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HomeMy WebLinkAboutDrainage Reports - 09/21/2017II City of Ft. Collin raved, Plans Approved By Date Drainage Design Considerations for the Legacy Auto Final Development Plan (FDP) Fort Collins, Colorado June 21, 2017 Prepared for: Mr. Gary Farkas Legacy Tractor and Auto Sales 1845 N. College Avenue Fort Collins, Colorado 80524 Prepared by: Wohnrade Civil Engineers, Inc. 11582 Colony Row Broomfield, CO 80021 Phone: (720)259-0965, Fax: (720)259-1519 Project Number: 1707.00-LEG f Wohnrade Civil Engineers, Inc. 11582 Colony Row, Broomfield, CO 80021 Phone: 720-259-0965, Fax: 720-259-1519 1 ' June 21, 2017 Mr. Wes Lamarque Utilities Department City of Fort Collins ' 700 Wood Street Fort Collins, Colorado 80522 Re: Drainage Design Considerations for the Legacy Auto FDP Fort Collins, Colorado ' Dear Mr. Lamarque: Wohnrade Civil Engineers, Inc. (WCE) is pleased to resubmit this final hydrologic and ' hydraulic report for the Legacy Tractor and Auto Sales project for your review. We have addressed the first round of comments contained in the letter dated June 16, 2017. This report complies with technical criteria set forth in the City of Fort Collins, Stormwater ' Criteria Manual, and Urban Drainage and Flood Control District criteria. We acknowledge that the City of Fort Collins's review of this study is only for general conformance with submittal requirements, current design criteria, and standard engineering principles and practices. If you should have any questions or comments as you review this report, please feel free to contact me at your convenience. ,.\% Sincerely, Pp0 WOHNRADE Clu�lvgy �O;°.cn� 9LU 0. Mary B. Wohnra WE **T' tti ••������ Professional Engineer-(f,0;N�.,,11 0``` Drainage Design Considerations for Legacy Auto FDP ' Table of Contents 1. INTRODUCTION ........................................ ...................................................................................... 1 1.1 1.2 Objective.............................................................................................................................................1 Project History and Previous Studies..................................................................................................1 1.3 Mapping and Surveying.......................................................................................................................1 2. 2.1 SITE LOCATION AND DESCRIPTION........................................................................................ Site Location........................................................................................................................................1 1 2.1 Site Description...................................................................................................................................2 3. 3.1 PRE -PROJECT CONDITIONS........................................................................................................ Pre -Project Drainage Basins................................................................................................................2 2 3.2 Pre -Project Drainage Patterns.............................................................................................................2 4. POST -PROJECT CONDITIONS..................................................................................................... 2 4.1 Proposed Project Description..............................................................................................................2 4.2 Post -Project Drainage Basins...............................................................................................................3 ' 4.3 Post -Project Drainage Patterns...........................................................................................................3 4.4 Proposed Detention/Water Quality Pond...........................................................................................3 S. 5.1 DESIGN CRITERIA..........................................................................................................................4 Design References...............................................................................................................................4 5.2 Hydrologic Criteria...............................................................................................................................4 6. 6.1 EROSION CONTROL....................................................................................................................... 5 Erosion Control Plan............................................................................................................................5 6.2 Site Stabilization..................................................................................................................................5 7. CONCLUSIONS................................................................................................................................. 5 7.1 Compliance with Standards.................................................................................................................5 7.2 Variances.............................................................................................................................................6 8. REFERENCES....................................................................................................................................6 I 1 Drainage Design Considerations for Legacy Auto FDP TABLE OF CONTENTS, cont. Vicinity Map APPENDICES Appendix A: Post -Project Condition Hydrology Appendix B: Detention/Water Quality Pond Design ' DRAWINGS Sheet 1 of 2 Pre -Project Drainage Plan Sheet 2 of 2 Post -Project Drainage Plan 1 I a o N4*14 _ W Co Rd 56 EC09 "� u ECo Ptl:56- �i Pi E Z a nm ss U z 2 N C] N W Douglas Rd F Douglas Rd E Douglas Rd E � � c W Richards lakeF z c> a ` n R9PI ECT LOCATAON m T/118'45 North _ _— College Avenue Mountain ws z ze7 L ZZ U ry W � V _ecane a.e. — "'" Fort Collins W Mulberry sl .. a, ct E Mulberry S[ a c Arrowhead Colorado State r s� W EliLaoeth St University c Ss A LEGACY AUTO FDP / WONNRADEC/V/L ENGINEERS, INC. / Sheet i,sya cow> xo. VICINITY MAP I I I Drainage Design Considerations for Legacy Auto FDP Fort Collins, Colorado June 21, 2017 1. INTRODUCTION 1.1 Objective This study documents the results of a comprehensive hydrologic and hydraulic analysis for the proposed Legacy Tractor and Auto Sales FDP project located in Fort Collins, Colorado. The project includes a 10,500 sf building addition, new water and sewer services lines, site improvements, and an onsite stormwater detention/water quality pond (Photo 1). 1 1.2 Project History and Previous Studies Photo 1 — Project Site Looking Northeast There is one known hydrologic and hydraulic study for the Legacy Tractor property. A Final Drainage and Erosion Control Report for Legacy Auto was prepared by North Star Design as part of the Preliminary Development Plan, and is dated April 4, 2014. 1.3 Mapping and Surveying King Surveying, of Windsor, Colorado, provided field survey information and topographic mapping of the project site, with a contour interval of 1-foot. The survey was performed in January 2010, and was referenced to NGS Monuments U402 and V401 on the NAVD88 datum, and the NAD 83, Colorado State Plane (UTM Zone 13) North Zone survey coordinate system. 2. SITE LOCATION AND DESCRIPTION 2.1 Site Location The project is located in the Southeast 1/4 of Section 35, Township 8 North, and Range 69 West of the 6th Principal Meridian, City of Fort Collins, Larimer County, Colorado. The site is bounded by N. College Avenue on the east, the Larimer and Weld Canal on the north, and existing commercial properties on the west and south. The project is located outside of any FEMA regulated floodplain, as per the FEMA Flood Legacy Auto FDP Wohnrade Civil Engineers, Inc. June 21, 2017 Page 2 Insurance Rate Map(FIRM), Community -Panel Number 08069C-0977G, revised on June 17, 2008 (see Firmette). The property is also adjacent to a City of Fort Collins designated floodplain along the Larimer and Weld Canal. Floodplain mapping contained on the online mapping application FCMaps shows that this floodplain is contained within the banks of the Larimer and Weld Canal, and does not encroach onto the project site. 2.1 Site Description The project site is roughly 2.91 acres in size, and is located in a commercial area within the City of Fort Collins, Colorado. The site is partially developed on the east side of the property adjacent to N. College Avenue, and contains an existing structure with paved and gravel parking, and utilities. The existing site drains to a depression located in the southwest corner of the site, with no discernable outlet. The site is located in the Dry Creek Drainage Basin, as defined by the City of Fort Collins Master Drainage Plan. Stormwater runoff from offsite properties (0.68 acres) enters the site on the north, south and west. 3. PRE -PROJECT CONDITIONS 3.1 Pre -Project Drainage Basins The existing project site includes one single drainage basin, for a total area of 2.91 acres. ' 3.2 Pre -Project Drainage Patterns Stormwa ter runoff from the entire property drains overland, across paved and vegetated surfaces, to the existing depression located in the southwest corner of the property where stormwater is retained onsite. Runoff calculations for the pre -project condition have not been performed, since the maximum allowable developed release rate is a fixed 0.20 cfs/acre, and is independent of the historic discharges. 4. POST -PROJECT CONDITIONS ' 4.1 Proposed Project Description The proposed project includes a new 10,500 sf building addition, new asphalt parking and drives, new underground utilities, and a new onsite stormwater detention/water quality facility. t Legacy Auto FDP Wohnrade Civil Engineers, Inc. June 21, 2017 3 Page 3 The existing building will remain, but all other paving and utilities will be removed. 4.2 Post -Project Drainage Basins ' The proposed project site has been divided into 2 post -project drainage basins for a total drainage area of 2.91 acres. Post -project drainage basins and patterns will mimic pre -project conditions, with Basinl draining to the southwest corner of the property to the new detention facility, and Basin 2 draining to the existing depression, which is also located in the southwest corner of the property. 4.3 Post -Project Drainage Patterns Basins 1 (2.80 ac) drains overland in vertical curb and gutter and valley pans, at slopes ranging from 0.44% to 4.53%, to the new detention facility. The drainage pattern within this basins mimics pre -project drainage patterns. The 10 and 100-year peak ' discharges are estimated to be 6.9 cfs and 16.1 cfs respectively. Basin 2 (0.11 ac) drains overland across a native grass area to the existing depression located in the southwest corner of the property. The drainage pattern within this basins mimics pre -project drainage patterns. The 10 and 100-year peak discharges are estimated to be 0.2 cfs and 0.5 cfs respectively. Offsite Basins 01 and 03 will also drain to the new detention/water quality facility. Stormwater runoff from these basins will be conveyed by overland flow across vegetated surfaces. The 10 and 100-year peak inflow to the detention pond from Basins 1, 01, and 03 (3.28 ac) are estimated to be 3.7 cfs and 18.8 cfs respectively. Calculations made as part of this investigation, along with other supporting material, are contained in Appendix A. 4.4 Proposed Detention/Water Quality Pond The proposed detention/water quality pond is located in the southwest corner of the property, near the existing depression. The pond will detain stormwater runoff from 1 Basin 1 of the developed site, as well as, offsite Basins 01 and 03, which are located to the south and west of the property. The property lies within the Dry Creek Drainage Basin, which requires runoff from the 100-year developed storm to be released at a maximum rate of 0.20 cfs/ac. Stormwater runoff from onsite Basin 1, and offsite Basins 01 and 03 will be released at this rate. The maximum allowable release is 0.20 cfs/ac x 3.28 acres= 0.66 cfs. The computer program, Hydraflow Hydrogranhs Extension for AutoCAD Civil 3D 2016 was used to route the 100-year design storm through the detention pond. An inflow r Legacy Auto FDP Wohnrade Civil Engineers, Inc. June 21, 2017 4 Page 4 r hydrograph was developed to route the 100-year storm through the detention pond, which includes Basins 1, 01 and 03 (3.28 acres). Results of the pond routing predict a maximum 100-yr water surface elevation of 4982.79, with an associated storage requirement of 11,417 cu-ft. A 4" diameter orifice will control the release of developed stormwater runoff at a maximum rate of 0.47 cfs. The 100-year storm was routed through the pond, beginning at an elevation of 4982.00, which is the top of the Water Quality Capture Volume (WQCV). An emergency pond overflow weir has also been designed to pass the 100-year peak inflow (18.8 cfs) to the pond. The notch elevation of the weir will beset at an elevation of 4983.00, and will be 5' in width. The weir will direct stormwater runoff to the historic location, which is the existing depression in the southwest corner of the ' site, where it will be retained onsite. Extended detention has also been incorporated into the detention pond design. The computer programs, UD-Detention (v3.07) and UD-BMP (0.05), developed by the Urban Drainage and Flood Control District (UDFCD), have been used to calculate the required Water Quality Capture Volume (WQCV), and orifice size based on a 40-hour drain time. Based on the UD-Detention and UD_BMP spreadsheets, the calculated WQCV is 0.051 ac-ft, which, based on the pond stage -storage rating, translates to a water surface elevation of 4981.98, (or 4982.00), and design volume depth of 0.65'. The WQCV orifice plate will contain one column with 3- 7/16" diameters orifices. The pond outlet structure has been designed to mimic Figure OS-8 by Urban Drainage. Calculations made as part of this pond analysis, along with other supporting material, rare contained in Appendix B. S. DESIGN CRITERIA 5.1 Design References Drainage design criteria outlined in the City of Fort Collins Stormwater Criteria Manual (Reference 1), and the Urban Storm Drainage Criteria Manual by the Urban Drainage and Flood Control District (Reference 2), have been referenced in the preparation of ' this study. 5.2 Hydrologic Criteria ' Due to the relatively small basin size, and in keeping with criteria set forth in the City of Fort Collins, Stormwater Criteria Manual, the Rational Method has been used to estimate peak stormwater runoff from the project site. i r I Legacy Auto FDP Wohnrade Civil Engineers, Inc. June 21, 2017 5 Page 5 The initial 2 and 10-year, and major 100-year design storms have been used to evaluate the proposed drainage system. Rainfall intensity data for the Rational Method has been taken from IDF equations generated specifically for the project site using the Y Hydraflow Hydrographs Extension computer software from Autodesk. Point ' precipitation frequency estimates were generated using the NOAA Atlas 14, Precipitation Data Frequency Server, which are site specific. ' 6. EROSION CONTROL 6.1 Erosion Control Plan A proposed rainfall erosion control plan during construction will consist of temporary structural erosion control measures. Erosion control measures have been specified on the Grading and Erosion Control Plan, and on three separate drawings contained in the written Stormwater Management Plan (SWMP). These drawings include a Pre -disturbance, Interim, and Final Stabilization Plans. Based on requirements set forth in the 2014 Preliminary Development Plan, Low Impact Development (LID) design criteria will not be required for this project. i Wohnrade Civil Engineers, Inc. has prepared a separate report containing the Stormwater Management Plan (SWMP) for this project. A Colorado Discharge Permit System (CDPS), Stormwater Discharge Associated with Construction Activities application has also been submitted to the Colorado Department of Public Health and Environment. A City of Fort Collins Erosion and Sediment Control Escrow/Security Calculation has been prepared for this project, and is included in the written SWMP report. 6.2 Site Stabilization All areas disturbed by construction will be landscaped, paved, or re -seeded using the recommended seed varieties, quantities, and application rates as specified on the project Landscape Plan. 7. CONCLUSIONS 7.1 Compliance with Standards The proposed drainage improvements been designed to comply with all applicable ' drainage criteria, in accordance with the City of Fort Collins Stormwater Criteria Manual. I I 1 1 1 1 1 1 Legacy Auto FDP June 21, 2017 Page 6 Wohnrade Civil Engineers, Inc. 7.2 Variances There are no variances requested as part of this stormwater drainage design. 8. REFERENCES 1. Stormwater Criteria Manual. City of Fort Collins, adopted December 2011. 2. Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, Denver, Colorado, Revised April 2008. 3. CDOT Drainage Design Manual, Colorado Department of Transportation. 4. Geotechnical Investigation, Proposed Detention Pond. CTL Thompson, Inc., January 29, 2015. w mb w �BW w�� =®ova W C 1 8 i W W g u E m n o E QLL o Q a 0- oo dig 2e E' °C' o'oct1 g °g zm a "� IL LU z°+ °8mti >y CLi z 20 S r ocz A li! i O Fy • p m O LL F W F n E ^ m h � Bo Ly o Z O oog° S nEgoo 4 0 z'• 3 w m m°� ° W ¢ U 0 sE`, Est` J L O C Q CO) � z C LL wa ! F " E cmc n-w IL W � r� �g i11/ c 47 2] uLL M U o z o N O Li 2 w ~� mgz`� Li 'o2Ec d _C U. o $ _ m c w z X J w W w N z O m O 0 w N w J �Y N to O z m o_ a U QLU cn J J H J O U o Z x a Q OJ 4 X b x 0 J J cn t 11 i I I I Appendix A Legacy Auto Final Development Plan (FDP) May 10, 2017 Page 1 of 3 Wohnrade Civil Engineers, Inc. Composite Percentage Imperviousness Calculations: Post -Project Condition, Basin 1 NRCS Soil Tvne D Surface Characteristics Streets: Paved Streets: Gravel Drives and Walks Roofs Lawns Clayey Soil Imperviousness Area (acres) 0.000 0.000 1.070 0.240 1.49 0.43 Percent Imperviousness 100 40 90 90 2 Correction Factors K. and K,p for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0.000 0.067 0.132 0.209 0.258 0.292 A 0.000 0.055 0.110 0.158 0.185 0.212 Equations RO-6 and RO-7, Drainage Criteria Manual, Volume 1 C, 0.21 0.26 0.32 0.37 0.39 0.42 C, 0.25 0.31 0.37 0.44 0.47 0.50 Cm 0.30 0.36 0.43 0.51 0.55 0.59 Equations taken from Urban Storm Drainage Criteria Manual, Volume 1, Chapter 5, Section 2.7, by the Urban Drainage and Flood Control District, Denver, Colorado Post -Project Condition, Basin 2 NRCS Soil Tvne D Surface Characteristics Streets: Paved Streets: Gravel Walks and Patios Roofs Lawns Clayey Soil Imperviousness Area (acres) 0 0.00 0.00 0.00 0.11 0.02 Percent Imperviousness 100 40 96 90 2 Correction Factors Kq and K, for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0.000 0.108 0.206 0.324 0.393 0.452 A 0.000 0.088 0.167 0.236 0.276 0.315 Equations RO-6 and RO-T Drainage Criteria Manual, Volume 1 Cp 0.00 -0.01 0.07 0.14 0.18 0.22 Ca 0.03 0.08 0.17 0.26 0.31 0.36 Con 0.06 0.16 0.26 0.38 0,45 osi S:\PROJECTS\LEG\DRNG\LEG-DevC.wpd Legacy Auto Final Development Plan (FDP) May 10, 2017 Page 2 of 3 Post -Project Condition, Basin 01 NRCS Soil TvnP_ D Wohnrade Civil Engineers, Inc. Surface Characteristics Streets: Paved Streets: Gravel Walks and Parking Roofs Lawns Clayey Soil Imperviousness Area (acres) 0 0.00 0.00 0.05 0.28 0.15 Percent Imperviousness 100 40 90 90 2 Correction Factors K, and K., for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0.000 0.095 0.182 0,287 0.349 0.400 A 0.000 0,078 0.149 0.211 0.246 0.282 Equations RO-6 and RO-7, Drainage Criteria Manual, Volume 1 CA 0.02 0.10 0.17 0.24 0.27 0.31 C, 0.08 0.17 0.25 0.33 0.38 0.43 Cm El 0.14 0.24 0.33 0.43 0.49 0.54 Equations taken from Urban Storm Drainage Criteria Manual, Volume 1, Chapter 5, Section 2.7, by the Urban Drainage and Flood Control District, Denver, Colorado Post -Project Condition, Basin 02 NRC..nil Tvne D Surface Characteristics Streets: Paved Streets: Gravel Walks and Parking Roofs Lawns Clayey Soil Imperviousness Area (acres) 0 0.00 0.00 0.09 0.11 0.42 Percent Imperviousness 100 40 90 90 2 Correction Factors Kq and K,o for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0.000 0.068 0.135 0.214 0.263 0.298 A 0.000 0.057 0.112 0.161 0.188 0.216 Equations RO-6 and RO-71 Drainage Criteria Manual, Volume 1 CA 0.20 0.25 0.31 0.36 0.39 0.41 C, 0.24 0.31 0.37 0.43 0.47 0.50 COD 0.29 0.36 0.42 0.50 0.55 0,59 S:\PROJECTS\LEG\DRNG\LEG-DevC.wpd Legacy Auto Final Development Plan (FDP) May 10, 2017 Page 3 of 3 Post -Project Condition, Basin 03 NRC'.0 Cnil Tvna n Wohnrade Civil Engineers, Inc. Surface Characteristics Streets: Paved Streets: Gravel Walks and Parking Roofs Lawns Clayey Soil 1MPW+iWW**8 Area (acres) 0 0.00 0.00 0.15 0.00 0:so Percent Imperviousness 100 40 90 90 2 Correction Factors Kp and K,, for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0.000 0.020 0.048 0.078 0.103 0.109 A 0.000 0.018 0.044 0.069 0.082 0.095 Equations RO-6 and RO-7, Drainage Criteria Manual, Volume 1 Ca 0.69 0.71 0.73 0.76 0.77 0.79 C, 0.71 0.73 0.75 0.78 0.80 0.81 CCD 0.73 0.75 0.77 0.80 0.83 0.83 Equations taken from Urban Storm Drainage Criteria Manual, Volume 1, Chapter 5, Section 2.7, by the Urban Drainage and Flood Control District, Denver, Colorado Post -Project Condition, Basins 1, 01 and 03 NRC1; gnil Tvna In Surface Characteristics Streets: Paved Streets: Gravel Drives and Walks Roofs Lawns Clayey Soil Mnpewim0arress Area (acres) 0.000 0.000 1.070 0.440 1.77 0.43 Percent Imperviousness 100 40 90 90 2 . Correction Factors K. and Kip for Use With Equations RO-6 and RO-7 NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0,000 0.067 0.133 0.211 0.260 0.294 A 0.000 0.056 0.110 0.159 0.186 0.214 Equations RO-6 and RO-7, Drainage Criteria Manual, Volume 1 C, 0.20 0.26 0.31 0.36 0.39 0.42 Cp 0.25 0.31 0.37 0.43 0.47 0.50 CCDEJ 0.29 0.36 0.43 0.50 0.55 0.59 S:\PROJECTS\LEG\DRNG\LEG-DevC.wpd I I C E I I I 1 I I 0 O V LL v O O O O N TL � m N tO O p O t0 T F eda co 0 � o o o 0 p 0 p 0 o 0 0 0 Q O > n o 0 o 00 0 p op m O T m 0 0 0 > q) O J C 'ca O Ql Qo O O O O O O C U ._ 0 0 0 0 0 0 U � N O N U a o ma p O p 0 0 0 cJ c m o 0 0 o m '^ r El o o c o c O O a 10 p O O O m ,v m O m 6 A o_ u a N O O O N rl O (7 O= O O O O T U � N o U � L _ m O m o o a 0 p 0 p o p m O Q rn L. IL U h >✓ O � o� o 0 m 0 N 0 o 0 0 1 0 0 N LL = >. Y_ O C o 0 0 0 0 0 Y c N O —a n o = N n N E O C i Q m u o 0 0 0 0 0 m O O T O O U 0 C O m l7 N N �c 0 �C) Eon ooU)E EoU U QJ N o 0 O y U O O O O O O O O O O O cn EQF i U -le Y U o T m�a�f o LL T CV \ v/ V O i /C7 W N m N _ O N O O O a III LL CM (n cc) «T ">- C r- 0 W Y Y _Oa) CU = N l7 ()OF-C7F-F- C>CC a 3 I L I I i I I r I I 7 OH LL V OI N f0 N m 4% o o m a o 0 -O (Tja m m m c LL O O T Q C) .. N T Q o 0 0 o 0 0 0 0 0 �Vx O 0 C Q) O J� _0 N U •p N _ <d O «1 L J O O O O O N }+ }`+v p O 4 � lA N O O O O O O O O fV m Tpi p > V) Q O Q o f g a= O o 0 Uo o T N U y� _ m N C O O N N O O CD L � N I � O O O N m= J CI t7 N O 1� U C � �Of p Y V -V P N O n P (o N Oc r Vo U CO gyp\ � ` U V ¢ 0 m N < YI m N -p C �� W ^` 0)A � (j m O c 1L Q N N O O C1 6 U) V O O d N O q O O o O+ Q UI E J ?, C� �n0 N Ili O u U_o� O LL T 3 o� Q m N O O O o L 0) CO (D + H Fa CKS c)L \ C p i p J I- C U O W �� � �i *-' > II II II O CUOF-C7hl- c>� w C oa o N 0 (7 0 IL NIZ6 0 N d A a I I I I I 11 r I r LL v _r c — d m m � �a ,= o a o o a o Q T O T •• � N _o a o 0 0 0 0 0 V CD co IQ T > > c y 2 v U .W Y7 N N � Rf U d❑ 7E6- 0 0 0 60 m o 0 0 0 0 ♦/� O � E c o c c � }I � ` v >_ A Q N O O O O d ^ m 1.i O IL > N CD T Q o N O O O O U U + o m \ O L. IL U } U O I z ¢ n `° Y o o 0 0 0 0 0 0 0 0 0 0 � O r O LL U L n N n n m C O U o d o o a O Ry O E O L o Q V m O � O d O m O n O m O (d Ql O T � U ' C C M U chi Cj C O U N CIi �C)m cLL a n N 1H ° U � o o N L �oA m y C O O O O O O 3 c c � Y U ro o� N If T \ > C = No CI O o LL c am U) co + Id III C? L \ N C O 4l O U J~ C 0 0 !� > II II III N ttl U01—C7H1— —C:>cC 0,- m �a f N O O o G m 0 11 I I I` Table 6-3. Recommended percentage imperviousness values Land Use or Surface Characteristics Percentage Imperviousness (%) Business: Downtown Areas 95 Suburban Areas 75 Residential lots (lot area only): Single-family 2.5 acres or larger 12 0.75 — 2.5 acres 20 0.25 — 0.75 acres 30 0.25 acres or less 45 Apartments 75 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 10 Playgrounds 25 Schools 55 Railroad yard areas 50 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off -site flow analysis (when land use not defined 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 2 Lawns, clayey soil 2 6-8 Urban Drainage and Flood Control District March 2017 Urban Storm Drainage Criteria Manual Volume 1 [I .50 mum ME ME WIN mqmm No ism Bps a so .10 win5 man 0 m .06 m 0 0 = .04 3 00 an mm�mmo� .02 .01 0051 2 4 6 10 20 Average vellwhy (ftleec) EQUATION FOR FIGURE 3-1: PAVED: V=20.3282(s)0.5 (210-WT-64SecondEd..June1986) UNPAVED: V= 1 6.1345(sf-5 s= slope in ft/ft ' Pro act. LEG 1707.00 Dote: Q5„7117 Scale: NA Designed By: NA t iAl��t�lri4./.1f i��ra�wl�a �� �a�� Wnili�■ �i m n i mnri� �� ■�NNNn! i�iii�iii i vnn�n :ate nN _ ���11111��■ ��l�illllv�8� FIGURE 3-1 AVERAGE VELOCITIES FOR SHALLOW CONCENTRATED FLOW W0NNRe40E CIVIL ENGINEERS, INC „582 DaWay Row � BioomrroM, coa.oa, boas, PAone: (770)159-0965, Fmr (770)159-1519 1 Sheet Sheets I I I I I I 4r29/2017 Precipitation Frequency Data Server l) NOAA Atlas 14, Volume 8, Version 2 Location name: Fort Collins, Colorado, USA* Latitude: 40.6121°, Longitude:-105.0761 & Elevation: 4991.38 ft" NO a 'source: Maps - "source:e: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sonja Perim, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOAA, National Weather Service, Silver Spring, Maryland PF tabular i PF graphical i Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Average recurrence interval (years) ration F 1 ���������� 2 5 10 25 50 100 200 500 1000 0.263 0.311 0A10 0.513 0.686 0.843 1.02 1.22 1.52 7F 1.78 5711in (0.209-0.327) (0.247-0.386) (0.3250.511) (0.404-0.643) (0.534-0.927)11(0.633-1.14) (0.737-1.41) (0.842-1.74) (1.00.2.21) (1.13-2.58) 10min (0.307-0479 0.36 -0566 0.750749) (0. 9-0.941) (0.7801.36)11(0.927-1.67) (1.08..07 : (13.2.54 1.473324) 16 5377 15-fllln 0.74-0584 0.44-0690 (0.579.0913) (0.0911.15) 1(0.954-11.66) (1.132.04) (1.318253) (1.%3.10) l(179-3.96)(2.01-4.60 0.606 0.715 0.945 1.18 1.59 1.95 2.37 2.84 3.55 4.14 30{rlin (0.482-0.752 0.568-0.889) 0.747-1.18) 0.931-1.48 (1.24-2.15) (1.47-2.65) (1.71-3.28) (1.96-4.03) 1(2.33-5.15) (2.62.6.00 1.47 60 Rlin 0.589-0 919 0. 93-1.08 0.917-11.45 1.15 83 1.55 2970 1: 6-3.36 2: 8.4.19 2.515519 3. 256.67 3.41 7880 2a,r D. 00 1508 0.822--13.27 1: 9- .70 1.38-2.17 1. 8 3923 2.26 4.03 2.675A6 3: 0-6.29 3758.14 4.24 9354 0.967 1.13 1.51 1.92 2.64 3.31 4.09 4.98 6.32 7.46 3fir 0.776-1.18 0.908-1.39) 1.21-1.85) (1.53-2.37 (2.10-3.56) 3.00-5.63 (3.49-7.02)11(4.239.11) (4.80-10.7) 1.15 1.35 1.79 2.26 3.07 3.81 4.67 5.66 7.13 8.37 6fir (D.927-1.39) (1.09-1.63) (1.442.17) (1.802.76) (2.44-4.08) (2.93-5.08 ) ( 3.456.36 ) ( 3.99.7.89 ) ( 4.82.10.2) (5.4411.9) 1. 2.1 12 hr 1.131..67 1.32--61395) 1.2.12.54) 2. 063.16 2.74� 9 3. 3.5.49) 3. 406.77 (4.2708.28)11(5.06-10.5) (5.67-612.2 4.2 827 24hr 1.38-2.00 1.59-2.31 2.01 2794) (2. 293.58 3. 88 .94 3. 865.97) 4: 0- (4.62 8580 5. 251.1) (6.0308.8) 1.91 2.27 2.94 3.55 4.49 5.28 6.15 7.09 8.44 9.53 2 day (1.57 2.25) J111.87-2.68 2.41-3.46) (2.894.21) (3.58-5.63) 4.10-6.71) (4.61-8.02) (5.10-9.53) (5.84-11.7) (6.40-13.3 3tlay �10.42 .15 , 2: 3-2587 259-3.69 3: 0.4.46 3. 05592 4.3457.02 4: 6-8.36 5.36-9.90 6: 0. 2.1) 6.67-813.7 4 day 1.82 2056 2: 5-302 27 33.87 3.25 4665 3. 8 6514 4. 3-7..27 5: 56.63 5.56-0.2 6.33- 2.4 6.90-14.1 2.51 2.97 3.78 4.50 7F 5.57 6.45 7F 8.397day 79 109 .39 (2.09-2.90) (2.47-3.43) (3.134.38) (3.71-5.24) 1 (4.48-6.82) 1(5.07-8.02) (5.62-9.44) (6.1311.1) ](6.89-13.3) (7.47-15.1 10day 23.20 2753.79 3.474 81 4.09-5.72 4.88-7.35 5.48 8.58 6.03 10.0 6.549 1.7 7.29 14.0 7.85 5.7 5. IF 12.4 20tlay 2.9 3: 3-4.09 3.51 4875 4.31-15.86 4.97 6684 5.77 8352 : 68.9.79 6.91.0111.3 7: 8. 8.08. 5.2 8.60- 6.9 30day (36 04.80 4: 3 5.53 5: 0.6.74) 5.761-87 78 6. 3 9553 7. 5--010.8) 76 8-12.4 8. 2014.1 8.78 6.3) (9.28 8.0 5. 45�ay 4.2705.66 4.91 6051 59 37.91 6.749.08 7.62311.0 8.28 2.4 8.81' 14.0 9: 4 5.8 9.86- 8.1 10.3 9.8 6.57 60 day 4.82 6834 558-7.35 676-8.96 7. 8.10.3 8.65-12.4 9.37- 3.9 9.93.15.7 1 .4 167.6 1L 19.9 11.4621.7 t Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precoitabon frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. ttlacKto IDD PF graphical ' http:/Thdsc.nws.noaa.gov/hdsc/pfds/pfdsj3rintpage.html?lat=40.61218Jon=-105.O768&data=depth&units=english&series=pds 1/4 I4/29/2017 Precipitation Frequency Data Server PDS-based: depth -duration -frequency (DDE.) curves Latitude: 40:6121", I.nngitude:-105',U76$` 18:.I 1 9 T I I I I I I , 16' "• - 14 12 a v,10 t C (" IL Z, OC' •. E ?.m' . J. T A E 'E E E` _ L L: _ t, m �Tm m m A A mt m T'>. m m. 111. O ^ N.in ;p N! M D Duration ..18. 14 ._._... ....... . y 8.. J� (L ". _ 21 01. 2 5 16 .25 50100 200 500 1000 Adefage recuirence'inteNat (years) NOAA Atlas,14. Volume 8, Vemion.2'. Created (GMT)'. Sat Apr 29 16:41.27 2017 Back to Too Maps & aerials Small scale terrain 1+ Averagerecunence interval (Yew) — 1 2. — 5 10 25 s0 — 100 — 200 560 1000 Duration — 5-min — 2-day — t0-min — 3-day — 15-min — 4-day — 30-min — 7-day — 60iNn — 10-day — 2fir — 20-day — 3fir — 30-day — 8fir — 45-day — 12-tr — 50-day — 24fir http://hdsc.nws.noaa.gowhdsc/pfds/pfds jxintpage.htm l?lat--40.6121 &Jon=-105.0768&data=depth&units=english&series=pds 24 4/2912017 Precipitation Frequency Data Server .r, 50E :rnulli � Ln ,,If _u' U.Gkm i' '-alka ,i 0.4n, Large scale terrain Terry Sze 52E -- Lake fioncc) l r + r. ynC 2 2krr L Large scale map 1� (a ' Cb enne�� 44rtji ao reft I Qom; CAnprtgM ' Boulder _yUe/rya 100km 0mi Large scale aerial httpi//hdsc.ryws.noa&gov/hdscipfds/pfds_printpage.htm 17lat=40.6121 &Ion=- 105.0768&data=depth&units=engli sh&series=pds 3/4 4✓29/2017 Precipitation Frequency Data Server Back to Too US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions(&noaa.aov Disclaimer http://hdsc.nws.noaagov/hdsc/pfds/pfds_printpage.html?Iat=40.6121&lon=-105.0768&data=depth&units=english&series=pds 4/4 I Hydraflow Rainfall Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. 00.5 Return Period Intensity -Duration -Frequency Equation Coefficients (FHA) (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 - 2 29.9744 10.7000 0.8283 - 3 0.0000 0.0000 0.0000 - 5 50.0131 10.7000 0.8283 - 10 65.2885 10.7000 " 0.8283 -- 25 82.5349 10.7000 0.8283 -- 50 97.3175 10.7000 0.8283 - 100 110.4577 10.7000 0.8283 - File name: LEG.IDF Intensity = B / (Tc + D)"E Saturday, 05 / 6 / 2017 Return Period Intensity Values (in/hr) (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 3.06 2.44 2.04 1.76 1.55 1.39 1.26 1.16 1.07 1.00 0.94 0.88 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 5.11 4.06 3.40 2.93 2.59 2.32 2.11 1.94 1.79 1.67 1.56 1.47 10 6.67 5.31 4.44 3.83 3.38 3.03 2.75 2.53 2.34 2.18 2.04 1.92 25 8.43 6.71 5.61 4.84 4.27 3.83 3.48 3.19 2.95 2.75 2.58 2.42 50 9.94 7.91 6.61 5.71 5.04 4.52 4.10 3.77 3.48 3.24 3.04 2.86 100 11.29 8.98 7.50 6.48 5.72 5.13 4.66 4.27 3.95 3.68 3.45 3.25 Tc = time in minutes. Values may exceed 60. 0--;- lle OADDlI In uvdmnn.0 D�inf�ll nnln nnn Storm Rainfall Precipitation Table (in) Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 0.00 1.78 0.00 2.28 4.25 5.77 6.80 4.63 SCS 6-Hr 0.00 1.23 0.00 1.61 2.60 0.00 0.00 3.76 Huff -1st 0.00 0.00 0.00 0.00 4.00 5.38 6.50 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 3.90 5.25 6.00 0.00 40° 36:47 N Q- 3 41' N a Hydrologic Soil Group—Larimer County Area, Colorado 8 (Soil Mapping) 493410 483400 4834M 453470 493480 3 Map Scale: 1:8351 printed on A portralt (8.5" x 11") sheet Meters N 0 10 20 40 W A Fee[ 0 40 W i W 240 Map projedJon: Web Mercator Comer coordinates: WGS84 Edge tics: UtM Zone 13N WGS84 l SD Natural Resources Web Soil Survey -91111111111 Conservation Service National Cooperative Soil Survey 4a^ 3s 47rN T +i z 2 48 W 41' N 40510 4M= 3 to O 0 4/29/2017 Page 1 of 4 0 z W 0 W J IL N 0 N ((Opp « N N y m 0 ` y M -Q y N I 3 c 0 O 10 U 0 O O U O w C c v u A m o E d c v y E = N yE a 0 5 E cNi N °y n o Q 0- `° 0 uri L m cn m U1 �yQ m c y L rI O « Q « J y `� m C E m O1 0 C aw2Dm Z UN Y� cLiE�a �yo �c«m m 0 4. �c a�5m < o 3�mo O wn 3 E U w m m O ca c Q HmL o m o L �onym D Qm W m O�QT v_ a°1i y« o c> c o y �� c- c E —aoi 0' 0 0 E n m w y a N L O W af O o U 0— U U O Ul N a N M n O T y O m N O U T N 0 y 'L' E O .�.. J (n y n C y f0 - J> a y L C O i0 E m n o N N EmP„ a N Q' Z;v a v Q U C LM M N N mm �� f0 Ul CD o N 0 0m0, � E aTi oc'co c� n2� �m`Pu `—'c Q`� �m `0v am 32 `o=cn m �o "o m Env �0 00, c TEom� o 0 yp m y Ee mJ ati NW O D v ° w y n.60W m w« En -C' vN o.ny E mF5 L F- C y C O U W E— U y N N d E p N p (n zi U l0 O y U i a v Q 10 L h- O '0 j (n (n 'p N (n l0 ap O N L 0@ L F U E y a m 1 N e c m m T C N U c w T t n �° L O O m m O E m o 0! p L n m w o 0 U U 'o 0 Z w ; 0 O K J Q a o■■ a F i 1 u m■ o a v d Q m o m s d v e s < a °a_ o 0 o 0 a 0 0 u a° o 0 0 a m u o 0 z o 0 a m o c � � o Z y o -M a m m �< �Q m c� „Q m �Q o a : o.... m .o❑❑■■❑0011 0 y y N Q N r V m z O� i [1 Hydrologic Soil Group—Larimer County Area, Colorado Hydrologic Soil Group Soil Mapping H g' drolo is Soil Grou a y p-Summaryby ri r ` ' u w Map Unit Lanmer County Area ,Colorado (C0644)i Map unit symbol Map unit name *' Rating � `: � a - Acres FNercent of AOI 22 Caruso Gay loam, 0 to 1 percent slope D 1.8 63.5% 73 Nunn clay loam, 0 to 1 percent slopes C 1.1 36.5% Totals for Area of Interest 2.9 100.0% Description 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. 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. ' USDA, Natural Resources Web Soil Survey � Conservation Service National Cooperative Soil Survey 4/29/2017 Page 3 of 4 Hydrologic Soil Group—Larimer County Area, Colorado Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie -break Rule: Higher Soil Mapping USDA Natural Resources Web Soil Survey 4/2912017 Conservation Service National Cooperative Soil Survey Page 4 of 4 [l 1 1 i 1 1 1 1 1 1 1 Appendix B 1 •ri n Nrnrnoon ++ i-+ a ei a M Q N m oo to a w c-I c-1 H c•I oo M N LO 0J 4- m 00 m N r4 M m N m N H N m M 0 ON n r-I E V r-1 LM 00 M It Lf1 m • M M m w 01 7 7 -r-I m It 00 01 In • N N N m m W 00 00 V N 00 Ln m N ID r-I w N E r-I C 3 m N fn • 0) w N rn Ln w N Ln N M ID -* M M M W LT H 00 W M r-I 7 O O V • 00 N N Q r-1 Ln w M 00 �* r-I N ei 00 Ln N LT w M m m r-1 N M U> U m m rn H Ln H N-* w 01 r-I r-I N M en :3 Ln Ln W N N 00 0) a-1 H H ei H ri LO C � N i-+ E E 4- m o m m M LM M H M W 00 M N N rl Ln m LO N m� m L. 7 -r-I Q � � L,0 M � � � � M Ln 00 r-I M 00 L!1 M N N -two � m n V M V r-I C 7 Q N r-I • W rl e-1 1� M e-1 M OL N N 01 10 M m I� lA N m n l!1 M c O O V \I • Ln 00 N ri N rn t-1 M 0) m w w N 00 00 m m H ei N M-t -* Ln w H> V v Z m M r-I Ln N r♦ ri N rn M a 0 w w w w w w n N N N n n N N n Lll {a C N r-iM m m M M m I� 00 L. OL to L0 0J w 4- m M N Ln N e-. In L+. LL. DO n N L. 0. N 1D (n M m M N W W x ri E Ln M t0 LO L. O. N N m w 1 }+ 7 N m o m 00 I* M n n m M n N n m N LO to m • m E ri 7 E a% N ri LO n m ri W LO rn r-I N e-. • rn m N 01 r-iN n Z w n Ln 00 Ln N 0) 7 O> V > . 00 r-I N N Ln n M 00 In ci 00 Ln N L0 ON m m L-1 N rn m m M N CA OJ lJ > Q v N N M N r-I m m N LO ei N Q 10 01 ei r-I N M M Lf1 L!1 LO n n 00 01 a -I ei ei r-I r-I O1 oC I ri Ly Lo on 4J.I Lo c c v L.4 J ai C i-+ 07 O E CL)E Lu 4- E 00 V V n m r-Im Ln N r-IW LD M m ON 01 00 L M 0. OL N H m N N N n e-. M 00 Ln M N N Q l. m W w Q M Ln 7 N N-* Ln N . . . 0. L V r-1 00 7 Q N a1 . N e-I w N 00 It N M 0) Ln N 01 w M m N L!1 N m n Ln M LL c O> V \ W 01 rn r-I N M rl M OL m LO W N 00 00 OL m r-I r-I N M V V Ln w 0A I --I > Q v Z m M r-I M N r-I r-I N M Ln W w w W W W W N N N N N N n n N L0 i-L VI ei �I C a° a 0 LL L }J N N Ln N lP Ln V1 In In to In In In Ln Ln Ln L.l1 L.l1 Ln N N L/1 V1 L!1 LA Ln V1 O Q i••L Q m m m m m m m m m m m m m m m m m m m m m m m m m m m Q0 Z m m m m m m m m m m m m m m m m m m m m m m m m m m m V 10 noonc -r-I J d 00 -tt r-I rn Cl) m -;t w V N 00 rn N M LO r-I M 4+ i•. N N w Ln N rn H M Ln r-I Q m r-I m H Ln r-I m ei M N M N qq M m m L. 0. N C 7 m m . M W r-I H-q 0) W Ln W m w 14-* W vi 00 n O m rn It [i r-1 w m M-* m m N Ln 00 a-i Ln 01 M 00 N N N N Ln 00 -9t LL i-L M - N w • N Ln 41 rn Ln N 0) N rn Ln N 00 M ei N V N N 00 m r-I M UD C Q) 6 N W m W m 00 00 m m 00 •. 10 •• O L. IA • Ln m •. .. .. + m M M M M M M M v v v v v v Ln Ln Ln L c V M W H Ln r-I r-I N RT Ln n 00 r-I r-I r1 ri ei ei t l H H ei ei r-I ei r-I r-I r-I e-1 O O i-L •ri 1 a 00 L. Lo V +J Ln c Ln •• 0J O m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln m Ln 4J 0 L. •,I a s Ln Ln W W N N 00 00 0\ 0) m m H r-I N N M Ln Ln Ln W W N N ei V 7 4J . . . . . . . . . . . . . . . . . . . . . . . . . . . . O1 c O L0 ri ei 1; r4 ti 'i ei ei ei ri r- 1; N N N N N N N N fV N N N N N N N 'O •n •r1 i-+ > W W W 00 00 tb 00 00 00 00 00 W 00 00 00 fb 00 00 00 00 W 00 DO 00 W 00 00 OD c O Ln C LL OL OL 01 T O\ 01 T fT 0� OL OL 01 OL OL 01 01 01 01 01 01 01 01 01 01 OL T 01 01 O L. L0 O r-I •. '. '. '. n.0_m Vu, vvvvvvvvv�taavvvvvvvv'v'v'vvvav'v I ' .-inmdLnmLnwmmmnmHLninmm * H n N M M N m 1� m N Ln LD M M e-1 M M 00 N d m%D M m LD m m LD m m d e4 d d N m M 1� ei w N C0 W d ' 0o d H m w m m e-1 LD m m 0o m m 1� �D Ln LO m N d LD 01 N Ln 1� m d 1� m LD m m 1l 14 d 00 N LD Ln m 1� d d Ln Ln Ln l0 l0 LD n n 00 DD 00 01 01 T m m c-1 N N rl ri ei 'i ei ei ei ei e-1 a -I e-1 e-I t-i e-1 ei t-I N N N N N d LD LD c-1 H Ln Ln d m 0o LD 0o M N d m m m H m LD In N 01 M M e-I m l0 d m M 01 L-1 00 m 01 d N N a-i 01 ' O� tD N m l0 d 01 d tp m m I� LD a a M d LD m N Ln n tD n 00 00 m m c-1 N m d d Ln LD 1� 00 m m N 00 H n N N N N M M M M M M M m m M m M d d M d M m m d m oo LD ei Ln ci d d m w m Ln Ln In m n m oo m l!1 Ln to m ao (V ao Lo d In rn rn m " w X m LD LD N N H, Ln Ln r4 d e 4 00 M 01 Ln m "; 1z Ln 00 d i-L M M W M m N d n H m LD N m 00 00 m H d Ln 01 M • LO m d oo m n c-I Ln m ON fn oo fn N N 1� Moo Q7 m LO � d Ln Ln Ln LD w n n oo oo m 01 m m H H N N m Ln Ln N H r-I r-I r-I e-1 r-I e-1 r-I e-1 rl TA H N N N N N N N N N LA -H 4) C' NI L m r L. O Ln m 1n Ln N I� M m m 00 m Ln N In In d I I� m %D 4-+ Ln m M LD Ln N 01 e-I 00 00 d LO Ln N I� e-1 M d r-I Ln Ln . . . . . . . . . . . . . . . . . . . . L 01 LD m to m oo d rn t0 m 1� tD Ln to LO I� m d m m t0 Ol 1, 01 m m r-I r-I N N m Ln LD N 00 0) m N rn LD 1� fn collrn1* t ddd dddddLnLnLnLnLnLn Ln Ln c 0 0 O_ Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln Ln . m m m m m m m m m m m m m m m m m m m m m m m CD CD m m m m m m m m m m m m m m m m m M M H Ln N LD M m H N M M M 00 m Ln H oo d M LD M N d N 0o m Ln m LD Ln W M H d M m W d H m 00 . . . . . . . . . . . . . . . . . . . . . N Co LO d Ln m m 1; 1; Co 01 n 1; fn Yn 0o Ln d 10 N r 1 n m m m CC m N m w ID LD CC m m m m m d d 1� n %D CC m N M LD CC m N n m m N 14 Ln 0) d 01 d M 00 Ln Ln LD LD LD LO LD n n n oo CC o0 01 0) 01 m m e I N m r-I r-I e 4 H r-I r-I H H e-1 ei H r-I H r-I r-I H N N N N N m m m m Ln m Ln m Ln Ln m m m Ln m Ln m Ln 000 W m m m m ri ei N N m d d Ln Ln w LD N n 00 m m N N N M M M M Pn m m M m M r' M Yn M M m Pn d 00 DO 00 W 00 DO W DD W 00 00 W DO W W 00 00 00 W 00 QO 01 01 01 OL 01 01 O\ 01 O� O� 01 01 01 O1 01 01 01 Q> 01 01 T v v v v v v v v v v v v v v v v v v v v v a Pond Report Hydraflow Hydrographs Extension for AutoCADV Civil 3D@ 2016 by Autodesk, Inc. v11 Saturday, 06 / 17 / 2017 Pond No. 1 - Pond 1 Pond Data Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 4982.00 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cult) 0.00 4982.00 13,207 0 0 0.50 4982.50 14,574 6,945 6,945 1.00 4983.00 16,204 7,694 14,640 1.50 4983.50 18,731 8,734 23,373 2.00 4984.00 20,874 9,901 33,275 Culvert / Orifice Structures ' [A] [B] Rise (in) = 4.00 0.00 Span (in) = 4.00 0.00 No. Barrels = 1 0 Invert El. (it) = 4981.35 0.00 Length (ft) = 0,00 0,00 Slope (%) = 0.00 0.00 N-Value = .013 .013 Orifice Coeff. = 0.60 0.60 Multistage = n/a No Weir Structures [C] [PrfRsr] [A] [B] [C] [D] 0.00 0.00 Crest Len (ft) = 5.00 0.00 0.00 0.00 0.00 0.00 Crest El. (ft) = 4983.00 0.00 0.00 0.00 0 0 WeirCoeff. = 3.13 3.33 3.33 3.33 0.00 0.00 Weir Type = Broad - - -- 0.00 0.00 Multi -Stage = No No No No 0.00 n/a .013 n/a 0.60 0.60 Exfil.(in/hr) = 0.000 (by Wet area) No No TW Elev. (ft) = 0.00 Note: Culvert/Odfice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for onfice conditions (ic) and submergence (a). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft curt ft cis cis cfs cfs cfs cfs cis cfs cfs cfs cis 0.00 0 4982.00 0.29 is - - - 0.00 - - - - - 0.290 0.50 6,945 4982.50 0.41 is - - - 0.00 - - - - - 0.414 1.00 14,640 4983.00 0.51 is - - - 0.00 - - - - - 0.508 1.50 23,373 4983.50 0.59 is - - - 5.53 - - - - - 6.121 2.00 33,275 4984.00 0.66 is - - - 15.65 - - - - - 16.31 r Hydrograph Report rHydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. 00.5 Wednesday, 05 / 10 / 2017 Hyd. No. 1 Basins 1,01 and 03 Hydrograph type = Rational Peak discharge = 18.90 cfs Storm frequency = 100 yrs Time to peak = 8 min Time interval = 1 min Hyd. volume = 12,109 cuft Drainage area = 3.280 ac Runoff coeff. = 0.59 Intensity = 9.765 in/hr Tc by User = 8.00 min OF Curve = LEG.IDF Asc/Rec limb fact = 1/1.67 tr r 1 rBasins 1,01 and 03 Q (cfs) Hyd. No. 1 -- 100 Year 21.00 18.00 r 15.00 12.00 r 9.00 r 6.00 i ' 3.00 0.00 0 2 4 6 8 10 12 ' Hyd No. 1 14 16 18 20 Q (cfs) 21.00 18.00 15.00 12.00 9.00 6.00 9911I01 1 0.00 22 Time (min) I Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 31)® 2016 by Autodesk, Inc. v11 Saturday, 06 / 17 12017 Hyd. No. 2 Pond 1 Routing Hydrograph type = Reservoir Peak discharge = 0.471 cfs Storm frequency = 100 yrs Time to peak = 0.35 hrs Time interval = 1 min Hyd. volume = 52,992 cuft hyd. No. = 1 - Basins 1,01 and 03 Max. Elevation = 4982.79 ft IInflow Reservoir name = Pond 1 Max. Storage = 11,417 cuft Storage Indication method used. Pond 1 Routing Q (cfs) Hyd. No. 2 — 100 Year 21.00 ' 18.00 ' 15.00 12.00 9.00 6.00 3.00 0.00 L i I I 0 5 10 15 20 25 30 35 40 ' Hyd No. 2 Hyd No. 1 EEEEEFIi Total storage used = 11,417 cuft 45 Q (cfs) 21.00 18.00 15.00 12.00 Me] 3.00 —L 0.00 50 Time (hrs) II I I I I I I I r PMJear: [EC. 1707.00 Aare: 02/72111 .SCeb: NA M gy I Weirs of Trapezoidal Section Figure 5.9 represents a weir of trapezoidal section with both upstream and downstream faces inclined. Experiments on this type of weir were made by Bazin and the U.S. Deep Waterways Board. Bazin's experiments were all on weirs 80 cm high, the breadth of crest 4.B varying from 20 to 40 cm. Experiments on two weirs of this type, each 1.5 m high, were performed by the U.S. Deep Waterways Board. Coefficients covering the range of Bazin's experiments are given in Table 5.7. Table 5.8 gives coefficients resulting from the experiments the U.S. Deep Waterways Board. For weirs of trapezoidal cross section with sloping upstream face and vertical downstream face (Fig. 5.10) there are five series of experiments by the U.S. Deep Waterways Board. All the models for these experiments were approximately 1.5 m high, and the breadth of crest AB was either 10 or 20 cm. The length of all weirs was 2 m. Table 5.9 gives coefficients derived from these experiments. Tsble 3 9 • Vatu Cm the Formula°Q XIR34for Weiis of TzapezoldW C4osi,Se6tron withnBoth FiLces.�Tnchned. Thin -table ind,antu that raloa-d C mexeane:elishti➢ fa- r.:Eeride aboml':5[t• !;Beaa"oleo Tab1e�S10. � -� .Table b10 •' Values of C;in•the-Fo;mu_la Q &1144. for*ein of Trapentiidal Cross. Section with Both Faces:Inellneil 81ope o0up• etieau f 3fdce'I' 916peot dowo- atrmm flea" :Width of areal in � feet r CHead w [eel, H: , � 0.2IOb.3l0 4�0 SIO.BIO TIO BIO::eh 041 Rll:b 1'taa ltol O88 PTO 1Lffi�Y BB301 E:133 Yi8 st $uaSYa BeV.ffi i.eoa' aeoi" Bss 2rns_9e 2.70 ffi2azs.6sa.ulazraazaasasBla'a>.. 2:7B2 801a BlE 0I a 14 3.21 3 2f S 37IJ 45 i<w a l�to2 a to r 4to I' B es�` OB8 271�2.7iR 813883 .00I3 �308312317 211 YeiE 38 1 toS to btol O88 1 21 ariS8012887a ' 2 7111 7f�Y 882'93�802a 80'8 80ia & 08 2.882l93 J-12317a fte �328 r J�YZ 1 1'to2 4to 31i t32� 7B8 WY.ffi 2.ffi5854 2012 %S01 J.10 1 �toS 1Bb L32 .IR 78280� ffi88688 90Yai 88 '08 a.toI i5Sto 1,007 .82Y S48oil' 8133203 253353383 i3 818'81 I Loll LS to087 27312�882 C1E@a'i31:1�3 YOa 983 53 J:88 1'to�8 Ito 1.087 8S02 fi2R 752 isals 87408804E 7-Iso o4s.ie 3:27a M3i83S8 s?si .--:VertSad !Y to3 o m a:sb ael2, a seia �a?6�2O6ID i etrwml I ofWCrot: I 'Hoed ,n [eel -H y � ILBI! I II t�O face wieet 8�2 0.12b IJ 0�3 5I£ OIi blb OIS�B; So B o ig '2to1 2toi1'; I OB7 ab7�3383563:S1E88lsSol ssamasu b�to:l: 083 3:583.Sej]:BJIS:+IB J.ia 3.4.t a3.513.b73.38 H LEGACY AUTO FDP WEIR COEFFICIENTS TRAPEZOIDAL SECTION WATER SURFACE REF: HANDBOOK OF HYDRAULICS, BRATER AND KING, 1976 WOHNRADE CIVIL ENGINEERS, /N J37 W. Akrn Stmr Bonug,on, /rinoir, 60710 Pgone: (847)381-17I5, Far: (817).TBl-7746 ShBBi I I I 1 1 0 I Design Procedure Fonn: Extended Detention Basin (EDB) Sheet 1 of 4 Designer: Mary B. Wuhmade, P.E. Company. Wohnnde Civil Engineers, Inc. Date: May 11, 2017 Project: Legacy Auto F nod Development Plan Location: Fort Collins, Colorado i. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, 1. = 43.0 % B) Tributary Area's Imperviousness Ratio (i = I, / 100) 1 = 0.430 —1 C) Contributing Watershed Area Area = 3.280 ac D) For Watersheds Outside of the Denver Region, Depth of Average it, = 0.43 in Runoff Producing Stony. jChaoe One E) Design Concept (Select EURV when also designing for flood control) ' I ®Water Quality rapture Volume (WQCV) OExoess Urban Runalf Volume (EURV) F) Design Volume (WQCV) Based on 40-hour Drain Time VDES..=, OASt —1 ao-ft (Voesm = (1.0' (0.91 ' i'- 1.19 - r - 0.78' i) / 12' AM) G) For Watersheds Outside of the Denver Region, VDEs1cu OTHER=, 0.051 1 Soft Water Quality Capture Volume (WQCV) Design Volume (V..OTHER = 1d6 (VOESIDR/0A3)) H) User Input of Water Quality Capture Volume (WQCV) Design Volume Voesicu uses= Soft (Onty if a different WQCV Design Volume is desired) Choose One 1) Predominant Watershed NRCS Soil Group OA WQCV selected. soil group not required. OB OC/D J) Excess Urban Runoff Volume (EURV) Design Volume For HSG A EURV,=1.68'i"' ___ _ _ __ _ EURV =' ,ao-ft For HSG B. EURVs = 1.36' i''P For HSG C/D: EURVc c = 1.20' I'm 2. Basin Shape: Length to Width Ratio L : W = 2.0 : 1 (A basin length to width ratio of at least 2:1 will improve TSS reduction.) 3. Basin Side Slopes A) Basin Mabmum Side Slopes Z = 4.00 ft /ft (Horizontal distance per unit vertical, 4:1 or flatter preferred) 4. Inlet Ri ra A) Describe means of providing energy dissipation at concentrated inflow locations: 1 UD-BMP_v3.05.tdsm, EDB 5/1112017, 11:33 AM I I 1 I 1 Design Procedure Forrn: Extended Detention Basin (EDB) Sheet 2 of 4 Designer: Mary B. Wohnrade, P.E. Company Wohnrade Gvll Engineers, Inc. Date: May 11, 2017 Project: Legacy Auto Final Development Plan Location: Fort Collins, Colorado 5. Forebay A) Minimum Forebay Volume Vraw = 0.001 —� ac:ft Nrwx = 1% of the WOCV) B) Actual Forebay Volume VF= ao-ft C) Forebay Depth (DF = 12 inch ma)dmum) DF = in D) Forebay Discharge i) Undetained 100-year Peak Discharge O,m = cis it) Forebay Discharge Design Flow OF=, - —� ds (aF = 0.02 • Q,m) E) Forebay Discharge Design OBerm h WPipe (flow too small for bew/ pipe) OniWall �te hRestt1od OWaB with VNalch Weir F) Discharge Pipe Size (minimum 8-inches) Calculated DF = 1 in G) Rectangular Notch Width Caiwtated Ws= - -! in 6. Tdclde Channel Goose One Ocancrete A) Type of Trickle Channel Osoft Bottom F) Slope of Tricide Channel S = 0.0044 ft / ft 7. Micropocit and Outlet Structure A) Depth of Micvopool (2.5-feet minimum) ON, = 2.5 ft B) Surface Area of Micr0000l 110 ft minimum) A. ` 10 sq ft C) Outlet Type Goose One ®0d6ce Plate 001her (De cube): D) Smallest Dimension of Orifice Opening Based on Hydrograph Routing (Use UD-Detention) D„m.= 0.44 inches E) Total Outlet Area Aa = 0.45 square inches ' UD-BMP_v3.05.)dsm, EDB 5/11/2017, 11:33 AM I i 1 1 1 1 1 r � I 1 1 1 1 1, 1 Design Procedure Forrn: Extended Detention Basin (EDB) Sheet 3 of 4 Designer. Mary B. Wohnmde, P.E. Company: Wohnnde Civil Engineers, Inc. Date: May 11, 2017 protect: Legary Argo Final Development Plan Location: Fort Collins, Colomdo 8. Initial Surcharge Volume A) Depth of Inital Surcharge Volume Do = 4 in (Minimum recommended depth is 4 inches) B) Minimum Initial Surcharge Volume Vas ='7 cu it (Minimum volume of 0.3% of the'dv'QCV) C) Initial Surcharge Provided Above Micropool V.= cu ft 9. Trash Rack A) Water Quality Screen Open Area: A, = A„' 38.5'(eQ0°aa) A, = 17 square inches 8) Type of Screen (If specifying an alternative to the materials recommended 5.5. PHI wean i im 60% open area i in the USDCM, indicate "other" and enter the ratio of the total open are to the total screen are for the material specified.) Other (YIN): ^ N C) Ratio of Total Open Area to Total Area (only for type'Other') User Ratio = D) Total Water Quality Screen Area (based on screen type) Ae,,= 28`-- I sq. in. E) Depth of Design Volume (EURV or WQCV) H= 0.65 feet (Based on design concept chosen under 1 E) F) Height of Water Quay Screen (Hra) HTa= 35.8 inches G) Width of Water Quality Screen Opening (W,r..e) w ,,.o = 12.0 —� inches (Minimum of 12 inches is recommended) 1 UD-BMP_v3.05.Idsm, EDB 5/1112017, 11:33 AM Design Procedure Form: Extended Detention Basin (EDB) Sheet 4 of 4 Designer: Mary B. Wohnrade, P.E. company: Wohnrade CW11 Engineers, Inc. Date: May 11, 2017 Project: Legacy Auto Final Development Plan Location: Fort Collins, Colorado 10. Overnm Embankment A) Describe embankment pmlecfim for 100-year and greater overtopping: B) Slope of Overflow Embankment (Horizontal distance per unit vertical, 4:1 or flatter preferred) Riprap protection wil be pmvided at the detention pond emergency overflow weir. 4H:IV 11. Vegetation Choose One OImgz ®Nat Irrigated 12. Access A) Describe Sediment Removal Procedures Notes: L I t ' UD-BMP_v3.05.1dsm, EDB 5/1112017, 11:33 AM m i � e � m ♦ A ♦ Z ♦ CJ i� \ D Z \\ \ fl!o aq �P 6 � I J V \l NORTH COLLEGE AVENUE t,9 I 9l / l I 1984 \ I _-- ___.Ex6pw BU/LO/ 407 a 1 I I \ 1.60 ml I - 1.5 I i _ I � i y 190f 1k� I '�6Zt I to I Iry M I 1.91 I I �I I I � % 1 v I � 1 1 al I $ I II1 I 1 ' I I i\ I \ I\ \ I \ I 1 I \' I 1 f I I I ' I e 8 '80% I a rn I b° m -'k33) � ce Ifto \ \ SR E195 MG r.... r _ rzw wttLrox Cr r r. r.r�.r.... u.......ra ... i.....uu..9v u... v.............. v..0 IN 90' LEaEh®. 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EXSTMV S4A#Wr S LM'E EXISnN WXIER URF Ex$pN Us EWE M EXISnR O✓ERNEXU mwR EWE .� asnWC UNOfRU w PoMER 1,mr I'•r IXSnw fMIXRCROIMO G%E N N AL9 EON XNTER ✓kL OEOI0 s TREF F,—ST— EvsrNc S10M1 YWFR Ery51WL STORM SEKR Wn IMCI F, �a M smite p Sro SI SEWER OR XLK r R 5E0 S10RM SEWER MTH MECf SMD - EWSVN UwmR zD RR CO ro 6vR PRO/Ecl/w NUU, ----..._ vslE USN NENRY M Bl5/N ?AEN7p UwN 50 Am A R XORES MSY RO/NT 40 9 M 120 Feet R n I City of Fort Collins, Colorodo UTILITY PLAN APPROVAL /e9�.xu CXECNED B(: Y'Gry x wv.�. t Wy A� ENEMM ar' M,EQ,aa D,: . r P1EC1{ED W a\EQx W, �uM�rv....mi L uj ''R•m�„ � orv+�` R SAaef 2 ---------------------------- ------------------ NORTH COLLECE AVENUE — wz• y..w ___ \ rtp �I99I" AY'vNr s[Orc I990 •• •n �^ _ _ sip 19&1 Ift.. 0.64X I9e7L� -1.02X 1` C 'I • a E sw 5zr.ur.r < ■ ew sm .r ■ q Exn'Pmn / xrpewr - �6 g b Dd ExrsPw WAa vote \ \ \ /� / \ Nk n` `� Me> _ g ■ Oa exKnvc sewEx u.N/.arE \ \ \ L h a vaoPasEa euaaNc .aoo/rmN a :I Est 1645 N. 6YIGE AVENUE Y--_ w111_ Pa Exrsnxc smxN /uwraE F. 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I Q AWw /N aC°es \ ♦\ � so'.wrueu �AreurrrR zoNc�/ t �T/ 9� / / 2$f � �.��El /P/AM1WSEO UEIENMV A D , El B nyF_ya9' 40 0 10 /10 F f a tfIj 333 MMM Mar r30325 Iw ' y.,•,erm, L , � a \� rrrrprrrrrrrrrrrrrrrrrrrrrrr. a - -... ..rrr...rrr...r...rri..rr.. u..rr..ruuuo. uruoouuu..-.