HomeMy WebLinkAboutSDP 2019-0015; JEFFERSON STREET APARTMENTS; PRELIMINARY HYDROLOGY & HYDRAULICS STUDY; 2020-09-14--... -
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Preliminary
Hydrology & Hydraulics Study
Jefferson Luxury Apartments
at
3039 Jefferson Street
Carlsbad, California
APN: 203-351-22-00
Prepared For
Dr. Bruce Baker
PRIVATE PROPERTIES, LLC
P.O. Box669
Poway, CA 9207 4
Phone: 858-717-2929
Prepared Bv
Landmark Engineering Corporation
Lawrence E. Cole, RCE 36292
3443 Camino Del Rio South #204
San Diego, California 92108
Phone 6 260-0~ ~
~~ RCE36292
Exp. 6/30/'12
Project #2404
September 14, 2020
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INTRODUCTION
PROJECT DESCRIPTION
METHODOLOGY
TABLE OF CONTENTS
Existing Condition Hydrology
Post-Development Hydrology
HYDROLOGY CALCULATIONS
INTENSITY-DURATION DESIGN CHART (100-yr Tc= 5 min.)
INTENSITY-DURATION DESIGN CHART (2-yr Tc= 5 min.)
RAINFALL ISO PLUVIALS
100-YEAR 6-HOUR PRECIPITATION
100-YEAR 24-HOUR PRECIPITATION
2-YEAR 6-HOUR PRECIPITATION
2-YEAR 24-HOUR PRECIPITATION
RUNOFF COEFFICIENTS FOR URBAN AREAS (Table 3-1)
HYDRAULIC CALCULATIONS
CONCLUSION
CERTIFICATION
REFERENCES
ATTACHMENTS
DRAINAGE MAPS
DRAINAGE MAP (EXISTING)
DRAINAGE MAP (PROPOSED)
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INTRODUCTION
The proposed project site is located in the City of Carlsbad, County of San Diego. The project is
located at on the west side of Jefferson Street between Carlsbad Village Drive and Oak A venue. It
is bordered to the east by Jefferson Street, to the east by an unnamed alley, and to the north and
south by existing developed properties. The Assessor's Parcel numbers for the project lot are 203-
351-12-00 and 203-351-13-00. The project proposes grading and improvements for eleven
residential units. This drainage study calculates the peak stormwater discharge entering and
leaving the project site (onsite and offsite drainage) in the existing condition and after
development.
PROJECT SITE DESCRIPTION
The project proposes two commercial/retail floor plan one at 1,100 sf and the other at 1,085 sf. It also
proposes 17 residential units comprised of a total floor area of 18,259 sf with a deck area of 3,624 sf. The
building can be conveniently accessed through an elevator from each of the floors. The off-street parking in
the 1st floor parking garage has direct access from the unnamed alley and located at the rear of the property.
The proposed architectural design maintains a traditional pitch roof and a contemporary look while
utilizing form, material, color changes and clearly defined offsets are utilized to break the building
into smaller vertical units to be consistent with the village character of the community. All the
parking is located on first floor with 19 spaces which includes two handicap spaces. The parking
has direct access to the alley with on-street parking on Jefferson Street.
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METHODOLOGY
Stormwater runoff was calculated using the Rational Method as outlined in the San Diego County
Hydrology Manual, dated June 2003. Stormwater runoff was calculated for an existing and post-
development condition resulting from the 100-year, 6-hour storm event for the project and its
drainage area. Standard intensity-duration curve data was used for the San Diego region supplied
in the Manual.
The soil group used for the site and in the drainage area is soil hydrologic Group B from Map Soil
Hydrology Groups in County Hydrology Manual.
EXISTING CONDITION HYDROLOGY
The existing project site drainage area is approximately 0.436 acres. The site varies in elevation
from a high of 47.95 through the property to a low of 46.44 at the southwest gutter of Jefferson
Street and from a high of 47.95 through the property to a low of 45.17 at the southeast alley swale.
The calculations for, the 0.436 acre drainage area that is graded or disturbed is divided into 5
separate basins (see Drainage Map (See Drainage Map (Existing)) each described as follows:
Area El is a portion of Jefferson Street and an easterly portion of the property on the west side of
Jefferson Street. The stormwater sheet flows to the westerly gutter in Jefferson Street and
then southerly away from the site. The stormwater is concentrated to POC# 1 at a point in
the westerly gutter of Jefferson Street. The runoff flows southerly to the northwesterly
gutter of Oak A venue the surface flow southwesterly along Oak A venue through a series
of cross gutters toward the Pacific Ocean .
Determination of C for existing: Total Area = 2577.58 sf
Impervious = 2029.56 sf
%Imp. = 2029.56/2577.58 = 78.7%
From Table 3-1: C = 0.78
By equation: C = 0.90 x (%imp)+ Cp x (1 -%imp)= 0.7828 use C = 0.78
Area E2 is a westerly portion of the property on the east side of an unnamed alley. The stormwater
sheet flows westerly to the center swale in the unnamed alley and then southerly away
from the site. The stormwater is concentrated to POC#2 at a point in the unnamed alley.
The runoff flows southerly to the northwesterly gutter of Oak A venue the surface flow
southwesterly along Oak A venue through a series of cross gutters toward the Pacific
Ocean.
Determination of C for existing: Total Area = 2577.58 sf
Impervious = 2029.56 sf
%Imp. = 2029.56/2577.58 = 78.7%
From Table 3-1: C = 0. 78
By equation: C = 0.90 x (%imp) + Cp x (1 -%imp) = 0. 7828 use C = 0. 78
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Area E3 is an onsite drainage area that sheet drains southerly over the south boundary into the
adjacent developed property. There is no POC for this area. The runoff sheet flows
westerly into the unnamed alley and for this report the Q is combined at POC#2 for design
purposes only.
Determination of C for existing: Total Area = 2577.58 sf
Impervious = 2029.56 sf
%Imp. = 2029.56/2577.58 = 78.7%
From Table 3-1: C = 0.78
By equation: C = 0.90 x (%imp)+ Cp x (1 -%imp)= 0.7828 use C = 0.78
Area E4 is an onsite drainage area that sheet drains northerly over the north boundary into the
adjacent developed property. There is no POC for this area. The runoff sheet flows
easterly into the Jefferson Street and for this report the Q is combined at POC#l for design
purposes only.
Determination of C for existing: Total Area = 2577.58 sf
Impervious = 2029.56 sf
%Imp. = 2029.56/2577.58 = 78.7%
From Table 3-1: C = 0. 78
By equation: C = 0.90 x (%imp)+ Cp x (1 -%imp)= 0.7828 use C = 0.78
Area E5 is a portion of the unnamed Alley in which the stormwater sheet flows to the centerline of
the Alley then southeasterly to POC#2 at a point in the centerline of the unnamed Alley .
The runoff then flows southerly to the northwesterly gutter of Oak A venue and then it
flows southwesterly in the northwesterly gutter of Oak A venue through Madison Street,
Roosevelt Street, and State Street, about 50' to an existing curb inlet which then carries
the runoff in an underground drainage system which ultimately discharges into the Pacific
Ocean.
Determination of C for existing: Total Area = 2577.58 sf
Impervious = 2029.56 sf
%Imp. = 2029.56/2577.58 = 78.7%
From Table 3-1: C = 0. 78
By equation: C = 0.90 x (%imp)+ Cp x (1 -%imp)= 0.7828 use C = 0.78
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METHODOLOGY (continued)
POST-DEVELOPMENT HYDROLOGY
The project site drainage area is approximately 0.437 acres .
The calculations for, the 0.436 acre drainage area that is graded or disturbed is divided into six (6)
separate basins to define peak flows and DMA determination (see Drainage Map (See Drainage
Map (Proposed)) with each described as follows:
Area Pl is a portion of Jefferson Street and a portion of the parkway on the northeast side of the
property. The stormwater flows southeasterly to POC#l at a point in the westerly gutter of
Jefferson Street. The runoff continues southeasterly to the northwesterly gutter of Oak
A venue and then it flows southwesterly in the northwesterly gutter of Oak A venue
through Madison Street to an existing curb inlet between Madison Street and Roosevelt
Street which then carries the runoff in an underground drainage system and ultimately
discharges into the Pacific Ocean .
Area P2 is a portion of the project on the northeast side of the property consisting of commercial
roof and landscaping which flows to the westerly gutter of Jefferson Street then southerly
away from the site. The stormwater is concentrated to POC#l at a point in the westerly
gutter of Jefferson Street. The runoff flows southerly to the northwesterly gutter of Oak
A venue and then it flows southwesterly in the northwesterly gutter of Oak A venue
through Madison Street to an existing curb inlet between Madison Street and Roosevelt
Street which then carries the runoff in an underground drainage system and ultimately
discharges into the Pacific Ocean.
Area P3 is a portion of the project on the southeast side of the property consisting of commercial
roof and landscaping which flows to the westerly gutter of Jefferson Street then southerly
away from the site. The stormwater is concentrated to POC#l at a point in the westerly
gutter of Jefferson Street. The runoff flows southerly to the northwesterly gutter of Oak
Avenue and then it flows southwesterly in the northwesterly gutter of Oak Avenue
through Madison Street to an existing curb inlet between Madison Street and Roosevelt
Street which then carries the runoff in an underground drainage system and ultimately
discharges into the Pacific Ocean.
Area P4 is a portion of the project on the northwest side of the property consisting of residential
roofs, decks and landscaping which flows to the westerly into the centerline of the
unnamed Alley then southerly away from the site. The stormwater is concentrated to
POC#2 at a point in the centerline of the unnamed Alley. The runoff flows southerly to the
northwesterly gutter of Oak A venue and then it flows southwesterly in the northwesterly
gutter of Oak A venue through Madison Street to an existing curb inlet between Madison
Street and Roosevelt Street which then carries the runoff in an underground drainage
system and ultimately discharges into the Pacific Ocean .
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METHODOLOGY (continued)
POST-DEVELOPMENT HYDROLOGY (continued)
Area PS is a portion of the project on the southwest side of the property consisting ofresidential
roofs, decks and landscaping which flows to the westerly into the centerline of the
unnamed Alley then southerly away from the site. The stormwater is concentrated to
POC#2 at a point in the centerline of the unnamed Alley. The runoff flows southerly to the
northwesterly gutter of Oak A venue and then it flows southwesterly in the northwesterly
gutter of Oak A venue through Madison Street to an existing curb inlet between Madison
Street and Roosevelt Street which then carries the runoff in an underground drainage
system and ultimately discharges into the Pacific Ocean .
Area P6 is an unchanged portion of the unnamed Alley in which the storm water sheet flows to the
centerline of the Alley then southeasterly to POC#2 at a point in the centerline of the
unnamed Alley. The runoff then flows southerly to the northwesterly gutter of Oak
A venue and then it flows southwesterly in the northwesterly gutter of Oak A venue
through Madison Street to an existing curb inlet between Madison Street and Roosevelt
Street which then carries the runoff in an underground drainage system and ultimately
discharges into the Pacific Ocean.
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HYDROLOGY CALCULATIONS
Area< 0.5 square miles. Use Rational Formula
~ =N33 ° 0 9, 38 II
A=Wll7°20' 44"
From Hydrology Manual Soils Map -Soils Group B
Developed Site (Existing) 89.5% impervious
Residential (Proposed) 89.2% impervious
From INTENSITY-DURATION DESIGN CHART
Q100 = CIA
C = 0.83
C = 0.83
Loo= 6.59 in/hr. Tc= 5min
I2 = 2.90 in/hr .
11111 From Existing Drainage Map -...
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Area El:
Area E2:
Area E3:
Area E4:
Area E5:
Area El:
Area E2:
Area E3:
Area E4:
Area E5:
Area El= 0.167 acres
Area E2= 0.235 acres
Area E3 = 0.045 acres
Area E4= 0.016 acres
Area E5 = 0.023 acres
0.486 acres
Q100= CIA= (0.83)(6.59)(0.167) = 0.91 cfs
Q100 =CIA= (0.83)(6.59)(0.235) = 1.29 cfs
Q100 =CIA= (0.83)(6.59)(0.045) = 0.25 cfs
Q100 =CIA= (0.83)(6.59)(0.016) = 0.09 cfs
Q100= CIA= (0.83)(6.59)(0.023) = 0.13 cfs
2.67 cfs
Q2 =CIA= (0.83)(2.90)(0.167) = 0.40 cfs
Q2 =CIA= (0.83)(2.90)(0.235) = 0.57 cfs
Q2 =CIA= (0.83)(2.90)(0.045) = 0.11 cfs
Q2 =CIA= (0.83)(2.90)(0.016) = 0.04 cfs
Q2 = CIA= (0.83)(2.90)(0.023) = 0.06 cfs
1.18 cfs
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HYDROLOGY CALCULATIONS (CONTINUED)
From Proposed Drainage Map
Graded Areas
Area Pl:
Area P2:
Area P3:
Area P4:
Area PS:
Area P6:
Area Pl:
Area P2:
Area P3:
Area P4:
Area PS:
Area P6:
Area Pl= 0.092 acres
Area P2 = 0 .110 acres
Area P3 = 0.114 acres
Area P4 = 0.062 acres
Area PS= 0.061 acres
Area P6 = 0.046 acres
0.485 acres
Q100 =CIA= (0.83)(6.59)(0.092) = 0.50 cfs
Q100 =CIA= (0.83)(6.59)(0.110) = 0.60 cfs
Q100 =CIA= (0.83)(6.59)(0.114) = 0.62 cfs
Q100 =CIA= (0.83)(6.59)(0.062) = 0.34 cfs
Q100 =CIA= (0.83)(6.59)(0.061) = 0.33 cfs
Q100 =CIA= (0.83)(6.59)(0.046) = 0.25 cfs
2.64 cfs
Q2 =CIA= (0.83)(2.90)(0.092) = 0.22 cfs
Q2 =CIA= (0.83)(2.90)(0.110) = 0.26 cfs
Q2 =CIA= (0.83)(2.90)(0.114) = 0.27 cfs
Q2 =CIA= (0.83)(2,90)(0.062) = 0.15 cfs
Q2 =CIA= (0.83)(2.90)(0.061) = 0.15 cfs
Q2 =CIA= (0.83)(2.90)(0.046) = 0.11 cfs
1.16 cfs
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Duration
EQUATION
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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.
Application Form:
(a) Selected frequency _.!..Q!L_ year
p
(b) P6 = ~ in .. P24 = _!.Q_ .~ = _iU_ %(2)
24
(c) Adjusted P6(2l = ---22_ in .
(d) Ix = _5 __ min.
(e) I = ~ in./hr. Calculated by formula
Note: This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
PG 1 1.5 2 2.5 3 3.5 ' 4 4.5 5 5.5 6
Duration I I I I I I I I I I I
5 2.63 3 95 5.27 6.59 7.90 9-22 10.54 , 1 !.86 13. 17 14.49 '15.81
7 2.12 , :u8 4.24 5.30 6.36 7.42; 8.48 9.54 10.60 1 t .66 12.72
10 1.68 2.53 3.37 4.21 5.05 5.901 6.74 7.58 8.42 9.27 10.11
15 t.30 1,95' 2.59 3.24 3.89-4.54'5. 19 . 5.84 6.49 7.13 7.78
20 1,08 1 62 2.15 2.69 3.2'J 3.77: 4.31 _ 4.85 : 5.39 5.93 6.46
25 0,93 1 40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5.13 5.60
30 0.83 1.24 t.66 2.07 2.49 2.90 3.32 3.73 4.15 4.55 4.98
40 0.69 1 03 1.38 1 72 2.07 2.41 2.76 3.10 3.45 3.79 4.13
50 0.60 0 90 1 19 1 49 l 79 2.09 2.39 2.69 2.98 3.28 3.58
60 0.53 0 80 1 06 1.33 1 59 186' 2.12 2.39 2.65 2 92 3.18
90 0.41 0.61 082 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45
120 0.34 0.51 O.SB 0.85 1.02 1.19 1.36 1.53 1.70 1.87 2.04
150 0.29 0.44 0.59 0.73 0.88 1.03 1.18 1.32 1.47 t.62 1,76
180 0.26 0,39' 0.52 0.65 0, 78 0.91 1.04 1.18 1.31 1.44 1,57
240 0.22 . 0.33. 0.43 0.54 0.65 0.76 0.87 0.98 1.08 1.19 1.30
300 0.19 0 28 0.38 0.47 0.56 0.66 0.75 0.85 0.94 1.03 1.13
360 0.17 0.25 0.33 0.42 0.50 0.58 0.67 0.75 0.84 0.92 1.00
FIGURE ~
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0,1 I I I j i I
5 6 7 8 9 10 15 20 30
Minutes
Intensity (in/hr)
6-Hour Precipitation (in)
Duration (min)
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4 5 6
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.
Application Form:
(a) Selected frequency _2 __ year
(c) Adjusted p6(2) = _l_. I_ in .
(d) tx = _5 __ min.
(e) I = ...1.1Q_ in./hr. Calculated by formula
Note: This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
PS 1 .5 2 2.5 3 3.5 4
Duration I I I I I
5 2.63 3.95_s.2z; 6.5917.~19.22: 10.54
7 _?_.12 _ 3.18 __ 4.24_._§.3D_Ji.36. 7.421 8.48
10 1.68 2.53 3.37 4.21 '5.05 . 5.90 6.74 ~ ·1.30 1.9s~2.s(TEJ~_;]s-1 1 s.19
20 1,08 1.62 2.15 . 2.69 .;J.23_3.]7,_4.31
25 0.93 1 40 1.87 2.33. 2.80 3.27 3.73
30 0.83 1.24 1.66' 2.07 2.49 2.90 . 3.32
40 o.69 · .of 1.38 1.?2 2.0-r 2.41 2 76
SQ 0.60 o.9o 1.19 . i.49: 1.19 2.09: 2.39
60 0.53 0 80 1.06 1.33 l 59 1 86 2.12 96 0.41 0.61 0.02· 1.02 1.23 1.43· 1.63
120 0.34 0.51 0.68 -, 0.85: 1.02 1.19 1 36
1SO 0.29 0.44 0.59 0.73 0.88 1.03 1.18
18_~. 0.26 0,39' 0.52, 0.6( 0.7( 0.91 1.04
240 0.22 0.33 0.43 0.54 0.65 0.76 0.87 300 0. 19 028 0,38. 0.47 0.56 0.66 0. 75
360 -0.17 025 0.33. 0.42 0.50 0.58 0.57
4.5 5 5.5 6
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9.54 • 10.60111.66; 12.72
7.58 8.42 9.27 10.1 1
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4.85 5.39 5.93 6.46
4.20 .. 4.67 r 5, 13 · 5.60
3.73 4.15 . 4.55 4.98
3. 10 3.45 + 3.79 4.13
2.69 2.98 ' 3.28 . 3.58
2.39 2.65 . 2.92 . 3.18
1.84 2.04 2.25 2.45
1.53 1.70 . 1.87 2.04
1.32 1.47 1.62 1.76
1.18 1.JI 1.44 1,57
0.98 1.08 1.19 . 1.30
0.85 0.94 ' 1.03 1. 13
0.75 0.84 0.92 1.00
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San Diego County Hydrology Manual
Date: June 2003
Table 3-1
Section:
Page:
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use I Runoff Coefficient "C"
Soil Type
NRCS Elements Count Elements % IMPER. A 8
Undisturbed Natural Terrain (Natural) Permanent Open Space O* 0.20 0.25
Low Density Residential (LDR) Residential. 1.0 DU/A or less 10 0.27 0.32
Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38
Low Density Residential (LOR) Residential, 2.9 DU/A or less 25 0.38 0.41
Medium Density Residential (MOR) Residential. 4.3 DU/A or less 30 0.41 0.45
Medium Density Residential (MOR) Residential, 7.3 DU/A or less 40 0.48 0.51
Medium Density Residential (MOR) Residential, 10.9 DU/A or less 45 0.52 0.54
Medium Density Residential (MOR) Residential. 14.5 DU/A or less 50 0.55 0.58
High Density Residential (HOR) Residential. 24.0 DU/A or less 65 0.66 0.67
High Density Residential (HOR) Residential. 43.0 DU/A or less 80 0.76 0.77
Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77
Commercial/Industrial (G. Com) General Commercial 85~ 0.80 0.80~
Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 9.5 0.83 0.84 0.83
Commercial/Industrial (Limited 1.) Limited Industrial 90 0.83 0.84
Commercial/Industrial _{General 1.) General Industrial 95 0.87 0.87
C
0.30
0.36
0.42
0.45
0.48
0.54
0.57
0.60
0.69
0.78
0.78
0.81
0.84
0.84
0.87
3
6 of 26
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
Cp=0.90x(%imper)+0imper( !-%imper)
Exist Cp=0.90x(.895)+.25(.105)=0.83
Proposed Cp=0.90x(.892)+.25(. 108)=0.83
3-6
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HYDRAULIC CALCULATIONS
Modified 3" x 12" D-25 Curb Outlet@ 2.0%
Area P2 (Q100 = 0.38 cfs)
n = .012
S = 0.02
A=0 .. 25
Wetted perimeter (full) = 1. 5'
R=0.1
Calculated capacity= 1.33 cfs > 0.38 cfs (P2) OK!
Modified 3" x 12" D-25 Curb Outlet@2.0%
Area P3 (Q100 = 0.41 cfs)
n = .012
S = 0.02
A= 0 . .25
Wetted perimeter (full) = 1. 5'
R= 0.1
Calculated capacity= 1.33 cfs > 0.41 cfs (P3) OK!
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CONCLUSION
1. The proposed project does not substantially alter the existing drainage pattern of the site or
area. No flooding will occur due to development.
2. With no reduction in Time of Concentration, the peak Qs post-construction remain
virtually equal to or less than pre-construction. Minor discrepancies of 0.01 cfs are the
result of mathematical round off only. Added Time of Concentration from using planters
will further reduce Intensity (not calculated) will further reduce the post construction
peak flows .
3. As shown above, the proposed project does not create or contribute any runoff water
which would exceed the current capacity of existing storm water drainage systems.
4. The concrete ramp, Area P6, requires a separate sump pump for minimal runoff, Q!Oo=
0.31 cfs. The runoff which is collected in a trench drain and carried to a catch basin on
the upper parking level where it is pumped up to a Biofiltration Basin for Treatment and
Detention .
5. Hydrology Report Summary:
EXPECTED RUNOFF DISCHARGES (a), 5 minutes
Outlet Tributary Area Ql00 Peak Q2 Peak Discharge
(Acres) Discharge ( cfs) (cfs)
Pre Post Pre Post Pre Post
Jefferson Ave POC#l 0.183 0.317 1.00 1.72 0.44 0.75
Unnamed Alley POC#2 0.303 0.169 1.67 0.92 0.74 0.41
Total 0.486 0.486 2.67 2.64 1.18 1.16
Outlets shown are based on changes per development of the project site .
Storm water runoff was calculated using the Rational Method as outlined in the San Diego
County Hydrology Manual, dated June 2003. Stormwater runoff was calculated for an
existing and post-development condition resulting from the 100-year, 6-hour storm event
for the project and its drainage area. Standard intensity-duration curve data was used for the
San Diego region supplied in the Manual.
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CERTIFICATION
Report Preparation
I certify that this document and all attachments were prepared under my direction or supervision in
accordance with a system designed to ensure that qualified personnel properly gathered and
evaluated the information submitted. Based on my inquiry of the person or persons who manage
the system or those persons directly responsible for gathering the information, to the best of my
knowledge and belief, the information submitted is true, accurate, and complete .
CIVIL ENGINEER
September 14, 2020
Date
RCE 36292
Exp. 6/30/22
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REFERENCES
1. County of San Diego Department of Public Works Flood Control Section, San Diego County
Hydrology Manual dated June 2003 .
2. County of San Diego Stormwater Standards Manual .
EX. CDNC.
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EASEMENTS,
AN EASEMENT FOR THE PURPOSE SHOWN BELOW AND RIGHTS
INCIDENTAL THERETO AS SET FORTH IN A DOCUMENT.
GRANTED TO: SAN DIEGO GAS AND ELECTRIC COMPANY
PURPOSE: UNDERGROUNDING FACILITIES AND ABOVE GROUND
STRUCTURES TOGETHER WITH THE RIGHT OF
INGRESS AND EGRESS THEREFROM
RECORDED: NOVEMBER 9, 1976 AS FILE NO. 76-374117 OF
OFFICIAL RECORDS
THE EXACT LOCATION AND EXTENT OF SAID EASEMENT IS NOT
DISCLOSED OF RECORD.
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No. 5097
Exp. 06/30/21
REVISIONS
Description
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ND SCALE
LEGEND•
ITEM
PROPERTY LINE
EX.
EXISTING CONTOUR
EXISTING SPOT ELEVATION
EX. ASPHALT
EX. CONCRETE
EX. WATER METER
EX. FIRE HYCRANT
EX. PO\,/ER POLE
PROPOSED DECK
PROPOSED UPPER DECK
PROPOSED SLOPED ROOF
FLOW DIRECTION
PROPOSED CONCRETE·
PROPOSED CURB
PROPOSED CURB & GUTTER
DRIVE\,/AY
TOP OF CURB
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LOTS 23, 24, 25, 26 IN BLOCK 48 OR TOWN OF CARLSBAD,
IN THE CITY OF CARLSBAD, COUNTY OF SAN DIEGO, STATE OF
CALIFORNIA, ACCORDING TO MAP THEREOF NO. 535, FILED IN
THE OFFICE OF THE COUNTY RECORDER OF SAN DIEGO COUNTY,
MAY 2, 1888.
ASSESSOR"S PARCEL NUMBER:
203-351-22-00
DRAINAGE MAP (PROPOSED) FOR:
JEFFERSON LUXURY APARTMENTS
Carlsbad, CA
PREPARED FOR:
PRIVATE PROPERTIES, LLC
OR. BRUCE BAKER
P.O. BOX 669
POWAY, CA 92074
(858) 717-2929
Sht 1 of 1 Date:9/04/20 Dwn. MC
L
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C
LANDMARK ENGINEERING
CORPORATION
3443 Camino Del Rio South
Suite 204
San Diego, CA 92108
(619) 260-0420
Apr. LEC Dwg. No. 2404-PGP-1
EX, C□NC.
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EASEMENTS:
AN EASEMENT FOR THE PURPOSE SHOWN BELOW AND RIGHTS
INCIDENTAL THERETO AS SET FORTH IN A DOCUMENT.
GRANTED TO: SAN DIEGO DAS AND ELECTRIC COMPANY
I
'
PURPOSE: UNDERGROUNDING FACILITIES AND ABOVE GROUND
STRUCTURES TOGETHER WITH THE RIGHT OF
INGRESS AND EGRESS THEREFROM
RECORDED: NOVEMBER 9, 1976 AS FILE NO. 76-374117 OF
OFFICIAL RECORDS
THE EXACT LOCATION AND EXTENT OF SAID EASEMENT IS NOT
DISCLOSED OF RECORD.
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LEGAL DESCRIPTION:
LDT AREA 13977,8256 SF
IMPERVIOUS AREA 12507.4084 SF
89.5% IMPERVIOUS
LOTS· 23, 24, 25, 26 IN BLOCK 48 OR TOWN OF CARLSBAD,
IN THE CITY OF CARLSBAD, COUNTY OF SAN DIEGO, STATE OF
CALIFORNIA, ACCORDING TO MAP THEREOF NO. 535, FILED IN
THE OFFICE OF THE COUNTY RECORDER OF SAN DIEGO COUNTY,
MAY 2, 1888.
ASSESSOR'S PARCEL NUMBER:
203-351-22-00
DRAINAGE MAP (EXISTING) FOR:
JEFFERSON LUXURY APARTMENTS
Carlsbad, CA
PREPARED FOR: LANDMARK ENGINEERING
CORPORATION
No. Description Approved Date PRIVATE PROPERTIES, LLC
DR. BRUCE BAKER
L
E
C
3443 Camino Del Rio South
Suite 204 P.O. BOX 669
POWAY, CA 92074
(858) 717-2929
Sht 1 of 1 Date:8/05/15 Dwn. MC
San Diego, CA 92108
(619) 260-0420
Apr. LEC Dwg. No. 24D3-TOP0-1