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Drainage Reports - 10/22/2017
t,cwof I. L. Collins ed Plans wrol By Date 0 J, = �� FINAL DRAINAGE REPORT Harmony Commons Second Filing Lot 2 Prepared for: Brinkman Development 3528_ Precision Drive, Suite 100 Fort Collins, CO 80528 (970)667-0954 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A Windsor, Colorado 80550 (970)674-3300 July 28, 2017 Job Number 1254-045-01 INTERWEST C O N 5 U L T I N G G R O U P ' July 28, 2017 Mr. Wes Lamarque City of Fort Collins Stormwater ' 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage Report for Harmony Commons Second Filing — Lot 2 Dear Wes, ' I am pleased to submit for your review and approval, this Final Drainage Report for the Harmony Commons Second Filing — Lot 2 development. The City of Fort Collins review comments dated ' July 14, 2017 have been addressed in this report. I certify that this report for the drainage design was prepared in accordance with the criteria in the City of Fort Collins Storm Drainage Manual. I appreciate your time and consideration in reviewing this submittal. Please call if you have any ' . questions. ' Sincerely, Reviewed By: ' Erika Schneider, P.E. Michael Oberlander, P.E., LEED AP Colorado Professional Colorado Professional Engineer No. 41777 Engineer No. 3421 ' 1218 WEST ASH, SUITE C WINDSOR, COLORADO 80550 rE1. 970.674.3300 • rill. 970.674.3303 TABLE OF CONTENTS TABLE OF CONTENTS ................................................... ... ' 1. GENERAL LOCATION AND DESCRIPTION................................................................ 1 1.1 Location................................................................:..........................................................1 ' 1.2 Description of Property................................................................................................. 1 1.3 Floodplain Submittal Requirements............................................................................. 1 ' 2. DRAINAGE BASINS AND SUB-BASINS.......................................................................... 2 2.1 Major Basin Description................................................................................................ 2 2.2 Sub -basin Description.................................................................................................... 2 3. DRAINAGE DESIGN CRITERIA...................................................................................... 2 3.1 Regulations......................................................................................................................2 3.2 Directly Connected Impervious Area (DCIA) Discussion .......................................... 2 3.3 Development Criteria Reference and Constraints...................................................... 4 3.4 Hydrological Criteria..................................................................................................... 4 3.5 Hydraulic Criteria.......................................................................................................... 5 3.6 Floodplain Regulations Compliance............................................................................. 5 3.7 Modifications of Criteria............................................................................................... 5 4. DRAINAGE FACILITY DESIGN....................................................................................... 5 ' 4.1 General Concept............................................................................................................. 5 4.2 Specific Details................................................................................................................ 5 ' 5. CONCLUSIONS....................................................................................................................8 5.1 Compliance with Standards.......................................................................................... 8 5.2 Drainage Concept........................................................................................................... 8 6. REFERENCES...................................................................................................................... 9 ' APPENDIX VICINITY MAP AND DRAINAGE PLAN.............................................................................. A HYDROLOGIC COMPUTATIONS..........................................................................................B ' HYDRAULIC COMPUTATIONS..............................................................................................0 WATER QUALITY AND LID INFORMATION.................................................................... D EXCERPTS FROM REFERENCE REPORTS......................................................................... E 1 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location The Harmony Commons Second Filing — Lot 2 is located in the Northwest Quarter of Section 4, Township 6 North, Range 68 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. Please refer to the vicinity map in Appendix A. The project site is located at the southwest corner of E. Harmony Road and Lady Moon Drive. Lot 3 of Harmony Commons bounds the property on the east, E. Harmony Road ' and Outlot A on the north, Harmony Commons Second Filing — Lot 1 on the west and Lot 6 of Harmony Commons on the south. 1.2 Description of Property ' The property consists of about 0.96 acres of land and will consist of a new building, new parking and drive aisles. The site generally slopes in an easterly direction at approximately 0.5% to 1.0%. The land is currently vacant. According to FEMA Panel 08069CO994F there are no mapped FEMA Floodways on this ' property. ' 1.3 Floodplain Submittal Requirements Because the project is not within any FEMA or City of Fort Collins mapped floodway, a Floodplain Submittal is not required and a "City of Fort Collins Floodplain Review Checklist for 100% Submittals" has not been included with this report. ' 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The proposed development lies within the McClellands Basin and McClellands Creek Master Drainage Plan. The overall development has been designed with a master plan by Stantec Consulting, Inc. and titled "Final Drainage and Erosion Control Study Harmony Technology Park Site Master Plan", dated May 19, 2008. The area was also designed with a drainage report by Interwest Consulting Group, Inc. and titled "Final Drainage Report Harmony Commons Subdivision', dated March 11, 2016 and approved by the City on May 16, 2016. 2.2 Sub -basin Description Historically, the site generally drains to the storm system in Lady Moon Drive and Rock Creek Drive and eventually reaches the Fossil Creek Reservoir Inlet Ditch (FCRID). 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual" specifications. Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual" (UDFCD), developed by the Denver Regional Council of Governments, has been used. ' 3.2 Directly Connected Impervious Area (D.CIA) Discussion ' Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process for receiving water protection that focuses on reducing runoff volumes, treating the water quality capture volume (WQCV), stabilizing drainageways and implementing long-term source controls. The Four Step Process applies to the management of smaller, frequently ' occurring events. 2 Step I: Employ Runoff Reduction Practices To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement ' Low Impact Development (LID) strategies, including Minimizing Directly Connected Impervious Areas (MDCIA). ' Runoff from the parking lot and surrounding sidewalks shall drain directly into porous ' pavement systems thereby slowing runoff and also promoting infiltration ' Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow Release Once runoff has been minimized, the remaining runoff shall be treated through the porous ' pavement system. The porous pavement system allows for settlement of sediments. ' Step 3: Stabilize Drainageways Natural Drainageways are subject to bed and bank erosion due to increases in frequency, ' duration, rate and volume of runoff during and following development. Because the site will drain to a master planned regional water quality and detention pond, bank stabilization is unnecessary with this project. Step 4: Implement Site Specific and Other Source Control BMPs ' Proactively controlling pollutants at their source by preventing pollution rather than removing contaminants once they have entered the stormwater system or receiving waters ' is important when protecting storm systems and receiving waters. This can be accomplished through site specific needs such as construction site runoff control, post - construction runoff control and pollution prevention / good housekeeping. It will be the responsibility of the contractor to develop a procedural best management practice for the site. 1 ki 3.3 Development Criteria Reference and Constraints ' The runoff from this site has been routed to conform to the requirements of the City Stormwater Department and the approved Harmony Technology and Harmony Commons ' drainage plans. Because water quality capture volume from this site will be provided for in the downstream regional detention and water quality pond 301, water quality facilities ' are not required for the site. However, City LID requirements are necessary therefore; additional water quality will be accomplished through the use of the porous pavement systems that include 12" of storage in the voids below the pavers. The impervious area ' for the site has also already been accounted for in Pond 301 and was assumed to have a C value of 0.80 and an impervious value of 80%. Please refer to supporting documentation in Appendix E. Runoff reduction practices (LID techniques) are also required. No less than fifty percent of any newly added impervious area must be treated using one or a combination of LID techniques. The project adds 41,768 sf of new impervious area. Using the porous paver LID technique, 30,980 sf of new impervious area (74%) will be treated which exceeds the 50% requirement. No less than twenty five percent of any newly added pavement areas must be treated using a permeable pavement technology. The project adds 27,807 sf of new pavement area. This project will incorporate 9,462 sf of porous pavers which is 34% of the newly added pavement which meets the required 25%. Please refer to Appendix D for LID calculations and information. 3.4 Hydrologic Criteria Runoff computations were prepared for the 10-year minor and 100-year major storm ' frequency utilizing the rational method. All hydrologic calculations associated with the basins are included in Appendix B of this ' report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub - basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub - basins and Design Points associated with this site. 4 Water quality capture volume and detention has been provided for in the downstream regional detention and water quality pond 301. 3.5 Hydraulic Criteria ' All hydraulic calculations are presented in Appendix C of this report and are prepared in accordance with the City of Fort Collins Drainage Criteria. Hydraulic calculations include inlet capacity spreadsheets z and StormCAD calculations. 3.6 Floodplain Regulations Compliance ' The project is not within any FEMA or City of Fort Collins mapped floodway; therefore, Floodplain Regulations Compliance is not required. 3.7 Modifications of Criteria ' There are no Modifications of Criteria for this development. ' 4. DRAINAGE FACILITY DESIGN 4.1 General Concept ' The majority of the proposed development will be collected and conveyed to the ' proposed storm drain system via porous pavement systems before being conveyed under Timberwood Drive to Pond 301. ' 4.2 Specific Details ' A summary of the drainage patterns within each basin is provided in the following paragraphs. Lot 1 of Harmony Commons Second Filing is included in this analysis. This ' area will be developed in the future. Please refer to Appendix A for the drainage plan. 5 PROPOSED DEVELOPMENT (LOT 2) Basins Kl, K2 and K3 are 0.38, 0.41, and 0.40 acres, respectively. They contain the parking lot, drive aisle and building on Lot 2. Basin K1 is calculated to have a 10-year discharge of 1.3 cfs and a 100-year discharge of 3.4 cfs. K1 contains the southern portion of the parking lot and drive aisle. Flows from Basin K1 are captured by a porous paver system with 12" depth where the 100-year flow will be detained and reduced to 0.4 cfs with an orifice plate and some minor parking lot flooding (4.5 inches max). ' Basin K2 is calculated to have a 10-year discharge of 1.5 cfs and a 100-year discharge of 4.0 cfs. Flows from Basin K2 are captured by a porous paver system with 12" depth ' where the 100-year flow will be detained and reduced to 0.9 cfs with an orifice plate and some minor parking lot flooding (3 inches max). An underdrain system will release this flow into the proposed storm system. This system ' releases into the existing double 5'x2' box culvert under Timberwood Drive. This culvert directs flow south to Pond 301. ' Basin K3 is calculated to have a 10-year discharge of 1.0 cfs and a 100-year discharge of 2.7 cfs. This basin contains the building of Lott. Flows from the building roof will be ' collected in 15 inch roof drains that will drain to the same proposed storm system that releases into the existing double 5'x2' box culvert under Timberwood Drive. The weighted average C value of the site is 0.72 which is below the Harmony Tech Park model assumption of 0.80; therefore, detention is not required on -site and is provided for in the regional Pond 301 located south of the site. Please refer to Appendix E for excerpts from the Harmony Tech Park design. 6 FUTURE DEVELOPMENT (LOT 1) ' The final design of the future development will occur when this project submits a PDP/FDP. Basin Jl and J2 are 0.92 and 0.65 acres, respectively and contain Lot 1's parking lot and building. ' Basin J1 is calculated to have a 10-year discharge of 2.6 cfs and a 100-year discharge of 7.1 cfs. Flows from Basin J1 will be captured by the porous paver system where the 100- year flow will be detained and reduced to 1.6 cfs. An underdrain system will release this ' flow into the proposed storm system of Lot 2 that will release into the existing double 5'x2' box culvert under Timberwood Drive. ' Basin J2 is calculated to have a 10-year discharge of 1.7 cfs and a 100-year discharge of ' 4.5 cfs. Flows from the building roof will be collected in 15 inch roof drains that will drain to the same proposed storm system that releases into the existing double 5'x2' box ' culvert under Timberwood Drive. Basin C2 was adjusted from the original area of the Harmony Commons drainage study. ' The area is 0.26 acres and is calculated to have a 10-year discharge of 1.0 cfs and a 100- year discharge of 2.6 cfs. Flow from this basin is captured by the existing 5' Type R ' sump inlet in the drive aisle at design point c2. This inlet directs flow to the existing storm system that releases to the existing double 5'x2' box culvert under Timberwood ' Drive. 7 5. CONCLUSIONS 5.1 Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual. 5.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provides for stormwater quantity and quality treatment of proposed impervious areas. Conveyance elements have been designed to pass required flows and to minimize future maintenance. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit will be required. . 8 6. REFERENCES 1. Interwest Consulting Group, "Final Drainage Report Harmony Commons Subdivision", dated March 11, 2016. 2. City of Fort Collins, "Fort Collins Stormwater Criteria Manual Amendments to the Urban Drainage and Flood Control District Criteria Manual", adopted December 2011. 3. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated November 2010. 4. JR Engineering, "Final Drainage and Erosion Control Report Harmony Technology Park Second Filing", dated June 20, 2001. 5. Stantec Consulting, Inc., "Final Drainage and Erosion Control Study Harmony Technology Park Site Master Plan", dated May 19, 2008. 9 APPENDIX A VICINITY MAP AND DRAINAGE PLAN A ' HARMONY COMMONS, SECOND FILING LOT 2 ' SCALE: 1 "=500' _ _ -__.---_____--_----_---------_--- r- � --+ "----- -------------a Y —.. — e a ---- <— -----ate ' -- _ HARMON'COMMONS — — — - -=-------- ..-----------------�- e _ - --- q91_= J _-- . e ---n.---------- ` -__ , _ (UEIDE&AE) DRAT GE SUMMARY TABLE w•pR iHb4vy wu GII51 GNmI 1[p% m115o) 0110" 4100pe1 SMCO••M ROBBINS Pw. 1.1 I••al ImM 1>.1 111.1 Q Q 025 ow IM 5.3 5o Lo 26 EX 6 TYPE R SUMP INLET Jt A Ew OE 09: 52 50 01 BS FUTURE LID J2 R 065 0.35 075 05 57 1.7 45 FUTURE KI KI Dye o7I 1 00 55 So IJ 04 POROUS PAVERS K0 K2 041 070 109: 51 5D 15 40 POROUS PAVERS q Ki 10.4D D.et O& v.t 55 -1.0 27 ROOF STORM SYSTEM ------------ HARMONY COMMONS I • HARMONY COMMONS G2 SECOND FILING 'I SECOND FILING os+ 0.57 HARMONY I LOT 1 I I LOT 2 �. I COMMONS J2 \ I ♦ t LOT 3 I i o.es o.sfi I 1 'FUTURE BUILDING ' I m \ I o I i r — — I EA &I AE I I FUTUF I I I I I �-EA & AE— ... I I I I Icv I AGGEsz umvr Ann (M'A/NACl EA3EMCN7 Ill II _♦ J — — — — — --- -- - -- PARKING 0.92 0.77 1 DE \ I / �V Ac- U&12 AND ... ORAM'AGF EASEMEI / -� 43 FF=4914.8 n 0.40 0.67 '. n 1 FF=4814.8 �IL----- —�i,; IILI :• ..y I• — . I414 5 � 0.33 0 EI i STORM MAIN K 14.0 \ -- - 13.5 El_ - STORM LAT K2 ./ /' now Sommill all all Was So So love to Samoa o / /x, 0.36 0.71 KI \ Y \ ■ 'I X � � IATKII Y \ E2 Y \/ D.71 \ 140 / � , 1 ■ K is --•� \ - So I IJill, 1 14.5 c2 3.5 / 0.22 0,7J 1l ., 17J all 1111 all Ill „•' � N III � �,r,'%' HARMONY COMMONSLOTS CALL UTILITY NOTIFICATION CENTER OF COLORADO 811 CALL 2-BUSINESS DAYS IN ADVANCE BEFORE YOU DIG. GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGRWND MEMBER UTILITIES. 20 10 0 20 40 SCALE: 111 - 20' NOTES 1. ANY DAMAGED CURB. GUTTER AND SIDEWALK EXISTING PRIOR TO CONSTRUCTION. AS WELL AS STREETS, SIDEWALKS, CURBS AND GUTTERS. DES7ROYED. DAMAGED OR REMOVED DUE TO CONSTRUCTION OF THIS PROJECT, SHALL BE REPLACED OR RESTORED TO CITY OF FORT COLLINS STANDARDS AT THE DEVELOPER'S EXPENSE PRIOR TO THE ACCEPTANCE OF COMPLETED IMPROVEMENTS AND/OR PRIOR TO THE ISSUANCE OF THE FIRST CERTIFICATE OF OCCUPANCY. LEGEND s-:i1lC'� EXISTING MINOR CONTOUR 'X%%X_ EXISTINGMAJORCONTOUR XXX� PROPOSED MINOR CONTOUR ----XXXX' PROPOSED MAJOR CONTOUR PROPOSED DIRECTION OF OVERLAND FLOW EXISTING DRAINAGE BASIN DIVIDE LINE A EXISTING DRAINAGE BASIN ID 0.3%0.63 MINOR STORM RUNOFF COEFFICIENT DRAINAGE BASIN AREA. ACRES PROPOSED DRAINAGE BASIN DIVIDE LINE A PROPOSED DRAINAGE BASIN ID 0.3 0.63 MINOR STORM RUNOFF COEFFICIENT DRAINAGE BASIN AREA, ACRES QDESIGN POINT O oED iul �oU) IL 50 4 O 0 1` J O 0 to w6' ZZO y 0 J 0)Z U1 J IL a WODZ Z a he a �a I a)O m N U En v Z J IL 0 Z O W i N N ' Z ww08 a I J It O U cz n ry < w g m CC Z_ m n G G W W < q Y < < W I CITY OF FORT COLLINS, COLORADO O O U UTILITY PLAN APPROVAL pF00 REG,SA APPROVED: 0 .�µll f,A CITY ENGINEER DATE Cp y Y 0 CHECKED BY: J�T 342M WATER & WASTEWATER UTIUTY DATE ..� ` CHECKED BY: STORMWATER UTILITY DATE �rONAL F' CHECKED BY: PARKS & RECREATION DATE PROD. NO. 1213404501 CHECKED BY: TRAFFIC ENGINEER DATE C CHECKED BY: V ENNRONMENTAL PLANNER ppTE APPENDIX B HYDROLOGIC COMPUTATIONS ' W J ¢ m Q ' � Q ' W Q Z ' G F- LU J 2 Z W N a � cc cc � } Y cc cc 2 > > 2 2 Q 0 Q Q cc L U J LL a 0 W W En�jj000- NF ¢o[0 x»000 wLLLLaacc 0 o m ro w u� v o n O V N Op O t7 O (V Q C N O N n th N O V M o c o o n o o m E ui ui vi ui vi ad u o rn n ao w m m n N n n D U o 0 0 0 0 0 ¢ 10 0 0 0 0 0 0 N A a a F N c w c w a 0 am m a Interwest Consulting Group RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Lot 2 - Harmony Commons Subdivision PROJECT NO: 1254-045-01 COMPUTATIONS BY: es DATE: 711012017 Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume I Recommended % Impervious from Table RC-3 Urban Storm Drainage Criteria Manual, Volume I Type B Soils ) Runoff ( % coefficient Impervious C 0.95 100 0.95 96 0.95 90 0.50 40 0.20 0 0.35 0 Streets, parking lots (asphalt): Sidewalks (concrete): Roofs: Gravel or Pavers: Landscape Areas (Flat, heavy) Landscape Areas (Steep, heavy): SUBBASIN DESIGNATION TOTAL AREA (W) TOTAL AREA (Sq.h) ROOF AREA (w.ft) PAVED AREA (sgat) PAVERS AREA (w.h) SIDEWALK AREA (W f1) LANDSCAPE AREA (Wit) RUNOFF COEFF. (C) % Impervious REMARKS C2 0.26 11,301 0 6,991 0 2.016 2,294 0.80 79 1 1.47 64,152 15.656 17,407 10,162 7,427 13,460 0.72 67 J1 0.92 40,086 0 23.578 8,952 3,427 4,129 0.77 76 J2 0.65 28,464 12,871 0 0 1,674 MR20 0.58 46 K1 Ln 16,629 0 9,478 4,813 0 2,338 0.71 69 K2 0.41 17.974 0 8.%7 4,649 3,173 f,285 0.7e 77 K3 0.40 17,336 8,956 0 0 I'mi, 6,I98 0.67 57 TOTALK 1.19 51,9391 8,9561 18,3451 9.4621 5,0541 10,1221 0.72 67 Equations - Calculated C coefficients & % Impervious are area weighted C=£(CI Ai) IAt Ci = ruroff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci IT = number of different surfaces to consider At - total area over which C is applicable; the sum of all Ai's 7-2 17 FC FLOW PDP.aIs d 0 O 0 0) C .j N C O U 2N C N C } O T 'O C l6 N J. z - O m H a N LL z W WIx L o V m Z 3 O E O U. O N y C N CWC L v F 0 IL CO O > U � o N c U Q CC 0 H r O O T C 0 E o N d � N Y W S NN�-N N N N u a z r E ICTIN IL �• N Cl N O O N N O N N = N C N v E m U O O N W N m U z W J W N+! O N N N x a N N m U 7 U � mri eviMve O co J E LL J n N N ND N ND N z > a x C L O O O O O O O C G O 0 O 0 0 0 0 0 0 2 C 0 m o n o O IJ a-.-, o000000 0 a a U' o2°N N v w N 0 0 0 0 0 0 W mi n Q J v f N O N V NO N N N m N NJ N O O o o 0 0 0 O o N N O O O O O O J W 0 JvULU iy O NnnNnnnm N n N N n a 0 0 0 0 0 o 0 z_ F NO n N N N O N c m N Cl? o 0 N � N z m m m U) H ZIM N. T-a A m F f/J O ycoa C l9 C .N N N C_ O U 0 LL O 0 @7 r; N rn I 0 N '0 O D. N N U O ¢ � Z L 7 3 LL Y C U u �p 0 V O Q C N W m E N D m a o c N N C C t0 C N � � � c m E �E Com o c )n \ T n U N U + J O C > o E U E U Z C p E + � m Y i W R u v = E N m N o o N m O N N Z m m E `. ELU u O Y N o N oN N m U 7 N O 4! n tG cq W U � n � n o N N O N O co dmoidd E LL W N �o Z m G G O G G O I > Z U a m m m m m m m R C L o 0 0 C Ea O O O O 000 W m o ` n N wm is(om O: 0 _ N .. S W n voio�won W K n L F N m A N d O Op C� O N .E m MCI 0 0 0 0 0 0 0 O o N 0 0 0 0 0 0 L � tD N N N N IG �r ... v J 0 o o n m rn m n m m n d m m U O J S Q O N n N N n c o 0 0 0 6 0 6 0 E Z_ F CD N n N Q 0? N IQ N 0 d d Z Y Y m U— Y N Z ~ yZ Q m F LD N O U •- ^ N Y Y Y a N C o N 2 0 U Y LL d U O C m E .0— N O N N C N .0 C E C U) N II r .U. .O E E 7 E E U co w l N X a 0 IL O LL LL co N f` LL Z E R M Y Y Q W N IL y G C OB = O F U W O c J IL o Z O '> O a a ci O E E U T O _ r �4 0 N 11 U E O m N H Z N O O Z Z O F D V O i g a 0 a N Y Q w W 6 _O f Q 0 F N C E wE R O p U N O N T O I� 0 0 _ O O N.. 0 0 0 m�nn Nm y e [V lV [V N [V lV N t7 N 0 0 E N N 0 0 N 0 V � n n vmi n n n U c o c a c o c V Q O 0 N N d 0 N 0 0 N O d d LL 0 Z C � N U C 0 c O 0 LL z E O rn ¢ i Q w a G rn O F o U LU i V c C QLL Z O O a Q V N O E E U T O _ r o O CR O O N � II U E } (L O N rn z o° � o zza N Y Q g w 0 H Q O H o_ - U ¢ O O . E c ¢ = o a V o - _ F .59. m d N N N b - a ri a d a e vi C N N N W E N N 6 tD N t0 U mn n�inn� U o 0 o c c c c V O N N 0 O a m N d G) N t7 e d LL ¢ P n U � N s C 0 0 E O Z 0 :) y Y > Q O W O a, O c O_ U C G Q LL v i p s F � u C1 ii c E U C r n 4 0 o 0 N N � e U E Q N Z p � o Z Z Q � U F W � o0oa N Y Q f W Q � Q F O w Q rt E a`c you a U — of _ do<ri<N o E vio vi vi vi vim U g m a n m m U J 0 0 0 0 0 0 LL 0 2 m U N Y Y Y F < O 0 N Y ry Y Y oN a° 0 of exceedance every year). In some instances the 100-year storm routing of runoff will not be the same as that for the 2-year storm. (3) A new Section 1.2 is added, to read as follows: 1.2 Minor (2-Year) Storm Provisions The objectives of such drainage system planning are to minimize inconvenience, to protect against recurring minor damage and to reduce maintenance costs in order to create an orderly drainage system at a reasonable cost. The 2- year storm drainage system may include such facilities as curb and gutter, storm sewer, open channels, drainageways, ponds, rivers, streams, and detention facilities. (4) A new Section 1.3 is added, to read as follows: 1.3 Manor (100-Year) Storm Provisions The objectives of the 100-year storm drainage system planning are to eliminate substantial loss of life or property damage. Major drainage systems may include storm sewers, open channels, drainageways, ponds, rivers, streams, and detention facilities. The correlation between the minor and major storm system must be analyzed to ensure that a well coordinated drainage system is designed and constructed. (5) Section 2.0 is deleted in its entirety. (6) Section 2.1 is deleted in its entirety. (7) Section 2.2 is deleted in its entirety. (8) Section 3.0 is deleted in its entirety. (9) Section 3.1 is deleted in its entirety. (10) Section 3.2 is deleted in its entirety. (11) Section 4.0 is amended to read as follows: 4.0 Intensity -Duration -Frequency Curves for Rational Method The one -hour rainfall Intensity -Duration -Frequency tables for use with the Rational Method of runoff analysis are provided in Table RA-7 and in Table RA-8. Table RA-7 City of Fort Collins Rainfall Intensity -Duration -Frequency Table for Use With the Rational Method (5 minutes to 30 minutes) Duration (min) 2-Year Intensity rnlhr) 10-Year Intensity (1n/hr) 100-Year Intensity (1n1hr) 5 2.85 4.87 9.95 6 2.67 4.56 9.31 7 2.52 4.31 8.8 8 2.4 4.1 8.38 9 2.3 3.93 8.03 10 2.21 3.78 7.72 11 2.13 3.63 7.42 12 2.05 3.5 7.16 .13 1.98 3.39 6.92 14 1.92 3.29 6.71 15 1.87 3.19 6.52 16 1.81 3.08 6.3 17 1.75 2.99 6.1 18 1.7 2.9 5.92 19 1.65 2.82 5.75 20 1.61 2.74 5.6 21 1.56 2.67 5.46 22 1.53 2.61 5.32 23 23 1.49 2.55 5.2 24 1.46 2A9 5.09 25 I A3 2.44 4.98 26 1.4 2.39 4.87 27 1.37 2.34 4.78 28 11.34 2.29 1 4.69 29 1.32 2.25 4.6 30 1.3 2.21 4.52 Table RA-8 City of Fort Collins Rainfall Intensity -Duration -Frequency Table for Use with the Rational Method (31 minutes to 60 minutes) Duration (min) 2-Year Intensity (in/hr) 10•Year Intensity (in/hr) 100-Year Intensity thw%r) 31 1.27 2.16 4.42 32 1.24 2.12 4.33 33 1.22 2.08 4.24 34 1.19 2.04 4.16 35 1.17 2.0 4.08 36 1.15 1.96 4.01 37 1.16 1.93 3.93 38 1.11 1.89 3.87 39 1.09 1.86 3.8 40 1.07 1.83 3.74 41 1.05 1.8 3.68 42 1.04 1.77 3.62 43 1.02 1.74 3.56 44 1.01 1.72 3.51 45 .099 1.69 3.46 46 0.98 1.67 3.41 47 0.96 1.64 3.36 48 0.95 1.62 3.31 49 0.94 1.6 3.27 50 0.92 1.58 3.23 51 0.91 1.56 3.18 52 0.9 1.54 3.14 53 0.89 1.52 3.1 54 0.88 1.5 3.07 55 0.87 I A8 3.03 56 0.86 IA7 2.99 57 0.85 1.45 2.96 58 0.84 1.43 2.96 59 0.83 I A2 2.89 60 0.82 1.4 2.86 (12) A new Section 4.1 is added, to read as follows: 4.1 lntensity-Duration-Frequency Curves for SWMM: The hyetograph input option must be selected when creating SWMM input files. Hyetographs for the 2-, 5-, 10-, 25-, 50- and 100-year City of Fort Collins rainfall events are provided in Table RA-9. 0 24 APPENDIX C HYDRAULIC CALCULATIONS C Interwest Consulting Group 1218 W. Ash, Suite C Windsor, CO 80550 Inlet Flow Calculation for Area Inlet (24" Drop ADS Inlet) Project: Harmony Commons Second Filing Lot 2 Job Number : 1254-045-01 ' Calculations by: es Date : 1/25/2017 ' Objective: to find the number of grates required for area inlets in grassy areas WSEL ' Geometry at inlet ' Grate Open Area and information: Square Feet Open (A): 1.145 sf Reduction Factor (F): 50% Grate Flow: Use the orifice equation Oi = C*A*SQRT(2*g*H) to find the ideal inlet capacity.* 'See Hydraulic Design Handbook by McGraw-Hill for verificaiton of equation use and C value C = Orifice discharge coefficient= 0.67 A = Orifice area (ftz) - open area of grate ' g = gravitational constant = 32.2 fUsz H = head on grate centroid, ponding depth (feet) Then multiply by the reduction factor for the allowable capacity. ' Qc = Oi * (1-F) DP k3 Q = 2.7 cfs Q100 H= 1 ft A= 1.15 fiz ' Q; = C*A*SQRT(2*g*H) 6.16 cfs QG= Q;*F = 3.08 cfs OK Pagel No Text 0 s e S M-Q- N O COS F M m Uoa w ... 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VINA EAi MCNT 10+00 STORM K STA 10+00.0 CX IF SWH ' O N 107361.51 ' E 212576.02 O (D z� I I � I ' 1 t K STA 10+28.1 W SIMH STORM K STA 10+71E� STORM KI STA 10+00.0 STORM I LOT 6 STORM MAIN K STORM LAT K1 STORM K STA STORM K2 STA 24" RCP STORM LAT K1 I II r 6' ED YPOROUS 11 II II STORM LAT K2 LOWER 6" WATER BELOW 24' PCP � T1+60 STORM LAT K2I t 1 1� 6' UD 'I II I i I m I 1 -r' -- -in. - -_ _N'-I - - I STORM K STA 12+23.6 STORM K STA�12+95.9 m I ' / Swill 1 51MH 4w BEEHIVE GRATE CROSSING - - 6, SAN [ i�254B.Ot - _ _ N 10768074 E 212545J] I 12+00 12+40 12+aO I nl I I o 4' RCP 2/' RCP I _ 1 I IN 10 9.62 ' • • Q 1 ^E 21��]S.J9 0 url• f- M' 15' ROOF DRAIN I 1 I R •�.. I,.. I I m I I f- I �I ff I ' HARMONY COMMONS STORM K STA 13+)1.B • $ 24' ADS INLET 07 SECOND FILING 'X N 21" 1..99 I" EI 2128ggg0. 9 6 LOT 2 y o 1 BUILDING ROOF DRAWS f Z I TO BE HARD PIPEO TO I OC _ STORM UNE I I`' I iaa :. O di O W m D " FF=4914.8 e g �' Z? D D a w M `I IS' ROOF DRAW I V o P O I I I •I �i4 = L% cZ 24' ADS INLET14+4 .) C • • s N 107661.24 Q y ° E 21289).61 0 a. R . 0 NOTE: ALL STORM SEWERS ARE PRIVATELY OWNED AND MAINTAINED O 8 YO O AO m m n n 4920 Y YY�� YY�.y. ♦4 p Aq A Y�+N Ns�R Y{^� `;, y�]lL9 P^ �Re����wA�rX.� F w yY<Ip lJ wTv>W \2b OWSWfJ L}u �;� ul lki vG{O02G N inEiainn1KE NnF' VIry i 91e `CXiSANG 1 CkAOE _ ------------7 - INISHED GRADE `tOp- D12 - N0. _ 75.9 LF 15' ROOF OR AI O S-O.BT; 1B LF aB.B LF 24" RCP Y O.x6R 61.6 24' RCP OU $4.0 LF 24" O S-0.23 2.3 LF 24' RCP O S.D.25P 75.9 lF 15' ROOF DRAIN Y Sn0.87% EX TP rCP MIN. is" �- LOWER 6" WATER BELOW 24" STORM TOP-4907.41 (SEE OETAIL) 6, SAW OD 1 20 10TQ 1 60 loFaw 114M 11+20 11+40 11+80 11+Bo 12 OD. 12 20 12443 12 60 12+10 13400 13+20 13+40 1 60 13. BD 1 oo 14420 144AD 1 p2 D n _ Qx Q EBMI 2 O u � 20 10 0 20 40 H s HORIZONTAL SCALE: 1"- 20' W w VERTICAL H SCALE: 1" AA 4' CALL UTILITY NOTIFICATION CENTER OF COLORADO Z - m O 811 a m N 0) 2-BUSINESS SGRACE. O O r BEFORE DIG. 09 EXCAVATE FOR THE 40 O It MMARRING EMBER L�LITIESEPGROUNp N ; w W 2 Z O < G O-Jm a Z a WOUZ Ix 0 Z m0OL (` m 1Nn m NOTES: E ALL STORM SEWER AND WATER CONSTRUCTION. AS WELL AS POWER AND OTHER "DRY' UTILttt INSTALLATIONS. SHALL CONFORM TO THE CITY OF FORT GOWNS 57AND11g05 AND SPECIFICATIONS CURRENT AT THE DATE OF APPROVAL OF THE PLANS BY THE LOCAL ENGINEER. 2. STORM SEWER PIPE SHALL BE RCP OR PVC WITH WATER TIGHT JOINTS AS SPECIFIED ON ,,1 L THEPLAN. ALLSTORM LL SEWER SHABE 1u TRY INSPECTED BY HE COF FORT COLLINSCOLLNS. J LL 3. LENGTH OF PIPE 15 MEASURED FROM CENTER OF STRUCTURE TO CENTER OF STRUCTURE AND LL O INCLUDESTHEFLAREDENDSECTON. Q N i^i 4. NORTHING AND EASNNGS AND ST'ATIONINGS ARE CENTER OF STRUCTURE UNLESS LL OTHERWISE NOTED. O 0 5. SEEARCHITECTURALDRAWINGSFORWALL. LOCATION DETAILS OF GAS U Z METERS. ELECTRIC METERS. ANDWI_EPHONE'TERMINALS. w Mf W ,^ V 6LI . MITSOFSTW REETCLTTSHONARE APPROXIMATE. FINALLIMTFSARETOBE YI DETERMINED IN THE FIELD BY CITY ENGINEER Z N N INSPECTOR. ALL REPAIRS TO BE IN ACCORDANCE WITH CRY STREET REPAIR VJ, STANDARDS. w O O TY 4L T. ANT DAMAGED CURB, GUTTER AND SIDEWALK EXISTING PRIOR TO CONSTRUCTION. AS WELL O IL AS STREETS. SIDEWALKS. CURBS AND GUTTERS. DESTROYED. DAMAGED OR a, It �A G 1, w REMOVED DUE TO CONSTRUCTION OF THIS PROJECT. SHALL BE O REPLACED OR RESTORED TO CRY OF FORT COLONS STANDARDS AT THE DEVELOPER'S EXPENSE PRIOR TO THE ACCEPTANCE OF COMPLETED IMPROVEMENTS AND/OR PRIOR TO r N THE ISSUANCE OF THE FIRST CERTIFICATE OF OCCUPANCY. B. SEE UTILRY PLAN FOR OLTFER BOUNDARY O COORDINATES. IC O QA 4 U) o I- 0 'a w 0 n m �py n £ CC G O < < = D q Y U W CITY OF FORT COLLINS, COLORADO o U UTILITY PLAN APPROVAL RECGS APPROVED: CITY ENGINEER UATT HOD OR' L X�• CHECKED BY: 342e WATER R WASTEWATER UTILITY __DATE �� k CHECKED BY: �1DNAL $TORYWAIER UTILITY DATE E' CHECKED BY: PR03 NO. 1254045G1 PARKS & RECREATION DATE CHECKED BY: TRAFFIC ENGINEER DATE p V CHECKED BY: ENVIRONMENTAL PLANNER DATE I STORWI MAIN K Y tl —i STORM K1 STA 9+T9.3 IB' RCP STUB AND PLUG STORM K STA 10+78.0- STORM K1 STA 10+00.0 5' r SiMH N I07443 06 E 212553.29 STORM MAIN K ACCESS VWrr ANO ONAW/AZI EASEMENT jN 107446.27 _ E 212580.49 _ — — - Uo- PROPERTY LINE (Tm> N 107361.51 ---- — -.- — — — _ — _ — _ E 212576.02 — _ — — — _ — — HARMONY COMMONS LOT 6 HARMONY COMMONS FF=4914.8 SECOND FILING LOT 2 III •� L! '.11 , e •y '.� e �N STORM MNN K 212549.fi1 E 2I25T5.39 _ — — — — — — 6 CX B' SAN 5 1 8' WATER STORM K2 STA 10+ .1 AREA INLE N '07508.44 — — — — — — — — \ E 212581.36 TS' RCP STUB AND PLUS io+40 6 U0� 10+� 19 RCP STORM K STA 11+39.6� STORM K2 STA 10+00.0 5' r STMH N 107504.54 E 212550.21 STORM MAIN K tl NOTE: ALL STORM SEWERS ARE PRIVATELY OWNED AND MAINTAINED STORM LAT K 1 (PRIVATE) 920 ��. W a inM bn 2: Wln � CSC �ffi nv n n&FSS P a -�x�Ak�JI r�m1IW sagl �F> 8'O 91 Cn52VC CR GIE 912 FINISHED GAD, 'S `tom ORIFIC W/ 31 90 20.) LF 18' e S.TOIt 25.9 V leROR 9w 9+80 10+00 10 20 PLATE 'r ORIFICE STORM LAT K2 (PRIVATE) " 8 aR $ - R m 920 gy N NN WK��9e 91 FINISHED CX/SONG GAO! GAGE 912 `1�-YN HGL ORFICE PLATE W/ T9^r ORIFICE 9oa 173 lF 18' 30.1 IF 18' pa, O .GP 10; 05�1.0fE 90 9+80 f0 00 10 20 10 40 20 10 0 20 HORIZONTAL SCALE I 1 " = 20' VERTICAL SCALE: I 4' CALL UTILITY NOTIFICATION CENTER OF COLORADO 811 CALL 2-BUSNESS DAYS IN ADVANCI BEFORE YOU DIG, GAGE, OR ERCAVATI. FOR THE MARKING OF UNDERGROUNL MEMBER UTILITIES NOTES Y m 8�p jjI�♦�N a^ V lAS @rpm _ p9 = Q K � 40 5 Z gm HOtn a :DEDC) O 4 W SOU(0 W O Z O aa. O 0—rn W Z n J IL f WUZ Z a�O & cj0a m In LL m 1. ALL STORM SEWER AND WATER CONSTRUCTION. AS WELL AS POWER AND OTHER "DRY" UTILFTY INSTALLATIONS. SHALL CONFORM TO THE CT' OF FORT COLLINS STANDARDS AND SPECIFICATONS CURRENT AT THE DATE OF APPROVAL OF THE PLANS BY THE LOCALENGINEER. 2. STORM SEWER PIPE SHALL BE RCP OR PVC (E� �+ WITHWATERTGM JOINTS AS SPECIFIED ON 'Z THE PLAN. ALL STORM SEWER 5HALL BE INSPECTED BY THE CRY OF FORE COLLINS, 3. LENGTH OF PIPE 15 MEASURED FROM CENTER ,• OF STRUCTURE TO CENTER OF STRUCTUREAND INCLUDES THE FLARED END SECTION. Q 4. NORTHING AND EASTNGS AND STATONINGS �} ARE CENTER OF STRUCTURE UNLESS L OTHERWISE NOTED. O 5. SEE ARCHITECTURAL DRAWINGS FOR WALL u LOCATION DETAILS OF GAS METERS. ELECTRIC METERS,ANOTT! EPHONETERMINALS. W .W.^ B. LIMITSOFSTREETCUTSHCVI VI APPROXIMATE. FINALLIMII'SARETOBE wT DETERMINEDIN THE FIELD BY CITY ENGINEER Z N Y11 INSPECTOR. ALLREPAIRSTOSEIN EP EFTRAIR T ACCORDANCE%VYMCIT'STR L W O STANDARDS. O T. ANY DAMAGED CURB. GUTTER AND SIDEWALK Q EXISTING PRIOR TO CONSTflUCHON. AS WELL G CTS. AS STREESIDEWALKS. CURBS AND GUTTERS. DESTROYED. DAMAGED OR REMOVED DUE TO IL CONSTRUCTION OF THIS PROJECT. SHALL BE O REPLACED OR RESTORED TO CITY OF FORT COLLINS STANDARDS AT THE DEVELOPERS U EXPENSE PRIOR TO THE ACCEPTANCE OF COMPLETED IMPROVEMENTS AND/OR PRIOR TO THE ISSUANCE OF THE FlRST CERTIFICATE OF OCCUPANCY. B. SEE UTILITY PLAN FOR GUTTER BOUNDARY O COORDINATES. 2 i n O N II Q p N W f 0 0 r pp t CC C w W wZ u a Q < M w u CITY OF FORT COLLINS. COLORADO O UTILITY PLAN APPROVAL RED, APPROVED: CITY ENGINEER DATE Ip pC, y Q CHECKED BY:� 34288 WATER ! WASTEWATER UTILITY DATE. W CHECKED BY: f�IONAL S70RMWAMR UTILITY DAIS E CHECKED BY: _ PARKS A REGEATION DAIS PIROJ. NO. 125HMO 6 1 CHECKED BY: TRAFFIC ENGINEER DATE 9 CHECKED BY: ENWRONMENTAL PLANNER DATE I I I I 1 I 1 I I 1 I AS -BUILT SURVEY LOTS 3,4 AND 5 OF HARMONY COMMONS, LOCATED IN THE NORTHWEST QUARTER OF SECTION 4, TOWNSHIP 6 NORTH, RANGE 68 WEST OF THE 6TH PRINCIPLE MERIDIAN, CITY OF FORT COLLINS, COUNTY OF LARIMER, STATE OF COLORADO SI $in -_a O D Gov 1 r; i n .Ii'RWR m.y. IND. 0 �; rnrpU L6 R O 1/ d Ip..uWYry � 0 0 JG' SO' I — lIYUV R.Y 110 N I �I b u1 . •N'l IR Nv ! ..9p3 M 'F-•\ [B RN ..pl].% G Rw . •911.M by - .910.R N. It.Un [n PIY . •91..00 SYN. RU • 4912 Ixv • .p10.0> wV N • .pDa S. IN .1110113 $lYN YY _ .NJl1 O RN • .11a.9 MV • .9x./a Mr. •no Ja • r I IN'. • Vlpll 1 ' r— a I AR R isR p I sTYN RY • .vu+, I I pp��Nv''.�•c. 1-: sYw w • •v1J l� W- Y • •W9.91 ..M..% - W 1902.79 SSYN IW - •91aM ' 4905.91) 1. N ..9M.91 • I NV TIN ..9GI.T. N...MBH i IrY 11RYCIy11( i0P . .91 J6� •It91,. [j I M\ �I +1 • MWJ pN _ . W : ..9p995 n , w: Dam NV N .4901 YID Ir NV [ 9 .V19.11 NV W ItNIO1.S9 N• S • "A O �r1 •+•Q ,% INV N . 19011.11 (/' STY 0140 11 ..91).B9 -•• �/ ' S,Y INLET q..9,2 90/ IN...0 l9.$. ITS 91, } . . [- 1L5 • .,11 20 S\w AN ..Na99 RNV ..K! N _ ST. wY ..91J.1 W: N - .,a,, OR RN It NIS S• J I III L - •pL121 n 71 S. IIY .91a11) • N. N.:q_•.F, IN wv W . aqT$$ \ I I .1v uc 12 �" !lY wµt 1L - .91 ).91 S1YN RY . HI3.9 N:. ayq 01 w...wM 19 I - it TINIH RY • .913 )9 6AM Not - .911T MV Y • 11111. 91 N. S..90)91 Y STW NM . "Ilm `Lr NV N • .9M r N...K29] STY ft , IN. . dy.Y..i tS lTYN DIN Da "' ) •YpR ll S,NITARY AND STORH DET;JL n �j fry .C' 0 40' so' SPIN WY It Mir" 9N R It MIOLST MY L • 490147 __ MV W ..90a[l M WAiLEGEND - r Ft HYDR.NI C S.INII•RT M/NHOLE P CLEAN OUT G AREA DRAIN ® STORMDRAIN MANHOLE 0 LIGHT ROLE ,` i ia..P.ing Nra[Sm•.yx4.'x0,s Ly.[N.D u ,'�N,YNvp"p'd[c, ;yIwN C(1N'xM.-I .A,YO CrnWo R•ppw.4lV h PNM [!$UNu LYq !IR !.M • ( W[ ON �[Juh r .• wu LYIC so: ..w, uc A • ti/ �. 1•p W�s•�• i� rLYAt lAR9� I NOTICE' ACCORDING TO COLCRADO L',W YOU MV;T COMMENCE ANY LEGAL ACTION BASED [F]N ANY C_rECTS IN THIS CONOOMNIUM MAR WITHN THREE YEARS NTER YCV FIRST DSCC AR SUCH DEFECT. IN NO E'.ENT, MAY ANY ACTION BASED UPON ANY DEFECT IN THIS 'UR: EY BE CCt1MENCED MORE THAN TEN YEARS AFTER THE DATE OF THE CERTIFIC+TION SHOWN HEPZON. AS-911LT E1EW.11M1$ APL [AW W AS-9VIL1 SNNLT aF THE sIIE FWOIOm ON OCIORCP )., =0 s /` Washburn www.WashburnSurveying.com �N1W �� SURVEYING 4025 Automation Wa • Suite C4 FOT't COi1111S, CO 80525 LAND 970-232-9645 ShMR l 01 I Pnjen 1: OO,bO'{5 D.1e: IARTaT. a,, a91T lnM: i =]9' DNbn: CDB APPENDIX D WATER QUALITY AND LID INFORMATION WE ,mi Qi$Ma,RiOMq YU New lmpemo,a SRa 11.JN aue/fgll ReWiRO MnlmumlmpervRu+AreirOM iRileE ]0,®i MR/aq. h. ..Of PeverYOlgn a11Ba31N all a,613 xrt/+qh xn Paromem amald PawrYmon.. san a .h rc imarviga:TRi lnee ey uD urvemem enmem M•Inaenmemo,r.Psvaeml ,an xrc/w. n. 9Wl za 4rea oeVmrYaion a}I6ISrN a}I a,6a9 airs/y, h. Prvemed areilgr Paver Yillon a] &W] a[RA,ft. 1.9 us4rea lrtalea 401me1mem MelMa al lPerviaur Vavnmenr 5v+,eml 1}.DO anelf .h. 3.6 ldal mtlery of grey lneleE 3D,9M we/iq.11. Adf%Orv9te lmate by VD )a% E%Pwau, Pwemem Re NewPMmpre.R. ]/.A) Kr Neq,rvee Mnimum 4e.Ol roroui Paaemem M t, 694 Nehv.h •ree of Paver Ynion a3 a,Bll a[m/,q. h. Tread Parer YAion tl} •y e[ 1, Paveme-m—Arra iou.1% 9,i6] eae/p.11. f Taaa x OI Pmou: P.oemmr Prmrmea 3e x i LEGEND 60 30 O 60 120 SCALE'. 1"- 6C' HARMONY COMMONS SECOND FILING - LOT 2 LID EXHIBIT PAVEMENTAREA TREATED BY LID OTHER IMPERVIOUS AREA TREATED BY LID AREA OF PAVER SECTION LID Table 50% On -Site Treatment by LID Requirement New Impervious Area Required Minimum Impervious Area to be Treated Area of Paver Section #1 (BASIN Kl) Pavement area for Paver Section #1 Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) Area of Paver Section #2 (BASIN K2) Pavement area for Paver Section #2 Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) 41,768 20,884 4,813 9,478 9,478 4,649 8,867 12,040 acre/sq. ft. acre/sq. ft. acre/sq. ft. acre/sq. ft. acre/sq. ft. acre/sq. ft. acre/sq.ft. acre/sq. ft. Ratio 2.0 2.0 1.9 2.6 Total Impervious Area Treated 30,980 acre/sq.ft. Actual % On -Site Treated by LID 74 % 25% Porous Pavement Requirement New Pavement Area Required Minimum Area of Porous Pavement Area of Paver Section #1 Area of Paver Section #2 27,807 6,952 4,813 4,649 acre/sq. ft. acre/sq. ft. acre/sq. ft. acre/sq. ft. Total Porous Pavement Area Actual %of Porous Pavement Provided 9,462 acre/sq. ft. 34 % II ' FLOW REDUCTION CALCULATIONS BASED ON PAVER VOLUME Rational Volumetric (FAA) Method OVERALL 100-Year Event ' LOCATION: RCS 2 Basin KI Paver Area 4813 It PROJECT NO: 1254-045-01 Void Depth 1 It COMPUTATIONS BY: es 300; Void 1444 cf DATE: 7r8rO17 Eauations: Area trih. to pavers = 16629 sf Developed flow = % = CIA C (100) - 0.89 Vol. In - Vi - T C I A - T OD Developed C A = 14758 sl Vol. Out . Vo =K Om T Release rate, Oro : 0.4 cfs storage = S - Vi- Vo K = 0.9 Rainfall intensity from City of Fort Collins OF Curve with (3.67') rainfall Storm Rainfall Oo Vol. In Vol. Out Storage Duration, T (min) Intensity, I (inlhr) (Flat Vi (ft') Vo (ft) S (tt) 5 9.95 3.4 1011 108 903 6 9.31 3.2 1136 130 1006 7 8.80 3.0 1252 151 1101 8 8.38 2.8 1363 173 1190 9 8.03 2.7 1469 194 1275 10 7.72 2.6 1569 216 1353 11 7.42 2.5 1659 238 1422 12 7.16 2.4 1747 259 1487 13 6.92 2.3 1929 281 1548 14 6.71 2.3 1910 302 1607 15 6.52 2.2 1988 324 1664 16 6.30 2.1 2049 346 1703 17 6.10 2.1 2108 367 1741 18 5.92 2.0 2166 389 1777 19 5.75 1.9 2221 410 1810 20 5.60 1.9 1 2277 432 1 1845 21 5.46 1.8 2331 454 1877 22 5.32 1.8 2379 475 1904 23 5.20 1.8 2431 497 1934 24 5.09 1.7 2483 518 1965 25 4.98 1.7 2531 540 1991 26 4.87 1.6 2574 562 2012 27 4.78 1.6 2624 583 2040 28 4.69 1.6 2669 605 2065 29 1 4.60 1.6 2712 626 2085 30 4.52 1.5 1 2756 648 1 2108 31 4.42 1.5 2785 670 2116 32 4.33 1.5 2817 691 2125 33 4.24 1.4 29" 713 2132 34 4A6 1.4 2875 734 2141 35 4.08 1.4 2903 756 2147 36 4.01 1.4 2935 778 2157 37 3.93 1.3 2956 799 2157 38 3.87 1.3 2989 821 2169 39 3.80 1.3 3013 842 2170 40 3.74 1.3 1 3041 864 1 2177 41 3.68 1.2 3067 886 2182 42 3.62 1.2 3091 907 2183 43 3.56 1.2 3112 929 2183 44 3.51 1.2 3139 950 2189 45 3.46 1.2 3165 972 2193 46 3.41 1.2 3189 994 2195 47 3.36 1.1 3210 1015 2195 48 3.31 1.1 3230 1037 2193 49 3.27 1.1 3257 1058 2199 50 3.23 1.1 3283 1080 2203 51 3.18 1.1 3297 1102 2195 52 3.14 1.1 3319 1123 2196 53 3.10 1.1 3340 1145 2195 54 3.07 1.0 3370 1166 2204 55 3.03 1.0 3388 1188 2200 56 2.99 1.0 3404 1210 2194 57 2.96 1.0 3430 1231 2199 58 2.1 1.0 3490 1253 2237 59 2.89 1.0 3466 1 1274 2192 60 2.86 1.0 3488 12961 2192 Storage Volume for Design 1 2237 W 7-28-17 FAA POND PAVER FLOW REDUCTION 1FT DEEP.xls.HTP K1 Paver K1 Proposed Detention Pond - Stage/Storage LOCATION: Harmony Commons, Lot 2 PROJECT NO: 1254-045-01 ' COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 8/ 10/2017 ' V = 1/3 d (A + B + sgrt(A'B)) where V = volume between contours, ft3 d = depth between contours, ft A = surface area of contour Stage (ft) Surface Area (ftz) Incremental Storage (cf) Total Storage (cf) 13.4 0 13.77 6480 799.15 799.15 13.8 7005 202.22 1001.37 about 4.5" ponding above pavers 7-28-17 orifice.xls ' BASIN K1 100-yr Event, Outlet Sizing LOCATION: HARMONY COMMONS, LOT 2 ' PROJECT NO: 1254-045-01 COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP ' DATE: 7/28/2017 Submerged Orifice Outlet: ' release rate is described by the orifice equation, Qo = CoAo sgrt( 2g(h-Eo)) where Qo = orifice outflow (cfs) Co = orifice discharge coefficient g = gravitational acceleration = 32.20 ft/s Ao = effective area of the orifice (ft`) ' E. = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) Qo = 0.40 cfs outlet pipe dia = D = 18.0 in ' Invert elev. = 4909.19 ft (inv. "D" on outlet structure) Eo = 4912.83 ft (downstream HGL for peak 100 yr flow - from FlowMaster) h = 4913.77 ft - 100 yr WSEL ' Co = 0.65 solve for effective area of orifice using the orifice equation ' Ao = 0.079 ft` 11.4 in` orifice dia. = d = 3.81 in ' Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering) d/ D = 0.21 ' kinematic viscosity, v = 1.22E-05 ftz/s Reynolds no. = Red = 4Q/(7rdv) = 1.32E+05 Co = (K in figure) = 0.65 check ' Use d = 3.75 in Ao — 0.077 ft` = 11.04 /n - ' Qmax = 0.39 cfs ' K1 orifice - 100yr, 7-28-17 orifice.xls FLOW REDUCTION CALCULATIONS BASED ON PAVER VOLUME Rational Volumetric (FAA) Method OVERALL 100-Year Event ' LOCATION : BUS 2 Busin K-' Paver Area 4649 ft PROJECT NO: 1254-045-01 Vold Depth 1 a COMPUTATIONS BY. es 30%Void 1395 cl DATE 7282017 ' Eoualions; Area trib. to pavers = 17974 sl Developed flow . Oo = CIA C (100) - 0.97 Vol. In . Vi = T C A - T Oo Developed C A = 17435 sf Vol. Out - Vo -K Opo T Release rate, Opo = 0.9 cfs storage -5-Vi-Vo t K= 1.0 Rainfall intensity from City of Fort Collins OF Curve with (3.67") rainfall Storm Rainfall Do Vol. In Vol. Out Storage Duration, T (min) Intensity, 1 (irVhr) (cfs) VI (tt') Vo (tt') S (tt') 5 9.95 4.0 1195 270 925 6 9.31 3.7 1341 324 1017 7 8.80 3.5 1479 378 1101 8 8.38 3.4 1610 432 1178 9 1003 3.2 1736 486 1250 10 7.72 3.1 1854 540 1314 11 7.42 3.0 1960 594 1366 12 7.16 2.9 2063 648 1415 13 6.92 2.8 2160 702 1458 14 6.71 2.7 2256 756 1500 15 6.52 2.6 2349 810 1539 16 6.30 2.5 2421 864 1557 17 6-10 2.4 2490 918 1572 18 5.92 2.4 2559 972 1587 19 5.75 2.3 2624 1026 1598 20 1 5.60 2.2 1 2690 1080 1 1610 21 5.46 2.2 2754 1134 1620 22 5.32 2.1 2811 1188 1623 23 5.20 2.1 2872 1242 1630 24 5.09 2.0 2934 1296 1638 25 4.98 2.0 2990 1350 1640 26 4.87 1.9 3D41 1404 1637 27 4.78 L9 3099 1458 1641 28 4.69 1.9 3154 1512 1642 29 4.60 1.8 3204 1566 1638 30 1 4.52 1.8 1 3256 1620 1 1636 31 4.42 1.8 3291 1674 1617 32 4.33 1.7 3327 1728 1599 33 4.24 1.7 3360 1782 1578 34 4.16 1.7 3397 1836 1561 35 4.08 1.6 3429 1890 1539 36 4.01 1.6 3467 1944 1523 37 3.93 1.6 3492 1998 1494 38 3.87 1.5 3532 2052 1480 39 3.80 1.5 3559 2106 1453 40 1 3.74 1.5 1 3593 2160 1 1433 41 3.68 1.5 3623 2214 1409 42 3.62 1.4 3651 2268 1383 43 3.56 1.4 3676 2322 1354 44 3.51 1.4 3709 2376 1333 45 3.46 1.4 3739 2430 1309 46 3.41 1.4 3767 2484 1283 47 3.36 1.3 3792 2538 1254 48 3.31 1.3 3815 2592 1223 49 327 1.3 3948 2646 1202 so 3.23 1.3 3878 2700 1178 51 3.18 1.3 3895 2754 1141 52 3.14 1.3 3921 2808 1113 53 3.10 1.2 3946 2862 1094 54 3.07 1.2 3981 2916 1 D65 55 3.03 1.2 4002 2970 1032 56 2.99 1.2 4021 3024 997 57 2.96 1.2 4052 3078 974 58 2.96 1.2 4123 3132 991 59 2.89 1.2 4095 3186 909 60 1 2.86 1 1.1 4121 1 3240 881 Storage Volume for Design 1 1642 tt' 7-28-17 FAA POND PAVER FLOW REDUCTION 1 FT DEEP.xIs,HTP K2 Paver K2 Proposed Detention Pond - Stage/Storage LOCATION: Harmony Commons, Lot 2 PROJECT NO: 1254-045-01 COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 8/10/2017 V = 1/3 d (A + B + sgrt(A*B)) where V = volume between contours, ft3 d = depth between contours, ft A = surface area of contour Stage (ft) Surface Area (ft2) Incremental Storage (cf) Total Storage (cf) 13.2 0 13.46 2944 255.16 255.16 13.7 5662 1015.11 1270.27 about 3" ponding above pavers 7-28-17 orifice.xls BASIN K2 ' 100-yr Event, Outlet Sizing LOCATION: HARMONY COMMONS, LOT 2 ' PROJECT NO: 1254-045-01 COMPUTATIONS BY: es SUBMITTED BY: INTERWEST CONSULTING GROUP ' DATE: 7/28/2.017 Submerged Orifice Outlet: ' release rate is described by the orifice equation, Q. = C(,k sgrt( 2g(h-E,,)) where Qo = orifice outflow (cfs) ' Co = orifice discharge coefficient g = gravitational acceleration = 32.20 ft/s Ao = effective area of the orifice (ft`) ' Eo = greater of geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) tQo = 0.90 cfs outlet pipe dia = D = 18.0 in ' Invert elev. = 4909.39 ft (inv. "D" on outlet structure) Eo = 4913.09 ft (downstream HGL for peak 100 yr flow - from FlowMaster) h = 4913.46 ft - 100 yr WSEL ' Co = 0.65 solve for effective area of orifice using the orifice equation ' Ao = 0.284 ft` 40.8 in` orifice dia. = d = 7.21 in Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering) d/ D = 0.40 kinematic viscosity, v = 1.22E-05 ft2/s Reynolds no. = Red = 4Q/(7cdv) = 1.56E+05 Co = (K in figure) = 0.65 check Use d = 7.25 in A, = 0.287 n` = Qmax = 0.91 cfs 41.28 in` K2 orifice - 100yr, 7-28-17 orifice.xls Project Nome: a4 �AA 4e7^/ Project No.: Client: Subje&. Date: By: yyith: 1 �,- _. -- 4' :d9C.AC. 11�5`11vvd j (o f I 1218 W. ASH, STE A • WINDSOR, COLORADO 80550 TEL.970.674.3300 • FAX.970.674.3303 APPENDIX E EXCERPTS FROM REFERENCE REPORTS E ' City of Ft. Collins ed Plans Approved By ' Date 5-I1-/6 ' FINAL DRAINAGE REPORT ' Harmony Commons Subdivision 1 ' Prepared for: Brinkman Partners ' 3528 Precision Drive, Suite 100 Fort Collins, CO 80528 (970)667-0954 Prepared by: Interwest Consulting Group 1218 West Ash, Suite A ' Windsor, Colorado 80550 (970)674-3300 ' March 11, 2016 Job Number 12544M5.00 ARm flora T wm. � IAiOV�D IA�FI M(KARm (AaFI \YIFL PTt NOCV (A4FI •tDO DCTFNTIDN Porn 4omu 1zTe 1zn atKH.TO 1.59 N eCIAL 1••1m D® 1)POND IN (COMBINED SWARM PONDS f01. m,a m1) HAS BEEN SIZED TO PROVIDE WATER QUALITY AND DETENTION FOR 41LW ACRES, INCLUDING THE 21.06 ACRES (BASINS 14) FOR ONSRE AND OFFSME BASINS SHOWN IN THE HTP i ROADWAY AND UTILITY INFRASTRUCTURE PROJECT. AS WELL AS THE REMAINING, EXISTING BASIN AREAS 7n CONTAINED VATHBN SAIAM BASINS 401. M. AND 601 OF THE HTP MASIERPMN REPORT, AND THE REMMMNG o EASTERN HALF-IMOTH OF OF TECHNOLOGY PARKVYAY ' (TOTAL OF 0.0 ACRES). THEREFORE, POND IDOWILL REPLACE AND PROVIDE DETENTION AND WATER DUALITY FOR WHAT WAS PREVIOUSLY SHOWN AS PONDS 101. 600, AND NI OF THE HTP MASTERPLAN SWAM MODEL TO ALLOW FOR FUTURE DEVELOPMENT OF THE REMAINING PARCEL AREAS. AT A LATER DATE D 2) FUTURE DEVELOPMENT ALONG THE FAST SITE OF TECHNOLOGY PARKWAY(SOUTH OF TIMBERVWIOD DRIVE) SHALL CONVEY RUNOFF FROM THE EASTERN HALF-VAD1TI OF TECHNOLOGY PARKWAY EAST AND IN TO POND ISO. O ])1W0 A STRUCTURES ARE PROPOSED FOR POND W TERNATER IOE THEEASTERN THE LL OUPROVIDE ANT CONTROLLED RELEASE RATE OF 12 C S (PER HTP MASTERPLAN SWUM RELEASE MODEL FOR PREVIOUS POND B01) THE 1YE91EAN OUTLET STRUCTURE WALL PROVIDE FOR A CONTROLLED RELEASE RATE OF 5 CFS (PER HTP MASTERPLAN SWARM MODEL FOR CHECKED BV: JOmd PREVIOUS POND 101) THE DRAINAGE BASNS SHOWN ON THIS EXHIBIT ACCOUNT FOR 21.0 ACRES OF TOTAL ONSME DESIGNED BT: AWiakn® AND OFFSITE BASIN AREAS ATTRIBUTABLE TO 1—HTP SIXTH FILING. THESE BASIN AREAS. ALONG WITH RATIONAL CVALUESSHOWMSELOWANDINTHERATIONAL DLkWN BY: A1Vi0® CALCULATIONS HAVE BEEN UTILIZED TO SIZE THE STORM SEWER INFRASTRUCTURE SHOWN IN THESE PUNS AND THE HTP INFRASTRUCTURE IMPROVEMENTS PROJECT, AS WELL AS TO SIZE SWALE A FOR THIS PROJECT FUTURE DEVELOPMENT OF BASINS 1 AND 6 SHALL MEET THE Box IMPERVIOUS RATIO FOR THE SAID BASINS ('O VALUES FOR FUTURE DEVELOPMENT SHALL ADHERE TO CORRESPONDING IMPERVIOUS RATIO OF M IMPERVIOUSNESS, NOT IV VALUE OF 0.00). SHOULD THE DEVELOPED CONDITION OF BASINS I AND 6 EXCEED AN ►/x 00%IMPERVIOUSNESS RATIO. ADDITIONAL WATER WALTTY V, AND DETENTION WILL BE REWIRED. BEYOND THAT SHOWN IN THE IMP SW66M MODEL 4) IN THE INTERIM CONDITION, BASINS I AND 6 WALL REMAIN IN THEIR HISTORIC CONDITION, WHICH IS EXISTING, O PLANTED AGRICULTURAL FIEIAS. FUTURE DEVELOPMENT O SHALL PROVIDE FOR THE ENTIRETY OF BASBNS 1 AND 6 Q BEING CONVEYED TO THE PROPOSED STORM DRAINAGE i Q INFRASTRUCTURE, SHOWN IN THIS PLAN AND CONTAINED a. VMTHIN THIS PUN SET. FOR B ATTR®UTASIE B AND THE CORRESPONDING DESIGN PONT FOR EACH L BASIN, O wLMIWM W 6) THE INTERIM COBBLE PTITVDISCHARfSE POINTS(LOCATED O I SOUTH OF TWBEITWOOD DRIVE) ARE PROVIDED FOR THE N INTERIM CONDITION ONLY. UO AND BMP MEASURES FOR BASINS 1 THROIK;H 10 SHALL BE PROVIDED BY OTHERS u Z oom�mo oo��mm oommmo 00000 so�m�o !oommm® �00�00m WITH FUTURE DEVELOPMENT. O 6) SEE RATIONAL METHOD CALCULATIONS FOR COMBINED ATTENUATED FLOW FROM COMBINED BASINS FOR STORM SEWER SWALE SONG, 7)17 OF CCOT CLASS ONGOING MATERIAL SHALL BE PLACED UNDER ALL RIPRAP SHOWN. ALL RIPRAP SHMl BE COVERED WITH 6. OF TOPSOIL B) SEE SWEET ASP2 FOR MASTER LEGEND. 6) FUTURE DEVELOPMENT EAST/ SOUTHEAST OF THE REGIONAL DETENTION POND SHALL BE DESIGNED TO ly L O IMI� F+6 U O (L. m w,^ V Q ENSURE A POSITIVE OVERFLOW PATH TO THE EAST AND INTO LADY MOON DRIVE O City of Fort Collins, Colorado Nr UTILITY PLAN APPROVAL APPROVED: Cry Erlginmr Dots Z O LEGEND CHECKED BY: water a wastewater Utifity Dote DRAINAGE BASIN BOUNDARY LINE PROPOSED DRAINAGE BASIN ID ACRESIC'VALUE CHECKED BY: St..Wer Utility Date � V.' Z CHECKED Bf: W 1 Q PROPOSED DRAINAGE DESIGN Parts a Recrealion Dote O POINT CHECKED BY: Traffic Engineer DNB PROPOSED DRAINAGE FLOW PATH CHECKED BY: A —105— PROPOSED INDEX CONTOUR-6 FT INTERVAL Em"wanW Pbvmr pate 0 yRIc�E THESE PLANS HAVE BEEN REVIEWED BY THE LOCAL — 106 — PROPOSED INTERMEDIATE CONTOUR-1 FT INTERVAL ram, — 4910 — EXISTING INDEX CONTOUR-5 FT INTERVAL ENTITY FOR CONCEPT ONLY. THE REVIEW DOES NOT — — 4911 — — EXISTING INTERMEDIATE CONTOIR-I FT INTERVAL INPLY RESPONSIBILITY BY THE RENEWING DEPARTMENT, THE LOCAL ENTITY ENGAIM. OR THE A LOCAL ENTITY FOR ACCURACY AND CORRECTNESS OF _y ` /ONALE J THE CALCULATIONS. FURTHERMORE. THE REVIEW DOES CALL UTIUTYNOTIFICATION NOT IMPLY THAT QUANTITIES OF ITEMS ON THE PLANS CENTER OF COLO.RTADO ARE THE FINAL GIIANTMES REQUIRED. THE REVIEW 1-800-922- 1987 SHALL NOT BE CONSTRUED IN AM REASON 5 d �' Io ZIG ACCEPTANCE OF FIFLWCIA- RESPONSIBILITY BY THE uNLN PRnFsenn N/WNLF eta a wRAOluvAre LOCAL ENTITY FOR ADDITIONAL OUANTITIES OF AEON$ SHOWN THAT MAY BE REONRED DURING THE SHEET NO: ASF'6 CONSTRUCTION RASE. 6 OF 9 �#—E amw STORM ODTLPT Jr LEGEND —(a,$)— 005TNBNmLaoNTOUR-5tTNTEnvAL lijOS----{4a,e)----00STWWrUVAMTBLbMOIR•,F7NERVAL L ,BD BNNM BIIBN i-,r-.�.� �•_A:. ei+'":"r � PiGq{M:'-`�C:`z. ffw�- 100 �IOMI P01L~ - ,..err .. �EXISTBK72C'STORM.' - _. .TO BE ABANDONED F201 MODE PROPOSED 48' STORM O USBABN CO NETWN \ 'm NO,NNB MMIAENT BASWMMARY ■•'rsi6ff �r'gaf?;iL=f :�•LY�L�.Pii�;��'il:•ltiiNT.i� ■ �;r.�..L,��sLIrI:�iAI:>•S6•:�SSL�SSGIi'.S ■ tyLi■e= R,��tS3LR�f ib\�iFli i.�f.'i��'iG[.i ■=..,.ip9S■t .�W�:.)•tS.�::L 1:Lf�'�'j�i:L�[t.ILiiil.i !•iif■4S■ �!'I Il[16s1 t�i�&hfl�S'Lae3s iRiL>• iRd �' ■'..l`.ul: �;7 L=Fh5di7tS�7Li4:��•�i�L �),[E;:fiilSii[„� EXISTING 30'. STORM !ffiil� I III�� lllill� Illllla -T L rr-e EXISTING Sr X Sr EWPTrALSTORM ORM 0 0 o� I MGM NOLLVL. CONBLRLCTM P.14., . lemom N4 Msis ]LIY.LYlC1-N-00 I DNBgNB SWMM Reltb Shed Id+ ZL Z ((Iwo ;rj 2w cc. X 0 u no to m 0 CV)