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HomeMy WebLinkAboutFOOTHILLS UNITARIAN CHURCH EXPANSION - FDP210027 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORT         PREPARED FOR: FOOTHILLS UNITARIAN CHURCH 1815 YORKTOIWN AVENUE, SECTION 22, TOWNSHIP 7 NORTH, RANGE 69 WEST OF THE 6th PRINCIPAL MERIDIAN LARIMER COUNTY, COLORADO         FINAL DRAINAGE & EROSION CONTROL REPORT           PREPARED BY: BASELINE ENGINEERING CORPORATION 112 N. Rubey Drive, #210 GOLDEN, CO 80401 January 7, 2022 JOB # CO3355 2    ENGINEER CERTIFICATION “This report (plan) for the Final Drainage and Erosion Control Report for the “Foothills Unitarian Church,” was prepared by me (or under my direct supervision) in accordance with the provisions of the Fort Collins Stormwater Criteria Manual and was designed to comply with the provisions thereof. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others.”       _______________________________________________ Noah J. Nemmers Registered Professional Engineer State of Colorado No. 39820       OWNER CERTIFICATION “(Owner/Applicant) hereby certifies that the drainage facilities for the “Foothills Unitarian Church,” will be constructed according to the design presented in this report. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed or reviewed by my engineer. I also understand that the City of Fort Collins relies on the representations of others to establish that drainage facilities are designed and built-in compliance with applicable guidelines, standards or specifications. Review by the City of Fort Collins can therefore in no way limit or diminish any liability which I or any other party may have with respect to the design or construction of such facilities.”     (Owner/Applicant) By: ____________________________________ Date: 3     Table of Contents    I.  General Location and Description......................................................................................................... 4  A.  Location ............................................................................................................................................. 4  B.  Description of Property ..................................................................................................................... 4  II.  Drainage Basin and Sub‐Basins ............................................................................................................. 5  A.  Major Basin Description .................................................................................................................... 5  B.  Sub‐Basin Description ....................................................................................................................... 5  III.  Drainage Design Criteria ................................................................................................................... 6  A.  Regulations ........................................................................................................................................ 6  B.  Hydrological Criteria ......................................................................................................................... 6  C.  Hydraulic Criteria .............................................................................................................................. 7  D.  Waivers from Criteria ........................................................................................................................ 7  IV.  Drainage Facility Design .................................................................................................................... 8  A.  General Concepts .............................................................................................................................. 8  B.  Specific Details .................................................................................................................................. 8  C.  Stormwater Storage Facility .............................................................................................................. 9  V.  Erosion and Sediment Control ............................................................................................................ 10  VI.  Conclusions ..................................................................................................................................... 13  A.  Compliance with Standards ............................................................................................................ 13  B.  Drainage Concept ............................................................................................................................ 14  VII.  References ...................................................................................................................................... 14  VIII.  APPENDIX ........................................................................................................................................ 15  VICINTIY, FIRM & SOILS MAP  HYDROLOGICAL COMPUTATIONS  HYDRAULIC COMPUTATIONS    CURB HYDROLOGICAL COMPUTATIONS  DRAINAGE DETAILS & PLANS         4    I. General Location and Description  A. Location  1. Township, Range, Section, ¼ Section:  The subject property is located in Section  22, Township 7 North, Range 69 West of the 6th Principal Meridian, Larimer  County, State of Colorado.     2. Local streets within and adjacent to the development with ROW width shown:   The parcel is bordered by W. Drake Road to the south, Yorktown Drive to the  west, Yorktown Avenue to the north and Constitution Avenue to the east, see  Appendix A for Vicinity Map.    3. Major drainageways, facilities and easements within and adjacent to the site:   The  site  lies  in  the  Spring  Creek  Drainage  basin  and  crosses  Drake  Road  approximately 800 feet East of the Foothills Unitarian Church expansion (Site).      4. Names of surrounding developments:  The existing church is located within a  residential area.  There are existing single‐family residences located to the north,  west and east.  The Georgetown Townhouse/Condos are located to the south.    B. Description of Property   1. Area in Acres:     Property Area =   3.02 Acres         Tributary Pond Limits =  0.88 Acres     2. Ground cover:  Ground cover on site currently consists of mature landscaping  which includes trees and shrubs along with established lawns.    3. National Resources Conversation Service (NRCS) soils classification:  According  to the Natural Resources Conservation Service (NRCS) Soils Survey in Appendix A,  the project area is comprised mostly of soils in Hydrologic Soil Group B, which  consists of Altvan‐Satanta loam complex soil.     4. Major Drainageways:  The Site lies within the Spring Creek Drainage Basin in the  reach  East  of  Taft  Hill  Road  as  identified  by  the  Spring  Creek Drainageway  Planning Study.    5. Floodplain:  According to the Flood Insurance Rate Map Panel No. 08069C0986G  dated 5/2/2012, the site is located with Zone X, an area of minimal flood hazard  (see Appendix)     6. General Project Description:  The proposed Foothills Unitarian Church expansion  includes a new two‐story addition at the southwest edge of the existing building.   There will also be new pedestrian connection to the existing parking lot located  on the west, and to the existing sidewalk along Drake.  In addition to the proposed  expansion; there will also be ROW improvements along Yorktown Drive and  Yorktown Avenue which consists of new curb, gutter and sidewalk.      7. Irrigation facilities:  There are no known irrigation facilities within 200 feet of the  5    site.      8. Proposed Land Use:  Place of worship  II. Drainage Basin and Sub‐Basins  A. Major Basin Description  1. On‐site and off‐site major drainage basin characteristic and flow patterns and  path:  Historically the site drains into the surrounding road ROW and is tributary  to Drake Road.      2. Existing  and  proposed  land  uses  within  the  basins  if  known:    The  existing  Foothills Unitarian Church will remain as a place of worship.    3. Discussion of all drainageway planning or floodplain delineation studies that  affect the major drainageways, such as FHAD Studies and Outfall System  Planning  studies:    There  are  no  known  drainageway  planning  or  floodplain  delineation studies associated with the property.        4. Discussion  of  the  condition  of  any  channel  within  or  adjacent  to  the  development, including existing conditions, need for improvements can impact  on the proposed development:  Spring Creek is directly east of the proposed  development.      5. Discussion of the impacts of the off‐site flow patterns and paths, under fully  developed conditions:  Currently flow from off‐site are captured with curb and  gutter and conveyed into the existing public storm sewer system within Drake  Road.      6. Identification of all irrigation facilities within the basin which will influence or  be influenced by the local drainage:  There are no known irrigation facilities  within  the  basin  which  will  influence  or  be  influenced  with  the  developed  drainage patterns.  B. Sub‐Basin Description  1. On‐site  and  off‐site  minor  drainage  basin  characteristics  and  flow  patterns  under historic and developed conditions:  Based on the Final Drainage Study &  Erosion Control Report – Foothills Unitarian Church Expansion dated April 3,  1996;  the  property  contains  4  basins  (A1–A4).    The  proposed  expansion  completely  encompasses  basin  A3.    Historic  Basin  A3  flows  are  currently  conveyed via surface flow into Drake Road and will outfall into the public storm  sewer system in the existing inlet directly south of the proposed expansion area.       Basin A1 flows will remain unchanged with the proposed ROW improvements  along  Yorktown  Avenue,  and  outfall  into  the  existing  curb  and  gutter  as  it  currently does today.  Basin A2 flow patterns will mimic historic and continue into  Drake Road.  Basin A4 flow patterns will also remain unchanged and be captured  6    within the western parking lot detention area prior to outfalling into Drake Road  and ultimately Spring Creek via the public storm sewer system, see Appendix for  drainage map.    With  the  proposed  building  expansion,  developed  basin P1  will  analyze  the  historic basin A3 to determine the required detention volumes based on the  added imperviousness to the site.    Basin P1 is approximately 0.88 acres with an imperviousness of 39%.  This basin  consists of the area contained within historic Basin A3 and also includes additional  pervious  areas  that  include  the  proposed  detention  pond.    The  2‐yr  runoff  coefficient is 0.48 and the 100‐yr runoff coefficient is 0.60.      2. Existing and proposed land uses within the basins:  The site currently is a place  of worship with mature landscaping and associated parking and walkways.  The  proposed development will consist of a building expansion, and the primary use  will remain the same.    3. Discussion of irrigation facilities that will influence or impacted by the site  drainage:  There are no known existing irrigation facilities that will be impacted  by the proposed development.     4. Discussion of the impacts of the off‐site flow patterns and paths under fully  developed conditions:  Under the fully developed conditions flows from within  the surrounding roadways will be captured with curb and gutter and ultimately  into Drake Road.      III. Drainage Design Criteria  A. Regulations  1. Discussion of the optional provisions selected or the deviation from the Criteria,  if any, and its justification:  Calculation methods used follow the provisions set  forth in the Fort Collins Stormwater Criteria Manual.  B. Hydrological Criteria   1. Identify design rainfall:  Storm incremental precipitation determined by using IDF  Table 3.4‐1 from the Fort Collins Stormwater Criteria Manual.     2. Identify runoff calculation method:  The Rational Method was used to determine  developed  flow  volumes  for  historic  and  developed  conditions.  The  Rational  Formula is Q = CiA, where Q, the maximum rate of runoff is equal to the runoff  coefficient C, times the rainfall intensity (I), times the area (A).      3. Identify detention discharge and storage calculation method:  Water quality is  to be provided by a proposed rain garden. Stormwater detention in excess of the  WQCV and up to the 100‐yr storm is proposed to be provided within a newly  7    proposed detention  pond. The proposed  pond was evaluated using the  FAA  method and designed to hold the required 100‐yr storage volume excluding the  WQCV for the project, which is captured by the rain garden. The  required volume  is based on the additional impervious area. The existing impervious areas have  been “grandfathered” in and this runoff can be passed through the pond.  The  required WQCV is 541 cubic feet. The total required 100‐yr detention volume is  1379 cubic feet which includes the required WQCV.      4. Identify design storm recurrence intervals:  Design storm recurrence intervals of  2 and 100‐year events were examined in this study    5. Discussion and justification or other criteria or calculation method used that are  not presented in or referenced by these the CRITERIA:  All criteria and calculation  methods used are presented in or referenced by the Fort Collins Stormwater  Criteria Manual.   The allowable release rate and required volume for a minor redevelopment of an  existing site that has no detention, will be based on the following;  a) Calculation for allowable release rate  a. 100‐yr flows from existing impervious areas are grandfathered.  b. New impervious are require flows to be detained to the 2‐yr historic  flow rate.  c. Calculate the 100‐yr flow rate from all existing impervious areas onsite.  d. Calculate the 100‐yr flow rate for pervious areas that will remain as  pervious.    e. Calculate  the  2‐yr  release  rate,  for  pervious  areas  to  convert to  impervious.  Assuming C‐factor = 0.15 for 0% impervious (historic).  f. Sum the flow rates calculated.  This will be the max allowable release  rate for site.   b) Calculation for detention.  a. Calculate  the  free  releases  from  site  (100yr).   Subtract  from  max  allowable release.  This will be the maximum allowable release rate.  b. Perform  FAA  detention  calculation  using  the  "required  detention  release  rate" which  will  determine  the  required  detention  volume,  based on the mass balance method.   c. Use area and C factor for everything draining to the pond location.  C. Hydraulic Criteria   1. Identify various capacity references:  The Fort Collins Stormwater Criteria  Manual were utilized in the storm drainage design for the proposed  development.  See Appendix C for hydraulics calculations of the storm sewer  system for sizing details.     D. Waivers from Criteria  1. Provide justification for each waiver:  No waivers are requested for the proposed  development.  8    IV. Drainage Facility Design   A. General Concepts  1. Discussion of concept and typical drainage patterns: The proposed Foothills  Unitarian Church expansion includes an addition at the southwest edge of the  existing  building.    There  are  no  known  drainage  issues  on  the  site  with  the  proposed expansion.  Historically the drainage flows for the di sturbed area based  on basin A3 flows across the property in West Drake Road right of way.    The pre‐development flows for the site are approximately 0.69 CFS for the minor  event and 2.94 CFS for the major event.  In the developed condition flows mimic  the historic flow patterns into the proposed water quality rain garden and 100‐yr  detention pond at the southeast portion of the site.  The rain garden and pond  will be fitted with 100‐yr orifice plates in order to have flows released at the  allowable rate.     Post‐development flows were determined to be 0.87 CFS and 3.79 CFS for the  minor and major event.   All drainage that occurs within the disturbance limits of basin P1 will be directed  into the rain garden by overland flow. Once in the rain garden, water will infiltrate  into the ground and be collected by the underdrain system. For storm events  where the accumulated volume exceeds the WQCV, a spillway will direct water  into the detention pond. In the detention pond, water will be conveyed through  the outlet structure at the allowable release rate, while an emergency spillway  accounts for events greater than the 1‐hour, 100‐yr storm.    2. Discussion of anticipated and proposed drainage patterns.  Discuss how runoff  is conveyed off‐site to nearest adequate drainage facility.  Discuss flow path and  downstream capacity:  The flows from the proposed expansion will be conveyed  overland to the rain garden. Water that remains in the rain garden will drain  through the filtration media to the underdrain system and will be released into  the onsite storm system. Any volumes exceeding the WQCV will overflow into a  proposed detention pond.  The outlet structure of the pond includes a 12‐inch  reinforced  concrete  pipe  with  a  restrictor  plate  that  feeds  into  the  onsite  stormwater system. The emergency spillway will include a riprap lined cutoff wall.   A 12‐inch outlet pipe will tie the onsite storm system into an existing storm inlet  within West Drake Road right of way.  B. Specific Details  1. Discussion of drainage problems encountered and solutions at specific design  points:  There are no known drainage problems encountered and any design  points for the proposed development.     2. Discussion of detention storage and outlet design:  The pond is designed per the  mass  balance  method  in  order  to  determine  the  required  detention  for  developments adding over 1000 sf of impervious areas.  The pond outlets is fitted  with a restrictor plate. Flows from the two detention areas meet at a manhole  onsite that connects to a pipe to the back of an existing storm inlet within West  Drake Road right of way.      9    C. Stormwater Storage Facility  1. Discuss detention pond designs, including release rates, storage volumes and  water surface elevations for the WQCV and emergency overflow conditions,  outlet structure design, emergency spillway design, etc:  The proposed storm  drainage design for the expansion consists of a rain garden and detention pond.  The following table highlights the important design parameters of the storm  water storage facilities.     Stormwater Detention Facilities Design Parameters  Total Property Area 3.02 Acres  Tributary Area of Detention 0.88 Acres  Existing Imperviousness of Tributary 28%  Proposed Imperviousness of Tributary 39%  Change in Imperviousness +11%  Allowable 100 Year Release Rate 2.81 CFS  Volume of 100 Year Storm Event 1379 Cubic Feet  WQCV 541 Cubic Feet    Rain Garden Facility Design Parameters  Detention Volume (WQCV) 541 Cubic Feet  WSEL WQCV 5066.95’  Bottom of Pond 5066.36’  Spillway Elevation 5066.95’  Top of Pond 5067.50’  Freeboard 0.55’    Detention Pond Facility Design Parameters  Detention Volume (100yr‐WQCV) 1379 Cubic Feet  WSEL 100yr 5066.85’  Bottom of Pond 5065.25’  Spillway Elevation 5066.85’  Top of Pond 5067.50’  Freeboard 0.65’  Please refer to the appendix for the detailed design for the rain garden and  detention pond.    There will no off‐site flows that will not be detained in the detention pond,  therefore there will be no reduction in the allowable release rate.  The location  of the pond is ideal for events greater than the 100‐year event due to its close  proximity to the existing storm inlet within West Drake Road.     2. Discuss  pond  outfall  locations  and  design,  including  method  of energy  dissipation:  The pond outfall is located at the south end property where it ties  into the back of an existing inlet within West Drake Road right of way.  A 7‐foot  emergency spillway line which incorporates a 23‐foot headwall with soiled rip rap  are to be part of the spillway design.      10    3. Discuss how runoff is conveyed from all pond outfalls and emergency spillways  to the nearest major drainageway, including a discussion of the flow path and  capacity downstream of the outfall to the nearest major drainageway:  Runoff  from the proposed expansion will be conveyed into an existing storm inlet within  West Drake Road right of way, where it ultimately outfalls into Spring Creek,  directly east of the site.  Based on the current historic flows and the allowable  release rate into the creek, there is no negative impacts of the flows from the  development into the creek.  V. Erosion and Sediment Control  A. Construction Activities:    1. Total Area of Disturbance:  27,400 sf (0.63 acres)  2. Total areas of staging and storage:  A 830 sf stabilized staging area and a ~100 cy  stockpile for material has been provided as a part of the project. See erosion  control plan for locations.     3. Total volume of imported and exported material:  Earthwork onsite is expected  to be balanced, with less than 100 cy of material needed to be imported/exported  for completion.   4. General: The construction activities described in this document will have no  impact on wetlands, streams or threatened species on the parent or adjacent  properties. No additional State or Federal permits will be required in order to  complete the proposed construction.   B. Potential Pollutant Sources  1. Disturbed and stored soils: Soils exposed by grading activities as well as those that  are temporarily stockpiled on site have the potential to contribute to runoff of  sediment when storm events occur prior to final stabilization. Silt fence shall be  installed along the downslope side of all grading activities and stockpile locations to  limit the sediment that is transported offsite. Additionally, the existing adjacent  roadway inlets and the proposed drainage facility inlets will be protected to prevent  sediment from being introduced to the local stormwater system.   2. Vehicle tracking of sediments: Vehicles that encounter exposed soils onsite have  the potential to transport those soils offsite. Once offsite, the sediment can be  introduced to the local storm system during storm events. A manufactured vehicle  tracking control mat will be used at the construction entrance/exit to the site to  remove sediment on vehicles as they leave the site. The stabilized staging area (SSA)  and route between the construction entrance and the SSA will be free of loose soil,  which will limit the amount of sediment that builds up on construction vehicles. Any  track‐out that occurs shall be scraped and swept.   3. Management of contaminated soils: There is no expectation of encountering  contaminated soils onsite.   4. Loading and unloading operations: Loading and unloading of construction materials  and equipment shall be done only in stabilized areas via the VTC access. Care shall  be taken to only expose equipment that is directly related to grading operations to  loose soils and that all equipment is cleaned before leaving the site.   11    5. Outdoor storage of construction materials: Construction materials shall be stored  in stabilized areas, and frequently inspected to ensure that storage is sufficient to  avoid unwanted runoff of weathered material. Chemicals and easily weathered  materials will not be stored onsite when not in use, unless properly contained in a  dry location. Spill kits shall be readily accessible in locations where chemical  materials are stored.   6. Bulk storage of materials: Due to the scope of the project, bulk storage of materials  beyond those described above is not expected for this site.   7. Vehicle and equipment maintenance and fueling: Low amounts of onsite fueling  and maintenance are anticipated, due to the scope of the project. In the case where  onsite fueling and maintenance is done, activities will be done as far away from  stormwater features as possible on a stabilized area and done with spill kits on  hand.   8. Significant dust or particulate generating processes: Grading activities are potential  sources of atmospheric pollution, and therefore reasonable precautions must be  made to limit dust generation. This includes slowing site speeds on loose soil as well  as watering loose soils if necessary.   9. Routine maintenance activities involving fertilizers, pesticides, detergents, fuels,  etc.: Fertilizers and pesticides will be utilized during the final stabilization of the site,  and it is expected to have various solvents and petroleum products onsite during  the construction of the addition to the building. These items will be stored in dry  areas in order to minimize their potential exposure to runoff. Inspection of storage  areas will be required regularly. During application, proper application rates and  timing will ensure that runoff is limited. Any bodies of water exhibiting rainbow  sheen, sudsy or discoloration that are observed shall be inspected to determine  source and cleaned appropriately.   10.  On‐site waste management practices: Waste generated from activities on site will  be neat piles, or within a job dumpster when applicable. The dumpster and other  wastes shall be removed from the site on intervals as needed to provide a clean,  neat working area. Waste piles and dumpsters shall be stored at least 50 ft away  from drainage features.   11. Concrete truck/equipment washing: Concrete work will be performed during the  project, with material being provided by premixed concrete trucks. Cleaning  operations of the chute and pumps will be performed withing the dedicated  concrete washout area (CWA). The CWA shall be constructed as detailed in the  plans, with the intent that it provides a singular location for concrete waste to  accumulate so that it will not infiltrate into the soil, or become tracked by the  equipment to other locations within the job site.   12. Dedicated asphalt and concrete batch plants: No dedicated plants will be onsite. All  asphalt and concrete will come from offsite plants that have their own CDPS permit  coverage.  13. Non‐industrial waste sources such as worker trash and portable toilets: Worker  trash will be managed with access to trash cans which shall be emptied into the  dumpster as needed. Sanitary facilities on site shall be cleaned regularly and  securely fastened at least 50 feet away from drainage facilities when installed.   14. Saw cutting and grinding: Saw cutting is planned as a part of the improvements to  the sidewalks. The dust generated as a result of cutting operations will need to be  controlled by using water on the saw blade. The slurry that is produced as a result  12    will need to be vacuumed, or allowed to dry and swept and scraped from the  remaining surface.  15. Other non‐stormwater discharges: No dewatering is anticipated to be required due  to the depth of cut and water table elevation.  16. Other: None.  C. Construction Control Measures:  1. VTC: Vehicle Tracking Control Pads are to be used at the exit of the site to control  sediments being tracked offsite by vehicles. Due to the existing nature of the  construction area (an asphalt parking lot), a typical aggregate VTC cannot be used. A  high‐strength HDPE manufactured pad will be used in lieu. See erosion control plan  for location of VTC.   2. RS: Rock socks will be placed along the existing curb and gutter around the site to  slow runoff flows so that sediment can settle and collect. See erosion control plan  for location of rock socks.   3. SF: Silt fence shall be installed along the south side of the property, which is down  slope of the proposed grading and construction. See erosion control plan for  locations and quantities of silt fence.    4. IP: Inlet protection will be initially placed at the two storm sewer inlets on West  Drake Road to stop sediment from being introduced to the storm sewer system.  When the inlet for the detention pond is constructed, this inlet will be protected as  well.   5. CWA: The concrete washout area shall be the only location that concrete trucks and  equipment is washed out. See erosion control plan for location and details.   6. SP: Topsoil and cut material from grading shall be stored in the stockpile area on a  temporary basis. See erosion control plan for location and details.  7. SSA: The stabilized staging area onsite is the area where materials and equipment  shall be stored when not in use. See erosion control plan for location and details.  8. CD: Check dams are to be placed within the proposed swales to slow down flows.  See erosion control plan for location and details.  9. SM: Seeding and mulching to be used for permanent stabilization. Seed mixes for  the disturbed areas and rain garden can be found in the landscaping plan for the  site.  10. ECB: Erosion control blankets to be used in high slope areas around the rain garden  and detention pond to limit erosion and provide a stable surface for permanent  seeding.    D. Installation and Removal Sequence of Control Measures  The sequencing of control measures are as follows:  Initial – Prior to any earth disturbing work commencing: VTC, RS, SF, IP  Interim – To be established at the earliest reasonable point in the construction of the  site. IE: Inlet protection for the drainage pond shall be placed after construction of the  inlet is completed: IP, CWA, SP, SSA, CD  Final – Construction BMPs to remain after the completion of the project: PS, ECB  13    E. Maintenance and Inspection Requirements  All BMPs to be regularly inspected to ensure that they are functioning properly and are  undamaged. In addition to regular inspection, BMPs are to be inspected after each rain  event. See the erosion control details for specific maintenance requirements for  individual BMPs.   F. Final Vegetation and Stabilization  Final vegetation for the site will consist of two main zones. The rain garden, and the rest  of the exposed soil. Both areas will be stabilized with seeding at the completion of site  grading. See the landscape plans for details on the seed mix, planting methods and  schedule.   G. Permanent BMPs:    1. General:  The City of Fort Collins requires a four‐step process for receiving  water protection that focuses on reducing runoff volumes, treating WQCV,  stabilizing streams and implementing long‐term source controls. The Four Step  Process pertains to management of smaller, frequently occurring events, as  opposed to larger storms for which drainage and flood control infrastructure  are sized. Implementation of these four steps helps to achieve compliance with  stormwater permit requirements (i.e. City’s MS4 permit). Added benefits of  implementing  the  complete  process  can  include  improved  site  aesthetics  through functional landscaping amenities that also provide stormwater quality  benefits.  In addition, the City of Fort Collins requires that 75% of all newly added or  modified impervious area be treated by LID techniques. LID techniques are a  distributed stormwater runoff control that simulates natural processes and  relies on filtration and infiltration to locally treat  and  manage stormwater  runoff. The area of new or modified impervious area for this site is 5,700  square feet.  2. Site BMPs:  100% of the runoff from added and modified impervious areas will  be conveyed overland into the proposed rain garden prior to overflowing into  the detention pond once WQCV is reached. The raingarden is designed to  infiltrate and filter the water contained within it. The water volume exceeding  the WQCV storm event collects in the detention basin. This further allows  sediment an opportunity to settle out of storm flows prior to entering the  stormwater system.   VI. Conclusions  A. Compliance with Standards  1. Criteria:  To the best of my knowledge, the drainage design set forth in the plans  and specifications complies with the Fort Collins Stormwater Criteria Manual.    14    2. Major Drainageway Planning Studies:  To the best of my knowledge, the drainage  design  set  forth  in  the  plans  and  specifications  complies  with any  Planning  Studies.    3. Manual:  To the best of my knowledge, the drainage design set forth in the plans  and specifications complies with the Fort Collins Stormwater Criteria Manual.  B. Drainage Concept  1. Effectiveness of drainage design to control damage from storm runoff:  The  proposed design provides two permanent BMPs by means of a rain garden and  detention  basin  to  promote  infiltration  for  the  proposed  development  will  provide the required volumes set forth by Fort Collins standards.    2. Influence of proposed development of the Major Drainageway Planning Studies  recommendations(s):  Current historic drainage patterns will be maintained and  an emergency overflow route from water quality/detention pond will convey  flows into West Drake Road right of way as it currently does today. There will be  no  negative  impacts  downstream  due  to  the  runoff  from  the  proposed  development.        VII. References    1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, December, 2018.    2. Final Drainage Study and Erosion Control Report‐ Foothills Unitarian Church  Expansion, Landmark Engineering, Loveland, CO, April 3, 1996.    VIII. APPENDIX                                                      A.  VICINTIY, FIRM & SOILS MAP                 W. DRAKE ROAD S. TAFT HILL ROAD National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 6/3/2021 at 10:46 AM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°6'56"W 40°33'26"N 105°6'18"W 40°32'58"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 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 FOOTHILLS UNITARIAN CHURCH Natural Resources Conservation Service June 3, 2021 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 4—Altvan-Satanta loams, 3 to 9 percent slopes.........................................15 References............................................................................................................18 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 44891324489141448915044891594489168448917744891864489132448914144891504489159448916844891774489186490621 490630 490639 490648 490657 490666 490675 490684 490693 490702 490621 490630 490639 490648 490657 490666 490675 490684 490693 490702 40° 33' 12'' N 105° 6' 38'' W40° 33' 12'' N105° 6' 35'' W40° 33' 10'' N 105° 6' 38'' W40° 33' 10'' N 105° 6' 35'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 15 30 60 90 Feet 0 5 10 20 30 Meters Map Scale: 1:385 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 15, Jun 9, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 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 3 Altvan-Satanta loams, 0 to 3 percent slopes 0.4 97.8% 4 Altvan-Satanta loams, 3 to 9 percent slopes 0.0 2.2% Totals for Area of Interest 0.4 100.0% 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, Custom Soil Resource Report 11 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 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 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 content:10 percent Available water capacity: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:Terraces, structural benches Landform position (three-dimensional):Side slope, tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 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 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 content:10 percent Available water capacity: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 4—Altvan-Satanta loams, 3 to 9 percent slopes Map Unit Setting National map unit symbol: jpwf Elevation: 5,200 to 6,200 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Farmland of statewide importance Map Unit Composition Altvan and similar soils:55 percent Satanta and similar soils:35 percent Minor components:10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform:Fans, benches, terraces Landform position (three-dimensional):Base slope, side slope, tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Mixed alluvium Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 16 inches: clay loam, loam, sandy clay loam H2 - 9 to 16 inches: loam, fine sandy loam, silt loam H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 16 to 31 inches: H3 - 16 to 31 inches: H3 - 16 to 31 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: H4 - 31 to 60 inches: Properties and qualities Slope:6 to 9 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.60 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:10 percent Custom Soil Resource Report 15 Available water capacity:Very high (about 13.7 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e 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 14 inches: loam, clay loam, sandy clay loam H2 - 9 to 14 inches: loam, clay loam, fine sandy loam H2 - 9 to 14 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: H3 - 14 to 60 inches: Properties and qualities Slope:3 to 6 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.60 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:10 percent Available water capacity:Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Hydric soil rating: No Minor Components Nunn Percent of map unit:6 percent Hydric soil rating: No Larimer Percent of map unit:4 percent Hydric soil rating: No Custom Soil Resource Report 16 Custom Soil Resource Report 17 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 18 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 19                                                           B.  HYDROLOGICAL COMPUTATIONS                    = FORMULA CELLS = USER INPUT CELLS PROJECT: JOB NO.: CALC. BY: ▼ DATE: ▼▼ Minutes 5 10 20 30 40 50 60 120 Equation 5-1 I=(28.5*P1)/(10+Td)^0.786 I = rainfall intensity (inches per hour) P1 = 1-hour point rainfall depth (inches) Td = storm duration (minutes) Reference: 1) Fort Collins Stormwater Criteria Manual, December 2018 0.82 2.86 9.95 0.82 User Input Project Location P1: 1-hour Rainfall Depths (inches) 1.07 0.92 1.30 4.52 3.74 3.23 Foothills Unitarian Church CO3355 LTV 8/3/2021 IDF Rainfall Data 2-Year Minor Storm Major Storm Td 100-Year 2.85 2.21 1.61 7.72 5.60 1.840.49 2.86 Baseline Engineering, Planning and Surveying 8/3/2021 CO3355_SF2 SF3-Revised 2017 Standards - Site PROJECT: JOB NO.: CALC. BY: DATE: Runoff Coefficients - from FCSCM Table 3.2-2 Asphalt, Concrete 0.95 0 Rooftop 0.95 0 Lawns, sandy soil, Avg Slope 0.15 0 Land Use 0 0 SOIL TYPE:B = FORMULA CELLS = USER INPUT CELLS Basin Area (ac)C2 C5 C10 C100 Asphalt, Concrete Rooftop Lawns, sandy soil, Avg Slope Land Use Land Use Land Use Land Use Land Use A3-1 0.233 0.95 0.95 0.95 1.00 0.233 Basin Area (ac)C2 C5 C10 C100 Asphalt, Concrete Rooftop Lawns, sandy soil, Avg Slope Land Use Land Use Land Use Land Use Land Use A3-2 0.518 0.15 0.15 0.15 0.19 0.518 Basin Area (ac)C2 C5 C10 C100 Asphalt, Concrete Rooftop Lawns, sandy soil, Avg Slope Land Use Land Use Land Use Land Use Land Use A3-3 0.123 0.15 0.15 0.15 0.19 0.123 Basin Area (ac)C2 C5 C10 C100 Asphalt, Concrete Rooftop Lawns, sandy soil, Avg Slope Land Use Land Use Land Use Land Use Land Use P1 0.882 0.48 0.48 0.48 0.60 0.027 0.337 0.518 Areas (ac) Areas (ac) EXISTING PERVIOUS AREAS TO REMAIN PERVIOUS AREAS EXISTING PERVIOUS AREAS TO CHANGE TO IMPERVIOUS AREAS DEVELOPED CONDITIONS Areas (ac) Weighted C Values Weighted C Values Weighted C Values Weighted C Values Areas (ac) Land Use Land Use Land Use Land Use Foothills Unitarian Church CO3355 LTV 8/3/2021 EXISTING IMPERVIOUS AREAS Baseline Engineering, Planning and Surveying COMPOSITE C VALUES - PROP 8/3/2021 CO3355_SF2 SF3-Revised 2017 Standards - Site Project: Foothills Unitarian ChurchJob No.: CO3355Checked By: xxxxxxxxxxFINAL REMARKStcBasinCXCFAREA LENGTH SLOPEtiLENGTH SLOPE VEL.ttCOMP. TOT. LENGTH tc tcAc Ft % Min Ft % FPS MintcFt Max MinA3-1 0.95 0.23 76 2.0 9.01 165 0.030 0.1450 6.1 3.39 0.81 9.8 241 11.34 5.0 9.82 Minor StormA3-1 1.00 0.23 76 2.0 6.01 165 0.030 0.1450 6.1 3.39 0.8 6.8 241 11.34 5.0 6.8 Major StormA3-2 0.15 0.52 76 2.0 57.06 165 0.030 0.1450 6.1 3.4 0.8 57.9 241 11.34 5.0 11.3 Minor StormA3-2 0.19 0.52 76 2.0 54.80 165 0.030 0.1450 6.1 3.4 0.8 55.6 241 11.34 5.0 11.3 Major StormA3-3 0.15 0.12 76 2.0 57.06 165 0.030 0.1450 6.1 3.4 0.8 57.9 241 11.34 5.0 11.3 Minor StormA3-3 0.19 0.12 76 2.0 54.80 165 0.030 0.1450 6.1 3.4 0.8 55.6 241 11.34 5.0 11.3 Major StormP1 0.48 0.88 90 2.0 40.52 265 0.030 1.05 6.6 13.2 0.3 40.9 355 11.97 5.0 12.0 Minor StormP1 0.60 0.88 90 2.0 32.68 265 0.030 1.05 6.6 13.2 0.3 33.0 355 11.97 5.0 12.0 Major Storm= FORMULA CELLS= USER INPUT CELLSSTANDARD FORM SF-2INITIAL/OVERLANDTIME (ti)LTVDATASUB-BASIN8/3/2021DEVELOPED CONDITIONSTIME OF CONCENTRATION SUMMARYtc CHECKTRAVEL TIME(tt)REXISTING IMPERVIOUS AREASEXISTING PERVIOUS AREAS TO REMAIN PERVIOUS AREASEXISTING PERVIOUS AREAS TO CHANGE TO IMPERVIOUS AREASnBaseline Engineering,Planning and SurveyingTOC8/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Site Calculated By: Project: Foothills Unitarian ChurchDate: Job No.: CO3355Checked By: Design Storm: 2-Year= FORMULA CELLS= USER INPUT CELLSDESIGN POINTAREA DESIGNAREA (AC)RUNOFF COEFF tc (MIN)C * A (AC)I (IN/HR)Q (CFS)tc (MIN)S (C * A) (CA)I (IN/HR)Q (CFS)SLOPE (%)STREET FLOWDESIGN FLOW (CFS)SLOPE (%)PIPE DIAM. (IN.) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21)(22)A3-1 0.23 0.95 9.8 0.22 2.210.488A3-2 0.52 0.15 11.3 0.08 2.130.165A3-3 0.12 0.15 11.3 0.02 2.130.039Used to determine max allowable release rateP1 0.88 0.48 12.0 0.42 2.050.868Used as allowable release rate for WQCVSTANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)LTV8/3/2021xxxxxxxxxx2-Year0.821-hour rainfall=VELOCITY (FPS)tt (MIN)REMARKSBASINDIRECT RUNOFF TOTAL RUNOFF STREET PIPELENGTH (FT)Baseline Engineering,Planning and SurveyingMinor SF-38/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Site Calculated By: Project: Foothills Unitarian ChurchDate: Job No.: CO3355Checked By: Design Storm: 100-Year= FORMULA CELLS= USER INPUT CELLSDESIGN POINTAREA DESIGNAREA (AC)RUNOFF COEFF tc (MIN)C * A (AC)I (IN/HR)Q (CFS)tc (MIN)S (C * A) (CA)I (IN/HR)Q (CFS)SLOPE (%)STREET FLOWDESIGN FLOW (CFS)SLOPE (%)PIPE DIAM. (IN.) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21)(22)A3-1 0.23 1.00 6.8 0.23 8.802.047Used to determine max allowable release rateA3-2 0.52 0.19 11.3 0.10 7.420.721Used to determine max allowable release rateA3-3 0.12 0.19 11.3 0.02 7.420.171P1 0.88 0.60 12.0 0.53 7.163.788LTVSTANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)BASINPIPE8/3/2021xxxxxxxxxx2.86100-Year 1-hour rainfall=LENGTH (FT)VELOCITY (FPS)tt (MIN)REMARKSDIRECT RUNOFF TOTAL RUNOFF STREETBaseline Engineering,Planning and SurveyingMajor SF-38/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Site                                                           C.  HYDRAULIC COMPUTATIONS                    Project: Foothills Unitarian Church Job No.: CO3355 Calculated By: Checked By: xxxxxxxxxx Date: BASIN Q2YR (CFS) Q100YR (CFS) A3-1 0.488 2.047 A3-2 0.165 0.721 A3-3 0.039 0.171 2.806 BASIN Q2YR (CFS) Q100YR (CFS) P1 0.868 3.788 -00 2.806 CFS DESCRIPTION Flow Summary LTV 8/3/2021 EXISTING CONDITIONS DESCRIPTION Flow rate from developed conditions Free release flows off-site Required Detention Release Rate= Flow rate from all existing impervious areas Flow rate for pervious ares to remain pervious areas Flow rate for pervious ares to convert to imperviousnes areas Used to determine max allowable release rate for the site Max Allowable Release Rate = DEVELOPED CONDITIONS Baseline Engineering, Planning and Surveying Flow Summary 8/3/2021 CO3355_SF2 SF3-Revised 2017 Standards - Site Water Quality Capture Volume, WQCV  1. Determine the WQCV in Watershed Inches WQCV = a(0.91I3‐1.19I2+0.78I)Where: WQCV =  Water Quality Capture Volume, watershed inchesa =coefficient corresponding to WQCV drain timeI = Imperviousness (%/100)Drain Time (hrs)Coefficient (a)12 0.824 0.940 1.0Coefficient, a 0.80Imperviousness, I 39WQCV = 0.14watershed inches2. Determine the required storage volume in Acre‐FeetV = (WQCV/12)A x 120%Where:V =  Required Storage Volume, acre‐feetA =  Tributary catchment area upstream, acresArea, A 0.882 acresV = 0.0124acre‐feetV = 541cubic‐feetDrain Time CoefficientsUSED TO DETERMINE WQCVBASED ON FCSCM CRITERIA. 0.601.252.806 CFS0.882 ACRESResults0.0321379Rainfall Duration (min)Rainfall Intensity (in/hr)Qin (cfs)Volumein (ft3)Qout (cfs)Volumeout (ft3)Volume detained (acre‐feet)5 9.956.58 1973.99 2.81 841.94 0.02610 7.725.11 3063.16 2.81 1683.89 0.03215 6.524.31 3880.53 2.81 2525.83 0.03120 5.603.70 4443.96 2.81 3367.77 0.02525 4.983.29 4939.94 2.81 4209.72 0.01730 4.522.99 5380.37 2.81 5051.66 0.00835 4.082.70 5666.05 2.81 5893.61 ‐0.00540 3.742.47 5935.87 2.81 6735.55 ‐0.01845 3.462.29 6177.90 2.81 7577.49 ‐0.03250 3.232.14 6408.04 2.81 8419.44 ‐0.04655 3.032.00 6612.38 2.81 9261.38 ‐0.06160 2.861.89 6808.79 2.81 10103.32 ‐0.07665 2.711.79 6989.32 2.81 10945.27 ‐0.09170 2.591.71 7193.67 2.81 11787.21 ‐0.10575 2.481.64 7380.15 2.81 12629.16 ‐0.12180 2.381.57 7554.74 2.81 13471.10 ‐0.13685 2.291.51 7723.37 2.81 14313.04 ‐0.15190 2.211.46 7892.00 2.81 15154.99 ‐0.16795 2.131.41 8028.89 2.81 15996.93 ‐0.183100 2.061.36 8173.72 2.81 16838.87 ‐0.199105 2.001.32 8332.43 2.81 17680.82 ‐0.215110 1.941.28 8467.34 2.81 18522.76 ‐0.231115 1.881.24 8578.44 2.81 19364.71 ‐0.248120 1.841.22 8760.96 2.81 20206.65 ‐0.263Detention Volume Requirement (cubic‐feet)Detention Volume Requirement (acre‐feet)Detention Volume ‐ Mass Balance MethodAdditional Detention for Development Adding Over 1000 SQFT of Impervious AreaRunoff Coefficient, C =Frequency Factor, Cf =Max Release, Qout =Area = USED TO DETERMINE THE ADDITIONAL  REQUIRED VOLUME BASED ON FORT COLLINS INCREASED IMPERVIOUS CRITERIA. Project: Foothills Unitarian Church Job No.: CO3355 Calculated By: LTV Checked By: xxxxxxxxxx Date: 8/2/2021 DESIGN EVENT TOTAL AREA (ACRES) WQCV 0.88 100 YR DETENTION 0.88 REQUIRED VOLUME SUMMARY REQUIRED VOLUME (ACRE-FT) 0.012 0.032 PERCENT IMPERVIOUS REQUIRED VOLUME (FT3) 39% 541 39% 1379 Baseline Engineering, Planning and Surveying VOLUME SUMMARY 8/11/2021 CO3355_Fort Collins Rational Method Spreadsheet ‐ Site Extended Detention Basin Outlet Structure Orifice Sizing 1. 100‐yr Orifice at EDB for 40‐hour drain time (using orifice equation) a. Use Orifice Equation to solve for orifice diamter Q =CoA√2gh Where: Q = flow rate or allowable discharge, cfs Co =orifice coefficient, typically 0.61 A =cross‐sectional area, ft2 g =gravitational constant, 32.2 ft/sec2 h = water surface elevation minus elevation of centroid of orifice, ft Q = 2.81 cfs Co =0.61 dimensionless h =1.60 ft A = 0.453 ft2 orifice diameter = 9.12 inches USE =9.00 inches Spillway Overflow Depth Check Q =CBCWLH1.5 Equation 6‐5, FCSCM Where: Q =  Discharge, cfs CBCW =Broad‐crested weir coeff. dimensionless (ranges from 2.6 to 3.0) L = Length of weir, ft H = Head above weir crest, ft Q =  6.58 cfs CBCW =2.63 dimensionless L =  7 ft H =  0.50 <= 0.50 ft. OK 2. Flow over a horizontal spillway can be calculated using the following equation for a horizontal broadcrested  weir: PROJECT : PROJECT LOCATION: Fort Collins DATE : PROJECT NO. :BY : Provided Volume Stage (ft) Contour Elevation (ft) 0.00 5066.36 0.59 5066.95 WQCV =5066.95 0.59 1,154.99 541.32 0.012 EURV = 2‐yr = 5‐yr = 10‐yr = 100‐yr = = FORMULA CELLS = USER INPUT CELLS Volume  (ac‐ft) Area (ft2) 699 1,155 541 WSEL Depth (ft) Area      (ft2)  Volume  (ft3) 8/11/2021 LTV Foothills Unitarian  CO3355 Rain Garden Volume Calculation 0.0 541 1/3 (A1 + A2 + (A1A2)1/2) D Total Volume (ft3) Total Volume (ac- ft) 0.000 0.012 PROJECT : PROJECT LOCATION: Fort Collins DATE : PROJECT NO. :BY : Provided Volume Stage (ft) Contour Elevation (ft) 0.00 5065.25 0.25 5065.50 0.75 5066.00 1.70 5066.95 WQCV = EURV = 2‐yr = 5‐yr = 10‐yr = 100‐yr =5066.85 1.60 1,435.84 1,389.56 0.032 = FORMULA CELLS = USER INPUT CELLS WSEL Depth (ft) Area      (ft2)  Volume  (ft3) Volume  (ac‐ft) 8/11/2021 LTV Foothills Unitarian  CO3355 Area (ft2) 330 472 814 1,509 100 318 1,087 0.0 100 417 1,504 Detention Basin Volume Calculation 1/3 (A1 + A2 + (A1A2)1/2) D Total Volume (ft3) Total Volume (ac- ft) 0.000 0.002 0.010 0.035 Q =CoA√2gh Where: Q = flow rate or allowable discharge, cfs Co =orifice coefficient, typically 0.61 A =cross‐sectional area, ft2 g =gravitational constant, 32.2 ft/sec2 h = water surface elevation minus elevation of centroid of orifice, ft Stage (ft) Theta Area of Orifice (ft^2) Discharge (cfs) 0 0.00 0.000 0.00 0.1 1.50 0.035 0.05 0.2 2.17 0.095 0.20 0.3 2.74 0.165 0.44 0.4 3.01 0.240 0.74 0.5 2.46 0.313 1.08 0.6 1.85 0.379 1.43 0.7 1.04 0.429 1.75 0.8 N/A‐Full flow 0.442 1.93 0.9 N/A‐Full flow 0.442 2.05 1 N/A‐Full flow 0.442 2.16 1.1 N/A‐Full flow 0.442 2.26 1.2 N/A‐Full flow 0.442 2.36 1.3 N/A‐Full flow 0.442 2.46 1.4 N/A‐Full flow 0.442 2.55 1.5 N/A‐Full flow 0.442 2.64 1.6 N/A‐Full flow 0.442 2.73 1.7 N/A‐Full flow 0.442 2.81 This table was used to fill out the Stage‐Discharge table on the State SDI data worksheet Stormwater Facility Name: Facility Location & Jurisdiction: User Input: Watershed Characteristics User Defined User Defined User Defined User Defined Watershed Slope =0.020 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs] Watershed Length =355 ft 0.00 330 0.00 0.00 Watershed Area = 0.88 acres 0.25 472 0.10 0.05 Watershed Imperviousness = 38.6%percent 0.75 814 0.20 0.20 Percentage Hydrologic Soil Group A = 0.0%percent 1.70 1,509 0.30 0.44 Percentage Hydrologic Soil Group B = 100.0%percent 0.40 0.74 Percentage Hydrologic Soil Groups C/D = 0.0%percent 0.50 1.08 0.60 1.43 User Input 17 0.70 1.75 0.80 1.93 0.90 2.05    1.00 2.16 WQCV Treatment Method = 12.00 hours 1.10 2.26 1.20 2.36 1.30 2.46 1.40 2.55 1.50 2.64 1.60 2.73 1.70 2.81 After completing and printing this worksheet to a pdf, go to: https://maperture.digitaldataservices.com/gvh/?viewer=cswdif create a new stormwater facility, and  attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period =WQCV 2 Year 5 Year 10 Year 50 Year 100 Year One‐Hour Rainfall Depth =0.40 0.30 0.42 0.52 0.67 1.06 in Calculated Runoff Volume =0.010 0.007 0.011 0.017 0.031 0.055 acre‐ft OPTIONAL Override Runoff Volume =acre‐ft Inflow Hydrograph Volume =0.010 0.007 0.010 0.016 0.031 0.054 acre‐ft Time to Drain 97% of Inflow Volume =1.9 1.9 1.9 1.8 1.7 1.6 hours Time to Drain 99% of Inflow Volume =2.5 2.5 2.5 2.5 2.5 2.5 hours Maximum Ponding Depth =0.16 0.12 0.16 0.21 0.30 0.41 ft Maximum Ponded Area =0.01 0.01 0.01 0.01 0.01 0.01 acres Maximum Volume Stored =0.001 0.001 0.001 0.002 0.003 0.004 acre‐ft Location for 1‐hr Rainfall Depths (use dropdown): Workbook Protected Worksheet Protected Stormwater Detention and Infiltration Design Data Sheet Foothills Unitarian Church Detention (WQ Provided by Upstream Rain Garden) 1815 Yorktown Ave, Fort Collins, CO 80526, City of Fort Collins SDI_Design_Data_v1.08, Design Data 1/10/2022, 4:52 PM WQCV_Trigger = 1 RunOnce= 1 CountA=1 Draintime Coeff=0.8 0123 #N/A #N/A 0123 #N/A #N/A Check Data Set 1 Check Data Set 1 Area Discharge Stormwater Detention and Infiltration Design Data Sheet 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.1 1 10FLOW [cfs]TIME [hr] 100YR IN 100YR OUT 50YR IN 50YR OUT 10YR IN 10YR OUT 5YR IN 5YR OUT 2YR IN 2YR OUT WQCV IN WQCV OUT 0 0.2 0.4 0.6 0.8 1 1.2 0.1 1 10 100PONDING DEPTH [ft]DRAIN TIME [hr] 100YR 50YR 10YR 5YR 2YR WQCV SDI_Design_Data_v1.08, Design Data 1/10/2022, 4:52 PM                                                           D.  CURB HYDROLOGICAL COMPUTATIONS                    PROJECT: JOB NO.: CALC. BY: DATE: Runoff Coefficients - from FCSCM Table 3.2-2 Asphalt, Concrete 0.95 0 Rooftop 0.95 0 Lawns, sandy soil, Avg Slope 0.15 0 Land Use 0 0 SOIL TYPE:B = FORMULA CELLS = USER INPUT CELLS Basin Area (ac)C2 C5 C10 C100 Asphalt, Concrete Rooftop Lawns, sandy soil, Avg Slope Land Use Land Use Land Use Land Use Land Use C-1 3.039 0.51 0.51 0.51 0.63 0.767 0.591 1.681 C-2 0.118 0.88 0.88 0.88 1.00 0.108 0.010 C-3 0.375 0.71 0.71 0.71 0.89 0.218 0.044 0.113 Weighted C Values Areas (ac) Land Use Land Use Land Use Land Use Foothills Unitarian Church CO3355 LTV 8/3/2021 EXISTING AREAS Baseline Engineering, Planning and Surveying COMPOSITE C VALUES - PROP 8/3/2021 CO3355_SF2 SF3-Revised 2017 Standards - Curb Project: Foothills Unitarian ChurchJob No.: CO3355Checked By: xxxxxxxxxxFINAL REMARKStcBasinCXCFAREA LENGTH SLOPEtiLENGTH SLOPE VEL.ttCOMP. TOT. LENGTH tc tcAc Ft % Min Ft % FPS MintcFt Max MinC-1 0.51 3.04 20 2.0 18.25 924 0.015 0.0814 1.8 2.50 6.15 24.4 944 15.24 5.0 15.24 Minor StormC-1 0.63 3.04 20 2.0 14.35 924 0.015 0.0814 1.8 2.50 6.2 20.5 944 15.24 5.0 15.2 Major StormC-2 0.88 0.12 20 2.0 6.71 210 0.015 0.0814 1.0 1.87 1.88 8.6 230 11.28 5.0 8.59Minor StormC-2 1.00 0.12 20 2.0 3.08 210 0.015 0.0814 1.0 1.87 1.9 5.0 230 11.28 5.0 5.0 Major StormC-3 0.71 0.38 85 3.6 20.42 391 0.015 0.0814 2.6 3.01 2.17 22.6 476 12.64 5.0 12.64 Minor StormC-3 0.89 0.38 85 3.6 11.17 391 0.015 0.0814 2.6 3.01 2.2 13.3 476 12.64 5.0 12.6 Major Storm= FORMULA CELLS= USER INPUT CELLSREXISTING IMPERVIOUS AREASnSTANDARD FORM SF-2INITIAL/OVERLANDTIME (ti)LTVDATASUB-BASIN8/3/2021TIME OF CONCENTRATION SUMMARYtc CHECKTRAVEL TIME(tt)Baseline Engineering,Planning and SurveyingTOC8/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Curb Calculated By: Project: Foothills Unitarian ChurchDate: Job No.: CO3355Checked By: Design Storm: 2-Year= FORMULA CELLS= USER INPUT CELLSDESIGN POINTAREA DESIGNAREA (AC)RUNOFF COEFF tc (MIN)C * A (AC)I (IN/HR)Q (CFS)tc (MIN)S (C * A) (CA)I (IN/HR)Q (CFS)SLOPE (%)STREET FLOWDESIGN FLOW (CFS)SLOPE (%)PIPE DIAM. (IN.) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21)(22)C-1 3.04 0.51 15.2 1.54 1.872.884C-2 0.12 0.88 8.6 0.10 2.300.239C-3 0.38 0.71 12.6 0.27 1.980.526STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)LTV8/3/2021xxxxxxxxxxREMARKSBASINDIRECT RUNOFF TOTAL RUNOFF STREET PIPELENGTH (FT)VELOCITY (FPS)tt (MIN)Baseline Engineering,Planning and SurveyingMinor SF-38/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Curb Calculated By: Project: Foothills Unitarian ChurchDate: Job No.: CO3355Checked By: Design Storm: 100-Year= FORMULA CELLS= USER INPUT CELLSDESIGN POINTAREA DESIGNAREA (AC)RUNOFF COEFF tc (MIN)C * A (AC)I (IN/HR)Q (CFS)tc (MIN)S (C * A) (CA)I (IN/HR)Q (CFS)SLOPE (%)STREET FLOWDESIGN FLOW (CFS)SLOPE (%)PIPE DIAM. (IN.) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21)(22)C-1 3.04 0.63 15.2 1.93 6.5212.569C-2 0.12 1.00 5.0 0.12 9.951.174C-3 0.38 0.89 12.6 0.33 6.922.300LTVSTANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)BASINPIPE8/3/2021xxxxxxxxxxLENGTH (FT)VELOCITY (FPS)tt (MIN)REMARKSDIRECT RUNOFF TOTAL RUNOFF STREETBaseline Engineering,Planning and SurveyingMajor SF-38/3/2021CO3355_SF2 SF3-Revised 2017 Standards - Curb Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C1 2YR GUTTER SPREAD Gutter Cross Sl, Sx (ft/ft) = 0.020 Cross Sl, Sw (ft/ft) = 0.083 Gutter Width (ft) = 2.00 Invert Elev (ft) = 100.00 Slope (%) = 2.27 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 2.88 Highlighted Depth (ft) = 0.28 Q (cfs) = 2.880 Area (sqft) = 0.72 Velocity (ft/s) = 4.01 Wetted Perim (ft) = 7.99 Crit Depth, Yc (ft) = 0.36 Spread Width (ft) = 7.70 EGL (ft) = 0.53 0 2 4 6 8 10 12 14 16 18 20 22 24 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C1 100YR GUTTER SPREAD Gutter Cross Sl, Sx (ft/ft) = 0.020 Cross Sl, Sw (ft/ft) = 0.083 Gutter Width (ft) = 2.00 Invert Elev (ft) = 100.00 Slope (%) = 2.27 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 12.57 Highlighted Depth (ft) = 0.42 Q (cfs) = 12.57 Area (sqft) = 2.35 Velocity (ft/s) = 5.36 Wetted Perim (ft) = 15.33 Crit Depth, Yc (ft) = 0.56 Spread Width (ft) = 14.90 EGL (ft) = 0.87 0 2 4 6 8 10 12 14 16 18 20 22 24 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C2 2YR FLOW AT 2 IN SIDEWALK User-defined Invert Elev (ft) = 100.26 Slope (%) = 1.00 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 0.24 (Sta, El, n)-(Sta, El, n)... ( 0.00, 100.50)-(5.00, 100.43, 0.015)-(5.01, 100.26, 0.015)-(25.00, 100.66, 0.015) Highlighted Depth (ft) = 0.09 Q (cfs) = 0.239 Area (sqft) = 0.20 Velocity (ft/s) = 1.18 Wetted Perim (ft) = 4.59 Crit Depth, Yc (ft) = 0.09 Top Width (ft) = 4.50 EGL (ft) = 0.11 -5 0 5 10 15 20 25 30 Elev (ft)Depth (ft)Section 100.00 -0.26 100.25 -0.01 100.50 0.24 100.75 0.49 101.00 0.74 Sta (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C2 100YR FLOW AT 2 IN SIDEWALK User-defined Invert Elev (ft) = 100.26 Slope (%) = 1.00 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 1.17 (Sta, El, n)-(Sta, El, n)... ( 0.00, 100.50)-(5.00, 100.43, 0.015)-(5.01, 100.26, 0.015)-(25.00, 100.66, 0.015) Highlighted Depth (ft) = 0.17 Q (cfs) = 1.174 Area (sqft) = 0.72 Velocity (ft/s) = 1.62 Wetted Perim (ft) = 8.67 Crit Depth, Yc (ft) = 0.17 Top Width (ft) = 8.51 EGL (ft) = 0.21 -5 0 5 10 15 20 25 30 Elev (ft)Depth (ft)Section 100.00 -0.26 100.25 -0.01 100.50 0.24 100.75 0.49 101.00 0.74 Sta (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C3 2YR FLOW AT 2 IN SIDEWALK User-defined Invert Elev (ft) = 100.26 Slope (%) = 2.10 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 0.53 (Sta, El, n)-(Sta, El, n)... ( 0.00, 100.50)-(5.00, 100.43, 0.015)-(5.01, 100.26, 0.015)-(25.00, 100.66, 0.015) Highlighted Depth (ft) = 0.11 Q (cfs) = 0.526 Area (sqft) = 0.30 Velocity (ft/s) = 1.74 Wetted Perim (ft) = 5.61 Crit Depth, Yc (ft) = 0.13 Top Width (ft) = 5.50 EGL (ft) = 0.16 -5 0 5 10 15 20 25 30 Elev (ft)Depth (ft)Section 100.00 -0.26 100.25 -0.01 100.50 0.24 100.75 0.49 101.00 0.74 Sta (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 4 2021 C3 100YR FLOW AT 2 IN SIDEWALK User-defined Invert Elev (ft) = 100.26 Slope (%) = 2.10 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 2.30 (Sta, El, n)-(Sta, El, n)... ( 0.00, 100.50)-(5.00, 100.43, 0.015)-(5.01, 100.26, 0.015)-(25.00, 100.66, 0.015) Highlighted Depth (ft) = 0.19 Q (cfs) = 2.300 Area (sqft) = 0.92 Velocity (ft/s) = 2.51 Wetted Perim (ft) = 11.10 Crit Depth, Yc (ft) = 0.23 Top Width (ft) = 10.93 EGL (ft) = 0.29 -5 0 5 10 15 20 25 30 Elev (ft)Depth (ft)Section 100.00 -0.26 100.25 -0.01 100.50 0.24 100.75 0.49 101.00 0.74 Sta (ft)                                                         E. DRAINAGE DETAILS AND PLANS              This unofficial copy was downloaded on Jun-18-2021 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA T Know what's below. before you dig.CallR T Know what's below. before you dig.CallR DEVELOPED RUNOFF SUMMARY BASIN ID DESIGN POINT AREA (ACRES) TC (MIN) NEW AND MODIFIED IMPERVIOUS AREA IMPERVIOUSNESS C2 C100 Q2 (CFS) Q100 (CFS) STORMWATER DETENTION FACILITIES DESIGN PARAMETERS TOTAL PROPERTY AREA TRIBUTARY AREA OF DETENTION EXISTING IMPERVIOUSNESS OF TRIBUTARY PROPOSED IMPERVIOUSNESS OF TRIBUTARY CHANGE IN IMPERVIOUSNESS ALLOWABLE 100 YEAR RELEASE RATE VOLUME OF 100 YEAR STORM EVENT WQCV RAIN GARDEN FACILITY DESIGN PARAMETERS DETENTION VOLUME (WQCV) WSEL WQCV BOTTOM OF POND SPILLWAY ELEVATION TOP OF POND FREEBOARD DETENTION POND FACILITY DESIGN PARAMETERS DETENTION VOLUME (100YR-WQCV) WSEL 100YR BOTTOM OF POND SPILLWAY ELEVATION TOP OF POND FREEBOARD Know what's below. before you dig.CallR DEVELOPED RUNOFF SUMMARY BASIN ID DESIGN POINT AREA (ACRES) TC (MIN)C2 C100 Q2 (CFS) Q100 (CFS) COLO R A D O L IC E NSEDPROFE S SIONA L E N G INEER53301 JORDAN T . PIA S KOWYKnow what's below. before you dig.CallR CC A A B B SECTION C-C SECTION A-A SECTION B-B WELL SCREEN FLOW CONTROL PLATE PLAN GENERAL NOTES SECTION D-D D D A A ABBREVIATIONS LEGEND COLO R A D O L IC E NSEDPROFE S SIONA L E N G INEER53301 JORDAN T . PIA S KOWYKnow what's below. before you dig.CallR 6" AMENDED TOP SOIL                                                     F.  Erosion Control Plans and Details     Know what'sR Know what'sR Know what'sR