The URL can be used to link to this page

Home My WebLink AboutPINEWOOD PATIO HOMES PUD PRELIMINARY AND FINAL - 4 92A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTSTORM. DRAINAGE AND EROSION CONTROL REPORT FOR PATIO HOMES AT PINEWOOD P.U.D. A REPLAT OF PART OF PINEWOOD P.U.D. Prepared for SUNBELT REAL PROPERTIES 1985, LTD. February 3, 1992 STEWART & ASSOCIATES, INC. 214 North Howes Street Fort Collins, Colorado 80521 CIMPUTATIONS . Stewart & Assoclates, Inc. 214 N. Howes St.•:,Ft. Collins, CO 80521 (303) 482-9331 By: Pl)z Date 2 3 Client: 5vhb e d KOA1 2:0per diej Sheet No. 8 of Chkd By: Date Project: Pa l a /40e-es ok4- �i�e✓ova uj> Subject 717/a L OeLg4ien lloIuMe and fZeleare Na{_ RAINFALL PERFORMANCE STANDARD EVALUATION -------- ---- ----------------------------------------------, PROJECT: STANDARD FORM A COMPLETED BY: Ehl 1::ZLIbirs0r ------- --------- ------------- --DATE_-Z 34_z--I DEVELOPED ERODIBILITY Asb Lsb Ssb Lb I Sb PS SUBBASIN I---ZONE----� (ac) (ft) -(e)-- (feet) I (ro)--(q)-- %7.aL ! MOvmo-rE Z. 06 s1I3S0 i l 3SU i -%%Z 7 )7F 1 _ --------------------------------------------------------------------- DI/SF-A:1989 $_18 DESIGN CRiTERI.. JA.'IliaRY 1991 EFFECTIVENESS CALCULATIONS --------------------------------------------------------------- PROJECT: STANDARD FORM B COMPLETED BY: _ Elzi/ Rdbinso*) DATE: Z s 2 Erosion Control C-Factor P-Factor Method --sor---t. Value Value Comment I3----E ------------- ----------0 l--:a-v - -------------------- y.oo sideyGrds GRF+vEL FILTER /-au 49-00 57R,'c4L✓ 014LE 6/4991tR /.o0 0.00 KoAb5 wlq-(,){S 0.01 1.061 FOvA1 /aT/0A,,s 0.01 I.00 S79AwMVLC14 YSEW /.Ov, 0.01; in oleien4on pono/s MAJOR BASIN r7,4L S)TE SUB BASIN I AREA (Ac) z.06 CALCULATIONS ------------------------------------- PvM� area fvvrid a Plors- � = /, 3j 1¢---- s}r-aw rovl6h sral in yonjs dare A rov nd - 0. SL 14C V4--d C (O.U� x1,31�+(o`.OGxO.l9�t(IU�xO.sG) 2.0C 0, 28 k/At I' .80 FFIB _ l -(0,Z3'xG-&D,xroo = 77, 10,7 --------------- DI/SF-B:1989 TA}ITTI n-, Inn I ---------------------------------------------------) CONSTRUCTION SEQUENCE PROJECT: Pi-3-rio Nnrirs ^T PJnJFwooD. STANDARD FORM C SEQUENCE. FOR 19 7 Z ONLY 'COMPLETED BY: Fl/ TZ DATE: Z Z Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an approved schedule may require submitting a new schedule for approval by the City Engineer. YEAR MONTH ---------------------------- OVERLOT GRADING WIND EROSION CONTROL Soil Roughing.... Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other Foundai-lons� Pv,-A4- RAINFALL EROSION CONTROL STRUCTURAL: Sediment Trap/Basin- Inlet Filters Straw Barriers Silt Fence Barriers Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving Other VEGETATIVE: Permanent Seed Planting Mulching/Sealant Temporary Seed Planting Sod Installation Nettings/Mats/Blankets Other -------------------------------------- ------ STRUCTURES: INSTALLED BY MAINTAINED BY VEGETATION/MULCHING CONTRACTOR DATE SUBMITTED HDI/SF-C:1989 n/ I . I I I ----------------------- APPROVED BY CITY OF FORT COLLINS ON JANi A2 Y 1991 8-20 DESIGN CRITERIA. ::w -:. Wu11 IKrNIt u/fN.a L.Yt [Nvrr or oruua `,�... rr[or IN wsw•- darn Y,A1. • _ b•A. m Li ICt/r. C A.1161 tl Imm'-110 A, All. . n Y yJRr ITYII N� Y -NA. WpI /Mf C//r Ol lr Ca l/{ :, � [ •ri: -e =.n' "" GLASS B BEDDING MAN[ eoe . awl/ CN.blwc w Yr•%[ %n- tl[ RtlA... C!..1 y uel/ � w rrC I C�-•.L c..•.w ..• �•; _� � ANAAA0v,r Lam! STORM SEWER BEDDING DETAIL y ' Mrs ALTERNATE BASE SHALLOW MANHOLE DETAIL NrS. GRADING AM DRAINAGE PLAN SHEET NOTESi 11 SENCHRAM. NORTHEAST BONNET BOLT OF TIRE WYDRAWT AT NORTHWEST CORNER Cr DRAEE ROAD AND STOVER STREET. ELEVATION - 4997.90. II MISTING CONMURS Alm EXISTING SPOT ELEVATIONS ARE FROM THE BRADFORD L. SMITE Aim ASSOCIATES PLAN SET FOR PINEWOOD TOWNHOME P.U.D. DATED JUNE. 19:.13. L EGENO ON/OSeO SmIm SE�•T w/•u.w/ ®— ex/ST/Mi er0% sew(! w/C.rem L.S/N wl«4rr OL.IOr&a et/Lr Le(✓ /r m/a, et/ea fr.re.t LW.VrcS « /Lr OtLYN•O eLLr /r Iwo e v s/Ne —� aENOrLs fX/L%.ae TLOW ~M 4"Sr/N4 eaNTO✓Ls PLAN V/EW OR/FACE O"7'9 f/EA0W,41 NTL i AI wC✓NI raw.".1 �— • 0• I.IYYI MYIO ZAN. W 1 10 If CNNC'r, r0 Ira NP`m v ILdf N /IYN MI NCCWRr CNNCI T N% Im 'Aww b'1rW( CNrCM/ . IC Y" LCCC MLY IS Nr . a• 01I1YMr STANDARD TRENCH DETAIL MI5 ./r-M'C/M<LO[r erve) `fYL'F!•O/IEN/M. /NCNOe l Ts ( N.LON mses.L v.N/ELo r(L ELE✓AT/ON /TTM /s9 /;YLEO HCNOL Lrs I•M/N J MNNw. /'IT p•rLw1 �.. • uwr�.wty u n /M /wLtl / HLOa tECT/ON /-w TR. CROSS CNE/<l• MN M/e • B B µ��►7:Rt�b2�1�1��t.7il�b7�17i1��aL��A� • � li��fl�I�a��5E�'lil■�W�Z�'Zi�� 11��Dz>•Il�u•:LCTR>.JI��a91��`:�� l7RRi��Ra��;� wrr mw 111111� 1� IIIIIIIIIIIIII��IIIIICIIIIIII, V�11111111111111.111111�111111111_IIII�1-1111-11111��1111� 0+00 U+'6U 1reu U+UU U+6U l•ZU S70RM SEWER RELOCATION LINE "A11 STORM SEWER RELOCATION LINE "B" 1 G•AN e/L 0IOO Y.f [ " 1 , error t.•e~ BEET E10RM rroL.J R/rver Tvtef c Ayv r00 'Ise --_qs S VEp S O`! FLOW ry+ +«-OR MO✓NT w-,A, ✓NIN✓M "Are O /�I I^` av ar/rctr ills. /m/re ra rer. oriries. seee Awoer./c TL_Ll/S(/e EMI' __-LNAlON MNrf'J �'` �iC 4T. \ � ♦ sM.a[arv�� INy Tar/ -a ArAAN f0✓ liOM 'i cy.411?� 1\ \\ / 1 N0 I'1 GTO 1,,S(CI TCM i[L/N fir` Re(✓/t04 TCN QILJM"• L,. � � ipv, Y4'•� � STANFORD I SCALE I•. AlT 5. SECT/ON w.I a� Io✓ � 2 j. - __ 4a•Ir.L ? o 0 Fr J tla �1$ rtq/.J ♦ o p0« U a •• lax Y: PINEWOOD P. U.D. GRADING & DRAINAGE PLAN-F 2 ... , STEWART&kSSOCIATES Consulting Engineers and Surveyors February 2, 1992 Ms. Susan D. Hayes Stormwater Utility City of Fort Collins P.O. Box 580 Fort Collins, Colorado 80522 Dear Susan: I am writing to request a variance of the allowable stormwater release rate from the Patio Homes at Pinewood P.U.D. The calculated allowable release rate is 0.60 c.f.s., per the City of Fort Collins Storm Drainage Design Criteria. Our proposed layout and design of the site will have four separate detention pond outlets. These outlets, when sized by the Storm Drainage Design Criteria, are too small to be practical. We propose that the minimum outlet size be 3—inch diameter which, for the four outlets, will allow a total 100—year storm release rate of 1.49 c.f.s. This amount is less than the existing condition 2—year outflow of 1.66 c.f.s. The existing condition 100—year outflow is 6.51 c.f.s. The downstream pipes have adequate capacity to carry the proposed release quantities, and any overflow will go through the parking lots to Stover Street. Thank you for your consideration of this request. Sincerely, Phillip Y Robinson, P.E. .& L.S. Vice President jrr James H. Stewart and Associates. Inc. 214 N. Howes Street P.O. Box 429 Ft. Collins, CO80522 303/482-9331 DRAINAGE AND EROSION CONTROL REPORT PATIO HOMES AT PINEWOOD P.U.D. Patio Homes at Pinewood P.U.D. is a replat of the west one—half of Pinewood P.U.D. Pinewood P.U.D. is a replat of the original plan of Pinewood Townhome P.U.D. Pinewood Townhome P.U.D. was designed by Joseph Roesser in 1979, and the utility lines, curb, and pavement were constructed per this plan. This 1979 plan provided storm drainage detention in the parking lots with outflow through area inlets and pipelines, which emptied into a grass Swale on the east side of Stover Street. There are two drainage basins in the development. The east one is fully developed, and the west, which is Patio Homes at Pinewood P.U.D., has all of the utility lines, curb, and pavement constructed.. There are no residences constructed in the west portion, but there is one 5—car garage existing. This garage was constructed by the Pinewood P.U.D. plans as designed in 1984 by Engineering Professionals. The Pinewood P.U.D. replat of the Pinewood Townhome P.U.D. did not change the grades or locations of the existing curbs and pavement, but it did propose to deepen the west detention pond from a depth of 1.1 feet to a depth of 1.7 feet at the inlet grate. This raised the high water line of the pond from 98.0 to 98.6. The previously mentioned 5—car garage is constructed with a floor elevation of 97.6 which puts it 0.4 feet below the existing overflow elevation of 98.0, and would put it 1.0 feet below the proposed elevation of 98.6. The Engineering Professionals grading plan shows the floor to be above the high water line,. but this plan apparently was not followed when the garage was constructed. Our plan is to raise the garage floor six inches by placing a concrete overlay on the existing slab floor. Also, we propose to keep the pond overflow at elevation 98.0. which would be the same as the raised garage floor. The existing detention pond has a volume of 5600 cubic feet to the overflow elevation of 98.0. This is less than the required detention volume, which we have calculated to be 14892 cubic feet. We propose to provide additional detention volume in three ponding areas on the landscaped portion of the site. The total additional volume of these three ponds is 9315 cubic feet, which will provide a total onsite detention volume of 14915 cubic feet. Sheets 5 and 6 of this report show calculations of the volume and outflow of each new pond. The calculated allowable outflow quantity from each of the three new ponds requires restricted outlet sizes which are too small to be practical. We propose that the restriction size be limited to a minimum size of a 3—inch diameter opening. The outflow quantity from the larger openings is more than the allowable; therefore, we will request a variance of the release rate. The total outflow from the four new restricted outlets will be 1.49 c.f.s. The calculations on sheet 3 of this report show the 2—year and 100—year outflows from the site for historic, existing, and developed conditions. The proposed outflow of 1.49 c.f.s. is less than the existing condition 2—year outflow of 1.66 c.f.s. The 100—year historic outflow was 2.27 c.f.s., and the 100—year existing condition outflow is 6.51 c.f.s. Patio Homes at Pinewood P.U.D. February 2, 1992 Page 2 The 1984 Pinewood P.M. plan called for a 3z"x3" restriction plate to be installed in the existing manhole on the west side of Stover Street. This manhole controls the outlet into the Scotch Pines swale lying east of Stover Street. A restriction of 8"x32" was proposed out of the existing area inlet in the west parking lot. This 8"x32" opening would release 1.8 c.f.s., which is too much. We propose a 3—inch diameter opening which allows a release rate of 0.46 c.f.s. The 31"x3" orfice will be installed in the existing manhole by the Patio Homes at Pinewood P.U.D. project. Also, the 3—inch diameter restriction will be installed in the existing parking lot area inlet, along with the three new restricted outlet ponds. The downstream pipe systems have adequate capacity to carry the restricted flows. The existing 8—inch pipe will receive a maximum of 1.49 c.f.s. from four restricted outflow points, and the flow in the existing 18—inch pipe along the north side of the site will not be changed. Overflow from any of the ponds will go through the parking lots and onto Stover Street. EROSION CONTROL: Patio Homes at Pinewood P.M. will not require overlot grading since the curbs and driveways are existing. The detention ponds will be graded, and the pipes and inlets will be installed. Sediment filters will be placed at the inlets, and straw bales will be placed along the back of the curb on the east property line. The foundations will be excavated and the concrete placed, so there will be no extended periods with bare ground exposed. This site is located in the moderate wind erodibility zone, and the existing curbs and streets and the new foundations will provide sufficient roughening to prevent wind erosion. Attached are plans of the 1984 Pinewood P.U.D. and of the proposed Patio Homes at Pinewood P.U.D. Phillip URobinson, P.E. & L.S. on�Ql Q eeee e0oe QA.�j� e iW 1491 c • • 4502 = y • • f T e � AMPUTATIONS Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 By: OB Date Z 3 Z Client: -5(/1)he# K&-ql PrOi2ar-Leor' Sheet No. 3 of Chkd By: Date Project: Fail 401Ae-S PneLaftj- ?V12 Subject a i,5 4-o 'r i c U Tie rs �7 (- 00 =1 0 i G?iv' �� ct/3 , 2 14- 17— 2 Z7 C- EX r s �-r �g =-' � ,.. � . is � , �,c _ � i- .� � I i s = j 1. b � I ;ill � �. I i. � �.. �II�I.,_) 0.: q ;T6 7i 4 0 4-1 /+ 4 C J 17C4 5 Lit- VA aft Ir0 so ace-- 1,3114C ce-0.75*AC 4:f r-,.? 0 5' U,75 07 '7 0 Z �O i�—A 7-6 0'7 1.3 V11 .7 ;oo 7 0 67 '.A ... : , . • I COMPUTATIONS . Stewart & Associates, Inc. 214 N. Howes St.....:'-ft. Collins, CO 80521 (303) 482.9331 By: Date Client: 6vnbe.14 Res( Sheet No. of ChkdBy: Date Project: PA(J/O 14011-geS pyD Subject 7Kegy1'ree 2e_Lenf fOh COMPUTATIONS Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 By: P) r?-- Date Client: '5-Unbe'/J- )?evLl Prl-Redief Sheet No. 5 of Chkd By: Date— Project:- Fvtrfo )40,mgs OLi- Pine wa0c, Subject �e 4-e nkllo v\ ponj 0f sJe 1 .33 711r �64i 2 Are a/:L/ 4501 i 1 31 9 117 7 .1. 0 7 7 1 I 1 -3 I q, 1 — 0-I I - I� i I(�!' i � ' I j � I �I I or'/ri-ion✓ �-;r�s�rrrc�.To� � : rt�,�� .Ij -- 1 � i �� j I 0. <I lk7 T- r, R3 Z- #"Z I D ).7 � 3 '�rl f�j T5- ii COMPUTATIONS Stewart & Associates, Inc. 214 N. Howes St..; Ft. Collins, CO 80521 (303) 482-9331 By: PJTZ Date z 3 Client: -5 e14 EeQI Prop'-e41 of Sheet No.of Chkd By: Date Project:- FerL o 1)01*4,0S ck+. PlAetA10o2 �y)7 Subject - -e 041 a h po nej S i I j T COMPUTATIONS Stewart & Associates, Inc. .,214N.Howes St. -Ft..Collins,C080521 (303)482-9331 By: Date 3 z Client: Sheet No. 7 of Chkd By: Date— Project:- PcIthO 801rAeS c,4- Phe-voa,4 PUL? Subject E -0 0 4, I. Re's +H' C 0 Ji re-21 &t fS AL inv�ler 01 e —3 AV (0 99 4) 92 r The dr- C1 0- ut) e4- Via 4 Fro i(9 '(5P vid co r r. IS �nl 1-� 4� grade11 e,, tice! ric I � I-e ;.-? .0 I li ! lip; l 71 07 St it o.. 0 i i! i! � i! I ! i i I j I i RIC ri �i I Gt 10 /Z) x /1-5 ki;.7o pung i 4- 15 C, 0 C4 pon(4 i6-5r Vki-. e cop 37 Pa 61� �/9=89Z;