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HomeMy WebLinkAboutSite Certifications - 11/21/2008October 13, 2008 Mr. Jay.Barber City of Fort Collins Storm Water Utility 700 Wood Street Fort Collins, CO 80521 J•R ENGINEERING A Westrian Company Re: Detention Pond and Drainage Certification for First Baptist Church JR Project 39322.27 y4 ro�i�f Dear Mr. Barber, We are submitting for your review and approval an overall site certification of the constructed drainage facilities for First Baptist Church. The storm water facilities appear to be in general conformance with the approved plans and drainage report. As -built shots of the site taken by JR Engineering show the location and dimensions of the drainage improvements constructed with the First Baptist Church site addition. Attached is the following: • The standard "Drainage Certification Form" used by the City of Fort Collins that provides a list of the various drainage items checked. • A pond volume summary showing the calculated proposed vs. as -built pond volumes. • A grading exhibit showing the proposed contours and spot elevations vs. the as -built contours and spot elevations for the pond and the outlet structure. Variations from the design were minor. The as built WQCV =0.012 acre feet which is equal to the amount required. The as -built detention volume=0.015 vs. the design volume of 0.0153. The water quality flow control plate was constructed per plan, and the outlet pipe was sized as 6" as specified. The outlet structure's dimensions varied slightly, but maintain the intent of the design. Differences in elevation and dimensions can be seen on the grading exhibit included with this submittal. Overall, the variations from plan are minimal, and the pond and outlet structure will operate as intended. In conclusion, based on the as -built survey information and our volume calculations based on these points, the drainage facilities for First Baptist Church have been constructed in general conformance to the approved plans. I find that the storm system as built, should operate as designed in the approved final drainage report. If you have any questions or comments, please contact me at (970) 491-9888. 2620 Fast Prospea Road, Suite 190, Fort Collins, CO 80525 970-491-9888 • Fax: 970-491-9984 • wJrenginmringxom �� 1b'ZZIX Prepared by: D e-- gIA ern,n Fecteau Design Engineer I Reviewed By: Michael D. Walker, PE Project Lead Engineer X:\3930000.all\3932227\Word\Letters\As-built Pond Cert.doc DRAINAGE CERTIFICATION FORM Please fill out all applicable items in this certification form for single family, multi -family and commercial properties. Write "OK" for items checked or actual number checked in field. Use "N/An for items that are not applicable to the property that is being certified. A. Drainage facilities certification 1. Pond Certification -volume verification oK a.topographic records and volume OK b.cross-sections and spot elevations O/� -positive fall to pan p/<- -side slopes . IV/A - &0A1eZE7P w4Z-L-s -invert elevation oK -spillway elevation O/l -placement and size of riprap/V//-1 -side slopes N114 -grading 6 1< -orifice plate installation and size- Q /� -compaction of berm Alor -structural integrity of pond 4AP91_?k,6 Q1,C' 2. Swales NA -location (are they within easement) -dimensions and cross-section verification -longitudinal slopes and side slopes -spot elevations _I Ufa -permanent erosion control measures (drop structures, riprap, etc....) -tie-in to pipes, pans, curbs, etc.... -weir size (elevations, size, opening, etc.) -available freeboard -landscaping infringement on swales 3. Pipes OA -size and type 4. -slopes (as -built and comparison to minimum 0.4% slope) -pipe capacity calculations if slopes are significantly altered -invert elevations -installation and backfill material -cover -encasement and clearance from other utility lines close by -joints Concrete Pan Channels -size -slope -super elevation -cross .section -thickness -elevations 5. Inlets Nl� -size and type e �JA -size of opening (or name of standard used) -grate elevation -invert elevation -box size `6. Cross pans ly� -size -type -grade -elevation -cross-sectional depth -tie-in to curb and gutter 7. Culverts NA -size -type -invert elevation -headwalls 8. Underdrains size -type -cover -backfill -geotextiles V -cleanouts 9. Curb cuts -size cfw< -tie in to swale, pipe, etc... 6 �� B. Certification of Grade Elevations Adjacent to Drainage Facilities: -minimum opening elevations O/< -top of foundation elevations d /< -comparison to 100 year WSEL's (Freeboard K requirements and floodplain issues) C. Certification of Erosion Control Measures: 1. Permanent Measures: -Permanent vegetation (6" bare spots and weeds under control) d K -riprap /VA -riprap bedding NA -drop sections Nq. -sediment basins/water quality ponds N)A -netting mats/blankets A -mulching © K 2. Temporary Measures: -mulching (n A/ -inlet filter installation N 4 -check bale dams !JA -seeding and temporary vegetation e)I( -silt fence OK D. Site Cleanup After Construction -construction clean up O/C -smoothing of ruts 014 -reseeding O/� E. Statement of Compliance This certification is signed and stamped and by signing this form the engineer(s) attests that they have inspected the site and to the best of their knowledge the as -built conditions of the drainage facilities are as described in the above form and in the redlined plans enclosed. Failure to properly disclose all known information could result in the rejection of this certification and prevent the release of any Stormwater Utility holds on Building Permits and/or Certificates of Occupancy. F. Signature and Stamp by a Colorado Registered Professional Engineer. 37687 '•.�ro•13-o Project First Baptist Pond Cart Project Number 39322.27 Date 101712008 Calculated By JPF WQCV 100 yr WSEL V=1 /3d(A+B+SQRT(A*B)) where V = volume between contours, ft3 d = depth between contours, ft A = surface area of contour Stage ft Surface area (ft) Incremental Volume (acre-ft) Total volume (acre-ft) WQCV (acre-ft) Detention Volume (acre-ft) 63.6 0.0 0.0000 64.2 18.8 0.0001 0.000 0.000 0.000 64.4 58.8 0.0002 0.000 0.000 0.000 64.6 137.9 0.0004 0.001 0.001 0.000 64.8 196.9 0.0008 0.001 0.001 0.000 65.0 268.7 0.0011 0.003 0.003 0.000 65.2 322.0 0.0014 0.004 0.004 0.000 65.4 373.7 0.0016 0.005 0.005 0.000 65.6 423.7 0.0018 0.007 0.007 0.000 65.8 469.1 0.0020 0.009 0.009 0.000 88.0 x: i 522 9 .. ;=, ` 0.0023 t 0.012 10.012 0.000 1= 66.2 571.2 0.0025 0.014 0.000 0.003 66.4 628.1 0.0028 0.017 0.000 0.005 66.6 693.8 0.0030 0.020 0.000 0.008 66.8 755.2 0.0033 0.023 0.000 0.012 67.0 '° : 4125.5 �"7 ., , ;1A0036 I 'r 0.027 I �OOOO .a; 40.015 `R APPROVED DESIGN Stacie Storage Incremental Volume Total Volume WQCV DET 64.1500 0.0000 0.0000 0.0000 0.0000 0.0000 64.2000 8.3100 0.0000 0.0000 0.0000 0.0000 64.4000 58.4400 0.0001 0.0001 0.0001 0.0000 64.6000 131.9600 0.0004 0.0006 0.0006 0.0000 64.8000 206.7900 0.0008 0.0013 0.0013 0.0000 65.0000 286.9300 0.0011 0.0025 0.0025 0.0000 65.2000 360.2900 0.0015 0.0039 0.0039 0.0000 65.6000 457.1900 0.0037 0.0077 0.0077 0.0000 65.8000 506.8100 0.0022 0.0099 0.0099 0.0000 66.0000 a _ 555.6600 ;, *;ft0 0024 -'r � 0.0123 . 10.0123 .'l0:0000 } 66.2000 602.3200 0.0027 0.0150 0.0000 0.0027 66.4000 646.8000 0.0029 0.0179 0.0000 0.0055 66.6000 688.8200 0.0031 0.0209 0.0000 0.0086 66.8000 729.7300 0.0033 0.0242 0.0006 0.0118 67.0000 I -; 1772.0600 !F "0;0034 :W : 0.0276 r; a0.0000 < ' 0.0153 :x• 67.2000 822.4200 0.0037 0.0313 0.0000 0.0190 67.4000 889.4400 0.0039 0.0352 0.0000 0.0229 67.6000 977.5100 0.0043 0.0395 0.0000 0.0272 67.8000 1108.7000 0.0048 0.0443 0.0000 0.0320 68.0000 1317.8400 0.0056 0.0499 0.0000 0.0375 i I 1, Water Quality volume.txt units=Elevation,ft,Area,ft2,volume,acft,volume,acft Elev Area Cumml Avg Cumml Conic ft ft2 acft acft 4968.0000 1317.8396 0.0499 0.0499 4967.8000 1108.7037 0.0444 0.0443 4967.6000 977.5073 0.0396 0.0395 4967.4000 889.4368 0.0353 0.0352 4967.2000 822.4207 0.0313 0.0313 g (✓���n'y ir���`� /00-7 4966.8000 729.77279 0.0242 0.0242 4966.6000 688.8268 0.0210 0.0209 c•r�ta3-`"� 4966.4000 646.8011 0.0179 0.0179 4966.2000 602.3222 0.0151 0.0150 p.Q&V- 4966.0000 4965.8000 555.6632 506.8165 0.0124 0.0100 0.0123--p 0.0099 a-w-- �9l�Co•t� 4965.6000 457.1900 0.0077 0.0077 4965.2000 360.2922 0.0040 0.0039 4965.0000 286.9348 0.0025 0.0025 4964.8000 206.7941 0.0014 0.0013 4964.6000 131.9634 0.0006 0.0006 4964.4000 58.4459 0.0002 0.0001 4964.2000 8.3120 0.0000 0.0000 • K. L Page f • Y aL Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility Designer: Company: Date: October 6, 2008 Project: Location: 1. Basin Storage Volume la = 56.80 % A) Tributary Area's Imperviousness Ratio (i = 18 / 100) i =1 0.57 1 B) Contributing Watershed Area (Area) - Area = 0.510 acres C) Water Quality Capture Volume (WQCV) WQCV = 0.23 watershed inches (WQCV =1.0' (0.91 ' I'- 1.1912+0.78' 1)) D) Design Volume: Vol = (WQCV / 12)' Area' 1.2 Vol = 00-1-1 5­1 acre-feet A- 2. Outlet Works A) Outlet Type (Check One) I Orifice Plate Perforated Riser Pipe Other: B) Depth at Outlet Above Lowest Perforation (H) H = feet C) Recommended Maximum Outlet Area per Row, (Ao) Ao = square inches D) Perforation Dimensions: i) Circular Perforation Diameter or D = 3 inches ii) Width of 2" High Rectangular Perforations W =) I inches E) Number of Columns (nc, See Table 6a-1 For Maximum) nc number F) Actual Design Outlet Area per Row (A,) Ae square inches G) Number of Rows (nr) nr =1- 1 number H) Total Outlet Area (A.) A. = c square inches 3. Trash Rack A) Needed Open Area: A, = 0.5 ' (Figure 7 Value) ' A., A, square inches B) Type of Outlet Opening (Check One) < 2" Diameter Round I 12" High Rectangular Other: C) For 2", or Smaller, Round Opening (Ref.: Figure 6a): i) Width of Trash Rack and Concrete Opening (Wwn,) from Table 6a-1 W.m = i inches ii) Height of Trash Rack Screen (HTR) HTR =,-�� inches EDB check.xls, EDB 10/6/2008, 7:36 PM 7 7 J ABED STORAGE & OUTLET WORKS: BASIN AREA = 0.510 <--INPUT from impervious calcs BASIN IMPERVIOUSNESS PERCENT = 56.80 <--INPUT from impervious calcs CF"Gvr`/7 BASIN IMPERVIOUSNESS RATIO =Rk-M } <--CALCULATED WQCV (watershed inches) _` CALCULATED from Figure EDB-2 WQCV (ac-ft) =1,, .'wx.A,i, <-- CALCULATED from UDFCD DCM V.3 Section 6.5 WO Depth (ft) = 1.850 <-- INPUT from stage -storage table Sec ED $ s?"_'AskA41- AREA REQUIRED PER ROW, a (in2) _ <-- CALCULATED from Figure EDB-3 CIRCULAR PERFORATION SIZING: dia (in) = 1/4 <-- INPUT from Figure 5 S. (in) = 1 <-- INPUT from Figure 5 n = 1 <-- INPUT from Figure 5 t (in) = 1/4 <-- INPUT from Figure 5 number of rows =XREs <-- CALCULATED from WC Depth and row spacing round to lowest whole -number = 5 <-- INPUT from above cell total outlet area (in2) _, NIX <-- CALCULATED from total number of wholes TRASH RACK DESIGN: Trash Rack Open Area Ratio <-- CALCULATED from Figure 7 Required Trash Rack Open Area (in 2) _ <-- CALCULATED from UDFCD DCM V.3 Section 6.6 Wconc (In) S`i° S <-- INPUT from Table 6a-1 Wplate (In) <-- INPUT from Figure 4 * DON'T FORGET WELL -SCREEN * N/A <-- INPUT from Table 6a-2 V W Uw ¢ IN Z0O WW6m Ip 6 �N 496 611 6 JVOanaUO Z� Atl F nZ}oiz IN 7�66<6006 �UO a U 4964.15 O yl 4988.09 IN - U VI 4963.80 w d z v.� wo 4966.00 K ����nnnn W s 4969 J9 _ / 49TOW Op CW / 50 4%8.09 Rt M {986 9{ PIC 'MO FOUNO� 4968.50 6855 W � 4 4i T� DTI 4968.5 W LL °9 I M9 T CW1011N (TP.) 49 0 55 _ N.T.S. W Z R OE9QI CWMTWR (T1P) 4968.50 \ 1'— 4965.7S 92� 'u � TOW /� 11///V//•� W 'b / qy6 0 4 In 4i AS 4 0 / T01 r TOW / 49 0 IT �4 .1 IN 4p+' INV. L� EpM/�MM rG R0/ A4-@IILT WIp CONTpIR g2ip3D MA" LdliplR lOR! W PRVOSU MWER awl" p N++�_ FOT FI Amm 1 yS 4966.50 PflM030 WWT flEVAT K < PRSO4D W/AL w f AS-BJILT PAN _ a \ u a 454 I PWPoSO PIN Y T Q a Z Im O O Im `o 4 o O U U � O x F U U J V) 7 PRfP4RiD um THE im;im sxmWsax a F F m cr 10 5 0 10 YO AS=BUILT 10/9/08 m a V) Z w o ` � a lid WLWMAM J� /0-13-Wi 91EET 7 0: 1 '. L.cxn wIL WMnm Wr.re RM Mo oR elwwr• w m muensw .ae No. 3932227