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HomeMy WebLinkAboutNEC LAKE AND SHIELDS - FDP190008 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTAPPENDIX A HYDROLOGIC COMPUTATIONS FINAL DRAINAGE REPORT NEC LAKE AND SHIELDS Fort Collins, Colorado June 10, 2019 Prepared for: CSURF 2537 Research Boulevard, Suite 200 Fort Collins, CO 80526 Prepared by: 301 North Howes Street, Suite 100 Fort Collins, Colorado 80521 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com Project Number: 232-047  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 absolutely necessary, we recommend double-sided printing. June 10, 2019 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Final Drainage Report for NEC Lake and Shields Dear Staff: Northern Engineering is pleased to submit this Final Drainage Report for your review. This report accompanies the Preliminary Development Review submittal for the proposed NEC Lake and Shields. This report has been prepared in accordance to the Fort Collins Stormwater Criteria Manual (FCSCM), and serves to document the stormwater impacts associated with the proposed The NEC Lake and Shields project. We understand that review by the City 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. Benjamin Ruch, PE Blaine Mathisen, EI Project Engineer Project Engineer NEC Lake and Shields Final Drainage Report TABLE OF CONTENTS I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1 A. Location ............................................................................................................................................. 1 B. Description of Property ..................................................................................................................... 2 C. Floodplain.......................................................................................................................................... 3 II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 5 A. Major Basin Description .................................................................................................................... 5 B. Sub-Basin Description ....................................................................................................................... 5 III. DRAINAGE DESIGN CRITERIA ................................................................................... 5 A. Regulations........................................................................................................................................ 5 B. Four Step Process .............................................................................................................................. 5 C. Development Criteria Reference and Constraints ............................................................................ 6 D. Hydrological Criteria ......................................................................................................................... 6 E. Hydraulic Criteria .............................................................................................................................. 7 F. Floodplain Regulations Compliance .................................................................................................. 7 G. Modifications of Criteria ................................................................................................................... 7 IV. DRAINAGE FACILITY DESIGN .................................................................................... 7 A. General Concept ............................................................................................................................... 7 B. Specific Details .................................................................................................................................. 8 V. CONCLUSIONS ...................................................................................................... 10 A. Compliance with Standards ............................................................................................................ 10 B. Drainage Concept ............................................................................................................................ 10 References ....................................................................................................................... 12 APPENDICES: APPENDIX A – Hydrologic Computations APPENDIX B – Hydraulic Computations B.1 – Storm Sewers B.2 – Inlets and Curb Cuts B.3 – Detention Facilities APPENDIX C – Water Quality Design Computations APPENDIX D – Erosion Control Report NEC Lake and Shields Final Drainage Report LIST OF TABLES AND FIGURES: Figure 1 – Aerial Photograph ................................................................................................ 2 Figure 2 – Proposed Site Plan ............................................................................................... 3 Figure 3 – Existing FEMA Floodplains .................................................................................... 4 Figure 4 – Existing City Floodplains ....................................................................................... 4 MAP POCKET: Figure 1 - Existing Drainage Exhibit Figure 2 - C7.00 - Drainage Exhibit NEC Lake and Shields Preliminary Drainage Report 1 I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map 2. NEC Lake and Shields project is located in the southwest quarter of Section 14, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. The project site is located at the northeast corner of Lake Street and Shields and expands all the way to north to James Court. Prior to this project this land use to encompass five residential homes with associated landscaping and hard surfaces. These houses have already been removed. However, even though the houses have already been removed they will be included in the rational calculations computation for the existing basins. This will be discussed in greater detail in the following sections. 4. Currently the existing lot does not have any stormwater or water quality facilities. However, there is existing stormwater infrastructure to the east of the lot associated with the Colorado State University Summit Hall Dorm parking lot. There are existing detention ponds along the south and north side of that parking lot and a rain garden along the north side of the parking lot as well. NEC Lake and Shields does not intend to use any of CSU infrastructure for storage or water quality. However, NEC Lake and Shields will be routing treated and detained flows through their systems in order for the runoff to get into the public storm sewer maintained by the City because there is NEC Lake and Shields Preliminary Drainage Report 2 no storm infrastructure in either Lake Street or Shields Street. This will be discussed in the following sections. B. Description of Property 1. NEC Lake and Shields is approximately 2.17 net acres. Figure 1 – Aerial Photograph 2. NEC Lake and Shields use to have residential homes with associated driveways and landscaping but since the purchase of the land by CSURF these structures have since been removed. These houses and associated driveways were taken into consideration when determining the existing impervious area. 3. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey, 100 percent of the site consists of Altvan- Satanta loam, which falls into Hydrologic Soil Groups B. 4. The proposed development will include the demolition of the existing drive aisle off of Lake Street, the abandonment of all water and sanitary services currently feeding into the site as well as some tree removals. The proposed project will include a single story commercial building for daycare use. There will be associated play places, sidewalks, and parking associated with this development. The current drive aisle off of Lake Street will be removed and replaced with a new drive entrance just east of where it currently is at. NEC Lake and Shields will be providing water quality in both LID and traditional methods. NEC Lake and Shields will also have two separate detention ponds that will release at reduced allowable rates. More details and discussion with regards to water quality and storage amenities can be found in the proceeding sections. NEC Lake and Shields Preliminary Drainage Report 3 Figure 2– Proposed Site Plan 5. No irrigation facilities or major drainageways are within the property limits. 6. The project site is within the High Density Mixed-Use Neighborhood District (H-M-N) Zoning District. The proposed use is permitted within the zone district. C. Floodplain 1. The subject property is not located in a FEMA or City regulatory floodplain. 2. The FEMA Panel 08069C0978G illustrates the proximity of the project site to the nearest FEMA delineated regulatory floodplain. NEC Lake and Shields Preliminary Drainage Report 4 Figure 3 – Existing FEMA Floodplains Figure 4 – Existing City Floodplains NEC Lake and Shields Preliminary Drainage Report 5 II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin Description 1. NEC Lake and Shields is located within the Old Town Basin, which is located primarily in Old Town Fort Collins. B. Sub-Basin Description 1. The property historically generally drains west to east via overland flow except for the northwest corner of the site which sheet flows north off the site into James Court. All flows generated and routed to James Court are conveyed east towards a concrete pan and curb chase at the end of the street which directs flow into the existing detention pond at the northeast corner of the existing parking lot. The project was broken down into seven separate basins. However, all the flows generated on the existing site all eventually make their way into the northeast detention pond associated with the CSU Summit Hall Dorm parking lot. The southern portion of the site is currently being conveyed into the southern detention pond. The southern detention pond then conveys flows north towards the northern pond. Therefore, all the flows are eventually routed to that northern detention pond. The proposed project will maintain these same existing flows/ See Section IV.A.4. below, for a more detailed description of the projects proposed drainage patterns. 2. No drainage is routed onto the property from the surrounding properties. A full-size copy of the Proposed Drainage Exhibit can be found in the Map Pocket at the end of this report. III. DRAINAGE DESIGN CRITERIA A. Regulations There are no optional provisions outside of the FCSCM proposed with NEC Lake and Shields project. B. Four Step Process The overall stormwater management strategy employed with NEC Lake and Shields project 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. 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 by implementing multiple Low-Impact Development (LID) strategies including: Selecting a site that has been previously developed and that use consist of five single family residences with associated hardscapes and landscaping. Providing vegetated open areas along the south, north, and east portion of the site to reduce the overall impervious area and to minimize directly connected impervious areas (MDCIA). Routing flows, to the extent feasible, through rain gardens and to increase time of concentration, promote infiltration and provide initial water quality. NEC Lake and Shields Preliminary Drainage Report 6 Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release The efforts taken in Step 1 will facilitate the reduction of runoff; however, this development will still generate stormwater runoff that will require additional BMPs and water quality. The stormwater generated from the building will be split and more than half of it will go towards the rain gardens. The runoff from the proposed parking lot and the new drive aisle off of Lake Street will be routed towards rain gardens. The water quality event will be filtered through the sand layers and discharge into the South Pond where the flows will then leave the site at a reduced existing rate. The runoff that is generated by the sidewalk along James Court and the northern half of the building will receive traditional water quality in the North Pond. However, 75% the impervious area is being treated by rain gardens. Step 3 – Stabilize Drainageways As stated in Section I.B.5, above, there are no major drainageways in or near the subject site. While this step may not seem applicable to NEC Lake and Shields, the proposed project indirectly helps achieve stabilized drainageways nonetheless. Once again, site selection has a positive effect on stream stabilization. By repurposing an already developed, under-utilized site with no existing stormwater infrastructure, combined with LID, the likelihood of bed and bank erosion is greatly reduced. Furthermore, this project will pay one-time stormwater development fees, as well as 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 and is not applicable for this project. C. Development Criteria Reference and Constraints 1. There are no known drainage studies for the existing properties. 2. The subject property is essentially an "in-fill" development project as the property is surrounded by currently developed properties. As such, several constraints have been identified during the course of this analysis that will impact the proposed drainage system including: Existing elevations all along the property line need to be maintained in order to tie into existing infrastructure. As previously mentioned, overall drainage patterns within the Master Drainage Basin will be maintained. To alleviate the current drainage problem within West Lake Street, all of the drainage will be routed north towards James Court and into the existing drainage pond at the northeast corner of the existing parking lot via storm pipes. D. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations associated with this development. Tabulated data contained in Table RA-7 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing coefficients contained in Tables RO-11 and RO-12 of the FCSCM. NEC Lake and Shields Preliminary Drainage Report 7 3. The Rational Formula-based Modified Federal Aviation Administration (FAA) procedure has been utilized for detention storage calculations. 4. Three separate design storms have been utilized to address distinct drainage scenarios. A fourth design storm has also been computed for comparison purposes. The first design storm considered is the 80th percentile rain event, which has been employed to design the project’s water quality features. The second event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third event considered is the “Major Storm,” which has a 100-year recurrence interval. The fourth storm computed, for comparison purposes only, is the 10-year event. 5. No other assumptions or calculation methods have been used with this development that are not referenced by current City of Fort Collins criteria. E. Hydraulic Criteria 1. As previously noted, the subject property historically drains towards the existing detention ponds that are along both north and south edges of the existing dorm parking lot. The majority of the site drains stormwater via overland flow. 2. All drainage facilities proposed with NEC Lake and Shields project are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District’s (UDFCD) Urban Storm Drainage Criteria Manual. 3. As stated in Section I.C.1, above, the subject property is not located within any regulatory floodplain. 4. NEC Lake and Shields project does not propose to modify any natural drainageways. F. Floodplain Regulations Compliance 1. As previously mentioned, all structures are located outside of any FEMA 100-year or City floodplain, and thus are not subject to any floodplain regulations. G. Modifications of Criteria 1. The proposed NEC Lake and Shields development is not requesting any modification at this time. IV. DRAINAGE FACILITY DESIGN A. General Concept 1. The main objectives of NEC Lake and Shields drainage design is to maintain existing drainage patterns, minimize the amount of drainage routed to West Lake Street and ensure no adverse impacts to any adjacent properties. 2. As previously mentioned, there are no off-site flows draining onto the existing property. 3. A list of tables and figures used within this report can be found in the Table of Contents at the front of the document. The tables and figures are located within the sections to which the content best applies. 4. NEC Lake and Shields project is composed of four major drainage basins, designated as Basins N1, S1, S2, and OS1. The drainage patterns for each major basin are further described below. NEC Lake and Shields Preliminary Drainage Report 8 Basin N1 Basin N1 is associated with a portion of the building, sidewalks adjacent to James Court, as well as the landscaping and play ground areas to the north of the building. Runoff generated in Basin N1 will receive standard water quality and will be released at a portion of the allowable release rate out of North Pond. Basin S1 Basin S1 is associated with the remaining portion of the building, the entire proposed parking lot, and all the landscaping to the south of the building. Runoff generated in this basin will sheet flow towards a curb and sidewalk chase which will then convey the runoff into Rain Garden 1. Rain Garden 1 was sized to adequately treat the water quality event for this basin. Once the water quality event volume is achieved the runoff will then be routed via an overflow outfall basin within Rain Garden 1 which will then convey everything above the water quality event into the South Pond. The South Pond will be releasing at a portion of the allowable release rate Basin S2 Basin S2 is exclusively associated with the new drive aisle off Lake Street. All the runoff generated in this drive aisle will be conveyed via curb and gutter into a sidewalk chase which will then convey the runoff into Rain Garden 2. Rain Garden 2 was sized to adequately treat the water quality event associated with Basin S2. Just like Basin S1, once the water quality event has been met there will be an overflow basin that will convey anything above the water quality event into the South Pond. The South Pond will be releasing at a portion of the allowable release rate. Basin OS1 Basin OS1 is associated with the area along Shields Street and James Court that was not capturable. Runoff generated in this basin will flow north along Shields Street where it will then turn the corner at James Court and flow east where it will eventually enter the site at an existing 2’ concrete pan that leads into the existing detention pond at the northeast corner of the dorm parking lot. Since Basin OS1 is leaving the site undetained the 100-year flow rate generated by this basin will be subtracted from the existing allowable release rate. Additional clarification on this reduction in allowable release rate is in the proceeding sections. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. B. Specific Details 1. The main drainage problem associated with this project site is the deficiency of water quality present within the existing site as well as grading constraints. The northern portion of the site drains overland and is captured in the North Pond. The North Pond will be releasing at a portion of the allowable release rate into the existing rain garden and detention pond adjacent to the north side of the existing parking lot. This is the historic pattern of this basin, so no adverse impacts should occur within the existing drainage ponds. The southern portion of the site drains via overland and concentrated flows and discharges directly into one of the two NEC Lake and Shields Preliminary Drainage Report 9 rain gardens. Once the rain gardens are full all excess runoff is routed towards the South Pond. The South Pond will be discharging at a portion of the allowable release rate into the existing detention pond along the southern side of the existing parking lot. Because the South Pond is releasing at a portion of the allowable release rate no adverse impacts on the existing detention pond are expected. All of the runoff generated in Basins S1 and S2 will be routed towards a rain garden for initial water quality that will promote infiltration. All of the runoff generated in Basin N1 will be routed towards the North Pond where it will receive traditional water quality. The landscape areas surrounding the project (Basin OS1) will be treated by use of a grass buffer. 2. The release rate for the undeveloped land (pre-development) was established by calculating the 2-year peak runoff rate of the existing pervious area and the 100-year peak runoff rate of the existing impervious area located within the project area, resulting in an overall release of 5.16 cfs. In excluding all portions of the proposed project that releases undetained (Basin OS1), the overall allowable peak runoff rate for the remaining site was calculated at 4.78 cfs. This remaining release rate was divided among the North Pond and South Pond associated with detention for Basins N1, S1, and S2. These release rates were utilized in the FAA method for design of the North and South ponds. (Refer to Appendix B for these calculations). 3. Detention Pond Calculations North Pond Calculations for North Pond, based on the characteristics of Basin N1, and an adjusted release rate of 1.40 cfs, indicate a detention volume of 1150 cu. ft. This volume does not include the 12-hour release WQCV calculated for this basin (261.25 cu. ft.), therefore the overall volume is 1411.25 cu. ft. The North Pond does not have any LID component therefore this is just standard water quality. The North Pond has a spill elevation of 5029.00 which is well below the building finish floor elevation (FFE) of 5035.09. The North Pond will discharge west via a storm pipe into the existing detention pond along the north side of the existing parking lot. In the case that the outfall structure gets clogged or an event greater than the 100-year event comes along the overflow path will convey the runoff northeast out of the site into James Court, where it historically has gone. South Pond Calculations for South Pond, based on the characteristics of Basins S1 and S1 and an adjusted release rate of 3.38 cfs, indicate a detention volume of 5545 cu. ft. This does not include the water quality capture volume (WQCV) associated with Basins S1 and S2. As previously mentioned Basins S1 and S2 are receiving water quality within the rain gardens. The overflow elevation of South Pond is 5028.04, therefore there is adequate difference between the FFE (5035.09) and the top water surface elevation. The South Pond will discharge west via a storm pipe into the existing detention pond along the south side of the existing parking lot. In the case that the outlet structure is clogged or excess runoff above the 100-year event is inundating the pond the excess flows will overflow at the northeast corner of the pond and follow the existing drainage pattern. NEC Lake and Shields Preliminary Drainage Report 10 4. Water Quality Results North Pond As previously mentioned Basin N1 is going to be treated via traditional extended detention water quality. Based on characteristics of Basin N1 the required water quality capture volume (WQCV) is 261.25 cu. ft. This required storage was added onto the required detention volume as mentioned previously. A water quality plate on the outlet structure will insure that the WQCV is adequately met. Rain Garden 1 Rain Garden 1 was sized based on the characteristics of Basin S1. Following Urban Drainage requirements, the required WQVC is 866.2 cu. ft. However, there was additional room to slightly increase the size of Rain Garden 1 to treat a WQCV of 915 cu. ft. Rain Garden 1 has a ponding depth of 1’ until runoff starts to enter the overflow basin. All treated runoff and excess runoff will be conveyed to the South Pond via underdrains and storm pipe where it will be detained. Rain Garden 2 Rain Garden 2 was sized based on the characteristics of Basin S2. Following Urban Drainage requirements, the required WQVC is 96.9 cu. ft. However, there was additional room to increase the size of Rain Garden 2 to treat a WQCV of 431 cu. ft. Rain Garden 2 has a ponding depth of 1’ until runoff starts to enter the overflow basin. All treated runoff and excess runoff will be conveyed to the South Pond via underdrains and storm pipe where it will be detained. Between the traditional water quality associated with the North Pond and Rain Gardens 1 and 2, NEC Lake and Shields will be treating a total of 1616 cu. ft. of runoff. This results in 347 cu. ft. of extra water quality that is not required of NEC Lake and Shields. Additionally, 80% of the impervious area associated with this project is being treated by LID methods. Refer to Appendix C for all of these calculations. V. CONCLUSIONS A. Compliance with Standards 1. The drainage design proposed with NEC Lake and Shields project complies with the City of Fort Collins’ Stormwater Criteria Manual. 2. The drainage design proposed with NEC Lake and Shields project complies with the City of Fort Collins’ Master Drainage Plan for the Old Town Basin. 3. There are no regulatory floodplains associated with NEC Lake and Shields development. 4. The drainage plan and stormwater management measures proposed with NEC Lake and Shields development are compliant with all applicable State and Federal regulations governing stormwater discharge. B. Drainage Concept 1. The drainage design proposed with this project will effectively limit potential damage associated with its stormwater runoff. NEC Lake and Shields will detain for the NEC Lake and Shields Preliminary Drainage Report 11 pervious area converted to impervious areas by releasing at the 2-year existing rate during the developed100-year storm. 2. The proposed NEC Lake and Shields development will not impact the Master Drainage Plan recommendations for the Old Town major drainage basin. NEC Lake and Shields Preliminary Drainage Report 12 References 1. City of Fort Collins Landscape Design Guidelines for Stormwater and Detention Facilities, November 5, 2009, BHA Design, Inc. with City of Fort Collins Utility Services. 2. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 3. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 4. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture. 5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: NEC Lake and Shields Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year C f = 1.00 100-year C f = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. EX-1 23625 0.54 0.00 0.01 0.00 0.00 0.53 0.17 0.17 0.21 2% EX-2 4543 0.10 0.00 0.00 0.02 0.03 0.06 0.39 0.39 0.48 27% EX-3 21995 0.50 0.00 0.00 0.10 0.09 0.31 0.38 0.38 0.47 26% EX-4 13743 0.32 0.00 0.00 0.05 0.01 0.26 0.29 0.29 0.36 16% EX-5 1822 0.04 0.00 0.00 0.01 0.00 0.02 0.48 0.48 0.60 37% EX-6 16073 0.37 0.02 0.00 0.00 0.00 0.35 0.20 0.20 0.25 6% EX-7 12649 0.29 0.05 0.00 0.06 0.00 0.19 0.43 0.43 0.54 33% Total 94450 2.17 0.07 0.02 0.24 0.13 1.71 0.29 0.29 0.36 16% Existing Impervious Overland Flow, Time of Concentration: Project: NEC Lake and Shields Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Tc Rational Method Equation: Project: NEC Lake and Shields Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: ex-1 EX-1 0.54 16 16 15 0.17 0.17 0.21 1.84 3.14 6.52 0.17 0.28 0.74 ex-2 EX-2 0.10 8 8 7 0.39 0.39 0.48 2.46 4.21 9.06 0.10 0.17 0.46 ex-3 EX-3 0.50 15 15 13 0.38 0.38 0.47 1.90 3.24 7.04 0.36 0.62 1.68 ex-4 EX-4 0.32 18 18 16 0.29 0.29 0.36 1.73 2.95 6.41 0.16 0.27 0.73 ex-5 EX-5 0.04 6 6 5 0.48 0.48 0.60 2.67 4.56 9.95 0.05 0.09 0.25 ex-6 EX-6 0.37 18 18 17 0.20 0.20 0.25 1.70 2.90 6.10 0.12 0.21 0.56 ex-7 EX-7 0.29 7 7 6 0.43 0.43 0.54 2.60 4.44 9.63 0.33 0.56 1.51 N/A Existing Impervious Area Breakdown 0.46 8 8 5 0.82 0.82 1.00 2.40 4.10 9.95 0.90 1.54 4.54 N/A Existing Pervious Area Breakdown 1.71 8 8 5 0.15 0.15 0.19 2.40 4.10 9.95 0.62 1.05 3.19 HISTORIC RUNOFF COMPUTATIONS Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Notes B. Mathisen August 21, 2018 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) C2 Total allowable release = 5.16 Flow, Q10 (cfs) Flow, Q100 (cfs) C10 CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: NEC Lake and Shields Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. N1 20008 0.46 0.00 0.17 0.07 0.00 0.22 0.56 0.56 0.70 46% S1 67339 1.55 0.37 0.19 0.17 0.00 0.81 0.53 0.53 0.67 45% S2 2906 0.07 0.07 0.00 0.00 0.00 0.00 0.95 0.95 1.00 100% OS1 4197 0.10 0.00 0.02 0.00 0.00 0.08 0.32 0.32 0.40 19% Total 94450 2.17 0.44 0.38 0.24 0.00 1.11 0.54 0.54 0.68 46% PROPOSED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Notes April 16, 2019 10-year Cf = 1.00 **Soil Classification of site is Sandy Loam** Overland Flow, Time of Concentration: Project: NEC Lake and Shields Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = T i + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S ½ Velocity (Swale Flow), V = 15·S ½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Rational Method Equation: Project: NEC Lake and Shields Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: n1 N1 0.46 6 6 5 0.56 0.56 0.70 2.67 4.56 9.95 0.69 1.17 3.20 s1 S1 1.55 10 10 8 0.53 0.53 0.67 2.26 3.86 8.59 1.86 3.17 8.83 s2 S2 0.07 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.18 0.31 0.66 os1 OS1 0.10 5 5 5 0.32 0.32 0.40 2.85 4.87 9.95 0.09 0.15 0.38 C2 Flow, Q10 (cfs) Flow, Q100 (cfs) C10 C 100 PROPOSED RUNOFF COMPUTATIONS Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Notes B. Mathisen April 16, 2019 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) Q  C f  C  i  A  Page 3 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Rational-Calcs.xlsx\DirectRunoff CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: NEC Lake and Shields Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….………………………………… 0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.40 22% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year C f = 1.00 100-year C f = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Lawns and Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. S1 and S2 70245 1.61 0.44 0.19 0.17 0.00 0.81 0.55 0.55 0.69 48% Design Point S1 18245 0.42 0.37 0.00 0.00 0.00 0.05 0.86 0.86 1.00 89% PROPOSED COMBINED/DESIGN POINT COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Notes September 26, 2018 10-year Cf = 1.00 **Soil Classification of site is Sandy Loam** Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Overland Flow, Time of Concentration: Project: NEC Lake and Shields Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = Ti + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S½ Velocity (Swale Flow), V = 15·S½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) 2-yr Tc Rational Method Equation: Project: NEC Lake and Shields Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: South Pond S1 and S2 1.61 10 10 7 0.55 0.55 0.69 2.26 3.86 8.80 2.00 3.42 9.75 s1 Design Point S1 0.42 5 5 5 0.86 0.86 1.00 2.85 4.87 9.95 1.03 1.75 4.17 PROPOSED COMBINED/DESIGN POINT RUNOFF COMPUTATIONS Intensity, i2 (in/hr) Intensity, i10 (in/hr) Intensity, i100 (in/hr) Notes B. Mathisen September 26, 2018 Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 Design Point Basin(s) Area, A (acres) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) Flow, Q2 (cfs) C2 Flow, Q10 (cfs) Flow, Q100 (cfs) C10 C100 Q = C f ( C )( i )( A ) Page 3 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Design Points Rational-Calcs.xlsx\DirectRunoff APPENDIX B HYDRAULIC COMPUTATIONS B.1 – Storm Sewers (Future Use) B.2 – Inlets (Future Use) B.3 – Detention Facilities APPENDIX B.1 STORM SEWERS (FOR FUTURE USE) Project: 232-047 Date: September 27, 2018 Calculation by: B. Mathisen Storm Line Pipe Diameter (in) Velocity (cfs) Transition Mat W x L A 15 4.54 4' x 4' B 12 3.82 4' x 4' C 12 12.06 4' x 8' D 12 3.43 4' x 4' E 12 2.83 4' x 4' Design Point Width (in) Velocity (cfs) Transition Mat W x L s1 3 3.56 8'x8' s2 2 2.06 8'x8' Scourstop Schedule CALCULATIONS FOR SCOURSTOP PROTECTION AT PIPE OUTLETS AND CURB CUTS Curb Cuts and Sidewalk Chases APPENDIX B.2 INLETS AND CURB CUTS 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 2' x 2' Curb Inlet Standard Grate Inlet Capacity Chart Low Hood Setting (4.47" Curb Setting) Mid Hood Setting (6.47" Curb Setting) High Hood Setting (8.47" Curb Setting) 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 30" Dome Grate Inlet Capacity Chart 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 Capacity (cfs) Head (ft) Nyloplast 30" Dome Grate Inlet Capacity Chart Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Sep 26 2018 Design Point S2 Rectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 1.00 Slope (%) = 0.50 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 0.66 Highlighted Depth (ft) = 0.16 Q (cfs) = 0.660 Area (sqft) = 0.32 Velocity (ft/s) = 2.06 Wetted Perim (ft) = 2.32 Crit Depth, Yc (ft) = 0.16 Top Width (ft) = 2.00 EGL (ft) = 0.23 0 .5 1 1.5 2 2.5 3 Elev (ft) Depth (ft) Section 0.75 -0.25 1.00 0.00 1.25 0.25 1.50 0.50 1.75 0.75 2.00 1.00 Reach (ft) APPENDIX B.3 DETENTION FACILITIES Pond No : n1 100-yr 0.70 5.00 min 1150 ft3 0.46 acres 0.026 ac-ft Max Release Rate = 1.40 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 961 1.00 1.40 420 541 10 7.720 1492 0.75 1.05 630 862 15 6.520 1889 0.67 0.93 840 1049 20 5.600 2164 0.63 0.88 1050 1114 25 4.980 2405 0.60 0.84 1260 1145 30 4.520 2620 0.58 0.82 1470 1150 35 4.080 2759 0.57 0.80 1680 1079 40 3.740 2890 0.56 0.79 1890 1000 45 3.460 3008 0.56 0.78 2100 908 50 3.230 3120 0.55 0.77 2310 810 55 3.030 3220 0.55 0.76 2520 700 60 2.860 3315 0.54 0.76 2730 585 65 2.720 3416 0.54 0.75 2940 476 70 2.590 3503 0.54 0.75 3150 353 75 2.480 3594 0.53 0.75 3360 234 80 2.380 3679 0.53 0.74 3570 109 85 2.290 3761 0.53 0.74 3780 -19 90 2.210 3843 0.53 0.74 3990 -147 95 2.130 3909 0.53 0.74 4200 -291 100 2.060 3980 0.53 0.74 4410 -430 105 2.000 4057 0.52 0.73 4620 -563 110 1.940 4123 0.52 0.73 4830 -707 115 1.890 4199 0.52 0.73 5040 -841 120 1.840 4266 0.52 0.73 5250 -984 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 232-047 NEC Lake and Shields Project Number : Project Name : North Pond A = Project Title Date: Project Number Calcs By: Client Pond Designation Invert Elevation Water Quality Volume 100-yr Detention Volume Total Pond Volume Min Sc D = Depth between contours (ft.) A1 = Surface Area lower contour (ft 2 ) t A2 = Surface Area upper contour (ft 2 ) Area/Row No. of Rows 5026.80 1.75 0.05 0.03 0.03 0.0000 5027.00 41.33 0.20 3.44 3.47 0.0001 5027.20 109.83 0.20 14.57 18.04 0.0004 5027.40 200.71 0.20 30.60 48.64 0.0011 5027.60 313.97 0.20 51.05 99.69 0.0023 5027.80 449.62 0.20 75.95 175.64 0.0040 5028.00 637.56 0.20 108.17 283.81 0.0065 WQCV 5028.20 798.05 0.20 143.26 427.07 0.0098 5028.40 991.24 0.20 178.58 605.65 0.0139 5028.60 1238.04 0.20 222.47 828.12 0.0190 5028.80 1418.79 0.20 265.48 1093.60 0.0251 5029.00 4603.50 0.20 571.86 1665.47 0.0382 Total Vol 5029.20 1792.17 0.20 617.87 2283.33 0.0524 Elevation Depth Volume WQCV 5027.96 1.21 0.0060 100-yr Detention 5028.81 2.06 0.0260 Overall Detention 5028.90 2.15 0.0320 Required Area Per Row Total Vol. (ac-ft) Total Vol. (ft 3 ) Incremental Vol. (ft 3 ) Incremental Depth (ft) Surface Area (ft 2 ) Total Outlet Area 0.15 sq. in. NEC Lake and Shields 4/16/2019 232-047 B. Mathisen CSURF 0.0320 ac-ft 0.0260 ac-ft North Pond Project Title Date: Project Number Calcs By: Client Pond Designation Q = 1.40 cfs C = 0.65 Q = Release Rate (cfs) Eh = 5028.94 ft C = Discharge Coefficients (unitless) Ei = 5026.75 ft Aa = Area Allowed of Opening (ft 2 ) Ec = 5026.99 ft Circular g = Gravity (32.2 ft/s 2 ) Ec = 5026.97 ft Rectangular Eh = High Water Surface Elevation (ft) Ei = Elevation of Outlet Invert (ft) 0.181363416 ft 2 Ec = Elevation of Outlet Centroid (ft) 26.116332 in 2 Orifice Size (in.) 6 in. Area (in 2 ) 26.12 sq-in Q 1.32 cfs Orifice Height (in.) 5 - 4/16 in. Orifice Width (in.) 5 in. Area (in 2 ) 26.12 sq-in Q 1.33 cfs Circular Orifice 100-Year Orifice Rectangular Orifice 100-Year Orifice NEC Lake and Sheilds April 16, 2019 232-047 B. Mathisen CSURF North Pond Aa = Pond No : s1 and s2 100-yr 0.69 5.00 min 5545 ft3 1.62 acres 0.127 ac-ft Max Release Rate = 3.38 cfs Time (min) Ft Collins 100-yr Intensity (in/hr) Inflow Volume (ft3) Outflow Adjustment Factor Qav (cfs) Outflow Volume (ft3) Storage Volume (ft3) 5 9.950 3337 1.00 3.38 1014 2323 10 7.720 5178 0.75 2.54 1521 3657 15 6.520 6559 0.67 2.25 2028 4531 20 5.600 7512 0.63 2.11 2535 4977 25 4.980 8350 0.60 2.03 3042 5308 30 4.520 9094 0.58 1.97 3549 5545 35 4.080 9577 0.57 1.93 4056 5521 40 3.740 10033 0.56 1.90 4563 5470 45 3.460 10442 0.56 1.88 5070 5372 50 3.230 10831 0.55 1.86 5577 5254 55 3.030 11177 0.55 1.84 6084 5093 60 2.860 11509 0.54 1.83 6591 4918 65 2.720 11858 0.54 1.82 7098 4760 70 2.590 12159 0.54 1.81 7605 4554 75 2.480 12475 0.53 1.80 8112 4363 80 2.380 12770 0.53 1.80 8619 4151 85 2.290 13055 0.53 1.79 9126 3929 90 2.210 13340 0.53 1.78 9633 3707 95 2.130 13571 0.53 1.78 10140 3431 100 2.060 13816 0.53 1.77 10647 3169 105 2.000 14084 0.52 1.77 11154 2930 110 1.940 14312 0.52 1.77 11661 2651 115 1.890 14577 0.52 1.76 12168 2409 120 1.840 14809 0.52 1.76 12675 2134 *Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Input Variables Results Required Detention Volume Fort Collins, Colorado 232-047 NEC Lake and Shields Project Number : Project Name : South Pond A = Project Title Date: Project Number Calcs By: Client Pond Designation Invert Elevation Water Quality Volume 100-yr Detention Volume Total Pond Volume Min Sc D = Depth between contours (ft.) A1 = Surface Area lower contour (ft 2 ) t A2 = Surface Area upper contour (ft 2 ) Area/Row No. of Rows 5024.20 5.18 0.02 0.04 0.04 0.0000 WQCV 5024.40 516.70 0.20 38.24 38.28 0.0009 5024.60 715.86 0.20 122.72 161.00 0.0037 5024.80 810.66 0.20 152.55 313.55 0.0072 5025.00 909.62 0.20 171.93 485.48 0.0111 5025.20 1012.72 0.20 192.14 677.63 0.0156 5025.40 1119.97 0.20 213.18 890.80 0.0205 5025.60 1231.37 0.20 235.05 1125.85 0.0258 5025.80 1346.92 0.20 257.74 1383.59 0.0318 5026.00 1466.61 0.20 281.27 1664.86 0.0382 5026.20 1590.46 0.20 305.62 1970.48 0.0452 5026.40 1718.45 0.20 330.81 2301.29 0.0528 5026.60 1850.59 0.20 356.82 2658.12 0.0610 5026.80 1986.88 0.20 383.67 3041.78 0.0698 5027.00 2127.31 0.20 411.34 3453.12 0.0793 5027.20 2271.90 0.20 439.84 3892.96 0.0894 5027.40 2420.69 0.20 469.18 4362.14 0.1001 5027.60 2573.51 0.20 499.34 4861.48 0.1116 5027.80 2742.73 0.20 531.53 5393.02 0.1238 5028.00 3109.58 0.20 584.85 5977.87 0.1372 Total Vol 5028.20 3703.06 0.20 680.40 6658.27 0.1529 5028.40 4275.00 0.20 797.12 7455.39 0.1712 Elevation Depth Volume WQCV 0.00 0.00 0.0000 100-yr Detention 5027.85 3.67 0.1270 Overall Detention 5027.85 3.67 0.1270 Required Area Per Row Total Vol. (ac-ft) Total Vol. (ft3) Incremental Vol. (ft3) Incremental Depth (ft) Surface Area (ft2) Total Outlet Area 0.55 sq. in. NEC Lake and Shields 9/26/2018 Project Title Date: Project Number Calcs By: Client Pond Designation Q = 3.38 cfs C = 0.65 Q = Release Rate (cfs) Eh = 5027.85 ft C = Discharge Coefficients (unitless) Ei = 5024.18 ft Aa = Area Allowed of Opening (ft2) Ec = 5024.51 ft Circular g = Gravity (32.2 ft/s2) Ec = 5024.43 ft Rectangular Eh = High Water Surface Elevation (ft) Ei = Elevation of Outlet Invert (ft) 0.338241879 ft2 Ec = Elevation of Outlet Centroid (ft) 48.706831 in2 Orifice Size (in.) 8 in. Area (in2) 48.71 sq-in Q 3.23 cfs Orifice Height (in.) 6 in. Orifice Width (in.) 8 in. Area (in2) 48.71 sq-in Q 3.26 cfs September 26, 2018 232-047 B. Mathisen CSURF South Pond Aa = Circular Orifice 100-Year Orifice Rectangular Orifice 100-Year Orifice NEC Lake and Sheilds APPENDIX C WATER QUALITY DESIGN COMPUTATIONS Project Title Date: Project Number Calcs By: Client Pond Designation 0.8 WQCV = Watershed inches of Runoff (inches) 46.00% a = Runoff Volume Reduction (constant) i = Total imperviousness Ratio (i = Iwq/100) 0.156 in A = 0.46 ac V = 0.0060 ac-ft 261.25 cu. ft. V = Water Quality Design Volume (ac-ft) WQCV = Water Quality Capture Volume (inches) A = Watershed Area (acres) Drain Time a = i = WQCV = Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event NEC Lake and Shields April 16, 2019 232-047 B. Mathisen CSURF North Pond 0.156 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 WQCV (watershed inches) Total Imperviousness Ratio (i = Iwq /100) Water Quality Capture Volume 6 hr 12 hr 24 hr 40 hr WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  WQCV  a  0.91 i 3  1 . 19 i 2  0 . 78 i  V * A 12 WQCV   Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 45.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.450 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.15 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 67,339 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 866.2 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 606 sq ft D) Actual Flat Surface Area AActual = 657 sq ft E) Area at Design Depth (Top Surface Area) ATop = 1173 sq ft F) Rain Garden Total Volume VT= 915 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = 1.5 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = 866 cu ft iii) Orifice Diameter, 3/8" Minimum DO = 5/7 in Design Procedure Form: Rain Garden (RG) Blaine Mathisen Northern Engineering September 26, 2018 NEC Lake and Shields Rain Garden 1 UD-BMP (Version 3.06, November 2016) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.06-SouthRG1.xlsm, RG 9/26/2018, 9:34 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) Blaine Mathisen Northern Engineering September 26, 2018 NEC Lake and Shields Rain Garden 1 Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.06-SouthRG1.xlsm, RG 9/26/2018, 9:34 AM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 100.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 1.000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.40 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 2,906 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 96.9 cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 58 sq ft D) Actual Flat Surface Area AActual = 232 sq ft E) Area at Design Depth (Top Surface Area) ATop = 630 sq ft F) Rain Garden Total Volume VT= 431 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y = 1.5 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 = 97 cu ft iii) Orifice Diameter, 3/8" Minimum DO = 1/4 in LESS THAN MINIMUM. USE DIAMETER OF 3/8" Design Procedure Form: Rain Garden (RG) Blaine Mathisen Northern Engineering September 26, 2018 NEC Lake and Shields Rain Garden 2 UD-BMP (Version 3.06, November 2016) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.06-SouthRG2.xlsm, RG 9/26/2018, 9:38 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) Blaine Mathisen Northern Engineering September 26, 2018 NEC Lake and Shields Rain Garden 2 Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO UD-BMP_v3.06-SouthRG2.xlsm, RG 9/26/2018, 9:38 AM Design Point Basin ID Basin Impervious Area (sq. ft.) Treatment Type LID System Area Treated by LID System (sq. ft.) Percent of Site n1 N1 10321 Standard WQ No N/A 0% s1 S1 34208 Rain Garden Yes 34208 71% s2 S2 2906 Rain Garden Yes 2906 6% OS1 600 Grass Buffer No N/A 0% Total 48035 37114 77% LID SUMMARY TABLE APPENDIX D EROSION CONTROL REPORT NEC Lake and Shields Final 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, that 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 along the disturbed perimeter, gutter protection in the adjacent roadways and inlet protection at 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 C0.01 of the Utility Plans. The Utility Plans at final design 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 will 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 StormWater 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. APPENDIX E Soils Resource Report United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Natural Area, Colorado Resources Conservation Service August 20, 2018 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 3—Altvan-Satanta loams, 0 to 3 percent slopes......................................... 13 References............................................................................................................16 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 4490900 4490920 4490940 4490960 4490980 4491000 4491020 4491040 4490900 4490920 4490940 4490960 4490980 4491000 4491020 4491040 491880 491900 491920 491940 491960 491980 492000 491880 491900 491920 491940 491960 491980 492000 40° 34' 12'' N 105° 5' 45'' W 40° 34' 12'' N 105° 5' 40'' W 40° 34' 7'' N 105° 5' 45'' W 40° 34' 7'' N 105° 5' 40'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 35 70 140 210 Feet 0 10 20 40 60 Meters Map Scale: 1:819 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 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes 2.1 100.0% Totals for Area of Interest 2.1 100.0% 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 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. Custom Soil Resource Report 11 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 3—Altvan-Satanta loams, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpw2 Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Altvan and similar soils: 45 percent Satanta and similar soils: 30 percent Minor components: 25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: Benches, terraces Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 10 inches: loam H2 - 10 to 18 inches: clay loam, loam, sandy clay loam H2 - 10 to 18 inches: loam, fine sandy loam, silt loam H2 - 10 to 18 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 18 to 30 inches: H3 - 18 to 30 inches: H3 - 18 to 30 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 13.2 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Custom Soil Resource Report 13 Hydrologic Soil Group: B Hydric soil rating: No Description of Satanta Setting Landform: Structural benches, terraces Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 18 inches: loam, clay loam, sandy clay loam H2 - 9 to 18 inches: loam, clay loam, fine sandy loam H2 - 9 to 18 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Hydric soil rating: No Minor Components Nunn Percent of map unit: 10 percent Hydric soil rating: No Larim Percent of map unit: 10 percent Hydric soil rating: No Stoneham Percent of map unit: 5 percent Hydric soil rating: No Custom Soil Resource Report 14 Custom Soil Resource Report 15 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 16 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 17 MAP POCKET HISTORIC DRAINAGE EXHIBIT PROPOSED DRAINAGE EXHIBIT EX-1 EX-3 EX-2 EX-4 EX-5 0.54 ACRES 23624.61 SQFT 0.50 ACRES 21994.80 SQFT 0.32 ACRES 13743.42 SQFT EX-6 0.37 ACRES EX-7 16073.14 SQFT 0.29 ACRES 0.04 ACRES 12649.28 SQFT 1822.38 SQFT 0.10 ACRES 4543.19 SQFT ex-1 ex-2 ex-3 ex-4 ex-5 ex-6 ex-7 VAULT ELEC TRAFFIC VAULT C S SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS X X X X X X X X X X F E S F E S F E S D X X X X X X X X X X X X S S T CABLE D S C S S S C S X X X X T C SS SS S1 S2 N1 OS1 UD UD MONITORING WELL TRAFFIC RATED MONITORING WELL TRAFFIC RATED NYLOPLAST DO NOT POLLUTE DRAINS TO WATERWAYS DO NOT POLLUTE DRAINS TO WATERWAYS NYLOPLAST DUCTILE IRON os1 n1 s1 s2 RAIN GARDEN 1 SOUTH POND NORTH POND OUTFALL RAIN GARDEN 1 OVERFLOW OUTFALL INLET OUTFALL ROOF LEADER CONNECTIONS (3) SHIELDS STREET LAKE STREET JAMES COURT RAIN GARDEN 2 RAIN GARDEN 2 OVERFLOW OUTFALL SIDEWALK CHASE EXISTING 2' PAN EXISTING CURB CHASE EXISTING OUTLET STRUCTURE FLOWLINE ELEV. = 5019.95 (ULTIMATE HISTORIC EXISTING FES DRAINAGE OUTFALL) FLOWLINE ELEV. = 5020.59 EXISTING FES FLOWLINE ELEV. = 5020.90 EXISTING FES FLOWLINE ELEV. = 5021.04 EXISTING OUTLET STRUCTURE FLOWLINE ELEV. = 5022.75 EXISTING CHASE EXISTING PAN EXISTING PAN EXISTING CHASE EXISTING CHASE 12" RCP 18" RCP EXISTING NORTH DETENTION POND (REFERENCES MADE TO THIS IN DRAINAGE REPORT) EXISTING SOUTH DETENTION POND (REFERENCES MADE TO THIS IN DRAINAGE REPORT) EMERGENCY OVERFLOW PATH EMERGENCY OVERFLOW PATH SCOURSTOP (TYP.) LOT 1 LOT 2 INLET INLET INLET INLET INLET Sheet NEC LAKE & SHIELDS These drawings are instruments of service provided by Northern Engineering Services, Inc. and are not to be used for any type of construction unless signed and sealed by a Professional Engineer in the employ of Northern Engineering Services, Inc. NOT FOR CONSTRUCTION REVIEW SET E NGINEER ING N O R T H E RN FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.com of 16 C7.00 DRAINAGE EXHIBIT 17 NORTH ( IN FEET ) 0 1 INCH = 30 FEET 30 30 60 90 City Engineer Date Date Date Date Date Stormwater Utility Parks & Recreation Traffic Engineer Date Water & Wastewater Utility City of Fort Collins, Colorado UTILITY PLAN APPROVAL Environmental Planner CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R LEGEND: PROPOSED STORM SEWER PROPOSED CURB & GUTTER PROPERTY BOUNDARY PROPOSED STORM INLET EXISTING CURB & GUTTER PROPOSED OVERLAND FLOW EXISTING MAJOR CONTOUR PROPOSED MAJOR CONTOUR LID SUMMARY: A2 a3 DRAINAGE BASIN AREA DRAINAGE BASIN ID DRAINAGE BASIN MINOR/MAJOR COEFF. EXISTING STORM SEWER ST PROPOSED DIRECT FLOW BASIN DELINEATION 1. REFER TO "FINAL DRAINAGE REPORT FOR NEC LAKE & SHIELDS, DATED JUNE 11, 2019" PREPARED BY NORTHERN ENGINEERING ON 06.11.2019 FOR ADDITIONAL INFORMATION. NOTES: BASIN ID TOTAL AREA (acres) C2 C100 Q2 (cfs) Q100 (cfs) N1 0.459 0.56 0.70 0.69 3.20 S1 1.546 0.53 0.67 1.86 8.83 S2 0.067 0.95 1.00 0.18 0.66 OS1 0.096 0.32 0.40 0.09 0.38 RUNOFF SUMMARY: Design Point Basin ID Basin Impervio us Area (sq. ft.) Treatment Type LID System Area Treated by LID System (sq. ft.) Percent of Site Treated by LID System n1 N1 10454 Standard WQ No N/A 0% s1 S1 32166 Rain Garden Yes 34208 74% s2 S2 2906 Rain Garden Yes 2906 6% OS1 871 Grass Buffer No N/A 0% Total 46397 37114 80% 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 12, Oct 10, 2017 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Mar 20, 2015—Oct 15, 2016 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      12 hr 232-047 B. Mathisen CSURF 0.1270 ac-ft 0.1270 ac-ft South Pond 0.05 11 0.0000 ac-ft 5024.18 ft South Pond Volume Elevation (ft) n 1/4 0.008 sq-in Circular Perforation Sizing Dia (in.) 1 Calc. Depths ( ) 3 * * 1 2 1 2 D A A A A V = + + Tc = Project Location : Design Point C = Design Storm Page 1 of 1 232-047_SouthPondDetentionVolume_FAAModified Method.xls 0.05 3 0.0060 ac-ft 5026.75 ft North Pond Volume Elevation (ft) n 1/4 0.024 sq-in Circular Perforation Sizing Dia (in.) 1 Calc. Depths   3 D * A 1 A 2 A 1 * A 2 V    Tc = Project Location : Design Point C = Design Storm Page 1 of 1 232-047_NorthPondDetentionVolume_FAAModified Method.xls (min) 10-yr Tc (min) 100-yr Tc (min) South Pond S1 and S2 No 0.55 0.55 0.69 150 2.25% 9.6 9.6 7.2 0 N/A N/A N/A 0 N/A N/A N/A 10 10 7 s1 Design Point S1 No 0.86 0.86 1.00 150 2.00% 4.4 4.4 1.8 0 N/A N/A N/A 0 N/A N/A N/A 5 5 5 PROPOSED COMBINED/DESIGN POINT TIME OF CONCENTRATION COMPUTATIONS B. Mathisen Design Point Basin Overland Flow Gutter Flow Swale Flow Time of Concentration September 26, 2018 (Equation RO-4) ( ) 3 1 1 . 87 1 . 1 * S C Cf L Ti = − Page 2 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Design Points Rational-Calcs.xlsx\Tc-2-yr_&_100-yr Page 1 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Design Points Rational-Calcs.xlsx\Proposed C-Values Tt (min) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) n1 N1 No 0.56 0.56 0.70 100 4.50% 6.1 6.1 4.5 0 N/A N/A N/A 0 N/A N/A N/A 6 6 5 s1 S1 No 0.53 0.53 0.67 150 2.25% 9.9 9.9 7.6 0 N/A N/A N/A 0 N/A N/A N/A 10 10 8 s2 S2 No 0.95 0.95 1.00 150 2.00% 2.7 2.7 1.8 0 N/A N/A N/A 0 N/A N/A N/A 5 5 5 os1 OS1 No 0.32 0.32 0.40 75 17.00% 4.9 4.9 4.4 0 N/A N/A N/A 0 N/A N/A N/A 5 5 5 PROPOSED TIME OF CONCENTRATION COMPUTATIONS B. Mathisen Design Point Basin Overland Flow Gutter Flow Swale Flow Time of Concentration April 16, 2019 (Equation RO-4)   3 1 1 . 87 1 . 1 * S C Cf L Ti   Page 2 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Rational-Calcs.xlsx\Tc-2-yr_&_100-yr Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Page 1 of 21 D:\Projects\232-047\Drainage\Hydrology\232-047_Proposed Rational-Calcs.xlsx\Proposed C-Values C100 Q = C f ( C )( i )( A ) Page 3 of 20 D:\Projects\232-047\Drainage\Hydrology\232-047_Existing Rational-Calcs.xlsx\Hist-Direct-Runoff (min) 10-yr Tc (min) 100-yr Tc (min) ex-1 EX-1 No 0.17 0.17 0.21 181 3.31% 15.8 15.8 15.0 0 N/A N/A N/A 0 N/A N/A N/A 16 16 15 ex-2 EX-2 No 0.39 0.39 0.48 85 3.88% 7.8 7.8 6.8 0 N/A N/A N/A 0 N/A N/A N/A 8 8 7 ex-3 EX-3 No 0.38 0.38 0.47 196 2.04% 14.9 14.9 12.9 0 N/A N/A N/A 0 N/A N/A N/A 15 15 13 ex-4 EX-4 No 0.29 0.29 0.36 218 2.06% 17.6 17.6 16.0 0 N/A N/A N/A 0 N/A N/A N/A 18 18 16 ex-5 EX-5 No 0.48 0.48 0.60 63 3.17% 6.3 6.3 5.1 0 N/A N/A N/A 0 N/A N/A N/A 6 6 5 ex-6 EX-6 No 0.20 0.20 0.25 170 1.76% 18.2 18.2 17.2 0 N/A N/A N/A 0 N/A N/A N/A 18 18 17 ex-7 EX-7 No 0.43 0.43 0.54 77 3.90% 7.0 7.0 5.8 0 N/A N/A N/A 0 N/A N/A N/A 7 7 6 N/A Existing Impervious Area Breakdown No 0.82 0.82 1.00 181 3.31% 4.7 4.7 1.7 0 N/A N/A N/A 0 N/A N/A N/A 5 5 5 N/A Existing Pervious Area Breakdown No 0.15 0.15 0.19 22 4.23% 5.2 5.2 4.9 0 N/A N/A N/A 0 N/A N/A N/A 5 5 5 HISTORIC TIME OF CONCENTRATION COMPUTATIONS B. Mathisen Design Point Basin Overland Flow Gutter Flow Swale Flow Time of Concentration August 21, 2018 (Equation RO-4) ( ) 3 1 1 . 87 1 . 1 * S C Cf L Ti = − Page 2 of 20 D:\Projects\232-047\Drainage\Hydrology\232-047_Existing Rational-Calcs.xlsx\Hist-Tc-10-yr_&_100-yr Area Breakdown 19883 0.46 0.07 0.02 0.24 0.13 0.00 0.82 0.82 1.00 77% Existing Pervious Area Breakdown 74567 1.71 0.00 0.00 0.00 0.00 1.71 0.15 0.15 0.19 0% HISTORIC COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Notes August 21, 2018 10-year Cf = 1.00 **Soil Classification of site is Sandy Loam** Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I. Existing Impervious Area Breakdown Page 1 of 20 D:\Projects\232-047\Drainage\Hydrology\232-047_Existing Rational-Calcs.xlsx\Hist-C-Values