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HomeMy WebLinkAboutDrainage Reports - 11/16/2005 (7)P OPOtTy OF FORT CO S uT-n1Tm FINAL DRAINAGE & EROSION CONTROL REPORT FOR SERRANO TOWNHOMES r i I [J a FINAL DRAINAGE & EROSION CONTROL REPORT FOR . . SERRANO TOWNHOMES It FINAL DRAINAGE & EROSION CONTROL REPORT FOR SERRANO TOWNHOMES Prepared for: TREADSTONE DEVELOPMENT 231 S. Howes Street Fort Collins, CO 80522 Prepared by: North Star _Design 700 Automation Drive, Unit I Windsor, Colorado 80550 (970)686-6939 October 19, 2005 Job Number 223-01 North Star va, design, inc. October 19, 2005 Basil Hamdan City of Fort Collins Stormwater 700 Wood Street Fort Collins, CO 80522-0580 RE: Final Drainage & Erosion Control Report for Serrano Townhomes Dear Basil, I am pleased to submit for your review and approval, this Final Drainage & Erosion Control Report for Serrano Townhomes. I certify that this report for the drainage design of Serrano Townhomes 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. Prepared by: SA4--Ie- 4z-7 Shane Boyle, EIT North Star Design, Inc. Reviewed By: 700 Automation Drive, Unit I Windsor, Colorado 80550 970-686-693.9 Phone . 970-686-1 188 Fax TABLE OF CONTENTS ' TABLE OF CONTENTS............................................................................................................... iii 1. GENERAL LOCATION AND DESCRIPTION 1.1 Location...................................................................................................................1 1.2 Description of Property............................................................................................1 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin rDescription..........................................................................................1 i 2.2 Sub -Basin Description.............................................................................................2 3. DRAINAGE DESIGN CRITERIA 3:1 Regulations..............................................................................................................2 3.2 Development Criteria Reference and Constraints....................................................2 3.3 Hydrologic Criteria....................................................................:.............................2 3.4 Hydraulic Criteria....................................................................................................3 4. DRAINAGE FACILITY DESIGN 4.1 General Concept ................................ 4.2 Specific Flow Routing.............................................................................................3 4.3 Water Quality Considerations..................................................................................4 4.4 Drainage Summary ...................................................................................................5 5. EROSION CONTROL 5.1 General Concept......................................................................................................5 5.2 Specific Details........................................................................................................5 6. CONCLUSIONS 6.1 Compliance with Standards....................................................................................6 6.2 Drainage Concept.....................................................................................................6 7. REFERENCES....................................................................................................................7 APPENDICES A Vicinity Map B Hydrologic & Hydraulic Computations C Water Quality and Erosion Control Calculations D Excerpts from Previous Reports ' E Figures and Tables iii GENERAL LOCATION AND DESCRIPTION 1.1. Location The proposed Serrano Townhomes is located in Fort Collins at the southwest corner of the intersection of South Lemay Avenue and Boardwalk Drive. This project is located in the Southeast Quarter of Section One, Township Six North, Range Sixty-nine West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. The site is bounded on the north by Boardwalk Drive, on the west by an existing private drive within the Hamlet development, on the south by the Mail Creek Ditch and on the east by South Lemay Avenue. See the Vicinity Map in Appendix A. 1.2. Description of Property The project consists of approximately 2.3 acres of land. The proposed improvements on this site consist'of 18 units in six buildings with associated drives, walks, and parking. Access is obtained on the north from Boardwalk Drive. No portion of the proposed project is within a designated floodplain area. Existing development on the site includes a single-family residence, along with drives and walks all of which will be removed with this project. Existing drainage patterns are to the north at approximately 4%. 2. DRAINAGE BASINS AND SUB -BASINS 2.1. Major Basin Description The proposed development lies within the McClellands Mail Creek Drainage Basin. Detention for this site is provided by a downstream detention pond...in the Lodge at Miramont. This detention pond is designated as Detention Pond 340 in the SWMM Model as shown in the "Final Drainage and Erosion Control Study for the Hamlet at �• Miramont P.U.D." by RBD; Inc., dated March 29, 1996 and the subsequent "Final Drainage Report for the Lodge at Miramont P.U.D. by TST Inc. dated March 13, 2001. Excerpts of these reports are included in Appendix D of this report. The existing outlet structure for the Miramont pond will also be retrofitted to provide extended water quality detention for both the existing Miramont development and the proposed Serrano Townhomes development. Refer to Section 4.3 of this report for a more detailed if narrative. 3. 2.2. Sub -basin Description The site currently drains from south to north, with an existing slope of approximately 4%. According to the RBD, Inc. drainage report, this site is a portion of Basin 212 of the SWMM Model. In the TST report, this site is included in Basin OS8. With existing drainage patterns, runoff sheet flows to Boardwalk Drive, then is collected in an existing Type R inlet, and then is piped to the existing detention pond. The proposed drainage scheme will incorporate the use of landscape drains to convey on - site runoff to the existing storm sewer in Boardwalk Drive. Perimeter drains will also be used to move groundwater away from the building foundations. The perimeter drains will connect to the proposed landscape drains and will be piped to the existing Boardwalk Drive storm sewer. No groundwater from this site will be discharged onto the surface. 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), 2001 has been used. 3.2. 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 Master Drainage Reports governing this site. Neither stormwater detention nor extended water quality detention are provided on this site but the required storage volume is provided in the Lodge at Miramont pond on the north side of Boardwalk Drive. The pond certification by TST is included in Appendix D. 3.3. Hydrologic Criteria Runoff computations were prepared for the 10-year minor and 100-year major storm frequencies utilizing the Rational Method. All hydrologic calculations associated with the basins are included in Appendix B of this report. Detention for this site will be provided by Detention Pond 340 located on the north side of Boardwalk Drive in the Lodge at Miramont. 2 ' 3.4. Hydraulic Criteria ■ All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria and are included in Appendix B of this report. There are no public storm sewer improvements proposed with this project. All storm sewers shown on site will be privately maintained by the homeowner's association. All basins will release into the existing curb and gutter of Boardwalk Drive or into the storm pipe that will tie into the back of the existing type R inlet in Boardwalk Drive. 4. DRAINAGE FACILITY DESIGN 4.1. General Concept The runoff from the proposed development will flow to the north to existing Boardwalk P P P g Drive via sheet flow and proposed private landscape drains. Runoff will be conveyed via Boardwalk Drive curb and gutter or on site storm pipe to the existing Type R inlet and ultimately to the downstream detention pond in the Lodge at Miramont. Based on the SWMM Model updated with the Lodge at Miramont development, this site was included in the sizing of the detention pond. The model assumes that Basin 212 (which includes this development) is 4.2 acres and has an imperviousness of 80%. Based on a composite calculation of the actual area in Basin 212, the imperviousness is approximately 57%. Therefore, based on the model and the actual conditions, adequate detention is provided in the existing Miramont detention pond. The existing outlet structure for the Miramont Pond will be retrofitted with this project in order to provide extended water quality detention. A detailed narrative is included in Section 4.3 of this report. 4.2. Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. Basin 1 (0.43 acres) is located in the western portion of the site. Runoff from this basin rwill be collected in the west proposed private storm pipe and conveyed, with runoff from Basin 3, to the inlet in Boardwalk Drive. Basin 1 runoff is 1.0 cfs for the 10-year minor - storm and 2.8 cfs for the 100-year major storm. i Basin 2 (0.60 acres) is located in the eastern portion of the site. Runoff from this basin will be collected in the east proposed storm pipe and conveyed to the inlet in Boardwalk Drive. Basin 2 runoff is 1.3 cfs for the 10-year storm and 3.5 cfs for the 100-year storm. Basin 3 (0.99 acres) is located in the interior portion of the site and encompasses all of the proposed drives and parking and a majority of the buildings. Runoff from this basin is conveyed through the site via curb and gutter and concrete pans. The runoff is conveyed to an inlet in the proposed drive entrance. The flow will be collected in the west storm pipe and conveyed with runoff from Basin 1 to the inlet in Boardwalk Drive. Runoff from Basin 3 is 3.2 cfs for the 10-year storm and 8.2 cfs for the 100-year storm. Basin '4 (0.09 acres) is located in the northwestern portion of the site. Runoff from this basin will sheet flow to the north and into the Boardwalk Drive curb and gutter. Runoff from Basin 4 is 0.3 cfs for the 10-year storm and 0.8 cfs for the 100-year storm. Basin 5 (0.18 acres) is located in the northeastern portion of the site. Runoff from this basin will sheet flow to the north and into the Boardwalk Drive curb and gutter. Runoff from Basin 5 is 0.5 cfs for the minor storm and 1.3 cfs for the major storm. ' 4.3 Water Quality Considerations The existing detention pond located in the Miramont development will be the ultimate outfall point for the Serrano Townhomes development. A v-notch weir was designed in order to provide extended water quality detention as a retrofit to the existing outlet structure. Since there is currently no existing structure to control water quality flow from the pond, the v-notch weir structure was designed per request by the city to control flow from both the proposed Serrano development and the existing Miramont development. The previously discussed basins were used to develop a total imperviousness for the proposed development. This imperviousness was found to be 53%.with a tributary area of 2.29 acres. The imperviousness for the Miramont development was taken from the drainage report for that area prepared by TST, INC. A composite area and percent impervious was calculated for.. the existing Miramont. development and the proposed Serrano. Townhomes development. The composite percent impervious used for this analysis is 57%, with a composite area of 12.30 acres. LI The extended water quality volume required for the composite area was calculated to be 0.233 acre-ft using the method detailed in the Urban Strom Drainage Criteria Manual. The water quality depth was calculated to be 0.36 ft above the permanent water surface. This depth was used as the design height for a v-notch weir for a minimum 24-hour release time. It was found that 3-45' notches were required at this depth to release the required water quality storage with a total release time of 30 hr. The outlet will also be retrofitted with a bar skimmer to prevent the accumulation of algae in the weir notches which could restrict the flow through the structure. Refer to Appendix C of this report for all extended water quality calculations. 4.4 Drainage Summary The proposed development has been divided into five subbasins. Runoff from all subbasins will be routed to the north and into the Boardwalk Drive curb and gutter or be collected in the on site storm drain and conveyed to the existing inlet in Boardwalk Drive. The runoff will then be piped to the existing downstream detention pond. 5. EROSION CONTROL 5.1 General Concept ' This site lies within the Moderate Rainfall and Wind Erodibility Zone per the City of Fort Collins Zone Maps. The potential exists for silt movement from the site and into the existing storm system during construction. Potential also exists for tracking of mud onto existing streets which could then wash into existing storm systems. 5.2 Specific Details To limit the amount of silt leaving the site several erosion control measures shall be implemented during construction. All inlets shall be protected with gravel filters, straw bales will be placed in the swale on the west side of the site and the west, north and east boundaries shall have silt fence installed. A vehicle tracking pad shall be used to control the mud being tracked onto the existing pavement in Boardwalk. During overlot grading, disturbed areas are to be kept in a roughened condition and watered to reduce wind erosion. i i The required performance standard for the site is 79.5%. Based on the effectiveness calculations, this performance. standard is not, being met, but adequate erosion control measures are being provided on this site. Any additional measures would not increase the effectiveness of the erosion protection but would increase the costs with no added benefit. All erosion control calculations are included in Appendix C of this report. Specific erosion control measures during and after construction are shown on the Drainage and Erosion Control Plan in the back pocket. The erosion control escrow amount is $10,410. 6. CONCLUSIONS 6.1 Compliance with Standards MAll computations that have been completed within this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual. 6.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for conveyance of stormwater runoff to the existing detention area. The private storm sewer system has been designed to adequately pass required flows and will be maintained by the Homeowner's Association for this development. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit would be required. r i 7. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March 1999. 3. RBD, Inc. Engineering Consultants, "Final Drainage and Erosion Control Study for the Hamlet at Miramont P.U.D.", dated March 29, 1996. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated September 2001. Q APPENDIX A VICINITY MAP I I I 7 PROJEC LOCATIO W z � w Q } o Q Ld W J I 0 O o 1 Q— r . 3 O o Z c O �O O D}: F - 7 \ 00 DATE: 10/19/05 SCALE: 1 " = 500' DRAWN BY: SB JOB NO.: 223-01 SERRANO SUBDIVISION VICINITY MAP GREEN$ awo North Star design, inc. 700 Automation Drive, Unit I Windsor, Colorado 80550 Phone: 970-686-6939 Fax: 970-686-1188 APPENDIX B HYDROLOGIC & HYDRAULIC COMPUTATIONS 0 a �c O C �F Y wU a a a N C O O O O U w w � Lq m � U o co O o 0 0 0 0 0 a U 7 0 e e o 0 o e E m a. M V1 V1 a .l 3 n h b r N a a a o Q N 0 W PQ+ FG Q `-' �p ♦p N � N N b T O N cQ. W U V Q F z Z � F N ¢ p � Z � V N 0 W U Q 1 U h O 2 w N m N V] N cn �O a ^ d ❑ rn v o 0 o r w 0 Uq a`�v � I N U u Y �a MQ 0 " r 06 d' N N ON a a G m M O O °% O^ z ° a --oM o0 H Vl •�\,,• ^' N N N 'wj s d eo•. OOO v� rnra�°o t+l V t+1 N N t+l F Za. ° 000'^o 0 v v1 v1 O O vt cq N N N �° V N a a o oo�nror z U o 0 0 0 0 0 U '.. M O °% Cl O O O O N Q e z En Q Q cn m z .... N M 7 0. c� c O rn � F- � O .-• N c>1 7 V1 V1 W 0. U ° s C P � N M > t�tl P U _ � o y } U ° U C c O E ¢+ i O li u u c w a d C � mv�000 �o W O 000 G M x\ v N N O O M U q a w w IY +� N U�^ y z a i C. O N 00 o 0 0 O O E �o r M o0 .a W 01 w -•� ovv,00 0 z Q Ir! o 00 00 �o a+ v w N N N Q o00 c0 �n W F M m O 'ct N 0 o r �n � N v v O V l " w O O� V W 7 G N M N F a o 0 0 ^ o 0 by N N N M (V ii h Vl 0 0 vt N N N N �D V N N � N O� V l� -•. r 0 0 0 0 o O U �? U M 7 O CO TG� QD O w G1 N ¢y V O O O O O N Q A Z� O W E.. to P Ln Q Q d �Z p�O o U p F O En O N M V v1 vi w Q U U c .N h � b N C x U m � yin II > 't7 R i--i N F. 3 aY + Q + 09 > a R, a w z a A a n U i � e 0 0, a ^ w a 0 > a VO •+1 N tl vt Q _ o 00 00 0o w Q � r oo vi vi vi o� Q Z U a `o < n n Q o e a a rn o w rn ry O O O O O N z z_ 0 F a o � � U ❑ 0-0 C 0 a 1► a� o � W N a7 N VJ N Cn �O z x _T V W 6 W V U � i e � 8 F 6 a � a 0 r x Q 0e .6 ao �n a a rn g .E O e r vi vi vi o0 zo U. 0000c o s G b rn Q V W O 0� N C O O O G lV Z O p. mz m � � N o m U Q 0 0 0 i 1 1 1 1 Actual % Impervious Basin 212. Boardwalk Drive W = 34 ft (1/2 R.O.W.) L = 1120 ft A = 38,080 SF = 0.87 acres . Paved Width = 29 ft (Including 4' attached walk) Landscape Width = 5 ft Paved Area = 32,480 SF Landscape Area = 5,600 SF % 1 = 85.3%. C = 0.85 Lemay Avenue W = 57.5 ft (1/2 R.O.W.) L = 335 ft A = 19,263 SF = 0.44 acres Paved Width = 35 ft Detached Walk Width = 6 ft Landscape Width = 16.5 ft Paved Area = 11,725 SF Walk Area = 2,010 Landscape Area = 5,528 SF . % I = 70.3% C = 0.75 Irrigation Ditch Bank A = 14,166 SF = 0.33 acres % I = 0% (No development on this parcel) C = 0.20 On -Site Basin A = 99,808 SF = 2.29 acres % I = 51.60% (From Flow spreadsheet) C = 0.61 (From Flow spreadsheet) Basin 212 Composite A = 171,317 SF = 3.93 acres % 1 56.9% C = 0.64 I� ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Major & Minor Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Project: Serrano Townhomes Inlet ID: 5' Type R Inlet TBACK TCROWN yy SBgC-� T, TMAX /I W -+ Tx ,Itl - Street Crown y Qw I Qx HCURB d \ S X a mum Allowable Width for Spread Behind Curb Slope Behind Curb (leave blank for no conveyance credit behind curb) ring's Roughness Behind Curb of Curb at Gutter Flow Line ce from Curb Face to Street Crown Depression Width - Transverse Slope Longitudinal Slope - Enter 0 for sump condition Tg's Roughness for Street Section Allowable Depth at Gutter Flow Line for Minor & Major Storm Allowable Water Spread for Minor & Major Storm Cross Slope (Eq. ST-8) Depth without Gutter Depression (Eq. ST-2) Depth with a Gutter Depression - ble Spread for Discharge outside the Gutter Section W (T - W) Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) .rge outside the Gutter Section W, carried in Section Tx rge within the Gutter Section W (Qr - Qx) rge Behind the Curb (e.g.. sidewalk, driveways, & lawns) mm Flow Based On Allowable Water Spread eoretical Water Spread _ ` - Theoretical Spread for Discharge outside the Gutter Section W (T - W) Gutter Flow to Design Flow Ratio by FHWA HEC-22 method (Eq. ST-7) -Theoretical Discharge outside the Gutter Section W, carried in Section Tx TH Actual Discharge outside the Gutter Section W, (limited by distance T,m) Discharge within the Gutter Section W (Qd - Qx) Total Discharge for Major & Minor Storm Slope -Based Depth Safety Reduction Factor for Major & Minor Storm Discharge Behind the Curb (e.g., sidewalk, driveways, & lawns) Maximum Flow Based on Allowable Gutter Depth TBncK = 0.0 ft SBACK = ft. vert. / ft. horiz nBACK = Hcuee= 6.00 inches TCROW1 - _20.0 ft a = = `1.00 inches W='- -1.00 ft Sx = ' ° 0.0200 ft. vert. / ft. horiz So = 0.0000 R. vert. / ft. horiz nSTREET- .;0.0150 Minor Storm Major Storm dmm= _' -.6.00 _,. - ,6.00 inches TKux = ; -�20.0 -20:0 ft Sw: y' d= Tx' EC: Qx' Qw: ABACK' QT: TTH Tx TH - Eo Qz TH' % Qw= Q= R- Q9ACK - ad= 0.1033 0.1033 4.80 4.86 '."5.80 . 5.80 19.0 19.0 .0A48 : .0,148 - 0.0 . 0.0 0.0 .. 0.0 0.0 0.0 SUMPI SUMP Uft nches niches t Is is :(5 :fs Minor Storm Major Storm 20.8 20.8 ft 19.8 19.8 ft 0.142 -' 0.142 - 0.0 - 0.0 = 0.0 -: 0.0 0.0 0.0 0.0 0.0 "SUMP SUMP SUMP SUMP :fs :fs :fs :fs :fs :fs Minor Storm Major Storm Qnmw= SUMP SUMP cfs UD-Inlet v2.02.xis, C-Allow 911/2005, 2:03 PM 18 16 14 N d 12 c c t w a m 8 0 v t 6 x 4 2 0 Street Section with Flow Depths 0 5 10 15 20 25 Section of 1/2 Street (distance in feet) UD-Inlet_V2.02.x1s, Q-Allow 911/2005, 2:03 PM -- - - -------- .......... INLET ---- . . ..... ...... ...... .... . .......... .......... .................. .... ... ... .. � .71 .... .... .. . .... . .......... Protect errano:Town orriesi. Inlet . ..... . .... .. . ........... ..... .. ....... . ..... .... .... ............ . ype:R Inlet Lo (C). Design Information (Inputl Type of Inlet Type = 0 Local Depression (in addition to gutter depression 'a'from 'Q-Allovv) inches Number of Unit Inlets (Grate or Curb Opening) No Grate Information Length of a Unit Grate L. (G) feet Width of a Unit Grate W. ...... Nhk feet Area Opening Ratio for a Grate (typical values 0.15-0.90) Amp Clogging Factor for a Single Grate (typical value 0.50) Cr (G) ... NIA' Grate Weir Coefficient (typical value 3.00) C. (G) ... AM Grate Orifice Coefficient (typical value 0.67) Ca (G) .... ........ ..... NIA Curb Opening Information Length of a Unit Curb Opening Lo (C) feet Height of Vertical Curb Opening in Inches inches Height of Curb Orifice Throat in Inches inches Angle of Throat (see USDCM Figure ST-5) ....... Theta 63A degrees Side Width for Depression Pan (typically the gutter width of 1 feet) Wp 1.00feet Clogging Factor for a Single Curb Opening (typical value 0. 10) C, (C) = -06 Curb Opening Weir Coefficient (typical value 2.30-3.00) = C. (C)2 30 ICurb Opening Orifice Coefficient (typical value 0.67) C. (C) = 0.67 Resulting Gutter Flow Depth for Grate Inlet Capacity in a Sumo Clogging Coefficient for Multiple Units Coef N /A.: Clogging Factor for Multiple Units Clog N/A: As a Weir Flow Depth at Local Depression without Clogging (0 cfs grate, 8.2 cis curb) d. N/A inches Flow Depth at Local Depression with Clogging (0 cfs grate, 8.2 cfs curb) dw, .. ....... N/A' inches As an Orifice Flow Depth at Local Depression without Clogging (0 cis grate, 8.2 cfs curb) du N/A' inches Flow Depth at Local Depression with Clogging (0 cfs grate. 8.2 cfs curb) d. - inches Resulting Gutter Flow Depth Outside of Local Depression d.-,. NIA inches Resulting Gutter Flow Depth for Curb Opening Inlet Capacity in a Sump Clogging Coeffic ient for Multiple Units Coef Clogging Factor for Multiple Units Clog 0.1 0 Curb as a Weir, Grate as an Orifice Flow Depth at Local Depression without Clogging (0 cfs grate, 8.2 cfs curb) d. �: , 789 inches Flow Depth at Local Depression with Clogging (0 cfs grate, 8.2 cis curb) cf, 8 2 inches Curb as an Orifice, Grate as an Orifice Flow Depth at Local Depression without Clogging (0 cfs grate, 8.2 cfs curb) cl, inches Flow le plilauLocal Depression with Clogging (0 cfs grate, 8.2 cfs curb) do, �. 8 9 3 inches Resulting Gutter Flow Depth Outside of Local Depression d.4.. inches Resultant Street Conditions Total Inlet Length 4� L feet Total Inlet Interception Capacity (Design Discharge from Q-Peak) :xX 8 2 ON Resultant Gutter Flow Depth (based on sheet Q-Allow geometry) d .3 inches Resultant Street Flow Spread (based on sheet Q-Allow geometry) T .... . ..:17.7.9 feet Resultant Flow Depth at Maximum Allowable Spread cISPR,,M . . . . . . . . . . 0.0 inches UD-InIet—v2.02.xIs, Inlet In Sump 9/l/2005,2:06 PM 30...................................................................................................................................................................................................... 29 28 27 26 25 z4 23 22 21 �1 20 G� 19 18 N N LL 17 9 A d 16 2 u) 15 N W C 14 L 13 a o" 12 n•' - 10 9 x x 8 7 6 5 3 2 i 1 0 0 2 4 6 8 10 12 1416 18 20 22 24 26 28 30 32 34 36 38 40 O (cfs) —{—Curt Weir 0 Curt Orif. —R—Not Used a Reported Design — 0 Reported Design Flow Depth (in.) Flow Depth (in.) Flaw Depth (In.) Spread (ft.) 9 LID-Inlet_v2.02.x1s, Inlet In Sump 9/1/2005, 2:06 PM [1 1 1 1 1 Scenario: Storm 1A V5 R5 I-6 P-6 al e a Title: Serrano Townhomes Project Engineer: Shane Boyle n:\223-01 serrano townhomes\drainage\storm 1a.stm North.Star Design, Inc. StormCAD v4.1.1 [4.2014] 06/22/05 07:12:17 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 t� IL q c0 0 O N O m J .-. fO0 O O c�0 O cN0 O 3= v v v v v v v 0 0 E m m m m N C m oU� c0 0 v M N N v 30 O O O O O CO (D jA «^ W 0) W 0 O O) 0) v a a U v v v v O O n m C9 ano w o o ano N O"r m N m co O co co O O O 0> s O m rn 0 rn rn M C C v a O E rn Ci� o Lq � o a1 J m co n O V m O O O O (D co co O C� w N = 0) (3 (31 Q) O) 01 01 n a a v v v v V E O 0 O n 0 0 m m O r O O O N O n ro LO y O` E 20 n U Of 0) O) W D) (8 v v v v v v v o m U.)) rn 0 0 m E O n or m ao n o CO m m ro cv0 m m cm cco > rn0)0>rn0)Om a— CIS v v v v Id:v v ID N a O O st N 0) r 'C r 0) co (D O N U N N 6 O ci a c0 6 > O 0) O O O O O — � v, M v M co o O MT v v v v cn o ro a 0.0 U� 0 0 0 0 0 0 0 o n v m o n N M M O y00, > a O_. 0) O O O O O O N O m Qf O) O) O O O o O O O O O O N Fn Old O v 6 6 (Ni O r m � J C O N U U U U U U U C C C C C C C mN N N N N N N w N E m N 6 c 0 Z 0 02 N O 0 0 — 0 N ` O N Z � N O lV N M n 0 r J a a a a a a a O O O A O n Cl) O N i ¢ . co co o. r O O H U e a Q) c U m� O a N-O r � O N Z 0 m` r cc N 0 O N l0 N m E� N m E N N O) r C a Vl N E N 0 O C.� O.¢ 3 o n 0 N C N nO d O 0 O 0 m N U N F C O C C N om o� m md ctv �. d 6 aEE r g m w o o 0 C o n 0 o 0 o o 0 0 0 0 0 0 0 0 0 0 0 C A mt0 fO t0 m v .rn a rn m atm Ci m rn d Y d d d C d d O O d 0 FI _n-�-1-F-17-1 F do OEE � CO C C A O O O m M N h lD (D mm o o,: Yce�� NO /a�doN� _ d O C C o �o N N b b d d � i(]L"L"OC dma�v,�a° c; W �6C NO J�OJN(n O O C C O � _ ro dd U —yccm tiO1 O �nC^NO O J�C1J fAN 0 e 1 i 1 1 1 1 1 1 1 i 1 i 1 1 1 1 Scenario: Storm 1 B .C,q s-f S 4 rM - Q1 P-13 J-3 SK J-2 ID Title: Serrano Townhomes Project Engineer: Shane Boyle n:\223-01 serrano townhomes\drainage\storm 1b.stm North, Star Design, Inc. StormCAD v4.1.1 [4.20141 06/22/05 07:17:05 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 0 0 N m O O O O O O O 0 0 o O O O O fV O of N O N 0 rn m rn rn me rn m O N 00? wm mm r ma' I aEt BIN n i i A e I I O? N m N01 31 10i < oE�n M' � c6 O O? O O aIO. E Jao3 C� OR ----Earn<—..—_ m� m MV H zE�a Jao7 C C om Ohm On mm mrn d 1 m W^ r JDOJtfltj ++ CC mm mrn L p� UN /a ddNNN 41�C1�1 Np�O m J7OJ01 (b M Iy 97 E O (D (D LL] (O N tD O 0 7 r a0 t+1 (0 r r 3 2 v v v v a v v v 0 0 E N O O N a th N l(1 (O 3 O O O O O O O O y rn rn rn rn rn rn rn rn a a v v v 3 U a v v O E O O (n v O r (D co (D v 0) (D (ap co (/1 v 0 a O 01 0 m 0 W C C V V a V ? 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StormCAD v4.1.1 [4.2014] ' 06/22/05 07:20:17 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 u el t7 N N N a Clw rn 0 o m 32 avaa 0 E rO (O O ((D co C .N N N N N (D (D co CO CO v W Q) W O) 3U 0 ❑ �r o d� 0) 0) (D 0 u! > � 07 0) O) 01 C C v 3— � 4� 4 O ❑ o 00 E o (D to r J _ O O) y = a) 0) E ry (r-: N C 3 ^ cq r m m m N 2 v co co 0 to y O m O 01 o.0 v v a v o 0 E CO. r n o N NN ^ to D (o (D to > 0) 0( (D 0) o.— m CA._ 0 m N O O > v % co O m � LO 7 Co rN.. co to co LL D. 0 f0 � U 0 O o 0 E CO 0 (O (n h 01 V a) O� aLL U) O ) V 0^ M O N r 0 O o O O, O v 00 m N (O V 7 N T O N CO CO R C N N r J C 0 0) L L L L U U U U C C C C_ (D (O N 00 N N m N N N 0 C O 3Z (D11O O E m d0 in O o. Z m a m co m LO (D -i aadd Profile Scenario: Base Label: J�3 Label: 1-3 Rimi4,957_,80 ft Surnp:4,961.01 ft -7 Rim:4,968.20 ft —Sul p:-4,962.7 ft 4,969.00 _ Label: Q1 I ' - 4,968.00 Rim:4,966.00 ft Sump: 4,960.90 ft - 4,967.00 - I _-.-_-- -_.---__. ----------------- -- 4,966.00 — 4,965.00 Elevation (ft) - 4,964.00 I 4,963.00 _—�—--- 4,962.00 4,961.00 ( — 4,960.00 0+00 . 0+20 0+40 0+60 0+80 1+00 1+20 1+40 1+60 Station (ft) Label: P-13 Label: P-16 Up. Invert 4,962.71 ft Up. Invert 4,961.01 ft Dn. Invert 4,961.01 ft Dn. Invert 4,960.90 ft L: 138.22 ft L: 14.95 ft Size: _12 inch Size: 21 inch S: 1.23 % S: 0.74 % r Title: Serrano Townhomes - Project Engineer: Shane Boyle n:\223-01 serrano townhomes\drainage\storm 1c.stm North. Star Design, Inc. StormCAD v4.1.1 [4.2014] 06/22/05 07:21:33 AM © Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: Base Label: 1-6Ri m::44,969.50 ft 1.70 ft Label : J -Label:-1-5 R m: 4,967 Rim: 4,967.80-ft- - Sump: 4,9E Label: 0-1 Rim:4,966.00 ft r4�61, Sump:4,960.90 ft n Label:P-16 0+00 0+50 1+00 1+50 2+00 Up. Invert 4,961.01 ft Station (ft) Dn. Invert 4,960.90 It L: 14.95 ft Size:21 inch Label: P-6 Up. Invert 4,961.70 ft Label:P-5 S: 0.74 % Dn. Invert 4,961.01 ft Up. Invert 4,962.80 It L: 76.13 ft Dn. Invert 4,961.70 It Size: 18 inch L: 122.48It S: 0.91 % Size: 12 inch ' S: 0.90 % J Title: Serrano-Townhomes Project Engineer: Shane Boyle n:\223-01 serrano townhomes\drainage\stonn 1 c.stm North. Star Design, Inc. StormCAD v4.1.1 [4.2014] 06/22/05 07:22:11 AM 0 Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 2 APPENDIX C WATER QUALITY AND EROSION CONTROL CALCULATIONS c North Star Design, Inc. 700 Automation Drive, Unit I Windsor, C080550 RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION: Miramont (Serrano Project) PROJECT NO: 223-01 COMPUTATIONS BY: RB DATE: 9/14/2005 Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria Recommended % Impervious from Urban Storm Drainage Criteria Manual Streets, parking lots (asphalt) Sidewalks (concrete) Roofs Lawns (flat <2%, heavy soil) Runoff % coefficient Impervious C 0.95 100 0.95 96 0.95 90 0.20 0 Basin SUBBASIN DESIGNATION TOTAL AREA (ac.) TOTAL AREA (sq.ft) RUNOFF COEFF. (C) % Impervious REMARKS A At 3.25 141570 0.48 0.33 A2 0.20 8712 0.90 0.93 A3 . 0.28 12196.8 0.90 0.93 A4 0.93 40510.8 0.85 0.86 A5 0.23 10018.8 0.88. 0.90 A6 0.85 37026 0.84 - 0.84 A7 0.20 8712 0.29 0.06 B B7 1.41 61419.6 0.86 0.87 82 0.12 5227.2 0.56 0.44 B3 0.12 5227.2 0.55 0.43 B4 0.27 11761.2 0.49 0.34 B5 0.09 3920.4 0.58 0.47 C c1 0.10 4356 0.65 0.57 OS OS7 0.20 8712 0.41 0.23 OS2 0.39 16988.4 0.39 0.20 OS3 0.11 4791.6 0.26 0.01 OS4 0.11 4791.6 0.30 0.07 ' OS5 0.03 1306.8 0.25 0.00 OS6 0.12- 5227.2 0.31 0.09 OS7 1.00 43560 0.88 0.90 Serrano 2.29 99752.4 0.61 0.S3 Total Development 1 12.30 1 535.788 1 0.65 0.57 Eouations - Calculated C coefficients & % Impervious are area weighted C=E(CiAi)/At Ci = runoff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci n = number of different surfaces to consider At = total area over which C is applicable; the sum of all Ai's 1 WO Miramont Flow Working.zls Cval Ult North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 WQ STAGE -STORAGE VOLUME TABLES Water Quality Only LOCATION: Serrano & Miramont Detention pond PROJECT NO: 223-01 COMPUTATIONS BY: RB SUBMITTED BY: North Star Design, Inc. DATE: 9/ 14/2005 Stated Permanent W' Assumed Permanent W� WQ Surface Required Water Quality = 0.279 ac ft Stated Permanent WS = 4957.63 ft EXISTING POND VOLUME Stage (ft) Surface Area (ftz) Incremental Storage (ac-ft) Total Storage (ac-ft) V cut Time Seconds 4957 27627 0 0 4957.63 32243 0 0 4957.63 32243 0 0 4957.6702 32538 0.030 0.030 1351.91 4957.7105 32833 0.030 0.060 241.16 4957.7507 33128 0.030 0.091 88.30 4957.791 33422 0.031 0.121 43.20 4957.8312 33717 0.031 0.152 25.07 4957.8715 34012 0.031 0.184 16.11 4957.9117 34307 0.032 0.215 11.11 4957.9519 34602 0.032 0.247 8.06 4957.9922 34897 0.032 0.279 6.09 4958 34954 0.006 0.285 4959 42684 0.890 1.175 I otal I Ime = i tui 29.5 Pond Outlet invert = 4957.09 ft Current Ponding in Outlet = 0.54 ft = Plate Base Height Weir Plate Height.= 0.90 ft Bottom of Plate = 4957.09 ft Bottom of notch = 4957.63 ft Notch Height = 0.36 ft min hrs Miramont Detention Pond.xls Display Stage -Storage U i� North Star Design, Inc. 700 Automation Drive, Unit (- Windsor, CO 80550 COMPOSITE REQUIRED WATER QUALITY VOLUME SERRANO AND MIRAMONT LOCATION: SERRANO TOWNHOMES PROJECT NO: 223-01 COMPUTATIONS BY: RB . SUBMITTED BY: North Star Design, Inc. DATE: 9/14/2005 From Urban Strom Drainage Criteria Manual, September 1999 Use: 24 -hour WQ Stage volume drain time for extended detention BASIN Water Quality Capture Volume = WQCV = a ' ( 0.91 ' 13 - 1 A 9 ' I2 + 0.78 ' 1 ) 1� I = Imperviousness Required storage = WQCV / 12 ' tributary drainage area WQ Stage Hour = 24 a= .1 MAJOR Trib. % Imperv. WQCV Req. Storage req. vol DWo BASIN area (in. of runoff) Req. Stor "1.2 (ac) (1) from Fig. EDB-2 (ac-ft) (ac-ft) (ft) Composite 12.30 57 0.227 0.233 0.2792 0.356 CompositeWQCV North Star Design, Inc. 700 Automation Drive, Unit I Windsor, CO 80550 V CUT WEIR DESIGN FOR WATER QUALITY RELEASE SERRANO AND MIRAMONT LOCATION: SERRANO TOWNHOMES $ tan B H� PROJECT NO: 223-01 Q -C wt * Y5 %y2 g COMPUTATIONS BY: RB SUBMITTED BY: North Star Design, Inc. DATE: 9/14/2005 Bottom Angle = 45 degrees Height of Wier Notch= 0.36 ft Top Notch Width = 0.28 ft g = 32.2 fUS2 Number of Notches = 3 Plate Height = 0.90 ft H (ft) 45 degree Cwt values 0.2 0.62 0.4 0.605 0.6 0.596 0.8 0.588 1 0.585 Water Surface Elevation (ft) H Stage (ft) Incremental Storage (fe, Single Notch Flow (cfs) 3 Notch Flow (cfs) Time to Next Stage (min) 4957.992 0.36 _ 1398.44 1.28 3.83 6.1 4957.952 0.32 1386.57 0.96 2.87 8.1 4957.912 0.28 1374.70 0.69 2.06 11.1 4957.871 0.24 1350.97 0.47 1.41 16.1 4957.831 0.20 1350.97 0.30 0.90 25.1 4957.791 0.16 1339.10 0.17 0.52 43.2 4957.751 0.12 1327.24 0.08 0.25 88.3 4957.71 - 0.08 1315.37 0.03 0.09 241.2 4957.67 0.04 1303.50 0.01 0.02 1351.9 4957.63 0.00 0.00 0.00 0.00 0.0 Total = 1791.0 Total Time in Hours= 29.9 Miramont Detention Pond.xls Display V cut o oq cn LO M m CD Nr m 0 M 0) Go uj w w w w 0 0 0 0 0 0 cq3 a�) 0- 0 to =1 C/) II I'd 00 0 as ro 0 0 0 0 0 0 mi to w 0 U cd cd > > ci Lu �> North Star Design 700 Automation Drive, Unit I Windsor, CO 80550 EFFECTIVENESS CALCULATIONS i E PROJECT: SERRANO SUBDIVISION STANDARD FORM B COMPLETED BY: SB DATE: 19-Oct-05 EROSION CONTROL C-FACTOR P-FACTOR METHOD VALUE VALUE COMMENT BARE SOIL 1.00 1.00 SMOOTH CONDITION ROUGHENED GROUND 1.00 0.90 SEDIMENT BASIN 1.00 0.50 ROADS/WALKS 0.01 1.00 GRAVEL FILTERS 1.00 0.80 PLACED AT INLETS SILT FENCE 1.00 0.50 STRAW MULCH 0.06 1.00 ESTABLISHED GRASS 0.08 1.00 STRAW BARRIERS 1.00 0.80 EFF = (l-C*P)* 100 MAJOR SUB BASIN AREA EROSION CONTROL METHODS BASIN BASIN (Ac) 1 0.43 BARE SOIL 0.00 Ac. ROADS/WALKS 0.07 Ac. STRAW MULCH 0.00 Ac. " ROUGHENED GROUND 0.36 Ac. NET C-FACTOR 0.84 NET P-FACTOR 0.29 EFF = (1-C*P)* 100 = 75.8% 2 0.30 BARE SOIL 0.00 Ac. ROADS/WALKS 0.13 Ac. STRAW MULCH 0.00 Ac. ROUGHENED GROUND 0.17 Ac. NET C-FACTOR 0.57 NET P-FACTOR 6.29 EFF = (I-C*P)*100 = 83.6% .3 0.99 BARE SOIL 0.00 Ac. ROADS/WALKS 0.34 M. STRAW MULCH 0.00 Ac. ROUGHENED GROUND .0.65 Ac. NET C-FACTOR . 0.66 NET P-FACTOR 0.36 EFF = (I-C*P)* 100 = 76.2% 4 0.09 BARE SOIL 0.00 Ac. ROADS/WALKS 0.02 Ac. STRAW MULCH 0.00 Ac. ROUGHENED GROUND 0.07 Ac. NET C-FACTOR 0.78 NET P-FACTOR 0.36 EFF = (1-C*P)* 100 = 71.9% 0.33 0.25 0.75 0.06 -. IErosion.xls 1 of 2 North Star Design 700 Automation Drive, Unit I Windsor. CO 80550 PROJECT: SERRANO SUBDIVISION STANDARD FORM B COMPLETED BY: SB DATE: 19-Oct-05 EROSION CONTROL C-FACTOR P-FACTOR METHOD VALUE VALUE COMMENT BARE SOIL 1.00 1.00 SMOOTH CONDITION ROUGHENED GROUND 1.00 0.90 SEDIMENT BASIN 1.00 0.50 ROADS/WALKS 0.01 1.00 GRAVEL FILTERS 1.00 0.80 PLACED AT INLETS SILT FENCE 1.00 0.50 STRAW MULCH 0.06 1.00 ESTABLISHED GRASS 0.08 1.00 STRAW BARRIERS 1.00 ' 0.80 EFF = (1-C*P)*100 MAJOR SUB BASIN AREA EROSION CONTROL METHODS BASIN BASIN (Ac) 5 0.18 BARE SOIL 0.00 Ac. ROADS/WALKS 0.03 Ac. STRAW MULCH 0.00 Ac. ROUGHENED GROUND 0.15 Ac. NET C-FACTOR 0.84 NET 0-FACTOR 0.36 EFF = (1-C*P)* 100 = 69.9% TOTAL AREA = TOTAL EFF = REQUIRED PS = 1.99 ac 76.5% _ (94.0%*29.77 ac. +.. +99.6%*0.40 ac)/1.14 ac 79.5% 0.13 1.52 Erosion.xls 2 of 2 North Star Design 700 Automation Drive, Unit I Windsor, CO 80550 Project: SERRANO SUBDIVISION CONSTRUCTION SEQUENCE Date: April 5, 2005 Indicate with bar line when constructions will occurr and when BMP's will be installed/removed in relation to the construction ohase CONSTRUCTION PHASE (Week/Month) 1 2 3 4 5 6 7 8 9 10 11 12 Grading (Include Offsite) Overlot Detention/WQ Ponds Swales, Drainageways, Streams Ditches o _ Pipeline Installation (Include Offsite) Water •_ ^, :: Sanitary Sewer ' Q, Stormwater_ Concrete Installation (Include Offsite) Area Inlets Curb Inlets Pond Outlet Structures _ Curb and Gutter .� Box Culverts, Bridges Street Installation (Include Offsite) _ Gradiin /Base 9 , Pavememt Miscellaneous (Include Offsite) Drop Structures Other (List) BEST MANAGEMENT PRACTICES Structural Silt Fence Barriers M 6I+ r h a � 3 e ontour Furrows (Ripping/Disking) Li . Sediment Trap/Filter Vehicle Tracking Pads , Flow arners a es, att es, c wN Inlet i er m; 14;an Sand ags are Soil Preparationr� erracmg _rn„ _ 4 Stream Flow Diversion Rip Hap Other is vegetative emporary Seed Planting u c ing ea an Flermanent beedPlanting boa Installation e ings an e s a s Other is Page 1 . North Star Design 700 Automation Drive, Unit I Windsor, CO 80550 EROSION CONTROL COST ESTIMATE Project: SERRANO SUBDIVISION Prepared by: SB ITEM IQUANTITY JUNIT COST/UNIT ITOTAL COST Silt Fence 880 LF $3 $2,640 Straw Bale Barrier 10 EA $150 $1,500 Gravel Inlet Filter 15 EA 150 $2,250 Construction Entrance 1 EA 550 $550 Su total Contingency (50%) Total 6, 40 $10,410 CITY RESEEDING COST Reseed/Mulch. u oa Contingency (50%) Total $2,313 EROSION CONTROL ESCROW AMOUNT $10,410 APPENDIX D EXCERPTS FROM PREVIOUS REPORTS IBM - November 12, 2004 Mr. Basil Hamden City Of Fort Collins Stormwater Utility Department P.O. Box 580 Fort Collins, Co 80522-0580 Re: Lodge at Miramont Stormwater Certification 1 Project No. 0819-004 Dear Basil, The purpose of this letter is to certify the construction of the pond at the Lodge at Miramont. A survey crew recorded final site information on September 22, 2004, from which we calculated the 100-yr storm water surface elevation and the detention volume of the pond. The detention pond was originally designed in the "Overall Drainage Study for Oak/Cottonwood Farm — McClellands Basin" report. The pond was designed for a peak of 5.0 Ac-ft of storage and a water surface elevation of 4962.6. The pond was redesigned with the Lodge at Miramont, for a peak of 6.0. Ac-ft of storage, and a 100-yr storm water surface elevation of 4962.5. The 100-yr water surface elevation, as calculated from the survey information, based on a storage volume of 6.0 Ac-ft is 4962.68, or 0.18 feet higher than shown on the plans for the Lodge at Miramont. The outlet structure, invert elevation 4957.63, was not changed with the design of the project. �l The increase in the 100-yr water surface elevation of 0.18 feet does not cause the stormwafer runoff to exceed the limits of the stormwater easement along the park and Lodge at Miramont site. Based on the inlet control nomograph and the "Overall Drainage Study. for Oak/Cottonwood Farm - McClellands Basin" report, the _ increase changes the discharge rate from the site from 79.1 to 81.6 cfs. As described in the "Final Drainage Report for the Lodge at Miramont", the 42" RCP directly upstream of the site is not designed to the park convey entire runoff from the basin in the 100-yr storm. A portion of the runoff, overtops Boardwalk, and ultimately .flows into the detention pond at the Lodge at Miramont. The increase in ' 100yr water surface elevation does not change the intent of the current design. Please contact me should you have any questions or require further information. I ' Sincerely, TST, INC. CONSULTING ENGINEERS Fraser Walsh FW/tar Enclosures cc: Mike Backlund, Drahota Construction FINAL DRAINAGE REPORT FOR THE LODGE AT MIRAMONT P.U.D. pzj Submitted to: CITY OF FORT COLLINS March 169 2001 s. 17 l_.I value, 1.0 is used in its place. This procedure for computing time of concentration allows for overland flow as well as travel time for runoff collected in streets, gutters, channels, pipes, or ditches. After the peak runoff was calculated, existing and designed drainage facilities were analyzed both according to the prior four reports and the site conditions. 3.2 Drainage -Plan Development Runoff will sheet flow across the building roofs, landscaped common areas, and the streets, then concentrate at the street, concrete pan, curb and gutter, and swales. Primarily, flow will remain on the surface, running- through sidewalk and curb chases, to inlets and into the detention pond. Offsite drainage from Miramont Neighborhood Park will be conveyed onto the site by overland flow, concentrating into swales along the west property line, into inlets and storm sewer on the proposed site. This will discharge into the detention pond. The runoff collected in the detention pond -will continue to be conveyed across Lemay Avenue via three 36" reinforced concrete .pipes as indicated in the Historic Conditions section of this report. The outlet structure for the detention pond will not be modified in_ any way. - Detention pond elevations have been matched in the 100-year event to prevent exceedence of historic flows. Basins were delineated based on proposed grading. The proposed grading is shown on the Final Drainage and Erosion Control Plan that can be found in the back of this report, This .report delineates the site into four basins: A, B,-C and OS. Basins have been further delineated into subbasins: Al, A2, A3, A4, A5, A6, AT B1; B2, B3, B4, B5 and C1. OS1, OS2, OS3, OS4; OS5, and OS6 account for flows coming from Miramont Park. Runoff from the surrounding sites is discharged onto the site by a 42" reinforced concrete pipe (OS9) and a 15" ADS pipe . (OS10).. This discharge is accounted for in this report with Design Points 18 and 17. The offsite subbasin, OS7, flows onto Boardwalk where it is conveyed to an inlet that was previously designed in the report for The Upper Meadow at Miramont First Filing. This inlet will not be modified in any way. Values for OS7 were found by rational method calculation, however, flow at that location is not used for any design calculations. Flows -from OS7 are .included in the SWMM model for sizing of detention volume. Downstream of this inlet in the .swale is Design :Point 14 in this report. Offsite flows for the neiohborina basin 212 to the south enters the site via. OS8 at design point 14. Finally, the 42" RCP carrying OS9 flows was undersized (RBD, .1996). According to the latest master plan (Icon, 1999) 178 cfs should be carried through the RCP. Actually, only 88 cfs physically flows through the pipe in a 100-year event. This flow was determined by HY8 analysis of the culvert (see Appendix D). For purposed of design, the remaining 90 cfs is assumed to enter the channel at the upstream end, over the outlet to the 42" RCP. In reality, this flow enters the channel in a distributed fashion along Boardwalk between the outlet of the pipe and the detention pond. The results of the hydrologic analysis can be found in Tables 1 and 2 with the methodology of calculations shown in Appendix A. 5 w .. ++ur d N N m N m 0 d 0 0 0 O 0 0 0 O b d r e•� 1 = � a,.T ` vt r P �° m N CI N �•t ^ N ry Y -- - O -• n d "'. Pw _.._._; .N _" �•1 O O� O O e•f 0 0 0 0 O O O 0 0 0 O P d h _�� d P Q �•1 P Cl [•f P P P m P P P m h r P P P n P P P P P P P P P m P P P m n r P P b _�•V - lam o-i a kT_ F NO NO -p U= ." -� d o v� vi d o d P o m m m .n •e m o m vi vi v� C7 ` < oG O O O O N O O O -• -� O O O -+ ^ 0 0 0 � y�1 w=] Vl O d m h b b N L °^ P h N b PO -'A N n S of b r m O N 0 ^_ �O ••� N O^ b �l d_ d m h a{ ~� <<<<<< ty � d vl `U r < — N nl Y Yl N th Y Vl b jl •m q -O m m m m m U 000 000 0 0 0 0 t 7 U` '�N � v.� Y :^ ry ry u s= t NO-O-YO ory > o ry n m a tJ _N. L yP r Q Q Q r S�RR�=^� n a =S _ L W- _- �ti_•� mz mmrPP� -�a a 3 F g 8 m r n r r P n a +occo oo oo0 o d Mad =q <<oo -o oo=riC o ZP T3 g _ • 1 Vl Q U n 0 H H d f 0 y H O O _,amnammm�°-mci Ho o 0 0 0 m> n n m O m � < U q: 14 t�z Q O -3 C 0 19 i I ENVIRONMENTAL PROTECTION AGENCY - STORM WATER. MANAGEMENT MODEL - VERSION PC.1 DEVELOPED BY METCALF ♦ EDDY, INC. UNIVERSITY OF FLORIDA WATER RESOURCES ENGINEEERS, INC. (SEPTEMBER 1970)- �°c-y9-4ckF`` ex,s�:�� COHUIa UPDATED BY UNIVERSITY OF eLORIDA (JUNE 1973) HYDROLOGIC ENGINEERING CENTER, CORPS OF ENGINEERS MISSOURI RIVER DIVISION, CORPS OF ENGINEERS (SEPTEMBER. 19741 BOYLE ENGINEERING CORPORATION (MARCH 1985, JULY 1965) Modified to run M!IOSWMM input files with comment statements and up to 999 elements, 200 diversions up to 50 pairs of hydrographs, storage routing or diversion data September 2000 by Ayres Associates OTAPE OR DISK ASSIGNMENTS JIN(1) JIN(2) JIN(3) JIN(4) JIN(5) JIN(6) JIN(7) 71N(S) JIN(91 JIN (1O) 2 1 0 0 0 0 0 O 0 0 JOUJOU2 JOUT(3) JOUT (4) JOUT (5) 1 JCNT(6) JOUT(7) JOUT(6) JOUT(9)' JOUT(10) 1 2 0 0 0 0 0 NSCRAT(1) NSCRAT(2) NSCRAT(3) NSCRAT(4) NSCRAT(5) 3 4 0 0 0 �1 WATERSHED PROGRAM. CALLED ENTRY MADE TO RUNOFF MODEL •, MCCLELLANDS BASIN MODEL (FULLY INTEGRATED) EXISTING• CONDITIONS JUNE 26, 2000 ADITED 100-YEAR EVENT FILE: 1,111,2-100.DAT THE SEAR -BROWN GROUP. ONUMBER OF TIME STEPS 600 OINTEGRATION TIME INTERVAL (MINUTES) 1.00 1.0 PERCENT OF IMPERVIOUS AREA HAS ZERO DETENTION DEPTH �O FOR 25 RAINFALL STEPS, THE TIME INTERVAL IS 5.00 MINUTES OFOR RAINGAGE NUMBER 1 RAINFALL HISTORY IN INCHES PER HOUR 1.00 1.14 1.33 2.23 2.84 5.49 A.95 4.12 <2.48 1.22 1.06 1.00 0.95 0.91 0.87 0.84 0.81 0.78 0.73 0.71 0.69 0.67 0.00 1 McCLELLANDS BASIN MODEL (FULLY INTEGRATED) EXISTING (IONDITIONS JUNE 26, 2000 Ad)PTED 100-YEAR EVENT FILE: MHC2-100.DAT THE SEAR-BR!,WN GROUp. SUBAREA GUTTER WIDTH AREA PERCENT SLOPE RESISTANCE FACTOR SURFACE STOPAGE(IN) NUMBER OR MANHOLE (FT) (AC) IMPERV. (FT/FT) IMPERV. PERV. IMPERV. PERV. -2 0 0. 0.0 0.0 0.0300 0.016 0.250 0.100 0.300 1 . 4.6 0.75 INFILTRATION RATE(IN/HR) GAGE MAXIMUM MINIMUM DECAY.RATE . NO 0.51 0.50 0.00180 U 80 50 7109. 06.2 40.0 0.0100 0.016 0.250 0.100� 0.300 0.51 0.50 0.00180 60 50 1150. 8.9 -40.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 70 6 10239. 29.4 40.0 0.0100 0.016 0.250 0.100 - 0.300 0.51 0.50 0.00180 130 51 7161. 24.7 40.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 100 51 2875. 13.2 40.0 0.0100 0.016 0.250 0.100 0.300 0.51 -,0. 50 0.00180 150 4 1590. 1.8 80.0 0.0200 0.016 0.250 0.i00 - 0.300 0.51 0.50 0.00180 !10 11 1250. 1.9 99.0 0.0200 0.0I6 _ 0.250 0.100 0.300 0.51 -0.50 0.00180 111 11 700. 1.0 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 112 112 750. 1.3 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 113 12 1200. 1.3 99.0 0.0100 0.016 0.250 0.300 0.300 0.51 0.50 0.00180 114 12 950. 1.7 99.0 0.0100 0.016 0.250 0.100 0,300 0.51 0.50 0.06180 I15 13 1050. 1.7 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 116 13 1400. 2.2 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 117 51 1000. 2.8 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 118 - 14 1250. 1.1 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00.180 320 11 3C5. 2.1 10.0 0.0100 0.016 0.250 0.300 0.300 0.51 0.50 0.001B0 120 22 3875. 17.8 80.0 .0.0200 0.016. 0.250 0.100 0.300 0.51 0.50 0.00180 90 2 5715. 13.1 10.0 0.0100 - 0.01.6 0.250 0.100 0.300 0.51 0.50 0.00190 190 S. 250. 1.4 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 200 20 4550. 31.3 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 210 44 1090. 7.5 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 240 7 1742. 5.0 80.0 0.0100 0.016 0.250 0. 100 0.300 0.51 0.50 0.00180 220 45 3228. 22.2 10.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 260 46 3454. 23.8 50.0 0.0100 0.0116 0.250 0.100 0.300 0.51 0.50 0.00160 230 47 2134. 14.7 10.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 290 291 1278.- 5.9 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 -0.50 0.00180 340 34 1260. 4.3 80.0. 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 280 275 1000. 2.0 99.0 0.0200 _ 0.016 0.250 - 0.100 0.300 0.51 0.50 0.00180 281 28 1650. 3.2 99.0 0.0100 0.016 0.250 0.100 6.300 0.51 0.50 0.00180 282 29 850. 1.5 99.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 _283 .DO 30 1250. 2.0 99.0 0.0100 0.016 0.250 0.I oo- '- 6.:300. 0.51 0.50 0.00180 -160 33 700. 5.6 BOA 0.0300 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 16 3500. 4.0 84.0 0.0200 0.016 0.250 0.100 0.300 0.51 0.50 0.001BO 121 16 850. 1.4 80.0 ' O.Oi00 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 122 22 1200. 1.8 80.0 0.0100 0.016 0.250 0.100 . 0.300 0.51 0. 50 0.00180 250 250 500. 1.6 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 270 270 625. 3.3 60.0 0.0100 0.016 0.250 0.100 0.300 0.51 0. 50' 0.00180 271 271 2017. 6.3 55.0 0.0100 O. Olt; 0.250 0.100 0.300 0.51 0.50 0.001B0 171 272 8i7. i.5 31.0 0.0900 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 360 36 3223. 2.4 87.0 0.0200 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 ' '201 _ 320 3213. 14.8 25.0 0.0183 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 202 322 1873. 21:5 50.0 0.0165 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 203 172 7024. 32.3 80.0 0.0100 0.0It; 0.250 0.100 0.300 0.51 0.50 0.00180 204 166 4138. 19.0 80.0 0.0100 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 205 168 650. 5.8 47.0 . 0.0105 O. OIG 0.250 0. 1C0 0.300 0.51 0.50 0.00180 206 ill 95E. 7.7 70.0 0.0080 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 207. 176 1718. 13.8 57.0 0.0235 0.016 0.250 0.100 0.300- 0.51 0.50 0.00180 208 178 2936. -33.6 70.0 0.0170 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 209 321 6795. 23.4 40.0 0.0085 0.016 '0.250 0.100 0.300 0.51 0.50 0.00180 165 324 299'.. 10.3 .40.0 O.Oi00 0.016 0.250 0.100 0.300, 0.51, .0.50 0.00180 211•�- 325 3165. 10.9 64.0 0.0200 0.016 - 0.250 0.100 0.30C 0.51 0.50 0.00180 _2,12 328 1220. �.5 1 179 465. 1.6 90.0 0.0110 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 331 SOC. 0.7 90.0 0.0270 0.016 0.250 0.100 0.300 0.51 0.50 0.00160 327 1405. 1.0 90.0' 0.0060 .0.016 0.250 0.100 0.300 0.51 0.50 0.60180 301 3315. 28.5 -71.0 - 0.0050 0.016 0.4.30 0.100 0.600 0.51 0.50 0.00180 95 13736. 47.5 45.0 0.0100 0.016 0.390 0.100 0.600 - 0.51 0.50 0.00180 369 6839. 78.5 - 3.9 0.0110 0. 016 0.250 0.100 0.300 0.51 0.50 0.00190 372 2535. S.7 31.2 O.OZ00 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 360 295". 5.4 17.0 0.1262 0.016 0.250 0.100 0..300 0.51 0.50 O.CQ180 370 2042. 7.0 40.0' 0.0200 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 362 BEE. 1.6 4.0 0.1262 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 371 80%. 2.8 40.0 - 0.0200 0.016 0.250 0.100 0..300 0.51 0.50 0.00180 363 Se 9. 2.1 2.3 0.1282 0. Olt; 0.250 0. 100 0..300 0.51 -0. 50 0.00180 367 495. 0.9 1.0 0.0500 0.016 0.150 0.100 0. 300 0.51 0.50 0.00190 40 26470. 91.2 34.0 0.0200 0.016 0.250 0.100 0. 300 0.51 0.50 0.00180 374 4179. 14.4. 40.0 0.0200 0. 016 0.250 0.100 0.300 0.51 0.50 .0.00180 39 1924. 67.0 5.0 0.0170 0.016 0.250 0.100 0.300. 0.51 0�.50 0.00180 599 1507, 17.357.0 0.0190 0.016 0.250 . 0.100 0.300 0.51 0'.50 0.00180 593 1699. 19.5 47.0 0.0150 0.016 0.250 0.100 0.300 _ 0.51 0.50 0.001B0 36B 4057, 6.5 5.0 0.0200 0.OIG O.Z50 0.100 0.300 0.51 0.50 0.00180 611 4751. 16.4 45.0 .0.0060 0.016 0.250 0.100 0.300 -0.51 0.50 0.00180 621 2936. 10.1 45.0 0.0120 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 631 10733. 24.ti 55.0 6.0100 0.016 0.150 0.100 0.300 0.51 0-. 50 0.00180 102 4,4. 0.1 75.0 0.0200 0.016 0.150 0.100 0,300 0.51 0.50 0.00180 651 6329. - 20.3 45.0 0.0090 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 368 137. 9.0 5.0 0.0090 0.016' 0.250 0.100' 0.300 0.51 0.50 0.00180 671 17484. 52.3 57.0. 0.0090 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 681 7635. 31.5 52.0 0.0080 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 102 437. 5.0 20.0 0.0080. 0.016 0.250 0.100 0.300 0.51 0.50 0.00180 'i . .i 7z �'^�1\t: y �F��'��;��.dt\}ier•..�,--�.��-.v...sct>aw4..wuw..�...,..........,...................................,..,,,�,a.,.�,ar��,,,,,- . M i FINAL DRAINAGE AND EROSION CONTROL STUDY _ FOR THE 1 AMLET AT MIRAMONT P.U.D. FORT COLLINS, COLORADO March 29, 1996 Prepared for. KEM Homes P.O. Box 1845 3000 South College Avenue Fort Collins, CO 80526 Prepared by: RBD, Inc. Engineering Consultants 209-South Meldrum Fort Collins, Colorado 80521 (970) 482-5922 RBD Job No. 567-006 „ CUEHT /�/r2D�GK �NERG JOB NO.—`-Gy'a%/ . Nc PROJECT i Z_Ml �OOO CALCULATIONS FOR .SW (hI'yl rY}GEC Engineering Consultants MADE BY • % DATE CHECKED BY -'DATE SKEET_3A OF $WMMI ScIg6,14,Mc ;:<RMONY �20F0 4QZP I --7 ---------- ---- MIPLAMolfr WLDWOOD FARMS --I-------------- MCCLELLANDS ASN U.OMLAWB S UM U"M FLAK BY GXV#fOW OVAN6 W— DAM AVC I"L 311 14 !R CREW um it ffm PDA& A Ulm PIM.01 " m W� omma Im IN" E*m I - No" 1 I 1 Y N a V O C V 7 _ V C v fJ U u to ca cc - I-- coo st to N N T Cof O 0 N. QQ w W u c" �aF•. Z. U O > Q vo C* a�N V ~Om—a,W c F• oZZ U a y ai Z F- F- 0E- 0 a U. a0 co co 0 co tN to O W o 0 0 0 o c o Q 0 M o \ o o o o o CDOOf Cl) Ot <O � � Z 0 0 r M to M c') r YV N O M N ui . a 10 r O) Qt o O v c'i N Ln tri M r ui O to o r- v, r t0 r � co co r m N r 0 c'7 co co co co " V O O o O O o O N N W N o 0 0 0 0 0 o Q O O O O O O O O O O O O CDrn coo v o m 0 0 W a E r t0 N O M r N r a r . N N N N N N "Nil Y Y. cl LL 00 4 V 3 32 d .+ N a7 N 3 d E C c o a�i `m cco m o m� oloE (on=m m = 0) o C14 o 9 =cam cc 0)o COCIO o N L eN— _ d '0 to M RB-D, Inc., Engineering Consultants Detention Pond 180 (340) 1 Capacily-Discharge Rating Curve Pond Inlet Outlet Total Elevation Storage Control Control Outflow (ft) (AF) HW/D (cfs) (cfs) (cfs) (1) .(2) (3) (4) 4957.5 0.00 0.00 uo- 0.60 uo 4958.0 0.44- 0.24 4.00 6.43 4.00 4958.5 0.99 0.49 9.60. 15.90 9.60 4959.0 1.55 0.74 ' 18.00 25.32 18.00 4959.5 2.28 0.99 28.40 32.39 28.40 4960.0 3.01 1.24 37.20 38.20 37.20 4960.5 3.85 .1.49 45.60 45.94 45.60 4961.0 4-6.9- .1.74 52.40 53.37 52.40 Pond Outlet Invert = 4957.52 ft IVISL Box Culvert Height = 2 ft Box Culvert Width = 4 ft.- Notes: (i) HW/D = (WSEL - invert el.) / Box height (2)From FHWA nomograph (following) . (3) Derived from UDSEWER analysis (see following page) (4) Minimum of inlet control or outlet control discharge. 567-006 47.5 cfs @ WSEL 4960.64 03-Apr-96 �RBD, Inc., Engineering Consultants Detention Pond 180 (340) 567-006 . Area CaoaCW Rating Curve Cumulative Elev Area Area Storage (ft) O (ac) (ac-ft) V = d/3'(A+B+(AB)^0.5) 4.2.5 1:53.0 4954.0 1-2�7--,197811 ea 4955.0 4956.0 4957.0 4957.5 34,696 0.80 0.00 4958.0 41,414 0.95 0.44 4959.0 55,791 1.28 - 1.55 4960.0 72,237 1.66 3.01 ft at WSEL = 4960.65 4.1 ac- 4961.0 74,14-6 1.70. 4'.'69"' Detention Pond 340 567-006 Outlet Rating Curve (from UDSEWER) Q(pond) Q(Lemay) Q(out). Start. D/S U/S CE 340/180 CE312/177 HWL HWL (cfs) (cfs) (cfs) (ft el) (ft el) (1) 0) (2) (3) (4) - 0.00 - ----------- 0.00 0.00 4957.10 4957.52 0.36 2.48 2.84 4957.28 4957.65 2.87 6.90 9.77 4957.49 4957.78 9.18 14.26 23.44 4957.74 4958.17 23.63•• 25.39 49.02 4958.09 4958.88 34.08 _ 40.67 74.75 4958.35 4959.62 39.50 48.62 88.12 4958.47 4960.12 . Qi (Pm� _ LI cls 45.64 52.26 97.90 4958.55 4960.48 a 55.00 57.81 112.81 4958.67 4961.11 (5 i0" 60.00 60.77 120.77 4958.73 •-;. 4961.46 (5) Notes: -(1) Hydrographs from SWMM model (2) Sum of conveyance element hydrographs (3) From D/S channel rating (following) (4) Determined by numerous iterations of UDSEWER model using the above conveyance element hydrographs (5) Discharges estimated for upper boundary of rating curve r � l � 1 '_ter f1_' • � ^•a. .. N ). _•✓ i � —L, � i ;-- y :� Ire z'� Ir t ! I _ Z •C - Ii i :tvi T,. le.' a42 It. t i Ijf _ �• { `•- yy/t , r t i ..ter: - a. ..,r .._., r" �� � 1, •--� to JO 04 in rl co -C-4 : ' _ . -: f -i f �i' i -•":' i'/'. ' n L• CO eq m -•1',. '�.�.:.r •1 is ' At - IC 04 i. L j` E a : DRAINAGE C�2IITERIA MANUAL (V. 1) TABLE RO-3 Recommended Percentage Imperviousness Values - Land Use or Surface Characteristics Percentage Im erviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: Sin le-famil Multi -unit detached 60 Multi -unit. attached 75 Half -acre lot or larger ' Apartments artments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools .50 Railroad yard areas 15 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 0 Lawns, clayey soil 0 See Figures RO-3 through RO-5 for percentage imperviousness. Based in part on the data collected by the District since 1969, an empirical relationship between C and ' the percentage imperviousness for various storm return periods was developed. Thus, values for C can be determined using the following equations (Urbonas, Guo and Tucker 1990). CA = KA + (1.31i'—1.44i' + 1.135i — 0.12) for CA >— 0, otherwise Q4 = 0 (RO-6) ' Cco = Kco + (0.858i' — 0.786i2 +.0.774i + 0.04) (RO-7) CB = (CA + Ccn )/2 in which: i = % imperviousness/100 expressed as a decimal (see Table RO-3) 0612001 RO-9 Urban Drainage and Flood Control District ' Table 3-3 r. ' 7t74T=CML MMM leD@7OF8' COmpy= = Fm c0187mTE ]NIp =zS Character surface ' 4f Rmofff coefficient Streets, Parking Lots, Drives: Asphalt Concrete..................................... 0.95 ........0.95 Gravel... ' ....................... •..... 0.50 Roofs ........................................... 0.95 lawns, Sandy Soil: ' Flat <28.:................................... Average 2 to 7%., 0.10 Steep >7%0.15 ...................... .... 0.20 Lawns, Heavy Soil: Flat <2&.. .. .............. 0.20 Average2 to 7% .............................. 0.25 Steep>7% ............. ...... . 0.35 3.1.7 Time Concentration of In order to use the Rainfall intensity Duration Curve, the time of concentration must be ]mown. The time of concentration, T,, represents the time for water to flow from the most remote'part'of the drainage .basin under consideration to the design point under consideration. The time ' of concentration can be represented by the following equation. Te = to 't tm " Where: ' Te = Time of Concentration, minutes t,, = overland flow time, minutes tL= travel :time, .in, the .gutter, .swale, or.storm;sewer, Xinutes The overland, flow time, tw,.,can be determined either by the following equation or the "Overland Time of Flow Curves- from the Urban Storm Drainage Criteria Manual,. included in this report (See Figure 3-2). 187(m-CCf)B112 - Tav— SU3 . ` Where: Te, = Overland Flow Time of Concentration, minutes S = Slope, $ C = Rational Method Runoff Coefficient ' D = Length of Overland Flow, feet- (5009 .*__i.nm) = Frequency Adjustment Factor ' The travel time, t" in the gutter, Swale, or storm sewer can be estimated with the help of Figure 3-3. 3.1.8 Adjustment for lnfregmmt Storrs ' The preceding variables are based on the initial storm, that is,the two to ten year storms. For stows with higher intensities an adjustment of the runoff coefficient_ is ' required because of the lessening, amount of infiltration, depression retention, and other losses that have a propoitionaliy smaller effect on stow runoff: These frequency adjustment factors are found in Table 3-4. May sed Revised January 1997 Design Criteria • ' 3-5 City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (5 minutes - 30 minutes) Figure 3-1a Duration (minutes) 2-year Intensity in/hr 10-year Intensity in/hr 100-year Intensity in/hr 5.00 2.85 - 4.87 9.95 6.00 2.67 4.56 9.31 7.00 2.52 4.31 8.80 8.00 2.40 4.10 8.38 9.00 2.30 3.93 303' 10.00 2.21 3.78 7.72 11.00 2.13 3.63 7.42 12.00 2.05- - 3.50 7.16 13.00 1.98 . 3.39 6.92 14.00 1.92 3.29 .6.7-1-- 15.00 1.87 3.19 6.52 - 16.00 1.81 - 3.08 6.30 17.00 1.75 2.99 6.10 18.00 - 1.70 2.90 5.92 19.00 1.65 2.82. - 5.75 20.00 1.61 2.74 5.60 21.00 1.56 2.67 5.46 22.00 1.53 2.61 5.32 23.00 1.49 2.55 5.20 24.00 - 1.46 2.49 5.09 25.00 1.43 2.44 4.98 26.00 1.40 2.39 4.87 27.00 1.37 2.34 4.78 28.00 1.34 2.29 4.69 29.00 1.32 2.25 4.60 30.00 1.30 2.21 4.52 No Text Q %pE}IM91Nt _ I� 11 MLT \�J WAIDW/lllE & A - T11E Pl[T R WILIET _ i I l / , OIUf1I10E . 1:1305 J CONTROL LEOENO 'Zwl p DE,M POINT =� l 60 Q D YR RVNtlE CCCri1CKNr 'C m WvBiIT 0 RAS We�ucy AREA N ALPES Q m - .w- __ _ FLOW DIRECTION U ; $�Q (9I¢p BEEMENEREME BASIN GOFi ryC tVOrOI� EvsnNG PIPES �V 0% Q�'y One 5 - -- - � - -� - -� - PRbOSED STO PIPE 0.18.5% `eel w gg o _ - yWe_____ E[SnRG J'CWTWR 'Why,'0 It, O.Lu Q2 20 10 / 0 20 90 - E[5TMG 1 LM1WR \, -e9]5� PRLeDJEO 5 CWiWP IF^^//aA e. /g�� _ -_ PRGCSED 'CdRWR 1 V \- _ _ll SCAIE: 1 20' mall I s str rzxa - 1: LO1s1PVCMPI ENAAx(E Q N� o weer PxorzeTlDx m STANDARD EROSp1 AND SEDIMENT CONTROL COIISTRUCTIM MAN NOTES 90.xapea. ]DN 1. 1M croak, <mhd oW,,,t,, wort sm Mbmi at Rest t myl far (24) own well to i 4970-. m, emalmrNm an the nee. ebp / 2 Hire a 1, N I WFWJI the IT imagination an the acrylp w / / \ J. M MIthrel be iii at the aine _Pliffififirter I" ado appi m a wool, < WMclo a$ me � 9 (Stockpiled, n 9 M 9. ). IA rp < Ird F the Wallace project M ont d<atM j 61 4. At al teners couning confirwi the Tenenbaum Mail I be useful Fee preventing are 4 ZO 9 9 property k 1 wi , / // mFYM T pal pOldsmobile he noel n9 oAndO / jr( nessibusing 2 } Pn d vp Ntl W protected old odefirefil InforlyhorKornai in Of ^i - c t� t W the W,,bmt p°hill I tend tee / Irvc 'Atte, A once °Ill tom m ay be t° the M o) rry M O O m l I L. AN " D 9 ond dulturning lCtIlAy ( m If / Md°de°<m ) Wool As beat I, a w wee W9 confirce IIct O If B�cted 1 Ad "mci nrrytect street � do Lace.. by tend Ofil o y or parromont eyounfin _49734tl dl. ImA<agn9 etc) Is nctmM unless otherwise Wa ptoce by Ad 4y �- IXf/WnIT O i I 1 ,. N9� V to enormous, � autocrat. OF 0orwr (eWlonce) wu t re O w o L11 I O to O 0 `; Bece t (n buyer to lmre Inc <mtwp Fat pmn _ old `m1 _ I the surrouldho a tart ,an, me mrorle,ty g uB " maurn"ed by the erosion Country! wool d merwourall after the site axe nmm.d n<t Y ,t..an aamm nn th e e .now, Formally oloon, _ III 1 Ae 'm fmu to i of d eeawmt and derv, from d ono o9my4onucbr. 973-- j Id` mlyd we. n e rn and 9 Toe mdnlau < Lrw. nnA ON 0.67 om NOR tot0 _.O.43 .58 I CIO 2 we Zyet 1 JS .pre. 0 c ---- - c _ _ _. _ _ _--Nao- 3 _._ o - - Ofin ®® OIL L A+ l a%1 OF rJ n t DRAINAGE SUMMARY TABLE BASH DESIG. AREA ACRES CIO VIM TOO " To100 Boo 010 Cie 0100 CMS I a." 0.58 0J2 7.9 6.8 1.0 28 2 0.60 0.M 0.69 QS 7.5 1.5 D3 D 0.99 D67 0.84 &0 5.0 5.2 BS A 0.09 0.T0 0.87 5.0 5.0 0.3 0-0 5 0.18 0.57 OJ1 5.0 5.0 0.5 1J COPOSM 229 0.61 0Jl 9.7 8.6 5.4 1AA One �__. ..- , I /\ �filed �_ 7 CALL UTRITY NOTE1CAlICN E� ERLL NOTES oCENTER /O�F/CCOOLORAA/D�Oe% 1. SEE LANDSCAPE PLAN FOR PLANTINGS THROUGHOUT THE SSE. 1100IA922=1Ov• 2. NO IMPROVEMENTS TO BOARDWA DRIVE M SOLTi LEMAY KFFO OND yW GRADE as EXCAVATE ADVANCE AMENUE ARE PROPOSED, FOR THE mwa rc tlx9wmWlo O, THIS PROJECT INCLUDES MWIFICATON OF THE E)STINC OIITIET DI9ER u1u1Es. STRUCTURE LOCATED IN THE MIRAM(YIT DETENTION PAID IN ORDER TO PROVIDE E%TENDED WATER WAEITV DETENTON FOR THIS SITE AND THE MIRAMONT OENELOPMENT. REFER TO SHEET 8 FOR A DETAIL ( THE OLTET STRUCWRE MOOIFICATON. / de w m °a. f elfin al m. nMol Or Other dN pypte of war me Wye our* ,4 h ale eaewdn m ' d a .o.NWn9 day '° ' Willyt _ _ _ p 110 An retained "Molloyo,oa, a`e olio pn 01Aa°mr ll ee,bae&. nd x..nwn a aWdee of n r letMeadow wor tool, ..Iwo non my school i of tly U State, I y 11. MNo am chip, end Folio ton (10) fox n helix. N w "Pies " be pen 1n fill, Ae wt trainable by .face'WOMxe. woof and par 011ndn9 .m aE y sell a Fgan mulm °tmo ,m9 after et, 00) c"*md" and n. Qr The elmmwmm wmn 1< lty of aetnt mm of x "fill" mWond .term whm w \ , 0 upon aaaae me pojcbeforebefFallinthe t a wee toe Ell Wmn 1 _ / - 1 they (Myyro l derHmenmw° Aurce m (HOA). z • (rr 97e- 1 1 u. cry won Fan and Cdaraaon onmoaa P. S1etm (mPs) requirement mows N 0 php mw t 9= de yoner show I I cd,emet t' throw "Willi. ts ande but r po M! to ne adei a,ne%m bm� III _ t i5 aaaaawf .inn 1 wmr 1, `w+ >_ z fi e4t me dppaeal of 1 m the . do Maycnl a «a oat ma fedwa re9° 1. o «� em<. wlln°a°ny,nne O J 1- 1 A A deel9rGtn mp x N W,A ee concrete wy xvte iti Ene mw Co 0- aide pe rnM tee or Web bill without molawriffis °M IxeW at eel rtry (JD) feet 1 , M1sn m, .dlwwa, ✓1^9 c°n.4uc11m Bp°n axWxtlm Of caneWetbl xtMt" the D LL comeWee11M.MwY r ee remmmd me preP.r1, elq°..d Of p a w mw ben V/ AT 1 1 1a ice onve Heat anent cue n1 mwe off a1 4fiest lots men mm of Me z .. \ fnaedp eea'nwlt/wu wen We "I be Neltllu and awxidnM onta H, blow we O LWly esions Y)eWMN byfeet by 1x eventual Ki eW door (fillL,. oty Z A Wae t to Ba .d°'°d1.WAwrte AWLLQ� y w. o. Other 9 1&neIf ..e.a. M 1 n Cori or the W nody em4a m M a wed to elect I. LW t m tFeee 1n Der hop mmt ,lull mwwee en dxwm4&e nxaea 1 �I' Sep as Ali by the cly/<mn1y.'� V/ i Coy of Fat Collins, Colorodo UNLITY PLAN APPROVAL APPROVED City En9ener Date CHECKED BY: SHEET states A Wtlaxw vDity Date CHECKED BY. Q stormwaln unNy, Cab v CHECKED BY. PVLa k lNommi Date CHECKED BY 8 OF 10 Frol ugnex Pot& CHECKED BY: Date Job No 223-01