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Home My WebLink AboutDrainage Reports - 10/14/1991G 7,/ Sy / ( -EUIt�uJ �( cGp y Final Approved Report Date__.___ FINAL STORM DRAINAGE REPORT FOR COUNTRY CLUB CORNERS P.U.D. (BURGER KING) October 14, 1991 STEWART & ASSOCIATES, INC. 214 North Howes Street Fort Collins, Colorado 80521 4% 1 STEWART&ASSOCIATES Consulting Engineers and Surveyors September 3, 1991 Mr. Glen Schlueter Storm Drainage Utility City of Fort Collins P. 0. Box 580 Fort Collins, Colorado 80522 Dear Glen: This is the final storm drainage report for Country Club Corners P.U.D. which is the site for a proposed Burger King restaurant. It is located in Block l of the Replat No. 1 of Evergreen. Park and is on North College Avenue approximately 600 feet south of Willox Lane. It is north of the.Union Colony Bank but does not include the Union Colony Bank as a part of the P.U.D. A new access drive will be built along the east side of the Union Colony Bank and the Burger King site. The site now has approximately one—half adequate vegetation ground cover and one—half gravel and asphalt parking and drives. The site slopes from west to east at approximately One Percent 0 %). The site is in the Dry Creek Drainage Basin but is not in the Dry Creek Flood Plain. The Major Storm Drainageway for Evergreen Park prepared by Engineering Professionals, Inc. and dated March 1981 indicates that proposed development in Block 1 should have onsite detention to avoid building some large drainage improvements downstream. We are proposing onsite detention. There is an existing 21—inch diameter storm drain running east from the Union Colony Bank. It presently does not have any inlets that allow storm water into the pipe. The 21—inch pipe was probably sized for onsite detention since its capacity at a slope of 0.36% is 8 c.f.s. We are proposing to construct a 15—inch storm drain north from the existing 21—inch pipe to the Burger King site. We will then discharge from the detention pond into the 15—inch pipe at the historic rate of 0.32 c.f.s. The release rate will be controlled by a restriction plate in the area inlet. The area of the Burger King lot is 0.74 acres, and the area used for the detention calculations was 1.17 acres which includes the north half of the new entrance road and the entire width of the private drive along the east side of the Burger King property. The College Avenue right—of—way was not used because it drains south in the existing east curb and gutter to Bristlecone Drive. The Union Colony Bank site does not have onsite storm water detention, and it was not included in the detention calculations for the.Burger King site. The South half of the entrance drive and the access drive lying east of the Union Colony Bank site drain south and will discharge into the proposed curb inlet and the 21—inch storm drain undetained. The James H. Stewart and Associates, Inc. 214 N. Howes Street P.O. Box 429 Ft. Collins, CO 80522 303/482-9331 54-11� ,/ Mr. Glen Schlueter September 3, 1991 Page 2 required onsite detention is 9,882 cubic feet as determined by the enclosed mass diagram. 'That part of the Neighborhood Service Center that lies east of the access drive will contain anchor and support shop uses. It will not drain westerly onto the Burger King site or the access drive. It is possible that this area may require some onsite detention at the time it is developed. The develop— ment of the Burger King site will not affect the drainage of the anchor site. A drainage easement is being dedicated on Lot 1 for the onsite detention pond. All of Tract "A" that contains the 15—inch storm sewer is being dedica— ted as a drainage easement. The existing 21—inch storm drain is located in an existing 20—foot easement dedicated on the Replat No. 1 of Evergreen Park. The Country Club Corners,P.U.0. is in a moderate rainfall erodibility zone and in a moderate wind erodibility zone. The site -is 225 feet east — west by 275 feet north —south plus the south part of the access drive which is 45 feet east —west by 282 feet north —south. The site is relatively small, and the building and parking lot will cover approximately 75% of the area. Most likely, the entire site will be stripped and graded in preparation for the building pad and parking lot and access drive. The main entrance drive will be constructed first in order to provide access to the Union Colony Bank before the existing asphalt entrance is demolished. The period between the stripping and the building construction is the most vulnerable to wind erosion. Once the bulding pad, curbs and utility lines are constructed, the unsheltered distance will be reduced to less than 200 feet as well provide a roughened surface and wind barriers. This activity should protect the site sufficiently from wind erosion so that no further action will be needed. Since the entire site will be exposed to rainfall erosion once it is stripped for grading operations, there is no practical way to -use vegetative measures to control the erosion. Therefore, we will trap the sediment before it leaves the site. Aggregate sediment traps will be placed around the area inlet and the curb inlet as soon as the 15—inch storm drain is constructed. The aggregate sediment traps will remain in place until the site is paved and there is no further potential for rainfall erosion. The Rainfall Performance Standard Evaluation for the site and Effectiveness Calculations of the.erosion control preventive measures are included. A Construction Sequence is also enclosed. The historic and developed runoff calculations and the mass diagram for the detention pond are included as a part of this report. If you have any questions regarding this final report, please call. Sincerely, Richard A. Rutherford, P.E. & L.S. President jrr enclosures RUTy�•.. 5028 5•. Be SU13JEGI �ST LJ1LF"=� �_\\/.�� L.—<_�CJ�1'.L� U,• BY ice l{/ -- —• UAIE��C'• PP CC',/ti_IIAl6�'�L—J��N�� Li=Sl'GF.7_ SHEET NO.--------.— -----------=-------- PROJECTNO.---------- R,1= A ) P—A l tl/AJro ro DC-76,Urro U POAJ� o„ .L of / GP—oEs A P-EA z 2G X Z25 = /./7 ,q c. Zo'v,v(, ZMpe.evlous Ar�E4 = 0.874�, 7¢•¢% PErZ'vlous Ar-aA = '6.3o.4,. _ '34 0, G 7 H,aT C Zyn o,2 x /,.3s x i, 17 = O, 3 2- c.c.s•.. HrJT. `� loyR _ O.Z X Z,4 X /•17 = C7• SG GF•S• TG;32AAJU. µ11T. pIooyFP = /•ZSX 0.2:X (-,OK /./7__ 1,17c-, S. DES. Q= D•79 x Z, 3 X 3 c..F.S, D e v. Q Ip y/e•. 0.77 x . 4/ 1 X l• I7 = 3 .7I To= 4M,v100�,� : l:Z.sx 0.79 x 7.2 x k/7 = b•3Z c.FS SU13JECI b_.iiL--! /_r_t---- —['i'_— '.L 1 _'_`:; UY---%�=� —. DATE till il'.:1/——XL ALL SHEET NO.--�---- -FO PROJECT NO.---------- T/M G (M,Cie CA = cl S. V OLVME IFT"j I.ZSx 0,71 x l.n = I •.I SOI 0 z0 S Z ro . 03 1 2.3 L '3o 4-.Is 9- $► grss8 4D 3.5: 9744- SO 3.0 ': ;_ 3.48 / o, 4 4.0 0Z 10, 87Z %0 L. BS Z /5- 11� fir,. zo I. q..3 /• r,� I1, qsZ 12, oo0 lv, 00 0 I> G 000 Z.0& T/ AA & (n, �N) 4y - SUBJECT BY —= _LL2LAL DATE J / `s` f. Jy� (,l_�,%------.-------------- SHEET NO.— PROJECT----- R e s IF P_ IC,7io N PC, /A r6 :B A DoPTH = 75.1-g 3. l3; VOLUNt E e) 176TEIUT10 VOA V nA 6 O F S�.D iM ENT T12 41P± i t TOTAL S ►TE AP -EA = /• 59 :A: j _ %RECjvreED V0(.UME OF:.s.I;b'Ili�/yt.�vT T�-9P = /00 yD� X /.59 4z93 Fsi i 1 t/ ' RAINFALL PERFORMANCE STANDARD EVALUATION '-------------------------------------------------------------------- PROJECT: Cou v.-r,ey CLVe, Co,e..vEes ? U. 15. STANDARD FORM A B V126Ee_. ki ucG SIT E +COMPLETED BY: IL' A e- DATE: 9 3 I--------------------------------------------------------------------- IDEVELOPEDIERODIBILITYI Asb I Lsb I Ssb I Lb I Sb I PS ISUBBASIN I ZONE I(ac)I (ft) I (a) I(feet) I (%) I (%) --------------------- I _ -I ------- I -------I ------- I ------- I BArl,4j A, /�10DeleA7E! /•07 Z7a--1 0.57. 4^/ I 1 Boslo F, I Mooeegrcl o:51 I 35o t��•,7%`i 30S j 6,s7 j 14L_L_ i co�-•1 �e ��h l 5� - J 1/ GL'r2.c..s WL-ct.F. •1- w; � �e -7 3 % 1 - ---------------. HDI/SF-A:1989 ---_ - JA,YOARY 1991 8-18 bESIGN CANER:_ EFFECTIVENESS CALCULATIONS --------------------------------------------------------------- PROJECT: C o v"Tlzy C G vp C Oe"CEJ P. u• D, STANDARD FORM B f3 vR, &eye. & iN` (�r6 COMPLETED BY: E , A, Q DATE: MAJOR BASIN Erosion Control 'C-Factor P-Factor Method Value Value ---------------------------------------- BAR.,=..f01L- /-00 /•00 SEDIME.UT 79A P /. 0 U (-).SO BL,I(-D/A)6. 00 0/ /, 00 BASE C_oup-JE _ 6110. /• 60 PS a 73 SUB BASIN AREA (Ac) Comment ------------ -------------------------------------- CALCULATIONS B UILi D/NG AzaA. O..0 B ars Goupj& /• /Z Ac, B AP-rz (ok0vN•p 0, 4--1 A,, LAJTD �C. c CO�OG X 0101) +( /Z x 0.10) 4-(0.41x1,w) � /• Sq o- 3 3- fir° "P„ =pSU 0.33 x O's-0 x 100 = 63 %, ----- ------- ------ ------- --------------------------------------------- I DI/SF-B:1989 • I CONSTRUCTION SEQUENCE PROJECT: C 0L) U-rf-V C Lu F3 CoQ.A)r7es h, U.7D, (Hur 7-9) STANDARD FORM C SEQUENCE. FOR 19 e-1L ONLY COMPLETED BY: e.; . /Z, DATE: 9/3 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 G �J --------------------- OVERLOT.GRADING WIND EROSION CONTROL Soil Roughing Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other 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 C om-c-rp-VCT CURB �gJEMENT VEGETATIVE: Permanent Seed Planting' Mulching/Sealant Temporary Seed Planting! Sod Installation Nettings/Mats/Blankets Other STRUCTURES: INSTALLED BY -IAnI A IMI IJ IAIS MAINTAINED BY VEGETATION/MULCHING CONTRACTOR DATE SUBMITTED APPROVED BY CITY OF FORT COLLINS ON HDI/SF-.C:1989 JANUARY 1991 8-20 DESIGN CRITERIA SUBJECT C �jv nJ Lt —C�t�V iS.:S?r' •`_ �>_�'—/—C 1. BY DATE _QjLT. W'7q/ —�A,5/lU ��—gUa1—Q�f_ CAl-�cv�BZL1111. SHEET NO.--g----- ---------------------- PROJECT NO. ---------- A P.eA = /• z3 A r M PEp.V10u-t AP_ eA 10/ Ac, $i.l Re 1? vt0�r � P A. O,zz. Ac... /7. 9 i DrsV. TG = :1.87(i.I p.SJevo'z- 9 M) u; • 0. 7 Z /3 - v£v. Q zy� = p.BG x Z•40 x l•13 2,75 C..F.X., DEv. Q toy,¢ - 0`8.& x rc = 4 MIN.. D Ev: Q lopyte - /• ZSx 0.'8e x .7, Z X l•z 3 �}tCVeB J7 er C A P A iT-y (Fr'ou NomoaeAVN Fla.. yo =O•(c GAPAc.i-ry c 125' e,FJ' FT _ bZSXCJ = SG•F.f. 4 91 ok. C APAC,ITy of Zl� h-•G+� S = 0.36% $.5 G•Ff. o% Qioyw, = 4-•BI G.FS, +0.3LC.ra. = s.13C.G, STEWART&ASSOCIATES Consulting Engineers and Surveyors September 23, 1991 Mr. Glen Schlueter Storm Drainage Utility City of Fort Collins P.O. Box 580 Fort Collins, Colorado 80522 Dear Glen: This is regarding the overall drainage plan for Country Club Corners P.U.D. The shopping center was approved as a. final plan. March 27,-1974. The drainage plan is shown on Sheet 21 "B" of 21 of the utility plans prepared by V.T.N. Colorado Inc. It was called Evergreen Park Shopping Center at that time. The Union Colony Bank building was built at that time and water lines, sewer lines and storm sewer lines were also built. In 1985 a preliminary plan was submitted for the site and was named North College Plaza P.U.D. Its layout was changed from the 1974 plan. The revisions of the layout required the 21—inch storm sewer to be abandoned; however, it was not. Since the 1985 plan was never finalized and there is now a new owner of the center, I think the•.1985 plan is null and void. Our final drainage plan for the Burger King site uses the existing 21— inch storm sewer to drain the pads along North College Avenue. The Burger King site has onsite storm water detention planned because the downstream drain lines are not large enough to carry the undetained 100—year frequency storm runoff. It is unknown at this time exactly -how the overall site will be developed; therefore, the 1974 drainage plan, which is the only plan with final approval, should be used. At such time as there is any revised development proposed on the overall site,.a new.drainage plan must be submitted incorporating a new design for that specific site plan . This plan does not adversely affect any future site plan on the total shopping center site. In fact, it is the safest plan for any future revisions that may happen. I trust this will answer your questions regarding the overall site drainage. If you have further. questions regarding this matter, please call Sincerely, Richard A. .Rutherford, P.E. & L.S. President jrr James H. Stewart and Associates, Inc. 214 N. Howes Street P.O. Box 429 Ft. Collins, CO 80522 303/482-9331 0 0