HomeMy WebLinkAboutVerraso Village Storm Drainage Calc STORM DRAINAGE
CALCULATIONS FOR:
•
VERRASO VILLAGE
Meridian, Idaho
July 13, 2015
AS PREPARED BY:
Intermountain Engineering
2587 SouthSide Blvd..
Melba, Idaho 83641
(208) 941-1245
oF
1
.
CALCULATIONS
FLOW CALCULATIONS
Flow nd volume for the basin areas were calculated using the Rational Method. The"C"coefficient used in the
calcul tions is based on weighted values as shown. Since historical drainage is not available, a 100-yr event is
exami ed.
PIPE IZING AND HYDRAULIC GRADE CALCULATIONS
These calculations employ the Manning Equation.The hydraulic grade is based on calculated flow and selected
pipe si e.
DETE TION VOLUME CALCULATIONS
Since .n outfall is not provided, detention volume is based on the rational method using the 100 year storm over
the wo st case time of concentration& 1 hour 100 year storm.
POND VOLUME CALCULATIONS
The p• d volume calculations are based on an average of the water surface area and the pond bottom area,
applie. over the design pond depth.
GENE"AL NOTES
Runoff ater will enter the drop inletrs after being collected and flowing in the gutter plate. Water then flows
throug a sand and greese trap before entering the sepage bed.All water will be retained on site and percolate
into th'- underlying soils.There will be no discharge off site.
EQUATIONS USED IN CALCULATIONS
RATIONAL METHOD
Q=CiA where: Q=Runoff Rate, cfs
C=Runoff Coefficient
i=Storm Intensity, in./hr.
A=Basin Area(s), acres
MAN ING EQUATION
V=1.49R2/3S1'2/n where: V=Velocity,fps
R=Hydraulic Radius,ft.
S=Channel Slope,ft./ft.
n=Manning Roughness Coefficient
PERC.LATION VOLUME(SCS TRIANGULAR UNIT HYDROGRAPH METHOD)
V=(Area)(Perc. rate)(t)/(12)(60)
where: V=Volume,cu.ft.
Area=Infiltration bed area, sf
Perc. rate=percolation rate, in/hr
t=worst-case duration, min.
ORIFI'E EQUATION
Q=(Coefficient)(3.1416 x Radius2)(64.4 x Head)"
where: Head=W.S.E.-Center of Orifice
=81.50-78.14
=3.4'
OTHE- EQUATIONS USED
Q=VA where: Q=Flow, cfs
V=Velocity,fps
A=Cross Sectional Area,sq.ft.
... Appendix D
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1
INTERMOUNTAIN ENGINEERING
2587C Southside Blvd. Verraso ViAage
Me ba,Idaho 83041
(201)941-1245 (FAX)495-2409 Meridian,Idaho
DATE 7/13/2015
PRI.DEVELOPED FLOIA AND VOLUME CALCULATION(Area 1
__- FILE: Verraso PAGE
The weighted runoff Coefficient for the developed site Is calculated.
•
C c RUNOFF COEFFICIENT(EXIBIT"B"Recommended"C"Coefficients for"Rational
Method Equation"-Peak Rate of Discharge)
•
Cu=UNIMPROVED AREA RUNOFF COEFFICIENT
=0.10
Cd=DEVELOPED SINGLE FAMILY RESIDENTIAL RUNOFF COEFFICIENT
=0,50 (or use calculated(weighted)value If Ngher)
_ BLDG&PAVED ACRES(0.95)+LANDSCAPED ACRES(0.10)
TOTAL ACRES
0.417 •(0.95)+ 0.235 •(0.10)
_--- 0.052 0.04
PRE-DEVELOPED FLOW ND VOLUME CALCULATIONS
The pre-developed flow for a project site and the upstream area from the slte are calculated using
the Rational Method.The t e of concentration Is based on overland flow to a point of channelization
and then the travel lime in t e existing channel to the downstream end of the concerned area.
The pre-developed volume I calculated using the SCS Triangular Unit Hydrograph.Pre-developed
volume and flow are based•.n the 100-year storm event and site caracterlstics.
Note the basin area is only ccounting for the area of the basin that we will be able to discharge from.
BASIN CHARACTERISTICS
BASIN AREA 000 acres
OVERLAND'LOW LENGTH= 345.00 feet
OVERLAND LOPE= 1.21%
RUNOFF CO FFICIENT(C)= 0.10
, FLOW AND VOLUME CALOULATtON RESULTS
OVERLAND IME OF CONCENTRATION
• . - 100 YEARS •RM INTENSITY(i)= 31.4 min
1.57 INhr
100 YEAR Pa K FLOW(0)=
000 Ms NO DISCHARGE
100 YEAR VO UME(from SCS triangular Lend hydrograph)=
- of
sea TRIANOULAR UNIT HYOR00RAPR
l �Vo&DEVELOPEo FLOW
09
OB
O6
Z 05
e cc
OJ
01
00
00 i00 000 00.0 400 500
rum 6s.5 tooev5 eco
era
II
INTERMOUNTAIN ENGlF EERING
2507C Southside Blvd. Verraso Village
Melba,Idaho 83841
(206)941-1245 (FAX)495-2469 Mandan,Idaho
DATE 7/13/2015
_—._–_--_---_.--_—_—_–"_--
POST-DEVELOPED FLOW AND VOLUME CALCULATIOP Area 1 ---
-------- – FILE: SECURITY PAGE
flow
or
basin areas are also
lcated using the Rational Method.The
time of concent ati n la ba ed on a comb)atin offllot to street time,gutter time and applicable '—
pipe.time prior to reaching the retention area.The lot time is calculated using
Mar,ning's kinematic notch' (Overton and Meadows 1978).This equation Is also used for sheet
flow of less than 300 feet he gutta time Is calculated using the travel length along the gutter
and the gutta velocity at lb design slope. Pipe time Is calculated using the pipe travel length
and an average pipe veloci calculated using manings formula.
STORM RETURN PERIO =100 YEAR
BASIN CHARACTERISTIC
BASIN AREA
2 YEAR 24 HOUR RAINFALL(In)= 0.852 acres
1.20 In
• OVER GRASS FLOW TO CURB 8 GUTTER
LOT SLOPE- 100.00 feet
MANNING'S q FOR GRASS= 0.01 FT/FT
0.24
VALLEY GU ER=
GUTTER FL W LENGTH=
GUTTER SL PE= 143.00 feet
MANNING'S FOR CURB=
0.018 0'018
PIPE LENGT =
PIPE DIAMET R= 24 N
PIPE SLOPE 12 IN
MANNING'S ri (w
FOR PIPE= 0' 3
0.0113
AVERAGE PI E VELOCITY=
RUNOFF CO FFICIENT(C)= 1.94 ec
0.64 (weighted)
FLOW AND VOLUME CALCilLATION RESULTS
,
LOT TRAVEL TIME= 307 min.
GUTTER TRAVEL TIME=
PIPE TRAVEL IME= 2.5 min.
02 min. Method 1 Method 2
OTAL TIME uses Tc , 0 yr Tc
100 YEAR ST RM INTENSITYOF(I)=CONCENTRATION 33.4 min 1hr1080.00 min
1.50 liVhr 1.00 in/hr
100 YEAR P KFLOW(0)=
0.83 cfs 0.42 cfs
100 YEAR VO I ME(from SCS triangular unit hydrograph)=
1,883 of 2,017 cf
acs TRIANGULAR UNIT HYDROORAPH
a' svEtoerto naw
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TM(mini hero 9ne logo
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1
INTERMOUNTAIN ENGINEERING
25/17C Southside Blvd. I Verraso Village
Me'ba,Idaho 83841
(208)941-1245 (FAX)495-2469 Meridian,Idaho
--- .—_— DATE 7/13/2015
DETENTION/RETURN V LUME CALCULATIONS Area 1 ------ •-__-___
-- FILE: Verraso PAGE
The method calculates theIrequired detention volume by subtracting the calculated `
pro-developed volume hors1✓the post-developed SCS Triangular Unit Hydrograph.Then the
volLme is increased by 15 percent to compensate for detention volume losses due to
sed meet between maintenance periods.
STORM RETURN PERIOC=100 YEAR
UNIT HYDROGRAPH METHOD
PRE-DEVE4:1PED SITE DISCHARGE= 0.00 cfs
POST-DEVELOPED VOLUME= 2 017 cf (worst case design)
(worst case design)
SCE TRIANGULAR UNIT HYDROORApl4
—acmr.oE n_oprnrlov I
as
1o !
3
�as
0 0
250 30.0 450 50 e .
aoo 2se eoa soo
. .•
. TINS 1.51ICC o
DETENTION VOLUME REQUIRED=
15%VOLUME FOR SEDIMENT= 2017 cf
TOTAL VOLUME REQUIRED= 231939 of
of
PONVOLUME CALCULATI
[) IONS
i
Thep and volume calculation are based on the equasion s Also Included in this section are
infiltration bed calculations.I filtration bed volume calculations are based on veld space
in the drain rock and percdat on volume which occurs over the time base for the
post-<eveloped SCS Triangu r Unit Hydrograph. If infiltration beds are not used,then only the
pond bottom percolation is sidered.
REQUIRED DETENTION= 1 2319 of
I
PONE VOLUME CALCULAT ON
POND BOTTOM AREA= 0.00 sf
POND WATER SURFACE AREA=
POND TOP BK ELEV= 0.00 sf
�
POND WATE SURFACE ELEV= 0'00 R
POND INVER1 ELEV= 0'00 R
SEASONAL G OUND WATER= O.00 R
I 2817.00 Testhde showed no water at 10 BELOW GROUND
OND FREEBOARD= 000 R
I VERT TO GROUND H2O= -2817.00 R
OND DEPTH= 000)1
OND STORAGE=
0.00 of
INFILTRATION BED CALCU TION
INFILTRATION BED BOTTOM AREA= I -
INFILTRATION ED DEPTH= 510'00 sf (entire bottom) -
VOID SPACE I DRAIN ROCK= 7.400 ft
PERCOLATIO RATE= 40%
8.00 in/hr
VOLUME IN VOIDS= 1428.00 cf
PERCOLATION VOLUME= 908 cf
IFFILTRATION STORAGE=
2338 cf
TOTAL DETAINED VOLUME= 2338 cf
5. 231
THEREFORE STORAGE ISCADEQUATE
.
IM-ERMOUNTAIN ENGIF EERING
25337C Southside Bbd. 1 Verreso Village
Melba,Idaho 83641
(2L8)941-1245 (FAX)495-2469 Meridian,Idaho
---- DATE 7/13/2015
PRE-DEVELOPED FLO AND VOLUME CALCULATION:Area I --- —
— -- FILE: SECURITY PAGE —_--`^
_----
TIME REQUIRED TO DIS'IPATE VOLUME
TIME CALCULATION ASSUMES A DISCHARGE OFFSITE
EQUAL TO THE CALCULATED PRE-DEVELOPED FLOW OF I
CFS AND PERCOLATION OVER THE POND BOTTOM AREA 0.00
1 EQUAL TO B in./hr.
TIME= 6.82 hours
GUTTER FLOW CALCULATIONS
POST-DEVELOPED RUNC4FF COEFFICIENT(C)=
LOT TRAVEL TIME= 0.64
30.7 min
f DROP INLET CAPACITIES: VERTICAL CURB=
3.25 cfs(depth at top of curb)
ROLLED CURB= 3.15 cfs(depth al top of curb)
Sub-Basin Areas for the different catch basins are calculated using the design drawings.
Pipe sizing and hydraulic grade caculalions.
Thele calculations employ the Manning Equation combined with flow entering the pipe.The
hydraulic grade is based onbredetmnined flow and pipe size.
Location AREA DATA
SUfi-BASW SUB-BASINCURB GUTTER AVERAGE GUTTER GUTTER TOTAL
CALCULATIONS
<,RFA AREA TYPE LENGTH GUTTER TME CAPACITY TIME 2 100yr
(V•R) R SLOPE min I Q I o
1.00 0.85 113 R °h Te Mohr ch InMr
0.40°.6 1.5 1.54 32.3
1.14 1.54 r 0.84
•
1
• INTERMOUNTAIN ENGII.EERING
25117C Southolde Blvd. Vemaso Village
Melba,Idaho 83641 1
(208)941-1245 (FAX)495.2469 _-----`Medan•Idaho
�`"— --- DATE 7/13/2015
SAND AND GREASE TRAfP CALCULATIONS Area 1 —" --PAGE --
_ FILE: SECURITY PAGE
The sand and grease trap(t)were sized based on the post-developed flow draining to them The ---_-'
thrcat width is calculated wlh this flow and a maximum velodty of 0.5 fps through the throat.
SOD MENT/GREASE TRAP SIZING 1500 gal
NUMBER OF TANKS -
DISCHARGE`CFS) Use zero(0)1500 sag
VELOCITY-MAXIMUM(FPS) 0.58
0.50
REQUIRED THROAT AREA(SF) #D1
SF) ><IVIG
TANK SIZE I ( 1 5001
TANK WIDTH'(FT) 1,500
525
THROAT-WI(H(in) /DIV/01
VELOCITY-A TUAL(fps) BDIV/01
SO ENT/GREASE TRAP SIZING 1000 gal
NUMBER OF TANKS 1
DISCHARGE FS) Use on.(1)1000 sag
VELOCITY-M MUM(FPS) 0.40
REQUIRED ROAT AREA(SF) 050
TANK SIZE( 0 0.96
TANK DiH((FT) 1,000
MYTHTHROAT WIDTH On)
1.00
VELOCITY-ACI UAL(fps) /1
0.13
PIPE SIZING CALCULATIONS _
POS"-DEVELOPED RUNOFF COEFFICIENT(C)=
0.84
LOT TRAVEL TIME= 30.
AVEFIAGE PIPE FLOW VELOCITY= 30.7 min
1.84 fUsec
FLOWRATE CALCULATIONS
La:atlan AREA DATA
PIPE CONTRIB. ' CURB GUTTER GUTTER CALCULATIONS
a AREA ( TYPE PIPE GUTTER PIPE TOTAL
LENGTH SLOPE LENGTH TIME2 r
RinTIME TIME
AC (V,R)
8 R I O
1,-1 0.65 R 143 0.40% 24 1.1 min Tc In41f ch
02 320 1.08 0.44
PIPE SIZING CALCULATIOI r P-1
II IPE DIAMETER.
IPE SLOPE 12 IN
JJJTTT•••"ANNING'S N FOR PIPE. 0.0022 NR min.
FLOWRATE 0.013
APICITY OF PIPE FLOWING FULL 0.44 ch
1.67 cfs PIPE SIZE IS ADEQUATE
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SII
INTERMOUNTAIN ENGII,EERING
251.7C Southside Blvd. Verraso Village
Melba,Idaho 83641
(201)941-1245 (FAX)495-2489 Meridian,Idaho
DATE 7/13/2015
PRE-DEVELOPED FLOW FILE:AND VOLUME CALCULATION;Area 2 --
-------- __ E: VERRASO PAGE "-------
The weighted runoff Coefficient for the developed site is calculated. --_ -- -- ------.--__._—
C e RUNOFF COEFFICIENT(EXIBIT"B"Recommended"C"Coefficients for"Rational
Method Equation'-Peak Rate of Discharge)
Cu=UNIMPROVED AREA RUNOFF COEFFICIENT
= 0.10
Cd=DEVELOPED SINGLE FAMILY RESIDENTIAL RUNOFF COEFFICIENT
= 0.50 (or use calculated(weighted)value if higher)
BLDG&PAVED ACRES(0.951 F LANDSCAPED ACRES(0.20)
TOTAL ACRES —"-- -----
I
1.02 •(0.95)u 0.61 •(0.10)
•
. 1.63 '--"a 0.63
PRE-DEVELOPED FLOW.,ND VOLUME CALCULATIONS
The Fre-developed now for tie project site and Ike upstream area from the site are calculated using
the Rational Method.The 1' a of concentration Is based on overland flow to a point of chenneliaation
and then the travel lime In th6 existing channel to the downstream end of the concerned area.
The pre,developed volume 7 calculated using the SCS Triangular Unit Hydrograph.Pre-developed
volume and flow are based on the 100-year storm event and site caracterisfics.
Note the basin area is only amounting for the area of the basin that we will be able to discharge from.
BASIN CHARACTERISTICS
BASIN AREA 1.63 ones
OVERLAND F OW LENGTH= 680.00 feet
OVERLAND S OPE= 1.00%
RUNOFF CO FFICIENT(C)= 0.10
i 2.00
FLOW AND VOLUME CALC��'I1LATION RESULTS
OVERLAND TI c1E OF CONCENTRATION
100 YEAR ST RM INTENSITY(i)= 48.9 min
1 1.17 in/hr
100 YEAR PEAK FLOW(0)=
0.00 cls No discharge
100 YEAR VO UME(from SCS triangular unit hydrograph)=
- c1
SCS lama u asEOE�Ee�reLCPy
lamas
ROM
E
0.6
i an
8 0.
. 'i
0.1
001 00 700 400 a<wry e00 1030 1700
600 ruo0
•
•
.
INTERMOUNTAIN ENGINEERING
2587C Southside Blvd. Verraso Village
Melba,Idaho 83841 I
(2011)941-1245 (FAX)495-2489 Meridian.Idaho
DATE 7/13/2015
POST•DEVELOPED FLOW AND VOLUME CALCULATION Area 2 _
FILE: SECURITY PAGE 4
.Posl-devdoped flow far the1basin areas are also calculated using the Rational Method.The —'
time of concentration is based on a combination of lot to street time,gutter time and applicable
pipe time prior to reaching the detention pond area. The lot time Is calculated using
Manning's kinematic solution(Overton and Meadows 1978).This equation is also used for sheet
flow of leas than 300 feel. he gutter time is calculated using the travel length along the gutter
and the gutter veloc8y at thf design slope. Pipe time Is calculated using the pipe travel length
and:m average pipe vetodt,calculated using manings formula.
STORM RETURN PERIOD'.
100 YEAR
BASIN CHARACTERISTICS
BASIN AR
2 YEAR 24 H UR RAINFALL(in)= 1'83
1.20 in in
LOT DISTAN E TO STREET=
LOT SLOPE t0 CURB= 100.00 feet
MANNING'S 4 FOR LOT= 0.01 FT/FT
0.24
CURB TYPE rob,vert)= ROLL
GUTTER FLOW LENGTH=
GUTTER SL(PE= 1050 feet
MANNING'S FOR CURB= 0.054
0.01818
PIPE LENGT • 357 fed
PIPE DIAMET R=
PIPE SLOPE 12 IN
MANNING'S n FOR PIPE= 0.0022
0.013
AVERAGE PI E VELOCITY=
1.94 ft/sec ,
RUNOFF CO FICIENT(C)=
0.83 (weighted)
FLOW AND VOLUME CALC CATION RESULTS
'' LOT TRAVEL{'IME. 30.7 min.
'' GUTTER TRAVEL TIME= 2.8 min.
PIPE TRAVEL'ME.. 3.1 min.
Method 1 Method 2
OTAL TIME OF CONCENTRATION uses To iM.100 yr Tc
100 YEAR STARM INTENSITY(I)= 38.8 min 80.00 min
in/hr 1.00 In/hr
100 YEAR PFLOW(q)c
EA
1.44 cfs 1.03 efs
100 YEAR VOL ME(from SCS triangular unll hydrograph)=
4,229 of 4,950 M
' ---__fC$11tIANOULA,R UNIT HYOROORA►R
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I
INTERMOUNTAIN ENGINEERING
25117C Southside ONd. i Verraso Village
Me ba.Idaho 83541
(209)941-1245 Meridian,Idaho
(FAX)495-2469
'----------------__ __ _ DATE 7/13/2015
DETENTION/RETURN VOLUME CALCULATIONS Area 2 _ — ----- ----------
{( _ FILE VERRASO PAGE
The method calculates the Fequked detention volume by subtracting the calculated
pre-developed volume Rom}the post-developed SCS Triangular Unit Hydrograph.Then the
volume is increased by 15 percent to compensate for detention volume losses due to
sediment between maintenance periods.
STORM RETURN PERIOD=100 YEAR
UNIT HYDROGRAPH METHOD
I
PRE-DEVELOPED SITE DISCHARGE= 0.00 cfs
POST-OEVELOPED VOLUME_ (worst case design)
4,950 of (worst case design)
SCS TRIANGULAR UNIT HYDROGRAPH -
14 1
04 i
000]00 , )0.0 X00 \
c0.0 BOO ima
i TMs 1.1dalo
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DETENTION VOLUME REQUIRED= 4950 cf
15%VOLUME FOR SEDIMENT= 743 cf
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TOTAL VOLUME REQUIRED= 5693 cf
PON()VOLUME CALCULAT)ONS
The pond volume calculationare based on the equasion s Also included in this section are
infikration bed calculations.I filtration bed volume calculations are based on void space
in the drain rock and percolation volume which occurs over the time base for the
post-c eveloped SCS Triangular Unit Hydrograph. If infiltration beds are not used,then only the
pond bottom percolation is co tsidered.
REOL IRED DETENTION= i 5693 cf
PONC VOLUME CALCULAT N
POND BOTTO AREA= 0.00 sf
. . POND WATE SURFACE AREA= 0.00 sf
POND TOP B K ELEV= 0.00 1t
POND WATER SURFACE ELEV= 000 R
POND INVERTT��ELEV= 0ft
00
SEASONAL GFOUND WATER= 2617.00
OND FREEBOARD= 0.00 R
INVERT TO GROUND H20= -2817.00 ft
POND DEPTH= 000 R
POND STORAGE=Vol=h/31(a*A+SQRT(a'A)) 0.00 cf
INFILTRATION BED CALcutIATION
INFILTRATIONIBED WIDTH= 7.00 R
INFILTRATION ED LENGTH= 19000 ft
INFILTRATION�ED BOTTOM AREA= 1330.00 s1
INFILTRATION ED DEPTH= (entire bottom)
8.00 R
VOID SPACE IN DRAIN ROCK=
PERCOLATION
RATE= 40%
8.00 in/hr Table 3
4LUME IN VOIDS= 4256.00 cf
PERCOLATION VOLUME= 1443 of
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INFILTRATION STORAGE= 5699 of
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I TOTAL DETAINED VOLUME= 5699 cf
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I s 5693 of(required)
THEREFORE STORAGE IS ADEQUATE
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INTERMOUNTAIN ENGINEERING Verraso Village
2587C Southside Blvd.
Melba,Idaho 83641 Meridian,Idaho
(201)941-1245 (FAX)495-2469
-_�_-_ DATE 7113/2015 .
PRE-DEVELOPED FLOW AND VOLUME CALCULATION:Area 2 FILE: VERRASO PAGE
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TIMIE REQUIRED TO DISSIIPATE VOLUME
I TIME CALCULATION ASSUMES A DISCHARGE OFFSITE
I EQUAL TO THE CALCULATED PRE-DEVELOPED FLOW OF 0,00
CFS AND PERCOLATION OVER THE POND BOTTOM AREA
EQUAL TO 2 in./hr.
f
TIME= 6.42 hours
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i GUTTER FLOW CALCULATIONS
POST-DEVELOPED RUNG rF COEFFICIENT(C)= 0.63
LOT TRAVEL TIME= I 30.7 min
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DROP INLETICAPACITIES: VERTICAL CURB= 4.26 cfs(depth at top of curb)
1 ROLLED CURB= 3.15 cfs(depth at top o4 curb)
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. • Sob-l3asih Areas for the diff Irml catch basins are calculated using the design drawings.
Pipe sizing and hydraulic grade caculatlons.
These calculations employ the Manning Equation combined with flow entering the pipe.The
hydraulic grade Is based on itredelermined flow and pipe size.
Lavation III AREA DATA CALCULATIONS
SUB•BASIN SUB-BASIN I CURB GUTTER AVERAGE GUTTER GUTTER TOTAL 25yr 100yr
AREA AREA .I TYPE LENGTH GUTTER TIME CAPACITY TIME 1 Q I 0
'Esic Nft.B) SLOPE min oft Tc lulu cfsinlhr cfs
CB-3 0.23R 59 0.72% 0.5 2.08 31.2 1.17 0.17 157 022
C13-4 0.25,, R 80 0.40.4 0.6' 1.80 31.3 1.17 0.18 1.57 0.25
(8-5 0.25 1 R 61 0.40% 0.8 1.10 31.3 1.17 0.19 1.57 0.25
CB-6 0.25 I R 58 0.40% 0.5' 1.80 31.3 1.17 0.18 1.57 0.25
C B-7 0.15 I R 58 0.67% 0.6 2.03 31.2 1.17 0.11 157 0.15
C B-2 0.51 I R 159 0.50% 1.38 1.89 32.1 1.15 0.37 1.54 0.49
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INTERMOUNTAIN ENGINEERING Verraso Village
2597C Southside Blvd.
Meba,Idaho 83641Meridian,Idaho
(208)941-1245 I(FAX)495-2489 DATE 711312015
SAND AND GREASE TRAP CALCULATIONS Area 2 FILE: VERRASO PAGE
The sand and pease traps Lre sized based on the post-developed flow draining to them.The
throat width is calculated with this flow and a maximum velocity of 0.5 fps through the throat.
SE IMENT(GREASE TRAP SIZING-P.2
NUMBER OF KS - Us*owe(0)1500 sag
DISCHARGE(FS) 1.20
VELOCITY-M IMUM(FPS) 0.50
REQUIRED TH OAT AREA(SF) *DIV/01
TANK SIZE(tot 1,500
TANK WIDTH( 5.25
THROAT-WID (In) #DIV/01
VELOCITY-A UAL(fps) #DIV/01
S DIMENT/GREASE TRAP SIZING
NUMBER OF TANKS 1 Usa one(1)1000 sag
DISCHARGE((IFS) 120
VELOCITY-MAXIMUM(FPS) 0.50
REQUIRED THROAT AREA(SF) 240
TANK SIZE(9a 1,000
TANK WIDTH( ) 4.00
THROAT-W1OT {) 11
VELOCITY-ACL(fps) 0.33
{ PIPE SIZING CALCULATIONS
POST-DEVELOPED RUNOFF COEFFICIENT(C)= 063
LOT TRAVEL TIME= 30.7 min
AVERAGE PIPE FLOW VELOCITY= 1.94 ft/sec
FLOINRATE CALCULATIONa
LccatIon 11 AREA DATA CALCULATIONS
PIPE CONTRIB. CURB GUTTER GUTTER PIPE GUTTER PIPE TOTAL 25yr
i AREA TYPE LENGTH SLOPE LENGTH TIME TIME TIME I Q
ac (V,R) n It It min min Tc Inmr cfs
P-1 1.63 V 159 0.50% 357 0.6 3.1 34.6 1.00 1.03
PIPE SIZING CALCULATIOIII PI
PI IPE DIAMETER• 12 IN
PLLIPE SLOPE 0.0022 N6
MANNMG'S N FOR PIPE. 0.013
�FJ++LOWRATE 1.03 ch
APICITY OF PIPE FLOWING FULL 1.07 PIPE SIZE IS ADEQUATE
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