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Home My WebLink AboutSite Certifications - 11/09/2006TETRA TECH, INC. November 8, 2006 Mr. Guy Johnson D.R. Horton, The Melody Series 11031 Sheridan Boulevard Westminster, Colorado 80020 Re: Pond Certification for Rigden Farm Water Quality Pond #3 Tetra Tech Job # 80-0068.066.00 Dear Mr. Johnson: Using survey information provided by Mr. Brett Bolinger of Nolte, Inc., and Water Quality Pond #3 design information from the Final Drainage Report for Rigden Farms (provided by Mr. Mike Brake with JR Engineering), Tetra Tech has completed the volume computations to provide this letter of pond certification. The average end area' method was used to calculate the as -built volume for this water quality pond. The volume at elevation 4884 is 0.61 acre-ft. The design volume at that elevation is 0.56 acre-ft. The top of berm for the pond is elevation 4885 with a volume of 0.93 acre-ft versus a design volume of 0.85 acre-ft. Therefore, the as -built volume exceeds the design volume. Attached are copies of the as -built volume calculations and design calculations. If you have any questions or would like any additional information, please contact me. Sincerely, TETRA TECH, INC. d ' Q Catherine A. Leslie, P. Civil Engineering and Attachments HA0068_066\Pond Certification\WQ Pond 3 Cert.doc 1900 S. Sunset Street, Suite I -F, Longmont, CO 80501 Tel 303.772.5282 Fax 303.665.6959 www.ttrmc.com No Text -•.` Water Quality Ponds Along Foothills Regoinal Channel ll Proposed Detention Pond - Stage/Storage LOCATION: Rigden 2 PROJECT NO: 39164.12 COMPUTATIONS BY: B. Strand SUBMITTED BY: 1R ENGINEERING DATE 7/4101 V=113d(A+B+sgn(A'B)) where V = volume between contours, ft' d = depth between contours, it A - surface area of contour WA}Ar OnAtity Dnnd 1 Pond Inv. Pipe Inv Elev of WO orifice WQCV Top of WO structure top of berm Pond Inv. Pipe Inv Elev of WO orifice WQCV Top ofWQ structure top of berm Stage (it) Surface Area (it?) Incremental Storage ao-ft Total Storage (ao-ft) 4906.49 0 4907 255 0.00 0.00 4908 1,303 0.02 0.02 4908.2 1,582 0.01 0.02 4908.49 1,986 0.01 0.04 4009 2,696 0.03 0.06 4909.90 4,069 0.07 0.13 4910 4,222 0.01 0.14 4910.5 5,082 0.05 0.20 4911 5,941 0.12 0.26 4912 7,840 OA6 0.42 Wdar Aun11N Dnnd 9 Stage (it) Surface Area (fe) Incremental Storage (ao-ft) Total Storage (at>fl) 49D3 0 4904 337 0.00 0.00 4905 929 0.01 0.02 4905.3 1.199 0.01 0.02 4906 1,828 0.03 0.05 4906.60 2,637 0.03 0.08 4907 3,176 0.03 0.10 4907.3 3.741 0.02 0.13 4908 5,059 0.09 0.20 4909 6,569 0.13 0.33 1. Water Quality Pond 3 1 Pipe Inv Pond Inv. Elev of WO orifice Top WQ Struct/WQCV top of berm 39164wq-RII.xis - Stage (ft) Surface Area (fe) :Incremental Storage ac-ft) Total Storage (ac-ft) 4880 1 0 0.00 0.00 0.00 0.00 4880.84 0 4881 2.585. r 0.00 0.D0 4881.87 6,703 • 0.09 0.09 4882 7,318 i 0.11 0.11 4882.84 9,662, 0.16 0.28 4883 10,108 0.D4 0.31 4883.87 11,495. 0.22 0.53 4884 11,702 0.03 0.56- 4885 ' 13.480 0.29 0.85 Water Quality Pond Emergency Overflow Spillway Sizing r LOCATION: Rigden Farm - Filing Six PROJECT NO: 39264.12 COMPUTATIONS BY: B. STRAND SUBMITTED BY: JR ENGINEERING DATE: 9/26/01 4� Equation for flow over a broad crested weir _ Q=CLH'rz where C = weir coefficient = 2.6 LH = overflow height ~ T♦ L = length of the weir _ The pond has a spill elevation equal to the maximum water surface elevation in the pond Design spillway with 0.5 ft flow depth, thus H = 0.5 ft Size the spillway for Q(100). WQ POND 1 Q (100) = 33 cfs (peak flow into pond) Spill elev = 4912.00 It = 100-year WSEL Min top of berm elev.= 4913.00 r= Weir length required: L = =36 It Use L = 50 ft v = 1.65 ft/s WQ POND 2 Q (100) = 20 cfs (peak flow into pond) = Spill elev = 4908.00 ft = 100-year WSEL Min top of berm elev.= 4909.00 Weir length required: L'= 22 It Use L = 30 ft v = 1.56 fVs WQ POND 3 Q (100) = 139 cfs (peak flow into pond) Spill elev = 4884.00 ft = 100-year WSEL Min top of berm elev.= 4885.00 Weir length required: L = 115 It Use L = 112 ft (0.6ft flow depth) v = 2.34 ft/s GD" PARKWAY CALL UTILITY NOTIFICATION CENTER OF COLORADO 1.800-922-1987 = 2-BUSNESS DAYS IN -- - ADVANDE BEFORE YOU DIG, -- MADE. OR EXCAVATE FM DIE MARKING OF UNDERGROUND MEMBER UDUMES LEGEND EMSYNG PIPER R® PRGPGSED INLET AND PIPE PROPOSED INLET LOCATION -- — ENSTING 5- CONTOUR 50 35 0 10D —�_.-- ENSTING 1' C0 MR Sr•I r. 1' 30' PROPOSED 5' C MR ' pRDIrOSFD 100 YEAR HM - 40 Hbol — -4NSaM • car Cf T0IRw Oo61MG CM0... _. ' -... _ _ 1 _ • 70% _ ___ �� -. P� wFF Cii - smTsjjnqanti — • oDrRrcMi a - - - 1d _. : r MXM: THE aX•o-/ HE KEYMAP RM FI®N® uLF11 M oar 91FfXXVM a �S F iXC F.� of Fort CdINa o;'x aa9 i0€a 5Wu . V 606i is N V1€m0 p wz wzo�< z �w oa.n g�a� Z5aa<2�6oa' m N C � Ono amn O 1F0=N I C N ONO N N O� LLM 10 0 wzvv w 1ZMoi m 8 O � S �...JJJ 3 JJOzx N C�24 o �a 1 NOTES: 1. ALL RCP SHALL BE CLASS III UNLESS OTHER ISE NOTED. CHECKED BY. )VA 2. PRESSURE SEALSSHALL BE TYPE.'R'. I 3. PIPE LENGTHS ARE MEASURED FROM THE CE TER M ALL STRUCNRES.1 CHECKED BY: 4. ALL SYMM SEYiER SHALL BE MSKMD BY NE CITY OF FORT COLLINSI TMMC S ALL FES ARE INCLUDED N PIPE. LENGTHS I CHECKED BY: � nr. .wa<A6 oa.. 4925 i Xt _ _4920 >� S r N R $ I) o B II O] kid - 9 r 11 n m o r s \ 4915 ` n Md f ttj C} f11G14 ►m xa a� �Ila a E -- Oasmww uls� ._ . - -w sT ar ormolu of 4910 s o olavxe ET --SAwE • T�1 a1= a ux. - 4905 1 N _ s- y 2 3 btR J E J nos Z Lr �• z:i3 - r` 4900 cc 3 D- a N _ ..- Z 4895 J Z 4890 cD — — ---- _.. — - - i _ sHEET 110 OF 142 — _... 1400 dae NO. 39164.12 1L0o 0+00 V z 8� I:L w w zt- III 0<0< VOSIMN DW flwwG_K on W-1 48 0 zw�s F-C PM 'Ce 4 <00< j KEYMAP MISS -7 Z9 0a 7!2 L---- -------------- w Z > WAISUPLE l`fPE to wr WT m 1WECII&E U MIX un� mc !I 5 On ------ UU no >1Z T-�— — — — jm— -`OE — — r OZX n zo< M D TYPE 16 NLfT 1 ea mmia� 20 - - k -ti- - Slell-17A sleffle-la T. Ul- I'(PE L it 1\ �E JIM �4� UD I I I U I mw I mu I 11 --441- Z-ij I X x 0 U 2 u MWIFIF 14,11, (64', 64 24' I *OE Lu 0 Uj Z Illm 1 1 ATIM MUt wo LEGEND 9 Lu few EXISTING PIPES City of Fact CollInst Calarado SO 25 0 so 100 ME3000K:M 0 PROPOSED INLET AND PIK PROPOSED INUET LOCARON SO 25 0 SO 100 71TY M MAVAL A CALL UTILITY NOTIFICATION EXISTING 5' CONTOUR SCALE: I* - W CENTER OF COLORADO SCALD Id Sw EXISTING 1' CONTOUR r�ROM: COED ONE Este; OMNI" lw800-922ml987 NOTES: PROPOSED WCONTOUR 1. ALL REP SHALL BE CLASS III UNLESS ODIERNSE NOTED. CHE SY044 Q6U 2-BUSINESS OAtS IN PROPOSED I* CONTOUR 2. *PRESSURE SEALN JOINTS OSTANDARD SHALL BE IN ACCORDANCE INTH ASW C443, nilly gate �0? ADVANCE BEFORE YOU DIG, SKCIFICAnON FOR JOINTS FOR CIRCULAR CONCRETE SEVAER- CHECKED BY: A14 CWDC GRADE, OR EXCAVATE FOR THE AR WGL AND CULVERT PIK, USING RUBBER CASKEW a MARKING OF UNDERGROUND 3. PIPE LENGTHS ARE MEASURED FRW THE CENTER Of� AM SION.) TJRES MEMBER U111.1"RES. 4. ALL STORM SEWR SHALL BE INSPECXD By THE CITY OF FORT COLUN;B.� CROE01 BY., 5. AM M ME INCLUDED IN PIPE LENGIHS. CHEMED BY.� -------------------- 4920 M4 0 4920 7 J' 4915 .... 4915 4910--ot to" M� pit 4' --�Ooj 4910 OWN RON 4 + �7 6 4905 4905 Ea GO RIARMCE 4900 X =CT! ANTAIN Ell-PIN)FICET51) < a U NON f 4900 x 0 < Of Q INS 4895 1 x 1 "HIM. V) WAL NTS lwA 0 LLI M90 CAN.I. VOODOO z le 0 JIM 7 z V) < 4WO W JOB DOWMX� 2V I ANITNRY Me a smicemil Ala "ST 2r �TMRY �WR —1051',13-Or 4880 (1) n S L - ----- ---- sum settled lc� 4875 11ININ t 1-00 3+00 4+oo 5+00 ---- -60 —4 . 4875 SHUT 111 OF 142 2-60-3 . . . . . 0-0 .-Do 6 -00 7+00 JOB NO, OO68.D56.lO CALL UTILITY NOTFICATON CENTER OF COLORADO 1-800w922w1987 CALL 2-BUSNESS DAYS IN -- ADVANCE BEFORE YOU DID, GRADE OR EXCAVATE FOR THE MARKING OF UNDERGROUND .MEMBER UTLMES. 4930 4925 4920 4915 4910 it - .MCI 7iVJ 1 > _ R N ILO-1X N i _INN[ 4900- - 'a 4895I -. TM - EAw LAE A rnosslla-: - 4890 e' sww 4885. WIMM LEGEND ENSTNG PIPES 50 25 0 So IN ® PROPOSED NUT AND PIPE ■ PROPCSED INLET LOCATOU SOME: 1' 50 — — — ENSTNG 5' CONTOUR -- EXISTING V CONTOUR PROPOSED 5' CONTOUR ,. A;"4�■u xwyt:..'::-.��.Q: 1' CONTOUR �...— IN YEAR N0. a lip 'Jp WME NMM MGM S PINPAI® wom >� vIm aN■NNa1 a z pF 1NOP b City of Fort Collins, Colo raoo UTILITY PLAN PPROVAL APPPOVED: S/p CI EMt+w 001� CHECKED BY. /' 1. ALL RCP SHALL BE CLASS IN UNLESS 01 !ER■SE NOTED. CHECKED BY: E/�'!01[ `{ 2. 'PRESSURE SEAL' MINTS SHALL BE IN , :CORDMCE MTH ASYM CH3, ulmy oaa 'STANDARD SPEOACADDN FOR JOINTS F A ORCULAR CONCRETE SEVEN NECKED BY: Alm CULVERT PIPE. USING RUBBER GAS PS' F�v� I PIPE LENGTHS ARE MEASURED FROM TM CENTER W ALL STRUCTURES. l ALL STORM SEINER SHALL BE INSPECTED BT THE CITY OF FORT MUMS. CHECKED BY: TmR[ [np'new 5. ALL FES ARE INCLUDED IN PIPE LENGTH: I CHECKED BY: mN 4930 - 4925 umo �� E a - . M 4920 1N \ V1 N 4915 n _ Yi 4910 � 4905 E L! IA J - _ - - ruuTa wN • Z _ ti 0 0¢ -- — - - r r_aaerMs 4895 LL 1- Z -_ rn — w d _ -- - 4890 aaJ..77 — — — — D: —_. .--- 4885 sNUT 112 a 142 - ... 0 +00 1 00 2+00 JOB NO. 39164.12