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HomeMy WebLinkAboutLot Certifications - 01/10/2002 (3)t4CITE' BE Y O N D EN G IN E E R ING January 10, 2002 Job No. FC0125 Mr. Basil Hamdan City of Fort Collins Stormwater Utility 700 Wood Street P.O. Box 580 Fort Collins, Colorado 80522 SUBJECT: Drainage Certification foeBest Bay P. Dean Mr. Hamdan: The following serves as a summary of the record condition for the on -site detention pond and associated drainage facilities at the Best Buy retail store expansion. The survey data that serves as the.basis for the summary of the record condition was collected between June 28 h, 2001 and January 8m, 2002. The record information has been reviewed and checked for conformance with the approved Best Buy P.U.D. Final Drainage and Erosion Control Study (Approved: 10/10/00).and the approved Utility Plans (Approved: 10/23/00). A summary of this record condition is as follows: On -Site Detention Pond The on -site detention pond. was designed to detain 0.72 ac-ft at elevation 5029.15. This volume . included the Water Quality Capture Volume (WQCV). Exclusive of the WQCV, the approved detention pond was designed to detain 0.65 ac-ft during the 100-year storm event. Based on the record information, the on -site detention pond will detain 0.65 ac-ft at elevation 5029.19. The revised high water line was achieved by constructing an asphalt berm across the driveway that lies adjacent to the detention pond and along its south side. Water Quality Outlet Structure Based on the record information, the water quality outlet structure was built in substantial conformance with the approved Final Drainage and Erosion Control Study and the approved Utility Plans. The record condition for this structure is shown on Sheet C7. .Sub -Surface Storm Drainage Facilities The on -site sub -surface storm drainage facilities record condition is shown on Sheet C7. For each storm drain profile, the record information was listed along side the approved design. Storm Drain NOLTE ASSOCIATES, INC. 1901 SHARP POINT DRIVE, SUITE A FORT COLLINS, CO 80525 970.221.12400 T E L 9 7 0. 2 2 1. 2 4 1 5 FAX nAfc0125\document9\drainage =ti5cat;on4ord4dter hamdan 20020801.doc WWW.NOLTE.COM i Profile `C' does not coincide with the approved design. The record information indicates that an adverse grade condition exists (Le., -0.32% versus 0.54%). This will lead to ponding depths at the upstream end of the pipe (Le., inside the Water Quality. Outlet Structure) of 0.08' (-1") before the stormwater will drain as it was designed to. 'This condition will not affect the performance of the Water Quality Outlet Structure. With consideration to the aforementioned exceptions, we feel that the record condition. of the Best Buy retail store expansions in substantial conformance with the approved Final. Drainage and Erosion Control Study and approved Utility Plans. Sincerely, Nolte Associates, Inc. L �v� Tom Ochwat, P.E. Senior Engineer `,`A '`��Nli�a rrnhet•ir••i ,` se° �* Pr i -® o- 28810 - Dl- .� NOLTE ASSOCIATES, INC. nAfc01251docammWdrmn_agc cofificaficn\woMew Lamd>m 2002MI.doc � alx 5 a+yr 5040 J..- .".?C y-EXISTING GROUND 5000 m. WSCL- ��1935A0.)Be 3a4ixn 14"v23- CL I11 HERCP 14".23" CL I11 HERCP Rip -Rap Type L L=6' W = 6. D 16" VA MNE 6,ri` 50P0. 00 Ourw 1+00 2+00 STORM DRAIN PROFILE "A" NOR. Scale: I"=50' Vert. Scale: In was_e.+mu._wwym •� tir•L"•w Wwl MI bb r:=M Ir Viw1 •r sis san"I W�.•rMAM Ed If Iy.... IM1"" Io.ar go T mi. yv. E e a Psba Pa15sn. HIM t� r:t" y"b"W W s ,i""rt..�rr I.`".G`^"aMbI.... as ale '." .. SS 504� Oz +O In g EXISTING GROUND W30 K 100I F.SEL= L — 21w (2) Buried RipRW T pe 'L', = 12 VE = 6, D-16' DAEFEW ®d'V 608D 00 m 0+00 1+00 STORM DRAIN PROFILE "B" HATE. Santa. 1"-50' Vrt. Sadler 10-5' �a g ] NFIRM by iin�• IF max; ^ v m wK J VON 56 11 SO ON >z' 5040 33 'pz ✓, - _ SS EXISTING PROPOSED GROUND GRACE 503o S Im-ra..seL- IOU-M, WSE.Lyb Ri -Rap PROPOSED TYPE 'L' 1B" GL IN RCP 5030 MADE L=6 IN EXISTING I - 6" GROUND Y� DARd A46'V 5020. DD ENDO 1+00 ,.y.�`i.i`a`.�.'µ`r���"•w gyp` ..x..�w ar.nose r•M m•ti M� STORM DRAIN PROFILE "C" HATE. Scale: 1"-50' Vrt. Scale: 1"-5' ��2BeB-LF31.00 V 13.86 V f-1.96160.20i 2.BB;}8.655. 21" CL III RCP 21" G. IN RCP DARN IEW 50f280 0+0D 1+DO STORM DRAIN PROFILE "D" NOTE. SOME: 1'-50' Vert. Stale 1"=5' In- 1 ✓ram® .� PoP-RI Sr MI FEES I LENGTI "1 A' 1 L 1 6' i 16" lIF I L I IF I IF I6- mm S = WI INLET ON GRADE One, mw one osccnoxl NUR CONNECTED TO A CROSS CULVERT WmInne by INLET CONNECTED TO A INLET AT BOA SKEWED CROSS CULVERT DE VERTICAL CURVE ST In City of Fort Collins, Colorado UTILITY PLAN APPROVAL CHECKED BY: City of Fort Collins, Colorado UTILITY PLAN APPROVAL CHECKED BY: CHECKED GEM Mr.W O6a CHECKED BY: xtm 4 alum cHECNFD Br: rWN IEd.r CHECKED BY. STORM DRAIN PROFILES AND DETAILS NOTES: 1. ALL STATIONING, PIPE LENGTHS, AND INVERT ELEVATIONS GIVEN FOR STORM DRAIN DESGN ARE RELATIVE TO CENTER UNE OF STRUCTURES UNLESS OTHERWISE SPECIFIED. 2. ALL RCP SHALL BE CLASS III UNLESS NOTED OTHERWISE. 3, ALL PROPOSED STORM DRAIN TO BE INSPECTED BY CITY OF FORT COLLINS. Q T AT a.. 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