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HomeMy WebLinkAboutDrainage Reports - 07/09/1992Cod 'e- / Final opproved Report —AA w Date FINAL DRAINAGE & EROSION CONTROL REPORT FOR REDEEMER LUTHERAN CHURCH AT SOUTHEAST CORNER OF BRITTANY DRIVE AND TRILBY ROAD FORT COLLINS, COLORADO MARCH 2, 1992 (REVISED MAY 20, 1992) PREPARED FOR: REDEEMER LUTHERAN CHURCH PREPARED BY: PARSONS & ASSOCIATES CONSULTING ENGINEERS 432 LINK LANE PLAZA FORT COLLINS, COLORADO 80524 (303) 221-2400 PROJECT NUMBER: 92.01 LUT FINAL DRAINAGE & EROSION CONTROL REPORT FOR REDEEMER LUTHERAN CHURCH AT SOUTHEAST CORNER OF BRITTANY DRIVE AND TRILBY ROAD This final drainage and erosion control report has been completed in conjunction with site topography and construction plans for the development of a vacant five acre site in southeastern Fort Collins. This report was prepared utilizing the existing drainage information previously developed for this area and utilizing "The City of Fort Collins Storm Drainage Design Criteria and Construction Standards." PROJECT DESCRIPTION The Redeemer Lutheran Church is relocating their facilities to a five acre parcel located at the southeast corner of Brittany Drive and Trilby Road in southeast Fort Collins; legally designated as a parcel in the Northeast Quarter of Section 13, Township 6 North, Range 69 West of the Sixth Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado -1- (see figure 1). Initially a sanctuary and small offices are proposed for the site and, through a phased construction program, additional buildings including private school facilities will eventually be constructed. The proposed five acre site is currently in a P.U.D. zone and was split out of property owned by Dueck Colorado Properties to accommodate the Church's expansion needs. The site is bounded on the south and east by vacant and unplatted ground. Trilby Road forms the northern boundary and Brittany Drive forms the western boundary. Both of these streets are developed to their ultimate design with pavement, curb, gutter and sidewalks. Utilities and a drainage system are also in place adjacent to these roadways. The site slopes from southwest to northeast at grades from 5% to 7%. A native grass cover currently exists on the site; however, there is indication of erosion from adjacent sites and there is also erosion taking place in the bottoms of adjacent ditches. HISTORIC DRAINAGE CONDITIONS This site lies entirely within the Fossil Creek Drainage Basin. Flows typically ran from southwest to northeast and sheet -flowed overland to Fossil Creek (see figure 2). The initial construction of Lemay Avenue as Larimer County Road #13 resulted in some of these flows -2- PROJECT SITE VICINITY MAP N.T.S. P PARSONS AND ASSOCIATES FIGURE 1 VICINITY MAP being collected in borrow ditches before ultimately being discharged into Fossil Creek. A master drainage plan entitled "Fossil Creek Drainage Basin Master Drainageway Planning Study," August 1982 was completed by Simons, Li and Associates for the City of Fort Collins. Improvements identified as alternative 3 were ultimately selected and approved by the Storm Drainage Board. This alternative identified structural methods of improving Fossil Creek and identified a number of "on-line" detention areas which could substantially reduce or eliminate the need for detention on some sites. From 1984 to 1986, Brittany Drive, Trilby Road and South Lemay Avenue were constructed in.a series of construction projects. The first project, designed in April of 1984, was for the development of the Somerly at Provincetowne P.U.D. just to the west of the proposed church site. The drainage report and grading plan called for detention ponds and storm sewer to outlet on the church site where open channels would convey flows along the east side of Brittany Drive and the south side of Trilby Road under South Lemay Avenue to Fossil Creek. Although the site was never developed, the offsite improvements including Brittany Drive, the storm sewer under Brittany Drive, the waterline under Brittany Drive, and the offsite drainage channels were completed. These existing improvements are shown on the grading and drainage plan. In 1985 the Provincetowne/Portner S.I.D. was completed. The drainage report for this project identified all of the drainage requirements for the Dueck -3- Properties which drained towards South Lemay Avenue. The major streets within the Dueck Properties including storm sewer were constructed at this time. This included a small piece of Brittany Drive at the southwest corner of the proposed church site. Flows developed by this drainage report were the basis for the design of crossings for the South Lemay Avenue Project completed in 1986. In addition, since no overall detention was proposed the Provincetowne/Portner S.I.D. report identified the need for detention on a tract by tract basis for this property. As the report states "... this report assumes that on -site detention will be provided as tracts are developed throughout the Provincetowne/Portner project and the drainage facilities included in this S.I.D. have been sized accordingly." This includes all of the drainage basins within the Provincetowne/Portner Project including Subbasin D-4 where the church's five acre site is located. All Provincetowne/Portner S.I.D. flows and improvement sizing were based on historic 100 year flows. The "Final Drainage Report for South Lemay Special Improvement District #86" prepared by Engineering Professionals, Inc. in July of 1985 used the information developed in the Provincetowne/Portner S.I.D. report to size adjacent structures under South Lemay Avenue. Structures under South Lemay Avenue were sized to convey the historical 100 year runoff. Basically, drainage channels adjacent to the South Lemay Avenue Improvements intercepted runoff from the westerly properties and conveyed them to three low spots along South Lemay Avenue. Storm sewer was added when allowable street capacities were exceeded. No Text DeAI JAGE sc;4F-mAT1G P Berrreutir Y�.�oL.U�, Pu.o. 04' CGP BAhIiJ DZ T21L13Y eOA > F14.U2E 3 CAI CULATEO oITCU CAPACITY - 8o cfe S VIJ OEVELOPEO Qpp � 73,$ oevsL.oPGO 4,00 = 371.H 2- 42" CCP I CALCULATCO CAPACITY OF III PIPE-i - ZHO C4-i $ PROV INCETOWNE/PORTNER ESTATES SOUTH S.I.D. for Dueck Development Inc. Drainage, Map s of A E wuwrt .s a X lu�m�ymmlm�!m+�ll�mm I&1� Ed®Ifiil;`tlmug .612,121 l��[�on!'!go® I�®II�II.ILI_.IIY�II �:a�j}}jjL�9��..' om amommus©m u! IMECICIVAI©© maooamaoo unummm000 ummummumm mmummumum mmommm©!1�mm II�©mmumumm unnuummuni 000mmm000 LEA HORIZONTAL CONTROL O VERTICAL CONTROL ' ■ SPOT ELEVATION --42601 INDEX CONTOUR �- INTERMEDIATE CONTOUR © DEPRESSION -'—'— FENCE GUARD RAIL DIRT ROAD PAVED ROAD RAILROAD �'•••--- STREAM —� DITCH CULVERT HEADWALL C5 BUILDING Q TREE . OUTLINE L POWER-TELE. POLE Q STORM SEWER LINE ❑2 DESIGN POINT n Although the reports indicate that the existing improvements were designed to convey historic 100 year flows, the existing improvements are capable of handling additional water (see figure 3). The grass lined channel along the south side of Trilby Road would need to convey 61 cfs for the historic 100 year storm. The existing channel will convey 80 cfs. The culverts under South Lemay Avenue were originally proposed to convey the historic 100 year flow of 73.5 cfs including street runoff. Actually constructed were twin 42" RCP and single 36" RCP culverts which will handle almost 280 cfs. It is unknown why the actual pipe installation varies from the design flows indicated in the drainage report. Calculations for these improvements are attached. In summary, there are some existing improvements which impact the proposed church site. The Somerly at Provincetowne P.U.D. and adjacent property (known as Basin D-2 in the Provincetowne/Portner Drainage Report) located just west of the church site along Brittany Drive drain through the church site. Flows in Brittany Drive are intercepted by inlets along Brittany Drive and also run through the church site. The proposed detention ponds for this development were never constructed, but the outfall storm'sewer and channels necessary to carry the historic flows through the church site and under South Lemay Avenue are in place and will work even without the proposed detention. Otherwise, except for a small .66 acre area to the south of the proposed site (see figure 2), runoff from areas to the south, east and north run harmlessly away from this site -5- and will be contained in future developments. Flows in Trilby Road to the north are below this site and will be conveyed easterly by the existing Trilby Road curb and gutters. Channel improvements along Brittany Drive, Trilby Road and the culverts under South Lemay Avenue appear to be adequate and, in fact, have capacity to convey much more flow than the 100 year historic runoff. DESIGN CRITERIA The Rational Formula as identified in "The City of Fort Collins Storm Drainage Design Criteria' has been used to calculate runoff from this site. The Rational Formula is an excellent predictor of flows from drainage basins less than two hundred (200) acres.. Manning's Equation was used to identify the capacity of channels and gutters. All coefficients, nomographs and design values used in this report were as provided for in "The Fort Collins Storm Drainage Design Criteria." DEVELOPED DRAINAGE CONDITIONS We have provided for the design of drainage improvements for the Phase I Plan of this site. Additional development will need to provide additional detention as required. The proposed improvements are as follows: 0 EXISTING CHANNELS Existing graded channels exist along the east side of Brittany Drive and along the south side of Trilby Road. These channels were completed to drain Basin D-2 (18.30 Acres) as identified by the Provincetowne/Portner S.I.D. Final Drainage Report. Undeveloped 100 year flows were calculated to be 14.2 cfs from this Basin at the southwest corner of Brittany Drive and Trilby Road (Design Point 9). The existing storm sewer in this area intercepts street flows and provide inlet points from future detention ponds which will be constructed along the west side of Brittany Drive. The existing ditches have capacity to convey not only the undeveloped 100 year runoff (14.2 cfs) but also the developed 100 year runoff (61.2 cfs). The existing section along Trilby Road has an estimated capacity of 84 cfs. These ditches are unsightly, do not fit the proposed development and due to the slope and erodibility of soils in this area would be impossible to maintain. Based on the analysis and guidelines provided by the Provincetowne/Portner S.I.D. it is anticipated that these ditches will need to convey the undeveloped 100 year runoff of 14.2 cfs. Contributing areas to the south and west such as Somerly at Provincetowne will provide detention for their developments and releases only 100 year undeveloped flows. To convey these flows and eliminate erosion problems a -7- V 24" storm sewer has been designed to replace the open channel. This pipe will be constructed at a 3.0% grade which when flowing full will handle 40 cfs; considerably more than the undeveloped 100 year runoff of 14.2 cfs. A grassed overflow channel will be provided as additional protection should inlets plug. A easement has been provided for the proposed storm sewer. OFF -SITE FLOWS Runoff from the west and north of this site are identified in the Provincetowne/Portner Drainage Report and are conveyed by street improvements and adjacent channels easterly to South Lemay Avenue. Runoff to the south and east of this site sheet flow away from the site and except, for a .7 acre parcel immediately south of this site, have no impact on this site. ON -SITE RUNOFF Water will be routed through the site via the proposed parking lot storm sewer and drainage swales into a detention pond. This includes the entire site 0 area including a .7 acre area immediately south of this site. All of the runoff from these areas is routed to the detention pond. A temporary swale along the eastern edge of the site will insure that no drainage flows will impact lower property to the east. SEDIMENTATION/DETENTION POND A sedimentation/detention pond will collect flows from the entire proposed development site. These flows will be detained and a 100 year historic runoff will be released into the ditch along the south side of Trilby Road. The release of The 100 year historic runoff is provided for in the drainage analysis completed as part of the Provincetowne/Portner S.I.D. EROSION CONTROL WIND EROSION This site is located in an area designated as having moderate wind erosion potential. The existing natural grasses provide adequate ground cover 91 for the site in its natural state and the existing erosion from wind appears to be minimal. No erosion control measures are being proposed during the construction period for the following reasons: 1. The site is only 400 feet wide and has minimal exposure. 2. The construction will be completed during the summer when the potential for damaging winds is minimal. 3. The site will only be exposed for a period of two months before parking and landscaping improvements will be in place. This site will be 100% covered after construction is completed. Asphalt paving, irrigated landscaping and the proposed structures will provide permanent wind erosion control. WATER EROSION This site is located in an area designated as having high erosion potential from water runoff. Examples of this can be seen in existing drainage channels on the site. All runoff will be directed through drainage swales into a -10- sedimentation pond. This pond will be constructed first. and collect runoff and sediments during the construction process. This pond will be landscaped and continue to serve as a sedimentation facility to ensure continued water quality from the site. The pond will also function as a drainage structure which will insure controlled runoff from the site. -11- PARSON,�S& CLIENT fed een Pi LI,1 /, lad ChuTb JOB NO. P. of W • , ASSOCIA 1 LTCS PROJECT CALCULATIONS FOR gun b f� CONSULTING ENGINEERS Ft. Comm, Colorado BOS24 MADE BY J w DATE_ �" CHECKED BY DATE SHEET OF c C. I 1 I � 1146 I ` f_ ;-} d 36 •9� �_. I.15.�7 TI !(l ).. ,r ; 7/GO %90) I .VA + �T- _� _.-.I1-- • .. .I. _ \ _� -1_ T. . i ; : : ) : i. 1 I 1 f i , C PAcR�SONS & CLIENT kei{efw Lu� ew CIiwc4 JOB NO. JfV ol/ LUr ASSOCIATES PROJECT 1. / CALCULATIONS FOR KNAC7T / CONSULTING ENGINEERS . MADE BY Jw C DATE J Q 2 I Ft C*Mm, Colondo 8052I CHECKED BY DATc SHEET OF i hsto,,� Rug►F� ._ : --.. - - -�,�� _sl�,� i .,. _ _ , z _ 20. 3]h fj �Tc-,oa - .L•Y71�j:, (z) (I•(zs);)_500 ��- I --_�= 1Q1(,ss) (2z.3d1)�-'__I9,.�L=fli�l � � LiL &tej ' Q-t - l�)T('t 7�, 8f�%7) _'�_ iZ•- Il-- -- -�- - - . , ; !_ i } 7-- --, �-- � Fiom?�rl�_U�41t, alI g_5wQ'IPJ�dfi�Elenflt�...rIQ 00, 7S i �S �' i l.739 i --! i ' I TF �l:tS)��'�� r- -7 --1 -T- 1 --{ 1. 6 Cis ; 1 -- ---{ I _ C C C FM.y^� PARSONS? & CLIENT Wt mrf IuYelaf Ch(41A JOB NO. -f%72,01 LUl- ASSOCIA 1 LCS PROJECT CALCULATIONS FOR CONSULTING ENGINEERS Q> Ft Colli Colorado 80524 MADE BYE'✓ DATE _CHECKED BY DATE SHEET Of ofsl, Cos�- : _i--_f { ioo�—� our__' __ ��fs�) � _ � i_I � zzs_ ` zr cg, Ioo ._ z _cz ASIZ +— ._; of 13.0 110.1,971� Izs; (Z9 ! — ;— -'(8, 288 C06- iI, 97 :_ 4; oS0__� _ _ 9336_1rc T Fc.c I M4 de�c lop' s :rey.�lvtd �.x__r I , t I� -�r_r_ Irre�__S(L c 7 1 i C C PARSON,�STLC& CLIENFT RRed l CMff 14 l 1l04 CA U(G 61 JOB NO... L 6 1 U % ASSOCIA ! S PROJECT ' `� •' 1 �M CALCULATIONS FOR D� ' `411 i4 Vp lum 4 CONSULTING ENGINEERS FL CoMn*6 Colorado 8QS26 MADE BY �r DATE -CHECKED �`' 'rF CHECKED BY -DATE SHEET OF� +F I j v Mai ! ... L t-- -� - � �S70 (f,00� ; �' /0 %l � le VM ;ff? �e C - - C_� �1i alle �y I - C I T r- I _ , I -- -C I I! 1 - - i t II , t 7 , 1 f i I i t f I I FIGURES 189 MR-, FIGURE 2 0 0 100 0 0 -jo Ln Lo C) co to -1 tn L C\i FLOW FOR CIRCULAR PIPE FLOWING FULL BASED ON MANNING'S EQUATION n=0.010 psi rT�� rjNl it l,r4 nw ;n 2�17 '41 RAINFALL PERFORMANCE STANDARD EVALUATION RP e------------------S-T-A-N-D-A-R-D---FO-R--1 -APROJECT: ---- COMPLETED DEVELOPED SUBBASIN c4um self BY: ------------ IERODIBILITY I ZONE ----------- ------_--- ►;DI/SF-A:Ia69 if ff I Asb I (ac) S-o CoUC� DATE: ----------- Lsb I Ssb I Lb I Sb I PS I (ft) I (%) 1(feet) I � sso l �.o � � l gy. ► ii 70 ' �U Ceti .Iru ce-di Y-o elq- 3T'l he S Ftaml ladle 9 U f EFFECTIVENESS CALCULATIONS ----------------------------------------------------------------------I (PROJECT: Krdtem?f L&J-Aera4 Cti;Il4 STANDARD FORM B I I (COMPLETED BY: Jeff Couck I DATE: 3'Z-92 I I Erosion Control C-Factor P-Factor I I I Method Value Value Comment ----r---I--n------------------------- ESf4D�iSArd Gr45S 0.07 ------ /•0 =-----7---------- (%nc�rSl4l6Fd i}leCtS Gale Soi/ h o G o pAlk�;y d Qvdjf,(y 41r4J Gra,[I Filfns l• o o. P I Secirmr, f 7raP t,o 0. - ----------------------------------------------------! AREA I (Ac) I CALCULATIONS - -----I--------------- - ----------------------------! S. D (�q�r Soy ( GI, SZ 8 1• ! U�d,i�al�rA G•�ss 3� y Ac . I wrrgW 4C s. 0 37 f f Gravfl �i`I45 sill. flop ifs ' `► (31 X v)) X 100 7 s`� 1 ok " I I I I I -------------------------------=------------------------------------- lI/SF-B:1°2� CONSTRUCTION SEOUE•NCE PROJECT:. Redeewi LtIfArmi Chgti61UQ STANDARD FORM C. SEQUENCE. FOR 19 . "9Z ONLY COMPLETED BY: ,J��( (pu(�" DATE: 3 1-gZ 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 ri ----------------------------I------------------ OV.ERLOT GRADING ------------=-------------- I WIND EROSION CONTROL Soil Roughing I Perimeter Barrier I .Additional: Barriers Vegetative "Methods Soil Sealant I Other � I RAINFALL EROSION CONTROL � I I STRUCTURAL: Sfti'+of Cnnst(a(110'i Sedment-Trap/Ba'sin Inlet Filters�— Straw Barriers Silt Fence Barriers Sand Bags I Bare Soil Preparation I Contour Furrows Terracing Lf Asphalt/Concrete Pavi ng I Other ' � VEGETATIVE: Permanent Seed Plantinal I Sr�t L&Js(Qpr�y :Mulching%Sealant I I Temporary Seed Planting) Sod. Installation I I Nettings/Mats/Blankets I Other • l i = --------------------- ------------------------------- STRUCTURES: LNSTALLED BY MAINTAINED BY VEGETATION/MULCHING CONTRACTOR DATE SUBMITTED APPROVED BY CITY OF FORT COLLINS ON HDI/SF-C:1989 . IV No ZI lo 9, 37./ 7'(W) rA7/L By y y,p2F Z, 4 z w, 171-.41V 14OA;PIZ. 6 2040 0 V x 0 1A A 411 4 1,41z &-r 4/, 7-YIPFz /"VI/ (;:V) INVII67) - 03.51 STA. 62+21.69 4.29 So'-90'- RIIORARBEG M�M PRIME Mon I 1 3= oil oil nmorry IM—W M oil elm sohis- M—M PTA In MINIM MEN Z-7A FINAL DRAINAGE REPORT FOR PROVINCETOWNEIPORTNER S.I.D. CITY OF FORT COLLINS COUNTY OF LARIMER STATE OF COLORADO DECEMBER, 1984 Prepared by: Parsons « Associates Consulting Engineers 432 Link Lane Plaza Fort Collins, Colorado 80524 Project Number 84.Oe S.I.D. FINAL DRAINAGE REPORT FOR SOUTH LEMAY SPECIAL IMPROVEMENT DISTRICT a86 JULY 1985 PROJECT NO.: 407.1. Prepared for MSP Companies/Dueck.Companies 650 South Cherry St., Suite 1050 Denver, Colorado 80222 .(303) 399-98.04 Prepared.by: Engineering Professionals, Inc. 2625 Redwing Rd., Suite 110 Fort Collins, CO 80526 (303) 226-3852; 0 DRAINAGE STUDY PORTNER.ESTATES SOUTH DEVELOPMENT PHASE I TRILBY ROAD AND LEMAY AVENUE CITY OF FORT COLLINS December 5, 1983 Revised January 9, 1984 FKA PROJECT NO. 025-83 1 PREPARED FOR: MSP INVESTMENT CO. 650 South Cherry Street Suite 1050 Denver, CO 80222 (303) 399-9804 PREPARED BY: FAULKNER-KELLOGG & ASSOC., INC. 7190 West 14th Avenue Lakewood, CO 80215 (303) 232-8076 FINAL DRAINAGE REPORT FOR SOMERLY AT PROVINCETOWINE P.U.D. PHASE I Located in the N.E. 1.14, Section 13-6-e9 CITY OF FO=:T COLLINS COUNTY OF LAi ; I MER STATE OF COLORADO JULY, 1964 Prepared by Parsons €< Associates Consulting Engineers 432 Lir Lane Pla-a Fort Collins, Colorado 80524 !3(03) 221-2400 Project Number 84.12 BTR FINAL DRAINAGE REPORT FOR SOUTH LEMAY SPECIAL IMPROVEMENT DISTRICT #86 JULY 1985 PROJECT NO.: 407.1. Prepared for: MSP Companies/Dueck Companies 650 South Cherry St., Suite 1050 Denver, Colorado 80222 (303) 399-9804 Prepared by: Engineering Professionals, Inc. 2625 Redwing Rd., Suite 110 Fort Collins, CO 80526 (303) 226-3852;