The URL can be used to link to this page

Home My WebLink AboutSite Certifications - 07/28/20141T=c) 'Scvo—'A 6/�/70Io{- — s�b•.�:{}4d „n /zs �ZOt4 V�.es reJ :...>.0 f �:d sill v;54 St1or}t7 '�1w..-dt 1F{tJ tscvoa+o�d ...J et:�.•t{' rrl:wt�d sF 'i Lt.5+L—�. BIG DEAL SUBDIVISION (�% ' esar a7 Gfl{.- Cityof (CCIn J��1 (q' t611 (C.M C_� 621 S MELDRUM STREET J,c{}"' f��t �1a•.« Slot, -200 � t COlUnS COMMERCIAL, MULTI -FAMILY AND SUBDIVISION CERTIFICATION CHECKLIST (Overall Site Drainage) Please fill in all applicable items in this Certification Form for Commercial, Multi -Family and Overall Single Family sites. A copy of the approved grading plan must be submitted with the as - built grading plan. (It is preferred to have the as -built elevations written in red next to the approved elevations) Use "OK" for items checked or actual numbers for items verified/surveyed in the field. Use "N/A" for items that are not applicable to the site that is being certified. Please provide an As -Built Redlined or Mylar drawing showing the following! INDICATES ITEM NOT CHECKED A. Detention, Drainage Facilities, and Common Open Spaces 1. Pond Certification OK • Provide Topographic Records and Volume Verification Calculations OK Provide Pond Cross -Sections and Spot Elevations (especially @ Pond Embankment and Pond Flow Line) N A . Positive Fall to Pan (if applicable) OK • General Pond Grading including all Side -Slopes OK • Invert Elevation N/A • Forebay Construction and Elevation )VIA • Spillway Weir (Location, Elevation, Height, Opening Width) N;A • Placement and size of riprap or alternative permanent erosion control measures OK • Orifice Plate and/or Water Quality Outlet Structure Installation NOTE • Water Quality Capture Volume (Volume Required, Volume Provided and Water Surface Elevation) • Berm and Embankment Compaction Level • Subsurface Media for Water Quality Ponds and Swales NOTE. A VARIANCE HAS BEEN ACCEPTED. SEE SUPPLEMENTAL LETTER. W I NORTHERN E NG I N E E R ANC BIG DEAL SUBDIVISION 42. S NR'DRUM SMU City of FOrt COltins 2. Swales NIA • Location (are they within easement?) OK • Dimension and Cross -Section Verification NOTE • Longitudinal Slopes and Side -Slopes OK • Spot Elevations OK • Permanent Erosion Control Measures (drop structures, riprap, lining) NOTE • Tie-in to Storm Lines, Pans, Curbs, or other appurtenances OK • Required Minimum Freeboard, Provided Freeboard OK . Landscaping Infringement on Flow Line? NOTE. SEE GRADING ASBUILTS AND REVISIONS. SWALES BUILT PER REVISIONS 3. Pipes OK • Size and Type NOTE • Slopes (As -Built and comparison to 0.4% Minimum) OK . Pipe Capacity Calculations (if slopes are significantly altered from design) NOTE • Invert Elevations • Installation and Backf ill OK • Cover • Encasement and Clearance from other nearby utility lines • Joints Type and construction NOTE. ENGINEER DID NOT OBSERVE CONSTRUCTION. INDEPENDENT ASBUILT SURVEY RELIED UPON FOR ELEVATIONS AND SLOPES. SEE ASBUILT. BIG DEAL SUBDIVISION NORTHERN ENGINEERING 2 6215 MELDNUM STREET For,. �`t��s 4. Concrete Pan Channels N/A • Size N/A • Slope N/A • Cross Section N/A • Thickness N/A • Elevations S. Inlets OK • Size and Type OK • Size of Opening for name of Standard Detail used) OK • Grate Elevation oK • Invert Elevation OK . Box Size 6. Street Cross -Pans N/A • Size N/A • Type N/A • Grade N/A • Elevations N/A • Cross -Sectional Depth N/A • Tie-in to Curb and Gutter NORTHERN BIG DEAL SUBDIVISION ENGINEERING 3 621 S MELDRUM STREET City of / �ftCottins `�` 7. Culverts N; a . Size N'A • Type N,A • Invert Elevations N" • Headwalls or Wing Walls 8. Sub -Drains • Size • Type (Perforated/Solid) • Cover • Backfill • Geo-Textile Liners • Clean -Outs NOTE: RETAINING WALL SUBDRAIN INSTALL BUT NOT VERIFIED. 9. Curb Cuts OK • Size OK • Tie-in to Swale, Pipe or other appurtenances 10. Common Open Spaces OK • Overall grading contours of open spaces OK • Spot elevations adjacent to private lots (property corners) NORTHERN BIG DEAL SUBDIVISION ENGINEERING 4 521 srne.Caurn STaEEr Fort Collins B. Grading certification 1. Certification of Grade Elevations: OK • Minimum Opening Elevations OK . Top of Foundation Elevations OK . Comparison to 100-year Water Service Elevations OK Comparison to Freeboard Elevations and Base Floodplain Elevations — BFE NOTE: BUILDING ELEVATIONS WITHIN TOLERANCE OF DESIGN 2. Verification of Site Grading: OK a Engineer to evaluate site grading compliance with the approved grading plan. OK • As -built elevations are to be redlined onto the approved grading plan sheet showing the as -built spot elevations next to the design spot elevations so compliance can be verified and documented. NOTE: REVS MADE TO PLAN. OWNER UNDERSTANDS REMEDIATION MAY BE NECESSARY. C. Certification of Erosion Control Measures: 1. Permanent BMP Measures: OA' a Permanent Vegetation (no more than 6" bare spots and weeds under control) N,'A 0 Riprap or alternative permanent erosion material • Riprap Bedding • Cut -Off Walls or Channel Drop Structures Cross -Sections • Sediment Basins OK Water quality ponds/Sand Filter/Bio Retention Construction and liners N/A . Permanent Netting Mats or Blankets OK Mulching and Seeding NOTE: WQ POND VOLUME IS DEFICIENT BUT PER ACCEPTED VARIANCE. NORTHERN BIG DEAL SUBDIVISION ENGINEERING 5 621 5 MEIDRUM STREET Fora, ytdins 2. Temporary BMP Measures: WA • Mulching and Seeding NIA . Temporary BMP Measures as shown on Erosion Control Plan NOTE: SITE IS PERMANENTLY STABILIIZED D. Post -Construction Site Cleanup: OK a Construction Debris Clean -Up (In particular debris affecting the drainage) OK a Smoothing of Ruts in all Construction Areas OK Reseeding of all Areas Affected by Construction Activities (Usually enforced by the City's Erosion Control Inspector but the engineer Certifying the site needs to notify the contractor if areas are not seeded) 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 As - Built plans enclosed. Failure to properly disclose all known information could result in the rejection of this certification and prevent the release of any and all Stormwater Utility permit holds on Building Permits and/or Certificates of Occupancy within this development. F. Signature and Stamp by a Colorado Registered Professional Engineer Ryan O. Banning, P.E. `SS/ONA� EN / Colorado PE Ragistrabon No. 44239 NORTHERN BIG DEAL SUBDIVISION ENGINEERING 6 fi21 S MELDRUM STREET ■� NORTHERN ENGINEERING July 14, 2014 Wes Lamarque, P.E. Stormwater Department 281 N.College Ave. Fort Collins, CO 80537 RE: Big Deal Subdivision As -Built Pond Variance Request Dear Mr. Lamarque: Construction of the multi -family building approved for Lot 1, Block 1 of the Big Deal Subdivision is nearly complete. We have been retained to certify the drainage facilities. The pond volume cannot be certified, however, as built due to a deficiency in volume created by incorrect parking lot elevations. The parking lot, containing a large portion of the major storm volume is nearly 2" high in the area of intended ponding. Due to the above listed issue we respectfully request variances to the following sections of the Stormwater Criteria Manual Section H(3), (Section 3.1.3) requiring the combined WQCV and 100-year storage volume for detention ponds. As constructed 53-cf of WQ storage is provided on top of the required 100-year volume of 649-cf for a total pond volume of 702-cf. We propose that 52-cf of the WQCV would be contained within the 100-year storage volume, assuming that the capacity would be for a single storm with sufficient time delay between storms for half of the water quality volume to drain. As constructed, a portion of the 100-year volume will be released at a slower rate than designed, being forced to be released through the water quality plate. This volume is small relative to the 100-year volume and will have a very small impact on the overflow condition; however the pond will overflow slightly before when it was designed to, assuming that the provided water quality volume is fully occupied at the time of a 100-year storm. A small amount of water will be held within small depressions created during re -grading. This is overlain by landscaping rock and will normally not be exposed to air while held for infiltration. 301 N. Howes Street, Suite 100, Fort Collins. CO 80521 1 970.221.4158 1 www.northernengineering.com NORTHERN ENGINEERING We do not anticipate any additional cost or risk to the City or the public health safety and welfare at large due to this variance. The result of this variance is that a higher rate of overflow will be expected to the inlet within the alley behind the property in very large storm events although it should be similar to existing condition. Emergency overflow beyond what would be intercepted assuming an inlet surcharge is expected to route to areas currently receiving similar flow within the alley and follow currently accepted flow pathways. Thank you and please let me know if you have any questions or concerns. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Ryan 0. Banning, P.E. Project Engineer 301 N. Howes Street, Suite 100, Fort Collins, CO 80521 1 970.221.4158 1 www.northernengineering.com • i Pmcrn uM .u.x sm wx� .rrio a dW Moves ooe+wcroto 1 Po. r r0or ,O 2> FEE, L.a,«K auNa mo RaPRi uYasn/MED) Y- �raa=La,. uM ,ar r axm I ,re a rui r• rtvn Pnvbl x rns.IwN Dray / it wr,wJ v� kANAM I DnMe9 1 1 abLLu L.Els,wr. rIM .L DD ,D D.nu+, PAD CROSS SECTION A -A MB CROSS SECTION B-B GRAPHIC SCALE ® NORTH 1. D Io nrw LEGEND gi6SRM1 p}1pMY LYJSNL SrQN SMR IlE N/ YM �'. E Lti5M4 MLLi GR.1! - ParaLD rurtaw —_ osom cw,our muasn mxL — rRaa4n .rEDr acre a amEn ww�D so, runrlDN eYMmc m T nLv.,nx .y FPa wrLas _ .wD ..Im. 1. ..0 m ..*D c. �Ina.'i ...A .I eE ... 1. rvnM P[Ka.nM NOTES i of va oK.w wCY" DP.u. a.II.C-I: V,uMs AM .M A wp Scr ON ➢[Y rs.n-,: t g...0 ; M Mso69+n V M Cpwb rtw I E Ensnw¢ a .Fx anrwwaw Uu w nM ..-. M M4LM NNOKan rMr QMS,wK1W. nE cWAACIACP pf 9M i M9MA,, rOq tannW ra NCEPP10.N0 N CD AN SxxLL M M9 K9F rtl1 rat ML N.wW UiCPQpMC VM1M5 2 tRP PD 1ME Mi rq 1., MLK R.ii soM EADoANm .��.� MYIS OTEA EASrYd,S .M 1 Iµ PMRx Wn Is pY M or, oF IM C(VM KFMLL WTW: FLK L (NYbL51f4) SE L01q 9i[i r[R IUIOYYM[1Oo943. l .M 41M00 bM[ �Y• rRLY.nWD µL OT[It SOR RECORD DRAWING 0.Y[S wC..M L.4➢. «ML V.V, w.._ nuYnmlonu,uomaa caarbo • City of Port Collims. Colorado UTILITY PLAN APPROVAL y Duee et— � 1� B >3� 9i z Q J a 0 z 0 Q c� snag C3.00 Of 11 sheets