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HomeMy WebLinkAboutSite Certifications - 05/20/2004748 Whalers Way, Bldg, D Fort Collins, CO 80525 970.226.0557 metro 303.595.9103 fax 970.226.0204 info@tstinc.com www.tstinc.com TST, INC. CONSULTING ENGINEERS Mr. Basil Hamdan City Of Fort Collins Stormwater Utility Department P.O. Box 580 Fort Collins, Co 80522-0580 Re: Respite Care Center Stormwater Certification Project No.: 0739.0100.00 Dear Mr. Hamdan: May 20, 2004 Please find enclosed our pond certification for the as-built condition of the detention pond at the Respite Care Center as of May 19, 2004. TST Inc. surveyed the finished floor elevations of the building, curb and gutter flowlines, storm sewer inverts and the detention pond as installed by the contractors. The as-built 100-year water surface elevation is 4909.68. Since our design elevation was 4909.25, the orifice plate opening, spillway and freeboard issuel> were examined to ascertain the impact. The difference in water elevations was found to have no significant impact on the orifice opening release rate. The pond spillway elevation was adjusted and the spillway widened. The pond spillway adjustment has been completed by the contractor per the new design. Calculations for both the orifice opening and spillway can be found with the attachments, as well as a table showing both the design and as-built pond volume and elevation information. The limiting factor for the pond's freeboard is the curb cut opening from the driveway. The flowline elevation of the curb cut is 4910.27, which is 0.6' above the 100-year water surface elevation of the pond. In the event that the pond outlet did not function or became plugged, or in a 100-year or greater storm event, the spillway would release water from the pond and prevent the water from backing up and releasing from the curb cut. Also, the finished floor elevation of the basement is 4911.99, which is approximately one foot above the top of the pond berm, providing an additional safety factor. Please contact me if you have any questions. Sincerely, Dave B. Lindsay, PE SMS/DBUrmg Enclosure(s) S 0 TST, INC. Consulting Engineers :1 , CLIENT /J.L e._,e_AA.(i. \o JOB NO._).,...._,_~.,,,_, ,-+-q_-~/-"'=·-""_ .. ---- • t PROJECT \(, Q-<:.p l""'-<-c(J r::;.,.... Ce. v~ CALCULATIONS FOR __,( ...... )'--'--('-"-' ___.__·, C:..,,,.__,._e-. _._R-4-ll,.;:_:i-............ P ...,.C=·-..:P'-'ll..:...J\::....=....! 0 "-"-"l~----'-_...:. ,... •\e-, ~ , .. , r) MADE BY_~>'~'~->~-DATE .) ~ j 5,-l, DATE SHEET I OF I CHECKED BY ___ _ rr ,. .c ) ~ . c::: A .. ,-;. o o ----\ /.A ) '{\.R_ .. '{ ) ....:"-'/sl) fl --"" ~ .c 0 •. ("',.>'-! >.," /f ' 9{ ' . f ... \ 'i ti ~\ ~fe.~ .c... J~ ·IJ' l. )s <" ll. 4 lv « II tl()+ ., (. { If 1 --------~~------------------ s 0 TST, INC. Consulting Eng ineers A ) • CLIENT_--'--'r-rve.__..1 -'"--1"' 1~;-::-f\ .:;.:..r, .:.:c'.....,'=--------------JOB NO.--''-----'--'--'------=-=---- I MADE BY ____c;-"-'------e:::.....-DATE ____ CHECK ED BY ___ DATE SHEET --!:---l _ OF ___,_/ __ _ L-c~ C-t..,\-\"J'~ --; ..... () c-rS ll,6)( 0 ?i+t) 31 ~ -1\.0 t+ w~~ G-;. ~;ffr.vC<.-~ .P.foiv r~-k...( ~~) C, ... :;. Cy-e.s+ e,,e_.f+ic;a.-~+-(t., ) 1,.-:, c.,~~+ Le""f{~ { ~ ) tt " V\.Q. v-\j •s,ri 11 w j · ·' ~ , -H.o' ·---~ De s i g n B a s i n = A r e a = A3 , A4 , AS , A6 • C= Fr e q uen c y = Re l e a s e = V = 11 3 *d * (A 1 + A 2 +s qr t ( A 1 *A2 ) ) Po n d St a o e In cr e m e n t (d l 0 0 49 0 8 1 49 0 9 1 49 1 0 1 Re q u i r e d S1 o r a g e Vo l u m e = I WS El e v is Ab o v e St a g e Lo w e r St a g e Vo l u m e ( f t ' 3 ) = Up p e r St a g e Vo l u m e (f ! A 3 ) = Lo w e r St a g e El e v a t i o n {f t ) = Up p e r St a g e El e v a t i o n (f t ) = TS T , IN C . CO N S U L T I N G EN G I N E E R S 1.66 l a c M3 100 ly r 1.34 cf s Ar e a (f ! A 2 ) Vo l u m e (f t ' 3 l 0 0 42 8 2 14 2 6 65 5 4 53 7 2 94 2 5 79 3 8 97 3 8 l ft ' 3 3 Pic k St a g e 14 2 6 Ac t u a l WS E L = 14 7 3 7 Fr e e b o a r d = 49 0 8 49 1 0 To t a l Vo l u m e (f t ' 3 ) 0 14 2 6 67 9 8 14 7 3 7 I 49 0 9 . 2 5 ,~ 1.75 Ta b l e 1 De t e n t i o n Po n d 'A ' De s i g n / A s - B u il t Co m p a r i s o n As - B u i lt Ba s i n = Ar e a = A3 , A4 , AS , A6 • Vo l u m e (a c - f t ) 0.00 0.03 0.16 0.3 4 C = Fr e que ncy = Re l e a s e = V = 1/ 3 * d * ( A 1 + A 2 + s q r t ( A 1 * A 2 ) ) Po n d St a g e In cr e m e nt (d ) 0 0 49 0 8 1 49 0 9 1 49 1 0 1 Re q u i r e d St o r a g e Vo l u m e = I WS El e v is Ab o v e St a g e Lo w e r St a g e Vol u me (f ! A 3 ) = Up p e r St a g e Vo l u m e (f ! A 3 ) = Lo w e r St a g e El e v a t i o n (f t ) = Up p e r St a g e El e v a t i o n {f t ) = Pa g e 1 of 1 1.66 1a c M3 10 0 l yr 1. 3 4 cf s Ar e a (f ! A 2 ) Vo l u m e ( f t ' 3 ) 0 0 17 2 3 57 4 59 7 9 36 3 4 86 7 1 72 7 6 97 3 8 11 1 ' 3 3 Pic k St a g e 57 4 ! Ac t u a l WS E L = 11 4 8 3 I Fr e e b o a r d = 49 0 8 49 1 0 To t a l Vo l u m e (f ! A 3 l 0 57 4 42 0 7 11 4 8 3 I 49 0 9 . 6 8 1.32 ,~ Vo l u m e (a c - f t l 0.00 0.01 0.10 0.26 05 / 1 2 / 0 4 Hy d r o m a s _ 7 3 9 - 1 0 0 jF F = 2 1 . 0 0 ! ·. ~ / ii i 9, 't ' . > ~ C o n o u ~ ~ - 71 . . t " ' : : . . "1 . : 1 D ,, . , . . . . . . . . . . . , FA X : 17 0 - 2 : z l - 0 2 0 4 ~ .. . . . . . . . , .. . . . . . . . / ' \' - - . . __ -- . . . .. . . . . _ I -·~t i·· ~ 17 . 1 ~- .· ~ ~ ~ .. 11 . > 9 ',ft~ \ \ \ -' , i; r " ' . · j, ., ~ .. . . . ~f ' ) ~ •· . · . ' .. . . . . . / / / .. ~ / / ,: I, ~ ' L , DRAINAGE CERTIFICATION FORM Plea£e fill out all applicable items in this certification form for single family, multi·-family and commercial properties. Write "0K 11 for items checked or actual number checked in field . m~e "N/A 11 for items that are not applicable to the property tha.t is being certified. A. Drainage facilities certification 1. Pond Certification -volume veri.fication a. topographic records and volume b. cross-sections and spot elevation.s -p9sitive fall to pan ' -side slopes -invert elevation -spillway elevatio~ -placement and size of .riprap :.. -side slopes -grading -orifice plate installation and size -compaction of berm -structural integrity of pond 2 . · Swa1es ,-location (are they within easement) ~dimensions and cross-section verification -longitudinal slopes and side slopes -spot elevations 0/( 0/( ,, ' •/ t'-·<- Ii~ --.- i -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. Pioes -size and type ~slopes (as-built and comparison to ·minimum 0.4% slope) -pipe capacity calculations if slopes are significantly altered -invert elev~tions -installation and backfill material -cover -encasement and clearance from ·other util~ty lines close by -joints 4. Concrete Pan Channels -size -slope -super elevation -cross-section -thickness -elevations ;A . J[_ 5. Inlets -size ·and type -size of opening (or name of standard used) -grate elevation -invert elevation -box size 6. Cross pans -size -type -grade -eievation -cross-sec~ional d~pth -tie-in to curb and gutter 7. Culverts -size -type -invert elevation -headwalls 8 • Underdrains -size -type -cover -backfill -geotextiles ( I· --.- l -+­ _,_1 _ i Yi_ ___._ ! _I _ • -cleanouts 9. Curb cuts -size -tie in to swale, pipe, etc .... B. Certification of Grade Elevations Adjacent to Drainage Facilities: -minimum opening elevations -top of foundation elevations -comparison to ·100 year WSEL's (Freeboard requirements and floodplain issues) C. Certifi~ation of Erosion Control Measures: 1. Permanent Measures: -Permanent ve~eta.tion (6" bare spots -and weeds under control) -riprap -riprap bedding -drop sections -sediment basins/water qu~lity ponds -netting mats/blankets -mulching . J(L ( o_K, -"'\ 0 /';- \O K .' ..._. ' , _ _ ,_ . . 2. Temporary Measures: -mulching -inlet filter installation -check bale dams -seeding and temporary vegetation -silt fence D. Site Cleanup After Construction -construction clean up -s·moothing of ruts -reseeding E. Statement of Compliance 0/(. I +I This certification is signed and stamped and by signing this form the engineer (s) attest.s that to the best , of his knowledge the ·~s :..·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 anp./or Certificates of .Occupancy. F. Signature and Stamp by a Colorado Engineer. 748 Whalers Way, Bldg, D Fort Collins, CO 80525 970.226.0557 metro 303.595.9103 fax 970.226.0204 info@tscinc.com www.tstinc.com TST, INC. CONSUL TING ENGINEERS June 8, 2004 Mr. Basil Hamdan City Of Fort Collins Stormwater Utility Department P.O. Box 580 Fort Collins, Co 80522-0580 Re: Respite Care Center Detention Pond Certification Project No.: 0739. 0100. 00 Dear Mr. Hamdan: Please find enclosed our pond certification for the as-built condition of the detention pond at the Respite Care Center as of June 7, 2004. The contractor made adjustments to the pond grading per the City's request. The bottom of the pond was re-graded to flow to the outlet structure. The bottom of the pond now slopes from the outlet of ST-1 to the outlet structure at 1%. West of the ST-1 outlet the pond slopes from the north toe to the south toe and then to the outlet structure. The area around the pond outlet was flared out to better drain away from the outlet pipe to the wetland area south of the site. TST Inc. surveyed the detention pond as adjusted by the contractor on June 7, 2004. A variance is being requested for the pond bottom slope to be less than 2%, with no trickle pan. The pond bottom is to be seeded with a wetland grass mixture per the City's request. Please contact me if you have any questions. Sincerely, TST INC. CONSUL ?t{ .En SMS/DBUsjk II 748 Whalers Way, Bldg, D Fort Coll ins, CO 80525 970.226 .0557 metro 303 .595 .9103 fax 970.226 .0204 info@tstinc .com www.tstinc .com STORMWATE R TST, INC. CONSUL TING ENGINEERS RECEIVED AUG 1 !2004 !)S . Mr. Jay C. Barber City Of Fort Collins Stormwater Utility Department P.O. Box 580 Fort Collins, Co 80522-0580 Re : Respite Care Center Detention Pond Certification Project No.: 0739.0100.00 Dear Mr. Barber: August 17, 2004 Please find enclosed our pond certification for the as-built condition of the detention pond at the Respite Care Center as of August 5, 2004. The contractor made adjustments to the pond grading per the City's request. The bottom of the pond was re-graded to flow to the outlet structure. The installation of a concrete trickle pan from the inlet to the outlet was also installed to convey the small nuisance flow . West of the ST-1 outlet the pond slopes from the north toe to the south toe and then to the outlet structure. The area around the pond outlet was flared out to better drain away from the outlet pipe to the wetland area south of the site. Also the riprap was exposed per direction of Glen S. to give the water a place to percolate into the ground . TST Inc. surveyed the detention pond as adjusted by the contractor on August 5, 2004. The Pond has also landscaped and seeded. Please contact me if you have any questions. Sincerely , TST, INC. CONSUL TING ENGINEERS ichardA.2 ~ SMS/DBUsjk II ii i ~= - - - .. -~ . =~ RE S P I T E CA R E C E N T E R PR O P O S E D DE T E N T I O N PO N D TR I C K L E PA N 10 0 ' S [ 1 M O C / I 'J l t SN I T N I Y S D E R ~T C \ TI E PR O P O S E D PA N TO EX I S T I N G 15 " F L A R E D EN D SE C T I O N PO i i ) OU 1 l . £ T 15 " A D S • 22 1.f. w / J U (S E [ DE T A I L SH E E T I ) 12 ' • 11 . 7 ' T ' l l ' f : L - P l > l l (S E [ DE T A I i . SH E E T I) D£ m m O N PO i i ) 'A ' ,o o - , . . W9 f l . • - . a 5 .. x1 1 .oo ~ 15 14 .