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HomeMy WebLinkAbout08 - Design Report - West Winds Ph 4 - Sanitary Sewer 44�-Ib': � `2 Sanitary Sewer Investigation For West Winds Planned Community Phase 4 r Prepared By: HKM Engineering Inc. 920 Technology Blvd. Suite A Bozeman, MT 59718 E N G I N E E R I N G December 2007 Revised June 3, 2008 04S067.125 r1 sf t JUN 1 6 2008 4 ----------------- Sanitary Sewer Investigation For West Winds Planned Community Phase 4 Prepared For: Cascade Development, Inc. 1627 West Main St., Ste. 223 Bozeman, MT 59718 Prepared By: HKM Engineering Inc. 920 Technology Blvd., Ste. A Bozeman, MT 59718 June 3, 2008 04S067.125 00 ZACHI - ENS 6 - S ob Table of Contents Page Purpose..........................................................................................................1 Preliminary Conditions Summary................................................................................................... 1 Basisof Calculations....................................................................................................................... 1 ConveyanceFacilities..................................................................................................................... 1 Phase4............................................................................................................................................ 3 Conclusion...................................................................................................................................... 4 Figures Figure1 — Sanitary Sewer Plan....................................................................................................... 2 Appendices Appendix A—Peak Flow Capacity Calculations Appendix B—XL Annexation Agreement Page i H fN61NEE RING � West Winds—Phase 4—Sanitary Sewer Investigation June, 2008 Purpose This engineer's report is intended to address the Breeze Lane and Westwind Way sanitary sewer extensions for Phase 4 of the West Winds Planned Community. This report will determine the recommended sizing of the internal sanitary sewer system and the impact on the outlying sewer trunk lines. This report was prepared in accordance with the design criteria set forth in the City of Bozeman's Design Standards and Specifications Policy and the Montana Department of Environmental Quality Circular 2. Preliminary Conditions Summary The Far West Sewer Trunk Line is an existing 20" diameter sanitary sewer line that bisects the West Winds PUD south to north (see Figure 1), and will service the majority of the proposed West Winds Planned Community, with the exception of the northwest corner. Upon crossing the West Winds project and intersecting Baxter Lane, the Far West Sewer Trunk Main turns east on Baxter Lane, where it increases to a 24" main and continues to flow east down Baxter Lane. The XL Annexation Agreement(1997), which brought the West Winds property into the city limits, entitled the West Winds Community to a reserved sewer capacity in the original Far West Sewer Trunk line of 307,200 gpd. A copy of the XL Annexation Agreement can be found in the appendix of this report. This flow rate was based on a maximum total of 960 residential dwelling units and an average flow rate of 320 gallons per residential dwelling unit per day. The 320 gallon/residential dwelling unit/day figure is conservative. City design standards currently utilize 2.11 persons/dwelling unit and 89 gallons/day/person, or 188 gallons/day/dwelling unit and 150 gpd/acre for infiltration. West Winds is currently requesting sanitary sewer service for 960 units. To date in West Winds Phases 1, 2, and 3, 453 units have been platted. Y8 4.�I PA,,. NL At -.'1 -4-­ -W_ Basis of Calculations Ph a 14�� 45 3 133 '� The calculations and recommendations within this report are based on the regulations set forth in the City of Bozeman Design Standards and Specifications Policy and Montana Department of Environmental Quality Circular 2. Calculations are provided in Appendix A of this report. Conveyance Facilities An overview of the sanitary sewer layout for the Phase 4 of the West Winds Planned Community is shown in Figure 1. An eight inch diameter main will service Phase 4 of the subdivision, and connect to mains installed in Phase 3, which cross through park area and ultimately connect to the 20"� Far West Sewer Trunk Main at the intersection of Santa Anna Court and Tschache Lane, located in Phase 2. Page 1 of 3 AM INGINEI RING 4 West Winds—Phase 4—Sanitary Sewer Investigation June, 2008 Phase 4 The Breeze Lane sanitary sewer main extension will service approximately 8.5,acres in Phase 4 of the West Winds Subdivision. The Westwind Way sanitary sewer extension will service approximately 10.26 acres in Phase 4 of the West Winds Subdivision, and approximately 11.01 j acres in the future Phase 5 development. Upon full build-out of PhasS4, the Westwind Way and .� Breeze Lane sanitary sewer extensions will include approximately 6S living units in Phase 2 of oe the Farmington assisted living facility, approximately 6�nits in an Independent Living �N Retirement Community, and 5°single family home lots as detailed in Table 1 below. Assumed populations are based upon the preliminary site plan applications and the City of Bozeman t„ design standards for average persons per unit. There will be no flow from industrial plants, 3 ,µ_f \i major institutions or comm rcial facilities into this sanitary sewer system. Using the City of 4 ' Bozeman standard of 2.11 persons per dwelling unit, the city's design generation rate of 89 ✓ f`^�s sty gallons capita per day and using the Ten States Standard recommended peaking factor of 3.72)for flow into,,f#j Vest Tru ever, the estimated peak hourly flow for Phase 4 was " AL�,� G Sa�C calculated to be 0.12 efs, or 7.,gpd. This peak hourly flow rate is inclusive of an infiltration �u,a 61 dµs rate oel50 gallons/acre/day, see Appendix A for calculations. 7 y3 JMs The sewer flows from Phase 4 Breeze Lane extension and the Westwind Way extension will be ab✓� conveyed through 8" diameter PVC sewer mains located along the centerline of the proposed street alignments; the mains generally flow east connecting to mains within Phases 3 &4 (including Windward Ave and Hunters Way). Sewage will continue through the previous phase ,r �� 2A parkland, and ultimately connect to the 20"� Far West Sewer Trunk Main at the intersection of Santa Anna Court and Tschache Lane. Using Manning's Equation, and a minimum slope of '�0.4%, the full-flow capacity of an 8" main is 0.77 cfs, or 497,664°gpd. The peak hourly flow from Phase 3 and Phase 4 (including the Windward extension) will flow at approximatel 5.8 o of the 8"main capacity, well under the allowed 75% flow limit. 3q VO As previously mentioned, the sanitary sewer outfall connection for the Phase 4 Subdivision will be the 20"� Far West Sewer Trunk Main at the intersection of Santa Anna Court and Tschache Lane, located in Phase 2A of West Winds Subdivision. Flows from the Phase 4 subdivision will add approximately 78,502 gpd to the previous flow of 390,518 jpd from Phases 1 through 3 through the Far West Sewer Trunk Main for a total of 469,020°gpd. This additional flow from the West Winds subdivision will account for .260 of the Far West Sewer Trunk Main's maximum ftill flow. I 1 V. e D. 17,) —�-- S Table 1 : West Winds Phase 4 Sanitary Sewer Demands Page 3 of 3 ENGINEERING West Winds—Phase 4—Sanitary Sewer Investigation June, 2008 unit total count persons/unit gallons/person/day gal/day Phase 4 Villas ,, r Single Family 13 i ys( , 2.11 - 89 2,441.27 Du lexes 40 2.11 89 7,511.60 Farmington Phase 2 ('0/09 beL Memory Care 19�s I� ' �Z`1 89 1,691.00 Assisted Living units 27? 30 2.11 89 5,070.33 Assisted Living studios 3 f 1.1 89 293.70 Transitional Living studios 13= 19 1.1 89 1,272.70 Cottages 6 = 2.11 89 1,126.74 Single Family Lots 5 0L�_ 2.11 89 938.95 OK Ly3 za}�t�z,u a-IgF (ari3)� I = 2aB,L�po" Total 20,346.29 vs 2-2- 1 vy (�1 +a71-�+'�)2It+Iq + `3��3)l•I _ R58 �s��1 Conclusion It is the finding of this report that the existing City of Bozeman sanitary sewer system has adequate capacity to service the Phase 4 Subdivision. We also assure that the proposed sanitary sewer main extensions of Breeze Lane and Westwind Way will be designed and constructed in conformance with City of Bozeman and MDEQ standards. i/i Il Fp,_ /% Z. ASS4 SA 3 bolr a4 2? bdr 3 Page 4of3 PEAK FLOW AND CAPACITY CALCULATIONS West Winds Planned Community-Phase 4 Bozeman,MT The following calculations are used to determine the mean sanitary sewer flow and required pipe diameter for the Phase 4 Subdivision of the West Winds Planned Community. Using Manning's Equation,the full flow capacity of the proposed 8"diameter P�e"6-. o P� PVC Sewer line is: r82q \1r2 +r°1/2 rg k 2 _ (� Qrul=(1.486/n)*A*R2s*Sv2 Iwo where: QA,-t 4+p'I2 ZZq\\12 n= 0.013 for PVC Pipe �} (�- A=PlY= 0.35 ft2 10O0 P=2*PI*r= 2.09 ft R=A/P= 0.17 ft S= 0.004 d , 6sv a58�`� Qn 11= 0.77 ✓ cfs Calculate the peak hourly flow rate under developed conditions: Q„q 20,346.29 gpd (Table 1) V$ ,�219 /of A Qaw 0.031 cfs p q A QP.ak 75,688.20 gpd (3.72 peaking factor) v y Q Q-k= 0.117 cfs p,ISc-�5 Calculate the peak hourly flow,with an infiltration rate of 150 gallons/acre/day Area of Phase 4= 1876 (K Acres Qinfll = 2,814.00°N' gpd Qmax Qpaak+Qinril r7 Qmax= 78,502 gpd 15 `J¢,88 7 0.12 cfs n Its c,S 6 Q„ 2 Gh 3 9 Using the above parameters,velocity at the full flow in the 8"diameter pipe is: v=0.486/n)*132r3*S1r2= 2.20 d� ft/sec r22q +2,r1<I';� 4z Qma)Qrnu= 0.16 V-S fJiI$/oi%7 �'� � p,F fb+ 10*1;V 15.80% l a,s 70 QA� q f /22R } 2,IIx17 �Z Calculate peak flows and capacity of 20"Far West outfall. /r Ph 1 Qmax 181727 "-S 7 5,q � � ,��� ' Ph 2 Qmax 109:644 v S 13 1 ' 41 B T!`� PIS 3 3 �J1� Ph 3 Q_= 99,147 Vi y 4,7 jeJ / = ISM d �iM6Ar; `jr� �f1 Ph4Qmax= 78,502 4S !�?2,gIff1/,„i)172 + Z8r4fed (�hnGi I) 469,020 VS 4 �11 = 68,2A Wed = 4 66 q,s q P� Including Phases 1 through 4 0V 1 Qm.><= 469,020 gpd p 0.73 9 7S} l 33�2,II 8 q 1 cfs °L Q rna/ 3,11( Using Manning's Equation,the full flow capacity of the 20"Diameter Far West Trunk Main PVC Sewer line is: p, 3o c s Qfull=(1.486/n)*A*R2r3*Sv2 where: RM v,30 p,3q n= 0.013 for PVC Pipe � A=PlY 2.18 ft2 (yj�rl( r O 77 q Z P=2*PI*r= 5.24 ft 3 /' R=A/P= 0.42 ft rI� S= 0.004 L �s�jJ o r rl(� Qf"u= 8.78 Cf8 lt,_Y'1 X, YD QmadQfull= 0.08 ) 8.26% / [) / f U 0. , �B * H:\04\S067125\SEWER\SanSewSizing-WWPh4 5-29-08.►► x1s V XL ANNEXATION AGREEMENT bUZEM, CITY JUNTY PLANNING OFFICE r3ozeman CityCounty OS NOf?TH©OZEMAN AVENUE Planning Office P.O.©OX 640,PHONE,(406)5BO �MM� A5 71640q 406) 7 1 S - t MEMORANDUM TO: PIiII.L FORBES,D FROM: DEBBIB HECTOR OF PUBLIC SERVICE f DATE: DB�� ASSISTANT PLANNING DUMCTOIZ RE: XER 8- 1997 L LIMITED P ARTOERSHIP ANNEXATION-PA SEWER CAPACITY OF RESERYHD Pe'Section l4 of the XL Limited p Part ausldp check#1006 in the artncrshiP Annexation Agreemcnl, attached pi case 8, 1997 letter forwarding unt of$74,748.80, as well as a co Peas' find XL r�gnitiou of the a g the same, This paymcat de of Joseph W. Snbol's scrvcd p Ymcnt' the portion of the XI, pf°vtdcd for SID 621, and it, b3'g vity sow fs now cntltkd to r Limited Partnership Annexation tract' is Trunk lint a cscrvcd sewer capacity in the original Far West Sewer- the trunk is 307 200 Annexation Agrtep4 the total amount of acre a !Ions average daily flow(based on a reserved s '�capacity, maxim ota 60 residential dwelling units,and an average flow density of six units per residential dwelling unit per day.) rate P y.) of320 gallons per _r A copy of the fully executed Annexation A oa December 1, 1997'b R U �t,which was approved by the City convenience— Y esolutiou No.3216,and filed on December 4, 1997,is attached toryour foryour Please deposit thisroprL2jc �. You have questi6as regarding thispu to account,and subn3it a reca pt for deposit ton, Should a L Pleas'cat(me at 2364• It . l l DA/dla _ - cc JOSVIL.W.sabot,A:ttonicy at Law 1 • Xf.PARTNERSVIP ale aft iQ06 PA.130X fife- . StO r�rTunuc U4Itlltf/,UT 6 �Y,V .� � - •. :. r orr 1� M1� �lr� LOO 7 right-Of-way. Said easements will be riled with the Gallatin County Clerk and Recorder at the %1 time this Annexation Agreement is filed. a) 45-fee(for Baxter Line j b) 65-feet for Oak Street l c) 32:5-feet for North 27th Avenue d) 50-1feet for FowlcrAvenue 12- Slormivnler Mnslcr Plan. i 1.1 Landowner understands and agrees that a Stormwater Master Plan for the XL LIMITED PARTNERSHIP ANNEXATION for a system designed to remove'solids,04 gtrasc other Polhttanls frorh the runofrfrom the public strtxas must be provided to and approved by the city Engineer at the time of any future development. The master p _ must depict the►na)dmum si;, rctcntion/dctcntion basin location.and locale and provide msematts for adequate drainage, ways Within the area to t{ ransport runoff to the sormwatertingchanel(s .� Plan shall include side grading and elevation information, typical starmwater tletcnllon/retenlion basin and duchargc structure detat7s,basin sizing calculations,and atormwater maintemnCO plan. j' 13. Additlonal Term;of Wnivcrs. 710 Parties^ecogn1ze that these docu " Ls shall be tiled And of accord with the Qallatin County E:Ierlc And Recorder prior to the sak of any land wig h. xL uMIZxn PARTNERSHIP ANNEXATION: ( 77. Dies further Agree that the City may [Be these documents At any t1mc. 14. Rcservtd Scwcr Canaa r�, . . l.andowncr has proyicled the City$74,746.8Q as the pAyback required appurtenant to the real property heminabove described for Special Improvement District 621. in recognition of this remlot,drat portion of ti►e XL LIMITED P&M.,E SHIP ANNRXA7T()1�tract whiff is served by gravity sewers, shall he entitled to reservctl sewer capacity in tha original FAr.West Sower 1 Trunk lint:. The fetal amount atroscrvcxl sewer cA acit �the � .P Y trunk line shall be 307 200 gallons average daily flow(based on a residential density of six.units per AM, a maximum total of 960 residential dwellingsunits, and an Average flow rate of 320 gallons per residential dwelling unit per day) X' LIMITED PAJtThrRUffIP ANNEXATION AGREFyWr The undersigned Landowners a ffirnu that they have authority to enter into this Agreement 1 on behalf of their partnership.And to hind the partnership to this Agreement. IN WITNRSS WN)✓ItEOr, the parries hereto have caused this Agreement to he Iexecuted the day and year first above written. LANDOWNER it XL LMWM,D PARTNLrRSIIIP A Montana Limilcd Partnership By. �4�TAOMAS R LANE Its: �am--a1 part,y--r R Oi URT D.LANE STATE OFMONTANA ) :ss County of Gallatin ) _ On this 2SMday of ry, .„, _ _ a estate of Montana,personally appearrcl THOMAS 19 97 . before me,n Notary Public for the me to the Germsjem LrINE AND RODERT D. LANE,known la + limited partnership,and Acknowledgedof LIM n"M PARTNERSHIP, a Montana limited partncishi me that I hcy cxccutcd this instrument on behalf oCsaid p pursuant to the rower and authority vested in them. IN WITNESS WHEREOF.I hAva hereunto And AW=cd sat my hand my ofItclal seal As of the day and year first above written. (Seal) NotaryPrtbli britheStalcofMontnna Residing; Cam Commission RxpIres; 12n— CITY OPDOZEMAN By;Clark Johnson,CityManagcr ATTEST` a - Clcrlc of the 4cltym�MIL-M/�Ion-- XL r-lMMW PARTiML HIP ATSON AGRIig�,rp 1sXIII[I1T__, YA-WRIZ Ol RICIIT?'O pnomr T CRrAT10N OF RURA1.IMPRQy):MT'NT DIS7'RICT;S I FOR PAVEMENT CUR12 (:UTTER S1D ,WALK lIOULEVARD BIND DRAINAGFTO DAXTFR 1 X1,I,IMITVD PABIWERSUIP ANNEXATION The undersigned owner of the real property situated in the County of Gallatin Slab of Montana,and more particularly described as follows: 1 Northwest one-quarter of Section 2, Township 2 South, Range S East, Up.M., Gallatin County,Montana �. IN CONSIDERATION of receiving approval for annexation of the subject pro from the City or B PAY oyaman, along with accompanying rights and privi7cge3 and for other and valuable consideration, the receipt of which is hereby Acknowledged, and in rccognit,on of the impact to Ettxlcr Lane which 11 ba caused by the developmcnl of the aliovc-descrr'bcd property, has 1 waived and do hereby waive for itscl(T its.successors and assigns, the right to protest the creation of one or men; rural improvement districts for paving, curb, gutter, sidewalk, and drainage Improvements to Baxlcr Lane,or to make any written,protest against the size or area or cmatdon of the district be assessed in response to a duly passed{csoiution of intention to create one or more rural' - •improvement districts which would include the Above-described property. J This waiver shall be a covenant running with the Iand and shall not expire with the dissolution of the ii►nitedpartnership,provided however ads wadver4wfi apply to the hnds.henein described. , The terms, covenants aw Provisions or the Waiver shall oxtend to,aixi rtic�b n� mg upon [he successors-in-intcrest and assigns of the partdes hereto. • DATED this Ist day of____ngaeLmh j 1997. i XL UMITED PARTNERSHIP A Montana Limited Partnership . l THOMAS B.LA N13 Its: General partner 13Y•1 �c� C/ Y. ROIIBRTD.LAN13 Its:. DM-Al Parimar xr+ r+Tlrli'bn PIIR�HIP TIaW J11:RF.F?IEN'p Page 12 J i STATE OF MONTA14A) County of Gallatin ss I � - On this 2`5th d7 of . Montana,pthis 2 t appcan tl 7 H M ber0rc me, a Notary Public for the Stutc of AN the Partners ofXl,[,IMI p E and ROBERT D, LANE ncknowlad PARTNERSHIP, ana LANE. known to me Io be ' Sed !o me that they executed this Instrument on behalf of said limited cd partnership pursuant to the power nnq authority vested in them. - P above. IN WITNESS WIMBOF,I have hereunto set my hand alxl set my seal on the j date noted C KOry Public rStatc ofMontana (S u) Residing at Bozeau My Commission Expires; iZi /21/99 JJ t • i LTMT7Fp PAft MERSNI A1�1 P A MITON AWM&jV,?r Page 13 COMMISSION RESOLLIhoN NO. 3216 A RESOLUTION OF MONTANA, EXTENDING CITY COMMISSION OF THE CITY OF ROZEMAN, EXTENDINGT}{E BOUNDARIES OFSAIDCITYOFR02EMCM N, AS To INCLUDE WITHIPI THE CORPORATE LIMITS OF THE c i $OZEMAN TRACT OFLAND CONTIGUOUS TO SAID CITY, 70 l3E KNOWN AS . THE BAXTER LANE ANNEX ITY OF XL LIMITED PARTNERSy{p ANN (AND FORMERLY REFERRED TO AS THE I PARTICULARLY DESCRIpED, CATION REQUEST) AND HEREIN MORE WHEREAS, the City e of Bozeman received a request for ann Sabol on behalf of xation'from Joseph W. XL Ufnited Partnership, owner of the tract,requesting the City CommisMon to extend the boundarles.of the City of Bozeman so as to include a I land located West Oak Street extended and B certain contJ guou s tract of axterLane,Immediately west of Annie Subdivision, _in the County of Gallatin, State of Montana; and WHEREAS, an annexation staff report has -been prepared In accordance with the Cotnmisslon's goals and policies for annexation and was presented to the Co 16,.1997; and mmission on June WHEREAS, Commission Resolution No.3.184 was ado � pted by th e City Commission on June 16, 1997, declaring itto be the intent of the City,of Bozeman to extend the boundaries said City so as to include said contiguous tract within the of corporate 1units of the City; and WHEREAS, a public hearing on Commfsslon'Resolution No.31114 was duly noticed a�� nd opened'On July 21, 1997; and WHERF-AS`• the public bearing was continued to August 11, 1997,at which time It was conducted, and WHEREAS, no objections to said annexation were raised at the-public hearing; and . WHEREAS, the City did not receive any written protest from the real property owners of the area to be annexed; and WHEREAS, on August 11, 7 997,the Commission authorized and directed staff, upon satisfaction by the applicant of the conditions of approval,to prepare the necessary documents to proceed with the annexation of this tract In accordance with Commission Resolution No. 3164, and l WHEREAS. the provision of availab le services Including, bbt not limited to, rights-of- way, easements;water rights or cash In lieu, waivers of protest against creation of S1D's and 'water and sewer hookup fees, to said contiguous tract is the subject of a written agreement between the City and Thomas E, Lane and Robert D. Lane,partners In XL Limited Partnership, record owner of the tract;and WHEREAS, said contiguous tract is the subject of a 'In the office o Plat or Certificate of Surve i f the Gallatin County Clerk and Recorder's Office; and y, filed WHEREAS, the Bozeman City Commission hereby con y finds tiguous tract is in the be that the annexation of this Ij best interests of the City of Bozeman and the Inhabitants thereof and Of the inhabitants of the contiguous.tract. jr NOW, THEREFORE, BE IT RESOLVED by the CI I Montana: ty Commission of the City of Bozeman, iff SLqlon 1 That it is hereby declared that, pursuant to Title 7, Chapter 2, Part 43 following-descnbed p ro , M,C.A,, the property,�Y, which Is contiguous to the municipal boundaries of the City of Bozeman, be annexed to the City of Bozeman -and that the extended so boundaries of said City shall, be as to embrace and Include such 160:b acres of larvd, to wit: Northwest one-quarter of Section 2 Montana Principal Meridian, Gallado Coun Y, MOn 2 South, Ran e 5 tana. g. ' ty, Mon The Otte' OVYO date of thla annexation is December 31, 1997. j The annexation of the above-des cnbed tract is subject to the terms of the agreement dated_Decembar 1, 1997, by and between the City of Bozeman and Thomas.E Lane and Robert D. Lane,partners in XL Limited Partnership. PASSED AND ADOPTED by the Ci ty Commission of•the City of Bozeman,_Montana, at a regular session thereof held oa the 1st day of December 1997. A7tBT: DO E. S'iUECK, Mayor R0131N L SULLi N Clerk of the Commission APPROVED AS TO FORM; 4LJ. &yv < ��• pie a ��L�` a� �6 �' O �U o I ce r!� ��� rp �e q � ►= ww IR Ilil < .Ui Hill t` lYH��vnx� • cLil-sue U �... • 30�HYA �,, S in z arr�w c.W-1 law nssnn SIAM moswu i 11 Hoa I M.aa t]u.Ml„v u �8r � a 1 � a ' c►+u►wrntla �� I�� � � c i .I . . /l/ tx3ea�t M ti .O t+ttorty tiit'1+try ivWIIM n L34 AU300M 1 I - I r 1 • • 1 l 1 1 1 1 1 1 1 1 f 1 1 1 1 1 1 1