HomeMy WebLinkAboutMeridian Town Center - Village Center Development - Storm Water Management - Engineering Drainage Reporti� Ow Act;
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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
The Land Group, Inc.
Jason Densmer, PE
462 East Shore Drive
Eagle, Idaho 83616
Ph: 208.939.4041
Fax: 208.939.4445
Project No. 111049
J
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 prior to 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.
Appendix A
Site Drainage Areas
Ej
May 22, 2012
May 22, 2012
Appendix B
Drainage Calculations
or
Village Center (PN 111049)
Storm Drainage Calculations
Drainage Area Characteristics: Area 1 (Bldg AG -100)
Total A= 9,450 s.f.
Pervious = s.f. _
Impervious = 9,450 s.f.
Weighted C = 1.00
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 0.49 cfs
1100 = 3.10 in/hr Q100 = 0.67 cfs
V25 = 391 c.f.
V100 = 539 c.f.
Thompsons Rule (1" per hour)
Q = 0.22 cfs
V = 788 c.f.
5/22/2012
System Size
L= 21ft W= 9ft D= 9.0 ft
Vr = 1,701 c.f.
VV = 680 c.f.
Vk = 126 c.f.
806 c.f.
i OKAY
k= 8.0in/hr
4.3 h rs
Time to Empty
S&G Trap Check
Vault Size =
Oldcastle New 1000 gal.
Number of units=
1
Baffle Area/unit =
7.08 s.f.
Drainage Area 1A =
9,450 s.f.
Max Flow =
0.67 cfs
- .
0.09 fps
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 2
Total A= 80,981 s.f.
Pervious = s.f.
Impervious = 80,981 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 3.56 cfs
1100= 3.10 in/hr Q100 = 4.90 cfs
V25 = 2,848 0.
V100 = 3,924 c.f.
Thompsons Rule (1" per hour)
= 1.0 in/hr
Q= 1.58 cfs
V = 5,736 c.f.
System Size
L= 90 ft W= 15 ft
Vr= 12,150c.f.
Vv = 4,860 c.f.
Vk = 900 c.f.
• 5,760 0.
07335
Time to Empty
k = 8.0 in/hr
4.4 hrs
S&G Trap Check
Vault Size = Oldcastle_New 1000 gal.
Number of units= 2 ---
Baffle Area/unit = 7.08 s.f.
Drainage Area 1A = 180,981 s.f.
Max Flow= 4.90 cfs
0.35 fps OKAY
5/22/2012
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.
Impervious= 179,312 s.f.
Weighted C = 0.85
Tc = 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 7.87 cfs
1100 = 3.10 in/hr Q100 = 10.85 cfs
V25 = 6,306 0.
V100 = 8,688 c.f.
Thompsons Rule (1" per hour)
I= 1.O in/hr
Q = 3.50 cfs
V = 12,701 c.f.
L = 200 ft
Vr = 27,000 c.f
Vv = 10,800 c.f
Vk = 2,000 0.
=12,800 0
Vtotal >_ V100? •
k = 8.0 in/hr
!.M4.3 hrs
5/22/2012
Time to Empty
S&G Trap Check
Vault Size= Oldcastle New 1000 gal.
Number of units= i4
Baffle Area/unit = 17.08 s.f.
Drainage Area 1A = 179,312 s.f.
Max Flow = 10.85 cfs
INIff1 .. 038 f;is OK_AY
D = 9.0 ft
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 4
Total A= 83,445 s.f.
Pervious = s.f.
Impervious = 83,445 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 3.66 cfs
1100 = 3.10 in/hr Q100 = 5.05 cfs
V25 = 2,935 c.f.
V100 = 4,043 c.f.
Thompsons Rule (1" per hour)
I= 1.0 in/hr
Q = 1.63 cfs
V = 5,911 c.f.
System Size
L=93ft W=15ft D=9.0ft
Vr= 12,555 c.f. voiui� _j . „ �rv.iJ__I
Vv= 5,022 c.f. void vchlrra -> ,i -J
Vk = 930 c.f. oercolarion vDlu;ne provid2d
5,952 c.f. totol ;tororge voluixe provided by 52epcg2 bed
MOKAY
Time to Empty
k = 8.0 in/hr
�4.3 hrs J cto J':oht re
S&G Trap Check
Vault Size = Oldcastle New 1000 gal._ I
Number of units= 2
Baffle Area/unit = ,7.08 s.f.
Drainage Area 1A = 183,445 s.f.
Max F�loww= 5.05 cfs
7llii 0.36 fps 01L
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 5
Total A= 148,997 s.f.
Pervious = s.f.
Impervious= 148,997s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 6.54 cfs
1100 = 3.10 in/hr Q100 = 9.01 cfs
V25 = 5,240 c.f.
V100 = 7,219 c.f.
Thompsons Rule (1" per hour)
I= 1.0 in/hr Gu, " ,
Q = 2.91 cfs
V = 10,554 c.f.
System Size
5/22/2012
L= 191ft W= 13ft
Vr= 22,347 c.f. 10h, Iiic c_j d,a,n, c'lk LY0.rdefj
Vv= 8,939 c.f. void volume,orovided
Vk = 1,655 c.f. m2 pros; W'ed
10,594 c.f. ��j voitime provjded bw seap,oge bed
OKAY
Time to Empty
k= 8.0in/hr
!-a 4.4 Inrs
S&G Trap Check
Vault Size = iOldcastle New 1000 gal.
Number of units = 13
Baffle Area/unit = 17.08 s.f. _
Drainage Area 1A = 148,99_7 s.f_
Max F�loww= 9.01 cfs
1171!'ii 0.42 fps
1 WE
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.
Impervious = 267,835 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 11.76 cfs
1100 = 3.10 in/hr Q100 = 16.20 cfs
V25 = 9,419 c.f.
V100 = 12,978 c.f.
Thompsons Rule (1" per hour)
I= 1.O in/hr
Q = 5.23 cfs
V = 18,972 c.f.
L = 343 ft
Vr = 40,131 c.f.
Vv = 16,052 c.f.
Vk = 2,973 c.f.
=19,025 c.f.
Vtotal >_ V10O? •
5/22/2012
Time to Empty
k = 8.O in/hr —
4.4 hrs
S&G Trap Check
Vault Size = Oldcastle New 1000 gal.
Number of units = 115
Baffle Area/unit .7.
=
08 s.f.
Drainage Area 1A = 267,835 s.f.
Max Flow = 16.20 cfs
0.46 fps 5"
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
Total A= 64,511 s.f.
Pervious = s.f.
Impervious = 64,511 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 1n/hr Q25 = 2.83 cfs
1100 = 3.10 in/hr Q100 = 3.90 cfs
V25 = 2,269 c.f.
V100 = 3,126 c.f.
Thompsons Rule (1" per hour)
= 1.0 in/hr (!X -p -, i a. -'u
Q = 1.26 cfs (4 "r 50 trm j
V = 4,570 c.f.
System Size
L=135 ft W=8ft
Vr = 9,720 c.f.
Vv = 3,888 c.f.
Vk = 720 c.f, 0v;ded
4,608 0. e volume gravid? -1 by 5eep09e bed
r OKAY
Time to Empty
k = 8.0 in/hr
a 4.3 In rs
S&G Trap Check
Vault Size = iOldcastle New 1000 gal.
Number of units = I2 _
Baffle Area/unit = 17.08 s.f.
Drainage Area 1A = 164,511 s.f.
Max Flow= 3.90 cfs
0.28 fps OKAY
D=9.oft�
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 = s.f.
Impervious = 44,450 s.f.
Weighted C = 0.85
Tc = 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 1,95 cfs
1100 = 3.10 in/hr Q100 = 2.69 cfs
V25 = 1,563 c.f.
V100 = 2,154 c.f.
Thompsons Rule (1" per hour)
1 = 1.0 in/hr
Q = 0.87 cfs
V = 3,149 c.f.
System Size
L=74ft W= loft
Vr = 6,660 c.f.
Vv = 2,664 c.f. _ d
Vk = 493 c.f.
ZZ 3,157 c.f.
OKAY
Time to Empty
k = 8.0 in/hr
9Z 4.4 In rs
S&G Trap Check
Vault Size = 'Oldcastle New 1000 gal.
Number of units= 2 _
Baffle Area/unit = 7.08 s_f. _
Drainage Area 1A = 1,44,450 s.f. _
Max Flow = 2.69 cfs
0.19 fps
5/22/2012
D = 9.0 ft
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. _
Impervious = 299,250 s.f.
Weighted C = 0.85
Tc = 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 13.14 cfs
1100= 3.10 in/hr Q100 = 18.10 cfs
V25 = 10,524 c.f.
V100 = 14,500 c.f.
5/22/2012
Thompsons Rule (1" per hour)
I= 1.0 in/hr
Q = 5.84 cfs
V = 21,197 c.f.
L= 178 ft
Vr = 44,856 c.f
Vv = 17,942 c.f
�
Vk = 3,323 c.f.
'=21,265 c.f
Vtotal >_ V100? •
k = 8.0 in/hr
4.4 hrs
System Size
W=28ft D=9.0ft
%o;il vol�;r^= provded
oerr_olalion vohime prov;tfId
toted starage voh;me provided b+; ,=epc,�ge bed
Time to Empty
S&G Trap Check
Vault Size = Oldcastle New 1000 gal. (2-1500 gal.)
Number of units= 5
Baffle Area/unit = 7.08 s.f.
Drainage Area 1A = '299,250 s.f.
Max Flow = 18.10 cfs
0.46 fn; 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 10
Total A= 326,703 s.f.
Pervious = s.f.
Impervious = 326,703 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 14.34 cfs
1100 = 3.10 in/hr Q100 = 19.76 cfs
V25 = 11,489 c.f.
V100 = 15,830 c.f.
Thompsons Rule (1" per hour)
= 1.0 in/hr 00-y urr
Q = 6.38 cfs Q 7t 60 min j
V = 23,141 c.f.
L= 320 ft
Vr = 48,960 c.f
Vv = 19,584 c.f
Vk = 3,627 c.f.
ZZ 23,211 c.f
Vtotal >_ V1007 •
k= 8.0in/hr
ffl 4.4 hrs
5/22/2012
System Size
W= 17ft D= 9.0 ft
VUiu1P,C Df u', Jul 1vi,�< Pi Dv,�.-
void volume provided
percolation volume provided
total;_•�igevolumeprjs,I;J
Time to Empty
S&G Trap Check
Vault Size = I Oldcastle New 1000 gal.
Number of units= I6 _ _
Baffle Area/unit = 7.08 s.f.
Drainage Area 1A = 326,703 s.f. T J
Max Flow = 19.76 cfs
0.47 fps O[LvI"
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 11 (Bldg AD -100)
Total A= 7,991 s.f.
Pervious = s.f.
Impervious = 7,991 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 0.35 cfs
1100 = 3.10 in/hr Q100 = 0.48 cfs
V25 = 281 c.f.
V100 = 387 c.f.
5/22/2012
Thompsons Rule (1" per hour)
1=1.Oin/hr `�;rr, JDu,a���,�=5;min.J
Q = 0.16 cfs Q at 60 min. )
V = 566 c.f.
System Size
L=19ft W=7ft
Vr= 1,197c.f.
Vv = 479 c.f.
Vk = 89 c.f.
ME 567 c.f.
OKAY
Time to Empty
k = 8.0 in/hr
sH 4.4 h rs
S&G Trap Check
Vault Size = Oldcastle New 1000 gal.
Number of units= 1
Baffle Area/unit = 17.08 s.f.
Drainage Area 1A = 17,991 s.f.
Max Flow= 0.48 cfs
0.07 fps Ot 1Y
D= 9.O ft
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.
Impervious = 10,225 s.f.
Weighted C = 0.85
Tc = 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 0.45 cfs
1100 = 3.10 in/hr Q100 = 0.62 cfs
V25 = 360 c.f.
V100 = 495 c.f.
Thompsons Rule (1" per hour)
I= 1.0 in/hr
Q = 0.20 cfs
V = 724 c.f.
System Size
5/22/2012
L=25ft
W=7ft D=9.0ft
Vr = 1,575 c.f.
Vv = 630 0.
c ovird-J
Vk= 117 c.f.
;olumeprovi0�a
747 0.
eotoi storog_= ✓otume provirlecl s ;=_ _ , _ _a•.1
.. �WOKAY
Time to Empty
k=8.0in/hr
_ ----- '-
4.2 hrs
S&G Trap Check
Vault Size = IOldcastle New
1000 gal.
Number of units= 1
Baffle Area/unit = 7.08 s.f.
Drainage Area 1A = 10,225 s.f.
Max Flow = 0.62 cfs
- . 0.09 fps
OILS'
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 13
Total A= 128,100 s.f.
Pervious = s.f.
Impervious= 128,100 s.f.
Weighted C = 0.85
Tc= 10 min.
Rational Method/Triangular Hydrograph
125 = 2.25 in/hr Q25 = 5.62 cfs
1100 = 3.10 in/hr Q100 = 7.75 cfs
V25 = 4,505 c.f.
V100 = 6,207 c.f.
Thompsons Rule (1" per hour)
1 = 1.0 in/hr
Q = 2.50 cfs n
V = 9,074 c.f.
System Size
L=89ft W=24ft D=9.0ft
Vr = 19,224 c.f.
Vv = 7,690 c.f.
Vk = 1,424 c.f.
M 9.114 c.f.
OKAY
Time to Empty
k = 8.0 in/hr
M 4.4 h rs
S&G Trap Check
Vault Size = Oldcastle New 1000 gal.
Number of units= 3 _
Baffle Area/unit = 7.08 s.f.
Drainage Area 1A = 1128,100 s.f.
Max Flow = 7.75 cfs
11111MUNTEIR Mg 0.36 fps ()K'\)
-
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
May 22, 2012
Appendix C
Geotechnical Report for Reference
ct
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m
LU
Area
9.450
Fairview Avenue 7.991 sf 10,225 sf
Onsite Storm Drainage Tributary Areas
10RIZONTAL SCALE: 1' = 150'
V.
THE LAND GROUP
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THE LAND GROUP
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THE LAND GROUP
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