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HomeMy WebLinkAboutSite Certifications - 04/01/2015 April 1, 2015 Mr. Dan Mogen City of Fort Collins Storm Water Utility 700 Wood Street Fort Collins,CO 80521 Re: Stormwater infrastructure and Detention Pond Certification for Rigden Farm Filing 6,Phase 2 and Filing 17. Dear Mr. Mogen, We are submitting for your review and approval an overall site certification of the constructed drainage facilities for Rigden Farm Filing 6, Phase 2 and Filing 17. Relevant drainage studies are "Final Drainage and Erosion Control Report Rigden Farm — Filing Six" dated February 8, 2002 and drainage letter titled "Rigden Farm — Filing 17 Drainage" dated April 24, 2013. The stormwater facilities appear to be in general conformance with the approved plans and drainage report. A record survey conducted by Northern Engineering shows the location of the improvements constructed including the proposed drainage facilities during this phase of development. 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 vs. asbuilt spot elevations for each pond. • As-built drawing set noting the variations from the proposed design for the storm system and outlet structures. (Please note that the dates of work on the various sheets are different due to the fact that field and office work were carried out over a 3 month time period). Variations from the design were typical of those found on most construction projects of this nature and had little to no impact on the proposed drainage structures. The WQCV for both ponds was found to be very close to the proposed volumes. Both water quality flow control plates were constructed per plan. Both outlet structures' overall dimensions were built per plan. Invert elevations of the storm pipes varied slightly and as-built inverts are indicated on the record drawing included with this submittal. The variations are small and are not expected to have a negative effect on the anticipated drainage patterns. All pipes maintained positive drainage. J Page 2 of 2 While onsite we also inspected the temporary erosion control measures such as silt fence and inlet protection which all appeared to be in good condition at the time of inspection. Areas of overlot grading were reseeded and had been mulched. In conclusion, based on the record survey from Northern Engineering and our volume calculations based on the same record survey the drainage facilities for Rigden Farm Fiing 6, Phase 2 and Filing 17 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 970-744-4717 or at michael.brake@merrick.com Reviewed By: G+ t' Michael Brake, PE-PLS Project Manager Q:\NOCO\Projects\MSB\3968301\Word\Letters\As-built infrastructure and Pond Certification revised 4-1-2015.doc Dan Mogen From: Michael Brake <Michael.Brake@Merrick.com> Sent: Wednesday, February 18, 2015 8:57 AM To: Dave Pietenpol (dpietenpol@comcast.net); Fred Croci (fred@cba-fortcollins.com) Cc: Dan Mogen Subject: Rigden Farm Filing 6 Phase 2 Asbuilts Attachments: Sheet 114 Rigden Farm Filing 6 Utility Plans.pdf; FullSizeRender jpg Dave, Dan has reviewed the plans and performed his field inspection. There are several items that Dave Huber and myself need to address before acceptance and the items are as follows: 1. Update the certification letter addressing the different dates on the various plans submitted. 2. Update sheet 133 with revised field elevation data. 3. The slope on the interior area of Water Quality Pond#3 where the rip rap was installed is too steep per City standards. Install fill to flatten the slope. 4. The top of the concrete inlet for Water Quality Pond#3 where the grate hasp install was performed is not acceptable to do the "breaking up" of the concrete. It appears that that the installation of steel material into the concrete has caused the concrete to crumble. This section of concrete need to be repaired and the locking mechanism installed properly so that the grate can be locked. 5. Clean out the debris inside the concrete inlet at Water Quality Pond #3. 6. At the top of the control outlet screen a gap in the new concrete installed exists which will allow debris to enter into the control outlet and cause plugging of the outlet control structure. The gap needs to be repaired and an acceptable fix is to install a steel plate over the gap. 7. Several inlets have concrete splashed over the inlet manhole lid. A cleaning of the steel access lids is required. There are two inlets on William Neal Parkway, one inlet on Cobb Drive and one near the intersection of Percheron and Annika Drive. 8. There is a loose manhole rim and lid on storm sewer manhole 21A which is on a section of storm sewer line discharging into Pond 269 (see attached sheet 114 of the utility plans. This lid needs to be stabilized and not removable either by grouting the rim in place or burying the rim and top of manhole cone in dirt. Once these items are complete Dan will perform a follow up inspection prior to acceptance. Let me know if you have any questions. Regards, L Michael Brake, PE-PLS Project Manager 970-217-4911 cell 970-744-4717 direct michael.brake@merrick.com Engineering I Architecture I Design-Build Surveying I GeoSpatial Solutions ®00 MERRICK' 000 8L COMPANY Please consider the environment before printing this email. This transmission,which may contain confidential information,is for the intended recipient only. Any review,retransmission,dissemination or other use of,or 1 I taking of any action in reliance upon this information by persons or entities other than the intended recipient,is prohibited. If you received this in error,please contact the sender and delete the material from your computer and networks. 2 Dan Mogen From: Michael Brake <Michael.Brake@Merrick.com> Sent: Monday, February 02, 2015 1:28 PM To: Dan Mogen Subject: RE: Rigden Farm Filing 6, Phase 2 Asbuilts Attachments: Rigden Farm Filing 6 Utility Plans interim grading.pdf Follow Up Flag: Follow up Flag Status: Flagged Thanks Dan. We did bury it and they are going to reseed and mulch today or tomorrow. Northern picked up the new asbuilt field shots so I should have those today or early tomorrow. In regards to the ditch behind those lots we did not pick up that Swale as it was to have been constructed with Rigden Farm Filing 6, Phase 1 (Melody Homes). See attached temporary grading plans that were approved so that phase 1 could be constructed. It shows that Swale as part of their construction so they should have provided asbuilts for that work. JR was not part of that project once it went under construction. I did not inspect that area so I am not sure what it looks like today. Michael Brake, PE-PLS Project Manager 970-217-4911 cell 970-744-4717 direct michael.brake@merrirk.com Engineering I Architecture I Design-Build I Surveying I GeoSpatial Solutions 000 &. COMPANY From: Dan Mogen fmailto:dmogen@fcgov.com] Sent: Monday, February 02, 2015 12:05 PM To: Michael Brake Cc: Fred Croci (fred@cba-fortcollins.com); Dave Pietenpol (dpietenpol@comcast.net) Subject: RE: Rigden Farm Filing 6, Phase 2 Asbuilts Mike, Thanks for the update on the pond. The rip rap is required to be buried with 6"of cover to be vegetated. I recently received a cert for lot 217 and the certifying engineer stated that the drainage Swale at the rear of the lot, in Tract AE,was not yet installed. Is this work being completed along with the work in the pond? Thanks, Dan Dan Mogen, El,CFM Development Review Engineer Water Utilities Engineering City of Fort Collins (970)224-6192 1 dmogen@fcgov.com From: Michael Brake rmailto:Michael.Brake(cbMerrick.com] Sent: Thursday, January 29, 2015 10:28 AM To: Dan Mogen Cc: Fred Croci (fredCa�cba-fortcollins.com); Dave Pietenpol (dpietenpol(&comcast.net) Subject: Rigden Farm Filing 6, Phase 2 Asbuilts Dan, We have raised the outlet box to the proper height for Water Quality Pond#3. We were inspecting to determine if the spillway rip rap was installed and buried but it appears that none is installed. So we are going to install the rip rap. My questions is can we leave the rip rap exposed or do you require it to be buried? Thanks, Michael Brake, PE-PLS Project Manager 970-217-4911 cell 970-744-4717 direct michael.brake@merrick.com Engineering I Architecture I Design-Build Surveying I GeoSpatial Solutions ©0 MERRICK"' 000 & C OMPAPAY Please consider the environment before printing this email. This transmission,which may contain confidential information,is for the intended recipient only. Any review,retransmission,dissemination or other use of,or taking of any action in reliance upon this information by persons or entities other than the intended recipient,is prohibited. If you received this in error,please contact the sender and delete the material from your computer and networks. Please consider the environment before printing this email. This transmission,which may contain confidential information,is for the intended recipient only. Any review,retransmission,dissemination or other use of,or taking of any action in reliance upon this information by persons or entities other than the intended recipient,is prohibited. If you received this in error,please contact the sender and delete the material from your computer and networks. 2 i CONSTRI T N MITS MA CHLINE SEE SHEET 26 N 1 EM o OORV L�9� cws+teucnat urn y�� it 1 �=�ySjW�a�Z l / CON*ACm TO RELOCATE EX7I I f O =W p N- _ I FENCE TO PROPERTY LIME I •L... nn�. m�" ,-F F WATER\WAL)TY ONO 3 OO - J�- ®," P. �goa W X sill o coo _4 90' 4889'� LEGEND (] o o PROPOSED INLET AND PIPE J= p I I� lmAR10�CA0E�5fFTEMPORARY �►,\ 1 - --- -- -- `--'_- - \ \ ,g FLARED ENO SECTION J o o 011N yl SHEET lox 1 \ \ Be PROPOSED INLET LOCATION - EXISTING 5•CONTOUR p I-O O N N 39 / 1 \\\ EP%ISTING I•CUNTWR (Y �N O�.- A \ ROPOSFD 5•CONTOUR ti O --- -- , 1, n \� I' I \ \ \' PROPOSED I'CONTOUR w O j V; -- - 0 32A n v / \ \\ \., --�- CONSTRUCTION OMITS = n z N 0 ip ' ' I / / \\ F F FINISHED FLOOR ELEVATION a 3 12 O z X I' CONSTRUCTION ENTRANCE N U= EEE 666rrtJJ _ - H GO i. ,i? - .._.Wig-, - - I r �• SILT FENCE 9p ,t` TT U n v — - $9 - -- - �rp�AUSF o - �7 V90O� 13;11 l `fly Q. 1 486g, - — _4 _ _ / 4'y, �•1 DSO cO• \ 4$88, \ i - --\ - --. _ J/ STRAW BALE 8 FF=09.4LFF=08.I FF>08.1 i' \ '--- A8 " \ Zcg/ 4INLET PROTECTON+02 O 1; \ 488 " W LL SEDIMENT TRAP TYPE L RIP RAP z \-- p\ FROLON PROTFETION u g FINISHED FLOOR ELEVATIONS SHOWN ARE FOR W s 6 .I n INFORMATIONAL PURPOSES ONLY. FINAL FINISHED FLOOR IP ELEVATIONS MAY VARY,BUT THE GENERAL DRAINAGE a W ' r- PATTERNS MUST BE MAINTAINED.rn < M� / � � 2. MULTI-FAMILY LOTS MILL REOIMNE A DETAILED GRADING Q 1 \1n, OA , I • PLAN TO BE SUBMITTED AND APPROVED BY THE CITY / 0 PRIOR TO ISSUANCE OF A BOLDING PERMIT FOR ANY OF /■�/(�//' _ .,-la ALRvwIflr 1\ I //" ' D THESE LOTS iV U I fXQ 94E u/Y/1K ,I ( JI I C7 3. ALL EMBANKMENT SLOPES ARE 4:t UNLESS OTIffRW1SE `�,, _ E,�ur[A7 AYR M��%• ' I / / NOTED. 15.0 � JA:W Ap srat�ifT 1, 11 / 4. HIGH POINTS AND ROW ARROWS ARE SHOWN TO DE➢IC7 DRAINAGE PATTERNS ON INDIVIDUAL LOTS AT THE 1 / TIME THE CONTRACTOR SUBMITS LOT CERTIFICATION. THE I I D'1tST11� L ■ / ENGINEER WILL VERIFY Tiff nmsHED FLOOR ELEVATION AND SEE w OCTAL AgL iRAP 1NS I THAT EACH INDIVIDUAL LOT IS GRADED PER APPROVED � / CRAOING PLANS. o OI 5. REFER TO DETAIL SHEET t32 FOR EROSION CONTROL NOTES AND DETAILS. - -- I ALL SOILS EXPOSED FOR MORE THAN 30 DAYS SHALL m IP IGD N R 1 1 6.BE SEEDED AND MULCHED. 7. CITY INSPECTORS SHALL INSPECT CONSTRUCTION SITE PRIOR TO ANY CONSTRUCTION ACTIVITIES IN THE CHANNEL L O 1 / AND SHALL MONITOR CONSTRUCTION THERE ON, CITY INSPECTORS SHALL APPROVE EROSION / _ CONTROL METHOD/PROCEDURE FOR ALL CROSSINGS OF THE MRTYL 1E E E DETAIL ON CHANNEL PRIOR TO NP ENENTAT,ON.DISTURBED AREAS BARRICADE 102 SEE N'ON \ SHALL BE RESTORED AND REVEGETATED TO MATCH ORIGINAL 11 �✓ / - _ — — PRO D Y E W CONDITIONS, T ON RESTORED/PLANTINGS IN THEO E R/ FA 1 CHANNEL AND ALL DISTURBED AREAS ARE TO BE { , C N .' •/ -- \- RE-CERTIFIED. CONTRACTOR IS TO MINIMIZE DISTURBANCE M 1 r7N GALXNCFWVAH=WAmE D I I �� \, IN THE CHANNEL 1 I " \\ 1 d CONSTRUCTION FENCING SHALL BE PLACED ALONG THE ( \ CONSTRUCTION OUTS ONE AS SHOWN ALONG THE 16.3 I I TSA f► �.� IN F007NNIS REGIONAL CHANNEL u n TEw ..IX a� / �jryEEy p ^ED 1 9. SEE SHLL75 46 A 47 OF DRAKE ZEGLER PLAN SET Z • 9 CLJ ��l � \ , ' FOR EROSION CONTROL ALONG ZIEGLER ROAD. \J, d' ID ALL CHANCES TO THE APPROVED EROSION CONTROL > . \ ��� V• AN 1 r / PL DUE TO CONSTURCTION PHASING SHALL BE ¢ CIDAPPROVED BY CITY NSPECTCRS PRIOR TO IMPLEMENTATION C N r CO ,•. \ I , IT.CONSTRUCTION F04CNC SHALL BE PLACED ALONG THE CONSTRUCTION LIMITS LINE AS SHOWN ALONG THE room I` �� ,\` 1 , '.' REGIONAL CHANNELCP O ED U OER THE DIRECT ARLt9 ERDN OF JJ 1 00 OD PRf rp (A If I \ \ \ \ l I SA11r TWE L- - // sulo X SHMO Q a E I;KL09K E D S EE Ipc i ` \ ' Z Q A \ N a o L 1 �]Et tT[T�a > ~ / , 1i Z City of Fort Collins. Colorodo ( Z LL% 1 UT9JTY APPROYAL MATCHLINE. SEE SHEET 30A 1 I APPRO Eo - .�� �f Q 0 0 a n Cit,E` - Dole LL Z BURY WIN NATURAL Sal VARIES CHECKED BY: hl► O 6- A REVEGETATE HOUSE 2% min HOUSE Way A Worte.atw UtNty 6/N W w (/) 1 _ m6. z+c O TYPE L TNPRAP CHECKED BY:QT.UlKE o n.L t& In F- r a-9 E $Ta m.at• uNN.H, pat• u' ? I J ? D '> - CNffp�p BY: P �t 2_ GRANULAR eEnaNG SIDE LOT CROSS SECTION (TYP.) TYPEE IT ane•R•otWm ole NTS 0100 IT 133X-2.39 CFS(MAIL 50 25 0 50 Too CHECKED BY: iYPE L R1PRAacrrlldl SIDE n•W E LOT AND OFF SITE FLOWS) POk Eay Date SHEET 29A OF 142 7 - - s-7.'S7[ D-o.SS SCALE: E- =50•NORR. CHECKED BY: oat. JOB NO. 9164.12 s,eel a.p..a...Jo..Ma,Oa:AWB 4s�C4<Fat Ci�NAf�Pami l�,.a.4i,M.,nAT..av 201 2, ,N4ti�,l�a�tl.ardo"A. 016E}Nt Na. Fat CaN"vOD■SZIIM - MATCHLINE SEE SHEET 29A z FF=18.2 1 t I / \. WNfW2Kn 1 SV nWW yZ ! 1\ r(3T 321 34y I Iptit F"yW`aalzla�eocx- z anon W� oT FF=n.e i i I t / / KEYWAP a U" M - ---- I J/ ' 0 0 0: FF=16.3 N A ' �O C141 cr co STD — — —_ 1 — -- / ro .�a 30 25 o so Too w o S 1ri o, rc WE n Z rn 1 ' 0' o. 83 OWa I bpgg SC&E- 1'-30' n U0, 1 l 373 I , I C V 1 I R ' I.�D NO F-CL f 343 I I FF=15.6 I io ' FF=16.4 I I Ca /�^ I -�--� -^s PROPOSED MIET AND PIPE $ �9 ' RNtm[ID SECTION ---- ' - - I ' 03 iI . PROPOSED NET LOCATION V 8 1 ( - - - E.5194 S'CONTOUR Z 1 - - - ---- 1- I - --- - IDo � ' ODSTNG 1'CONTOUR 344 l I W FF�45.3 � �i CONTOUR FF-15.5 1 1 1 I - PRaPo�Y z $ 7 PROPOSED r CONTCONTOURNta FF rtw1`os1D 1•-YOUR Z5°"' g COISTRUCD01 ENTRANCE NZ ,s I , 341 1 325 "Ai i SILT FENCE I I I FF=14.9 1 I I V �►'11 i!< m I FF=15.6 1 I O STRAW BaE NET PROTECTION 7 i � SEDIMENT NAP NOTIM, 0 TYPE IL RAP I 3� I I I 72� i �9J• I. FINISHED FLOOR ELEVATIONS SHOWN ARE FOR 1 Fh-14.2 I 4 I ELEVATIONS MAY VARY.BUT THE GENERAL DRAINAGE 1 INFORMAPONK PURPOSES ONLY. FINK FINISHED ROOK FF=15.2 I 1 I X 6g2, _ I / _ .. PATTERNS MUST BE MAINTAINED. NF ��Q�. / ` 2. ALL EMBANKMENT SLOPES ARE 4.1 UNLESS OTHERWISE ` _ r - NOTED. 3. HOCH POINTS AND FLOW ARROWS ARE SOWN TD DEPICT >m PATTERNS ON INDIVIDUAL LOTS AT THE THE THE \ 327 CONTRACTOR SUBMITS LOT CERnnCAPON. THE ENGINEER FF=14 2 .�I 7T F� \ \ '\ WILL DI VERILY THE GRADENISHED FLOOR APPROVED AND G PLAINS EACH INDIVIDUAL LOT IS GRADED PER APPROVED GRADING PLANS. 1 FF=14.6 \ 8 9 4. REFER TD DETAIL SHEET 132 FOR EROSION CONTROL NOTES AND DETAILS. \ '^ p �J \ _ s. ALL AND MULCHED FOR MORE THAN 30 DAYS SHALL OC SEEDED AND WLCNED. O 17 \\ \\ EROSION CONTROL ALONG ZEGLER R QER PLAN SET FOR ROAD a94- LT I VARIES 29 � r tJ• / IS xr.SHEET 29A. �Y SEE DETAIL ON Op 0100 K 1337E-2.39 CFS(MAX i I --_ / 337 ♦ \ \ 00 - -- - SIDE LOT AND OFF SITE FLOWS) i FF=14.S \ iM01MCF fl rff4 D-0.53' \ \ own� - � OL SIDE LOT CROSS SECTION (TYP.) t 1NTS. PREPARED UNDER THE DIRECT sRE7Aa s OF > m / \�� \ m m ^Lv x > `^ u czi I FF=14.3 FF=15.4 QQ\ I 4 LS• \ " \ `I 6 aaM>-EA.sEA 'a-.. l , I FECEPnaV AGI 2000"-2 M 6E MC14D.1,A L.aw X T OAE BY SFPA A 1F OCaA*Nr Q 1329 9 \ J -"- 2 v \\\ -L J C¢ FF-09. S I AG IL w SHEET 102 70 ZJ w w -__-_ City of Fort Collins. Colorado I O Z (n b' -Y coos EA r I I n»v-Emus :nir r J --� \\\\ -- I I _ - l I �ww o v J�'-; - - \ \� \ �� ma vP APPRO UTILITY PLAN AP PRO AL /�'O� O O = Cl- _�� Ao_ Pro• _.. _-. \ -ACS' _.. -�m�av-q cAf MMV .2pAv A CHECKED BY: wnls NA Z 0: - ---- s E laJ (n dEPCEMCY OVERFLOW SPRIY IM I CHECKED BY: 0.Uev(l fiA.LD� Z (SEE SHEET 31 FORNFL DETAIL) RIDGE P.U.D. I STONE RIDGE -P.U.D. • -' '°" w THIRD FILING i FOURTH rILING 4 0" � ' '• CHECKED BY: 4 Porns a Revalion DUN• - -- ---� I CHECKED BY: i T TRACT D/� -- _ -7� �__-____-7_ TRACT A STONE RIDGE P.I.I.D. 1,•/kF•yNa �— SHEET30A of 142 - CHECKED BY: DoN• JOBNO. 9164.12 -moflfdll wpy wdowbAtl oe Ow-EI-301)!geC.y ll Man Ca�uu WAlic RmaB NdIM1e:Yp/hiryloa.kpv.mm artltimlukmm�maafluJemY pl-s emus® qq! 28 NaN CaOep ianCaR�CO B032 USn Fort Collins COMMERCIAL,MULTI-FAMILY AND SUBDIVISION CERTIFICATION FORM&CHECKLIST (Overall Site Drainage) (Project Name) / ? '�o (Date) (For Commercial or Multi-family,please list any applicable building permit numbers) 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: A.Detention Drainage Facilities,and Common Open Spaces 1. Pond Certification -- Provide Topographic Records(grading certification with as—built spot elevations)and Volume Verification Calculations. Show both the proposed and as-built elevations on the same plan sheet. -- Provide Pond Cross-Sections and Spot Elevations(especially @ Pond Embankment and Pond Flow Line) — Positive Fall to Pan(if applicable) -- General Pond Grading including all Side-Slopes ---J Invert Elevation — Forebay Construction and Elevation p Spillway Weir(Location,Elevation,Height,Opening Width) ' — Placement and size of riprap or alternative permanent erosion control measures Orifice Plate and/or Water Quality Outlet Structure Installation 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 12/12/2014 Revision - Page I of 5 Fort Gottins 2. Swales ( A Location(are they within easement?) Dimension and Cross-Section Verification ongitudinal Slopes and Side-Slopes — Spot Elevations — Permanent Erosion Control Measures(drop structures,riprap,lining) - Tie-in to Storm Lines,Pans,Curbs,or other appurtenances - Required Minimum Freeboard,Provided Freeboard -- Landscaping Infringement on Flow Line? 3. Pi gs �F Size and Type Slopes(As-Built and comparison to 0.4% Minimum) — Pipe Capacity Calculations(if slopes are significantly altered from design) `= Invert Elevations - Installation and Backfill -- Cover Encasement and Clearance from other nearby utility lines — Joints Type and construction 4. Concrete Pan Channels ✓Size -4-11ope �oss Section U,L T��z AA� �Thic kkness —e Elevations 12/12/2014 Revision- Page 2 of 5 Form of S. Inlets -Size and Type Size of Opening(or name of Standard Detail used) Grate Elevation Invert Elevation Box Size 8U eT�.� PG4.�1 b. Street Cross-Pans -- Size Type — Grade -- Elevations - Cross-Sectional Depth — Tie-in to Curb and Gutter 7. Culverts A IA Size -- Type -- Invert Elevations -- Headwalls or Wing Walls 8. Sub-Drains /,,/ /A -- Size — Type(Perforated/Solid) — Cover --- Backfill 12/12/2014 Revision Page 3 of 5 of Fort Collins - Geo-Textile Liners --- Clean-Outs 9. Curb Cuts /J 1,a, — Size -- Tie-in to Swale,Pipe or other appurtenances 10. Common Open Spaces Overall grading contours of open spaces — Spot elevations adjacent to private lots(property corners) B.Low Impact Development(LID)Certification J' /-,? 1. LID Technique Specific Checklists(see attached) — Permeable Interlocking Concrete Pavers(complete if technique utilized on site) --- Bioretention Cells(complete if technique utilized on site) C. Grading Certification JLf f 114_ 1. Certification of Grade Elevations — Minimum Opening Elevations -- Top of Foundation Elevations — Comparison to 100-year Water Service Elevations -- Comparison to Freeboard Elevations and Base Floodplain Elevations—BFE 2. Verification of Site Gradine �ngineer to evaluate site grading compliance with the approved grading plan. 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. 12/12/2014 Revision--Page 4 of 5 of Fort Colllns D.Post-Construction Site Cleanup 1. Permanent BMP Measures Construction Debris Clean-Up(In particular debris affecting the drainage) -`= Smoothing of Ruts in all Construction Areas --` 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 Engineer's contact information: (Name) (Company Name) (Email address) (Company Address) (Telephone number) F aND P.V C PE STAMP 12/12/2014 Revision--Page 5 of 5 Water Quality Ponds Along Foothills Regoinal Channel Asbuilt Detention Pond -Stage/Storage LOCATION: Rigden 2 PROJECT NO: COMPUTATIONS BY: M.Brake SUBMITTED BY: Merrick and Company DATE: 2/5/2015 V=1/3d(A+B+sgrt(A'B)) where V=volume between contours,ft3 d=depth between contours,ft A=surface area of contour Water Quality Pond 1 Surface Incremental Total St-ge Area Storage Stor e (ft) (ft�) (ac-ft) c-ft) Pond inv.- 4906.49 0 4907 ?55 0.00 _ 0.00 4908 1,3 0. 2 0.02 Pipe Inv- 4908.2 11582 .01 0.02 Elev of WQ orifice- 4908.49 1,986 0.01 0.04 4909 2,696 03 0.06 WQCV- 4909.90 4,0019 0. 0.13 4910 4,222 0.01 0.14 Top of WQ structure- 4910.5 5,082 0.05 0.20 491 5,941 0.12 0.26 top of berm- 2 7,840 0.16 0. Water Quality Pond 2 Surface Incremental Total ge Area Storage Stor e (ft (ft') (ac-ft) c-ft) Pond inv.- 4903 0 4904 37 0.00 0.00 Pipe Inv- 4905 9 9161 0.02 Elev of WQ orifice- 4905.3 11199 0.01 0.02 4906 1,828 0.03 0.05 WQCV- 4906.60 2,637 3 0.08 4907 ;176 0.0 0.10 Top of WQ structure- 4907.3 3,741 0.02 0.13 490 5,059 0.09 0.20 top of berm- 4 09 61569 0.13 Water Quality Pond 3-ASBUILT Surface Incremental Total Required Stage Area Storage Storage Volume (ft) (ft`) (ac-ft) (ac-ft) (ac-ft) Pipe Inv- 4880 0 0.00 0.00 Pond inv.- 4880 0 0.00 0.00 4881 1,633 0.01 0.01 4882 6,122 0.08 0.10 4883 9,836 0.18 0.28 Top WQ Struct/WQCV- 4883.90 12,755 0.23 0.51 0.53 4884 12,932 0.03 0.54 spillway 4884.5 13,762 0.15 0.69 39164wq-RI I_ASBUILT Pond 269 Asbuilt Stormwater Quality Pond STAGE-STORAG-DISCHARGE CURVE LOCATION: Rigden Farm-Filing Six PROJECT NO: COMPUTATIONS BY: M.Brake SUBMITTED BY: Merrick and Company DATE: 2/5/2015 Stage Surface Incremental Det.Volume h Area Storage storage (ft) (ft2) ac-ft ac-ft invert- 4870.00 38,461 0.00 0.00 4871.00 43,576 0.00 0.00 4872.00 48,717 0.00 0.00 4873.00 53,964 0.00 0.00 4874.00 59,417 0.00 0.00 4875.00 70,085 0.00 0.00 4876.00 85,710 0.00 0.00 4877.00 99,451 0.00 0.00 Normal WSEL- 4878.00 113,629 0.00 0.00 WQ WSEL- 4879.20 135,289 3.42 0.00 4880.00 144,912 2.57 2.57 4880.20 147,421 0.67 3.24 4880.30 148,780 0.34 3.58 4880.40 150,260 0.34 3.93 100-yr WSEL- 4880.50 151,946 0.35 4.27 4881.40 169,882 3.32 7.60 4882.00 182,791 2.43 10.03 Spill Elev. - 4882.16 188,108 0.68 1 10.71 Detention Volume is not required per approved drainage study.