receive LID Treatment, which exceeds the minimum required. I. SIZING OF LID FACILITIES The Stormtech isolator chambers were sized by determining the required water quality capture volume (WQCV) for Major Basin SC. A 12-hour drain time was used in this calculation. Once the WQCV was identified, the minimum number of vaults needed to achieve this volume was calculated. The required WQCV for Major Basin SC is 13,691 cf . A minimum of 60, MC-7200 chambers will be required to meet the storage needs and will supply 16,038 cf of WQCV. Each isolator row will have an inspection port and a Nyloplast basin at the end for easy maintenance and cleanout. A volume calculation utilizing the WQ flow rate into the chamber and the calculated release rate through the fabric was completed. The number of chambers has been increased as needed to confirm the resulting volume is provided within the empty volume of the uderground chambers. This is intended to ensure the chambers do not become overwhelmed in the water quality storm event before "discharging" flows into the surrounding aggregates. For additional clarification, please refer to Appendix C. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 7 | 11 DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT The main objective of the Crowne at Suniga drainage design is to maintain existing drainage patterns and to not adversely impact downstream infrastructure. No notable off-site runoff passes directly through the project site. A list of tables and figures used within this report can be found in the Table of Contents at the front of this document. The tables and figures are located within the sections to which the content best applies. Drainage for the project site has been analyzed using two (2) Major Drainage Basins, designated as Basins SC, & OSC. Both basins have associated sub-basins. The drainage patterns anticipated for the basins are further described below. Major Basin SC Major Basin SC (Stormtech Combined) has 23 sub-basins A-H & R1-R15. Sub-basins A-H consist of asphalt & concrete paving, and landscaping. Sub-basins R1-R15 consist of building roofs only. Major Basin SC has a total area of 9.28 acres and an impervious value of 84%. All runoff generated within Major Basin SC is routed via a combination of overland flow, storm line conveyance, and curb and gutter routing to the Stormtech system. Major Basin SC will receive LID treatment and detention within the Stormtech system. After being treated and detained by the Stormtech system runoff from Major Basin SC will be routed to the NECCO Backbone via an HDPE pipe that is connected to a proposed manhole, which will replace the existing area inlet located in the south-east portion of the site. Major Basin OSC Major Basin OSC (off-Site Combined) has four (4) sub-basins (OS1-OS4) and is associated with the outer permitter of the Crowne at Suniga project site. Major Basin OSC has a total area of 1.79 acres and an impervious value of 6%. Major Basin OSC consists of primarily landscaping and some concrete and asphalt paving. All runoff generated within Major Basin OSC is routed via a combination of overland flow, storm line conveyance, and curb and gutter routing to existing inlets located on 9th street, East Suniga Road, & North Lemay Avenue. These existing inlets outfall into the NECCO Backbone. Runoff generated in Major Basin OSC is negligible and will not have an adverse impact on downstream infrastructure. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. In addition, excerpts from earlier drainage reports referenced in this Section can be found in Appendix E. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 8 | 11 B. SPECIFIC DETAILS As mentioned in Section III.A. the historical 2-year release rate, as perscribed by the NECCO Design Report, will be used as the allowable release rate for the project site. City staff agreed that the Major Basin OSC is mostly pervious and therefore will be allowed to free release into adjacent curb & gutter. However, Major Basin OSC’s area of 1.79 acres will be subtracted from the the project sites total area of 11.07 acres and the remaining area of 9.28 acres (Major Basin SC) will be multiplied by the perscirbed 0.2 cfs/acre to obtain the release rate from the Stormtech system. See Table 1. below. Max Release Rate Calculation by Area Project Site Area (acres) 11.07 Major Basin OSC Area (acres) 1.79 Major Basin SC Area (acres) 9.28 Max Release Rate (cfs) (9.28 ac x 0.2 cfs/ac) 1.86 Table 1 - Maximum release rate calculated by area. LID treatment will be provided for Major Basin SC within the Stormtech System. LID Summary Table Area (ac) % of Area Total Area Treated 9.28 84% Total Area Not Being Treated by LID 1.79 16% Table 2 - Summary of new impervious areas being treated by LID The area that is not getting treated by LID is unable to be captured and routed to the Stormtech system for a few reasons. A. Existing sanitary lines in this area are very shallow and it makes it impossible to have storm lines that are capable of bucking grade all the way back to the Stormtech system. B. The site is bordered by existing easements and Crowne at Suniga is unable to modify the grading in these areas that allow for drainage to flow back into the site. It should be noted that the areas that are not getting LID treatment are mostly landscapinG and thus will have negligible impact on downstream water quality. NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY 9 | 11 CONCLUSIONS A. COMPLIANCE WITH STANDARDS The design elements comply without the need for variances and meet all LID requirements. The drainage design proposed for the Crowne at Suniga complies with the City of Fort Collins Stormwater Criteria Manual as well as the NECCO report. There are no FEMA 100-year regulatory floodplains associated with the Crowne at Suniga development. The drainage plan and stormwater management measures proposed with the Crowne at Suniga project are compliant with all applicable State and Federal regulations governing stormwater discharge. B. DRAINAGE CONCEPT The drainage design proposed with this project will insure that all downstream infrastructure is not adversely impacted with this development. The Crowne at Suniga project will provide on- site detention and LID treatment for runoff. The Crowne at Suniga development will not impact the Master Drainage Plan recommendations for the Dry Creek Major Drainage Basin. REFERENCES 1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, adopted by Ordinance No. 159, 2018, and referenced in Section 26-500 of the City of Fort Collins Municipal Code. 2. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 3. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. 4. Geotechnical Subsurface Exploration Report Proposed Apartment Complex Development – Graham Property Northeast Corner of 9th Street and Suniga Road, Earth Engineering Consultants, Windsor, Colorado, June 2022 5. North East College Corridor Outfall (NECCO) Design Report, Ayres Associates, Fort Collins, Colorado, August 2009 NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINAY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX A HYDROLOGIC COMPUTATIONS CHARACTER OF SURFACE1: Percentage Impervious 2-yr Runoff Coefficient 10-yr Runoff Coefficient 100-yr Runoff Coefficient Developed Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00 Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Landscape or Pervious Surface Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.35 0.44 Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.25 0.25 0.31 Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.15 0.19 Notes: Basin ID Basin Area (ac) Area of Lawns (ac) Composite % Imperv. 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient EX 11.08 11.08 2%0.25 0.25 0.31 2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2 1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3 EXISTING BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Overland Flow, Time of Concentration: Channelized Flow, Time of Concentration: Total Time of Concentration : T c is the lesser of the values of Tc calculated using T c = T i + T t C2 C100 Length, L (ft) Slope, S (%) Ti2 Ti100 Length, L (ft) Slope, S (%) Roughness Coefficient Assumed Hydraulic Radius Velocity, V (ft/s) Tt (min)Tc (Eq. 3.3-5) Tc2 = Ti +Tt Tc100 = Ti +Tt Tc2 Tc100 EX 0.25 0.31 488 0.81% 37.7 35.1 160 1.27% 0.013 0.08 2.45 1.1 13.6 38.8 36.2 13.6 13.6 EXISTING DIRECT TIME OF CONCENTRATION Channelized Flow Design Point Basin Overland Flow Time of Concentration Frequency Adjustment Factor: (Equation 3.3-2 FCSCM) (Equation 5-5 FCSCM) (Equation 5-4 FCSCM) (Equation 3.3-5 FCSCM) Table 3.2-3 FCSCM Therefore Tc2=Tc10 Rational Method Equation: Rainfall Intensity: EX 11.08 13.6 13.6 0.25 0.31 1.95 3.34 6.82 5.40 9.25 23.40 Intensity, i2 (in/hr) Intensity, i100 (in/hr) EXISTING RUNOFF COMPUTATIONS Design Point Basin(s)Area, A (acres) Tc2 (min) Flow, Q2 (cfs) Flow, Q100 (cfs) C2 C100 IDF Table for Rational Method - Table 3.4-1 FCSCM Intensity, i10 (in/hr) Flow, Q10 (cfs) Tc100 (min) ()()()AiCCQf= BASIN TOTAL AREA (acres) Tc2 (min) Tc100 (min) C2 C100 Q2 (cfs) Q100 (cfs) EX 11.08 13.6 13.6 0.25 0.31 5.40 23.40 Rational Flow Summary | Existing Basin Flow Rates 2/8/20234:23 PM P:\1893-001\Drainage\Hydrology\1893-001_Existing Rational Calcs (FCSCM).xlsx\Summary Tables Project Site Area (acres)11.07 Major Basin OSC Area (acres)1.79 Major Basin SC Area (acres)9.28 Max Release Rate (cfs) (9.28 ac x 0.2 cfs/ac)1.86 Max Release Rate Calculation by Area Table 1. Maximum release rate calculated by area. CHARACTER OF SURFACE1: Percentage Impervious 2-yr Runoff Coefficient 10-yr Runoff Coefficient 100-yr Runoff Coefficient Developed Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00 Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00 Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63 Landscape or Pervious Surface Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.35 0.44 Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.25 0.25 0.31 Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.15 0.19 Notes: Basin ID Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Rooftop (ac) Area of Lawns (ac) Composite % Imperv. 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient A 0.48 0.37 0.05 0.00 0.06 88%0.86 0.86 0.91 B 0.37 0.27 0.04 0.00 0.05 86%0.85 0.85 0.90 C 0.83 0.66 0.05 0.00 0.12 86%0.85 0.85 0.90 D 1.23 0.84 0.11 0.00 0.27 78%0.79 0.79 0.85 E 0.34 0.00 0.34 0.00 0.00 100%0.95 0.95 1.00 F 0.75 0.35 0.15 0.00 0.25 68%0.72 0.72 0.77 G 0.44 0.31 0.08 0.00 0.06 87%0.86 0.86 0.91 H 1.83 1.31 0.21 0.00 0.31 83%0.83 0.83 0.88 R1 0.16 0.00 0.00 0.16 0.00 90%0.95 0.95 1.00 R2 0.12 0.00 0.00 0.12 0.00 90%0.95 0.95 1.00 R3 0.24 0.00 0.00 0.24 0.00 90%0.95 0.95 1.00 R4 0.17 0.00 0.00 0.17 0.00 90%0.95 0.95 1.00 R5 0.14 0.00 0.00 0.14 0.00 90%0.95 0.95 1.00 R6 0.22 0.00 0.00 0.22 0.00 90%0.95 0.95 1.00 R7 0.15 0.00 0.00 0.15 0.00 90%0.95 0.95 1.00 R8 0.15 0.00 0.00 0.15 0.00 90%0.95 0.95 1.00 R9 0.20 0.00 0.00 0.20 0.00 90%0.95 0.95 1.00 R10 0.26 0.00 0.00 0.26 0.00 90%0.95 0.95 1.00 R11 0.14 0.00 0.00 0.14 0.00 90%0.95 0.95 1.00 R12 0.34 0.00 0.00 0.34 0.00 90%0.95 0.95 1.00 R13 0.24 0.00 0.00 0.24 0.00 90%0.95 0.95 1.00 R14 0.31 0.00 0.00 0.18 0.13 53%0.66 0.66 0.71 R15 0.18 0.00 0.00 0.18 0.00 90%0.95 0.95 1.00 OS1 0.48 0.00 0.02 0.00 0.46 6%0.28 0.28 0.34 OS2 0.56 0.02 0.02 0.00 0.52 9%0.30 0.30 0.36 OS3 0.34 0.00 0.00 0.00 0.34 2%0.25 0.25 0.31 OS4 0.41 0.00 0.01 0.00 0.40 5%0.27 0.27 0.33 MAJOR BASIN SC (STORMTECH, COMBINED)9.28 4.11 1.04 2.88 1.25 84% 0.86 0.86 0.91 MAJOR BASIN OSC (OFF-SITE, COMBINED)1.79 0.02 0.05 0.00 1.72 6% 0.28 0.28 0.34 DEVELOPED BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS 2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2 1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3 Combined Basins Overland Flow, Time of Concentration: Channelized Flow, Time of Concentration: Total Time of Concentration : T c is the lesser of the values of Tc calculated using T c = T i + T t C2 C100 Length, L (ft) Slope, S (%) Ti2 Ti100 Length, L (ft) Slope, S (%) Roughness Coefficient Assumed Hydraulic Radius Velocity, V (ft/s) Tt (min)Tc (Eq. 3.3-5) Tc2 = Ti +Tt Tc100 = Ti +Tt Tc2 Tc100 a1 A 0.86 0.91 59 2.24%2.6 2.1 160 0.87%0.013 0.08 2.03 1.3 11.2 3.9 3.4 5.0 5.0 b1 B 0.85 0.90 44 1.66%2.6 2.1 117 0.61%0.013 0.08 1.69 1.2 10.9 3.8 3.3 5.0 5.0 c1 C 0.85 0.90 130 1.82%4.4 3.5 194 1.07%0.013 0.08 2.25 1.4 11.8 5.8 4.9 5.8 5.0 d1 D 0.79 0.85 161 4.08%4.6 3.7 158 0.60%0.013 0.08 1.68 1.6 11.8 6.2 5.3 6.2 5.3 e1 E 0.95 1.00 210 1.67%3.4 2.3 0 N/A 0.013 0.08 N/A N/A 11.2 3.4 2.3 5.0 5.0 f1 F 0.72 0.77 39 6.17%2.4 2.1 175 0.60%0.013 0.08 1.68 1.7 11.2 4.1 3.8 5.0 5.0 g1 G 0.86 0.91 32 4.84%1.5 1.2 196 0.83%0.013 0.08 1.98 1.6 11.3 3.1 2.8 5.0 5.0 h1 H 0.83 0.88 89 2.18%3.7 3.0 156 1.00%0.013 0.08 2.17 1.2 11.4 4.9 4.2 5.0 5.0 R1 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R2 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R3 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R4 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R5 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R6 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R7 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R8 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R9 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R10 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R11 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R12 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R13 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 R14 0.66 0.71 46 2.19%4.3 3.8 0 N/A N/A N/A N/A N/A 10.3 4.3 3.8 5.0 5.0 R15 0.95 1.00 46 2.19%1.5 1.0 0 N/A N/A N/A N/A N/A 10.3 1.5 1.0 5.0 5.0 os1 OS1 0.28 0.34 71 10.95%5.8 5.4 557 1.01%0.013 0.08 2.19 4.2 13.5 10.1 9.6 10.1 9.6 os2 OS2 0.30 0.36 42 2.29%7.3 6.8 592 0.60%0.013 0.08 1.68 5.9 13.5 13.2 12.6 13.2 12.6 os3 OS3 0.25 0.31 70 6.91%7.0 6.5 379 0.58%0.013 0.08 1.66 3.8 12.5 10.8 10.3 10.8 10.3 os4 OS4 0.27 0.33 42 2.29% 7.6 7.0 592 0.60% 0.013 0.08 1.68 5.9 13.5 13.5 12.9 13.5 12.9 a1 MAJOR BASIN SC (STORMTECH, COMBINED)0.86 0.91 59 2.24% 2.6 2.1 160 0.87% 0.013 0.083 0.20 13.1 10.3 1.5 1.0 5.0 5.0 c1 MAJOR BASIN OSC (OFF- SITE, COMBINED)0.28 0.34 71 10.95% 5.8 5.4 59 9.49% 0.013 0.083 0.67 1.5 12.5 10.1 9.6 10.1 9.6 Combined Basins DEVELOPED DIRECT TIME OF CONCENTRATION Channelized Flow Design Point Basin Overland Flow Time of Concentration Frequency Adjustment Factor: (Equation 3.3-2 FCSCM) (Equation 5-5 FCSCM) (Equation 5-4 FCSCM) (Equation 3.3-5 FCSCM) Table 3.2-3 FCSCM Therefore Tc2=Tc10 Rational Method Equation: Rainfall Intensity: a1 A 0.48 5.0 5.0 0.86 0.91 2.85 4.87 9.95 1.19 2.03 4.39 b1 B 0.83 5.0 5.0 0.85 0.90 2.85 2.85 9.95 2.00 2.00 7.41 c1 C 0.83 5.0 5.0 0.85 0.90 2.85 4.87 9.95 2.00 3.42 7.41 d1 D 0.34 5.3 5.3 0.95 1.00 2.85 2.85 9.95 0.92 0.92 3.39 e1 E 0.34 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.92 1.58 3.39 f1 F 0.44 5.0 5.0 0.86 0.91 2.85 2.85 9.95 1.08 1.08 3.98 g1 G 0.44 5.0 5.0 0.86 0.91 2.85 4.87 9.95 1.08 1.84 3.98 h1 H 0.16 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.45 0.45 1.64 R1 0.16 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.45 0.76 1.64 R2 0.24 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.64 0.64 2.35 R3 0.24 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.64 1.09 2.35 R4 0.14 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.37 0.37 1.37 R5 0.14 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.37 0.64 1.37 R6 0.15 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.41 0.41 1.49 R7 0.15 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.41 0.69 1.49 R8 0.20 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.53 0.53 1.95 R9 0.20 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.53 0.91 1.95 R10 0.14 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.38 0.38 1.40 R11 0.14 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.38 0.65 1.40 R12 0.24 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.64 0.64 2.36 R13 0.24 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.64 1.10 2.36 R14 0.18 5.0 5.0 0.95 1.00 2.85 2.85 9.95 0.49 0.49 1.79 R15 0.18 5.0 5.0 0.95 1.00 2.85 4.87 9.95 0.49 0.83 1.79 os1 OS1 0.56 9.6 9.6 0.30 0.36 2.26 2.26 7.88 0.38 0.38 1.58 os2 OS2 0.56 12.6 12.6 0.30 0.36 2.02 3.45 7.04 0.34 0.58 1.41 os3 OS3 0.41 10.3 10.3 0.27 0.33 2.21 2.21 7.72 0.24 0.24 1.04 os4 OS4 0.41 12.9 12.9 0.27 0.33 2.02 3.45 7.04 0.22 0.38 0.95 MAJOR BASIN SC (STORMTECH, COMBINED) 9.28 5.0 5.0 0.86 0.91 2.85 2.85 9.95 22.74 24.06 84.01 MAJOR BASIN OSC (OFF- SITE, COMBINED)1.79 9.6 9.6 0.28 0.34 2.26 2.26 7.88 1.13 1.38 4.80 DEVELOPED RUNOFF COMPUTATIONS Design Point Basin(s)Area, A (acres) Tc2 (min) Flow, Q2 (cfs) Flow, Q100 (cfs) C2 C100 IDF Table for Rational Method - Table 3.4-1 FCSCM Intensity, i10 (in/hr) Flow, Q10 (cfs) Combined Basins Tc100 (min) Intensity, i2 (in/hr) Intensity, i100 (in/hr) ()()()AiCCQf= BASIN TOTAL AREA (acres) Tc2 (min) Tc100 (min) C2 C100 Q2 (cfs) Q100 (cfs) A 0.48 5.0 5.0 0.86 0.91 1.19 4.39 B 0.83 5.0 5.0 0.85 0.90 2.00 7.41 C 0.83 5.0 5.0 0.85 0.90 2.00 7.41 D 0.34 5.3 5.3 0.95 1.00 0.92 3.39 E 0.34 5.0 5.0 0.95 1.00 0.92 3.39 F 0.44 5.0 5.0 0.86 0.91 1.08 3.98 G 0.44 5.0 5.0 0.86 0.91 1.08 3.98 H 0.16 5.0 5.0 0.95 1.00 0.45 1.64 R1 0.16 5.0 5.0 0.95 1.00 0.45 1.64 R2 0.24 5.0 5.0 0.95 1.00 0.64 2.35 R3 0.24 5.0 5.0 0.95 1.00 0.64 2.35 R4 0.14 5.0 5.0 0.95 1.00 0.37 1.37 R5 0.14 5.0 5.0 0.95 1.00 0.37 1.37 R6 0.15 5.0 5.0 0.95 1.00 0.41 1.49 R7 0.15 5.0 5.0 0.95 1.00 0.41 1.49 R8 0.20 5.0 5.0 0.95 1.00 0.53 1.95 R9 0.20 5.0 5.0 0.95 1.00 0.53 1.95 R10 0.14 5.0 5.0 0.95 1.00 0.38 1.40 R11 0.14 5.0 5.0 0.95 1.00 0.38 1.40 R12 0.24 5.0 5.0 0.95 1.00 0.64 2.36 R13 0.24 5.0 5.0 0.95 1.00 0.64 2.36 R14 0.18 5.0 5.0 0.95 1.00 0.49 1.79 R15 0.18 5.0 5.0 0.95 1.00 0.49 1.79 OS1 0.56 9.6 9.6 0.30 0.36 0.38 1.58 OS2 0.56 12.6 12.6 0.30 0.36 0.34 1.41 OS3 0.41 10.3 10.3 0.27 0.33 0.24 1.04 OS4 0.41 12.9 12.9 0.27 0.33 0.22 0.95 MAJOR BASIN SC (STORMTECH, COMBINED)9.28 5.0 5.0 0.86 0.91 22.74 84.01 MAJOR BASIN OSC (OFF-SITE, COMBINED) 1.79 9.6 9.6 0.28 0.34 1.13 4.80 Rational Flow Summary | Developed Basin Flow Rates Combined Basins 2/13/20231:50 PM P:\1893-001\Drainage\Hydrology\1893-001_Proposed Rational Calcs (FCSCM).xlsx\Summary Tables NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX B B.1 - DETENTION SYSTEM CALCULATIONS B.2 - HYDRAULIC CALCULATIONS – FOR FUTURE USE NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX B.1 DETENTION SYSTEM CALCULATIONS B2 100-yr 0.92 5.00 min Storage 121531 ft3 11.07 acres Max Release Rate =1.86 cfs 2.79 ac-ft Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 30400 1.00 1.86 558 29842 10 7.720 47174 1.00 1.86 1116 46058 15 6.520 59762 1.00 1.86 1674 58088 20 5.600 68439 1.00 1.86 2232 66207 25 4.980 76077 1.00 1.86 2790 73287 30 4.520 82860 1.00 1.86 3348 79512 35 4.080 87260 1.00 1.86 3906 83354 40 3.740 91415 1.00 1.86 4464 86951 45 3.460 95143 1.00 1.86 5022 90121 50 3.230 98687 1.00 1.86 5580 93107 55 3.030 101834 1.00 1.86 6138 95696 60 2.860 104859 1.00 1.86 6696 98163 65 2.720 108036 1.00 1.86 7254 100782 70 2.590 110786 1.00 1.86 7812 102974 75 2.480 113658 1.00 1.86 8370 105288 80 2.380 116347 1.00 1.86 8928 107419 85 2.290 118944 1.00 1.86 9486 109458 90 2.210 121541 1.00 1.86 10044 111497 95 2.130 123649 1.00 1.86 10602 113047 100 2.060 125879 1.00 1.86 11160 114719 105 2.000 128323 1.00 1.86 11718 116605 110 1.940 130401 1.00 1.86 12276 118125 115 1.890 132815 1.00 1.86 12834 119981 120 1.840 134923 1.00 1.86 13392 121531 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. DETENTION VOLUME CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 1893-001 The Crowne at Suniga Project Number : Project Name : Stormtech System - Detention A = Tc = Project Location : Design Point C = Design Storm Storage System : Page 1 of 1 1893-001_Pond_FAA_Fort Collins_Detention Volume.xls User Inputs Chamber Model: MC-7200 Outlet Control Structure: Yes Project Name: Crowne at Suniga Engineer: S. King KING Project Location: Colorado Measurement Type: Imperial Required Storage Volume: 121531 cubic ft. Stone Porosity: 40% Stone Foundation Depth: 9 in. Stone Above Chambers: 12 in. Average Cover Over Chambers: 24 in. Design Constraint Dimensions:(110 ft. x 292 ft.) Results System Volume and Bed Size Installed Storage Volume: 123008.69 cubic ft. Storage Volume Per Chamber: 175.90 cubic ft. Number Of Chambers Required: 441 Number Of End Caps Required: 22 Chamber Rows: 11 Maximum Length:282.21 ft. Maximum Width: 101.77 ft. Approx. Bed Size Required: 28127.46 square ft. System Components Amount Of Stone Required: 4127 cubic yards Volume Of Excavation (Not Including Fill): 7032 cubic yards Total Non-woven Geotextile Required:8200 square yards Woven Geotextile Required (excluding Isolator Row): 192 square yards Woven Geotextile Required (Isolator Row): 644 square yards Total Woven Geotextile Required:835 square yards Impervious Liner Required:0 square yards NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX B.2 HYDRAULIC CALCULATIONS – FOR FUTURE USE NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX C WATER QUALITY/LID COMPUTATIONS Project Title Date: Project Number Calcs By: City Basins 0.8 WQCV = Watershed inches of Runoff (inches)84% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100)0.284 in A =11.07 ac V = 0.3143 ac-ft V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) 13691 cu. ft. Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event The Crowne at Suniga February 13, 2023 1893-001 S. King Fort Collins Stormtech LID Pond 0.231 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr ()iii78.019.10.91aWQCV 23 +-= ()iii78.019.10.91aWQCV 23 +-= 12 hr 1.20 WQCV 12 ∗ Pond No : Stormtech Pond WQ 0.92 5.00 min 10453 ft3 11.07 acres 0.24 ac-ft Max Release Rate =2.35 cfs Time (min) Ft Collins WQ Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustmen t Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 1.425 4354 1.00 2.35 705 3649 10 1.105 6752 1.00 2.35 1409 5343 15 0.935 8570 0.67 1.57 1409 7161 20 0.805 9838 0.63 1.47 1761 8077 25 0.715 10923 0.60 1.41 2114 8809 30 0.650 11916 0.58 1.37 2466 9450 35 0.585 12512 0.57 1.34 2818 9693 40 0.535 13077 0.56 1.32 3170 9906 45 0.495 13611 0.56 1.30 3523 10089 50 0.460 14054 0.55 1.29 3875 10179 55 0.435 14620 0.55 1.28 4227 10392 60 0.410 15032 0.54 1.27 4580 10453 65 0.385 15292 0.54 1.26 4932 10360 70 0.365 15613 0.54 1.26 5284 10329 75 0.345 15811 0.53 1.25 5636 10175 80 0.330 16132 0.53 1.25 5989 10143 85 0.315 16361 0.53 1.24 6341 10020 90 0.305 16774 0.53 1.24 6693 10080 95 0.290 16835 0.53 1.24 7046 9789 100 0.280 17110 0.53 1.23 7398 9712 105 0.270 17324 0.52 1.23 7750 9574 110 0.260 17476 0.52 1.23 8102 9374 115 0.255 17919 0.52 1.23 8455 9465 120 0.245 17965 0.52 1.22 8807 9158 *Note: Using the method described in FCSCM Chapter 6 Section 2.3 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 1893-001 The Crowne at Suniga Project Number : Project Name : Stormtech LID Pond Page 1 of 1 1893-001 LID Chamber Summary.xlsx Vault ID Total Required WQ Volume (cf) Flow, WQ (cfs) Chamber Type Chamber Release Ratea (cfs) Chamber Volumeb (cf) Installed Camber w/ Aggregatec (cf) Mimimum No. of Chambersd Total Release Ratee (cfs) Required Storage Volume by FAA Method (cf) Mimimum No. of Chambersf Storage Provided within the Chambersg (cf) Minimum Total Installed System Volumeh (cf) Stormtech LID Pond 13691 11.37 MC-7200 0.045 175.90 267.30 52 2.35 10453 60 10554 16038 a. Release rate per chamber, limited by flow through geotextile with accumulated sediment. b. Volume within chamber only, not accounting for void spaces in surrounding aggregate. c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit. d. Number of chambers required to provide full WQCV within total installed system, including aggregate. e. Release rate per chamber times number of chambers. f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage). g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume. h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV. Chamber Configuration Summary P:\1893-001\Drainage\LID\1893-001 LID Chamber Summary.xlsx Area (ac)% of Area Total Area Treated 9.28 84% Total Area Not Being Treated by LID 1.79 16% LID Summary Table Table 2 - Summary of new impervious areas being treated by LID DDDDDDDDDDUDUDUDUDUDMONITORING WELL TRAFFIC RATED TFTF TFTFTFTFBUILDING 1000 DFC NORTH FIELD LLC 981 LINDENMEIER ROAD EAST SUNIGA ROADNORT H LE MAY AVE N UE GRAHAM JOHN C / GINGER L 1100 E VINE DRIVE BUILDING 2000 BUILDING 3000 BUILDING 4000 BUILDING 5000 BUILDING 6000 DOG PARK 500-YEAR FLOODPLAIN STORM DRAIN (TYP.) AREA INLET (TYP.) EXISTING NECCO BACKBONE STORM DRAIN STORMTECH MC-7200 SYSTEM 63 ISOLATOR CHAMBERS & 441 DETENTION CHAMBERS WATER QUALITY BASIN w/ WEIR EXISTING NECCO STORM DRAIN A3 EXISTING TYPE R INLET EXISTING TYPE R INLET EXISTING AREA INLET LID EXHIBIT FORT COLLINS, CO CROWNE AT SUNIGA E N G I N E E R N GI EHTRON R N 02.22.23 P:\1893-001\DWG\DRNG\1893-001_LID.DWG ( IN FEET ) 0 1 INCH = 100 FEET 100 100 200 300 NOTES: 1.REFER TO THE CROWNE AT SUNIGA - UTILITY PLANS FOR ADDITIONAL CLARIFICATION ON BASIN BREAKDOWNS, GRADING, AND UTILITY SIZING. LID SUMMARY AND LEGEND: LID Summary Table Area (ac)% of Area Total Area Treated 9.28 84% Total Area Not Being Treated by LID 1.79 16% NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX D EROSION CONTROL REPORT NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY EROSION CONTROL REPORT EROSION CONTROL REPORT A comprehensive Erosion and Sediment Control Plan (along with associated details) will be included with the final construction drawings. It should be noted; however, any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed, or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing and/or wattles along the disturbed perimeter, gutter protection in the adjacent roadways, and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Utility Plans will also contain a full-size Erosion Control Plan as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in any existing Development Agreement(s) of record, as well as the Development Agreement, to be recorded prior to issuance of the Development Construction Permit. Also, the Site Contractor for this project may be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater Program, before commencing any earth disturbing activities. Prior to securing said permit, the Site Contractor shall develop a comprehensive Storm Water Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance of construction BMPs. NNORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX APPENDIX E EXCERPTS FROM PREVIOUS REPORTS AND USDA SOILS REPORT DRAFT FINAL NORTH EAST COLLEGE CORRIDOR OUTFALL (NECCO) DESIGN REPORT Prepared for City of Fort Collins Utilities 700 Wood Street Fort Collins, Colorado 80521 3.7 Ayres Associates • Basin 412 is currently an undeveloped basin consisting of the Raptor Center. It was modeled as a developed basin that drains into proposed Manhole A1. The storm sewer that would be required to connect this basin with the proposed manhole was not designed with the NECCO project. • Basin 413 is currently an undeveloped basin. It was modeled as a developed basin that drains into the proposed Regional Detention Pond. The storm sewer that would drain this basin to the proposed detention facility was not designed with the NECCO project. The future pipe will cross the re-aligned Vine Drive. This pipe crossing must take into account the GWET and NEWT waterline clearances. These clearances are very critical. • Basin 414 consists of the Alta Vista development. If redeveloped, the basin was modeled as discharging into proposed Manhole Riser A4 (or downstream of transition A1). The storm sewer that would be required to connect this basin with the proposed manhole was not designed with the NECCO project. • Basin 417 is currently an undeveloped basin. It was modeled as a developed basin that drains into proposed Manhole Riser A3. • Basin 417 is currently an undeveloped basin. It will drain into the future east Vine Diversion Channel. • Basin 418 is currently an undeveloped basin. It was modeled as a developed basin that drains downstream of the proposed Manhole Riser A2. • Basin 419 is currently an undeveloped basin. It will drain into the future east Vine Diversion Channel. • Basin 420 is currently an undeveloped basin. It will drain into the future east Vine Diversion Channel. • Basin 421 is currently an undeveloped basin. It will drain into the future east Vine Diversion Channel. • Basin 422 is currently an undeveloped basin. It will drain into the future east Vine Diversion Channel. • Basin 424 drains overland to proposed Inlet B6A. If redeveloped, the basin will continue to drain to the inlet. This basin drains through basins 324 and 326 and will need to accounted for in the drainage of these basins. • Basin 426 is currently an undeveloped basin. It was modeled as a developed basin that drains to proposed Manhole B5. Basin 226 drains through this basin and will need to be accounted for in the redevelopment of basin 426. • Basin 427 drains overland to proposed Inlet B6A. • Basin 510 currently drains into the Lake Canal. This basin was not further analyzed with the NECCO project. 4.1 Ayres Associates 4. FINAL STORM SEWER DESIGN AND HYDRAULIC ANALYSIS ModSWMM was used to develop the basin hydrographs only, while EPA SWMM 5.0.013 was used for the hydraulic routing of the basins in the developed condition with proposed facilities model. EPA SWMM was used to model the inflows and outflows of the existing Evergreen West and Redwood Ponds as well as model the proposed storm sewer lines A, B, C, and E. The input requirements for the EPA SWMM 5.0.013 model include the following: • Pipe lengths, diameters, inverts and material • Reservoir stage vs. area information for each pond • Inflow hydrographs – These were developed from the ModSWMM analysis described previously • Geometry of outlet structures, i.e., weirs, orifices etc. UD Inlet version 2.14a was used to size inlets for each system. The City of Fort Collins Storm Drainage Criteria was followed to determine the street carrying capacity and encroachment for the 100-year storm event. The same criterion was followed to size the inlets along re-aligned Vine Drive for the 10-year storm event. Snout oil-water debris separators are incorporated into the design of the inlets along realigned Vine Drive (refer to Appendix D for the inlet calculations). Following is a list summarizing the detention and water quality assumption made for each basin during the final design process: • Undeveloped properties east of Redwood require future on-site detention and water quality. These basins were modeled assuming a proposed detention facility 100-year release rate of 0.2 cfs/acre. - Basins: 113, 114*, 115, 116, 117, 313, 320, 412, 417, 418, 419*, 420*, 421*, 422* *These basins do not discharge into the proposed NECCO Storm Sewer. • The undeveloped area south of Conifer Street, west of Redwood and north of the proposed re-aligned Vine Drive would discharge into the regional pond without on-site detention or water quality. - Basins: 126, 127, 327*, 408, 526, 726 *Proposed Regional Detention Pond • Dry Creek, behind Autozone and south to the Proposed East Vine Drive, will be filled in. Currently basins 407, 316 and 315 drain into Dry Creek. Currently Basin 407 drains into an existing detention pond. This pond will be connected into the proposed storm sewer. This pond can be removed as long as basin 407 ultimately discharges into the proposed NECCO storm sewer system. Currently Basin 316 drains into an existing detention pond. This pond will be removed with the construction of the re-aligned Vine Drive. The flow that currently travels to the southern pond will be conveyed overland to Vine Drive where it will be collected in the proposed storm sewer. LEGENDDRAINAGE BASINBASIN NUMBERBASIN AREA (ACRES)EXHIBIT 4.2FUTURE DETENTION AND WATER QUALITY REQUIREMENTSRESTRICT AMOUNT OF RUNOFFTO EXISTING CONDITIONS IFRE-DEVELOPED. WATER QUALITYPROVIDED IN REDWOOD PONDREQUIRE FUTURE ON-SITEDETENTION & WATERQUALITY. RELEASE RATE @ 0.20 cfs/acreREQUIRE FUTURE ON-SITEDETENTION.WATER QUALITY PROVIDEDIN REGIONAL POND.FUTURE RE-ALIGNED VINEDRIVE. WATER QUALITYPROVIDED WITH SNOUTS.DISCHARGE INTOREGIONAL POND WITHOUTFUTURE DETENTION ORWATER QUALITY.RESTRICT AMOUNT OF RUNOFFTO EXISTING CONDITIONS IFRE-DEVELOPED. FUTURE WATERQUALITY REQUIRED.RESTRICT AMOUNT OF RUNOFFTO EXISTING CONDITIONS IFRE-DEVELOPED. WATER QUALITYPROVIDED IN REGINAL POND.BASIN 103: NO DETENTION ORWATER QUALITY REQURED IFDISCHARGING INTOEVERGREEN WEST PONDCOLLEGE AVENUERED CEDAR CIRCLELEMAY AVENUE DRY CREEK BRISTLECONE DRIVECONIFER STREETNOKOMIS COURTBLUE SPRUCE DRIVE CONIFER STREETLUPINE DRIVEREDWOODPONDREGIONALPONDREDWOOD STREETCOLLEGE AVENUEJEROME STREETBONDELL STREET OSIANDER STREETEAST VINE DRIVE70.0 ac68.2 ac13.2 ac18.5 ac8.7 ac29.3 ac11.4 ac9.8 ac11.4 ac4.8 ac16.4 ac3.3 ac1.3 ac31.6 ac52.7 ac21.3 ac7.4 ac18.1 ac17.0 ac2.5 ac2.7 ac2.0 ac4.6 ac2.5 ac13.1 ac3.9 ac13.7 ac1.8 ac0.2 ac7.2 ac6.0 ac3.8 ac0.6 ac2.4 ac5.2 ac1.6 ac2.6 ac35.7 ac2.6 ac1.8 ac1.8 ac1.6 ac1.2 ac0.7 ac4.2 ac2.6 ac13.6 ac13.0 ac8.6 ac7.1 ac5.1 ac4.5 ac4.2 ac10.9 ac8.2 ac19.2 ac16.0 ac32.4 ac17.5 ac9.8 ac16.6 ac29.3 ac6.0 ac10.3 ac5.9 ac1.5 ac1.3 ac21.2 ac1.2 ac1.5 ac1.1 ac1.1 ac8.2 ac1.0 ac8.6 ac5.2 ac14.8 ac2.0 ac1.6 ac3.3 ac1.4 ac5.3 ac1.2 ac1.0 ac2.7 ac2.2 ac3.9 ac3.3 ac3.4 ac4.4 ac7.9 ac0.2 ac4.2 ac1.1 ac1.7 ac2.4 ac2.0 ac1.0 ac36.2 ac5.5 ac49.1 ac 4.4 Ayres Associates Figure 4.1. Proposed storm infrastructure. GEOTECHNICAL SUBSURFACE EXPLORATION REPORT PROPOSED APARTMENT COMPLEX DEVELOPMENT - GRAHAM PROPERTY NORTHEAST CORNER OF 9TH STREET AND SUNIGA ROAD FORT COLLINS, COLORADO EEC PROJECT NO. 1222009 Prepared for: Crowne Partners, Inc. 505 North 20th Street - Suite 1150 Birmingham, AL 35203 Attn: Mr. Cary Levow (clevow@crownepartners.com) Prepared by: Earth Engineering Consultants, LLC 4396 Greenfield Drive Windsor, Colorado 80550 4396 GREENFIELD DRIVE W INDSOR, COLORADO 80550 (970) 545-3908 FAX (970) 663-0282 June 1, 2022 Crowne Partners, Inc. 505 North 20th Street - Suite 1150 Birmingham, AL 35203 Attn: Mr. Cary Levow (clevow@crownepartners.com) Re: Geotechnical Subsurface Exploration Report Proposed Apartment Complex Development – Graham Property Approximate 11-Acres Parcel – Northeast Corner of 9th Street and Suniga Road Fort Collins, Colorado EEC Project No. 1222009 Mr. Levow: Enclosed, herewith, are the results of the geotechnical subsurface exploration completed by Earth Engineering Consultants, LLC (EEC) for the proposed multi-family apartment complex planned for construction in Fort Collins, Colorado. For this exploration, EEC personnel advanced twenty- one (21) soil borings to depths of approximately 4 to 13 feet below present site grades at pre- selected locations within the various proposed building footprints and associated on-site pavement improvements. This exploration was completed in general accordance with our proposal dated January 17, 2022. In summary, the subsurface conditions encountered beneath the surficial vegetation/fescue grass generally consisted of cohesive to slightly cohesive lean clay with sand to silty/clayey sand soils extending to granular gravel/sand with silt/clay soils at depths of approximately ½ to 8 feet. The cohesive soils were generally dry to moist and soft/very loose to stiff/dense and exhibited nil to low with an occasional high swell potential (at boring B-15) and slight tendency to hydro- compact at current moisture and density conditions. Gravel/sand with silt/clay soils were encountered below the cohesive to slightly cohesive soils and extended to the depths explored at approximately 4 to 13 feet below the site grades. Zones of larger cobbles were also encountered in the gravel/sand soils. The gravel/sand soils were generally dry to moist and medium dense to very dense. Groundwater was observed in the two deepest borings; B-14 and B-20 which advanced to depths of approximately 13 and 10 feet below the site grades at depths of approximately 7 to 9 feet, respectively. Groundwater was not observed in the rest of the borings advanced to maximum depths of approximately 7 feet below the ground surface at the time of drilling. 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 The Crowne at Suniga Natural Resources Conservation Service January 24, 2023 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 35—Fort Collins loam, 0 to 3 percent slopes..............................................13 64—Loveland clay loam, 0 to 1 percent slopes...........................................14 76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................15 References............................................................................................................17 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 449424044942904494340449439044944404494490449454044945904494640449424044942904494340449439044944404494490449454044945904494640495090 495140 495190 495240 495290 495340 495390 495090 495140 495190 495240 495290 495340 495390 40° 36' 9'' N 105° 3' 29'' W40° 36' 9'' N105° 3' 15'' W40° 35' 55'' N 105° 3' 29'' W40° 35' 55'' N 105° 3' 15'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 30 60 120 180 Meters Map Scale: 1:2,050 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 17, Sep 7, 2022 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 2, 2021—Aug 25, 2021 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 35 Fort Collins loam, 0 to 3 percent slopes 0.1 1.2% 64 Loveland clay loam, 0 to 1 percent slopes 8.7 79.6% 76 Nunn clay loam, wet, 1 to 3 percent slopes 2.1 19.2% Totals for Area of Interest 10.9 100.0% 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 35—Fort Collins loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlnc Elevation: 4,020 to 6,730 feet Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 46 to 48 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Fort collins and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins Setting Landform:Stream terraces, interfluves Landform position (three-dimensional):Interfluve, tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Pleistocene or older alluvium and/or eolian deposits Typical profile Ap - 0 to 4 inches: loam Bt1 - 4 to 9 inches: clay loam Bt2 - 9 to 16 inches: clay loam Bk1 - 16 to 29 inches: loam Bk2 - 29 to 80 inches: loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.20 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:12 percent Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Nunn Percent of map unit:10 percent Landform:Stream terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY002CO - Loamy Plains Hydric soil rating: No Vona Percent of map unit:5 percent Landform:Interfluves Landform position (three-dimensional):Interfluve, side slope Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY024CO - Sandy Plains Hydric soil rating: No 64—Loveland clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpx9 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 Loveland and similar soils:90 percent Minor components:10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Loveland Setting Landform:Flood plains, stream terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Alluvium Typical profile H1 - 0 to 15 inches: clay loam H2 - 15 to 32 inches: loam H3 - 32 to 60 inches: very gravelly sand Custom Soil Resource Report 14 Properties and qualities Slope:0 to 1 percent Depth to restrictive feature:More than 80 inches Drainage class:Poorly drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to 0.60 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding:OccasionalNone Frequency of ponding:None Calcium carbonate, maximum content:15 percent Maximum salinity:Very slightly saline to slightly saline (2.0 to 4.0 mmhos/cm) Available water supply, 0 to 60 inches: Moderate (about 7.5 inches) Interpretive groups Land capability classification (irrigated): 3w Land capability classification (nonirrigated): 3w Hydrologic Soil Group: C Ecological site: R067BY036CO - Overflow Hydric soil rating: No Minor Components Aquolls Percent of map unit:5 percent Landform:Swales Hydric soil rating: Yes Poudre Percent of map unit:5 percent Ecological site:R067BY036CO - Overflow Hydric soil rating: No 76—Nunn clay loam, wet, 1 to 3 percent slopes Map Unit Setting National map unit symbol: jpxq 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, wet, and similar soils:90 percent Minor components:10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Custom Soil Resource Report 15 Description of Nunn, Wet Setting Landform:Alluvial fans, stream terraces 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 47 inches: clay H3 - 47 to 60 inches: gravelly loam Properties and qualities Slope:1 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat poorly drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table:About 24 to 36 inches Frequency of flooding:NoneRare Frequency of ponding:None Calcium carbonate, maximum content:10 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: High (about 9.9 inches) Interpretive groups Land capability classification (irrigated): 2w Land capability classification (nonirrigated): 3s Hydrologic Soil Group: C Ecological site: R067BY038CO - Wet Meadow Hydric soil rating: No Minor Components Heldt Percent of map unit:6 percent Ecological site:R067BY042CO - Clayey Plains Hydric soil rating: No Dacono Percent of map unit:3 percent Ecological site:R067BY042CO - Clayey Plains Hydric soil rating: No Mollic halaquepts Percent of map unit:1 percent Landform:Swales Hydric soil rating: Yes Custom Soil Resource Report 16 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 17 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 18 NORTHERNENGINEERING.COM | 970.221.4158 PRELIMINARY DRAINAGE REPORT: THE CROWNE AT SUNIGA FORT COLLINS | GREELEY APPENDIX MAP POCKET DR1 – EXISTING DRAINAGE EXHIBIT DR2 – PROPOSED DRAINAGE EXHIBIT TXXXXXXXXXXXXXXXXXXXXXXXXXXXX X XX X X XXD D D D D D D D D D DFC NORTH FIELD LLC 981 LINDENMEIER ROAD EAST SUNIGA ROAD NO R T H L EM A Y A V E N U E GRAHAM JOHN C / GINGER L 1100 E VINE DRIVE 9TH STREETEX EXISTING NECCO STORM LINE A4 EX-INLET RIM = 4951.07 BOTTOM OF BOX = 4937.43 EX-STRM MH RIM = 4952.17 INV IN = 4942.96 (S) INV OUT = 4942.91 (N) EX-STRM MH RIM = 4953.11 BOTTOM OF BOX = 4942.18 EX-INLET GRATE = 4947.87 INV IN = 4942.06 (N) INV OUT = 4941.86 (S) EXISTING MANHOLE RISER A3 RIM = 4950.62 BOTTOM OF BOX = 4941.50 EX-INLET GRATE = 4947.90 INV OUT = 4941.38 (S) EX-INLET RIM = 4946.67 INV IN = 4941.87 (S) INV OUT = 4941.24 (N) EX-INLET RIM = 4946.75 INV OUT = 4941.81 (E) 125' ROW 15' SLOPE & UTILITY EASEMENT (REC. #20180037021) 15' SLOPE & UTILITY EASEMENT (REC. #20180037021) EX-INLET 30' UTILITY & DRAINAGE EASEMENT (REC. #20200000602) GREELEY WATER LINE EASEMENT (WIDTH VARIES) (REC. #20080062293) 50' DRAINAGE & UTILITY EASEMENT (REC #20190075879 & #20180037022) EXISTING NECCO BACKBONE STORM LINE A1 500-YEAR FLOODPLAIN EX-STRM MH RIM = 4951.44 INV IN = 4943.74 (N) INV OUT = 4943.54 (S) SheetCROWNE AT SUNIGAThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETof 9 DR1 DRAINAGE EXHIBITEXISTING8 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. before you dig.Call R NORTH ( IN FEET ) 0 1 INCH = 50 FEET 50 50 100 150 PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET A DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROPOSED SWALE SECTION 11 NOTES: 1.REFER TO THE PRELIMINARY DRAINAGE REPORT, DATED MARCH 15, 2023 FOR ADDITIONAL INFORMATION. A LEGEND: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION EXCLUSIVE PERMANENT ELCO WATER LINE EASEMENT (REC. #20080070035) (WIDTH VARIES) RUNOFF SUMMARY: Rational Flow Summary | Developed Basin Flow Rates BASIN TOTAL AREA (acres) Tc2 (min) Tc100 (min) C2 C100 Q2 (cfs) Q100 (cfs) EX 11.08 13.6 13.6 0.25 0.31 5.40 23.40 TUGE UGE UGE UGE D D D D D D D D D D UD UD UD UD UD UD UD UD UD UD UDMONITORING W E L L TRAFFIC RATEDTFTFTFTFTFTFDFC NORTH FIELD LLC 981 LINDENMEIER ROAD EAST SUNIGA ROAD NO R T H L EM A Y A V E N U E GRAHAM JOHN C / GINGER L 1100 E VINE DRIVE 9TH STREETA C D E F R1 R3 R4 R6 R7 R8 R10 R9 R11 G H R12 R13 R14 OS1 OS2 OS3 R2 R5 R15 OS4 a1 b1 c1 d1 e1 g1 h1 os1 os2 os3 os4 B f1 BUILDING 1000 BUILDING 2000 BUILDING 3000 BUILDING 4000 BUILDING 5000 BUILDING 6000 DOG PARK 125' ROW 15' SLOPE & UTILITY EASEMENT (REC. #20180037021) 15' SLOPE & UTILITY EASEMENT (REC. #20180037021) 30' UTILITY & DRAINAGE EASEMENT (REC. #20200000602) GREELEY WATER LINE EASEMENT (WIDTH VARIES) (REC. #20080062293) 50' DRAINAGE & UTILITY EASEMENT (REC #20190075879 & #20180037022) 30' UTILITY EASEMENT AREA INLET (TYP.) STORM DRAIN (TYP.) STORM DRAIN (TYP.) STORM DRAIN MANHOLE (TYP.) STORM DRAIN MANHOLE (TYP.) EXISTING NECCO STORM DRAIN A3 EX-INLET RIM = 4951.07 BOTTOM OF BOX = 4937.43 EX-STRM MH RIM = 4952.17 INV IN = 4942.96 (S) INV OUT = 4942.91 (N) EX-STRM MH RIM = 4953.11 BOTTOM OF BOX = 4942.18 EX-INLET GRATE = 4947.87 INV IN = 4942.06 (N) INV OUT = 4941.86 (S) EXISTING MANHOLE RISER A3 RIM = 4950.62 BOTTOM OF BOX = 4941.50 STRM MH CONNECT TO EXISTING 18" RCP INV IN = 4941.48 (W) INV OUT = 4941.28 (S) EX-INLET RIM = 4946.67 INV IN = 4941.87 (S) INV OUT = 4941.24 (N) EX-INLET RIM = 4946.75 INV OUT = 4941.81 (E) EX-INLET EXISTING NECCO BACKBONE STORM LINE A1 12'x4' RCBC @ 0.21% STORMTECH MC-7200 SYSTEM 63 ISOLATOR CHAMBERS & 441 DETENTION CHAMBERS WATER QUALITY BASIN w/ WEIR 500-YEAR FLOOPLAIN BOTTOM OF BOX = 4941.04 (S) EX-STRM MH RIM = 4951.44 INV IN = 4943.74 (N) INV OUT = 4943.54 (S) DR1 DRAINAGE EXHIBITDEVELOPED9 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. before you dig.Call R NORTH ( IN FEET ) 0 1 INCH = 50 FEET 50 50 100 150 SheetCROWNE AT SUNIGAThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETof 9 EXCLUSIVE PERMANENT ELCO WATER LINE EASEMENT (REC. #20080070035) (WIDTH VARIES) PROPOSED CONTOUR PROPOSED STORM SEWER PROPOSED SWALE EXISTING CONTOUR PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED INLET A DESIGN POINT FLOW ARROW DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY PROPOSED SWALE SECTION 11 NOTES: 1.REFER TO THE PRELIMINARY DRAINAGE REPORT, DATED MARCH 15, 2023 FOR ADDITIONAL INFORMATION. A LEGEND: FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION RUNOFF SUMMARY: LID SUMMARY: Rational Flow Summary | Developed Basin Flow Rates BASIN TOTAL AREA (acres) Tc2 (min) Tc100 (min) C2 C100 Q2 (cfs) Q100 (cfs) A 0.48 5.0 5.0 0.86 0.91 1.19 4.39 B 0.37 5.0 5.0 0.85 0.90 2.00 7.41 C 0.83 5.0 5.0 0.85 0.90 2.00 7.41 D 1.23 5.3 5.3 0.79 0.85 0.92 3.39 E 0.34 5.0 5.0 0.95 1.00 0.92 3.39 F 0.75 5.0 5.0 0.72 0.77 1.08 3.98 G 0.44 5.0 5.0 0.86 0.91 1.08 3.98 H 1.83 5.0 5.0 0.83 0.88 0.45 1.64 R1 0.16 5.0 5.0 0.95 1.00 0.45 1.64 R2 0.12 5.0 5.0 0.95 1.00 0.64 2.35 R3 0.24 5.0 5.0 0.95 1.00 0.64 2.35 R4 0.17 5.0 5.0 0.95 1.00 0.37 1.37 R5 0.14 5.0 5.0 0.95 1.00 0.37 1.37 R6 0.22 5.0 5.0 0.95 1.00 0.41 1.49 R7 0.15 5.0 5.0 0.95 1.00 0.41 1.49 R8 0.15 5.0 5.0 0.95 1.00 0.53 1.95 R9 0.20 5.0 5.0 0.95 1.00 0.53 1.95 R10 0.26 5.0 5.0 0.95 1.00 0.38 1.40 R11 0.14 5.0 5.0 0.95 1.00 0.38 1.40 R12 0.34 5.0 5.0 0.95 1.00 0.64 2.36 R13 0.24 5.0 5.0 0.95 1.00 0.64 2.36 R14 0.31 5.0 5.0 0.66 0.71 0.49 1.79 R15 0.18 5.0 5.0 0.95 1.00 0.49 1.79 OS1 0.48 9.6 9.6 0.28 0.34 0.38 1.58 OS2 0.56 12.6 12.6 0.30 0.36 0.34 1.41 OS3 0.34 10.3 10.3 0.25 0.31 0.24 1.04 OS4 0.41 12.9 12.9 0.27 0.33 0.22 0.95 Combined Basins MAJOR BASIN SC (STORMTECH, COMBINED) 9.28 5.0 5.0 0.86 0.91 22.74 84.01 MAJOR BASIN OSC (OFF-SITE, COMBINED)1.79 9.6 9.6 0.28 0.34 1.13 4.80 LID Summary Table Area (ac)% of Area Total New Impervious Area 7.88 100% Total New Impervious Area Being Treated by LID 7.72 98% Total New Impervious Area NOT being Treated by LID 0.16 2%