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HomeMy WebLinkAboutDrainage Reports - 12/21/2017t City offt.'Colhn n ed Plans Approved BY ' Date 1 - U 1' - 17,: October 25, 2017 AN EMPiOYEEANNE'' COMPANY Revised: December 15, 2017 *#&'1BAW tWes Lamarque i 1 __ 1 Enga�eermgjiPlnaurg Turveym0 _ Development Review Engineer ' City of Fort Collins 281 North College Avenue Fort Collins, CO 80524 RE: Drainage Letter — Kappa Kappa Gamma CSU House Expansion DRAINAGE The following letter explains the design and intent of the developed drainage plan for the ' Kappa Kappa Gamma CSU House Expansion. The scope of this project includes expanding the structure of the sorority house, adding additional parking, a water quality detention pond, and storm outlet structures to direct flow into the City storm sewer system. ' With an increase in imperviousness of 6,656 square feet over the existing conditions, this drainage letter provides enough information to approve the drainage design in lieu of a drainage report. The site is located at 729 South Shields Street in the northeast quarter of Section 15, Township 7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. The project area lies on the west side of South Shields Street between West Plum Street and West Laurel Street. The project area ground cover consists entirely of soil type C. The site lies outside of any floodplains as shown in the attached FEMA Firmette. The total area of the site is 1.1 acres with existing and proposed imperviousness of 53% and 67% respectively. According to the.Old Town Master Drainage Report any increase of imperviousness over 5,000 square feet will require onsite detention to account for the increase. The proposed site increases the imperviousness by 6,656 square feet, which will be accounted for in the detention pond as well as the water quality capture volume (WQCV) for the entire area draining to the pond. The undisturbed areas will be left in their historic conditions and not accounted for in the detention pond. The allowable release rates were calculated based on the historic flows and outlined within an email to the City of Fort Collins found in the appendix. The City of Fort Collins' mass balance approach to detention was used to determine the required detention volume. The outlet structure is based on the ponding depths and orifice equation to limit the maximum allowable release rate from the pond. Corporate Headquarters Northern Colorado Rocky Mountains 1950 Ford Street 4007 S Lincoln Avenue, Suite 405 419 Oak Street, PO Box 770152 Golden, Colorado 80401 Loveland, Colorado 80537 Steamboat Springs, Colorado 80477 Ph 303.940.9966 Ph 970,353.7600 Ph 970.879.1825 Fax 303.940.9959 Fax 866.242.9106 Fax 866.242.9106 an,siq bt4votg4IA aniEioQ 14 to ytiO Pagel bevoiqqA li The WQCV and additional deteritioe f6f-ffie site' wiir a trea`•�Sated in a rain garden detention pond on the north edge of the lot with an outlet that will discharge into the public storm sewer system. The WQCV will infiltrate through the filter media to improve water quality. The required flat filter media area was calculated using UD-BMP spreadsheet. The required flat area will be satisfied by providing extra area with a combination of flat and sloped areas at 1:5. The required area is 557 sgft and the provided total area is 818 sgft. The total pond release rate will be controlled by an orifice plate over an outlet pipe. The outlet structure has been designed to release the detained volume at a max outflow of 5.47 cfs. The additional required volume was calculated using a mass balance method, which incorporates the City of Fort Collins' OF curve as inflow and the historic site release rate (5.47 cfs) as a constant outflow. Any volume above the WQCV will overtop the inlet structure and flow into the public storm sewer. Additional volume has been provided above the top of the inlet structure to account for the increase in imperviousness. The emergency overflow route from the pond will follow existing topography to South Shields Street, where it will drain into existing stormwater structures. The WQCV occurs at a ponding depth of 1.67' and the additional volume occurs at a ponding depth of 2.62'. There is a total of 3.5' depth from the pond bottom to the top of wall. The spillway is located on the northeast end of the pond above the top of wall. The runoff generated by the site reaches the detention pond via overland flow, curb and gutter, and storm sewers. The parking lots drain to combination inlets in a sump condition. The capacity of these inlets can pass the 100-yr storm with a maximum of 6 inches of ponding. The inlets flow into 15" PVC pipes at 0.5% slope. These pipes have the capacity to convey the 100-yr storm within the pipes. For complete calculations see the appendix materials. Below is a summary of the drainage basins, detention volumes, and outlet structure. Table 1: Drainage Basin Runoff Summary. DESIGN BASIN TOTAL AREA (ACRES) CZ C�aa PERCENT IMPERVIOUS 2-YR RUNOFF (CFS) 100-YR RUNOFF (CFS) HISTORIC BASINS Hl 0.43 0.87 1.0 90% 0.98 3.90 H2 O.36 0.35 0.4 21% 0.27 1.19 1-13 0.28 0.48 0.6 37% 0.29 1.25 DEVELOPED BASINS Pl 0.46 0.88 1.0 90% 1.17 4.62 P2 0.13 0.95 1.0 96% 0.34 1.25 P3 0.22 0.56 0.7 46% 0.34 1.48 O51 0.04 0.35 0.4 21% 0.04 0.17 052 0.22 0.44 0.6 31% 0.25 1.10 Pagel 3 TOTAL PERCENT 2-YR 100-YR DESIGN BASIN AREA C2 C100 IMPERVIOUS RUNOFF RUNOFF (ACRES) (CFS) (CFS) DETENTION BASINS WQCV (TOTAL SITE) 1.07 0.71 0.9 67% 1.79 7.79 100YR EXISTING 0.56 0.95 1.0 100% 1.54 5.60 (EX TOTAL SITE) 2YR EXISTING 0.51 0.20 0.3 2% 0.29 1.26 (EX TOTAL SITE) 100YR UNDETAINED 0.26 0.43 0.5 30% 0.32 1.39 (OS1+OS2) POND INFLOW 0.81 0.80 1.0 79% 1.87 8.06 (P1+P2+P3) TnhlP g• nAtantinn Ri immary MAX PROV REQ PROV REQ VOL PROV VOL RELEASE RELEASE FILTER FILTER DESIGN BASIN (ACRE -FT) (ACRE -FT) RATE (CFS) RATE (CFS) AREA AREA SOFT SOFT WQCV (TOTAL SITE) 0.019 0.019 NA 0.73 557 818 ADDITIONAL NA NA IMPERVIOUS 0.018 0.018 5.47 4.98 DETENTION ABOVE REQUIRED NA 0.017 NA 1 5.47 NA NA TOTAL 0.037 0.054 MAX: 5.47 1 MAX: 5.47 557 818 Since runoff from proposed improvements is captured by a water quality detention pond and released into the public storm system at the allowable rate, and offsite drainage follows historic patterns, this site complies with City requirements for stormwater criteria. Sincerely, Baseline Engineering Corporation, Noah Nemmers, PE Pagel 4 REFERENCES: 1. Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual, City of Fort Collins, Fort Collins, CO. February 2013. 2. Larimer County Stormwater Design Standards, Larimer County Engineering Department, Fort Collins, CO. June 20, 2005. 3. Urban Storm Drainage Criteria Manual, Volumes 1-2; Urban Drainage and Flood Control District, Denver, CO. January 2016. 4. Urban Storm Drainage Criteria Manual, Volumes 3; Urban Drainage and Flood Control District, Denver, CO. November 2010. E�� ! !` v. .. /\� 141 | g - c / c 2` �§ / r. !) z % #�|§! | d \\! Q § m:' ,() § k §■2 / Iz #! LL j //� , .. l;Its � � e s new *I7 AVrNUE �«A%�a� _, m. \ { \ L /,e § _, coy IS 11AG3nie w < / _ § m� § §_, �� L ( . � )",` § ( ( _• ` .eOttw « j � � 10 59W a S 0 7 3 m 0 c D 'm m 0 0 mm n 0 IW 54Y W 0 Z W 0 W J a a m o E m d a m E ti r w � = y E J m E U 3 m n u m m s002M E 5 mnJmm3 E Hno E YI 'n m mm c m `m m U A C N C L N m m U� O 3i w E O] O w b 0 D w m D m Z U N w ° E m> £ o c c m o a 0.-, g 9 m a m m O mma;� E U W aam �' mN m n cL'Ea m C w C_ w m ¢¢ m l0 O m Q T C O 9 4 0Ewa m u �'i0c(oN' m =rn m rn n m T 1 y c m O w m m .2 c t C E O— w L E m w w o T�°E �' B �35 mw m m ZD. me o2 U m ¢ mmEm m J m o a m E T omD n� 3 t°mona Dm EN m 3 n2$? Q t1Qp E.. o ma.6'`o m m 3i m � n �p J U) w OC w 1� J 7 1] w L$ c L0 m 6 O m m O m K L m¢ U C m w m m 0 y O 5 n 19 L� m Zn E m Ec�N £ Tm mm" rnm iu oJmJ m ¢m2:0 ZmE �L�D pTm oLm0 mE E oL72V�M may£no 9domo mm m ry on°o E2°'U Op O O m LA? mm w E -OuE �FL `_U Mw N� aN �uEw a W N c W U 9 3 L c D a o U ❑ U O ❑ Z W d C A N a K E N ❑ m � V � Q � c 0 13LL g n m n W A - v o 0 `a c o `o Q 'o g r S S u a° ❑ ❑ ❑ o ❑ ❑ a° ❑ ❑ E a W a m U u❑ z W< a m❑ a❑ z < a m ih W \f \/ u O N w N Q m Z 11 Hydrologic Soil Group—Larimer County Area, Colorado Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit— Larimer County Area, Colorado tC0644) Map unit symbol Map unit name Rating Acres in AOI Percent of A01 74 Nunn clay loam, 1 to 3 C 1.1 100.0% percent slopes Totals for Area of Interest 1.1 _ 100.0% Description Hydrologic sail groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, BID, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, BID, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff None Specified L5�Natural Resources Web Soil Survey 4/20/2017 ' Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Larimer County Area, Colorado ITie -break Rule: Higher SODA Natural Resources Web Soil Survey 4/20/2017 Conservation Service National Cooperative Soil Survey Page 4 of 4 (11) Section 4.0 is amended to read as follows: 4.0 Intensity -Duration -Frequency Curves for Rational Method: The one -hour rainfall Intensity -Duration -Frequency tables for use the Rational Method of runoff analysis are provided in Table RA-7 and in Table RA-8. Table RA-7 -- City of Fort Collins ' Rainfall Intensity -Duration -Frequency Table for Use with the Rational Method (5 minutes to 30 minutes) Duration (min) 5 2-Year Intensity (in/hr) 2.85 10-Year Intensity (in/br) 4.87 100-Year Intensity (in/hr) 9.95 6 2.67 4.56 9.31 7 2.52 4.31 8.8 8 2.4 4.1 8.38 9 2.3 3.93 8.03 10 2.21 3.78 7.72 11 2.13 3.63 7.42 12 2.05 3.5 7.16 13 1.98 3.39 6.92 14 1.92 3.29 6.71 15 1.87 3.19 6.52 16 1.81 3.08 6.3 17 1.75 2.99 6.1 18 1.7 2.9 5.92 19 1.65 2.82 5.75 20 1.61 2.74 5.6 21 1.56 2.67 5.46 22 1.53 2.61 5.32 23 1.49 2.55 5.2 24 1.46 2.49 5.09 25 1.43 2.44 4.98 26 1.4 2.39 4.87 27 1.37 2.34 4.78 28 1.34 2.29 4.69 29 1.32 2.25 4.6 30 1.3 2.21 4.52 33 Table RA-8 -- City of Fort Collins Rainfall Intensity -Duration -Frequency Table for Use with the Rational Method (31 minutes to 60 minutes) Duration (min) 31 2-Year Intensity (in/hr) 1.27 10-Year Intensity (in/hr) 2.16 100-Year Intensity (in/hr) 4.42 32 1.24 2.12 4.33 33 1.22 2.08 4.24 34 1.19 2.04 4.16 35 1.17 2.0 4.08 36 1.15 1.96 4.01 37 1.16 1.93 3.93 38 1.11 1.89 3.87 39 1.09 1.86 3.8 40 1.07 1.83 3.74 41 1.05 1.8 3.68 42 1.04 1.77 3.62 43 1.02 1.74 3.56 44 1.01 1.72 3.51 45 0.99 1.69 3.46 46 0.98 1.67 3.41 47 0.96 1.64 3.36 48 0.95 1.62 3.31 49 0.94 1.6 3.27 50 0.92 1.58 3.23 51 0.91 1.56 3.18 52 0.9 1.54 3.14 53 0.89 1.52 3.1 54 0.88 1.5 3.07 55 0.87 1.48 3.03 56 0.86 1.47 2.99 57 0.85 1.45 2.96 58 0.84 1.43 2.92 59 0.83 1.42 2.89 60 0.82 1.4 2.86 34 x.. 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O w n. 1 m t0 J, n N' J: ti 1 H 0 J N N N N O Q 1 c : 3 _ a N N N N d 0000 0c0 0000 pNppp 00 lwlt < d m J N w m ko m LO O 41 00 ? 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(C) = 3.70 3 70 Curb Opening Orifice Coafficierdt (typical value 0.60.0,70) C.(C)= 0.88 000 turns Flow ts (C.1culatenh MINOR MAJOR Clogging CoeRtlent for M uriple Units coer-I 1.00 1.00 Clogging Fads for Multiple Units Cap =1 0.50 0.50 Grab Capacity as a Waif (based on Modified HEC22 Method) MINOR MAJOR Intarcapbon without Clogging Qw= 1.1 3.2 �cfs Interception with Clogging O.. = 0.5 1.5 ch Web Capacity as a Orifice Passed an Modified HELM Method) MINOR MAJOR Interception v41haut Clogging C6 S7 TO Gs Interception win Clogging Web Chan ve ou Mixed Floe Interception wtgtarrt Clopping Interception vbth C legging Resulting Web C eswmss ei condition) -"A USE MAX CAPACITY i SINCE IN SUMP. t 3.5 CFS I W(SW6 CLOGGING j _ _..J U- - O., = Qo = Qary = 2.8 MINOR 2.3 0.1 0.5 3.5 MAJOR 4.4 22 1.6 cfs cb r1s cfs Curs 's Calcuie MINOR MAJOR Clogging Coefficient for Multiple Units Coef= 1.00 1.00 Tg Factor fa M ltiple Unit Clog = 0.17 0.17 Curb Opening as a Weir (based on Modified NECn Method) MINOR MAJOR Interception without Ckggtig Q. 0.1 t.0 ds Interception was Clogging Q. = 0.1 4 c, Curb Operlag es an craft. (batted on Modified HEC22 MMod) MINOR MINOR Interception valort Clopping Q,= 4.5 5.3 cf, Interception with Clogging Curb QPenbcnyas Mixed Flow r-""�"�""" USNAX CAPACITY Qom= 3.8 MINOR 4.4 MAJOR cis Interception wdhocrt Cappnp SEMSUMP: Q. 0.7 2.0 cfs bbrception wet Clapping e.... _.. e.- _..... e_._......__.w _._.__. _._....__. 4.4 CFS ! W/ M CLOGGING 06- € rs_ .. 0.8 .. I., 1.6 cfs Inlet Length L= 3.00 1 3.W eel tani Steel ux FlSpread (based on street geometry fnrn above) T =11 5.0 I 10.0 tare Flo. Depth M Street Craven am. = 0.0 0.0 t, Reed Pedormarlce Reduction (Calculated) MNOR MAJOR i for Grate MxWdh titer = i for Curb Opening Weir Equation ADD GRATE &= ' dOi° iination Inet Pedomonce Reduction Factor for Long Inlets N marim ] RFon„„b= ii RB OPENING Opening PertarReduction Fedor far Lag Web RFa., _ d Inlet Pedoonanca Reduction Faetar for Lag Inlets '=MAX CAPACITY,. 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Thanks, Wes Wes Lamarque <WLAMARQUE@fcgov.com> Wednesday, September 13, 2017 8:38 AM Jordan Piaskowy Noah Nemmers RE: Kappa Kappa Gamma Drainage Calculations From: Jordan Piaskowy rmai Ito: Jorda n. oiaskowy(a)baselinecoro.coml Sent: Wednesday, September 13, 2017 7:01 AM To: Wes Lamarque Cc: Noah Nemmers Subject: RE: Kappa Kappa Gamma Drainage Calculations Wes, Below is the summary of the detention calculations based on our conversation about the Kappa Kappa Gamma Site. Can you please reply to confirm this is in conformance with Fort Collins Criteria? • Max allowable site release rate = existing impervious area 100-yr runoff+ existing pervious area 2-yr runoff • Max allowable pond release rate = Max allowable site release rate— proposed undetained 100-yr runoff • Water quality capture volume = standard equation outlined in the Fort Collins Rational Method Spreadsheet and UDFCD based on area, imperviousness, and drain time. • Additional detention volume triggered by adding impervious area over 5,000 sgft = Utilize the mass balance method within the Fort Collins Rational Method Spreadsheet with the parameters below o Runoff coefficient = 100-yr proposed condition of area draining to the detention pond o Release rate = Max allowable pond release rate as stated above o Area = area draining to the detention pond Thank you for all your help with this. Regards, JORDAN PIASKOWY I Project Engineer, Golden I Baseline Engineering, Planning, & Surveying 11950 Ford Street Golden, CO 80401 1 Phone: 303.940.9966 x209 I Cell: 720.722.01691 Fax: 303.940.99591 www.baselinecorp.com From: Jordan Piaskowy Sent: Tuesday, September 12, 2017 7:28 AM To: 'wlamarque@fcgov.com' Cc: Noah Nemmers Subject: Kappa Kappa Gamma Drainage Calculations Wes, I have gone through the calculations that we talked about and I am still confused on the required detention volume based on the additional impervious area added. I have tried to summarize the calculations below and want to confirm these are in line with your requirements. RELEASE RATE SUMMARY Existing impervious area 100-yr runoff: 5.60 cfs Existing pervious area 2-yr runoff: 1.26 cfs Proposed undetained impervious area 100-yr runoff: 0.78 cfs ' Proposed undetained pervious area 2-yr runoff: 0.38 cfs ' Total allowable site release rate: 5.6+1.26=6.86 cfs Total allowable detention pond release rate: 6.86-0.78-0.38=5.70 cfs POND VOLUME SUMMARY ' WQCV based on disturbed area & proposed imperviousness: 0.019 ac-ft Required additional volume based on increased imperviousness: 0.010 ac-ft • The 2-yr historic runoff rate for the area draining to the pond: 0,47 cfs • Use this rate with the 6,565 sgft of impervious area within the mass balance method spreadsheet. STAGE -STORAGE -OUTFLOW ' Stage of WQCV (and top of inlet): 1.53 ft @ 0.02 cfs Stage of Additional Detention: 2.08 ft @ 5.7 cfs I will give you a call this morning to discuss. ' Thanks, JORDAN PIASKOWY I Project Engineer, Golden I Baseline Engineering, Planning, & Surveying 11950 Ford Street Golden, CO 804011 Phone: 303.940.9966 x209 I Cell: 720.722.01691 Fax: 303.940.9959 1 www.baselinecorp.com z Jordan Piaskowy t From: Sent: To: Cc: Subject: HiJordan, All looks good. Thanks, Wes Wes Lamarque <WLAMARQUE@fcgov.com> Monday, October 23, 2017 8:45 AM Jordan Piaskowy Noah Nemmers RE: Kappa Kappa Gamma Drainage From: Jordan Piaskowy rmai Ito: Jorda n. oiaskowyCcbbaselinecoro.comj Sent: Thursday, October 19, 2017 4:32 PM To: Wes Lamarque Cc: Noah Nemmers Subject: Kappa Kappa Gamma Drainage Wes, Thank you for taking the time to talk through the comments with me on Tuesday. It seems like we are close to an approved design. I have summarized our conversation below. Please confirm that you agree with it. Comment Number: 2 • The detail will be updated with correct depths and added to the report. Comment Number: 3 • Resolved as -is. • Regular maintain will utilize the boulder step and major maintenance with use a temporary ramp for access. Comment Number: 6 • Plastic pipes will be utilized on site. • 15" RCP pipe will be used for ROW connection. Comment Number: 9 • Drainage easement will be added around the walls of the rain garden. • Easement will be shown in the plat. Comment Number: 10 • Bio-retention calculations will be added to the report. • The filter area requirement will be met by including the entire rain garden footprint with filter media. • There will be a 6'x26' flat area and the rest will slope 1:5 to the retaining wall bottom. Comment Number: 12 • Outlet structure will be revised. • Remove the underdrain orifice (water quality drain time does not apply). • Top of the inlet structure will match WQCV. • Outlet pipe with restrictor plate will restrict flow to calculated max 100yr outflow rate. Thanks, JORDAN PIASKOWY I Project Engineer, Golden I Baseline Engineering, Planning, & Surveying 11950 Ford Street Golden, CO 80401 1 Phone: 303.940.9966 x209 I Cell: 720.722.0169 1 Fax: 303.940.9959 1 www.baselinecorp.com N v L U U1 C E U +' N C L � N "6 3 Cf v 3 0 to 7 C i/ ' 3 O a a m V � N > ` v �' OU C cc N C O N L V L CD W CL U C CL Q II II 11 Cu Cf 3 ai L Q C v E 3 N fo L O N L 3 v Y (� N C eVV� Cr N y .r � 11 N `i L C� V u CN m C 3 fo Q :;o' v a" r r r r r W tD 00 00 V V M M to to A A W W N N O to O tOit O to O to O W O to O to O to O to O to O to O p` r r r N N N N N N N N N N W W W W A A A In 01 V lD 00 00 00 t0 O O r N 1v w A to J w O N A V O In tD m In J w O A Oo A O O w r t0 W W W r M w w to A W r. V r N A 0) 1.... 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V V V V V V V V J V V V V V V V V J V V V V V J W W W W W W N N N N N N r r r r r r kO 00 0) A W N 'C t0 V M A N r to J (n A N r tD 00 cn A W r 00N to w N (n W J r A 00 r W 00 N M tD W M O A V r A A O M N 00 A w A A W O N m r N 0 V W w W tO V w M r In J A W W W N to r r 0 m t0 N W w V Ol to A W N r : 'M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 » O O O O O O O O O O O O O O O O O O O O O O O O w. O_'. C' 9' m Ol In N (n A A A W W W N N N r r I- r 0 0 0 6 0 0 Q... to N w to N w to N w w N w m N w m W O J In N O W In r J W O J A r GO to W r W V M W A N O M A re _ :.: CD ,..r.,..:a:' rD DETENTION POND STAGE -STORAGE -OUTFLOW SUMMARY Detention Basin Outlet Structure Design` UD-Detention, Version 3.07 (February 2017) Summary Stage -Area -Volume -Discharge Relationships The user can create a summary S-A-V-D by entering the desired stage increments and the remainder of the table will populate automatically. The user should graphically compare the summary S-A-V-D table to the full S-A-V-D table in the chart to confirm it captures all key transition points. Stage Stomp:` De ripnon glage [at Area Ift') Area r [acres1 Volume {ft-31 volu ' me [ac Rl outflow [crsl POND BOTTOM 0.00 89 0.002 0 0.000 0.00 1.00 484 0.011 284 0.007 0.64 WQCV 1.67 818 0.019 927 0.019 0.73 2.00 818 0.019 1,097 0.025 4.60 ADDITIONAL REQUIRED VOL 2.62 818 0.019 1,612 0.037 4.98 3,00 818 0.019 1,923 0.044 5.20 OVERFLOW 3.50 818 0.019 2,332 0.054 5.47 Tnhip 9• rletantinn Summary -or best results, include the >tages of all grade slope :hanges (e.g. ISV and Floor) From the S-A-V table on iheet'Basin'. 41so include the inverts of all cutlets (e.g. vertical orifice, werflow grate, and spillway, Nhere applicable). MAX PROV REQ PROV REQ VOL PROV VOL RELEASE RELEASE FILTER FILTER DESIGN BASIN (ACRE -FT) (ACRE -FT) RATE (CFS) RATE (CFS) AREA AREA (SOFT) (SOFT) WQCV (TOTAL SITE) 0.019 0.019 NA 0.73 557 818 ADDITIONAL NA NA IMPERVIOUS 0.018 0.018 5.47 4.98 DETENTION ABOVE REQUIRED NA 0.017 NA 5.47 NA NA TOTAL 0.037 0.054 MAX: 5.47 MAX: 5.47 557 818 WEIR CONTROLLED Q = CacwL Hl.s Equation 12-20 Where: Q = discharge (cfs) Cac"T= broad -crested weir coefficient (rhis ranges from 2.6 to 3.0. A value of 3.0 is often used in practice.) See Hydraulic Engineering Circular No. 22 for additional information. L = broad -crested weir length (ft) H = head above weir crest (ft) ORIFICE CONTROLLED Q = C^-4^(2RH.)'5 Equation 12-19 Where: Q = the orifice flow rate through a given orifice (cfs) C, = discharge coefficient (0.60 recommended for square -edge orifices) A. = area of orifice (ft) H. = effective head on each orifice opening (fo g = gravitational acceleration constant (322 fusee') Design Procedure Form: Rain Garden (RG) 1 11 Designer: JTP Company: BASELINE ENGINEERING Date: October 25, 2017 Project: KAPPA KAPPA GAMMA SORORITY EXPANSION Location: FORTCOLLINS 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, (100% it all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = IJI00) C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time (WQCV= 0.8' (0.91• i3- 1.19' �+ 0.78' i) 0) Contributing Watershed Area (including rain garden area) E) Water Quality Capture Volume (WQCV) Design Volume Vol = (WQCV 1 12)' Area F) For Watersheds Outside of the Denver Region, Depth of Average Runoff Producing Stone G) For Watersheds Outside of the Denver Region, Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume (Only it a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) 8) Rain Garden Side Slopes (Z = 4 min., hor¢. disc per unit vertical) (Use'0' drain garden has vertical walls) C) Mimimum Flat Surface Area D) Actual Flat Surface Area I, = 79.0 % I i?'''0790 WQCV watershed inches Area = 35,284 sq it Vwocv = cu it de = in Vwacv or>ER "'"� 3'': cu it Vwacvu R= cult Dwocv = 12 in Z= 0.00 ft!ft A. =,',' k 557 s-" sq ft A� = 818 sq ft C03176-UD-BMP_v3.06.xlsm, RG 10/25/2017, 3:11 PM No Text 62 com WAIL / BANKS 6' (11P.) W 122 GC EACH WAY r 4l Aq IiGfiN:Giiiiiiia IMMMMMMMWMMMMm IEMMOMENOMENEloommosomommoso lemons NONE 1......1....... mommoomm lo.0000.c. 12' PVC W11£T PIPE `SAFETY GRATE MITI Bill kB OFAR BLOWER BARS CUTLET AlDlnau M+r.r STFLAUTLEE PLAN MSL - wna2 BOLT OR LOCK RAW SM4EL Hill LL� —4' vNOLY NSf1_ 51 15r 1.6T e' POND WTTOM •. �r a 1f YN }GREIIIgI aw MEGA M K N �W PEA 01AEL n� L K IN mDT N0.4 AOOBAE 4' (YIN.j •ITV 0 Smilai m PLD RE RIOAO SECTION A -A 1411.:a:•Wa1SQ'laf0 SPILLWAY PROVIDED CONTINUOUS NEOPRENE SANE[ BETWEEN MIME PLATE N!D STRDCNRE (M) AIDHICNAL VOLUME ROW RESTRICTGR PUT. HE DETAIL BELOW 12' PD Dul PIPE A 0.25• (T) M11IME ROW RLSTd m 1i. ROAM CONTINUOUS NEOPRENE GASKET MATERIAL EEINEN THE DIRECT PLATE AND OokO 2 BOLT Ile MIN PLACE TO CONCRETE IY MAX ON WREN. DY1t�J1tffi9ds I. ALL Ski AMID GRATES SHAH O ABLEMCAUNTED AC ESNG STAINLESS STIFF HARDWARE AND PROVIDED MM HAFETY AND LOCKABLE OR BOLTAEACCESS PANELS ALUMINUM 2. GALVANIZED ZED AN SHALL EHOT PWSTAINLESS STEEL 0AFTER OR STEEL STEEL CRAZES 91,N1 BE HOT OIP GALVANIZED AND HAy BE HE PONDER COATED ATHE GALVANIZING. d. SAFETY CMAN SHALL BE DESIGNED SUCH THAT WE IIAGCNAL DINEN9M OF EACH OPENING IS SNALLffl AL D ME DIAMETER TRASH DE THE SHA L PIPE. 4 DOWS EAL DESIGN OF CRPSH RACKS SHALL BE BASES fM FULL HIDRGSTABC HEAD MIN ZERO IEIL DOM151HEAN OF ME RACK. liters1 WARNING THIS AREA IS A STORMWATER FACILITY AND IS SUBJECT TO PERIODIC FLOODING WATER WALITY § DETENTION POND OU71ET STRUCTURE vI a4 WANNNG SIGN TO BE FREE STMNW SIGN ON A ♦'14' MOW POST. ALL STORMWAMR FAO -TES SHAM HAYS A MINIMIM OF TWD SIGNS MM RED LETTERS ON A WHIM BACKGROUND. POSTED IDONTMNG THE DETENTION POND AREA. ME SIG15 SIIALL SHE AS SHOWN HEREDN. / 3 STORNWATER MANAGEMENT FACILITY SIGNAGE C4 C14 slowr a m W OF FORT COLLINS E IETEHTON SAHO MEDIA SPECIFICATION z Ln 11-GENERAL Car A Bbalenlion SSM Mean LBSMI shall Ee umknnly forms unrvmpatlea. free of stories_ PPPPPPP. — alumps rwM or mrs Samoa buy S lager than your Inches No dMr materials or substances small pre mina «eomMd wflnn the harp eneon area anal may 5e narmlW to Apt — g h or prove a unstable to Has Fell s hanalm and membranes W W BGM& llb frmdpMntus mammal but nonalf rmmrve spoons. or Woodsup — Sir �— G. FUlly mpM BSM SNaIl betaslW pwr to lrrstallafprr anamMlne ldlwiy uileria: I. Nor ales: llun 3o to car 2. but of 515wwtegEll . SnN pH fall e of the acceplabk range, n may mo]Rreantl w If" (to rebel dead, sulfate now; suXw (to bwcl. Than lime uimn suborn must Ce mhos undermrt info lire SSM pace to use In me blw&eabn radial. 3. Calm E,&ange CardauteIgreater Ilan10 Phn 4. pn MS (Phosphate . PaNd mceetl erM yin mini 5. 9M I) fail to mono um gmmme s II forreplec E al the Cmnaclas expense D. BSM Strait royal fully mixed in a drum r. Sru ...no of pies will Out ther allowed Mixing of Me BSM to a M1omrymc enus ons9 lenry Shall ne done to the sallslaceon of theOwner Selq 1. BSM snaA cons¢)of W70% sarld by vdwre meeting ASTM C-33Saudi Peaks 1_ BSM Tall conssl of 590% stersol order by volume 2 Shaded peoom shall be loosely pxsee approximate bulk rurally OF 1100 IWCV. 3. SMMaed paper shall pan sisl of loose lest Bakernot shredded bumble CNs, and Nail Ca annually add mechamrally mired 10 prevent clumping Tlgsml 1. BSM anon ooni o15-1o%lc lby Voll 2 best mall be aaaanatl as so" loans fumy sand or loon M USDA textural manors Evill less than material shall not la 3. Onsre.lee 1 lceused tas opol preferably a. Tealur. analysis hall be renames on rf subsoll mxayly else source. plot baseball andy other material m she mix Topsvn snau nt Tree of subsal, aeons, xeetls Ivmgn manse and any ee ,moe f health 5ma baseorrangops 5End marell soared Footwear $5h55% 6Contractor Wait arylam Fail memathese cell Leal Comers SSM Shop crn59 o11020%last co by 2. Leal mmpasr shall cooked of Cass 1 Organic leaf compared consfustrah of Stand sal much raun rg falls bang rel degradation and mnslama 0n or planrde(vea materials under draled conannns designed to promote Seldom Beclanton on SAND MEDIA SPECIFICATION March it. nil B. The mall shall the Wan compostedlr viable weed seeds and contain andeal old g rally humus nature console or smug smash or vegeumon well no mabrbls lose sopal carts 4- Cancer Voill Ee amvmd by a U, of US Controlling Consul warl of Testing Assurance (STA lbninef to aMtm appvs so by the Ownpact del," of SSMSd,M protestSaStrait We fu5. CarpOsl medal than also least he fdawingclens ecaradial. 100 rnt of the lenal shall pass Prmgh a 1)21nr11 screen d PH Or the malenal Shall I amounted 60 and Ba c. Mdmure content shall see ancestor 35 and 50 pscam d. All greater than 00 percent tonal indictor e+Ve W all g tU or gmmmII rw190r 801E80.) e. Sol ... dkioplessW as Carton to domed based 112 1. Maturity Indicator e.prem as AmmomaWNhmbN Reoo Ea g. Minimum organic mans Shall SAY 40 Bernard dry wri WSIS IN Solusb un content rsall Bee no greats than 53CU parts cw mllllm Or 0.5 mmpsoll I. Phosal0ms content shall Ce no greater than 325"MWmibn 1. Heavy morale Dmpe)mtermt trues O SBebpwmim k. Chemical contaminants meet a exmea US EPA Cases A Na W 40 CFR 503. u. Tables 1 A 31tvels I. Pwsrytns meet or exwaa US EPA Class A tl»]ve. 40 CFR Call base Rr3-EXECUTION! A Oostl 1, Relo m pcpct rya sfa exu ttl �remene. 8. RSR tMMn 1. B malenal shall as spread evenly m MmalUl eyes. 2. Thickness of acres material in each layer shall not exceed CiMw. 3. Canpabm Of BSM material l is prealuirll. er sparked MOW Minimum 30-mil Stmtture HOPE ImP Wv onellq cepin MembranIReaukee fwBUIIJIng Pr 1W) InImI2-ThckL er tention Sato Meatsrebntlbn 712'ftndlN Saba peCllcatlon Iromort Conlin) 6-Thick layer MMMImm vel DlaphngmNo.4 C9OT Aggro ,!IBM 8-nick layer Of CMPo`o.4 AgPVc a'verltreb0 Plm Pass (optional Cepenaing on Underlying Son Contributes) BIORETENTION / BIOSINALE CROSS SECTION ( [At*" 4 FPWP MIWW STORMWATER APPAD.m: DETAIL m CONSTRUCn01N DETAILS drnlh Ti —553 D1 / TYPICAL RAIN GARDEN SECTIONS G C14 Its l�� l�71 ( r