HomeMy WebLinkAboutSDP 14-01; Burke Carlsbad Business Center; Site Development Plan (SDP) (5)Preliminary Hydrology Study
FOR
L0T17
CARLSBAD RACEWAY BUSINESS PARK
PLANNED INDUSTRIAL PERMIT
September 7, 2013
RECEIVED
JAN 0 6 2014
CITY OF CARLSBAD
PLANNING DIVISION
Prepared By:
O'DAY CONSULTANTS
2710 Loker Avenue, Suite 100
Carlsbad, CA 92010
(760) 931-7700
J.N. 12-1001
Timothy 0. Carroll
Exp. 12/31/14
RCE 55381
Table of Contents
Section Description Page No.
A. Introduction and Project Description 3
B. Existing Hydrology Basin Areas And Hydrology Calculations 4
C. Proposed Hydrology Basin Areas And Hydrology Calculations 4
Exhibits
Exhibit A
Exhibit B
Exhibit C
Appendices
Appendix A
Appendix B
Appendix C
Vicinity IVIap
20-Scale Existing Project Conditions Hydrologic IVIap (iVlap Pocket)
20-Scale Proposed Project Conditions Hydrologic Map (Map Pocket)
Hydrologic Calculations - Existing Project Conditions for 100-year
Storm
Hydrologic Calculations - Proposed Project Conditions for 100-year
Storm
County of San Diego Hydrology Manual References
A. Introduction and Proiect Description
Lot 17 of Carlsbad Raceway Business Park project is located north of Lionshead Avenue and east of
Melrose Drive in the City of Carlsbad, California (see Vicinity Map below). The entire site is approximately
4.8 acres. Lot 17 is an existing mass graded lot per approved grading plan Drawing 409-lA. The purpose
of this Preliminary Drainage Study is to support a Planned Industrial Permit "PIP" which proposes the
development of the site for industrial use. The site will include approximately 76,326 s.f. of building
permit area (includes truck docks and trash enclosures) and approximately 177 parking spaces. The
remainder ofthe site will be landscaping.
Under existing conditions, there is a single location where runoff from the lot discharges to as indicated on
City of Carlsbad Grading Plans Drawing No. 409-lA, sheet 14 and Drawing No. 409-1, sheet 23. Runoff
from the site drains to an existing desilting basin that is connected to a 54-inch storm drain that traverses
the site and then discharges into an existing downstream detention basin west of Lot 17. The 54-inch
storm drain is part of the existing drainage infrastructure serving the surrounding Carlsbad Raceway
Business Park. The controlled discharge from the downstream detention basin eventually discharges to
Agua Hedionda Creek. Since the lot is part ofthe mass grading plans for the Carlsbad Raceway Business
Park, a runoff coefficient of 0.9 (Office Professional) is used in the existing hydrology calculations.
Under proposed conditions, the majority ofthe site will drain into separate bioretention basins located
along the southerly property line/right-of-way of Lionshead Avenue and the northeasterly corner ofthe
property. The remaining area in the vicinity ofthe southwest corner ofthe property will be intercepted by
a Urban Green biofiltration catch basin, and two other areas will drain into truck loading docks that are 4.5
feet below the finished floor of the proposed building. All proposed drainage facilities will connect to the
existing drainage infrastructure located on-site. A runoff coefficient of 0.9 (Office Professional) is used in
the proposed hydrology calculations.
B. Hydrologic Calculations
Hydrologic calculations were performed utilizing the San Diego County Rational Method as
described in the San Diego County Hydrology Manual, June 2003. Pertinent references from the
San Diego County Hydrology Manual are enclosed in Appendix "C" as follows:
Table 3-1 Runoff Coefficients for Urban Areas (Rational Method)
Soil Group Map
100-year 6-hour precipitation map
100-year 24-hour precipitation map
Figure 3-1 Intensity Duration Design Chart
In the Rational Method,
Q= Flowrate = CIA, and
C = Runoff coefficient, soil type 'C
1= 7.44P6tc •^*^ Exhibit H
Pe = Precipitation for the 6 hour, 100-year storm, Exhibit 'F'
tc = 5 minutes minimum and calculated using methodology described
in hydrology manual
A = Drainage area in acres, Exhibit 'B'
Existing hydrology basin areas and hydrology calculations are shown on Exhibit"B" and in
Appendix "A". A summary ofthe existing hydrology is shown in the table below.
Table 1. Qioo flow rates for Existing Project Condition
Existing Project Hydrology Results
Basin Area (acres)
Q
(cfs)
A 4.50 29.9
Total* 4.5 29.9
Proposed hydrology basin areas and hydrology calculations are sh own on Exhibit "C" and in
Appendix "B". A summary ofthe proposed hydrology is shown in the table below.
Table 2. Qioo flow rates for Proposed Conditions
Proposed Project Hydrology Results
Basin Area (acres) Q
(cfs)
A 2.06 12.3
B 1.97 10.0
C 0.14 0.9
D 0.12 0.8
Total 4.29 24.0
Comparison of existing hydrology and proposed hydrology is shown in the table below.
Table 3. Qioo flow rates for Existing and Proposed Conditions
Comparison of Existing Hydrology and Proposed Hydrology
Basin Existing Project Hydrology (cfs) Proposed Project Hydrology (cfs)
Total 29.9 24.0
There is an decrease in the storm water runoff from the proposed project conditions compared
to the existing project conditions with a similar runoff coefficient. The decrease can be attributed
to the longer time of concentration associated with the proposed site plan and reduced drainage
area.
Lot 17 - Carlsbad Raceway Business Park Preliminary Hydrology Study
EXHIBITS
CITY OF . OCEAMSIDE
HIGHWAY,
PACIFIC
OCEAN
SITE
BUSINESS PARK DF?.
CITY OF
SAN MARCOS
CITY OF ENCINITAS
VICINITY MAP
NO SCALE
Lot 17 - Carlsbad Raceway Business Park Preliminary Hydrology Study
APPENDIX A
Hydrologic Calculations - Existing Project Conditions for 100-year storm
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 09/04/13
LOT 17 CARLSBAD RACEWAY
131020EF1
EXISTING HYDROLOGY
********* Hydrology Study Control Information **********
Program License Serial Number 6218
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.000
24 hour precipitation(inches) = 5.500
P6/P24 = 54.5%
San Diego hydrology manual 'C values used
Process from Point/Station 100.000 to Point/Station 110.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 404.000(Ft.)
Lowest elevation = 403.000(Ft.)
Elevation difference = 1.000(Ft.) Slope = 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 3.10 minutes
(for slope value of 2.00 %)
Calculated TC of 3.100 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.356(CFS)
Total initial stream area = 0.053(Ac.)
Process from Point/Station 110.000 to Point/Station 120.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 403.000(Ft.)
Downstream point elevation = 389.000(Ft.)
Channel length thru subarea = 490.000(Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 50.000
Slope or 'Z' of right channel bank = 50.000
Estimated mean flow rate at midpoint of channel = 15.305(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 15.305(CFS)
Depth of flow = 0.265(Ft.), Average velocity = 4.353(Ft/s)
Channel flow top width = 26.517(Ft.)
Flow Velocity = 4.35(Ft/s)
Travel time = 1.88 min.
Time of concentration = 4.98 min.
Critical depth = 0.357(Ft.)
Adding area flow to channel
Calculated TC of 4.976 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.8 50
Rainfall intensity = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 3.828
Subarea runoff = 29. 898(CFS) for 4.450(Ac.)
Total runoff = 30.254(CFS) Total area = 4.503(Ac.)
Depth of flow = 0.342(Ft.), Average velocity = 5.162(Ft/s)
Critical depth = 0.469(Ft.)
End of computations, total study area = 4.503 (Ac.)
Lot 17 - Carlsbad Raceway Business Park Preliminary Hydrology Study
APPENDIX B
Hydrologic Calculations - Proposed Project Conditions for 100-year storm
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/30/13
LOT 17 CARLSBAD RACEWAY
131020SF1
PROPOSED HYDROLOGY - BASIN A
********* Hydrology Study Control Information **********
Program License Serial Number 6218
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.000
24 hour precipitation(inches) = 5.500
P6/P24 = 54.5%
San Diego hydrology manual 'C values used
Process from Point/Station 10.000 to Point/Station 20.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 397.800(Ft.)
Lowest elevation = 397.540(Ft.)
Elevation difference = 0.260(Ft.) Slope = 0.520 %
Top of Initial Area Slope adjusted by User to 0.500 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 50.00 (Ft)
for the top area slope value of 0.50 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 4.20 minutes
(for slope value of 0.50 %)
Calculated TC of 4.200 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.457(CFS)
Total initial stream area = 0.068(Ac.)
Process from Point/Station 20.000 to Point/Station 30.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 397.540(Ft.)
Downstream point elevation = 396.320(Ft.)
Channel length thru subarea = 188.000(Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 33.000
Slope or 'Z' of right channel bank = 33.000
Estimated mean flow rate at midpoint of channel = 1.596(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 0.500 (Ft.)
Flow(q) thru subarea = 1.596(CFS)
Depth of flow = 0.175(Ft.), Average velocity = 1.574(Ft/s)
Channel flow top width = 11.569(Ft.)
Flow Velocity = 1.57(Ft/s)
Travel time = 1.99 min.
Time of concentration = 6.19 min.
Critical depth = 0.171(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 6.887(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Rainfall intensity = 6.887(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 0.389
Subarea runoff = 2.224(CFS) for 0.390(Ac.)
Total runoff = 2.681(CFS) Total area = 0.458(Ac.)
Depth of flow = 0.213(Ft.), Average velocity = 1.792(Ft/s)
Critical depth = 0.211(Ft.)
Process from Point/Station 30.000 to Point/Station 30.000
**** SUBAREA FLOW ADDITION ****
Rainfall intensity (I) = 6.887(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Time of concentration = 6.19 min.
Rainfall intensity = 6.887(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 0.517
Subarea runoff = 0.878(CFS) for 0.150(Ac.)
Total runoff = 3.559(CFS) Total area = 0.608(Ac.)
Process from Point/Station 30.100 to Point/Station
**** piPEFLOW TRAVEL TIME (User specified size) ****
60.100
Upstream point/station elevation =
Downstream point/station elevation =
Pipe length = 238.00(Ft.) Slope =
No. of pipes = 1 Required pipe flow
Given pipe size = 18.00(In.)
Calculated individual pipe flow =
Normal flow depth in pipe = 7.05(In.)
Flow top width inside pipe = 17.57(In.)
Critical Depth = 8.64(In.)
Pipe flow velocity = 5.55(Ft/s)
Travel time through pipe = 0.72 min.
Time of concentration (TC) = 6.91 min.
389.700(Ft.)
387.100(Ft.)
0.0109 Manning's N = 0.013
3.559(CFS)
3.559(CFS)
Process from Point/Station 30.100 to Point/Station
**** CONFLUENCE OF MINOR STREAMS ****
60.100
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.608(Ac.)
Runoff from this stream = 3.559(CFS)
Time of concentration = 6.91 min.
Rainfall intensity = 6.418(In/Hr)
Process from Point/Station 40.000 to Point/Station
**** INITIAL AREA EVALUATION ****
50.000
0.000
0.000
0.000
000 1
Decimal fraction soil group A
Decimal fraction soil group B
Decimal fraction soil group C
Decimal fraction soil group D
[COMMERCIAL area type
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance
Highest elevation = 397.800(Ft.)
100.000(Ft,
Lowest elevation = 397.200(Ft.)
Elevation difference = 0.600(Ft.) Slope = 0.600 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 50.00 (Ft)
for the top area slope value of 0.60 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 4.20 minutes
(for slope value of 0.50 %)
Calculated TC of 4.200 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 5.308(CFS)
Total initial stream area = 0.790(Ac.)
Process from Point/Station 50.000 to Point/Station 60.000
**** IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 397.200(Ft.)
Downstream point elevation = 396.240(Ft.)
Channel length thru subarea = 110.000(Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 50.000
Slope or 'Z' of right channel bank = 50.000
Estimated mean flow rate at midpoint of channel = 6.752(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 0.500(Ft.)
Flow(q) thru subarea = 6.752(CFS)
Depth of flow = 0.244(Ft.), Average velocity = 2.274(Ft/s)
Channel flow top width = 24.368(Ft.)
Flow Velocity = 2.27(Ft/s)
Travel time = 0.81 min.
Time of concentration = 5.01 min.
Critical depth = 0.258(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 7.898(In/Hr) for a 100.0 year storm
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Rainfall intensity = 7.898(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 1.037
Subarea runoff = 2.883(CFS) for 0.430(Ac.)
Total runoff = 8.190(CFS) Total area = 1.220(Ac.)
Depth of flow = 0.262(Ft.), Average velocity = 2.387(Ft/s)
Critical depth = 0.277(Ft.)
Process from Point/Station
**** SUBAREA FLOW ADDITION
60.000 to Point/Station 60.000
Rainfall intensity (I) =
Decimal fraction soil group A
Decimal fraction soil group B
7.898(In/Hr) for a 100.0 year storm
0.000
0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Time of concentration = 5.01 min.
Rainfall intensity = 7.898(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 1.232
Subarea runoff = 1.544(CFS) for 0.230(Ac.)
Total runoff = 9.734(CFS) Total area = 1.450(Ac.)
Process from Point/Station 60.000 to Point/Station
**** CONFLUENCE OF MINOR STREAMS ****
60.000
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 1.450(Ac.)
Runoff from this stream = 9.734(CFS)
Time of concentration = 5.01 min.
Rainfall intensity = 7.898(In/Hr)
Summary of stream data:
Stream
No.
Flow rate
(CFS)
TC
(min)
Rainfall Intensity
(In/Hr)
1
2
Qmax(1)
Qmax(2)
559
734
1.000
0.813
000
000
6. 91
5.01
1.000 *
1.000 *
0.725 *
1.000 *
6.418
7.898
3.559) +
9.734) +
3.559) +
9.734) +
11.469
12.314
Total of 2 streams to confluence:
Flow rates before confluence point:
3.559 9.734
Maximum flow rates at confluence using above data:
11.469 12.314
Area of streams before confluence:
0.608 1.450
Results of confluence:
Total flow rate = 12.314(CFS)
Time of concentration = 5.006 min.
Effective stream area after confluence = 2.058(Ac.
Process from Point/Station 60.100 to Point/Station 60.200
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 387.100(Ft.)
Downstream point/station elevation = 376.400(Ft.)
Pipe length = 149.00(Ft.) Slope = 0.0718 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 12.314(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 12.314(CFS)
Normal flow depth in pipe = 8.33(In.)
Flow top width inside pipe = 17.95(In.)
Critical Depth = 15.92(In.)
Pipe flow velocity = 15.40(Ft/s)
Travel time through pipe = 0.16 min.
Time of concentration (TC) = 5.17 min.
End of computations, total study area = 2.058 (Ac.)
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/30/13
LOT 17 CARLSBAD RACEWAY
131020SF2
PROPOSED HYDROLOGY - BASIN B
********* Hydrology Study Control Information **********
Program License Serial Number 6218
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.000
24 hour precipitation(inches) = 5.500
P6/P24 = 54.5%
San Diego hydrology manual 'C values used
Process from Point/Station 90.000 to Point/Station 100.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 395.700(Ft.)
Lowest elevation = 395.500(Ft.)
Elevation difference = 0.200(Ft.) Slope = 0.400 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 50.00 (Ft)
for the top area slope value of 0.40 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 4.20 minutes
(for slope value of 0.50 %)
Calculated TC of 4.200 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.672(CFS)
Total initial stream area = 0.100(Ac.)
Process from Point/Station
**** STREET FLOW TRAVEL TIME
100.000 to Point/Station
SUBAREA FLOW ADDITION ****
110.000
0.0140
0.0330
2.195(CFS)
1.288(Ft/s)
Top of street segment elevation = 395.500(Ft.)
End of street segment elevation = 394.300(Ft.)
Length of street segment = 150.000(Ft.)
Height of curb above gutter flowline = 6.0(In.)
Width of half street (curb to crown) = 30.000(Ft.)
Distance from crown to crossfall grade break = 28.490(Ft.)
Slope from gutter to grade break (v/hz) = 0.033
Slope from grade break to crown (v/hz) = 0.033
Street flow is on [1] side(s) of the street
Distance from curb to property line = 10.000(Ft.)
Slope from curb to property line (v/hz) = 0.020
Gutter width = 1.500(Ft.)
Gutter hike from flowline = 0.125 (In.)
Manning's N in gutter = 0.0140
Manning's N from gutter to grade break =
Manning's N from grade break to crown =
Estimated mean flow rate at midpoint of street =
Depth of flow = 0.299(Ft.), Average velocity =
Streetflow hydraulics at midpoint of street travel
Halfstreet flow width = 10.249(Ft.)
Flow velocity = 1.29(Ft/s)
Travel time = 1.94 min.
Adding area flow to street
Rainfall intensity (I) =
Decimal fraction soil group A
Decimal fraction soil group B
Decimal fraction soil group C
Decimal fraction soil group D
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Rainfall intensity = 6.923(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 0.527
Subarea runoff = 2.977(CFS) for 0.520(Ac.)
Total runoff = 3.648(CFS) Total area =
Street flow at end of street = 3.648(CFS)
Half street flow at end of street = 3.648(CFS)
Depth of flow = 0.371(Ft.), Average velocity = 1
Flow width (from curb towards crown)= 12.414(Ft.)
TC = 6.14 min.
,923(In/Hr) for a
0.000
0.000
0. 000
1. 000
100.0 year storm
0.620(Ac.)
452(Ft/s)
Process from Point/Station 110.000 to Point/Station
**** CONFLUENCE OF MINOR STREAMS ****
110.000
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.620(Ac.)
Runoff from this stream = 3.648(CFS)
Time of concentration = 6.14 min.
Rainfall intensity = 6.923(In/Hr)
Process from Point/Station 120.
**** INITIAL AREA EVALUATION ****
000 to Point/Station 130.000
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 397.800(Ft.)
Lowest elevation = 397.550(Ft.)
Elevation difference = 0.250(Ft.) Slope = 0.500 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 50.00 (Ft)
for the top area slope value of 0.50 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 4.20 minutes
(for slope value of 0.50 %)
Calculated TC of 4.200 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.537(CFS)
Total initial stream area = 0.080(Ac.)
Process from Point/Station 130.000 to Point/Station
**** IMPROVED CHANNEL TRAVEL TIME ****
140.000
Upstream point elevation = 397.550(Ft.)
Downstream point elevation = 393.600(Ft.)
Channel length thru subarea = 430.000(Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 50.000
Slope or 'Z' of right channel bank = 50.000
Estimated mean flow rate at midpoint of channel
Manning's 'N' = 0.015
Maximum depth of channel = 0.500(Ft.)
Flow(q) thru subarea = 4.106(CFS)
Depth of flow = 0.200(Ft.), Average velocity =
Channel flow top width = 20.028(Ft.)
Flow Velocity = 2.05(Ft/s)
Travel time = 3.50 min.
Time of concentration = 7.70 min.
4.106(CFS)
2.047(Ft/s)
100.0 year storm
Critical depth = 0.211(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 5.982(In/Hr) for a
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.8 50
Rainfall intensity = 5.982(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.850 CA = 1.148
Subarea runoff = 6.458(CFS) for 1.270(Ac.)
Total runoff = 6.864 (CFS) Total area = 1.350(Ac.)
Depth of flow = 0.252(Ft.), Average velocity = 2.386(Ft/s)
Critical depth = 0.270(Ft.)
Process from Point/Station 140.000 to Point/Station
**** CONFLUENCE OF MINOR STREAMS ****
140.000
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 1.490(Ac.)
Runoff from this stream = 7.577(CFS)
Time of concentration = 7.70 min.
Rainfall intensity = 5.982(In/Hr)
Summary of stream data:
Stream
No.
Flow rate
(CFS)
TC
(min)
Rainfall Intensity
(In/Hr)
1
2
Qmax(1)
Qmax(2)
3. 648
7 . 577
1.000 *
1.000 *
0.864 *
1.000 *
6.14
7 . 70
1.000 *
0.797 *
1.000 *
1.000 *
6. 923
5. 982
3.648) +
6.864) +
3.648) +
6.864) +
9.120
10.020
Total of 2 streams to confluence:
Flow rates before confluence point:
3.648 8.864
Maximum flow rates at confluence using above data:
9.120 10.020
Area of streams before confluence:
0.620 1.350
Results of confluence:
Total flow rate = 10.020(CFS)
Time of concentration = 7.701 min.
Effective stream area after confluence = 2.97(Ac.
Process from Point/Station 140.000 to Point/Station 180.200
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 387.800(Ft.)
Downstream point/station elevation = 385.000(Ft.)
Pipe length = 66.00(Ft.) Slope = 0.0424 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 10.730(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 10.020 CFS)
Normal flow depth in pipe = 8.95(In.)
Flow top width inside pipe = 18.00(In.)
Critical Depth = 15.09(In.)
Pipe flow velocity = 12.22(Ft/s)
Travel time through pipe = 0.09 min.
Time of concentration (TC) = 7.79 min.
End of computations, total study area = 1.97 (Ac.)
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/30/13
LOT 17 CARLSBAD RACEWAY
131020SF3
PROPOSED HYDROLOGY - BASIN C
********* Hydrology Study Control Information **********
Program License Serial Number 6218
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.000
24 hour precipitation(inches) = 5.500
P6/P24 = 54.5%
San Diego hydrology manual 'C values used
Process from Point/Station 150.000 to Point/Station 160.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 398.000(Ft.)
Lowest elevation = 393.800(Ft.)
Elevation difference = 4.200(Ft.) Slope = 8.400 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 8.40 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 2.20 minutes
(for slope value of 10.00 %)
Calculated TC of 2.200 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.464(CFS)
Total initial stream area = 0.069(Ac.)
Process from Point/Station 160.000 to Point/Station
**** PIPEFLOW TRAVEL TIME (User specified size) ****
160.100
Upstream point/station elevation = 391.900(Ft.)
Downstream point/station elevation = 8.000(Ft.)
Pipe length = 8.00(Ft.) Slope = 47.9875 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.464(CFS)
Given pipe size = 6.00(In.)
Calculated individual pipe flow = 0.4 64(CFS)
Normal flow depth in pipe = 0.46(In.)
Flow top width inside pipe = 3.19(In.)
Critical Depth = 4.17(In.)
Pipe flow velocity = 67.06(Ft/s)
Travel time through pipe = 0.00 min.
Time of concentration (TC) = 2.20 min.
Process from Point/Station 160.100 to Point/Station
**** PIPEFLOW TRAVEL TIME (User specified size) ****
160.200
Upstream point/station elevation =
Downstream point/station elevation =
Pipe length = 237.00(Ft.) Slope =
No. of pipes = 1 Required pipe flow
Given pipe size = 6.00(In.)
Calculated individual pipe flow = 0.464(CFS)
Normal flow depth in pipe = 4.14 (In.)
Flow top width inside pipe = 5.55(In.)
Critical Depth = 4.17(In.)
Pipe flow velocity = 3.21(Ft/s)
Travel time through pipe = 1.23 min.
Time of concentration (TC) = 3.43 min.
391.800(Ft.)
389.400(Ft.)
0.0101 Manning's N = 0.013
0.464(CFS)
Process from Point/Station 160.200 to Point/Station
**** PIPEFLOW TRAVEL TIME (User specified size) ****
180.100
Upstream point/station elevation =
Downstream point/station elevation =
Pipe length = 60.00(Ft.) Slope =
No. of pipes = 1 Required pipe flow
Given pipe size = 6.00(In.)
Calculated individual pipe flow =
389.400(Ft.)
388.800(Ft.)
0.0100 Manning's N = 0.013
0.464(CFS)
0.464(CFS)
Normal flow depth in pipe = 4.16(In.)
Flow top width inside pipe = 5.53(In.)
Critical Depth = 4.17(In.)
Pipe flow velocity = 3.19(Ft/s)
Travel time through pipe = 0.31 min.
Time of concentration (TC) = 3.75 min.
Process from Point/Station 180.100 to Point/Station 180.100
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.069(Ac.)
Runoff from this stream = 0.464(CFS)
Time of concentration = 3.75 min.
Rainfall intensity = 7.904(In/Hr)
Process from Point/Station 170.000 to Point/Station 180.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 397.500(Ft.)
Lowest elevation = 393.800(Ft.)
Elevation difference = 3.700(Ft.) Slope = 7.400 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 90.00 (Ft)
for the top area slope value of 7.40 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 2.60 minutes
(for slope value of 5.00 %)
Calculated TC of 2.600 minutes is less than 5 minutes,
resetting. TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.464(CFS)
Total initial stream area = 0.069(Ac.)
Process from Point/Station 180.000 to Point/Station 180.100
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 392.300(Ft.)
Downstream point/station elevation = 388.800(Ft.)
Pipe length = 73.00(Ft.) Slope = 0.0479 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0 . 464 (CFS)
Given pipe size = 6.00(In.)
Calculated individual pipe flow = 0.464(CFS)
Normal flow depth in pipe = 2.55(In.)
Flow top width inside pipe = 5.93(In.)
Critical Depth = 4.17(In.)
Pipe flow velocity = 5.82(Ft/s)
Travel time through pipe = 0.21 min.
Time of concentration (TC) = 2.81 min.
Process from Point/Station 180.100 to Point/Station 180.100
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.069(Ac.)
Runoff from this stream = 0.464(CFS)
Time of concentration = 2.81 min.
Rainfall intensity = 7.904(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (min) (In/Hr)
0.464 3.75 7.904
0.464 2.81 7.904
1.000 * 1.000 * 0.464) +
1.000 * 1.000 * 0.464) + = 0.927
1.000 * 0.750 * 0.464) +
1.000 * 1.000 * 0.464) + = 0.811
Qmax(1) =
Qmax(2) =
Total of 2 streams to confluence:
Flow rates before confluence point:
0.464 0.464
Maximum flow rates at confluence using above data:
0.927 0.811
Area of streams before confluence:
0.069 0.069
Results of confluence:
Total flow rate = 0.927(CFS)
Time of concentration = 3.746 min.
Effective stream area after confluence = 0.138(Ac.)
Process from Point/Station 180.100 to Point/Station 180.200
**** PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 388.800(Ft.)
Downstream point/station elevation = 385.000(Ft.)
Pipe length = 59.00(Ft.) Slope = 0.0644 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.927(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 0.927(CFS)
Normal flow depth in pipe = 2.59(In.)
Flow top width inside pipe = 9.88(In.)
Critical Depth = 4.85(In.)
Pipe flow velocity = 7.41(Ft/s)
Travel time through pipe = 0.13 min.
Time of concentration (TC) = 3.88 min.
End of computations, total study area = 0.138 (Ac.
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software,(c)1991-2006 Version 7.7
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/30/13
LOT 17 CARLSBAD RACEWAY
131020SF4
PROPOSED HYDROLOGY - BASIN D
********* Hydrology Study Control Information **********
Program License Serial Number 6218
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 3.000
24 hour precipitation(inches) = 5.500
P6/P24 = 54.5%
San Diego hydrology manual 'C values used
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 70.000 to Point/Station 80.000
**** INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type ]
(Office Professional )
Impervious value, Ai = 0.900
Sub-Area C Value = 0.850
Initial subarea total flow distance = 80.000(Ft.)
Highest elevation = 397.300(Ft.)
Lowest elevation = 393.700(Ft.)
Elevation difference = 3.600(Ft.) Slope = 4.500 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 90.00 (Ft)
for the top area slope value of 4.50 %, in a development type of
Office Professional
In Accordance With Table 3-2
Initial Area Time of Concentration = 2.60 minutes
(for slope value of 5.00 %)
Calculated TC of 2.600 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.904(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.850
Subarea runoff = 0.806(CFS)
Total initial stream area = 0.120(Ac.)
End of computations, total study area = 0.120 (Ac.)
Lot 17 - Carlsbad Raceway Business Park Preliminary Hydrology Study
APPENDIX C
County of San Diego Hydrology Manual References
7 8 9 10 20 30 40 50 1
Minutes
Duration
Directions for Application:
(1) Fmm precipitation maps determine 6 hr and 24 hr amounts
forthe selected frequency. These maps are included in the
County Hydrotogy 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 Ihe 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 year
P24 {b)P6 =
(c) Adjusted PQ(2) = in.
(d) tj( = min.
(e) l= in./hr.
Note; This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
P6
Duration
7
10
IS
"20
25
40
50
60
z*?
120
ISO
180 240
300
~360
2.63
}.68
Tso
1.08
0.93
0.83
0.69
060
0.53
0.41
0.34
0.26
019
0.17
3.95; 5.27
3.18^4.24
' 2jS3'a37
j1.62!2Tl5 1l.40't.87
1124'fee
1ro3FT38
0.90! 119
0.80:1.06
"iO.61 i a82
"• 0.51 i 6.68
O^lp.59
70J9T0,52
~0ji3T6r43"
0^810.38
'0.25[0.33
2-5
1
3.5
1
4.S_
I
5.5
I
16.59! 7.90,9.22
[^.SOj 6.36! 7.42'
14^21 is^ossao'
'3:24] 3.89! 4.54 •
"2.69 = 3.23 53.77'
i Z33^2!80l3J27^
^.07""2.49t2.90;
• 1.72 •2.07 •2:41"
1.49 •1.79" 2.09'
1.33 1.59; 1.86:
ljB2ri;23]T43'
0.85' 1.02 J.19^
q^sjasa: 1.03"
0.65^78 rag-T
054^0.65; ares
6.47'6.56^0.66'
0.42'b.50'0.58'
10.54 11.86
8.48 • 9.54 •
6J4j^7.58'
5.19 j 5.84 ^
4.3Tt4JB5j
3.73I 4.20 '
'3.32"r3:73 '
2^76' 3 10 '
2.39I2.69
2.12t 2.39^
1.63 I 1.84 •
1.36 ri^53 •
1J8Tl.32
1.04Tiri8~j
Ojj? • a98J
0.75 "i 0.85 •
0.67 70.75"
1317 14.49 15.81
10.60'11.66 J2.72
8^42 i 9^7"l6.11
'6.49T7.I3 ] 7.78 5:39X5.93TM6"
4.67j'5.13T5.60"
4115 ! 4.56- 4.98
3.45 ' 3>9 • 4; i3
2.98 ; 3.28 ' 3.58
2.65X 2.92 3.18
2.04"'i 2 25-2.45
1.70 i 1.87" 2. W
I.47T1J62J 1 76^
1.31
1.(M
0.94 ! 1.03 ! 1.13
6.84 '0.92 '~1.00
1.44 I 1.57
Tl9 1 liW
FIGURE
Intensity-Duration Design Chart« Template
San Diego County Hydrology Manual
Date: June 2003
Section:
Page:
3
6 of 26
Table 3-1
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use Runoff Coefficient "C"
Soil Type
NRCS Elements County Elements % IMPER. A B C D
Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 0.30 0.35
Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32 0.36 0.41
Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46
Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49
Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52
Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57
Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60
Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63
High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71
High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 0.79
Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 0.78 0.79
Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 0.81 0.82
Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (General L) General Industrial 95 0.87 0.87 0.87 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
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 Ti 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)
Element* DU/
Acre
.5% 1% 2% 3% 5% 10% Element* DU/
Acre LM Ti LM Ti LM Ti LM Ti LM Ti LM Ti
Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9
LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4
LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8
LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6
MDR 4.3 50 10.2 70 9.6 80 8.1 95 7.8 100 6.7 100 5.3
MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8
MDR 10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5
MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 100 4.3
HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5
HDR 43 50 5.3 65 4.7 75 4.0 85 3.8 95 3.4 100 2.7
N. Com 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7
G. Com 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4
O.P./Com 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
Limited I. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
General I. 50 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
3-12
AE
Feet
• 5000
.4000
.3000
• 2000
— 1000
900
aoo
TWO
— 500
Tc = /lt.9Ln'
V AE ^
EQUATION
0.385
Tc = Time of concentration (ho ure)
L = Watercourse Distance (miles)
AE = Change in elevation along
effective slope line (See Figure 3-5) (feet)
Tc
Hours
S
400
• 300
•200
• 100
I—too
90
80
70
\
\
\ Miles Feet
\
. 4000
\
— 3000
50
— 40
•30
.20
10
0.5-
.2000
1800
1600
— 1400
— 1200
• 1000
900
1—800
•700
• 600
-500
• 400
-300
• 200
AE
SOURCE: California Division of Higliways (1941) and Kirplch (1940)
Minutes
• 240
180
120
-60
-50
• 40
1—30
•20
— 18
— 16
~14
12
•10
— 9
8
7
6
— 4
—3
Tc
Nomograph for Determination of
Time of Concentration (Tc) or Travel Time (Tt) for Natural Vyfcitersheds
FIGURE
Watershed Divide,
Watershed
Divide
Stream Profile
Area "A" = Area "B"
SOURCE: Califomia Division of Highways (1941) and Kirplch (1940)
Design Point
(Watershed Outlet)
FIGURE
Computation of Effective Slope for Natural Watersheds
5 6 7 8 9 10
Discharge (C.F.S.)
20 30 40 50
EXAMPLE:
Given: Q = 10 8 = 2.5%
Chart gives; Depth " 0.4, Velocity = 4.4 f.p.s.
SOURCE: San Diego County Department of Special District Services Design Manual
FIGURE
Gutter and Roadway Discharge - Velocity Chart
LU 0.
O _l
w
.0.3
,0.2
0.15
0.10
0.09
0.08
0.07
0.06
^•0.05
0.04
S.0.03
- 0.02
0.01
0.009
0.008
0.007
0.006
0.005
EQUATION: V = 149. s''2
n
•-0.2
.0.3
.0.4
0.5
^0.6
CC
0.00-^^
0.003
0.002
-0.001
0.0009
0.0008
- 0.0007
0,0006
0.0005
0.0004
t 0.0003
0.8
0.9
1.0
\
\
-2
r 5
6
7
8
9
10
50
r40
-30
20
r10
>
•a
9
••8
-7
6
i- 20
GENERAL SOLUTION
SOURCE: USDOT, FHWA, HDS-3 (1961)
1.0
0.9
•0.8
'0.7
0.6
•0.5
-0.01
.0.02
•0.03
c
'O '
£
(U
o
O
w
UJ r0.05
r0.04
0.06
i.0.07
i.0.08
io.09
^0.10
0.2
•0.3
^-0.4
FIGURE
Manning's Equation Nomograph
County of San Diego
Hydrology Manual
Rainfall Isopluvials
100 Year Rainfall Event - 6 Hours
Isopluvial (inches)
DPW
MV 6 ntowED wn>«n wwRAHrr OF MiY KM. Em» e)a>i^ OR avIJB), MCUVMa MiT NOT UUn» TO. M>l^ WMWWriES OF MnCHAMTMUTV AND FITNESS FOR A PMniCULAR PUV03E.
3 0 3 Miles
Coimty of San Diego
Hydrology Manual
Rainfall Isoplmials
100 Year RainfaU Event - 24 Hours
tsopluvial (inches)
Hiiv San Dics) Lltivcrcd?
MAP IS WfT>«X/T W<WRAMTV Of AKf PO—. , ™
OF MBtcHANTAaiJTY AMI FTTNESS FOR APMtncuuR punoat
CoeW SwGIS. M llgM> RMMWML
117°30'0'W 117°15'0'W 117°0'0"W 116°45'0'W 116°30'0'W 116°15'0'W
I I I I ' I I
z -
Orange
County
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I I I I I
117°30'0'W
I I I i I I I I I I I I I
117°15'0'W 117°0'0"W 116°45'0'W
I I I I I
116°30'0'W
r i r i T r i T i i i i i i
CO
L. CO
I I I I I I I I T I I I I
County of San Diego
Hydrology Manual
Soil Hydrologic Group
- z
-
. z
b
. in
Legend
" Major Roads
^ Incorporated City Bdy
HYDROLOGIC SOIL GROUP
Hydrologic Group Undefined
• Hydrologic Group A
- Hydrologic Group B
Hydrologic Group C
•Hydrologic Group D
No Soil Data
Note: Soil Data Source
USDA/NRCS
SSURGO Soils 2007
N
A 31.50 3 Miles
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116°15'0"W