HomeMy WebLinkAboutCDP 2016-0006; MFD-01; PRELIMINARY HYDROLOGY CALCULATIONS; 2017-09-15r· -------l
RECORD COPY '
JX;/l.-'1)8/11 -·
Initial Date L-----------··-----· Victor Rodriguez-Fernandez, PE.
1283 E Main St., Ste 109, El Cajon, CA, 92021
engineervictorrf@aol.com PH: (760) 357-2434
PRELIMINARY
HYDROLOGY CALCULATIONS
for
2637 JEFFERSON ST., CARLSBAD
CDP 2016-0006
Victor Rodriguez-Fernandez, RCE 35373
September 15, 2017
9-19. l}
'
Description
Existing property is a flat 0.25 Acre residential lot draining with about a I% slope
towards the West towards an existing multi-family development that is accepting the
existing flows with an exisitng retaining wall. Existing structures and pool to be
demolished. No offsite drainage flows were observed.
The project proposes 4 Apartment Units structure with permeable pavers
driveway and landscaping. There will be an increase of 742 SF of impermeable surface
( from 4152 SF to 4894 SF).
The drainage proposed will be directed towards the same west property line.
There will be no increase of flows by mitigating the imperviousness surfaces increase by
providing permeable pavers to increase the Time of Concentration of the flows and
decrease the peak flow for the south side and a proposed 3" Landscape pond to provide
sheet flow as before over the north side tributary area.
The expected proposed conditions maximum runoff for the north side of 0.15 CFS
will be less than the existing conditions runoff of 0.25 CFS, for the south side proposed
0.09 CFS will be less than existing of0.23 CFS. For the previous existing pool concrete
areas draining to the back of the property, similar conditions are proposed with similar
0.0 I Acre tributary areas.
In summary, the proposed project proposes to simulate existing conditions and
increase of runoff will not be expected. The portion of ground between the existing
retaining wall and the property line will receive the same or less peak runoff from the site
as before.
CALCULATIONS:
EXISTING CONDITIONS
NORTH AREA
C = 0.55 (Per Table 2 for Single Family)
L=150' S = (58.3-56.8)/150' =I%
Al =0.11 Ac.
1/2
1.8 x (I.I-C) x (L)
Tc -----------------------------(Fig. 3-3)
1/3
s
1/2
J.8 X (J.J-0.55) X (150)
Tc -----------------------------= 12.1 Min > I = 4.2 (Fig. 3-1)
1/3
(I)
Q I 00 = CIA= 0.55 x 4.2 x 0.11 = 0.25 CFS over 25' > 0.0 I CFS/FT Sheet Flow
SOUTH AREA
C = 0.55 (Per Table 2 for Single Family)
L=l 90' S = (58.0-56.8)/190' = 0.6%
A2 = 0.12 Ac.
1/2
1.8 X (1.1-0.55) X (190)
Tc -----------------------------16.2 Min > I= 3.46 (Fig. 3-1)
1/3
(0.6)
Q 100 =CIA= 0.55 x 3.46 x 0.12 = 0.23 CFS
CENTER AREA
A3 = 0.01 Ac Assume 1=7.0 in/hr (highest chart value for P=2.8)
Q 100 =CIA= 0.95 x 7.0 x 0.01 = 0.07 CFS sheet flow
PROPOSED CONDITIONS
Total Tributary Area= 0.25 Ac
C = 0.70 (Per Table 2 for Multi-Units)
NORTH AREA
A3 = 0.07Ac
LO= 20' S = 3%
To= 6.4/(90/20) = 1.4 min. (used value per Table 3-2 for MDR 14.5 DU/Ac)
LI= 110' S = (57.7-57.0)/110 = 0.6%
1/2
1.8 X (0.40) X (J JO)
Tel -----------------------------= 15.7 Min (Fig. 3-3)
1/3
(0.6)
Tc2 = Time to fill 3" Landscape pond
Assuming Tc= 18.4 min. > Intensity= 3.18 in/hr (Fig. 3-1)
Landscape Pond storage Area= (50+30)/2 x 0.3= 12 CF
Q3 =CIA= 0.70 x 3.18 x 0.07 = 0.156 CFS
Tc2 = 12CF I 0.156 CFS= 77 Sec.= 1.3 min
Total Tc= 1.4 + 15.7 + 1.3 = 18.4 min. > Intensity= 3.18 in/hr (Fig. 3-1)
Q 100 =CIA= 0.70 x 3.18 x 0.07 = 0.15 CFS
> 0.15/15' = 0.01 Sheet Flow over proposed Landscape Pond = 0.01 (existing) OK
SOUTH AREA
The initial AO=O.O 14 Ac,
To= 6.4/(90/30) = 2.1 min. (used value per Table 3-2 for MDR 14.5 DU/Ac)
Assuming Tc= 200 min. > Intensity= 0.68 in/hr (Fig. 3-1)
Pavers Storage Area= 3,738 SF x 0.67' x 0.4= I 002 CF
AO+ Al= 0.18 Ac.
QI =CIA= 0.70 x 0.68 x 0.18 = 0.086 CFS
Time to fill Pavers subase
Tl = I 002CF I 0.086 CFS = 11,651 Sec. = 194.2 min
Total Tc = 2.1 + 194.2 = 196.3 min.
I 00 yr maximum peak flow
AO+ Al+ A2 = 0.19 Ac.
Q 100 =CIA= 0.70 x 0.68 x 0.19 = 0.09 CFS
CENTRAL WEST AREA
A3 = 0.01 Ac Assume I=7.0 in/hr (highest chart value for P=2.8)
Q 100 =CIA= 0.95 x 7.0 x 0.01 = 0.07 CFS sheet flow
NORTH
PACIFIC
OCEAN
VICINITY MAP
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GRAPHIC SCALE: 1 "= 1 O'
EXISTING TOTAL TRIBUTARY AREA
11,100 SF= 0.25 ACRES
SHEETS FLOWS TOWARDS THE WEST
~ k. ~
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VICINITY MAP
!
II
LEGEND EXISTING ITEMS
DESCRIPTION
PROPERTY LINE
CENTER LINE
EXISTING SPOT ELEVATION
EXISTING CONTOUR El£VATION
EXISTING CURB & GUTTER
EXISTING BUILDING
EXISTING WOOD FENCE
EXISTING IRON FENCE
EXISTING Cl!AJN LINK FENCE
EXISTING SEWER M>JN LINE
EXISTING OVERHEAD ElIC!RICAL LINE
EXISTING RETAINING WALL
EXISTING TREE
EXISTING PALJ.I
FlNISH SURFACE El£VATION
FlNISH FLOOR El£VATION
FINISH GRADE El£VATION
FLOW LINE El£VATION
TOP OF GRATE ELEVATION
INVERSE ELEVATION
TOP OF WALL
BOTIOM OF WALL
GUTTER
NATURAL GRADE
EXISTING DRAINAGE DIRECTION
EXISTING CONCRETE
EXISTING PAVERS
EXISTING DECK
FOUND MONUMENT AS NOTED
PROJECT ADDRESS
2637 JEFFERSON STREET
SAN DIEGO, CA. 92110
AREA DATA
LOT /REA -11,100 SF
EXISTING IMPERV10US /REA = 4, 152 SF
(EXISTING CONCRETE = 2,450 SF)
(EXISTING BUILDING = 1,702 SF)
SYMBOL
---1(--
X56.75 _,, __
--s
---Oh ---
ASSESSOR PARCEL NUMBER
155-170-25-00
LEGAL DESCRIPTION
THAT PORTION OF LOT 1 (NORTHEAST QUARTER OF THE NORTHEAST
QUARTER), SECTION 1, TOWNSHIP 12 SOUTH. RANGE 5 WEST
SAN BERNANOINO MERIDIAN, IN THE CITY OF CIRLSBAD, COUNTY OF
SAN DIEGO, STATE OF CALIFORNIA, ACCOROING TO omclAL PLAT
THEREOF.
BENCHMARK
DESCRIPTION: PTl139: DEPT OF TRANSPORTATION DISK LOCATION: IN S S/W NEAR THE E ENO OF LAS FLORES DRIVE BRIDGE OVER 1-5
El£VATION: 82.221
FS
FF
FG
Fl
TG
IE
T'II
Bl'/
NG
0
JOSE LUIS IREUANO ANO MARIA ELENA IREUANO
835 LADY BUG LANE,
Prepared By:
VICTOR RODRIGUEZ-FERNANDEZ
1283 E MAIN STREET, SUITE 109
EL CAJON, CA 92021 (760) 357-2434
-----------04/06/2017
v1CTOR RODRIGUEZ-FERNANDEZ DATE
SAN MARCOS, CA. 92069
~ICITY OF CARLSBAD!~
4-UNITS APARMENT COMPLEX
JEFFERSON STREET
OWN BY: VMRP I CHKD BY: VR-F
PROJECT NO.
15-764
BENCH MARK
DESCRIPnON: PI#l1'9· PEPI OE TRANSPORTATION DISK
LOCATION: IN S S/W NEAR THE E END OF US FLORES DBM'. BRIDGE O\JER 1-S
SOURCE CONTROL REQUIREMENT AND SITE DESIGN BMPS:
~ PREVENTION OF IWCIT DISCHARGES INTO THE MS4 ~ PROTECT OUTDOOR MATERIALS STORAGE AREAS FROM RAINFALL. RUN-ON, RUNOFF, AND WIND DISPERSAL
EX. Fl~;~T_T _
:il
LEGAL DESCRIPTION
/HAT PORTION OF LOT 1 (NORIHEAST QUARTER OF /HE NORIHEAST
QUARTER), SECTION 1, TOWNSHIP 12 SOUIH, RANGE 5 WEST
VICINITY MAP
RECORDED:-,,-c-=,,-,------------=-=-=--ELEVATION:~B2-22ul _______ QATUM:~N~G~\1J~2~9 __
NOTES:
1) AJLL DRAINAGE FROM BUILDING FOUNDATION
SHALL BE AT MIN. 2X GRADE 1 O' AWAY
FROM BUILDING FOUNDATION.
iSC3 PROTECT MATERIALS STORED IN OUTDOOR WORK AREAS FROM RAINFALL. RUN-ON, RUNOFF, AND WIND DISPERSAL ~ PROTECT TRASH STORAGE AREAS FROM RAINFALL. RUN-ON, RUNOFF, AND WIND DISPERSAL ~ ADDmoNAL BMPS BASED ON POTENTlAL SOURCES OF RUNOFF POLLUTANTS
ISlE] MAINTAJN NATURAL DRAINAGE PATHWAYS AND HYDROLOGIC FEATURES ~ MINIMIZE IMPERVlOUS AREA ~ MINIMIZE SOIL COMPACTION PERM ANENT BMP'S
----------------------1-----------rr~itMH
SAN BERNAND/NO MERIDIAN, IN /HE CITY OF CARLSBAD, COUNTY OF
SAN DIEGO, STA TE OF CALIFORNIA, ACCORDING TO OFFICIAL PLAT
/HEREOF.
APN: 155-170-25-00
PROJECT ADDRESS
2637 JEFFERSON STREET !
2) AJLL FOUNDATIONS ADJACENT TO PERMEABLE PAVERS
SHALL EXTEND BELOW THE BOTIOM OF THE PAVER
BASE SECTION PER SOIL LETIER DATED 04/10/17
GRAPHIC SCALE
10 5 0 1D 20 ~W~iwwl~u~MJ~~-~~l-iiiiiiiiiil
{ IN FEET )
1 inch -10 ft.
I
I
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I ?;S
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8
~ IMPERVlOUS AREA DISPERSION ISi2il LANDSCAPING WITH NATIVE OR DROUGHT TOLERANT SPECIES
I I
I I
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J I I I
I I
I I __________ J L--------r --
'sLOG coR o/s 'sLOG coR o/s I
~
(D PROPOSED 3• LANDSCAPE POND (50 SF)
@ PROPOSED PERMEABLE PAYERS (3,624 SF)
60.50
ED CC WU<'-. 60.56--. '
ED CC WLK ' ', ' ' _,
', ... "-'", ',·
!PROPOSED CONDITIONS
" ', .,
'
SAN DIEGO, CA. 92110 V,
~
~ V, ~2" c· ..
I ~
i:, " II < ..:,
"' UJ ~~.35 <: 0
AREA DATA
LOT AREA= 11,100 SF
EXISTING IMPERVIOUS AREA = 4, 152 SF
(EXISTING CONCRETE = 2,450 SF)
(EXISTING BUILJllNG = 1,702 SF)
TOTA!. PROPOSED IMPERVIOUS AREA = 4,678 SF
"
"
" I
LE GEN D EXISTING ITEMS
DESCRIPTION DWG.NO.
PROPERTY LINE----------------------------------------
CENTER LINE ----------------------------------------
EXISTING GAS LINE--------------------------------------
EXISTING ~NCE (TYPE AS NOTEO)_ ___________________________ _
EXISTING CONTOUR LINE
EXISTING SEWER LINE------------------------------------
EXISTING WATER UNL-----------------------------------
EXISTING ELECTRIC OVERHEAD LINE ____________________________ _
EXISTING CURB & GUTTER ________________________________ _
EXISTING SIDEWALK _____________________________________ _
EXISTING PAVEMENl ____________________________________ _
EXISTING FLOW DIRECTON ---------------------------------
EXISTING SEWER MANHOLE---------------------------------
FLOWLINE ELEVATION ____________________________________ _
TOP Of CURB ELEVATION _________________________________ _
FINISHED GRACE ELEVATION ________________________________ _
FlNISHED SURFACE ELEVATION..-------------------------------
FlNISHED FLOOR ELEVATION.. _______________________________ _
TOP OF WAll ELEVATION----------------------------------
TOP OF FOOT ELEVATION----------------------------------
NATURA!. GRACE ELEVATION.. _______________________________ _
GUTTER--------------------------------------------
LEGEND PROPOSED ITEMS
DESCRIPTION
PROPOSED FLOW DIRECTION ________________________________ _
PROPDSED CONTOUR LINE----------------------------------
PROPOSED CONCRETE _____________________________ 2,502 SF __
PROPOSED PERMEABLE CONCRETE ________________________ JB SF __
PROPOSED PERMEABLE PAVERS ________________________ J,782 Sf __
PROPOSED BUILDING STRUCTURE ----------------------2,376 Sf __
PROPOSED LANSDCAPE _____________________________ 2,402 Sf __
PROPOSED RET~NIG WAll _________________________________ _
ROPOSED ~~:w
SECTION 8-B
:1
SYMBOL
--GAS --GAS --
--58----_
--s --s
--w --w
--EOH--EOH--
c--~-.. ;:-•; . ' i::J
Ci·i: .·: ·.,·.r,·.::· :: '/::::SJ
QMH
FL
TC
FG
FS
FF
TW
TF
NG
G
SYMBOL
--- --57----_ _:
1-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:1
~1 §l: ~,
I
i I I
NOT SOOI
~ICITY OF CARLSBAD !~
DRAINAGE & BMP PLAN FOR:
MDF-01
VICTOR RODRIGUEZ-FERNANDEZ
1283 E MAIN STREET, SUITE 109
(4-UNJTS APARTMENT COMPLEX) JEFFERSON STREET EL CAJON, CA 92021
(760) 357-2434
DWN BY: VMRP PROJECT NO.
CHKD BY: VR-F CDP 2016-0006 C-2
.•-
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r ~ r~ ~ ~
r ~~
"r
~
.. r
~ .. r~
r~
"~r
!I
40 50
Duration
EQUATION
I = 7.44 Ps o·0.645
I = Intensity (1n/hr)
Ps = 6-Hour Precipitation (in)
D = Duration (min)
' , ...
.... ""r,.. I'
i'o,,,"" " "'"' "'"' , .. " 1 .. ..
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2 3 4
Hours
I I
'
~
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I
I
I
I
I
I
I
p
r
I ~ , .. , ..
I
II UII
5 6
Cr' :I: 0 !:;
-0 ~
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5.5 ~.
5.0 ~
4.55
n
4.0 i
3.5 ~
3.0
2.5
2.0
1.5
1 0
lntenalty-Duratlon Design Chart -Ttmplate
D1rec1lons br ~plication:
( 1) From pre:;lpi1ition maps determine 6 hr and 24 hr amounts
for the sdectd frequency. These maps are included ir. the
County t-vdrcbgy Manual (10, 50, and 100 yr maps included
in lhe Designand Procedure Manual}.
(2) Adjust 6,r p'Bcipitation {if necessary) so that it 1s within
the rangt of 6% to 65% of the 24 hr precipitation {not
applicape toDesert).
(3) Plot 6 hr~rec.pitation on the right side of the chart.
(4) Draw a lhe trough the point parallel to the plotted lines.
(5) This line s th intensity-duration curve for the location
being aralyz!d.
Application Fom:
(a) Se!ectedfreqiency \ ()() year
(b) P6 = 2 ~ in., p24 = ~ .:6 = .:> i %(2>
24
(c) AdjustedP6<~ = _1,~ in.
(d) !,c.= ~ 'lin
(e) I= 4, L Ir/hr.
Note: This nartreplaces the Intensity-Duration-Frequency
curve1 used since 1965.
P6 1 1.!5 2 2.5 3 3.5 4 C.5 S 5.5 6
Duration I I I I I I I I I I I
S 2.63, 3.9!5.27 6.59 7.90 9.22 1054 11.86 13.17 14.49 15 81
7 212-3.-04.24 5.30·6.36 7.42 8.48 . 9.~ 10.60 11.66·12.12
10 tM;,si3.31c.21 's.os s .90'674 1.ss 942 '9.21 ·10.11 ,s 130-f.9s2.s9· 3.24 ;3-99· .. g.· s. ,s s.64 · s cg · 1.13 · 178
:ii> T.oa1-fsf2Ts"' 2:S!f 3.2:f s n · c 31 · 4 es · s.39 • s.93 · s.cs
25 o.93.1.4e1.87· 2.33 ·280-3.27~ 3.73 · 4.:lo · c.s7 · s.13 · s.60
30 0.83:1.2~1.66.2.07~2.49'200: 3.32 : 3,3 4.15 : 4.56 4.98
40 069 1.031.38 1.72 207 241 2.76 3.10 3.45 3.79 4.13
SO 0.60: 0.9411.19. 1.49: 1 79 2.09. 2.39 2.69 2.98 3.28 3.58
60 0.53:0.8(1.06 133 1.59 1.86 2.12 2.39 2.65 2.92 318
90 0.41 ~ 0.6 0.82 1.02. 1 23. 1.43 1 63 1 114 2.04 2 25 2 45
120 0.3450.510.68 0.85.1.02 119: 1.36 . 1.53 . 1.70: 1.87 204
1S0 0.29 0.4J0.59 0 73 0 88 I 03 I 18 I 32 1.47 1 52 1 76
1110 6.:is;o.310.s2·0.65 ·o.1s·o.91' 1.04 · 1.1s · 1.31 · 1.44 1.s1 2 cfa2·0.330.c3·osc·oss·o.1s·oe1 011S ·1 os 119 130
3ClO 0.19J 0.210.38 0.47 .0.56,0.6(0.75 . D.85 0.94 1.03 1.13
0.1 7 ·_Q.2!0.~_0 42 050 0.58 0.67 0?5 0.84 0.92 100
FIG U R
EXISTING 3-1
10 0
90
80
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6 .0
5.0
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20 30
Minutes
I
I
' ~ ,~"" t,~
"
"' I .. "
I"" I "'
~ "'~
•
"" ..
I
40 50
Duration
EQUATION
I = 7.44 Ps o·0.645
I = Intensity (1n/hr)
P5 = 6-Hour Precipitation (in)
D = Duration (min)
~I',
"' r,..I""' I" I' .. r,.. i'r-,. , .. I' I• "'~ .
" r..." I" "' . ~ ~ ~ " , .. " I• "' "" " ~ "r-i"r-~ ... " " " ""~ " I" ... , i" ... " r-,. ... ... "
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111111111111 mm 111111
2 3 4
Hours
~
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4.5 -:,
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3.5 ~
3.0
2.5
2.0
1.5
1.0
Intensity-Duration Design Chart • Template
Directions for Application:
( 1) From precipitation maps determine 6 hr and 24 hr amounts
for the selected frequency. These maps are included in the
County Hydrology Manual (10, 50, and 100 yr maps included
in the Design and Procedure Manual).
(2) Adjust 6 hr precipitation (if necessary) so that it is within
the range of 45% to 65% of the 24 hr precipitation (not
applicaple to Desert) .
(3) Plot 6 hr precipitation on the right side of the chart.
(4) Draw a line through the point parallel to the plotted lines.
(5) This line is the intensity-duration curve for the location
being analyzed .
Appllcatlon Fonn:
(a) Selected frequency \()(:) year
(b) P6 = ~in., P24 = 4 ~ .~: S~ %(21
24 (c) Adjusted p6(2) = 2 ,l'.\ in.
(d) lx,;:200. 0 min 18. 4 min
(e) 1 = 0-. 68 in./hr. 3 .18 i n/Hr
Note: This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
P6 1 1 .5 2 2.5 3 3.S 4 4.5 5 5.5 6
Duration I I I I I I I I I I I
~ 2:63 _3.95(5,2,.7 G.59,7.90 9 .. ,o.54;11.se.13.17>1 4.49 ,1581
7 2.12 . 3.18, 4.24, 5.30, 6.36 .7-~2. 8.48. 9.54 . 10.60111.66. 12 72 ,o 1.611 2.53 3.37 4.21 5.05 5.9() 6.74 7.58 8.42 9.27 10 11
1s 1 ~ -, .9s· 2.59 ~3.24 • J .ss-: 4.S4 · 5 1s • 5.84 .. 6 49 · 1.13 · 1.1a
20 ~oa-,.62~fls2m·i23-:fn' 4 31 • ,.85 · 5.39 • 5.93 · s.46
25 o.~ : 1.40'. 1.a( 2 33) ao-:_ 3.[1 ; 3.73·: 4.20 ~ ,.s7 : 5.13 : 5.60
30 0.83 .._1.24 1.66. 2 .07. 2.49. 2.9(), 3.32 . 3.73 4.15 . 4.56 , 4.98
40 0.69 1.0311.38 1.72 2072.41 2.76 3.10 345 3.79 4.13
so o.60 • o.oo· 1.19 1 49 · 1.19 · 2.os 2.39 · 2.69 2.ae 3.28 · J.58
60 o.53 'o.eo· 1.06 1 33 · 1.59 1.ea • 2.12 · 2.39 · 2.65 · 2.92 · 3. 15
90 ~·", ; o.6,: o.82. 1 .o( 1.23: , .43. , 63 . 1.54 . 2.04 : 2 2s : 2.45
120 0.34 10.51 0.68 0 .85 1.02 1.19 1.36 1.53 1.70 1.87 2.04
150 0.29 . 0.4410.59 0 73. 0.88 1 03 ' 1.18 1.32 . 1 47 ' 1.62 . 1.76
1ao o.26 -0.39io.s2·055·0.1s-o.9;· 1.04 · 11a 1.31 · 1., .. · 1.s1
240 0.22 . 0.33· 0.43 0 54. 065. 0.)6. 0.87 0.98 . 1 08 1.19 . 1.3()
300 o:To 'o.29·0.38 o.,1·0.56·o.e6· o.75 o.ss o.94 1.00 ,.13
360 0.11 • 0.2s · o.33 o 42 • o.so· o.~ • o.67 · o 1s o 84 0.92 1.00
PROPOSED Ip '3.01R El
TA.8LE2
RUNOFF COEFFICIENTS (RATIONAL METHOD)
DEVELOPED AREAS (URBAN)
Land Use Coefficienti C
Soil Type 1)
Residential: Q
Single Family G)
Multi-Units ®
Mobile Homes .65
Rural (lots greater than l /2 acre) .45
Commercial (2)
8096 Impervious .85
Industrial (2)
9096 Impervious .95
NOTES:
(1) Type D soil to be used for all areas.
EXIST TNG
PROPOSED
(2) Where actual conditions deviate significantly from the tabulated
imperviousness values of 8096 or 9096, the values given for coefficient C,
may be revised by multiplylng 8096 or 9096 by the ratio of actual
lmpervlousness to the tabulated impervlousness. Howe,•er1 1n no case shal l
the final coefficient be less than 0 • .50. For example: Consider commercial
property on D soil.
Actual imperviousness = 5096
Tabulated imperviousness = 8096
50 Revised C = 80 x 0.85 0.53
82
Table 3-2
MAXIMUM OVERLAND FLOW LENGTH (LM)
& INITIAL TIME OF CONCENTRATION (T1)
Element* DU/ .RYo 1% 2% 3% RYo 10%
Acre LM Ti 'LM Ti LM Ti LM Ti LM Ti LM Ti
Natural 00 13.2 70 12.R 8R 10.9 100 10.3 100 8.7 100 6.9
LDo 1 ro 12.2 70 11.R 8,R 10.0 100 9.R 100 8.0 100 6.4
LDo 2 ro 11.3 70 10.R SR 9.2' 100 8,8 100 7.4 100 RS
LDo 2.9 m 10.7 70 10.0 8R 8.8 9R 8.1 100 7.0 100 R6
MDo 4.3 00 10.2 70 9.6 80 8.1 9R 7.8 100 6.7 100 R3
MDo 7.3 m 9.2 6R 8.4 80 7.4 9R 7.0 100 6.0 100 4.8
MDo 10.9 00 8.7 6R 7.9 80 6.9 90 6.4 100 R7 100 4.R
MDo 14.R m 8.2 6R 7.4 80 6.R 90 6.0 100 R4 100 4.3
HDo 24 ro 6.7 6R 6.1 7R lll 90 4.9 9R 4.3 100 3.R
HDo 43 RO R3 6R 4;7 7R 4.0 8R 3.8 9R 3.4 100 2.7
N.Com 00 R3 60 4.R 7R 4.0 SR 3.8 9R 3.4 100 2.7
d.Com 00 4.7 60 4.1 7R 3.6 8R 3.4 90 2.9 100 2.4
1 .P./Com 00 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
Limited I. m 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
d eneral I. 00 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100 1.9
*See Table 3-1 for more detailed description
m
E w
:~
1n ·c
l,IJ ~ 8 « ~ !:
1001 •·• I H#YI §
rl.J s z
0 20 S z. -l
~ .u.
toi
i
-------------------------------------------------------------0
EXAMP1.E;.
Given:Wa~~,o)• 7D~
$bpe{s);1.3~
RunoffCoeffident (C) = 0.41
°'8rtand Flow Ttme {T) = 9'.5 Minrrtn
T • 1.8(1.1-C) Vii
'V;'
SOURCE= Airport Drainage. Federal Avialion ~ 19'5
FIGURE
Rational Formula • Overland Time of FloW Nomograph 3.3