HomeMy WebLinkAbout5139; Buildable Pad & Driveway APN 167-080-35; Buildable Pad & Driveway APN 167-080-35; 2006-03-10CIVIL ENGINEERING DESiGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 92081
WWW.CDGENGINEERING.COM
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gj§ (760) 5998901
DRAINAGE STUDY AND HYDROLOGY
REPORT
Buildable Pad & Driveway
APN 167-080-35
Carlsbad, CA
Project No: 05139
Prepared for:
Ms. CHRISTINA WORSCH
655 India Street, San Diego, CA 92101
619-696-6641
Prepared by!
Civil Engineering Design Group
Massood Gaskari, P.E.
NO. C47303
EXP. 12-31-07
Date prepared: 07-28-05
Date Revised 03-10-06
CIVIL ENGINEERING DESIGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA-92081
WWW.CDGENGINEERING.COM
H (760) 599 8585
11 (760) 5998901
I. INTRODUCTION:
This report is for a grading plan, which has been prepared by Civil Engineering
Design Group. The subject property is in the City of Carlsbad, California. The
property contains one residential lot that is currently undeveloped. The grading plan
is for one proposed single family residential structure on this site. The grading plan is
shown on the City Drawing No.GP-433-7A. All off-site streets and the underground
improvements have previously been installed per the City permits. The county of San
Diego Hydrology Manual (version 2003) was used to determine the run -off from
storm having a 100 year return frequency. The results are shown on the attached
calculation sheets.
II. DISCUSSION:
The project consists approximately of 0,5 ± acres. It abuts El Camino Real along its
easterly boundary line, hi the City of Carlsbad. Residential properties are located
immediately adjacent to this property on the westerly sides. Vacant lots are currently
located along the north and the southerly sides of the residence. The site is currently
undeveloped at this time.
Currently, the site can be divided into one basin. The property is relatively steep with
a slope from the west to the east and a low point along the southeasterly corner of the
property. The current topography shows a differential grade elevation of
approximately 55 feet from a high point along the westerly side to a low point on the
southeasterly corner of the property. Runoff from this site flows partially east towards
the El Camino curbside, but mostly south along the roadway easement and the access
road, adjacent to the westerly ROW of El Camino Real. The runoff from the roadway
easement discharges onto a drainage ditch that exists along the southerly side of the
access entry to El Camino. The drainage ditch extends southward along the westerly
side of El Camino. Off-site contribution to this lot is assumed to be from the westerly
property only (please see the attached aerial topography). The area of the off-site
contribution is approximately 0.2 acres that contains one residential property.
The proposed development will maintain the same drainage pattern as the existing.
The proposed development includes a driveway and a residential structure. Most of
the developed flow will be directed towards the southeast. Energy dissipaters and a
gravel basin are proposed for a low point before discharging the runoff onto the
existing access road. Runoff from the access road discharges onto the southerly
drainage ditch. The proposed basin is shown on the attached drainage map.
Flow based BMPs shall be installed per the County requirements and in accordance
with SDRWQCB "California Storm Water. Best Management Practices" handbook -
Industrial/Commercial to be followed in the design of storm run-off systems. The
anticipated increase in flow due to the development of this site for the 100-year storm
is 0.41 C.F.S.
IH. CONCLUSION:
The proposed grading plan and drainage facilities have been designed in accordance
with standard engineering practices and the County of San Diego standard. The
proposed grading plan and drainage facilities will accommodate the run-off generated
on-site for the storm having a 100-year return frequency.
The drainage basin will have ripraps to capture pollutants and debris. The gravel
basin will be created covered with rocks and riprap. The basin will trap targeted
pollutants. These pollutants include trash, sediments, heavy metals, and other
substances. The gravel basin will also provide for gradualrelease of the runoff.
It will be the responsibility of the owner to train employees and / or contract with a
qualified company to maintain the approved BMPS installed on this Project.
Festival Funparks
C JjfLJ^* 0 R N I\A
VICINITY AP
NOT TO SCALE
GRAPHIC SOLE: T • 10'
BEST ORIGINAL
CIVIL ENGINEERING DESIGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 9208]
WWW.CDGENGINEERING.COM
Q (760) 599 8585
II (760) 5998901
..d.
/;
PROJECT NO.
SHEET NO. OF
30
County of San Diego
Hydrology Manual
Soil Hydrologic Groups
Legend
Soil Groups
M Group A
Group B
Group C
Undetermined
| | Data Unavailable
DG! SSiGISc Have Sun Oit^fo (Vivcrccil.; -:|
303 Miles
San Diego County Hydrology Manual
Date: June 2003
Section:
Page:
3
6 of 26
Table 3-1
RUNOFF COEFFICIENTS FOR URBAJV AREAS
Land
NRCS Elements
Undisturbed Natural Terrain (Natural)
Low Density Residential (LDR)
- Low Density Residential (LDR)
Low Density Residential (LDR)
Medium Density Residential (MDR)
Medium Density Residential (MDR)
Medium Density Residential (MDR)
Medium Density Residential (MDR)
High Density Residential (HDR)
High Density Residential (HDR)
Commercial/Industrial (N. Com)
Commercial/Industrial (G. Com)
Commercial/Industrial (O.P. Com)
Commercial/Industrial (Limited I.)
Commercial/Industrial (General I.)
Use
County Elements
Permanent Open Space
Residential, 1.0 DU/A or less
Residential, 2.0 DU/A or less
Residential, 2.9 DU/A or less
Residential, 4.3 DU/A or less
Residential, 7.3 DU/A or less
Residential, 10.9 DU/A or less
Residential, 14.5 DU/A or less
Residential, 24.0 DU/A or less
Residential, 43.0 DU/A or less
Neighborhood Commercial
General Commercial
Office Professional/Commercial
Limited Industrial
General Industrial
Runoff Coefficient "C"
% IMPER.
0'*
10
20
25
30
40
45
50
65
80
80
85
90
90
95
A
0.20
0.27
0.34
0.38
0.41
0.48
0.52
0.55
0.66
0.76
0.76
0.80
0.83
0.83
0.87
Soil Type
B
•0.25 C~
0.32 /«••0.38 (^
0.41
0.45
0.51
0.54
0.58
0.67
0.77
0.77
0.80
0.84
0.84
0.87
C
HOL.)
0.36
/" V ""Ni0.42 _J
i— , *"^
0.45
0.48
0.54
0.57
0.60
0.69
0.78
0.78
0.81
0.84
0.84
0.87
D
0.35
0.41
0.46
0.49
0.52
0.57
0.60
0.63
0.71
0.79
0.79
0.82
0.85
0.85
0.87
*The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff
coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the area
is located in Cleveland National Forest).
DU/A = dwelling units per acre
NRCS = National Resources Conservation Service
3-6
S V" •-• .---.VN •,S VI - i :' , i *• •'. •
County of San Diego
Hydrology Manual
Rainfall Isopluvials
100 Year Rainfall Event - 6 Hours
IsopluvlaJ (Inches)
DPW SaSdS
We Hi^-c San Dic^ Civwd! ';
WnHOOT WAWWTY OF AWT KWO.. WO.UCHMJ, HfT MOT UUTEO TO. THE «JPUtD
TAMJIY A«l FIT>CU FOR * WJCTCUUW
303 Miles
County of San Diego
Hydrology Manual
r\- Kl iX^
Rainfall Isopluvials
100 Year Rainfall Event - 24 Hours
] TM? M~>7 v:
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ensity (in/hr)
Hour Precipitation (in
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s
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Duration
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1
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Note: This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
jP6
Duration
5
7
10
15
20
"" "25
"30
40
50
60
90
120
150
180
240,
300
360
1
i
2:63.__.
1.68
1 30
1.08
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0.69
0.60
0.53_,„.
0.34
0.29
0.26
OJ22
0.19
0.17
1.5
i
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2.53
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0.51
0.44
0.39
0.33
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0.59
0.52
0.43
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2.33
2.07
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0.73
0.65
0.54
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1.79
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3.27
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241
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1.23
1.02
0.88
0.78
0.65
0.56
0.50
1;43
1.19
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0.76
0.66
0.58
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3.73
3.32
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2.39
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0.94
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1.44
1.19
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3-18
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2.04
1.76
1.57
1.30
1.13
1.00
FIGURE
Intensity-Duration Design Ghart - Template
CIVIL ENGINEERING DESIGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 92081
WWW.CDGENGINEERING.COM
H (760) 599 8585
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r= 4,
/"I"":
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%,
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PROJECT NO.
SHEET NO. OF
CIVIL ENGINEERING DESIGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 92081
WWW.CDGENGINEERING.COM
H (760) 599 8585
H (760) 5998901
^?
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/*/*.
4 L:
PROJECT NO.
SHEET NO. OF_
CIVIL ENGINEERING DESIGN GROUP
CIVIL & STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 92081
WWW.CDGENGINEERIMG.COM
U (760) 599 8585
11 (760)5998901
-t M 3 ...... :
PROJECT NO.
SHEET NO. OF
CIVIL ENGINEERING DESIGN GROUP
CIVIL 8, STRUCTURAL ENGINEERS
1057 SYCAMORE AVENUE
VISTA, CA 92081
WWW.CDGENGINEERING.COM
H (760) 599 8585
Oj (760) 5998901
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]/..
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'
$4
±2
PROJECT NO.
SHEET NO. OF
San Diego County Hydrology Manual
Date: June 2003
Section:
Page:
3
12 of 26
Note that the Initial Time of Concentration should be reflective of the general land-use at the
upstream end of a drainage basin. A single lot with an area of two or less acres does not have
a significant effect where the drainage basin area is 20 to 600 acres. ,
Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in
hydrology studies. Initial T; values based on average C values for the Land Use Element are
also included. These values can be used in planning and design applications as described
below. Exceptions may be approved by the "Regulating Agency" when submitted with a
detailed study.
Table 3-2
MAXIMUM OVERLAND FLOW LENGTH (LM)
& INITIAL TIME OF CONCENTRATION (Tj)
Element*
Natural
LDR
LDR
LDR
MDR
MDR
MDR
MDR
HDR
HDR
N. Com
G. Com
O.P./Com
Limited I.
General I.
DU/
Acre
1
2
2.9
4.3
7.3
10.9
14.5
24
43
.5%
LM
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
Ti
13.2
12.2
11.3
10.7
10.2
9.2
8.7
8.2
6.7
5.3
5.3
4.7
4.2
4.2
3.7
1%
LM
70
70
70
70
70
65
65
65
65
65
60
60
60
60
60
Ti
12.5
11.5
10.5
10.0
9.6
8.4
7.9
7.4
6.1
4.7
4.5
4.1
3.7
3.7
3.2
2%
LM
85
85
85
85
80
80
80
80
75
75
75
75
70
70
70
Ti
10.9
10.0
9.2
8.8
8.1
•7.4
6.9
6.5
5.1
4.0
4.0
3.6
3.1
3.1
2.7
3%
LM
100
100
100
95
95
95
90
90
90
85
85
85
80
80
80
Ti
10.3
9.5
8.8
8.1
7.8
7.0
6.4
6.0
4.9
3.8
3.8
3.4
2.9
2.9
2.6
50/c
LM
100
100
100
100
100
100
100
100
95
95
95
90
90
90
90
Ti
8.7
8.0
7.4
7.0
6.7
6.0
5.7
5.4
4.3
3.4
3.4
2.9
2.6
2.6
2.3
10%
LM
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Ti
6.9
6.4
5.8
5.6
5.3
4.8
4.5
4.3
3.5
2.7
2.7
2.4
2.2
2.2
1.9
"See Table 3-1 for more detailed description
3-12
100
UJ
LLl
LUo
Q
01wIT
UJ
I
EXAMPLE:
Given: Watercourse Distance (D) = 70 Feet
Slope (s) = 1.3%
Runoff Coefficient (C) = 0.41
Overland Flow Time (T) = 9.5 Minutes
SOURCE: Airport Drainage, Federal Aviation Administration, 1965
T = 1.8 (1.1-c) V5"
FIGURE
Rational Formula - Overland Time of Flow Nomograph
EQUATION
A E T /11.9L3\0.385
Feet Tc V AE /
5000 Tc = Time of concentration (hours)
- L =« Watercourse Distance (miles)
— 4000 ^E _ change in elevation along
effective slope line (See Rgure 3-5) (feet)
3000 TC
Hours
2000 4
3 jjn-u-r.x
1000
- 900
^ 800 2
-TOO
-60<j\
500 \\
400 N •
— va -*V5^ '
3 OP \^
\
N
200 \
- \\ L
\ Miles Feet
\
\— 100 . 1^n
A
** ^~
0.5 —— 50
, — 40
— 30
— 20
— 10
5
JL-4000
- \
— 3000\\\* — 2000 \
— 1800 \
— 1600 \
— 1400 \
— 1200
1000
— 900
— 800
— 700
— 600
— 500
— 400
"•*
— 300
-
— 200
Minutes
— 240
-ton"— | Qy
' 120
— 100
1-90
— 80
-,70
60
50
— 40
— 30
20
— 18
— 16
— 14
— 12
10
— 9
— 8
— 7
— 6
5
— 4
— 3
AE L Tc
SOURCE: California Division of Highways (1941 ) and Kirpich (1940) ,
FIGURE
Nomograph for Determination of
Time of Concentration (To) or Travel Time (Tt) for Natural Watersheds
0.4
2 3 4 56789 10
Discharge (C.F.S.)
EXAMPLE:
Given: Q = 10 S = 2.5%
Chart gives: Depth = 0.4, Velocity = 4.4 f.p.s.
SOURCE: San Diego County Department of Special District Services Design Manual
20 30 40 50
Gutter and Roadway Discharge - Velocity Chart
FIGURE
3-6
EQUATION: V = 1.49 R*s s1'*n
i
0
L-<1)ex
"5£
c
LJJ
CL
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w
c-0.3
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. 0.03
-
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1 .
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- 0.008 Q
- 0.007 Ij
— -l- 0.006 ^
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- 0.0009
- 0.0008
-0.0007
- 0.0006
- 0.0005
- 0.0004
. 0.0003
£.0.2
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-0.06
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•0.09 t
-0.10
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.
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-
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GENERAL SOLUTION
SOURCE: USDOT, FHWA, HDS-3 (1961)
FIGURE
Manning's Equation Nomograph ^ p»
O" /
0
a:
r 10000
-7000
-6000
-6000
-4000
r3000
- 2000 ;>
-1000
-900
-800 £
- 700 j
- 600 §
-500 |
-400 /*
-300
— 200
100
-90
-80
70
60
50
40
30
20
10
'ijP^fef^^P' v
n ir.HQUIMNIlI OOCfriCICHT tN HA
, .,%',.. • .-. . .
PMC mO, KOUATIOH (14) „,--'''
EXAMPLE (see CASHED LINKS)
IIVIN 1 t,»-'6.0J
I. t4l COi/n • ifoo |.n • .01 J ' LL.
^^_^ d • o.ti O
FJI<b"i~~0~«^I.O CFS
O
UliriSTRUCTiONa ^
o:
NNIIK
H
- 100 ^~
III \
-JO |_L
-to
; 7
; 1
;.7 ^~.
-.8 CO
- .3
E-' -J
-.08 2
-•os 2
-.Ot ^
X
|i T "I
WITH 1 • -^•
OISCHANIE Ox IN ^ s ' ^\^iirf1f''trart1
HAVIN* WIDTH Xt *"" " ^
-
3^-^ U.
0
LU
Q.
w"*" _J
i r-<'
| I JJ-ac"'
1 I ^^*r'^*i-1 \f^"^ (
DKfTH d t OITAIM 0^ FDH
•
CHART 2 9
p. 10
-.08
-.07
-.06
-.05
i
-.04
1-'u_
-.03
-.01 O:
CL
-.008
-.007 w
-.006 ^
Q
.004 cc
O
.003 CD
CC
Z)
O.002
H
X
1-
0.
UJ
.001 Q
-2.0
- 1.0
-.80
-.70
-.60
-.50
r.40
L.30
'-.20
-.10
.08
.07
.06
.05
•04
.03
.02
.01
NOMOGRAPH FOR FLOW
IN TRIANGULAR CHANNELS
37