Loading...
HomeMy WebLinkAboutMeridian Town Center - Village Center Development - Storm Water Management - Engineering Drainage Report (4)Meridian Town Center Village Center Development Meridian, Idaho STORM WATER MANAGEMENT— ENGINEERING DRAINAGE REPORT OWNER CenterCal Meridian, LLC 7455 SW Bridgeport Rd, Ste. 205 Tigard, OR 97224 Ph: 503.968.8940 ENGINEER ice* 10961 The Land Group, Inc. Jason Densmer, PE qT�c �pP 462 East Shore Drive J OF NDI Eagle, Idaho 83616 Ph: 208.939.4041 Fax: 208.939.4445 9-24-12 Project No. 111049 or Site Planning • tnndscape. Architecture .Civil Engineering *Golf Course Irrigation & Engineering -Graphic Communication -Surveying 462 E, Shore Drive, Ste. 100, Eagle, Idaho 83616 • P 208939.4041 F 208.939.4445 • www.thelandgroupinc.coni May 22, 2012 SITE DESCRIPTION The Meridian Town Center project is located at the northeast corner of the Fairview and Eagle road intersection in Meridian, Idaho. The entire project consists of approximately 90 -acres. The Village Center phase of the development encompasses approximately 65 -acres. The property is currently undeveloped and bordered on the east by Kleiner Park (City of Meridian), to the north by the Power Center Phase of Meridian Town Center, to the south by Fairview Avenue and to the west by Eagle Road. The project will result in the construction of a lifestyle shopping center with a broad selection of apparel, home goods, entertainment and restaurant opportunities. This report analyzes and provides recommended drainage facilities to serve the needs of the project. Construction documents of the improvements have been prepared and show final details necessary for construction. SITE ASSESSMENT OF SOILS & SEASONAL GROUNDWATER GeoDesign, Inc. has prepared a geotechnical engineering report for the property, dated September 6, 2007 (copy attached as Appendix C). According to the study, groundwater was encountered at a depth of between 18.5 and 20 -ft below the ground surface. Generally, the soil profile consists of a thin mantle of silt overlying sand and gravel alluvium. Drainage systems are designed to penetrate the overlying silt and introduce storm water discharge to the sand and gravel alluvium. The geotechnical testing of the percolation rates in this strata indicate expected infiltration rates between 16 and 63 -inches per hour. The drainage systems include a filter sand medium, which will limit percolation to 8 -inches per hour. For design, we have used an 8 -in per hour expected percolation rate for facility sizing. PEAK RUN-OFF RATE & SYSTEM SIZING 100 -YEAR EVENT AREAS (SEE DRAINAGE AREA EXHIBIT) The proposed storm drainage will sheet flow across asphalt and landscape areas to storm drain inlets. Storm water will pass through sand and grease traps priorto discharging to seepage bed facilities to allow the storm water to percolate into the existing sub soils. Provisions have been made to collect roof drains and pipe them into the seepage beds. The drainage systems have been designed to store the 100 -year, 1 -hour event (1.0 in/hr, time of concentration = 60 min.). The drainage calculations are shown in Appendix B. Ir Site Planning -Landscape Architecture .Civil Engineering *Goff Course Irrigation & Engineering o Erophic Communication -Surveying 462 E. Shore Drive, Ste. 100, Eagle, Idaho 83616 • P 208.939.4041 F 208.939.4445 o www,thelandgroupinc.com May 22, 2012 Appendix A Site Drainage Areas ,r Site Planning ILandscape Architecture •Civil Engineering •Golf Coarse Irrigation& Engineering -Graphic Communication -Surveying 462 E. Shore Drive, Ste. 100, Eagle, Idaho 83616. P 208.939.4041 F 208.939.4445 • www.thelandgroupinc.com May 22, 2012 Appendix B Drainage Calculations Ar Site Planning o Landscape Architecture -Civil Engineering *Golf Course Irrigation & Engineering +Graphic Communication •Surveying 462 E. Shore Drive, Ste. 100, Eagle, Idaho 83616 • P 208.939.4041 F 208.939.4445 e www.thelatidgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 1 (Bldg AG -100) Total A = 9,450 s.f. Pervious =s.f. C= 0.10 Impervious*_= C= 1.00 Weighted C = - n"' Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 1100 = 3.10 in/hr, Q100 5/22/2012 V25 = ::ass J. V100 = S' "'C'- c.E Thompsons Rule (1" per hour) I = 1.0 in/hr (100 -yr Return Period, Duration= 60 min.) Q = 0.22 cfs (Q at 60 min.) V =- 788 CJ, System Size L=21ft W=9ft D=9.0ft Vr volume of drain rock provided Vv = 680 r.=. void volume provided Vk =` 126 c.f. percolation volume provided e.f, total storage volume provided by seepage bed ����I�I���} �y�806 '•IiYi�ii�iliiii OKAY OK,1Y Time to Empty - k= 8.0 in/hr percolation rate t;�-.t time to drain required storage volume S&G Trap Check Vault Size = jOldcastle New 1000 gal. Number of units = 1 Baffle Area/unit = 7.08 s.f. Drainage Area 1A = 9,450 s.f. Max Flow =; OK,1Y Site Planning Landscape Architecture - Civil Engineering : Golf Course Irrigation & Engineering. • Graphic. Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 � P 208.939.4041. • F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) 5/22/2012 Storm Drainage Calculations Drainage Area Characteristics: Area 2 Total A= 80,981 s.f. Pervious= s.f. C= 0.10 Impervious = 80,981 s,f. C= 0.85 Weighted C =',.85 Tc= 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 = 15cls 1100 = 3.10 in/hr Q100 = '�i:1v ens V 2 5 4 :. . V100 =7 -J, Thompsons Rule (1" per hour) I= 1.0 in/hr (100 -yr Return Period, Duration = 60 min.) Q 1.68 r - (Q at 60 min.) V - m,77-" w,$. System Size L-90 ft W=15 ft D=9.0ft V r%,7$.a ;..r', volume of drain rock provided Vv = 4,860 c.f, void volume provided Vk = 900 c.f. percolation volume provided 5,760 c.f, total storage volume provided by seepage bed lavAMIA 0KAY Time to Empty _ k = 8.0 in/hr percolation rate r s time to drain required storage volume 5&G Trap Check Vault Size - Oldcastle New 1000 gal. Number of units - 2 Baffle Area/unit 7.08s.f. Drainage Area 1A - 80;981 s.f. Max Flow = =5 = OKAY - Site Planning .. Landscape Architecture• Civil Engineering . Golf Course Irrigation & Engineering - Graphic Design - Surveying 462 E. Shore Drive, Suite 100 ..Eagle, Idaho 83616 • P 208.939.4041 - F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 3 Total A= 179,312 s.f. Pervious= s.f. C= 0.10 Impervious= C= 0.85 Weighted C Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q 2 5 1100 = 3.10 in/hr ' Q100 V25r-.6 c, V100 ^,68 r.>. I = 1.0 in/hr Q V Rule (1" 5/22/2012 (100 -yr Return Period, Duration = 60 min.) (Q at 60 min.) System Size L = 200 ft W = 15: ft _ D = 9.0 ft Vr= 27,0310t;.?, volume of drain rock provided Vv 1,800 eJ, void volume provided Vk = 120M cv.f percolation volume provided z1,c.00q c.f. total storage volume provided by seepage bed Vtotai> Vioo?-• Time to Empty 8.0 in/hr percolation rate 4.f, h� tune to drain required storage volume S&G Trap Check Vault -Size = 10ldcastle New 1000 gal. Number of units =F4 Baffle Area/unit- rea/unit-Drainage _ DrainageArea 1A = 179,312 s.f. W Max Flow z -� , > mow : OKAY .,:�; Site Planning - Landscape Architecture - Civil Engineering -Golf. Course Irrigation & Engineerings- Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 • P 208.939.4041 • F208.939.4445-www.thelandgroupinc.com Village Center (PN 111049) 5/22/2012 Storm Drainage Calculations Drainage Area Characteristics: Area 4 Total A= 83,445 s.f. Pervious= s C C= 0.10 Impervious = 83,445 s,f. C= 0.85 Weighted C = _I "."_ Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 In/hr Q25 = 3.66 cls 1100 = 3.10 in/hr Q100 = x1'05 V25,3213 V100 = 4,043 Thompsons Rule (1" per hour) I = 1.0 in/hr (100 -yr Return Period, Duration = 60 min.) Q = 11631' (Q at 60 min.) V = 6,:';11 C' f. System Size L=93ft- W=15 ft D=9.Oft Vr = , s volume of drain rock provided Vv = 'z,U22 c. f, void volume provided Vk= 930 c.f, percolation volume provided 5,952 c.f. total storage volume provided by seepage bed 1 Vtotal>-V100? • Time to k = 8.0 in/hr percolation rate a 1,3 hV, time to drain required storage volume S&G Trap Check Vault Size joldcastle New 1000 gal. Number of units= 12 Baffle Area/unit - 17.08 s.f. Drainage Area 1A = _ 83;445 s.f. Max Flow = S,05- efs NEMIMM 0.36 fps DKNY Site Planning - Landscape Architecture, Civil Engineering . Golf Course Irrigation & Engineering - Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 • P 208.939.4041.- F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) 5/22/2012 Storm Drainage Calculations Drainage Area Characteristics: Area 5 Total A= 148,997 s.0 Pervious= s.f. C= 0.10 Impervious r,,:1 s C= 0.85 Weighted C=J�:v' Tc= 10 min. Rational Method/Triangular Hydrograph 125- 2.25`in/hr - Q25 = 4.$4f: 1100 = 3.10 in/hr Q100 = 9,011 cz" V25 = 5, "O c,-". V100 = 7,219 c.f. Thompsons Rule (1" per hour) 1 = 1.0 Whir (100 -yr Return Period, Duration = 60 min.) Q = '1.51 cats (Q at 60 min.) V - 113,354 c,f, System Size L= 191 ft W=13ft D= 9.0 ft Vr - 22;34-, c.. volume of drain rock provided Vv 3,539 e,L void volume provided Vk L6TS percolation volume provided + -,10,594 c.f, total storage volume provided by seepage bed Vtotal>_'V1002 • Time to Empty k = 8.0 in/hr percolation rate l 4 :_r= time to drain required storage volume S&G Trap Check Vault Size= jOldcastle New 1000 gal. Number of units = 3 - Baffle Area/unit 7.08 s.f. - Drainage Area 1A - 1148,997 s.f. Max Flow !0) "; . + ilk p it OKAY Site Planning - Landscape Architecture • Civil Engineering - Golf Course Irrigation & Engineering- Graphic. Design - Surveying 462 E. Shore Drive, Suite 100 • Eagle, Idaho 83616 , P 208.939.4041.• F 208.939.4445 � www,thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 6 Total A = 267,835 s.f. Pervious= s.f. C= 0.10 Impervious = C= 0.85 Weighted C Tc= 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25= 1100 = 3.10; in/hr Q100 = =.6.20 efs 5/22/2012 V25 ' £..f. - V100 =. 12,97e Ca . Thompsons Rule (1" per hour) = 1.0 in/hr (200 -yr Return Period, Duration = 60 min.) Q 5,23'c a (Q at 60 min.) V ° 3.972 r.,:. L = 343 ft Vv = ''6,052 C'C Vk = 2,921 c.f. OKAY System Size W-13 ft- D=9.0ft volume of drain rock provided void volume provided percolation volume provided total storage volume provided by seepage bed Time to Empty k = 8.0 in/hr percolation rate - =- _ a:> time to drain required storage volume S&G Trap Check Vault Size= Oldcastle New 1000 gal. Number of units - 15 Baffle Area/unit = 17.08 s.f. Drainage Area 1A= 1267,835 s.f. - Max Flow _#ctws: '!ii k Im�:.-6'r f ,'-' OKAY Site Planning - Landscape Architecture - Civil Engineering - Golf. Course Irrigation & Engineering- Graphic Design - Surveying 462 E. Shore Drive, Suite 100 • Eagle, Idaho 83616 • P 208.939.4041. • F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) 5/22/2012 Storm Drainage Calculations Drainage Area Characteristics: Area 7 Tota l A = 64,511 s.f. Pervious = s.f. C= 0.10 Impervious =C'4,53"s.f. C= 0.85 Weighted C Tc = 10 min. Rational Method/Triangular Hydrograph 125 - 2.25_in/hr Q25 = R.&4 �Os 1100 = 3.10in/hr Q100 = 3 -SO is V25 = ','_cH .:i. V100 = Thompsons Rule (1" per hour) = 1,0 in/hr (100 -yr Return Period, Duration = 60 min.) Q= 3,26 fs (Qat60minj V = 4757C c,,1E System Size L=135 ft W=8ft D=9.0ft V - 9,120. volume of drain rock provided Vv _ 3,888 c,f, void volume provided Vk - 720 c,f, percolation volume provided • 4,608 c.f. total storage volume provided by seepage bed Vtotal? V100? Time to Empty k = 8.0 in/hr percolation rate `''; i. '3'dies time to drain required storage volume S&G Trap Check Vault Size - Oldcastle New 1000 gal. Number of units - 2 Baffle Area/unit 7.08's.f. d� Drainage Area 1A- 64,511s.f. Max Flow = 330 efs + U fps OKAY '. Site Planning - Landscape Architecture - Civil Engineering , Golf Course Irrigation & Engineering - Graphic Design - Surveying 462 E. Shore Drive, Suite 100 • Eagle, Idaho 83616 - P 208.939.4041 • F 208.939.4445 • www.thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 8 Total A 44,450 s.f. Pervious- sJ. C= 0.10 Impervious= 44,450 M. C= 0.85 Weighted C = D -S-5 , Tc= 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 = 2,95 cas 1100 = 3.10 in/hr Q100 = 2,69 dhi V25 = 1,56> V100 = 2,154 C a. 5/22/2012 Thompsons Rule (1" per hour) I= 1.0 in/hr (100 -yr Return Period, Duration = 50 min.) Q = 0,87 65 (Q at 60 min.) V 31.11'19 r:.%. L=,74 ft Vr = 6,6ho C.f. Vv = �,F64 c -f. Vk 493 c,f. r 3,t570f OKAY System Size W= 10ft D=9.Oft' volume of drain rock provided void volume provided percolation volume provided total storage volume provided by seepage bed Time to Empty k= 8.0 in/hr percolation rate yrs time to drain required storage volume S&G Trap Check Vault Size = 10ldcastle New 1000 gal. Number of units= 2 Baffle Area/unit - 7.08 s.f. Drainage Area 1A- 144,450s.f. Max Flow ery€ rfs ml�- ® &, _q fps 01<1AY Site Planning - Landscape Architecture- Civil Engineering - Golf Course Irrigation & Engineering .• Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 - P 208.939.4041 • F 208.939.4445 • www.thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 9 Total A= 299,250 s.f. Pervious= s.f. C= 0.10 Impervious = aC= 0.85 Weighted C Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 = .3.14 ck 1100 =3.10 in/hr Q100 = '3u.'z cfs V25 = 3,524v:J, 5/22/2012 Thompsons Rule (1" per hour) I = 1.0Sin/hr (100 -yr Return Period, Duration = 60 min.) Q = �81 C (Q at 60 min.) V = 21,191 ,.f. L= 178ft Vr= 44,4356c.f Vv 17,942 c.f Vk 3,323 c.f. 2_ .265 c.f OKAY System Size W=28ft D=9.0ft volume of drain rock provided void volume provided percolation volume provided total storage volume provided by seepage bed Time to Empty k = 8A in/hr percolation rate 4A °Wtime to drain required storage volume S&G Trap Check Vault Size= jOldcastle New 1000 gal. , (2-1500 gal.) Number of units= 5' Baffle Area/unit =I 7.08 s.f. Drainage Area 1A = 1299,250 s.f. Max Plow Site Planning -Landscape Architecture - Civil Engineering � Golf Course Irrigation & Engineering • Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 • P 208.939.4041.- E 208.939.4445 - www.thelandgroupine.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 30 Total A = 326,703 s.f. Pervious = s.f. C= 0.10 Impervious= S,"e' C= 0.85 Weighted C Tc= 10 min. Rational Method/Triangular Hydrograph 5/22/2012 125 = 2.25 in/hr Q25 = 1100= 3.10 in/hr Q100 7 1 V25 = 10,99 7.08 s.f. V100 = t-S'a"'O 0. 1326,703 s,f. - Max Flow = Thompsons Rule (1" per hour) I = 1.0 in/hr - (100 -yr Return Period, Duration = 60 min.) - Q u, 3 c's (Qat 60 min.) V = 23,14. 0, System Size L = 320 ft W = 17 ft - D = 9.0 ft F Vr 4%960 c.;, volume of drain rock provided Vv 19,584c,C void volume provided Vk =` 3,627 c,f, percolation volume provided 23„211 0. total storage volume provided by seepage bed �_ 17t0�i� �� • ' Time to Empty k = 8.0 in/hr percolation rate s a=r� time to drain required storage volume S&G Trap Check Vault Size = jOldcastle New 1000 gal. Number of units -F6 Baffle Area/unit 7.08 s.f. Drainage Area 1A = 1326,703 s,f. - Max Flow = ,. '9,76 .cts jjjjjjjn• ..: • 0.4”? fn" Oh d.Y Site Planning - Landscape Architecture• Civil Engineering - Golf Course Irrigation & Engineerings- Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 • P 208.939.4041 - F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics: Area 11 (Bldg AD -100) Total A = 7,991 s.f. Pervious= s.f. C= 0.10 Impervious = J. C= 0.85 Weighted C= Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 = 0.35 crs 1100=3.10 in/hr Q100='0.48cf., 5/22/2012 V100 87 r:.. Thompsons Rule (1" per hour) I = 1.0 in/hr (100 -yr Return Period, Duration = 60 min.) Q = 0.16 efs (Q at 60 min.) V = 566 c.f. L 19 ft Vr= 1,-E97t.'. Vk= 851 c.f. 567 c.f. System Size W-7ft D=9.0ft_ volume of drain rock provided void volume provided percolation volume provided total storage volume provided by seepage bed Time to Empty . G}._yn t c --_. ._.,,-•`F -. -. ....... .: _ _...... a .-.ymvklw -. nmTG I k = 8.0 in/ percolation rate hs s time to drain required storage volume S&G Trap Check Vault Size - jOldcastle New 1000 gal. Number of units- 11 Baffle Area/unit - 17.08 s.f. Drainage Area, 1A= 7,991s.f. Max Flow= rI. 21 cls _.aE77 fps OK-kY Site Planning - Landscape Architecture- Civil Engineering -Golf Course Irrigation & Engineering - Graphic. Design - Surveying 462 E. Shore Drive, Suite 100 ..Eagle, Idaho 83616 - P 208.939.4041 - F 208.939.4445 - www.thelandgroupinc.com Village Center (PN 111049) Storm Drainage Calculations Drainage Area Characteristics; Area 12 (Bldg AB -100) Total A= 10,225 s.f. Pervious = s.f. C= 0.10 Impervious C= 0.85 Weighted C Tc= 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 =r'= 1100 = 3.10 in/hr Q100 = 0167 n V25 V100 5/22/2012 Thompsons Rule (1" per hour) I = 1.0 in/hr (100 -yr Return Period, Duration = 60 min.) Q = 0.20 cfs (Q at 60 rain.) V = 724 c,C L= 25 ft Vr= ib575 cA, Vv=530CJ, Vk= 11.7cti. 747 c.f. Vtotal> V100? • System Size W=7ft D=9.0fl volume of drain rock provided void volume provided percolation volume provided total storage volume provided by seepage bed Time to Empty k= 8.0 in/hr percolation rate time to drain required storage volume S&G Trap Check Vault Size= jOldcastle New 1000 gal Number of units- RE BaffleArea/unit = 7.08 0. Drainage Area 1A - 10,225 s.f. Max Flow =F 0K -NY • o r 'a':3 Site Planning -Landscape Architecture - Civil Engineering • Golf. Course Irrigation & Engineering - Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 � P 208.939.4041. • F208.939.4445 • www.thelandgroupinc.com Village Center (PN 111049) 5/22/2012 Storm Drainage Calculations Drainage Area Characteristics: Area 13 Total A= 128,100 s.f. Pervious = s.f. C= 0.10 Impervious = C= Q85 Weighted C = 0. Tc = 10 min. Rational Method/Triangular Hydrograph 125 = 2.25 in/hr Q25 1100 = 3.10 in/hr Q100 li- V100 Thompsons Rule (1" per hour) I= 1.0 in/hr (100 -yr Return Period, Duration = 60 min.) Q ISOrfs (Q at 60 min.) System Size L = 89 ft W = 24 ft D = 9.0 ft Vr 9,224 r..f. volume of drain rock provided Vv = 7? 690 c,f. void volume provided Vk „424 c.f, percolation volume provided 0,114 r'f. total storage volume provided by seepage bed I, Vtotal> V100? • Time to Empty =mss. . k - 8.0 in/hr percolation rate IsA = s time to drain required storage volume S&G Trap Check VaultSize - Oldcastle New 1000 gal. Number of units - 3 Baffle Area/unit - 7.08 s.f. Drainage Area 1A _ 1128,100 s.f. Max Flow 5.15 - o0, w„=. iii^ OKAY Site Planning - Landscape Architecture - Civil Engineering Golf Course Irrigation & Engineerings• Graphic Design - Surveying 462 E. Shore Drive, Suite 100 - Eagle, Idaho 83616 - P 208.939.4041 - F208.939.4445-www.thelandgroupinc.com May 22, 2012 Appendix C Geotechnical Report for Reference AF Site Planning -Landscape Architecture •Civil Engineering -Golf Course Irrigation & Engineering -Graphic Communication •Surveying 462 E. Shore Drive, Ste. 100, Eagle, Idaho 93616 • P 205.939.4041 F 20$.939.4445 • www.thelandgroupinc.com