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Home My WebLink AboutDrainage Reports - 12/07/2017City of Ft. Collins proxed Plans Approved By �� Date 1 z - -7 - 17 oo;�E 10 :,L 11/ 17i� •� ,In 46595: AThis 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. November 9, 2017 Schrader Propane Offices Fort Collins, Colorado Prepared for: Schrader Propane 320 North College Avenue Fort Collins, CO 80524 970-484-1225 Prepared by: NORTHERN ENGINEERING 301 N. Howes Street, Suite 100 Fort Collins, Colorado 80521 Phone: 970.221.4158 www.northernengineering.com Project Number: 146-011 • Nnrf6prnFnninaa rinn.rnm /! 07n. 771.4148 NORTHERN ENGINEERING RE: Final Drainage and Erosion Control Report for Schrader Propane Offices Dear Staff: Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies Final Development Plan submittal for the proposed Schrader Propane Offices development. This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM), and serves to document the stormwater impacts associated with the proposed 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. Stephanie Thomas, PE Project Engineer 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 1 970.221.4158 1 www.northernengineering.com ' NORTHERN ENGINEERING Schrader Proaane Offices iTABLE 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....................................................................... 4 ' A. B. Major Basin Description...............................................................................................................4 Sub -Basin Description . ..4 ' III. A. DRAINAGE DESIGN CRITERIA................................................................................... Regulations..................................................................................................................................5 5 B. Four Step Process........................................................................................................................5 ' C. Development Criteria Reference and Constraints.........................................................................6 D. Hydrological Criteria....................................................................................................................6 ' E. Hydraulic Criteria.........................................................................................................................6 F. Floodplain Regulations Compliance..............................................................................................6 ' G. Modifications of Criteria.............................................................................................................. 6 IV. DRAINAGE FACILITY DESIGN.................................................................................... 7 ' A. General Concept..........................................................................................................................7 B. Specific Details.............................................................................................................................9 ' V. CONCLUSIONS........................................................................................................9 A. Compliance with Standards..........................................................................................................9 ' B. Drainage Concept...................................................................................................................... References....................................................................................................................... 10 11 ' APPENDICES: APPENDIX A — Hydrologic Computations APPENDIX B — Hydraulic Computations ' B.1 — Detention Ponds and Water Quality B.2 — Storm Sewers B.3 — Inlets ' APPENDIX APPENDIX C — Erosion Control Report D — LID Exhibit APPENDIX E — References 1 Preliminary Drainage Report ' (NORTHERN ENGINEERING LIST OF TABLES AND FIGURES: Figure1 —Aerial Photograph................................................................................................ 2 1 Figure 2— Proposed Site Plan................................................................................................ 3 Figure 3 — Existing Floodplains............................................................................................. 4 MAP POCKET: DR1 - Drainage Exhibit 1 1 1 1 1 i 1 1 1 1 1 1 1 1 Preliminary Drainage Report ' ■� NORM HERN ENGIEERING Schrader Propane Offices ' I. GENERAL LOCATION AND DESCRIPTION ' A. Location 1. Vicinity Map [1 1 11 1 VICINITY MAP NORTH 2. Lot 1, Evergreen Park Fifth Filing. Located in the northwest quarter of Section 1, Township 7 North, Range 69 West of the 6' Prime Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. Bounded to the north by industrial lot, to the west by an existing alley, to the south by undeveloped lot and transmission lines, and to the east by public right of way for Red Cedar Circle. ' 4. No significant offsite flows are directed into the site. The majority of off -site flows are are prevented from entering the site by existing topography. 5. This lot was originally included in the Master Storm Drainage and Detention Plan for Evergreen Park, prepared by Cornell Consulting Company. The Drainage Plan for the area has been revised per the North East College Corridor Outfall (NECCO) project Final Drainage Report 1 NORTHERN ENG!NEF R ! N G Schrader Propane Offices commissioned by The City of Fort Collins and designed by Ayres Associates. 6. The NECCO project overrides the existing drainage plan for the Evergreen Park Subdivision. B. Description of Property 1. The site is approximately 1.63 acres with 1.06 acres planned for development. i Figure 1 — Aerial Photograph 2. The existing site is comprised of undeveloped land with natural grasses and vegetation. The southern boundary of the site contains a watermain and overhead electric lines. 3. The majority of the site slopes to the alley and Red Cedar Circle, while gently slopes to the south. The site generally is very flat except along the eastern boundary. 4. A Web Soil Survey from the Natural Resources Conservation Service lists the soils for the area as Hydrologic Soil Group C and have a low infiltration rate. 5. The proposed project site plan is composed of 1 commercial building, four detention Final Drainage Report 2 NORTHERN ENGINEERING Schrader Propane Offices ponds, concrete parking, concrete drives, and gravel yard/parking. This site will employ water quality features and runoff reduction facilities including underground water quality chambers. III Figure 2— Proposed Site Plan 6. No existing irrigation facilities are known at this time. 7. The project site is within the Evergreen Park Subdivision Drainage Plan and the NECCO drainage basin. The proposed project is not requesting a change in the land use. C. Floodplain 1. The subject property is not located in a FEMA or City regulatory floodplain. Final Drainage Report 3 W INORTHERN ENGINEERING hrader Propane FCMaps c Y a V i t Cwm r. �a w"Ils Figure 3 — Existing Floodplains II. DRAINAGE BASINS AND SUB -BASINS A. Major Basin Description 1. The Schrader project is located within the Dry Creek Master Drainage Basin. B. Sub -Basin Description 1. The existing western half of the property generally drains to the western alley. From there, flows are conveyed along the alley to Conifer Street and to existing downstream inlets. 2. The existing eastern half of the site generally drains to Red Cedar Circle. From there, the flows are conveyed along the street curb and gutter to Conifer Street and to existing downstream inlets. 3. The proposed plan will generally detain developed flows and release to the Red Cedar Circle curbline. Final Drainage Report 4 ,V (NORTHERN ENGINEERING Schrader Propane Office ' Ill. DRAINAGE DESIGN CRITERIA ' A. Regulations This project is requesting an increased release rate greater than the historic 2-yr. The detention ponds are proposed to release into the existing street curbline. To create ' detention on -site, the site driveway was built up in order to detain above the existing curbline. As such, runoff from the proposed driveway was unable to be completely detained and released at the 2-yr historic rate. A small pond is proposed to attenuate the ' majority of the driveway flows. B. Four Step Process The overall stormwater management strategy employed with Schrader Propane Offices 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 Specific 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: Routing flows, to the extent feasible, through StormTech Isolator chambers to remove ' sediment migration. N= Providing on -site detention to increase time of concentration, promote infiltration and reduce loads on existing storm infrastructure. Providing gravel parking area in the western portion of the site to reduce the overall impervious area and to minimize directly connected impervious areas (MDCIA). ' 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 LID strategies listed above will provide the water quality treatment required for this project. Additional water quality for this site is provided by the NECCO ' drainage project within the downstream extended detention ponds. Step 3 — Stabilize Drainageways There are no major drainageways within the subject property. This property discharges to existing curb and gutter. ' Step 4 — Implement Site Specific and Other Source Control BMPs. The proposed project will improve upon site specific source controls compared to historic ' conditions: N= Localized trash enclosures within the development will allow for the disposal of solid waste. ' Stormtech Underground Chambers for water treatment prior to flows entering the extended detention basins. w Water Quality measures to protect and prolong the design life of the BMPs delineated in Step 1. ' Final Drainage Report 5 ' ■� (NORTHERN ENGINEERING Schrader Propane Office C. Development Criteria Reference and Constraints ' 1. The proposed site is a part of the NECCO project. This project requires this site to discharge runoff from the 100-yr storm event at the historic 2-year release rate. 2. This site is subject to the LID requirements per the City of Fort Collins. Please see the ' LID Exhibit located in the Appendix for calculations concerning LID treatment. The site must either have the following: w 75% of total new impervious areas must be treated through an LID (Low, Impact ' Development) treatment BMP, or w 50% of total new impervious areas must be treated through an LID (Low Impact Development) treatment BMP and 25% of new pavement shall be pervious. ' 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 the 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. t 1 1 1 3. The FAA Modified method was utilized for detention storage calculations and maximum release from the site during a 100-yr event. 4. Three separate design storms have been utilized to address distinct drainage scenarios. The first event analyzed is the "Minor," or "Initial" Storm, which has a 2- year recurrence interval. The second event considered .is the "Major Storm," which has a 100-year recurrence interval. The third 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 to the west and east. 2. All drainage facilities proposed with the Schrader Propane Offices 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 previously, the subject property is not located within a FEMA regulatory floodplain. 4. The Schrader Propane Offices 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 floodplain, and thus are not subject to any floodplain regulations. G. Modifications of Criteria 1. This project is requesting an increased release rate greater than the historic 2-yr. 1 Final Drainage Report 6 ' INORTHERN ENGINEERING Schrader Propane Office. ' IV. DRAINAGE FACILITY DESIGN ' A. General Concept 1. The main objectives of the Schrader drainage design are to minimize the developed 100-yr event discharge from the site and meet LID treatment requirements. ' 2. The site is constrained by a lack of accessible drainage outfall. The site has been designed to store runoff above and release to the existing Red Cedar Circle curb and ' gutter. 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. Historic runoff from Schrader Propane Offices project site was evaluated. This evaluation provided the historic 2-yr, 10-yr, and 100-yr peak runoff rates for the ' existing site. The 1.06 acre site was evaluated to have a historic 2-yr, 10-yr and 100-yr runoff of ' 0.29 cfs, 0.50 cfs, and 1.32 cfs, respectively. This is higher than the published 0.20 cfs/acre for the Dry Creek Master Drainage Basin 2-yr historic. 5. The Schrader project is divided the site into five (5) major drainage basins, designated ' as Basins A, B, C, D and UD. Basin A ' Basin A is a total of 0.62 acres. Basin A consists of proposed building, concrete drive, gravel parking lot, and detention pond. Runoff from Basin A flows via sheet flow to a trench drain. Stormwater from Basin A is detained in the combination of Ponds 1, 2 and 3. Basin A is treated for LID within the underground Stormtech ' chambers. Total flow during a 100-yr storm from Basin A is calculated at a 4.17 cfs. Basin B Basin B is a total of 0.19 acres. Basin B consists of proposed building, concrete parking lot, concrete drive, curb and gutter, and landscaped areas. Runoff from Basins B sheet flows to a curb and gutter and is collect in a proposed inlet. ' Stormwater from Basin B is detained in the combination of Pond 1, 2 and 3. Total flow during a 100-yr storm from Basin B is calculated at 1.89 cfs. 1 Basin C Basin C is a total of 0.05 acres. Basin C consists of Detention Pond 3. Runoff from Basin C is detained in Detention Pond 3. Total flow during a 100-yr storm from Basin ' C is calculated at 0.16 cfs. Basin D ' Basin C is a total of 0.11 acres. Basin D consists of concrete drive, proposed building, curb and gutter and detention Pond 4. Runoff from Basin D sheet flows to a trench drain and is conveyed to Detention Pond 4. Runoff from Basin D is detained in Detention Pond 4. Total flow during a 100-yr storm from Basin D is calculated at 1.02 ' Final Drainage Report 7 ■V NORTHERN ENGINEERING Schrader Propane Offices Basin LID Basin UD1 is a total of 0.06 acres. Basin UD1 consists of concrete drive, sidewalk and landscaping. Due to the constrained outfall location, the site required to be graded up from Red Cedar Circle. This area was unable to be captured on -site and conveyed to the proposed detention ponds. This basin is not detained and runoff will continue to ' flow to historic capture points. Total flow during a 100-yr storm from Basin UD1 is calculated at 0.19 cfs. Basin UD2 is a total of 0.03 acres. Basin UD2 consists of tie-in grading to existing ground. This basin is not detained and runoff will continue to flow to historic capture points. Total flow during a 100-yr storm from Basin UD2 is calculated at 0.06 cfs. 6. Four (4) detention ponds are proposed with the Schrader Propane Offices project. Detention Pond 1 is located within Basin A. Detention Pond 2 is located within Basin A. Detention Pond 3 is located within Basin C. Detention Pond 4 is located within ' Basin D. Detention Pond 1, 2 and 3 essentially function as one pond connected by storm sewer and Stormtech underground chambers. Detention Pond 3 will fill up during typical storm events. Detention Pond 3 will back up into Detention Pond 2 ' and 1 during larger storm events. ,J 1 1 11 1 Detention Pond 1. 2. and 3 Combined Detention Pond 1, 2 and 3 combined has a total of 0.19 ac-ft storage available. 0.18 ac-ft of storage is required with this project. Water quality control volume for Basin A, B and C is not included in the pond volume since water quality has been provided via LID measures upstream. Emergency Overflow from the pond is directed around the parking lot curb return and down the concrete drive to the Red Cedar Circle. Release rate from Pond 1, 2 and 3 is proposed at 0.13 cfs. Detention Pond 4 Detention Pond 4 has a total of 872 cubic feet storage available. 788 cubic feet of storage is required with this project. Water quality control volume for Basin D is not included in the pond volume since water quality has been planned downstream in the NECCO detention ponds. Emergency Overflow from the pond is directed down the concrete drive to the Red Cedar Circle. Due to the grading constraint on -site, the depth within Pond 4 was not enough for the amount of volume required for a 2-yr historic release. The release rate from Detention Pond 4 was increased to fully utilize the pond without spilling. Release rate from Pond 4 is proposed at 0.08 cfs. VMrOM • E`i�7iIT117 - :7MC-F1T.IfiiTiZ• Rational Method/FAA Calculations 100-yr stormwater release from the site is a combination of release from Detention Pond 1, 2 and 3 Combined (0.13 cfs), Detention Pond 4 (0.08 cfs), Basin LIM 100- yr runoff (0.19 cfs) and Basin UD2 100-yr runoff (0.06 cfs). The total release from the site during a 100-yr event, utilizing the rational method and FAA calculations, would be a total 0.46 cfs. The historic release from the site was calculated at 0.29 cfs. The proposed total release from the site is approximately 0.17 cfs above the historic 2-yr release. This proposed release would fall somewhere between a historic 2-yr and historic 10-yr release. Final Drainage Report 8 ' ■� NORTHERN ENGINEERING Schrader Propane Offices The additional 0.17 cfs release from the site is expected to have no negative impacts on downstream facilities or structures. Runoff reduction provided by the underground water quality chambers would help to mitigate this additional discharge from the site. ' A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. B. Water Quality Treatment/Low Impact Development 1. Water Quality is provided for the site downstream with the NECCO project. This site is only required to meet LID requirements for water quality ' 2. Basins A and B have water quality provided exclusively via StormTech chambers. Following UDFCD standards for a 12-hour drain time, a Water Quality Capture ' Volume of 526 cu. ft. is required. Using SC-160 StormTech chambers designed for water quality, 526 cu. ft. is provided within the isolator rows at a depth of 18", as shown by the stage storage calculations provided by Stormtech. The Stormtech manufacturer will has reviewed the plans and provided stage storage calculations. 1 These calculations are provided in the appendix. 3. The initial flush of stormwater will be detained within these isolators and released via ' infiltration through the aggregate section to a subdrain. Stormwater volume exceeding the volume provided in the Stormtech chambers will overflow a water quality weir within the proposed storm structures and be directed into the detention pond. 4. The Stormtech Chambers are also used as the Low Impact Development (LID) measure. The Stormtech Chambers provide LID treatment,for Basins A and B. This accounts for 84% of the on -site impervious area. Please see the Appendix for ' detailed calculations. C. Specific Details 1. Detention Ponds 1, 2, and 3 combine to form one pond for larger storm events. As such, the piping system between the ponds is expected to experience backflow as the volume of water backflows through the network to fill the upstream ponds (Detention ' Ponds 1 and 2). To better model this scenario, storm sewer system model in Hydraflow utilized a lower discharge rate from Detention Pond 1 than the hydrologic calculation. An FAA model was created to determine the maximum discharge rate ' from Detention Pond 1 in order to maintain the 100-year water surface elevation. This FAA spreadsheet is provided within the Detention Pond appendix. ' V. CONCLUSIONS A. Compliance with Standards ' 1. The drainage design proposed with the Schrader Propane Offices project complies with the City of Fort Collins' Stormwater Criteria Manual. 2. The drainage design proposed with the Schrader Propane Offices complies with the ' City of Fort Collins' Master Drainage Plan for the Dry Creek Drainage Basin, with the exception of an increased 100-yr release rate from the site. 3. There are no regulatory floodplains associated with the development. 4. The drainage plan and stormwater management measures proposed with the development are compliant with all applicable State and Federal regulations governing ' Final Drainage Report 9 ' (NORTHERN ENGINEERING 1 1 1 1 stormwater discharge. 5. The site achieves the requirements set forth by the City of Fort Collins for Low Impact Development (LID) by providing 84% total impervious areas as being treated through an LID treatment. Please see LID Exhibit located in the Appendix. B. Drainage Concept 1. The drainage design proposed with this project will effectively comply with previous studies and will limit any potential damage or erosion associated with its stormwater runoff. All existing downstream drainage facilities are expected to not be impacted negatively by this development 2. The drainage design is anticipated to be very conservative. We have omitted any runoff reduction that will manifest due to infiltration within the underground Stormtech chambers. This is currently unable to be calculated with available soils data. 1 Final Drainage Report 10 ' (NORTHERN ENGINEERING ' Rderences 1. 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. ' 2. Master Storm Drainage and Detention Plan for Evergreen Park, Cornell Consulting Company. 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. 1 1 1 1 s Final Drainage Report 11 Aw NnrthernEnnin eerina.com 11 970-771.4758 |fi |.,a■.,G��,t12� g - : ■::::: q / . f R �Ee !}| @ . . % NO �!! a§� . m 2 E ■ E� § aaa ;■■ ` o £ _ c § < «! § � E:e §k$| 2 E¥ §|kf! b E\ �} ! & E E §} $E .|. °E � \{ 2 I I I I I / I I I �\ �f + �) �\ I k¢ \ 77{« 00 - {)/ « p � r . | ! 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Thomas Date: 8/18/2017 Pond No.: Pond 1 Input Variables Results Design Point A Design Storm 100-yr Developed "C" = 0.70 Approx. Area (A)= 0.62 acres Max Release Rate = 0.80 cfs Required Detention Volume WQCV 0 ft3 Quantity Detention 2091 ft3 Total Volume 0.05 ac-ft Time Time Ft. Col I i ns 100-yr Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft) (ft) (ft ) 5 300 9.95 4.3 1295 240 1055 10 600 7.72 3.4 2010 480 1530 15 900 6.52 2.8 2547 720 1827 20 1200 5.60 2.4 2916 960 1956 25 1500 4.98 2.2 3242 1200 2042 30 1800 4.52 2.0 3531 1440 2091 35 2100 4.08 1.8 1 3719 1680 2039 40 2400 3.74 1.6 3896 1920 1976 45 2700 3.46 1.5 4054 2160 1894 50 3000 3.23 1.4 4205 2400 1805 55 3300 3.03 1.3 4340 2640 1700 60 3600 2.86 1.2 4468 2880 1588 65 1 3900 2.72 1.2 4604 3120 1484 70 4200 2.59 1.1 1 4721 3360 1361 75 4500 2.48 1.1 4843 3600 1243 80 4800 2.38 1.0 4958 3840 1118 85 5100 2.29 1.0 5069 4080 989 90 5400 2.21 1.0 5179 4320 859 95 5700 2.13 0.9 5269 4560 709 100 6000 2.06 0.9 5364 4800 564 105 6300 2.00 0.9 1 5468 5040 428 110 6600 1.94 0.8 5557 5280 277 115 6900 1.89 0.8 5660 5520 140 120 7200 1.84 0.8 5750 5760 -10 This FAA calculation was created to determine flow out of pond for HGL calculation Ids 1, 2, a:_ function as one pond. Please see Combined Pond FAA calculation for Detention Calculations. 1 8/18/2017 3:52 PM D:IProjects1146-011Drainage lDetention1146-011-Detention Pond I.x1sxIFAA_COFC idf Pond 1 I Schrader I 7 I Stage - Storage Calculation Project Number: 146-01 Project Location: Fort Collins Co Calculations By: S. Thomas Date: 8/18/2017 Pond No.: Pond 1 Required Volume Water Surface Elevation (WSE) Design Point Design Storm 100-yr Require Volume= 0.05 acft ft. Design Storm WQCV Required Volume= 0 ft, �ft. Contour Column Not Incremental Elevation (Y- Contour Area Depth Total Volume Total Volume Used Volume values) ft ft. ft ft ft acre-feet 4,975.60 0 0.00 0 0 0 0 4,975.80 2865 0.20 287 287 0.01 4,976.00 6659 0.20 952 1239 0.03 4,976.06 7979 0.06 439 1678 0.04 4,976.20 11382 0.14 1355 3033 0.07 ' This FAA c�i,oulatior, v✓�s crewed to de.cj.zx ow out of pond for HGL calculation for Storm A. Ponds 1, 2, arc will function as one pond. Please see Combined Pond FAA calculation for Detention Calculations. 1 I 1 1 1 1 t 1 1 ■� NORTHERN Schrader ENGINEERING Detention Pond Calculation I FAA Method Project Number: _=6-011 Project Location: Fort Collins, Colorado Calculations By: S. Thomas Date: 8/18/2017 Pond No.: Combined Pond 1, 2, and Input Variables Results Design Point n/a Design Storm 100-yr Developed "C" = 0.77 Approx. Area (A)= 0.8[ acres Max Release Rate = 0.' cfs Required Detention Volume WQCV 0 ft3 Quantity Detention 7837 ft3 (from FAA) Total Volume 0.18 ac-ft Time Time Ft.Collins 100-yr Intensity Qloo Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft) (ft) (ft ) 5 300 9.95 6.6 1977 39 1938 10 600 7.72 5.1 3067 78 2989 15 900 6.52 4.3 3886 117 3769 20 1200 5.60 3.7 4450 156 4294 25 1500 4.98 3.3 4947 195 4752 30 1800 4.52 3.0 5388 234 5154 35 2100 4.08 2.7 1 5674 273 5401 40 2400 3.74 2.5 5944 312 5632 45 2700 3.46 2.3 6186 351 5835 50 3000 3.23 2.1 6417 390 6027 55 3300 3.03 2.0 6621 429 6192 60 3600 2.86 1.9 6818 468 6350 65 3900 2.72 1.8 7025 507 6518 70 4200 2.59 1.7 1 7203 546 6657 75 4500 2.48 1.6 7390 585 6805 80 4800 2.38 1.6 7565 624 6941 85 5100 2.29 1.5 7734 663 7071 90 5400 2.21 1.5 7903 702 7201 95 5700 2.13 1.4 8040 741 7299 100 6000 2.06 1.4 8185 780 7405 105 6300 2.00 1.3 1 8344 819 7525 110 6600 1.94 1.3 8479 858 7621 115 6900 1.89 1.3 8636 897 7739 120 7200 1.84 1.2 8773 936 7837 8/18/2017 3:54 PM D:IProjects 1146-0111DrainagelDetention1146-011 Detention Pond 1 2 and3.x1sxlFAA CoFC idf Pond 1 I Schrader t t 1 1 1 I t 1 t 1 Stage - Storage Calculation Project Number: Project Location: Fort Collins Co Calculations By: S. Thomas Pond No.: Pond 1, 2 and 3 Combined Required Volume Date: 10/6/2017 Water Surface Elevation (WSE) Design Point Design Storm Require Volume= Design Storm Required Volume= acftft. W �ft. Contour Elevation (Y- values) Contour Area Depth Column Not Used Incremental Volume Total Volume Total Volume ft ft. ft ft ft acre-feet 4,973.40 225 0.00 0 0 0 0 4,973.60 663 0.20 85 85 0.00 4,973.80 1293 0.20 192 277 0.01 4,974.00 1503 0.20 279 556 0.01 4,974.20 1855 0.20 335 891 0.02 4,974.40 1991 0.20 384 1275 0.03 4,974.60 2132 0.20 412 1687 0.04 4,974.80 2277 0.20 440 2127 0.05 4,975.00 2426 0.20 470 2597 0.06 4,975.20 2518 0.20 494 3091 0.07 4,975.40 2646 0.20 516 3607 0.08 4,975.60 2039 0.20 467 4073 0.09 4,975.80 4973 0.20 679 4752 0.11 4,976.00 8837 0.20 1361 6114 0.14 4.976.20 13581 0.20 2223 8336 0.19 1 ' ■� NORTHERN ENGINEERING Schrader Propane Offices ' ORIFICE RATING CURVE Pond 3 100-yr Orifice Project: Schrader Date: 10/6/2017 By: S. Thomas Q = CdAo zgH Ao= Cd 29H 100-yr WSEL= 4976.16 Orifice Plate ' Outflow Q 0.13 cfs Orifice Coefficient Cd 0.65 ' Gravity Constant 100-year head g H 32.2 ft/s^2 2.91 ft Orifice Area Ao 0.01 ft"2 Orifice Area Ao 2.10 in^2 ' Radius r 0.8 in Diameter d 1.6 in Orifice Curve ' Stage (ft) H (ft) Q (cfs) SWMM Stage Note 4973.25 0.00 0.00 0.00 Pond Invert 4973.45 0.20 0.03 0.20 ' 4973.65 0.40 0.05 0.40 4973.85 0.60 0.06 0.60 4974.05 0.80 0.07 0.80 ' 4974.25 1.00 0.08 1.00 4974.45 1.20 0.08 1.20 4974.65 1.40 0.09 1.40 4974.85 1.60 0.10 1.60 4975.05 1.80 0.10 1.80 4975.25 2.00 0.11 2.00 4975.45 2.20 0.11 2.20 ' 4975.65 2.40 0.12 2.40 4975.85 2.60 0.12 2.60 ' 4976.05 4976.16 2.80 2.91 0.13 0.13 2.80 2.91 100-yr WSEL t 1 10/6/2017 2:37 PM D:lPM*ft11/6-0111Or8k89* Defenfb 0ffte S&011I6011_Offte Sae -Pond 3adBAOI liu S® LJ C 1 1 ■� NORTHERN Schrader ENGINEERING Detention Pond Calculation I FAA Method Project Number: Project Location: Fort Collins, Colorado Calculations By: S. Thomas Date: 4/3/2017 Pond No.: aond 4 Input Variables Results Design Point Design Storm lUu-yr Developed "C" = 0.93 Approx. Area (A)= 0.11 acres Max Release Rate = 0.08 cfs Required Detention Volume WQCV 0 ft3 Quantity Detention 789 ft3 (from FAA) Total Volume 0.02 ac-ft Time Time Ft. Col I i ns 100-yr Intensity Q100 Inflow (Runoff) Volume E(Release)lume Storage Detention Volume (mins) (secs) (in/hr) (cfs) (ft ) (ft ) 5 300 9.95 1.0 305 24 281 10 600 7.72 0.8 474 48 426 15 900 6.52 0.7 600 72 528 20 1200 5.60 0.6 687 96 591 25 1500 4.98 0.5 764 120 644 30 1800 4.52 0.5 832 144 688 35 2100 4.08 0.4 877 168 709 40 2400 3.74 0.4 918 192 726 45 2700 3.46 0.4 956 216 740 50 3000 3.23 0.3 991 240 751 55 3300 3.03 0.3 1023 264 759 60 3600 2.86 0.3 1053 288 765 65 3900 2.72 0.3 1 1085 312 773 70 4200 2.59 0.3 1113 336 777 75 4500 2.48 0.3 1142 360 782 80 4800 2.38 0.2 1169 384 785 85 5100 2.29 0.2 1195 408 787 90 5400 2.21 0.2 1221 432 789 95 5700 2.13 0.2 1242 456 786 100 6000 2.06 1 0.2 1264 480 784 105 6300 2.00 0.2 1289 504 785 110 6600 1.94 0.2 1310 528 782 115 6900 1.89 0.2 1334 552 782 120 7200 1.84 0.2 1355 576 1 779 4/3/2017 3:04 PM D:IProjects 1146-0111DrainagelDetention1146-011-Conceptual Detention Pond 4.xlsxIFAA _CoFC idf Pond 1 Schrader Stage - Storage Calculation Project Number: 146-011 Project Location: Fort Collins Co Calculations By: S. Thomas Pond No.: Pond 4 Required Volume Date: 4/3/2017 Water Surface Elevation (WSE) Design Point Design Storm i00-yr Require Volume= 788.85 ft3 Design Storm WQCV Required Volume= 0 ft3 �ft. �ft. Contour Elevation (Y- values) Contour Area FDepth Column Not Used Incremental Volume Total Volume Total Volume ft ft, ft ft ft acre-feet 4,974.20 190 0.00 0 0 0 0 4,974.40 529 0.20 69 69 0.00 4,974.60 833 0.20 135 204 0.00 4,974.80 1062 0.20 189 393 0.01 4,975.00 1210 0.20 227 620 0.01 4,975.20 1317 0.20 252 872 0.02 I ' (NORTHERN ENGINEERING ' ORIFICE RATING CURVE Pond 4 Orifice Q = CdAo z9H ' 100-yr Orifice Q Ao= Cd Project: Schrader 29H Date: 8/19/2017 By: M. Ruebel 100-yr WSEL= 4975.13 Orifice Plate ' Outflow Q 0.08 cfs Orifice Coefficient Cd 0.65 ' Gravity Constant g 100-year head H 32.2 ft/s^2 1.13 ft Orifice Area Ao 0.01 ft^2 Orifice Area Ao 2.08 inA2 ' Radius r 0.8 in Diameter d 1.6 in Orifice Curve Stage (ft) H (ft) Q (cfs) SWMM Stage Note 4974.00 0.00 0.00 0.00 Pond Invert 4974.10 0.10 0.02 0.10 4974.20 0.20 0.03 0.20 4974.30 0.30 0.04 0.30 4974.40 0.40 0.05 0.40 4974.50 0.50 0.05 0.50 4974.60 0.60 0.06 0.60 4974.70 0.70 0.06 0.70 4974.80 0.80 0.07 0.80 4974.90 0.90 0.07 0.90 4975.00 1.00 0.08 1.00 4975.13 1.13 0.08 1.13 100-yr WSEL Schrader Propane Offices 8/19/2017 2:43 PM C:1UserslSophanie0eskfop0minagelDetentionlOrfice Sue1146-011_Oeice Size -Pond 410nhce Size Il I., do i i I t J v `m my ° a A E o E 6 r C A 0 � � w L W v a E m 9 d N Y W Ti a °C v o d a . a Z T � a a y m P lE0 N _E R U O > LL Z• N d Y E y 'r 'c co m o m y � _ r E s 7 E vN � � w O E a E m � � u L 7 00 m v C V > v •~ L d C � u > m C cc2 aR (Lj a n L ~ vU lJ O d .^ LL 3 a v E O l� N O F O > v W cr K Y 7 > O z IV a U U 1 1 1 1 1 t NORTHERN ENGINEERING STORM TECH CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF Project Number 146-011 Project Name Schrader Propane Offices Project Location Fort Collins, Colorado Pond No : Basin Al-A2, B1-B3 Input Variables Results Design Point Basin A, B Design Storm WQ C = 0.64 Tc = 5.00 min A = 0.81 acres Max Release Rate = 0.37 cis Required Detention Volume 223 W 0.01 ac-ft Time (min) Ft Collins WQ Intensity (inlhr) Inflow Volume W Outflow Adjustment Factor Qe„ (cfs) Outflow Volume s (ft) Storage Volume ft3 5 1.425 222 1.00 0.37 ill ill 10 1.105 344 1.00 0.37 222 122 15 0.935 436 0.67 0.25 222 214 20 0.805 501 0.63 0.23 278 223 25 0.715 556 0.60 0.22 333 223 30 0.650 607 0.58 0.22 389 218 35 1 0.585 637 0.57 0.21 444 193 40 0.535 666 0.56 0.21 500 166 45 0.495 693 0.56 0.21 555 138 50 0.460 715 0.55 0.20 611 105 55 0.435 744 0.55 0.20 666 78 60 0.410 765 0.54 0.20 722 44 65 0.385 778 0.54 0.20 777 1 70 1 0.365 795 0.54 0.20 833 -38 75 0.345 805 0.53 0.20 888 -83 80 0.330 821 0.53 0.20 944 -122 85 0.315 833 0.53 0.20 999 -166 90 0.305 854 0.53 0.20 1055 -201 95 0.290 857 0.53 0.19 1110 -253 100 0.280 871 0.53 0.19 1166 -295 105 0.270 882 0.52 0.19 1221 -339 110 0.260 890 0.52 0.19 1277 -387 115 0.255 912 0.52 0.19 1332 -420 120 0.245 914 0.52 0.19 1388 -473 'Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2. Basin A and B WQ Chambers.xlsx ' Page 1 & 1 ' Project: Schrader Propane Offices - CO - 201479 ' Chamber Model - StormTech- SC-160 Units - impenai a �k He,a ror meo-m Number of chambers - 32 ' Voids in the stone (porosity) - 40 % Base of STONE Elevation - 4972.79 ft C Include Perimeter Stone in Calculations Amount of Stone Above Chambers - 6 in ' Amount of Stone Below Chambers - 6 in Area of system - 652 sf Min. Area - 474 sf min. area Height of Incremental Single Incremental Incremental Incremental Chl Cumulative System Chamber Total Chamber Stone I & St I Chamber Elevation ' (inches) (cubic feet) (cubic feet) (cubic feet) (cubic feet) I (cubic feet) (feet) 24 0.00 0.00 21.73 21.73 653.19 4974.79 23 0.00 0.00 21.73 21.73 631.46 4974.71 22 0.00 0.00 21.73 21.73 609.72 4974.62 ' 21 0.00 0.00 21.73 21.73 587.99 4974.54 20 0.00 0.00 21.73 21.73 566.26 4974.46 19 0.00 0.00 21.73 21.73 544.52 4974.37 ' 18 0.05 1.64 21.08 22.72 522.79 4974.29 17 0.13 4.30 20.01 24.31 500.07 4974.21 16 0.29 9.30 18.01 27.31 475.76 4974.12 15 0.44 14.14 16.08 30.22 448.45 4974.04 ' 14 0.54 17.25 14.83 32.09 418.23 4973.96 13 0.62 19.72 13.84 33.57 386.14 4973.87 12 0.68 21.78 13.02 34.80 352.57 4973.79 11 0.74 23.55 12.31 35.86 317.77 4973.71 ' 10 0.78 25.07 11.71 36.77 281.91 4973.62 9 0.82 26.40 11.17 37.57 245.13 4973.54 8 0.86 27.53 10.72 38.25 207.56 4973.46 7 0.89 28.63 10.28 38.91 169.31 4973.37 ' 6 0.00 0.00 21.73 21.73 130.40 4973.29 5 0.00 0.00 21.73 21.73 108.67 4973.21 4 0.00 0.00 21.73 21.73 86.93 4973,12 ' 3 0.00 0.00 21.73 21.73 65.20 4973.04 2 0.00 0.00 21.73 21.73 43.47 4972.96 1 0.00 0.00 21.73 21.73 21.73 4972.87 Weir Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 31® by Autodesk, Inc. Storm A WQCV Weir Rectangular Weir Crest = Sharp Bottom Length (ft) = 3.00 Total Depth (ft) = 1.00 'Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q ' Known Q (cfs) = 2.12 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Top Width (ft) epth (ft) Storm A WQCV Weir ' 2.00 1.50 1 ' 1.00 1 ' 0.50 0.00 ' -0.50 Friday, Aug 18 2017 = 0.36 = 2.120 = 1.07 = 1.99 = 3.00 Depth (ft) 2.00 1.50 1.00 0.50 1 1 11 -0.50 0 .5 1 1.5 2 2.5 3 3.5 4 ' weir W.S. Length (ft) Weir Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3138 by Autodesk, Inc. Storm B Water Quality Weir Rectangular Weir Crest = Sharp Bottom Length (ft) = 1.00 Total Depth (ft) = 2.00 'Calculations Weir Coeff. Cw = 3.33 Compute by: Known Q ' Known Q (cfs) = 0.57 1 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (fUs) Top Width (ft) Storm B Water Quality Weir Friday, Aug 18 2017 = 0.31 = 0.570 = 0.31 = 1.85 = 1.00 Depth (ft) 3.00 2.00 1.00 MI -1.00 0 .25 .5 .75 1 1.25 1.5 Weir W.S. 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However, what is known, is that the stage -discharge curves of the weir equation and the orifice equation will cross at a certain flow depth. The two curves can be found below: Stage - Discharge Curves 7.00 - 6.00 Weir Flow .... 5.00 - '- Orrfm now V m 4.00 - a+ r 3.00 V p 2.00- 1.00 0.00 . 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.60 Stage (ft) If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir. - - Input Parameters: Type of Grate: Neenah R-4370-27A Shape Rectangular Length of Grate (ft): 3.16 Width of Grate (ft): 3.16 Open Area of Grate (ft2): 2.40 Flowline Elevation (ft): 4976.290 Allowable Capacity: 50% Depth vs. Flow: Shallow Orifice Actual Elevation Weir Flow Flow Flow Depth Above Inlet (ft) (ft) (cfs) (cfs) (cfs) 0.00 4976.29 0.00 0.00 0.00 0.05 4976.34 0.21 1.44 0.21 0.10 4976.39 0.60 2.04 0.60 0.15 4976.44 1.10 2.50 1.10 0.20 4976.49 1.70 2.88 1.70 F Q100 0.25 4976.540 2.37 3.22 2.37 0.30 4976.59 3.12 3.53 3.12 0.35 4976.64 3.93 3.82 3.82 0.40 4976.69 4.80 4.08 4.08 0.45 4976.74 5.72 4.33 4.33 0.50 4976-790 6.70 4.56 4.56 Inlet at Design Point 2 is designed to intercept the full 1 00-yr flow of 1.33 cfs at the elevation 4976.46. INLET ON A CONTINUOUS GRADE Project: Schrader Intel ID: Daalgn Pt 7 - Inlet BS tr-Lo (C)-K FLwb H-Vert Design Information flneirt) MINOR "OR Type of Inlet Type - UW4)S lnad OomOMntlm ocal Depression (eddmoral to contnuous gutter oepreuion'e' fmm'O-NloV) tl o • 2.0 echee Total Number of Units in ttie Inlet (Grate or Cure Opening) No = 1 angle of a Single Unit Inlet (Grate or Curb Opening) L. 3.00 It idle of a Unit Greta (cannot be greater Nan W from O-M.) W. = 2.0D It logging Faaor for a Single Unit Grate (typical min. value = 0S) CrG = 0.60 0.60 �Iogptng Factor for a Single Unit Curb Opening (typic,al min, value = 0.1 Cr0 • 0.10 0.10 treat Hi,dniullcti OK - 0 < MINOR MMOR Inlet Intin-ce"m Capachy p 0.2 0.7 ah Ltal al Inlet tarry-OFlay (flow bypasaing Inlet) 4 •0.0 0. 1 are pture Paroantaga • QACk. - C%• 100 101 % Combo Inlet - Design R 3 osm, Inlet On Grade 8/1I1/2017, 4:26 PM NorthernEnaineerina-com // 970.221.41S9 INORTHERN ENGINEERING Schrader Propane Offices ' 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 existing and proposed storm inlets. Vehicle tracking control pads, spill ' containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. ' Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The 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. n 1 I� 1 Preliminary Erosion Control Report J 1 1 1 I NnrfilornFnnin**rinn.rnm // 07i1.771.11 SA {}»/§ ( {7%§\&°# - m- $ - � - °`0 ,- -! A2\�0 � a � �- §� ` §§ e s R k §2 (\/ §£ k � ■ � w §! u 2\>� \k \\ o �E �7E � M ! ! ■ E A m ))( !| We wvi U� �] LL- 00 w z « a 0 � a — - ---- -� ( ddv3OU.) m]�\ I 1 1 1 1 1 1 1 PROPOSED LID COMPUTATIONS Project: Schrader . Calculations By: S. Thomas Date: June 8, 2017 PROPOSED LID TREATED AREA LID BASIN NODE Basin(s) Area, A (sf) Percent Impervious Impervious Area, A (sf) LID1 Basin A 26,921 46% 12,460 Basin B 8,290 86% 7,125 Total Treated 35,211 56% 19,585 PROPOSED LID UNTREATED AREA LID BASIN NODE Basin(s) Area, A (sf) Percent Impervious Impervious Area, A (sf) LID2 C 2,383 5% 123 D 4,804 65% 3,146 UD1 2,181 21% 586 UD2 1137 0% 0 Total Proposed Untreated 11,105 35% 3,856 Stormtech Chambers - Basin LIM Basin A WQCV (ft) 352 Basin A Stormtech Chamber Volume (ft) 381 Basin B WQCV (W) 204 Basin B Stormtech Chamber Volume (ft) 205 Total Site Area (sf) 46,316 Total Proposed Impervious Area (sf) 23,441 75% Required Minimum Area to be Treated by LID 17,581 Total Treated Impervious Area (sf) 19,585 Percent Impervious Treated by LID measures 84% t t 1 1 1 1 1 I 1 NORTHERN APPENDIX E ENGINEERING REFERENCES NnrthornGnninrrinn.tnm // 070.771.A19R cis Y S z z 6 OT666" 006*" 068*" 0880660 OC806b0 09806" OS806" 0080600 OEB06" M.Mb .SOT i ID K � N e cn Z N O o _ m N m a ml0 c M O e z € Od P a x P Q e QQ m� m ,o N n C c s m to m m e � N c J ZQ zu -.a M.EE b oSOT I III 016060b 00606" 068060V OB806b0 OGB*" 09m" 0sm" 00806" OEB06W z 6� z in S z 0 � � � 0 z IL « � 0 z w 0 q & � 0 ) 2 CD\M(\ § cc «72; - 57/E / )E )00 E \ -0 0 £CL {C \ k)C E (c(\ J ))\7 ) Co r �4 §f /§=e @ §(E _ p i�/� ° \)( / )° \ \\§ 0 §w // !§g Q{i! I 3A \ /§Q E 34\ \ } § /} ƒ/, \kj \)�c� } {\ (kf) ,v! !Q/kp {) J` )ƒ� �G � 0E _ ,w;+; �§ (¥ ^ ! k|/ ) 3 \§kU 7 | g 7— )a 2CD /@ 2[f)) q - ® ®�� s a) M \ — #§ /k \ ~) {§ )§ &e®%§ £{ Z § I)))) )2 \/ }}(} )k /\j \{)¥) // 33 3/ AA (B$, \ \ \ ) } § 0 ` \ u S _ _ e k|rn _ g: §) < _ O O o Q( § i u & � � ma & ` ) \ � 7 k� 21 76- S t/ m {< $ 2 o o >« $, 2 o S:) { $ 2 « I\ n o O o ! V) - ( \� IHydrologic Soil Group—Larimer County Area, Colorado Schrader Propane Offices 1 1 1 1 1 73 Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644) Map unit symbol I Map unit name I Rating I Acres in AOI I Percent of A01 Nunn clay loam, 0 to 1 C percent slopes Totals for Area of Interest Description 1.61 100.0% 1.61 100.0% Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These ' consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. 1 1 Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6i6no16 Page 3 of 4 Hydrologic Soil Group—Lsrimer County Area, Colorado Schrader Propane Offices 1 n 1 Tie -break Rule: Higher qb� Natural Resources Web Soil Survey 6/6/2016 .� Conservation Service National Cooperative Soil Survey Page 4 of 4 No Text 1 1 1 1 1 NnrthernEnaineerina.<om It 970.221.4198 `\ I EVERGREEN PARK REPS T wLOT OT133BLOCK 3 / I / I / I I I I I / 1 / 4 / I I EVERGREEN PNiK REMT j I LOT 14, BLOCK 3 1 1 1 awoLeusMa3eraArem 1 It I I 1 I I / I I ixI'SNnr i 4 n+aSx.N I I o I I I 1 I/ IQ I / OWNERBURGER EerA3EBBAIrt I } LU I / a Jr i I LM3,IS IY]] I 3 JOB D NrrnEnI / / ♦ Bu'V r IPoILIR `1Y am AC 3 / \ 1 I r00,011 fIENCHORAIN D T 411111, j1 i , , 3 �Bu3nivl �1I EV RrGREEN PARK %_ _ awnvwa3 3ECONDREPLAT I I11 LOT I I 1 ao3oa3no+anow / _ I DETENPDrnt 1000ye r u3alAocoNa / 1a}VR EL: 4476.1e a � 1\ ��EM�J �n�• / / II `♦ 1 � � ti I I I/i 131 �1I1 M13 AC POND3 I II 'I loom gigg M � �1 am Acl ti 2 t / /--L06mwM[I_xK�te I I l l 11 0.0 ABC / awmxHa I 1— �/ anlBrsnK�Ka,� — I EVERGREEN PARK BvwvmSDe SECOND REPLAT LOT 2 1 — I ------------------ \ ! ------------------ I I I Iiw w0�°Mo I ww,aar I I /— — ,.--------- ---------------L__ I I I 1 1 1 1 I 1 1 I 1 1 — I \ i I / I / I / \ EVERGREENPPBRK 1 I REPLAN 1, LOT 3, BLOCK 4 11 wesD 1 If I l4 I II —� II I / li IT I I / I/ I II I EVERGREEN PARK I i REPLAT I, LOT 4BLOCK 4 I I omeH.leKan � I I > I I ^ i I LEGEND PROPOSEDOCINTGUIR vROPERTY wswa usxaw Dnxr ��.s�aw,•seswEen LOWPATH BawxraO xwxBLmB Iwo. DEBK:xvaxr Q NOTES: ,. .xE SRe ,rtP3.v10,00..iM 0, nLL KXBNN lME E 11E�B NE RE!INGNSIONIMIS TBHD,.H Dx,x530 DB,YnxDO UNIVERGROUNDUTUTPESINTHEARFACEMEWOOK, NEW CONSTRUCTROW THE CONTRACTOR _ eE RESYWSB3BLE TMir L� wxxwc, 9 .00i oN,...MES BYNIC HEMN w�Eei�„x`. wfrD rvOa.9eiol?HOW x �'iTT�tCi#F�r'f r7tIG7 OMINADE M,MMMY AB BKM ID TOTAL MMMe mind) 111 To Begin) 0 IeN 0100POINT wnis) 1 A O6t .9 S9 O.N AI)i BI D.13 .0 5.0 am Iy3 B3 0.N .0 £0 0.1 0.5C aN WC1WT 3 5.9 O.de AN5 D all .0 54 0]3 laUD BEd BLUE! OLS FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION Iwveeq , xcx •2DrEaT rxBDr xOLORADO RADaxcenMav is K,oe.CalltaIryou a9 Goy Of Iroft CDlllne, C1IO,'10C UTILITY PLAN APPROVAL wTROSEa ,y mv,� • D CHECKED BY. trab• BIWIy Mb Coff BV: W CHECKED BY: PMW A CHECKED BY: na CHECKED BT.