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HomeMy WebLinkAboutDrainage Reports - 03/12/2004in "I w dt GE AND:. ONTROVREPORT -',;,- SHO �TRACFB','� lY. Repolt Io I LJ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FINAL DRAINAGE AND EROSION CONTROL REPORT SHOPKO P.U.D. TRACT B I 1 1 1 1 1 1 FINAL DRAINAGE AND EROSION CONTROL REPORT SHOPKO P.U.D., TRACT B Prepared for: Doberstein Lemburg Dan Bernth 702 W. Drake Rd, Building E, Suite B-102 Fort Collins, CO 80525 Prepared by: North Star Design, Inc. 700 Automation Drive, Unit I Windsor, Colorado 80550 Ph# (970) 686-6939 Fax# (970) 686-1188 February 17, 2004 Job Number I70-03 1 % North Star design, inc. February 17, 2004 ' Basil Hamdan City of Fort Collins Stormwater ' 700 Wood Street Fort Collins, CO 80522-0580 ' RE: Final Drainage Report for ShopKo P.U.D., Tract `B". Dear Basil, ' I am pleased to submit for your review and approval, this Final Drainage & Erosion Control Report for ShopKo P.U.D., Tract `B". I certify that this report for the drainage design of ShopKo P.U.D., Tract `B" 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. 1 1 1 ii ' 700 Automation Drive, Unit I Windsor, Colorado 80550 970-686-6939 Phone . 970-686-1 1 138 Fax I ' TABLE OF CONTENTS TABLE OF CONTENTS.............................................................................................................................iu 1. GENERAL LOCATION AND DESCRIPTION ' 1.1 Location...............................................................................................................................I 1.2 Description of Property........................................................................................................ I 2. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description...................................................................................................... 1 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..............................................................................................................3 3.4 Hydraulic Criteria................................................................................................................4 4. DRAINAGE FACILITY DESIGN 4.1 General Concept..................................................................................................................4 ' 4.2 Specific Flow Routing ............................... '.......................................................................... 4 4.3 Drainage Summary ..............................................................................................................5 4.4 Variance Requests...............................................................................................................6 5. EROSION CONTROL 5.1 General Concept..................................................................................................................6 5.2 Specific Details....................................................................................................................6 ' 5.3 Dust Abatement...................................................................................................................6 5.4 Tracking Mud......................................................................................................................7 5.5 Maintenance........................................................................................................................7 ' 6. CONCLUSIONS 6.1 Compliance with Standards................................................................................................7 6.2 Drainage Concept................................................................................................................7 6.3 Water Quality and Erosion Control Concept....................................................................... 8 7. REFERENCES.................................................................................................................................8 ' APPENDICES A Vicinity Map B Hydrologic & Hydraulic Calculations C Detention and Water Quality Calculations D Erosion Control Calculations E Figures and Tables F Excerpts from Previous Reports 1 ' 2. I GENERAL LOCATION AND DESCRIPTION 1.1 Location This site is located in ShopKo P.U.D., Tract `B" Situated in the Northwest Quarter of Section 36, Township 7 North, Range 69 West of the Sixth Principal Meridian, in the City of Fort Collins, County of Latimer, State of Colorado. See the vicinity map in Appendix A. The project is located north of Boardwalk Drive and west of JFK Parkway. The site is bounded to the north by existing commercial development (ShopKo retail store), to the east and south by existing JFK Parkway and Boardwalk Drive and an existing parking access road to the west. 1.2 Description of Property The entire project consists of approximately 1.76 acres of undeveloped land. This site has existing curb and gutter along the eastern, western and southern boundaries. A 4.0' high stockpile of dirt exists in the center of this site. Existing onsite flows are routed to an existing inlet located in a sump the southeast comer. The site slopes from the north to the southeast at slopes ranging from 0.5% to 4.0%. The proposed development consists of two buildings that will be used as office space, retail and possible auto related uses. The site will gain access from existing drives on JFK Parkway and Boardwalk Drive and from the existing ShopKo Parking lot. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The proposed development lies within the McClellands Mail Creek Drainage Basin and Fossil Creek Drainage Basin. The site is included in the area covered by the Final Drainage Report for ShopKo P. U.D. Portions of this report are included in Appendix E. According to the above -mentioned report, allowable release from this site is equal to (21.44 cfs) the I00yr storm event for the old rainfall criteria. However since new rainfall criteria (1DF curves) have been adopted, it is required to detain for the difference between the two rainfalls. Water quality is also required with the development of this site. The d I ' area contributing to the water quality pond is approximately 2.33 acres. The additional ' area (0.60 acres) being treated for water quality is from the south wall of ShopKo Retail store to the north property line of this site. There is an existing detention pond located in the northeast corner of ShopKo P.U.D. that is labeled as East Pond in Final Drainage Report for ShopKo P. U.D. Runoff from this proposed development will be conveyed to the existing storm system and to the East Pond. Runoff from the East Pond is discharged ' into the No. 2 Canal northeast of the site. In the event that the required water quality / detention pond should overtop runoff will be conveyed to Fossil Creek in the Fossil Creek Drainage Basin. Due to existing landscaping that is required to be saved, the southern portion of the site is unable to be graded so runoff is conveyed to the proposed detention pond. It is proposed to allow this undetained flow to enter Boardwalk Drive and flow west on Boardwalk Drive to College Avenue. This undetained runoff flows from landscape areas and therefore runoff has maintained good water quality. Runoff from this undetained basin ' will be conveyed to Fossil Creek. This undetained runoff is deducted from the allowable release rate. 2.2 Sub -basin Description Sub -basins are described thoroughly in Section 4.2. 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), June 2001, developed by the Denver Regional Council of Governments, has been used. 1 3.2 Development Criteria Reference and Constraints Runoff from this site and the allowable release rate has been routed to conform to existing drainage reports completed that have included this area, including the Final Drainage Report for ShopKo P. U.D., Dated May 11, 1993 by TST Inc. Project Number 10-724-000. 2 The streets and associated drainage systems surrounding the site are existing. There is a storm system existing in the east portion of the site. Runoff from this site has been accounted for in the design of the existing storm sewer system designed with ShopKo P.U.D. However with the rainfall criteria adopted in March 1998 detention and water quality will need to be provided due to City of Fort Collins requirements. ' Onsite detention is proposed for this site to account for this new rainfall criteria for the City of Fort Collins Area. Release for this site will not exceed the approved 21.44 cfs ' (100yr release rate for the old rainfall data). Runoff flows will enter the existing storm sewer system and will be detained in the East Detention Pond as described in Final Drainage Report for ShopKo P. U.D. It has been found that the existing storm sewer will not convey the allowable release rate to the existing pond with the proposed storm sewer layout. Therefore it is proposed to reduce the release rate from the detention outlet structure to a point where the 100yr HGL is slightly below the flowline elevation in the existing inlet located in JFK Parkway. Allowable release from this site is 21.44 cfs. minus undetained flows, (basins 2 & 6) ' which equals 18.0 cfs. This minimum release rate causes surcharging on the existing inlet located on JFK Parkway, therefore to avoid flooding a proposed release rate from the detention pond is limited to 17.25 cfs. Water quality is also provided in the form of extended detention. Water quality ' calculations are included in Appendix C. 3.3 . 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. I 3 I 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 also included in Appendix B of this report. 4. DRAINAGE FACILITY DESIGN ' 4.1 General Concept Runoff from this site will flow south in the parking lot via sheet flow and curb & gutter to the proposed storm system. This system will convey runoff to the detention pond. The existing storm sewer system has been modeled using Haestad Methods StormCad v4.1.1. ' Basin 2 is not routed through the detention pond. The amount of runoff from basin 2 was deducted from the allowable release rate for the design of the detention pond. Runoff generated by basin 2 is detained in the East Pond as described in Final Drainage Report ' for ShopKo P. U.D. Due to site constraints and the desire to save existing landscaping Basin 6 will also be allowed to release undetained. 4.2 Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. For more specific details see Drainage and Erosion Control Plan located in ' the back packet and Appendix B for calculations. ' Sub -basin 1 contains the central portion of the site including all of the onsite parking lot and a portion of the parking lot north of the site. Runoff from this basin flows to the ' south central portion of this basin to an inlet located at a low point. In the event that this inlet should fail, runoff will overtop at the west entry area and will flow south to ' Boardwalk Drive. This overflow will eventually reach Fossil Creek. Runoff is conveyed to the detention pond through Storm 2. Buildings have been placed at an elevation that will provide protection in the event of flooding. Sub -basin 2 contains the northeast portion of the site including a small area of parking 1 north of the site. Runoff from this basin flows to the southeast comer of this basin to an inlet located at a low point. In the event that this inlet should fail, runoff will overtop the 4 I I CJ 1 C I I curb & gutter and flow south in a swale near the east property line. Runoff will enter Storm I and will be conveyed to the East Pond. Runoff from this basin is undetained and therefore flow is deducted from the allowable release rate for the detention pond. Sub -basin 3 contains the east central portion of the site including half of the east building and landscaped area. Runoff from this basin flows to the south in a swale to the detention pond. Sub -basin 4 contains the southeast portion of the site including the remainder of the east building and the water quality / detention area. Runoff from this basin sheet flows into the detention pond. In the event that the detention pond should overtop, runoff will be conveyed to Boardwalk Drive over the spillway located on the south side of the detention pond. This overflow will flow west in curb & gutter to College Avenue and eventually into Fossil Creek. Sub -basin 5 contains the southwest building. roof drains and discharged directly to Storm 3 runoff to the detention pond. Runoff from this basin will be collected in Stone 3 connects to Storm 2 and conveys Sub -basin 6 contains the south portion of the site and consists entirely of landscaped area. Runoff from this basin will be conveyed south to Boardwalk Drive, west to College Avenue and eventually to Fossil Creek. Runoff from this basin is undetained and therefore flow is deducted from the allowable release rate for the detention pond. Runoff from Basins 1, 3, 4 & 5 enter the onsite detention area. After being detained, the water will enter Storm I and will be conveyed to the East Pond. Release from the East Pond is conveyed to the No. 2 Canal. 4.3 Drainage Summary The storm conveyance system is a surface and sub -surface system and has been designed for minimal maintenance. The proposed storm sewer system and the detention pond will be owned and maintained by the property owner(s). 9 i ' 4.4 Variance Requests No variances are being requested at this time. 1 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. A potential exists for silt movement from the site to be transported into the onsite detention pond located in the southeast portion of the site. All erosion ' control measures necessary to minimize sediment transport have been shown on the Erosion Control Plan. The required performance standard for the site is 81.1%. During ' construction and after paving, this figure has been exceeded with the use of silt fence, inlet filters, straw bales, and by using the detention pond as a sediment trap during construction. All erosion control calculations are included in Appendix D of this report. The erosion control escrow amount is $4,560. ' 5.2 Specific Details ' To limit the amount of silt leaving the site, several erosion control measures shall be implemented during construction. Silt fence shall be installed along the southern, eastern Vehicle be installed the and western sides of the proposed site. -tracking pads shall at entrances to the existing asphalt area to control mud being tracked onto existing pavement. During overlot grading, disturbed areas are to be kept in a roughened condition and watered to reduce wind erosion. ' 5.3 Dust Abatement During the performance of the work required by these plans, the contractor shall cant' out proper efficient measures wherever and as necessary to prevent dust nuisance, which has ' originated from his operations from damaging crops, orchards, cultivated fields and dwellings, or causing nuisance to persons. The Contractor will be held liable for any damage resulting from dust originating from his operations under these plans, on right-of- way or elsewhere. ' 6 I 1 ' 5.4 Tracking Mud ' Wherever construction vehicles access routes intersect paved public roads, provisions shall be made to minimize the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface. A stabilized construction entrance is required per the detail ' shown on the Detail Sheet with base material consisting of 6" coarse aggregate. The contractor will be responsible for clearing tracked mud on a daily basis. ' 5.5 Maintenance All temporary and permanent erosion and sediment control practices must be maintained and repaired as needed to assure continued performance of their intended function. Silt ' fences will require periodic replacement. Maintenance is the responsibility of the contractor. 6. CONCLUSIONS 6.1 Compliance with Standards All computations that have been completed within this report are in compliance with the 1 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 the detention and transmission of developed onsite runoff to the existing storm system. The impact of the development of this site on existing ' downstream facilities is has been minimized. Detention is being provided to meet requirements set by the City of Fort Collins in accordance to the most recent rainfall ' criteria standards. If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit would be required. 1 7 1 1 i 1 1 1 1 1 1 i 1 1 1 1 i 1 i 1 1 6.3 Erosion Control Concept Since the site is less than 5.0 acres, a NPDES permit is not required. During construction, erosion control shall be maintained to minimize erosion on this site and transport of silt downstream. 7. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 1986. 2. The Final Drainage and Erosion Control Report for ShopKo P.UD. by TST, Inc dated May 11, 1993. 3. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3 dated September, 1999. e I 1 1 1 1 rl 1 1 it 1 1 1 1 1 17 1 APPENDIX A VICINITY MAP A 1 PROJECT SITE , iF0_ Am s fi l s� e i t 4a s` n a 6 9 f 1 � a ', VICINITY MAP APPROXIMATE SCALE: 1" = 1000' SHEET 1 OF 1 DATE: 07/15/03 PARCEL •B' (North Star SCALE: 1" = 1000' "1�- design, inc. AT SHOPKO P.U.D. 700 Automation Drive, Unit DRAWN BY: TDS VICINITY MAP Windsor, Colorado 80550 Phone: 970-686-6939 JOB NO.: 170-03 Fax: 970-686-1188 I 1 I I APPENDIX B HYDROLOGIC & HYDRAULIC CALCULATIONS 0 �� pCE9p PUNT Q RJXCff ClYfi%JEHi � AVU w Atl(ES ROF gPECllpl G ....• ...... BA9P BdMDARY �iy` 6P V C fA1FO5ED IWEi N10 %PF .,��� 8 QLL R D Ew MCAOR y� maeo5m Rtz, Eounw 1 mr,,C s'Ow. EM.. I-coxiaw CPCVOSf➢ 5' Cp1q.W mwosEO r cprwe w © a .je(—)�f- 9li RHfl U O min Pxoxcnp > m OParr"MCT0N ENMMCE OYCOIENI MA" O w m 10 o IB 0 SCALE: Y - 20' I I W � e n � D NSTRUCTION SEQUENCE SIYpN•iWlt O N m O ' T. al[RD BI. UR S/31 -ryGT-amNIYVLLn DETENTION POND SUMN DRAINAGE SUMMAF CN Pmi OES3a ANEA OEYG A AMS CO CI.IO.0 7 .N Ow 1.00 a 0.25 o 0,75 o'z os eA 0eO11 s s o.IY O.ap LOO 6 C 0.19 0.]0 O$5 wi..rco e.. o�ea�a W m®m W A� m a rc Q U •WNO1fD BI DIY V Mi V9IIINS p. MZ City of Fort Collins, Colorado < UTILITY PLAN APPROVAL d O APPROVED'. 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LL LL H LL O O O R1 O'1 O� V V F Q O N U K O p = } E 2 � a p U d ON] rn C) (O M GI � rn o of of of of ei a; ai U o 0 o u� o in o 0 N LL _ K Z 2 ¢ F p a m w O Z m m z 0 � o N a O_ Q 0 LL I t 11 I t CURB OPENING INLET IN.A SUMP Project = Parcel " B" at ShopKo P.U.D. Inlet ID = Inlet 1-1 DCSLr POirt F- Z N1rP Lu WP •rate r Yd Flow Direction H Ltr Pan Gutter ign Information (Input) 3th of a Unit Inlet L„ = 5.00 ft aI Depression, if any (not part of upstream Composite Gutter) a,., = 2,00 inches lht of Curb Opening in Inches H = 6.00 inches Width for Depression Pan Wp = 3.00 ft Iging Factor for a Single Unit (typical value = 0.1) Co = 0.10 le of Throat (see USDCM Figure ST-5) Theta = 63.4 degrees ce Coefficient (see USDCM Table ST-7) Cd = 0.67 r Coefficient (see USDCM Table ST-7) Cw = ,3.00 it Number of Units in the Curb Opening Inlet No = 1 a Weir :ign Discharge on the Street (from Street Hy) Qa = 3.0 cfs ter Depth for the Design Condition Yd =' . 6.83' inches al Length of Curb Opening Inlet L = 5.00 ft )acity as a Weir without Clogging QM = 13.4 cfs gging Coefficient for Multiple Units Coef = - 1.00 gging Factor for Multiple Units Clog =.. 0.10. )acity as a Weir with Clogging Q� 12.8•cfs an Orifice )acity as an Orifice without Clogging Qa = 7.9 cfs )acity as an Orifice with Clogging Qua = 7.1 cfs )acitvfor Design with Clogging Qa=. M, 7.1?cfs )ture Percentage for this Inlet = Qa / Qo = C%= _°100.00,% Note: Unless additional ponding depth or spilling over the curb is acceptable, a capture percentage of less than 100% in a sump may indicate the need for additional inlet units. ' Inlet1-1.xls, Curb-S 7/10/03, 2:57 PM .'COMBINATION INLET IN A SUMP Project = Parcel "B" at ShopK6 P:U.D. Inlet ID =Inlet 2-1 Design Point 1 L WP Will ><-----'<---> � Fto v Direction Curb H Ciro r � - `frb Design Information (Inputl Length of a Unit Inlet L, = 3.33- ft Local Depression, it any (not pan of upstream Composite Gutter) a„ ,d = 2.00 inches Number of Unit Inlets No= 1 Grate Information �. Width of a Unit Grate Wa = 2.00 ft Area Opening Ratio for a Grate (typical values 0.60-0.90) A = 0.36 Clogging Factor for a Single Grate (typical value 0.50) C, (G) = 0.50 Grate Onfice Coefficient (typical value 0.67) Ca (G) = 0.67 Grate Weir Coefficient (typical value 3.00) C.(G)= 3.00 Curb Opening Information Height of Curb Opening in Inches H = 6.00 inches Angle of Threat (see USDCM Figure ST-5) Theta = 64.3 degrees 1 Side Width for Depression Pan W, = 3.00 it Clogging Factor for a Single Curb Opening (typical value 0.10) C. (C) = 0.10 Curb Opening Orifice Coefficient (typical value 0.67) C, (C) = 0.67 G Curb Opening Weir Coefficient (typical value 2.30-3.00) C„. (C) = 2.30 Design Discharge on the Street (from Street Hy) 0,= 11.8 cfs Water Depth for Design Condition V, = 6.5 inches Total Length of Combination Inlet L = 3.33ft As a Weir Capacity as a Weir without Clogging O„ = 13.2 cis Clogging Coefficient for Multiple Units Coef= 1.00 Clogging Factor for Multiple Units Clog = 0.50 Capacity as a Weir with Clogging 0„,=; '10.2 cfs As an Orifice Capacity as an Onfice without Clogging Oa = 10.9 cfs Capacity as an Orifice with Clogging O„ = 5 d. cfs Grate Capacity for Design with Clogging Curb Opening Inlet Capacity in a Sump As a Weir Capacity as a Weir without Clogging Ow=-' 12.0 cfs Clogging Coefficient for Multiple Units Coef= 1.00 Clogging Factor for Multiple Units Clog= 0.10 �I Capacity as a Weir with Clogging 0,,, = 1116 cfs As an Orifice Capacity as an Onfice without Clogging 0. = 6.2 cfs Capacity as an Onfice with Clogging O„ = 5.6 cfs Curb O enin Canacith, for Design with Clogging O,i,,,,=. 5.61 cfs Combination Inlet Capacity with Cleaning 0,= -- 1.t.0ids _ Capture Percentage for the Combination Inlet C % =. 93.64' % Note: Unless addifional pending depth or spilling over the curb is acceptable, a capture percentage of less than 100 % in a sump may indicate the need for additional inlet units. 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L E y J (n A c O a) W O O O O O O O O 00 � O Ln � M 0 0 0 0 0 0 0 Ln Ln Ln Ld Ln Ln Ln O m N O Ln r M Ln 0 00 Lr U N CO ,� m o d O Qi�O❑° o NCCM—O J�C) (j d3 5 m Mo t� O N Z y Y OO m r cn J N O L N U N x 0 N LO N O O A L Lo Ln U a) ; � O ❑o� Y a /LL W c C O /w L0. a M CO NO �o L o 2 y d mrN 1- c� Project Description Worksheet East Swale Calculi Flow Element Triangular Channe Method Manning's Formula Solve For Channel Depth Section Data Mannings Coeffc 0.030 Slope 010000 ft/ft Depth 0.49 It Left Side Slope 4.00 H : V Right Side Slope 4.0 Discharge 1.86 cfs East Swale Cross Section for Triangular Channel l34 s,ti 3 F-Loc,j 7-o LJOeTe, -ritow po"i 0.4a, FT ; I.Q - ar O lL 0.49 ft VAN HA NTS Project Engineer: North Star Design, Inc uA170-03 parcel b - shopko\drainage\swale.fm2 North Star Design, Inc FlowMaster v6.1 [614n] 07/10/03 03:05:27 PM O Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA (203) 755-1666 Page 1 of 1 East Swale x 1.33 Cross Section for Triangular Channel Project Description Worksheet East Swale Calculation Flow Element Triangular Channel Method Manning's Formula Solve For Channel Depth Section Data Mannings Coeffic 0.030 Slope 0 Depth ( 0.55 ft Left Side Slope 4�0 H : V Right Side Slope 4.00 H : V Discharge 2.47 cfs ,B',SI J -7 pee/I /zL)N4 u ).33 LD ' nn 6 C 51 9 n1 0.55 ft VA H:1 NTS Project Engineer: North Star Design, Inc u:\170-03 parcel b - shopko\drainage\swale.fm2 North Star Design, Inc FlowMaster v6.1 [614n) 07/10/03 03:05:52 PM O Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA (203) 755-1666 Page 1 of 1 I 1 I 1 APPENDIX C IDETENTION AND WATER QUALITY CALCULATIONS 1 Imo, L� i I C] 1 1 1 i I 1 I 1 [ 1 I 7/10/03 I 11 t U 1] I I I I LOCATION: Shops at ShopKo ITEM: Water Quality Pond Sizing COMPUTATIONS BY: TDS SUBMITTED BY: North Star Design, Inc From Urban Strom Drainage Criterial Manual, September 1999 Use 40-hour brim -full volume drain time for extended detention basin Water Quality Capture Volume = WQCV = (required storage/12)'(tributary drainage area) MAJOR BASIN Trib. area (ac) % Imperv. Req. Storage (in. of runoff) from Fig. SQ-2 WQCV (ac-ft) DWQ (it) req. vol WQCV •1.2 (ac-ft) req. area/row (inr/row) from Fig. RP-3 POND #1 1.85 87.0 0.38 0.058 3.82 0.070 0.22 WQ outlet sizing for pond 1 From Figure 5, for 1/2 in. hole diameter Area of hole = 0.20 in # of columns = 1 Area provided/row = 0.20 in Area Required/row = 0.22 in Use 1 columns of 112" diam holes WQVOL.xls DETENTION POND SIZING BY FAA METHOD Developed by Civil Eng. Dept., U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study Denver Urban Drainage and Flood Control District, Colorado EXECUTED ON 07-16-2003 AT TIME 07:52:23 PROJECT TITLE: TYPE IN THE PROJECT TITLE **** DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER = 1.00 BASIN AREA (acre)= 1.85 RUNOFF COEF = 1.00 DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) = 100.00 INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 150 180 INTENSITY 9.9 7.7 5.6 4.5 3.7 3.2 2.9 2.4 2.1 1.8 1.2 1.0 ***** POND OUTFLOW CHARACTERISTICS: MAXIMUM ALLOWABLE RELEASE RATE = 17.25 CFS OUTFLOW ADJUSTMENT FACTOR .765 AVERAGE RELEASE RATE = 13.19625 CFS ' AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. ***** COMPUTATION OF POND SIZE OU Lc-' Ca.% //�� - o _�'''�;,,� __ __--- Alow6.6IeG i 21.44 RAINFALL RAINFALL______INFLOW_OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE _ 3.07- MINUTE INCH/HR ACRE -FT ACRE -FT ACRE -FT --------------------------------------------------_ __ - 0.4zz 0.00 0.00 0.00 0.00 0.00 aq S,N ` = 5.00 9.95 0.13 0.09 0.04 10.00 7.72 0.20 0.18 0.02 c� 15.00 6.66 0.26 0.27 0.00 20.00 5.60 0.29 0.36 0.00 TioJ 4 eyi4riNj 25.00 5.06 0.33 0.45 0.00 30.00 4.52 0.35 0.55 0.00 35.00 4.13 0.37 0.64 0.00 - - --- /`J.ZS CFS THE REQUIRED POND SIZE _ .0269466 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 5 MINUTES at rO(L P.. Pjoh ] BG(V VC C 5 DN V F K PKwh 11 Parcel " B" at ShopKo P.U.D. Proposed Detention / Water Quality Pond - Stage/Storage LOCATION: Shops at ShopKo PROJECT NO: 170-03 COMPUTATIONS BY: TDS SUBMITTED BY: NORTH STAR DESIGN, INC. DATE: 7/16/03 V = 113 d (A + B + sgrt(A'B)) where V = volume between contours, ft3 d = depth between contours, ft A = surface area of contour Water Quality Volume Required = 0.070 Acre -Feet Detention Volume Required = 0.037 Acre -Feet Total Volume Required = 0.107 Acre -Feet WQCV 100 YR WSEL Overflow e/ev Stage (ft) Surface Area (ft`) Incremental Storage (ac-ft) Total Storage (ac-ft) 42.30 0 43.0 594 0.00 0.003 44.0 823 0.02 0.019 45.0 1059 0.02 0.041 46.0 1353 0.03 0.069 46.04 1393 0.001 0.070 46.91 2268 0.037 0.107 47.0 2358 0.00 0.112 ` 48.0 4281 0.08 0.187 detention.xls I Parcel "B" at ShopKo P.U.D. Detention Pond Outlet Sizing (100 yr event) LOCATION: Shops at ShopKo PROJECT NO: 170-03 COMPUTATIONS BY: TDS SUBMITTED BY: North Star Design DATE: 7/ 16/03 Submerged Orifice Outlet: release rate is described by the orifice equation, Qo = C,k sgrt( 2g(h-E,)) where Qo = orifice outflow (cfs) Co = orifice discharge coefficient g = gravitational acceleration = A. = effective area of the orifice (ft`) Eo = geometric center elevation of the orifice (ft) In = water surface elevation (ft) Pond Outlet Qo = 17.25 cfs outlet pipe dia = D = 30.0 in Invert elev. = 5042.30 ft Ea = 5043.04 It ' h= 5046.91 ft-WSEL Co = 0.64 I I solve for effective area of orifice using the orifice equation A. = 1.707 ft` = 245.9 in` orifice dia. = d = 17.69 in 32.20 ft/s Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering) d/ D = 0.59 kinematic viscosity, v = 1.22E-05 ftz/s Reynolds no. = Re, = 40/(ndv) = 1.22E+06 Ce = (K in figure) = 0.64 check Use d = 17.7 in Ao= 1.709 h`= Qmax = 17.26 cis 246.06 in detention.xis Parcel "B" at ShopKo P.U.D. Emergency Overflow Spillway Sizing LOCATION: Shops at ShopKo PROJECT NO: 170-03 COMPUTATIONS BY: TDS SUBMITTED BY: North Star Design DATE: 7/16/03 Equation for flow over weir Q = CLH3n where C = weir coefficient = 3.1 H = overflow height L = length of the weir Spillway will be designed with max 0.5 It flow depth, H = 0.5 It Size the spillway assuming that the pond outlet is completely clogged. Q (100) = 21.4 cfs Spill elev = 5047.00 ft Min top of berm elev.= 5048.00 Weir length required: L = 20 ft Use L = 20 ft v = 1.82 ft/s too o4 berm b *-pull elevation L —► p 100 yr WSEL 100 yr WSEL = 5046.91 ft detentionAs L� I I 1 I L LJ APPENDIX D EROSION CONTROL CALCULATIONS F7 0 N ^ o a - W Q a Qo z 4 vFi C a � 0 N a - N V a N b r r r- ry r/Aj ' (V N Cl fV Cl M a U m M N N m m n N v� o. W z a� d O G W ° Oq A L � c .E T � P H N yA C � N �A �+ N U .y � W N O c4 .— W a C A E U o w O 7 - > C L m P P D P a ❑ e 7 O n X y II II p p Q o--1 Vl it it —i VI = w` cn c C. Q x 0 w ' North Star Design 700 Automation Drive, Unit I ' Windsor, CO 80550 EFFECTIVENESS CALCULATIONS F 1 1 11 PROJECT: SHOPKO PUD STANDARD FORM B COMPLETED BY: PPK DATE: 23-Feb-04 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) 1 1.18 BARE SOIL 0.00 Ac. ROADS/WALKS 1.11 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.05 Ac. ESTABLISHED GRASS 0.02 Ac. C-FACTOR 0.05 P-FACTOR rEFF 0.40 = (I -C'P)' 100 = 97.9% 2 0.30 BARE SOIL 0.00 Ac. ROADS/WALKS 0.29 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.01 Ac. ESTABLISHED GRASS 0.00 Ac. NET C-FACTOR 0.04 NET P-FACTOR 0.40 EFF = (I-C'P)' 100 = 98.3 % 3 0.25 STRAW BARRIERS 0.11 Ac. ROADS/WALKS 0.00 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.14 Ac. ESTABLISHED GRASS 0.00 Ac. NET C-FACTOR 1.02 NET P-FACTOR 0.36 EFF = (I-C'P)'100 = 63.3% 4 0.23 BARE SOIL 0.00 Ac. ROADS/WALKS 0.00 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.23 Ac. ESTABLISHED GRASS 0.00 Ac. NET C-FACTOR 1.00 NET P-FACTOR 0.36 EFF = (I-C'P)' 100 = 64.0% ' Erosion.xls 2 of 5 North Star Design 700 Automation Drive, Unit I Windsor, CO 80550 PROJECT: SHOPKO PUD STANDARD FORM B COMPLETED BY: PPK DATE: 23-Feb-04 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 0.19 BARE SOIL 0.00 Ac. ROADS/WALKS 0.00 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.19 Ac. ESTABLISHED GRASS 0.00 Ac. NET C-FACTOR 1.00 NET P-FACTOR 0.36 EFF = (I-C*P)* l00 = 64.0 6 0.19 BARE SOIL 0.00 Ac. ROADS/WALKS 0.00 Ac. STRAW MULCH 0.00 Ac. SEDIMENT BASIN 0.19 Ac. ESTABLISHED GRASS 0.00 Ac. NET C-FACTOR 1.00 NET P-FACTOR 0.36 EFF = (I-C*P)* 100 = 64.0 TOTAL AREA = 2.34 ac TOTAL EFF = 85.4% _ (94.0 % *29.77 ac. + .. +99.6 % *0.40 ac)/1.14 ac REQUIRED PS = 81.1 Erosion.xls 3 of North Star Design 700 Automation Drive, Unit I Windsor, CO 80550 CONSTRUCTION SEQUENCE STANDARD FORM C PROJECT: SHOPKO PUD COMPLETED BY: PPK DATE: 23-Feb-04 Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an approved schedule may require submitting a new schedule for approval by the City Engineer. • rr- rr �©©o©000©o©o Demolition Grading Soil Roughing Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other Rainfall Erosion Control Sediment Trap/Basin Inlet Filters Straw Barriers Silt Fence Barriers OtherWind Erosion Control: Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving Other Permanent Seed Planting Temporary Seed Planting nkets . -.BUILDING CONSTRUCTION STRUCTURES: INSTALLED BY: CONTRACTOR MAINTAINED BY: DEVELOPER VEGETATION/MULCHING CONTRACTOR: TO BE DETERMINED BY BID DATE SUBMITTED: 10-Mav APPROVED BY CITY OF FORT COLLINS ON: Page 4 Cost Est I EROSION CONTROL COST ESTIMATE Project: SHOPKO PUD Prepared by: PPK ITEM IQUANTITY JUNIT COST/UNIT ITOT77FOST Silt Fence 730 LF 1 $3 $2,190 Straw Bale Barrier 0 EA $150 $0 Gravel Inlet Filter 2 EA $150 $300 Construction Entrance 1 EA $550 $550 Subtotal Contingency (50%) Total $3,040 $1,520 $4,560 CITY RESEEDING COST Reseed/Mulch 1.8 ACRE $650 $1,170 Subtotal Contingency (50%) Total $1,170 $585 $1,755 EROSION CONTROL ESCROW AMOUNT $4,560 1 Page 5 7/16/03 1 1 1 1 1 1 1 Riprap Calculations for Circular Pipe Outlets LOCATION: Parcel "B" at ShopKo P.U.D. PROJECT NO: 170-03 COMPUTATIONS BY: TDS SUBMITTED BY: North Star Design DATE: 7/ 16/03 From Urban Strom Drainage Criteria Manual volume 2, June 2001 (Referenced figures are attached at the end of this section) Q = discharge, cfs D = diameter of circular conduit, ft d = tailwater depth, ft Pd = riprap sizing design parameter V = design flow velocity at pipe outlet, Ills g = accelleration due to gravity 32.2 ft/sec2 Storm 2 24" RCP Q = 13.66 cfs D= 24 in = 2 It a c (30 5 1 d = 4.19 ft From StormCad Model V = 4.4 ft/s From StormCad Model /jH Sr S Pd = (V 2 + g'd)'5 = 12.4 (From Figure HS-20, use Type L riprap) Riprap Depth: From Table HS-9, D50 = 9 in From Equation HS-17. Riprap depth = 1.75' D50 = 16 in Basin Depth: From Equation HS-18a. Basin depth = 0.5 ` D = 12 in Basin Length: From Equation HS-18, L = 4 ' D = 8.0 ft From Equation HS-19, L = D 5V/2 = 3.1 ft Basin Width: From Equation HS-20, W = 4 ' D = 8.0 ft Depth of Cutoff Wall: From Equation HS-22, B = D/2 + 1.75 ' D50 = 2.3 ft Riprap.xls USE: 8' W x 8' L x 16" Type L Riprap wl 12" Basin Depth & 6'x 2.5' Cutoff wall Page 1 I 1 1 APPENDIX E FIGURES AND TABLES 1 I 1 I 7 11 I STREET/INLETS/STORM SEWERS DRAINAGE CRITERIA MANUAL (V. 1) I 1 TABLE ST-7 Sag Inlet Discharge Variables and Coefficients (Modified From Akan and Houghtalen 2002) Inlet Type C L Weir Equation Definitions of Terms Valid For Grate Inlet 3.00 L + 2W d < 1.79(AJL ,) L = Length of grate W = Width of grate d = Depth of water over grate Ao= Clear opening area Curb Opening 3.00 L d < h L = Length of curb opening Inlet h = Height of curb opening d = d, — (h12) d; = Depth of water at curb opening L + 1.8W d < (h + a) W = Lateral width of depression Opening Inlet3 a = Depth of curb depression Slotted Inlets 2.48 L d < 0.2 ft L = Length of slot d = Depth at curb The weir length should be reduced where clogging is expected. 2 Ratio of clear opening area to total area is 0.8 for P-1-7/8-4 and reticuline grates, 0.9 for P-1-7/8 and 0.6 for P-1-1/8 grates. Curved vane and tilt bar grates are not recommended at sag locations. 3 If L > 12 ft, use the expressions for curb opening inlets without depression. Co Ao° Orifice Equation Definition of Terms Valid for Grate Inlet 0.67 Clear d > 1.79(Ao/L„) d = Depth of water over grate opening areas Curb Opening d; > 1.4h d = d; — (h/2) Inlet (depressed d; = Depth of water at curb opening or undepressed, :0.67?h)(L) h = Height of curb opening horizontal orifice throae) (W) d > 0.40 ft L = Length of slot W = Width of slot d = Depth of water over slot 4 The orifice area should be reduced where clogging is expected. 5 The ratio of clear opening area to total area is 0.8 for P-1-7/8-4 and reticuline grates, 0.9 for P-1- 7/8 and 0.6 for P-1-1/8 grates. Curved vane and tilt bar grates are not recommended at sag locations. 6 See Figure ST-5 for other types of throats. 3.3.6 Inlet Clogging. Inlets are subject to clogging effects (see Photographs ST-5 and ST-6). Selection of a clogging factor reflects the condition of debris and trash on the street. During a storm event, street inlets are usually loaded with debris by the first -flush runoff volume. As a common practice for street drainage, 50% clogging is considered for the design of a single grate inlet and 10% clogging is considered for a single curb -opening inlet. Often, it takes multiple units to collect the stormwater on the ST-24 06/2001 Urban Drainage and Flood Control District STORMWATER QUALITY MANAGEMENT DRAINAGE CRITERIA MANUAL (V. 3) 0.50 0.45 0.40 d 0.35 U 0.30 D t 0.25 is 3 0.20 V 3 0.15 0.10 0.05 0 00 40-hour Drain Tim 24-hour Drain Time WQCV=a'(0.glil -1. 19i2+0.781) 6-hr drain time a = 0.7 12-hr drain time a = 0.8 24-hr drain time a = 0.9 40-hr drain time a = 1.0 12-hour Drain Time i 6-hour Drain Time 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Total Imperviousness Ratio (i = 1,,.q/100) FIGURE SQ-2 Water Quality Capture Volume (WQCV), 80`h Percentile Runoff Event 14 SQ-24 9-1-99 Urban Drainage and Flood Control District ' DRAINAGE CRITERIA MANUAL (V. 3) STORMWATER QUALITY MANAGEMENT ' WQCVo -de W Q CV 0.43 in which, ' WQCVo = Water quality capture volume outside the Denver region d6 = Depth of average runoff producing storm from Figure SQ-3 (watershed inches) ' Once the WQCV in watershed inches is found from Figure SQ-2, then determine the required storage volume in acre-feet as follows: ' Requiredstorage=rW 2 l(Area) ' L 1J in which, Required storage Required storage volume in acre-feet Area — The tributary catchment's area upstream in acres ' The independent variable in Figure SQ-2 is the total imperviousness ratio (i.e., =1w,�l00) of the tributary watershed (catchment). The chapter on Runoff in Volume 1 of the USDCM contains guidance for how to ' find the total imperviousness of a watershed and its use is recommended with one exception. Figure 2-1 in Runoff chapter of Volume 1 relate housing density to the impervious area percentage is no longer valid. Instead use Figures SQ-4, SQ-5 and SQ-6 to estimate the imperviousness of single family residential areas. Note that these figures require the knowledge of the average housing densities, types of housing, and their average square footage to find the imperviousness of these areas. I I 9-1-99 SQ-23 Urban Drainage and Flood Control District Orifice Plate Perforation Sizing Circular Perforation Sizing Chart may be applied to orifice plate or vertical pipe outlet. Rm- Hole Dia (in) ` Hole Dia (in) Min. Sc (in) Area per Row (sq In) n=1 n=2 n=3 1 4 0.250 1 0.05 0.10 0.15 5 16 0.313 2 0.08 0.15 0.23 3/8 0.375 2 0.11 0.22 0.33 0.30 0.45 1/2 0.500 2 0.20 0.39 0.59 0.50 0.75 5/e 0.625 3 0.31 0.61 0.92 11116 0.688 3 0.37 0.74 1.11 3 4 0.750 3., 0.44 0.88 1.33 13 16 0.813 3 0.52 1.04 1.56 7 8 0.875 3 0.60 1.20 1.80 15 16 0.938 3 1.38 2.07 . 1 1.000 4 1.57 2.36 1 1 16 1.063 4 1.77 2.66 1 1 8 1.125 4 1.99 2.98 1 3 16 1.188 4 P123 2.22 3.32 1 t 4 1.250 4 2.45 3.68 1 5 16 1.313 4 2.71 4.06 1 3 8 1.375 4 2.97 4.45J716 1.438 4 3.25 4.87 1.500 4 . 3.53 5.30 1.563 4 1.92 3.83 5.75 1.625 4 2.07 4.15 6.22 1.688 4 2.24 4.47 6.71 1.750 4 2.41 4.81 7.22 1.813 4 2.58 5.16 7.74 1.875 4 2.76 5.52 8.28 1.938 4 2.95 5.90 8.84 2.000 4 3.14 6.28 9.42 n = Number of columns of perforations Minimum steel plate thickness 1/4 ' 5/16 ' 3/8 Designer may interpolate to the nearest 32nd inch to better match the required area, if desired. Rectangular Perforation Sizina Only one column of, rectangular perforations allowed. Rectangular Height = 2 inches Required Area per Row (sq in) Rectangular Width (inches) _ 2" Urban Drainage and Flood Control District Drainage Criteria Manual (V.3) rs.: o.t.r.d.o GO�iINAI� top Z Rectangular Hole Width Min. Steel Thickness 5" 1 4 6" 1 4 7" 5/32 8" 5/16 9" 11 /32 " 10" 3/8 , >10" 1/2 , Figure 5 WOCV Outlet Orifice Perforation Sizing apter 5 Closed Conduit Flow 1n� In'- 1.2 ' 1.1 ' 1.0 ' 0.9 K ' 0.8 ' 0.7 0. Re _ V2gOh d K 103 104 105 106 '■I�III�NI�NI�N1�11 Venturi meters and nozzles I ' fl 1 1 1'\11�� • vOrifices I ` 1 :1 0.40 Mm K a R, S4 � / 1 V. 10� 102 10` 10410 __ 4Q Red Trdv L ZZ Y/o� Figure 5-21 Flow coefficient K and RedlK versus the Reynolds number for orifices, nozzles, and venturi meters (20, 23) 1 - �T- '.7 r7 L 7 L 'mil 11 'J Fl L I LI APPENDIX F EXCERPTS FROM PREVIOUS REPORTS F No Text ' where L is the length of overland flow in feet (limited to a maximum of 500 feet), S is the average basin slope in percent. 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. ' DRAINAGE PLAN DEVELOPMENT ' The proposed drainage plan for the development consists of a combination of sheet flow, across a paved parking lot, collection into inlets, and conveyance to and from detention ' facilities via storm sewer pipe. This project will also include construction of the west half of JFK Parkway from Boardwalk Drive to Bockman Drive. Street flows for this portion of the site will be calculated based on encroachment criteria set forth in the SDDC manual for ' an arterial roadway. The other three streets which bound the site will also be evaluated based on the SDDC criteria set forth for their respective classifications. ' Although this site lies in two major drainage basins, the City of Fort Collins Stormwater Utility is requiring that all runoff from the site be detained and then released into the Larimer ' #2 canal. Temporary facilities are currently under construction as part of the JFK Parkway extension to Bocicman Drive. These facilities include two detention ponds, one of which is on the ShopKo site at the southwest corner of Boclunan Drive and JFK Parkway. This pond ' is referred to as Pond "A" in the JFK Parkway Drainage Report. The other pond is referred to as Pond "B". In that report, runoff from 5.77 acres of the ShopKo site was to be detained in Pond "A" and released at a rate of 5.02 cfs via a 15" RCP into Pond "B". To avoid ' obtaining a separate release permit into the Larimer #2 Canal to accommodate the remainder of the ShopKo site, it was decided to detain all runoff and release it through Pond "A" at the predetermined rate of 5.02 cfs. PROPOSED DRAINAGE PLAN ' Preparation of the drainage plan required the delineation of sub -basins within the development. It should be noted that the labels for the sub -basins and storm drainage facilities has changed considerably from the preliminary report; however, the drainage plan has changed very little. The grading and drainage plan can be found at the end of this report ' and shows the sub -basin delineation and proposed storm drainage facilities. Calculations made for flow, inlet, detention pond, pipe analysis, street capacity and riprap design can be found in the Technical Appendix. The results of these calculations can be found in Tables ' 1, 2, 3, 4, 5 and 6 at the end of this section. A summary of the Proposed Drainage Plan for each sub -basin is provided in the following paragraphs. ' Sub -basin A includes runoff from the parking lot and future building pad on the south side of the ShopKo building. Runoff will sheet flow around the east and west sides of the future building pad and directed into swales in the parking lot. A swale on the east side of the pad t 6 :i I I 1 will direct runoff directly to area Inlet #1. A combination of swale and gutter flow will also direct runoff to Inlet #1. Critical sections in the swales were checked to insure that runoff would not leave the site or spill into adjacent sub -basins. This check was also needed to insure that emergency vehicles could gain access to the future building during the 100-yr storm. Inlet #1 will be an area inlet in a sump condition. To maximize the inlets efficiency runoff will be allowed to pond to a depth of 0.63 ft. (top of curb). _ The developer is currently negotiating with a potential owner for the building site in this sub -basin and it is anticipated that it will be built concurrently with the ShopKo site. In case there is a delay, this area will be rough graded to insure the runoff will be directed to the inlet. The surrounding curb and gutter and a temporary asphalt trickle pan designed to carry the 2-year storm will be installed. It is also possible the new owner will want to reconfigure the interior curb and gutter. This should not be a problem as long as the runoff is allowed to travel around both sides of the building and not concentrated any more than it is now along the southwest portion of the building pad. Sub -basin B collects parking lot runoff adjacent to the southeast portion of the ShopKo building. Runoff will be directed to curb Inlet N2, which is in a sump condition, via sheet flow and gutter flow. Runoff can only be allowed to pond to a depth of 0.40 ft to insure that it doesn't spill over into Sub -basin C. Sub -basin C collects runoff from the remaining parking lot area on the east side of the ShopKo building and from the west half of. the JFK ROW from the top of the hill to bock man drive. The runoff will be directed to Inlet #3 which is a 35 foot continuous grade curb inlet. The inlet will intercept 100 % of the 100-year storm. Sub -basin D is a landscaped strip between the north side of the ShopKo building and the Bockman Drive ROW. Runoff from this area will sheet flow into Bockman Drive and be collected at Inlet N4 which is a 4-foot continuous grade curb inlet. The street flows have been dealt with in the Toys-R-Us drainage plan and will be collected by an existing inlet and directed into the Toys-R-Us detention facility. Sub -basin E is the east pond. This pond is referred to in the JFK Drainage Report as Pond "A". Final design of this pond differs from the JFK Pond "A" in configuration and capacity but the release rate will be maintained as well as the pipe alignment and release structure. This pond accepts runoff from Sub -basins A, B, C, D, E, and L. It will also receive the release from the west pond. The outlet will release at a rate of 5.02 cfs and the 100-yr ponding depth will be 8.93 feet (EL = 36.31), top of pond EL = 39.0, and there will be 2.69 foot of freeboard. Sub -basin L will collect runoff from the west half of the JFK Parkway ROW between the top of the hill and Boardwalk Drive. Runoff will be directed to Inlet #5 via curb flow. This inlet is a continuous grade curb inlet which will intercept 2.21 cfs while 0.55 cfs will pass during the 100-yr storm. The passing flows will enter Boardwalk Drive in Sub -basin M which will be discussed later. 1 7 '' i J 3 S z N o m r V N r rn m a m 7 N O � O rn W L 7 T -+ N O H1 O�l � y N V .-• N �O a C aO '-I rrr"tJiii U .� a m m o •.• �, w m m r b h m q vv or o ov rc�oror o rr N m ^ V) a wao�_ a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N N N N N N Cl! N N N N N N N N N y L � t a o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 wy V) V) V1 V) V) V) V) V1 V1 V) V) V1 V) V) V) V) L Ir t � C r O m b b a O T g N oo m O V1 b ao N O 7 C �O S m ..+ N n) fV C Vi fV m Vi N fV ^+ O CJ V) z y C pE.,00•E � a W0-G wag ��gam vknv 8 Cii, Iq In z ? N m to tV O Vi m v in Cl to '+ O (V vi U y C y F a x & w s w a m EvISMI.Jg •. AST. PC &istiq Pp e And 15" RCP With Orifice Plate K!/ Be i-ad led By Others Along With The Extens+dn 4 ✓FK Parkway To Backman Dr. Contractor Sol/ Verify ZOCGhon An EAST POND Capacity= 40,565 c.f. V r Inlet 3 100 yr Depth= 8.93' Install 36' Standard 100 yr HW EL= 36.31 Inflow= 4346 cfs v Type "R" Inlet Release= 5.02 cfs , Instal/ Grovel - - Top Of Pond EL=39.0 Inlet Filter Inlet �2 Instal/ IC' Stondardt Type "R" Inlet - 7e 15" RCP r „�•• O� W/ FE.S _ ��•• . N a 35 L.F. 15" RCP 44- RCP W/ Fcc-S � 14 • Instal/ Type "L" Install 4' Diom.••'• /�6 Burned Riprop. See Detail Sheet. (^= Drop, M.H. • •, 1 06 Ac. ' 4' M. H. CONSTRUCTION LIMI.r LINE _.' I 1. Inlet Filters Are To Be Installed As Soon As The The Inlet /s Anstalled. -gnn-� To Be Insto. r_ - Building Pot The Filters , Ioy Be Removed For Final Subgrode Piep Before Paving 'But Are Ta Be Replaced ff Any Area Which Oroins To It /s Not Paved Proposed xl 0 30 fie Or Revegtci ed. 2. the Controc for Shall Be Responsible For Maintaining The Erosion Contra/ ecoia i'-3o' teat Facilities Fo ' As Long As They Are Needed. Control Facilities Should Keep Sediment Out Of The Storm The Erosion Sewer Syste m But If Sediments Do Collect In The Pipes, Ponds, Or ln/ei s \ The Contrac tar Shall Remove And Dispose Of Them Before They Will Be Accept& ' By The 'by'�Stomr Water Utility. Easements Move Been Gropfed To The City Of fort Co//ins Stamn Water Utility For A // Drainage Facilities However /t Will Be The Responsibility Of Tempor The Land O wner To Maintain All Facilities. - Instal/ Grave/ Sway All Pertinon, Stormwafec'Discharge Permits Wilf Be Aquired Before Consf vction Area Inlet Begins. Filter As Soon 6. A/l Disturbe, t Areas Not Being Paved Or Sodded Shall Be Reseeded As The Inlet And Mulch, t With An Equal Mix Of B/ye Gramo And Wester Wheotgross Ori/led /s Installed At A Rote L V 11.40 PLS/Ac.. This Includes The Two Futpre Bui/ding Poo . Install Grovel Inlet Z1 Inlet Filter Instal/ 1 Area . See Detail. Sheet. Sheet. I Inlet /5 •• �'• _� �_ Instal/ 15' Standard Type ��-��'•�• . 5� Standardart Inlet / ac - i 0 y Instal/ Temporary Asphalt Swale • i �� M.H. 12 � --Instal/ 4' Diam. t Standard MH. 25 L.F. 15-RCP i. Sft.•. ,� M serreR Instal/ Temporary Asphalt Swo/e RC,o Shoal" Se, aonsrrucnon A .33 Ac. 17lTURB P.CD i 6zWV = 5050 00 This Building And The Adjacent . Curb And Cutter Will Be Constructed Together toter However This Area is To Be Rough Graded To Contain And Direct Runoff To Inlet1. — — —7. 68.Z In .— /— std Temporary Aso a/t Swole " I� 1 i r 0 i i CALL UTILITY NOTIFICATION CENTER Lf CALORADO 1-800IO922 W 1987 (8yy 2.yYINEe9 Do" N ADVANCE DBLTE VW Did, 4vADE. OR E%fiVA1E aGv 'HE bwINOOF LIYIFA. I�` - T it STANDARD F CONTROL R] JoTM ' 11 0''996 m hot to If r 9 blgroogr Oro, ., J 'I III 1 awbe no I Pro, rep 1.18 to the are, 0.9 ` `II - ._ - m.MI,,. M or 1 0.70 0. I" II }\\ l Hil � I Lu vw 11 j I 11 x I ti W ( _ >rc�...` OI \il i113 jl 7 0.1950.95 EX I STING TWI2'Yu 6Gq y�,Dw q� for or, 150 YR HWEL 5OM691 MAX RELEASE RATE 17.25 DES DRAINAGE SUMMARY TABLE DESIGN POINT AREA AREA DESIG, ACRES CIO C100 Tc j10J IN Tc (100J MIN O (10) CFS 0 (1W) CES COMMENTS 1 1 1Is 0.92 1.W 5.0 5.0 5.29 11.J9 2 2 0.30 0.90 1.00 i0 SO 1.32 1 3.02 1 UNDETAINEO FLOW 3 3 0.25 0.60 075 .0 5.0 073 1.86 4 s 0.23 0.60 0.81 5.0 5.0 O 71 1.82 5 5 0.19 0.9E 1.00 5.0 5.0 0,87 1.87 5 fi 0.19 0.20 0.25 J.0 6J O.Ifi 0<2 UNDETAINED FLOW v yin-YrInt Pill 1 On In SEE DETAIL SHEET wERCfTHCY vlLLW y SEE wR N6 SITE! 11 H. CE 1 I In I� j I I ' rt LL SILT FENCE CONY SCCWWEST EOLE OF 3 a wdom��HY_ Z IYq F .°. Sole, Y I I at DOI 0, 2 SFS _. S B s F gBnes O 5 B9 cr oe A� 'jr,- FFOR S EENUEX SECTIdI seen 100 YW 141MCL-5048.91 PwEEYE Swe Ip9 Fo "ea°/Eeax:r �I SEA1.tm Wild pre1 Oon,"Ye > I., jf I0j fe FA11YH6 CWSW 'r If 1 1 smucnREs )1 HCETATONEWUL 11t, DATE sL'BNITIEP. s1RUCNRE SHEETS F �\ y1✓L�+E' �mttieY �/1, DETENTION POND �p PRIM RAD TO COMIAE INS LALL 9LL FpcE \her I p W NCRTN seDE 2, DETENTION POND CeW u I EXCAVATED BY 2 I) AS A SEDIMENT CONSTRUCTION. \ 3, PRIM TO LANDS TEE TOP OF FpIMDATIW ELEVAMRKS Sxobl ARE THE MMWI ar POND SHALL BE EIEVATp41EpIIRFD FORE PROFECTM PRIM M IW-YFM WADES SHOWN ri e`er \ SFUOI. W WUM FINISHED ROCK ELVATM ABJK ME 1C0-FEAR WATER SURFACE IN STREETS, OMMBgS, OTCHE; A, ALL ER090N ON MASTER DREAD G SWEAKEE, OR PLANHA To BENI utIS EUS� RLV9IRAFEfl By n I�NSTAUSD MTN msTAISfD BY CONTRACTOR MAINTAINED BY D[ySol xG CCXTRAC1gF T Rif [eu xen Br 40 APPRDt£D BY CITY OF FORT CDWMS ON _. City of Fort Collins. Colorado BE CONSTRUCTED UTILITY PLAN APPROVAL ON ONERLOT APPROVED: City Intel Dote BE OVER CHECKED BY'. J SHALL BE USED URING Waty A Wwte.et.r LilRy Date CHECKED BY: THE DETENTION sta„wl Meup rote )ED TO MATCH CHECKED By i PLAN. Pam. A RI..too oat, SHOWN SHALL BE CHECKED BY: 1 ONERLOT GRADING Taff, E,9Wem Date CHECKED BY. WE } p In 9 \iJ\Y I pp 9 grading, tI t oorld ebMn9en by eb9I to ) e' 9 9 ohel 9 t IIIwI Other hernial All COOM « W e..6 Y M9 f thirty oO Al we FOI tic 11 Ill Yale Far OF A y bel an it" 11 woo,. eH� ��a a<1 ..e.1 ea All Ion 9 AN 9"; p� In9RI1M'em6x) ,n mr ced do Face Y aRs ea r d�teee to am" Ireettedleat perforeal their Oriented by Phil rm6.armw >� woY ana mOm 0 F not to cal lRxr rxwee Mt 9 wY. t i NO"gou .M ewnaeeer�nlI be too Ie°vi� w fray, c adm pal the Eep 9 of a 6r any x by Or i why ene be the pyl by nEGENO ADES GN POINT BASIN CR17R;A RUNOFF COEFFICIENT AREA IN ACRES FLOW DIRECTION • • BASIN BOUNDARY ------- EXISTED PIPES PROPOSED INLET AND PIPE FLARED ENO SECTOR M PROPOSED INLET LOCATION EXISTING 5' CONTOUR EXSYNG 1• CONTOUR PROPOSED S CONTOUR PROPOSED 1 CONTOUR -)B(-IB(- SILT FENCE P INLET PROTECTION CONSTRUCTION ENTRANCE BT SEDIMENT TRAP EROSION BALES a 0 R W K � N Na �mOgm� C $x�L�qq� C Orn a 0 (6 m o al C oUAo 4000 �N III To :. pN N II a a CONSTRUCTION SEQUENCE m P 0 0 9TAM RD FM C N 0 PRAT Y1pR5I\A- SECOND YWFN2 itll ttMPtFiFD BV. T1t9 PATE, 'S/ 0/]J H~q by Pw a a ar w will mwwm a° I mm'r'caae,. PormRt ec1: y nW e„ri WROMItln9 a nee ewc" wa for rygrewl by the Clay Ea9Pw. MOM^ PAN, _AN FES a APR V AN .µ AUG Sp OpT MEN DET 719 SHEE' 6 6 OF 11 iO No. 170-03