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HomeMy WebLinkAboutDrainage Reports - 07/14/2016I ' INORTHERN ENGINEERING 1 1 1 1 1 1 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 January 25, 2016 City of Fort Collins Ap roved Plans Approved by. Date./4/%OtcO RE: Drainage Memorandum Brookfield Second Replat, Lots 1-12, Tract E and a portion of Tract D Fort Collins, Colorado Project Number: 374-020 Dear Staff: Northern Engineering Services is pleased to submit this Drainage Memorandum for Brookfield for your review. Brookfield Second Replat is located within Lots 1-12, Tract E and a portion of Tract D of the Plat of Brookfield. The Brookfield project is a proposed multi -family residential site. The site is located in the Northeast Quarter of Section 4, Township 6 North, Range 68 West of the 61h Principal Median, City of Fort Collins, Larimer County, Colorado. The site is bounded on the north, east, and west by undeveloped area. The site is bounded on the south by Brookfield Phase 1, a multi -family site. Fossil Creek Reservoir Inlet Ditch (FCRID) flows north-west to south and is located east of the site outside of the project boundary. The proposed 10' pedestrian trail along the east side of the site is more than 50' west from the FCRID water surface elevation and minimal grading is proposed within this area as shown on the Drainage Exhibit. Southeast of the Site is Detention Pond A constructed as part of Brookfield Phase 1 development that currently detains flows from Brookfield development Phase 1. Detention Pond A was designed for future development of Brookfield including this site. The site falls within the East Harmony Portion of McClellands Creek Master Drainage Basin. This Drainage Memorandum has been prepared in compliance with technical criteria set forth in the City of Fort Collins Storm Drainage Design Criteria, Urban Drainage and Flood Control District Criteria Manual (UDFCDCM) and City of Fort Collins Amendments to the UDFCDCM. The Brookfield project consists of approximately 6 acres. The development will consist of 12 multi -family buildings with approximately 68 units. The buildings will be two story with the possibility of basements. Parking will be provided by on street parking, parking stalls off the alleys, attached garages, and detached garages. The streets within the multi -family tracts will 1 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com F L n `j NORTHERN ENGINEERING be private and will be maintained.privately. Public streets bound the tract. ' The proposed site has been a part of many different drainage plans and studies in the past. The most recent drainage plan, Final Drainage Report for Brookfield by TST dated ' December 14, 2001 covers the entire Brookfield development including already constructed phases, the proposed site, and future development. The TST drainage report for Brookfield references two previously completed Drainage Reports that are a part of the McClellands ' Drainage Basin: Final Drainage Report for Willow Brook by TST, Inc. Consulting Engineers, dated October, 2000 and East Harmony Portion of McClellands Creek Master Drainage Plan Update by ICON Engineering, Inc. dated August, 1999. The proposed site closely matches the original ' proposed development as part of the TST Brookfield Utility Plans and TST Brookfield Drainage Report and is in compliance with the original TST Brookfield Drainage Report. The calculations presented in the original report for all of Brookfield including proposed and future ' developments has an Imperviousness of 73% and the area corresponding to the current proposed Site has an Imperviousness of 71%. The current proposed Site has an Imperviousness ' of 53%. A Comparison Table with drainage basins and imperviousness values for the original Brookfield plan and the current Site is included herein. Drainage Basins are named to match the original Basin names of the TST Drainage Report for ease of comparison. Several ' constraints have been identified from the original report including the maximum runoff allowable into existing inlets and drainageways. Specifically, the Brookfield Drainage Plan divided the site into two basins. The interior of the site drains to an existing storm sewer ' system. The north and east perimeter areas drain offsite to the existing FCRID. This Drainage Plan incorporated the 100-yr maximum release rate from the Brookfield site as 0.5 cfs per acre. The site currently sheet flow from west to east with an average slope of 0.5-1.0%. ' Currently most of the Site is discharged into the FCRID. The southern portion of the sites flows into an existing curb inlet on Precision Drive and into the storm sewer system that flows into Pond A. The existing land onsite is currently undeveloped and consists of loose soils with no vegetation. Most of the Brookfield site (constructed and future phases) is graded to Detention Pond ' A. This water quality detention pond was sized based on SDDC and Urban Drainage criteria and has a release rate of 0.5 cfs/ac. The pond was constructed with an orifice plate with multiple orifices to provide for an extended drainage time. The water quality volume was based on a 2- ' yr storm, with the 100-yr storm overtopping the control structure and entering the discharge pipe. The pond was provided with an orifice plate on the discharge pipe to control the 100-yr discharge from the pond. If the pond were to overtop, it will spill in a historic eastward ' direction and into the FCRID. No structures will be inundated if overtopping occurs. The required volume of the detention pond is 9.01 ac-ft. ' Offsite sheet flow from the west in Drainage Basin D-5/9 is proposed to be intercepted by a drainage swale and into a storm sewer system that goes to Pond A. Offsite flows north of Le Fever Drive are channelized in a grass swale that flows into the FCRID. Offsite flows from the ' eastern portion of the site include the bank above the FCRID, proposed 10' wide trail, retaining 2 ' 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com ' I NORTHERN ENGINEERING ' walls and graded slopes. As this area will be vegetated and closely match undeveloped conditions it is proposed to release undetained. This undetained release will not be accounted for in the design of the detention pond since it will be at historic rates. All developed subbasins ' are proposed to discharge from the site at a release rate of 0.5 cfs per acre as dictated by the master plan after passing through the Pond A. The overall stormwater management strategy employed with the Brookfield Second Replat is to closely match the original design while incorporating current LID practices to minimize adverse impacts of urbanization on receiving waters. Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peaks, volumes, ' and pollutant loads as the site is developed from the current use by implementing multiple Low Impact Development (LID) strategies including: N-4 Providing permeable paver areas with underground detention area to increase ' time of concentration promote infiltration and provide water quality. N2 Providing a Drywell to promote infiltration and water quality for a portion of the ' site. W Providing a Rain Garden and Bio Swale with Soft Bottom to slowly release the flood control volume in an area and removes pollutants by treatment processes of t sedimentation, filtering, adsorption, evapotranspiration and biological uptake of constituents. N-9 A Snout and settling basin within an area inlet for water treatment prior to flows ' entering the subsurface infiltration galleries and storm systems. The overall stormwater management strategy employed with the Brookfield Second ' Replat is in compliance with the following standards: N9 City of Fort Collins' Stormwater Criteria Manual. NN Final Drainage Report for Brookfield by TST ' N-9 There are no regulatory floodplains associated with the development. N9 The drainage plan and stormwater management measures proposed with the development are compliant with all applicable State and Federal regulations governing stormwater discharge. Included herein are Rain Garden calculations showing compliance with Colorado Statute §37-92-602 (8). The Rain Garden meets the criteria listed in the statute including continuously releasing and ' infiltrating at least 97% of all runoff from a rainfall event that is less than or equal to a 5-year storm within 72 hours and releasing and infiltrating at least 99% of the runoff from a rainfall event greater than a 5-year storm within 120 hours. N9 The site achieves the requirements set forth by the City of Fort Collins for Low Impact Development (LID) by providing 25.8% of total paved areas as permeable pavers and providing 59.3% of total impervious areas as being treated through an ' LID treatment. A LID Conformance Report is attached to this Memo that includes LID sizing and exhibit. 1 3 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com I J 1 INORTHERN ENGINEERING The drainage design proposed with this project will effectively comply with previous studies and will limit any potential damage or erosion associated with its stormwater runoff. Inlets located in the alleys are designed to collect the 100-year flows; capacity calculations are included herein. The proposed curb inlet (Design Point D3A) located on Northern Lights Drive is designed to convey the majority of the 2-year flow with 0.1cfs by-pass to the existing downstream curb inlet located on Precision Drive (Design Point 43). Design Point D3A matches the TST Drainage Report, Design Point 55. The TST Drainage Report had a runoff of 2.32 cfs for the 2-year flow that was proposed to runoff to the curb inlet on Precision Drive (Design Point 43); therefore a reduction of 2.22 cfs is conveyed to the existing inlet on Precision Drive. All existing downstream drainage facilitie$ are expected to not be impacted negatively by this development The drainage design is anticipated to be very conservative. We have omitted any runoff reduction that will manifest due to infiltration from drywells and pervious pavement. This is currently unable to be calculated with available soils data. If you have any questions, please feel free to contact me at your earliest convenience. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Amber P Project I ATTACHMENTS: ATTACHMENT A ATTACHMENT B ATTACHMENT C ' ATTACHMENT D ATTACHMENT E ATTACHMENT F Hydrologic Computations and Drainage Exhibit Inlet Calculations Storm Sewer Calculations (Hydraflow) Imperviousness Comparison Table Low Impact Development Conformance Report Rain Garden — Compliance with Colorado Statute §37-92-602 (8) 4 1 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 www.northernengineering.com ATTACHMENT A HYDRAULIC COMPUTATIONS AND DRAINAGE EXHIBIT I 1 1 n ' NorthernEngineering.coin // 970:221.41SB I m 1 I T Z SE 9 mn n� m M ae � ae I M o m mmn m m mm E- n b b b a 0 M m b M b b n m m m N b U o N N C Y IE qp d mbm O mmmOnO-O O O O°m m n c p Y o n o m m 0l o o b m m € 8U •�O •-+ G 0 0 0 0 0 G 000 0 •�•-• 0 .+O 00 N n E 0 O d m q O O C V � !� U �•.« d N m O b a n N N m•-• O i (1 n yy N n O O O g g mb 0 0 m 0 1� nnb 0 0 0 0 N Nnmm�Onm 0 O O O O O O o m 0 o mn C o o U E u CS p 8 ci o V 1C C m O m OnN n nm m•-•<m N NI\ Of m O 3 oo O o o o0 o 0 .6-q oo0000 nm 0 inn 0 o0 ai u a c T m� +-aab m.+o�.-•urn 'n bmm.�o.+n -. n'� mm X m 00 0 mmmb 0000 mmnNmabNb^mm a•-•o 0 0000a a 000 O? 0 mo o0 9 o N n m n � n a n F 0 N d � u o y _ � v m 'd Z 0DR- a ae of o° o 0 0° o° " 0 on O O �:a.-•mmpp N N ^• N .+ o-. 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PAWf � .FSsnNnU3; 1 � I�11 1 I 1 Itl \ I 1t FNMOBFO81MM9FMEN \I Ilk lSIIS\II PERI.EMLEPAVEFtS ill �I Iriv II �— ,� z Bs LuW I'. \l \ I T' { puMAaE aesM xumLE I ,— 1N m Z y I I: � I I I' - oesEN IYNXI q � E OZ NOTES: 1. NE SM. TYPE AND 1-0 MON OF ALL KNOWN UNDERGRaxO UnUIES I \ I5 ft \j M(, ARE APMOMIMATE WHEN SHOWN ON THESE DBAWNOS IT SHA BE ME REBPONMI OF THE CONTBACTM TO MMFY TIE EXISTENCE of uL MDERGRWNO Mu`FES IN ME AREA OF NE WORK. BEFORE a I 5G{ COMMENCING NEW CONSTINOrM, TIE CMIRACTgf SHALL BE RESPOI FOR LOCATING ALL UNDERMWND MUTES AND BHALL BE RESPPVS BI£ TOMFMML UNNNOWH UNOERpfg1NO UnUTTS { Ap I' I 3. REFER TO n1E dIMNA4£ MEMMMMM BROq(fTE-D BECOME REPI.AT BY NMTHEf l ENSMEEMNQ, OAMD A WST A "IS FM ADOMOM 3fy \ I\ INFIXMATIXL 9i Y8 A a v .unarm ,wr[x:w r ]. HABITAT BUFPER 1 ME IN 10 BE MMNTNNED E A EWW USES W 4£ SECnM ].A.1 O TINEIAFE IISE CODE FOR ALLDHBIE USESW1HIM _ THE DUFFER IME HABITAT MU E IB BETWEDI T LOT W `I .WO EASTERN EDGE OF PFOESMAN VI EF E. 2 I O \\\ F LU LU \ Z X O uj ----- LU Lu Ln 0 Q POND FOR DRAINAGE REVIEW ONLY Lu Z_ \, \ NOT FOR CONSTRUCTION LL Q Y 0 City of Fort Collins, ColorBA,, UTILITY PLAN APPROVAL. PPRD\ED Ham— Tr CHECKED BY: m WeleY b Weetehnle� JIHI, Del• CHECKED BY: CHECKED en �— NECKED en D R 1 NEp m Br. _ T,�i D.t. 26 0I 18 ATTACHMENT B INLET CALCULATIONS ' NorthernEngineering.com // 970:221.4158 INLET IN A SUMP OR SAG LOCATION Project = Brookfield Second Replat - Project no. 374-020 Inlet ID = Dplgn Point 47 - Pri"te Alley with Type 13 Inlet at SUMP ,f—Lo (C)-4' H-Curb H-Van Wo Wp W Lo (G) �n Information Itnsu0 of Inlet Inet Type Depression tadditronal to continuous giver deprssion'a'from'O-A1oW) a. nr of Unit Inaba (Gmte or Curd Opening) No r Depth at FbvNrw (outside of bcal depression) Fbw Depth I information Ih of a Unit Grate L. (G) 101 a UM Grate W. Opening Ratio for a Grab (typical values 0.15-0.90) A. peg Factor for a Strata Greta (typical iakn 0.50 - 0,70) C. (G) i Weir Coefficient (typical value 2,15 - 3.60) C,. (G) e Orifice Coefficient (typical valre 0.60 - 0.60) C. (G) OW -I a atfumtafbn th of a Unit Curb Opening L. (C) Y of Vertical Cub Opened In Inctns K. 1 of Cub Orifice THpat b Inches tfwy t of Tleoat (see USDCM Fauna ST-5) Theo Width for Depression Pan (yplmlly the puller width of 2 fast) Ws prig Factor for a $.rate Curo Opening (typical valor 0.10) G (C) Opening Weir Coefficient (yp cal value 2.3-3.6) G. (C) Opening Orifice Coefficient (typical vabe DAO - 0 70) C. (C) at Inlet Interception Capacity (assumes clogged condition) Q. Capacity IS GOOD for Mnor and Ma1a Storms (>O PEAK Orsvaaeoueo MINOR MAJOR CDOTIDeINer 13 Valley Grab 2.00 2 Or 1 I 3.5 SA runo a ino 3.D0 1.73 0.43 0.50 0.50 3.30 0.60 NIA NIA WA NIA NIA NIA NIA NIA WA MINOR sane eat eet eel tches ties agrees eat 374-M - Alley - Design Point 47 - Type 13-Single - UD Inlet 3.1.Idsm, Inlet In Sump &2712015, 3:04 PM INLET IN A SUMP OR SAG LOCATION Projects S ooktield Second Replat - Project no. 37"20 Inlet ID = Maximum Flow - Design Point 56 - Private Alley with Type 131n1e1-Double at Sump ,r Lo (C)--q- H-Curb H-V en Wo W WP L. (G) lesion Inlorrnation (input) ype of Inlet ocoI Depression (additional to continuous gutter depression'sfrom'O-AboW) umoer of Uric Inserts (Grate or Curb Oper ing) Vater Depth at Flowee (outside of boat depression) ,one mfomnattlwn ergth of a Unit Greta VMh of a Unit Grate ,me Opening Raw for a Grata (lypral values 0.15-080) :logging Factor for a Single Grate (typcal value 0.50 - 0.70) ;ale Weir Coefficient (typical value 2,15-3.60) ;rate ordiceCoefficient (ty WYews 0.60-0.60) :we Opening hfomueon englh of a Unit Cum Opening g legh of vertical am opening In Intones legh of Curb Chixa Thoat in Incites ,ngle of Thoa1(sate USOCM Figure ST-5) side Width for Deprmsion Pen tlygcally the gutter width of 2 feet) :logging Factor for a Single Curb Opening (typical value 0.10) :urb Opening Weir Coefficient t (typical value 2.3-3 6) ::ro Opening Orifice Coefficient (typical vats O BO - 0.70) 'opal Inlet Interception Capacity (assumes clogged condition) Art Capachy IS GOOD for honor and Major Stomra (> PEAK) I INet Type 8. No Flow Dep h L,(G)' W. hoe' Ci(G): Ce (G): Hue.' Thai We: Cr(C)' C.(C): C.(C): ore° ae:zxee' MINOR MAJOR CDOT/Demer 13 VeI)ey Grate 2.00 2 u0 notes 2 3.5 9..0 notes MINOR MAJOR 3.00 feel 1.73 eM 0.43 0.50 0.50 3.30 0.60 N/A N/A WA N/A N/A N/A N/A N/A N/A sat ches ohes egraes ,at 374-020 - Ailey - Design Point 56 - LID Inlet 3.1.4sm, Inlet In Sump 8127/2015, 2:27 PM INLET ON A CONTINUOUS GRADE Project: Brookfield Second Replat - Project no. 374-020 Inlet ID: Northern Lights Drive (Local Street) with Combination Inlet - Design Point D3A i-U0 (C)-T H-Curb N-Ve4 Wo w MINOR MAJOR Type of net Type= CDOT/Damer 13 Combaetion Local Depression (additional to wnllnmus gutter depmssbn'a' fmm'O-AIIoW) arorµ= 2.0 inches Total Number of Unts in lie )net (Grate or Curti Opawng) No .= 1 Length of a Single Unit Inel(Grete ar Curb Operirg) La= 3.00 art'. ft itlth of a UNt Grate (cannot W greater Man W from O-Allow) W. = 2.00 J, ft Clogging Parlor for a Single UM Grate (typical min. value = 0.5) CrG = 0.50 0.50 CloaoiroFedorfore Simle Unit Curb Ooenro fhrr Mal min.value=0.1) C.C= 0.10 0.10 Inlet Intemeption Capacity Inlet Larty-0ver Flow (flow bypassing inlet) re Percentage = O,IQ = 374-020 - Design Point D3A- Northern Lights - UD Inlet 3. t.alsm. Inlet On Grade 8/2712015. 2:49 PM ATTACHMENT C STORM SEWER CALCULATIONS (HYDRAFLOW) NorthernEngineering.com !/-970.221.41S8 (D Q W Z J CC O � U) S C' W O Q W z N Q Q J o W W N z z O J J N U z Ir c O O C7 0 W v () (n ED E E z � N r N N � � O Q W n N z Q o J CV W Q z O W z_ CE (n J O m � cc O a I— r v� O E W C OI N N 0 O O N r v LL ri u Q a '0 Q) 0 E 0 O 1U) 0 N O 7 w 0 d i 1 i 1 1 i i i 1 8 0 0 8 8 8 N N r C4 m Go O v m a m r GOD v v m v 0 m t^0 "'9e9V'13'nul VVIDO6V73'PWO o WWI 991130+9 Big m 0 h o r _ - o ul e¢'"QV'l3 'Aul ;^0 ze'Be" •13 'Awl o 991e9Y '13 ' P W O 9 :uI - VEY'a 1+Y 146 d 0 a Q w u1 C6'66eV'13 'Aul o Z mOee'eeeY'l3'Aul a�•eeeY'13'awo � 9 :ul • LWOW M D_ W 06'969Y l3 'AuI 'Au! e ~ IMC 01'ZeeY'13 co VPteeV'13'PWO Y ul - el'6L+z ale N O ' N O N r ul M O *13 'eul � ;n0 6V10"'13 'Aul w 1,04111013 13 • PWO O c :ui • seo'ao+L vie J O = ul as'OeeY'13 'Aul 3n0 ZB'Oeat'13 'Aul VZ'e69V ' 13 ' PWO aa'ao+o one 1, o 1 _ 04 V Y Y Y O f _d w 1 i 0 IL �Cl) E �-W co O S S O O S pp 0�p) S eppp V LSO 9L' Ee8V ' 13 'Au I eo'9eao'13'PWo e .u'1- EVL'ZC+Z M N N 8 f N Ln UI U'6ee4'13 'Auk ;no ZB'Leetr'13 'AW o ZL'2e2r'13'PWV N i:ul 91i'LV+L148 LU J L N � � O N UI BB' Lei1r '13 'AU1 3n0 QL' Left 'I3 'Aui 9i'950V'13'Pw© 8 w I L :ul - B0Z'19+0 e48 N J I ul Cr Lein '13 'AU1 #M0 ZB'0eei'13 'Auj 02'6ee0'13'PUJD oa'Oc+a ale 0 1 8 8 8Of 8 8 8 W I 1 1 1 I d 0 IL 1CD cn E '-W CD O O S o 0 8 0 0 o m rn cm v o v a a -- - e - - - - v in0 f9'9681'13 'Aul 99'969i'l3'PWO ,n L:ll 99s'91+s 149 0 C4 N In e O O � r r � tI ul 09'►694'13 'µ+l J N To Ls'"" 'is 'Aul CO ea'ieb '13 'PuiO a0 9� :ul • M09+1'l8 0 u1BY"9tr'I3'Aul N irlO9V'469f'13'Aul �0'L890'13'Pw0 N G 9� :ul • 906'as+1'no N W +K ul Z 1069,r 13 'Aul *la 'nul o J 7nOL6'4a9f N @ ►9'a690'13'PLUO 1L:Ln LL9'L6+L1IB O 8 a W La'6a94'13 'Aui ;no LB'669f 'l3 'Aul ►V9690 ,13 'PuUo s :U, • M'96+1 see 0 ulHIM '13 Aul J ;no 11'ea91r'l3 'Aul EVIN4'13 w LL :u1 • 9aB69+0 gig J ul ts'ea9Y'13 'Aw IM0 i9'ta91r '13 'eul a<c969V'13'PUJo aa'aa+o w® — o 8 8 8 8 8 0 w 1 i i i i i i i i 0 0 0 0 0 0 N V O 0 m o a a V a a e W 0 n in0 04'LdB4'13 'nul 60'1624 '13 'P WD 1 t :w ewes+O ne t a W m z O g In O J IN0 W O J U1 a L' LE64 '13 'DUI 1n0 e4' Le" '13 'Aul LO'L894'13'P��D 00'00+0 %8 0 o 8 g o III N poi O co co m a W 1 1 U) O N O I 1 1 1 O O Op ppO OOi a Ch a W e V pOp O pOp V N ino co 4eQ4 ' 13 'Aul ao•ee94 '13 'PW o LL •ul 469 QL+Z w18 N 0 N n O In Q LLJ u19L'4894'13'Aul Z 4r[091'{M94'13'Aul J 111,189413'PUM N OL :u-I.94L•4t+1 148 O F- N Ul L8'9e94.13 'Aw sno 4Q'se94'13 •AU, 92•L694 'l3 ' P W p el, tn-e6'9Q+0AB n I O � J uj W � J N 2 UI OL'E694'13 'Aul Ina CLIE60'13 'AEI 4B'L894'13'P��D Oe'00+0 ■l8 0 o o 0 0 0 8 W E N C m 1 N N E 0 O CD O N O i V M 4= O a 1 1 a a a a a a m 0 c� Q _Z J o L N U y N a ;no go, v f''13'nul roi tC'QeOti '13 'PuiO aL :u-I" aie'ec+o nH O J N 0 W O J ul EO'j4@V 13 'Aul incLe'ee" Is'Aul B9'A894 '13 'pu+D OG'00+0 ■iH 0 o 0 0 0 0 0 r $ y v � $ ad �i N PO a>i 2 e Tj 11 L I c 0 u e 7 T 7 H N N N m m m N N N N N N N N N N N N N N N N c O c O c O c O c O c O C O C O c O c O c O c O c O c O c O c O c O c O c O c O c O c O m z Z Z Z Z z z z z Z Z Z Z z Z Z Z z z Z Z Z o N a m c c 0 a c W N M V )O N r m m M m m (D V m O N N pJ2 m c m C7 m O m M o O m m r N m O o m m m r o o v p m m � Q m m � J V c O) 0)m N M m V m V m N 0) M O m m m N m M V m V V m r V O m V 0) a0 p 01 m 0V m � m m 0) t0 m 0) N N m m M m r v a v v v v x o e v a v v v a a o v a v v v e mo N m M m O m M O O O M n N m O O_ m m N m a m m V N N m m N J co rn N m M m a W t m fV m M m V m f0 m m N m N A M V m (O V m n 9 'C m N V 0 m 0 N � m m N V. 6^ m m O) m m m m d x 7 o v v a v v v v a v v a v v a v a v v o v v E 0 OD st N M V r NV O m m r n V m r O o a � O v m r V N c O � N M V N N m M O m Cl) N r M M V V V n V m V V O a m � m O mg a J 3 m m m m m m m m m m m m m m m m m m m m m m m m m m m 0) m m m m m 0) E t9 0^ w v v v v v v v v It It IT m v m It m It m v m v m It m It m a m v m v z xp m r o o 0 o 0 o o M v 0) U) C o o i0 CD m m m o m co n )n n u) m o m m )n 0 v o v O v m m O o O m m v m u') n o— 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 6 o cS o J m N m O n r r m n m N m m <o v, r M so r co n eo V r m s. to m o m Y? m O N M th N M m N M M V o 0V M V O m m m m m m m m m m m m m m m m m m m m m m m m OD V m V m v m V m V m V m V m v m V m V m m m m m m m m m m m m C W Z^. 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V M V W N x Go o W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 W 0 m 0 C 0 m W m W N M O M M m N W M N m rW r m �p W O r m N r V r r m m O t0 m N M M a m M M m V N M M m M M M V Nt V t0 V m V N M W M V m M m E m m m CD W CD m W W W W W W W W W W W W W m > C G m m m m m m m m m m m m m m m m m m m m m m Z c p v v v v v v v v v a a v a v v v v v v v v v n m 0 0 0 0 v m O 0 0 0 0 v 0 0 0 0 o m c m m m m m co r r m m In m v v o o <o m m m r to 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ID C O V v m m N 0) V N N N N m m m V V N N m m m N _ C m N N N - - - - m to O O N_ O O m m W O M W V m W r m to m N m m O N V M N m m m O N N aD W 7 m aD W W N m a i W M v V V V M M N Cl) N M O O O O M N CD m °i O O O O O O O O O O O O O O OCL O O O O O X G ao o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o a m w 'V N Go O O O o O O O O O O O O o O O O O O O O v m co d 0 O r W m 0)a m a V V OR OR o r W r O N M M M O O M W m N m N m N d 0 F F U � O 0V 0V 0V 0V O O O O O O G O O O O O O II N C L O O O O O O O O O O O O O O O O O O O O O O U r C m O m r r N V W N T E CD m m m M co Cl) O O O N N O 0) P.:O O N V O O N N N W r M M N N O O O N N N O o M N O O } II ~ m C O O O O O O 0 o O O O O O O O O O O O O0 O0 O O 'y c E o c o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 d c 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 o O O 09 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X m 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o r m LD o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a e o 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 c m 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O O o 0 o M � o U 0 0 0 0 0 0 0 0 o c c c 0 0 0 0 0 0 0 0 0 0 E c E_ m o u o 0 0 0 0 0 0 o 0 O 0 O 0 o 0 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 0 0 o 0 • W am 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0, € m o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 S E u u o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o ro p c ta, 0 C 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m 0 r N W m m r r m m V O m m m O W r m o m O 00`1 m W m O m N Cl) o m m W W 0 m m r CDm r O II C m r N t- M M N O M m O W m 0 O m r O O m m O Z, m M o r Qj r r 0 m M 6 N 0 r 6 m 6 m 0 O r m v V m m m N N N m M m M C F J W N Cl) V to N r m m M m m v N LL C O ~ m W O N d Z N J N M V m m r m W N N N I 1 L ATTACHMENT D IMPERVIOUSNESS COMPARISON TABLE ' NorthernEngineering.com // 970.221.4158 ■� I NORTHERN ENGINEERING 374-020 Brookfield Second Replat IMPERVIOUSNESS COMPARISON TABLE Northern Engineering Drainage Memo(1) TST Drainiage Report(2) DESIGN POINT BASIN ID AREA (acres) % Impervious BASIN ID AREA (acres) % Impervious D2A OF-1 & D-2A 0.27 79% D2 1.62 81% 45 D-213 0.53 51% 42 D-213 & D-2C (not a art) 0.77 1 73% D3A D-3A 0.44 66% D3 2.73 67% 43 D-36 1.27 69% D3C D-3C 0.61 49% 44 D-5/92 - - D5, D9 Proposed Future Commercial 46 D-7 0.30 57% D7 0.25 86% 51 D-7.1 0.33 65% D7.1 0.22 86% 52 D-7.2 0.33 68% D7.2 0.79 86% 47 D-8 0.33 63% D8 0.29 83% 48 D-8.1 0.33 70% D8.1 0.22 83% 54 D-10 0.39 59% D10 0.32 86% 56 D11a & D11b 0.46 68% D11 0.14, 86% 60 OF-1 0.44 8% Not a Part of Site OF2 OF-2 0.15 58% Not a Part of Site Totals: 6.94 53% Totals: 6.58 71% (1) - Drainage Memorandum for Brookfield Second Replat by Northern Engineering dated December 7, 2015 (2) - Final Drainage Report for Brookfield by TST dated December 14, 2001 D:\Projects\374-020\Drainage\Hydrology\374-020_Proposed_Rational_Calcs.xlsx 12/7/2015 ATTACHMENT E LOW IMPACT DEVELOPMENT CONFORMANCE REPORT t 1 NorthernEngineering.com // 970121.4158 1 ' INORTHERN ENGINEERING ' LID Conformance Report Date: January 25, 2016 Project: Brookfield Second Replat, Lots 1-12, Tract E and a portion of Tract D Project No. 374-020 Fort Collins, CO ' Attn: Stormwater Staff City of Fort Collins Stormwater Utility 700 Wood Street ' Fort Collins, CO 80521 Stormwater Staff: ' This letter serves to document conformance of the above referenced project with City of Fort Collins Low Impact Development (LID) requirements. In particular, the project is meeting Section 3.1 of the Fort Collins Stormwater Amendments to the Urban Drainage and Flood Control District Criteria Manual, including Section ' 3.1 (a)(1) requiring that no less than 50% of any newly added impervious area be treated using one or more LID techniques and Section 3.1(a)(2) requiring that no less than 25% of all new paving use a permeable pavement technology that is considered an LID technique. ' Section 3.1(a)(1) The project as a whole is proposing 2.997 acres of new on -site impervious area. This results in a minimum required LID treatment area of 1.498 acres. ' The project is treating 0.740 acres of on -site impervious area by pavers (directly or indirectly). The project is treating 0.260 acres of on -site impervious areas and 0.113 acres of off -site impervious areas using a Bio Swale with Soft Bottom. Runoff from the east half of a portion of Brookfield Drive flows along the curb and gutter to a 4' concrete chase under the sidewalk and into the Bio Swale. Low flows along the gutter will flow into the north side of the Bio Swale by the concrete chase and high flows will continue south along ' the curb and gutter as historically designed. The Bio Swale with Soft Bottom is designed with an underdrain perforated pipe, two clean -outs and a 12-inch grate inlet to keep ponding to the designed depth of 0.1-feet. During a major storm event flows will bypass the 12-inch grate inlet and will flow out a 2' metal chase under the sidewalk on the south side of the Bio Swale. The project is treating 0.835 acres of on -site impervious areas and 0.407 acres of off -site impervious areas using a treatment train of pavers, inlet snout, rain garden, forebay and dry well. Runoff from the north half of Le Fever Drive flows along the curb and gutter to a 4' concrete chase under the sidewalk and into a 3-feet deep concrete forebay before entering the Rain Garden. Low flows along the gutter will flow into the Rain Garden by the concrete chase and high flows will continue south along the curb and gutter as historically designed. The Rain Garden is designed with an underdrain perforated pipe, two clean -outs and a 12-inch ' grate inlet. Water quality capture volume is 466-cubic feet and a design depth of 0.44-feet. During a major storm event flows will bypass the 12-inch grate inlet and will flow out the 4-feet concrete chase under the sidewalk and down the curb and gutter south along Northern Lights Drive. Runoff from the south half of Le Fever Drive flows along the curb and gutter to a curb inlet on Northern Lights Drive. Surface flow upstream of the permeable pavers is captured by an underdrain and into the storm sewer line. Flow within the storm sewer line will be treated by a snout that will remove floating debris and oil at the area inlet located in the ' 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com ' NORTHERN ENGINEERING driveway. Low flows within the storm sewer line will flow to a Dry Well located east of the rain garden. High ' flows within the storm sewer line will flow south along Northern Lights Drive within the proposed storm sewer line and outlet to Pond A. The Dry Well will receive low flows from the storm sewer line and flows from the underdrain in the Rain Garden. The Dry Well has a capacity of 1395 cubic feet; calculations are included herein. ' The total on -site project area treated by LID techniques is 1.776 acres, which is 59.3% of the total new impervious area. Section 3.1(a)(2) The project as a whole is proposing 0.944 acres of new impervious paving. This results in a minimum required permeable paving area of 0.236 acres. The project has evaluated various areas for pavers to ' provide LID treatment to multiple areas of the Site. The total area of permeable pavers provided by the project is 0.243 acres, which is 25.8% of the total new paving. ' An exhibit has been provided to illustrate the topics outlined, and calculations supporting the LID techniques. Please feel free to contact me if you have any questions. Sincerely, ' Amber Morse Project Engineer ATTACHMENTS: Low Impact Development (LID) Treatment Exhibit Bio Swale with Soft Bottom Calculation ' Rain Garden Calculation Rain Garden Stage Storage Drywell Detail Drywell Capacity Calculation ' Low Flow Pipe to Dry Well Flow Calculation ' 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 I 970.221.4158 I www.northernengineering.com I I C 1 1 1 1 1 I VOIR �N_E D� CH - FOSSIL CREEK RESER — f DRY WELL WQCV VOLUME = 1286 CF DESIGN VOLUME = 1395 CF RAIN GARDEN REQUIRED WQCV = 466 CF i DESIGN VOLUME = 1,300 CF I d I i — — — PERMEABLE — — PAVEMENT — — SOUTHEAST / 12" GRATE \ 1 8-INCH PVC , - •- 2.71 CFS FULL -FLOW i CAPACITY MH A5 / LOW FLOW T TO DRY WELL - ... — ... .. . HIGH FLOW CONTINUES IN i STORM SEWER I I I I r- I 1 I I 1 I 1 1 1 I LIGHTS DRIVE PERMEABLE PAVEMENT �1• •ICI-I�r� SOUTH CENTER �0i�01 _ BROOKFIELD DRIVE _ PERMEABLE ASE 2' METAL CHASE PAVEMENT 4' CONCRETE CH — - _ HIGH FLOW TO STREET SOUTHWEST ---'— - LOW FLOW INTO BID SWALE - 2016.01.21 W I NORTHERN ENGINEERING D*RaECl 74.02MDWPFMXIaITsm4 020 uo.vW4 w 0 z O I U W W al LEGEND: I IN FEET I , INCN = 7a Fsrr PROPOSED CONTOUR EXISTING CONTOUR — —un:,— — LID BOUNDARY - — _ — — — - EXISTING STORM SEWER PROPOSED STORM SEWER o 11­1 ­ I 1<. /I//II/I//Nn RUI AREA FOR PERMEABLE PAVERSOFF-SITE IMPERMEABLE AREA j/%///J/ /�//�T�///���� TREATED BY LID TREATED j// f////ll ' fL ll/ , 50% On -Site Treatment by UD Requirement New On -Site lmpervlous Area 1.997 Ac. PaverArea 0.243 Ac. Traditional PavementArea 0.701 Ac. Other Impervious Surfaces (Roofs, Concrete Walks, etc.) 0.393 Ac. Required Minimum Impervious Area to be Treated 1.498 Ac. Paver LID Treatment Paverarea North 0.053 Ac. Run-on area for Paver North 0.006 Ac. Paverarea Southwest 0.050 Ac. Run-on area for Paver Southwest 0.143 Ac. Paverarea South Center 0.072 Ac. Run-on area for Paver South Center 0.146 Ac. Paverarea Southeast 0.069 Ac. Run-on area for Paver Southeast 0.202 Ac. Impervious Area Treated by LID Pavers 0.740 Ac. Dry Well Treatment On -Site Impervious Area Treated by Dry Well 0.935 Ac. Off -Site ImperviousArea Treated by Dry Well 0.407 Ac. Bic, Swak with Soft Bottom Treatment Bio Swale area 0.145 Ac. On -Site Impervious Area Treated by Bio Swale 0.260 Ac. Off -Site Impervious Area Treated by Bio Swale 0.113 Ac. Total On -Site Impervious Area Treated L776 Ac. Percent of On -Site Impervious Area Treated 59.3 % 25% Permeable Pavement Requirement New PavementArea 0.944 Ac. Required Minimum Area of Permeable Pavement 0.236Ac. Total Permeable PavementArea 0.243 Ac. Actual %of Permeable Pavement Provided 25.8 % FOR LID REVIEW ONLY NOT FOR CONSTRUCTION BROOKFI ELD I t 1 1 1 1 Design Procedure Form: Grass Swale (GS) Sheet 1 of 1 Designer: A. Morse Company: Northern Engineering Date: December 7, 2015 Project: Brookfield 374-020 Location: Bio Swale with Soft Bottom 1. Design Discharge for 2-Year Return Period �� = 0.30 cfs 2. Hydraulic Residence Time A) : Length of Grass Swale Ls = 140.0 If B) Calculated Residence Time (based on design velocity below) THR= 6.5 minutes 3. Longitudinal Slope (vertical distance per unit horizontal) A) Available Slope (based on site constraints) Sa,a,i = ft/ ft B) Design Slope So = 0.010 ft/ ft 4. Swale Geometry A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft/ h 8) Bottom Width of Swale (enter 0 for triangular section) We = 8.00 it 5. Vegetation A) Type of Planting (seed vs. sod, affects vegetal retardance factor) QQ Grass From Seed 0 Grass From Sod 6. Design Velocity (0.467 ft / s maximum for desirable 5-minute residence time) Vz = 0.36 s Us 7. Design Flow Depth (1 foot maximum) Dz = 0.10 ft A) Flow Area Az = 0.8 sq ft B) Top Width of Swale WT = 8.8 ft C) Froude Number (0.50 maximum) F = 0.20 D) Hydraulic Radius RH = 0.10 E) Velocity -Hydraulic Radius Product for Vegetal Retardance VR = 0.03 F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.080 G) Cumulative Height of Grade Control Structures Required Ho = 0.00 ft Uvow One AN UNDERDRAIN IS 8. Underdrain (Is an underdrain necessary?) Q YES Q NO REQUIRED IF THE DESIGN SLOPE < 2.0%, 9. Soil Preparation (Describe soil amendment) 10. Irrigation r I Q Temporary Q Permanent Notes: ' 374-020_RG_UD.xlsm, GS 12/7/2015, 11:14 AM ' NORTHERN ENGINEERING Brookfield 374-020 Stage - Storage Calculation Project Number: 374-020 Project Location: City of Fort Collins. CO Calculations By: A. Morse Date: 1/21/2016 Pond No.: Rain Garden Required Volume Water Surface Elevation (WSE) Design Point Design Storm 2-yr Require Volume= acft Design Storm WOCV Required Volume= 466 ft Contour Elevation (Y values) Contour Area Depth Column Not Used Incremental Volume Total Volume Total Volume ft, ft ft ft acre-feet 4,896.90 937.50 0.00 0 0 0 0 4,897.00 1007.30 0.10 97 97 0.00 4,897.20 1155.41 0.20 216 313 0.01 4,897.40 1311.36 0.20 246 559 0.01 4,897.60 1464.95 0.20 277 836 0.02 4,897.80 1631.62 0.20 309 1146 0.03 4,898,001 1827.14 0.20 345 1491 0.03 1 1/21/20168:34 AM D:IProjectsl374-0201DrainagelLID1374-020_RG Stage Storage. xlsmlStage_Storage_RG I 1 1 1 1 1 1 I Design Procedure Form: Rain Garden (RG) Sheet 1 of 2 Designer: A. Morse Company: Northern Engineering Data: December 7, 2015 Project: Brookfield 374-020 Location: Rain Garden 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I, = 63.0 % (100% 6 all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = IJ10(0) i = 0.630 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.20 watershed inches (W QCV= 0.8' (0.91' i'- 1.19' it- 0.78 - i) D) Contributing Watershed Area (including rein garden area) Area = 28,320 sq 8 E) Water Quality Capture Volume (WQCV) Design Volume VwOcv = 486 cu 8 Vol = (WQCV / 12)' Area F) For Watersheds Outside of the Denver Region, Depth of dS = in Average Runoff Producing Stone G) For Watersheds Outside of the Denver Region, VWOCV OTHER = 0.0 cu 8 Water Quality Capture Volume (WOCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWay USER = cu If (Only a a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwocv = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz list per unit vertical) 2 = 4.00. 0 / R (Use "0' a min garden has vertical walls) C) Minimum Flat Surface Area AM„ = 310 act 8 0) Actual Fiat Surface Area AM, = 936 sq % E) Area at Design Depth (Top Surface Area) ATm = 1800 sq ft F) Rain Garden Total Volume VT= 1,368 cu If (Vr= ((ATm * Arre,y)12)' Depth) 3. Growing Media Dose One ® 16" Rain Garden GroMng Mace Omer (e plain): 4. Underdmin System choose one A) Are underdrains provided? fo YES Q NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lovmsl Elevation of the Storage y= ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours V011= WA cu If iA) Orifice Diameter, 3/8" Minimum Do = N/A in ' 374-020_RG_UD.Asm, RG 121712015. 11:54 AM I J 1 1 1 1 1 1 Design Procedure Form: Rain Garden (RG) Sher 2 of " Designer A. Morse Company: Northam Engmeenng Dale: December 7, 2015 Project: Brookfield 374-020 Location: Rain Garden choose Olt 5. Impermeable Geomembrane Liner and Geolextile Separator Fabric O y6 A) Is an impermeable liner provided due to proximity Q NO 71 of structures or gmundwater contamination? 6. Inlet / Outlet Control Choose One IS Sheet Flow No Energy Dissipation Required A) Inlet Control Q Concentrated Flom Energy Dissipation Prwlded rh- 7. Vegeudion Q Seed (Plan for frequent weed control) Q plantings Q Sand Grown or Other High Mkir lon Sod 8. Irrigation Dose One ® YES NO SPRINKLER HEADS ON FIAT SURFACE 71 A) Will Me rain garden be irrigated? ONO Notes ' 374-020_RG_UD.xlsm, RG 1217/2015, 11:54 AM ,�-RIM ELEV-4696.2 48" DRYWELL MANHOLE 1 C D 4GRADE RING (SHOWN) 2 4- h 6" AVAILABLE ECCENTRIC CONE (SHOWN) CONCENTRIC CONE (OPTIONAL) 0 0 O 0 0 0 6 I/3" TYP 0 O 0 0 0 0 —,, 0 0 O O 0 0 0 0 0 0 0 0 5'-0" DRYWELL SECTION xI5'-0' 0 0 PERFORATED WITH 14 0 COLUMNS OF 2 3/e'e HOLES, 0 0 0 O' 8 HOLES IN EACH COLUMN 012 TOTAL). O 0 0 0 0 0 0 0 0 0 0 0 6 1/2- TYP. 0 0 0 0 0 0 �- 0 0 0 O 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 O O 0 0 E 1/2" TYP. 0 0 O 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 5'-0' 10 0 0 0 0 0 0 0 0 0 0 0 0 ORYYVELL SLAP • 4861 3e 0 0 0 0 0 0 0 0 0 0 0 -ICI 5` 4'-0" I.D. 4'-10. OD SECTION VIEW TOP 02 WITH GEOFA13RIC WHERE INTERFACED WITH NATIVE MATERIALS �- 8' PVC INV IN (SW) • 4892.53' (UPSTREAM MHA5 NIGH FLOW INV OUT (S) • 4893.33') 9ACKFILL WITH UNIFORM GRADED STORAGE ROCK TO TOP OF PERFORATED SECTION ------- 6ASE UNIT (OPTIONAL) WEIGHT: CITY OF VANCOUVER DRYWELL IS MANUFACTURED WITH PERFORATIONS ANGLED DOWNWARD TO THE OUTSIDE: ALL JOINTS ARE INVERTED. 5' BED GIN MIN I' OUTSIDE; COUNTY DRYWELL IS MANUFACTURED COMPACTED WITH FOUR 6'e DRAINAGE HOLES IN THE BASE IR ROCK 6LAB. 48" DRYWELL MANHOLE 0 Oldcasft Precast' File Name,020EMM48D-MH 48" DRYWELL MANHOLE PO Box 323, Wilsonville, Oregon 97070-0323 Issue Date: 2-16-2013 Tel: (503) 682.2844 Fax: (503) 682-2657 oldcastleprecast.com/wilsonville DRYWELL BASE TO STORM MANHOLE NORTHERN ENGINEERING PROJECT: JOB #: t/Z 13 rcb4' /Vj 7`I -020 c3 DATE: ,S - /Z-0 i ' A r)-c- Neu \a = 1 L ' c, co Q cv - c,- k z-vl . 0-- o. g Q _ 22 w4i-c rake C/�Qcv� 4,gCo.9l ��-1,19L,Z 7S�J ,n�4.es Cs a, `t`15 cc,o- ee \! o\ww. jz Dr l tD CA Y-,7-- \-fv e4 ' 5 udi�- Arl W-e, �l �w�P I'W�c,r CFXl2 Lt y0\6x-NQ. wit1 Acb .W c\\ h = 1\•� � c�D cF NORTHERN ENGINEERING PROJECT: JOB : Zrbok�,-eX4 2v 7 Lk -UZ D DATE oZOI S- 1 2--07 r cc-Leac , \,fouvn .Q 1 Cx�•�\ b �1 , ' Dnn�� all �� l►.GS' Wi\1 a'\t;�Y�.ess �lo4e Capac�• yore vo,'d Sju2 v-F G \ 11.�rs - cYLa.Y�1�r (.e7s) a s A 4IS- CIRCULAR CONDUIT FLOW (Normal & Critical Depth Computation) Project: 374-020 Brookfield Pipe ID: Low Flow Pipe to Dry Well from MH A5 - 2-YR Flow is 0.72 cfs f Tc Ytaw Arw� Y V gn Information (Input) Invert Slope So = 0.0500 ft/ft Manning's n-value n = 0.0130 Diameter D = 8.00 inches gn discharge Q = 0.72 cfs flow area Af = 0.35 sq ft flow wetted perimeter Pf = 2.09 ft Central Angle Theta = 3.14 radians -flow capacity Qf = 2.71 cfs :ulation of Normal Flow Condition Central Angle (0<Theta<3.14) Theta = 1.27 radians area An = 0.11 sq ft width Tn = 0.64 ft led perimeter Pn = 0.85 ft depth Yn = 0.23 ft velocity Vn = 6.56 fps :harge Qn = 0.72 cfs :ent Full Flow Flow = 26.57% of full flow nal Depth Froude Number Fr, =1 2.79 supercritic Central Angle (0<Theta-c<3.14) Theta-c = 1.77 radians :al flow area Ac = 0.22 sq ft ;al top width Tc = 0.65 ft cal flow depth Yc = 0.40 ft ;al flow velocity Vc = 3.29 fps -al Depth Froude Number Fr = 1.00 374-020_Low Flow Pipe to DW_UD-Culvert.xls, Pipe 12/3/2015, 12:19 PM ATTACHMENT F ' RAIN GARDEN - COMPLIANCE WITH COLORADO STATUTE §37-92-602 (8) t 1 1 1 1 1 1 ' NorthernEngineering.com /1 970.221.4158 Stormwater Detention and Infiltration Design Data Sheet Brookfield -374-020 Stormwater Facility Name: Rain Garden Facility Location & Jurisdiction: User (input) Watershed Characteristics Watershed Slope = 0.005 ft/ft Watershed Length -to -Width Ratio= 2.66 L:W Watershed Area = 1.58 acres Watershed Imperviousness= 71.0% percent Percentage Hydrologic Soil Group A = 0.0% percent Percentage Hydrologic Soil Group B = 50.0% percent Percentage Hydrologic Soil Groups C/D = 50.0% percent User Input: Detention Basin Characteristics WQCV Design Drain Time = 12.00 hours After completing and printing this worksheet to a pdf, go to: httos:/ImaDerture.dieitaldatasemices.com/evh/?viewer=cswdif create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed H dro ra h Results ' Design Storm Return Period = Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = ' Inflow Hydrograph Volume = Time to Drain 97%of Inflow Volume Time to Drain 99%of Inflow Volume = ' Maximum Ponding Depth - Maximum Ponded Area = Maximum Volume Stored = January 25, 2016 User Defined Stage Iftl User Defined Area Ift"21 User Defined Stage Iftl User Defined Discharge Icfsl Discharge Method 0.00 938 0.00 0.00 4in Slotted Pipc 4in Slotted Pipe 4in Slotted Pipe 12" Grate 12" Grate 12" Grate 12" Grate & 4' Chase to Gut 0.10 1,007 0.10 0.05 0.30 1,155 0.30 0.05 0.50 1,311 0.50 0.05 0.70 1,465 0,70 1 0.64 0.90 1,632 0.90 0.85 1.10 1,827 1.00 0.96 1.10 8.80 WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2.91 3.67 0.029 0.088 0.135 0.179 0.259 0.338 0.442 0.029 0.088 0.134 0.178 0.259 0.338 0,442 5 5 5 5 4 4 3 6 6 6 6 6 55 0.57 0.99 1.02 1.03 1.07 1.08 1.09 0,031 0.039 0,040 0.040 0.041 0.041 0.042 0.015 0.030 0.- 0.031 0.033 0.033 0.034 1 374-020_ SDI _ Design_Data_FC_Rainfall.xlsm, Design Data 1 er n cre-ft cre-ft cre-ft lours lours t cres cre-ft 1/21/2016, 9:20 AM I Stormwater Detention and Infiltration Design Data Sheet 9 —100YR IN - - 100YR OUT 8 ' -50YR IN - - - 50YR OUT 7 —25YR IN ' --- 25YR OUT 6 —10YR IN --- 10YR OUT S ' —SVR IN •••••• SYR OUT IN --2YR - 2YR OUT 3 —WQCV IN ' .....• WQCV OUT 2 1 0 - - w■�Lw�w���ww�Cwww� w�wl w�-�ww��liwww� w� ww�-�www�wlwww� ww�-�ww�w�www� `ww�-�ww�`wwww� 1�w�-�www�wlwww� \�w�--www�wlwww� ��w�-�www�wlwww� �\w�-�www�wlwww� � ww w�-�www�wlwww� ww n �www�wlwww� �ww�wlwww� awl p� trNlrarr��l1.1\� ' LJL ham\ www�wlww�� 4w�ureu�► ww��wwwm ���ww w � jmdm ww w�w mw / f///'Fw 1 R,� �Y\w: T •_ ww w�wlwwwl� wwri//�ran�►baa� ww��www� ��ww�� wwwin/LF/��i►►-]1��t�k1b.'M i��rn vu7n�� v�.� ww�w►ww�� �drn/v wwwrw►www� �i�i�����+err •n.�s � �� w��w►Iww�li� �is/J� in►i ZI+ww��wwwm / ��wt �wlwwwIW ' 0.1 2 1. 1 ' r 0.8 W 0 c 0.6 ' O 6 ' 0.4 0.2 ' 0 1 TIME [hr] 10 —100YR —50YR —25YR —10YR I —SYR —2YR —WQCV it I i i 0.2 1 ( 374-020_5DI_Design_Data_FC_Rainfall.zlsm, Design Data 1 DRAIN TIME [hr] 10 100 1/21/2016, 9:20 AM Channel Report ' Hydraflow Express Extension for Autodesk® AutoCAD@ Civil 3D® by Autodesk, Inc. 374-020 - Rain Garden - 4in Slotted PVC Pipe Circular Highlighted ' Diameter (ft) = 0.25 Depth (ft) Q (cfs) Area (sgft) 'Invert Elev (ft) = 100.00 Slope (%) = 0.40 Velocity (ft/s) Wetted Perim (ft) N-Value = 0.015 Crit Depth, Yc (ft) 'Top Calculations Width (ft) EGL (ft) Compute by: Q vs Depth No. Increments = 10 Elev (ft) 101.00 100.75 100.50 100.25 100.00 F'I:1fl.". 0 1 Monday, Jan 4 2016 = 0.25 = 0.048 = 0.05 = 0.99 = 0.79 = 0.14 = 0.00 = 0.27 Section Reach (ft) t00. V N 0 0 0 0 C, 0 cq CR 0 0 r 0 O CR CR 0 r Lei O N S h 0 C v 0 en 0 d w N O lV O O O_ O O O O O O O 000 t00 N O (sjo) H!aedeo ' Weir Report ' Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3DO by Autodesk, Inc. 374-020 - Rain Garden - Overflow Weir to Gutter 1 Rectangular Weir Highlighted = Sharp Depth (ft) 'Crest Bottom Length (ft) = 4.00 Q (cfs) Total Depth (ft) = 0.70 Area (sqft) Velocity (ft/s) Calculations Top Width (ft) Weir Coeff. Cw = 3.33 Compute by: Q vs Depth No. Increments = 10 1 Depth (ft) ' 1.00 0.50 t ' 0.00 -0.50 374-020 - Rain Garden - Overflow Weir to Gutter Weir W.S. Monday, Jan 4 2016 = 0.70 = 7.801 = 2.80 = 2.79 = 4.00 Depth (ft) 1.00 0.50 M 11116111 Length (ft) IIN I NII �• �\\ m �`�\,N ,m .<'N...�\• Eb ®E Ilfl\1 1111 \ If 1_ \:.._`:...: ``\ \ '`"\ oi'+"Ln p,\\ on\ \ 1 tl iYu2 VIM 2cI q ilzi Awn 'v WPM, mme j�I�II�i� .� ® NEVMAP LEGEND: � PROPOSED CONTOUR —sR EAISrRGGMTGR----ERNT- A PRMEmvaOMwRr RMIN ROMNDARY IS a EXISTING nURIN BUYER I �•SSIONP F� PROPOSEDSTORMSENER PERMpA&E PAVERS Z GJ UJ= A A w WUINIGEM&N BIMILE IMx �Z OE&MPOM Q OZ E Zw NOTES: L ME SZE TYPE AND LVCAnW OF ALL KNOWN UNDERGROUND UMAI ME APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SNAIL BE ME B RESPONSIBILITY OF ME CONTRACTOR TO ARIFY ME EXISTENCE CE ALL UNDERGROUND Jr-MEs IN ME AREA OF THE WORK BEFORE �g CW MENCHG NEW CMERUCTM ME CONTRACTOR RESPONSIBLE FOR OALL UNDERGROUND UYMES AND sHel1 BE N y RESPONSIBLE FOR FOR ALL unxnONN UNDERGROUND UNu R. KFER TO THE DRAINAGE WDJORANOUN BRCOxRELO SECOND REPLAY BY M NORTHERN ENGINEERING, DATED AUGUST ZB 2015 FOR ADDRONAL FORMAII Ci Bg S. HABITAT BUFFER ZONE IS TO BE MUNTAINEO IN A NADWE LANDI TME SECTM 14.1 CP ME LAND USE CODE FOR ALLOWASI£ USE "MIN E BUFFER ZONE. HABITAT BUFFER ZONE IS BETWLM ME LOT UPS AND EASTERN EDGE OF PEDESMAN TRAWL Si$E y{8 53 OF C a H w m Z O W WIN U) oQ FOR DRAINAGE REVIEW ONLY 1 j Z NOT FOR CONSTRUCTION ILL Q Y 0� O City of Fort Collins, Colorado Of UTILITY PLAN APPROVAL m MPRO D car uve D,N. MEMEO BY .'U" W uwnr R.N. MEMO BY: r O.l uUntMEMED BY Sheet D MEQ ED By D R 1 MECFED Bn. JIM, 26 Ot 38