HomeMy WebLinkAboutSDP 09-04A; PLAZA CAMINO REAL SHOPPING CENTER; DRAINAGE REPORT FOR WESTFIELD CARLSBAD PHASE 2; 2014-08-25RE'VED
DRAINAGE REPORT SEP 022014
CITY OF CARLSBAD
FOR PLANNING DIVISION
WESTFIELD CARLSBAD PHASE 2
SDP 09-04 (A), Drawing XXX-XX
August 25, 2014
Wayne W. Chang, MS, PE 46548
ChININMEMM
Civil Engineejing • Hydrology • Hydraulics • Sedimentation
P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692-0760
FOR REVIEW ONLY
TABLE OF CONTENTS
Introduction........................................................................................................................................ 1
HydrologicAnalysis..........................................................................................................................3
HydraulicAnalyses............................................................................................................................4
Conclusion.........................................................................................................................................4
FlowMaster Results
APPENDICES
100-Year Rational Method Analyses and Supporting Data
100-Year WSGPW Analyses
MAP POCKET
Plan Sheets showing Proposed Storm Drains Serving Open Air Corridor and WSPGW Data
Proposed Condition Rational Method Work Map
FOR REVIEW ONLY
INTRODUCTION
The Westfield Carlsbad Phase 2 project proposes modifications to the Westfield Plaza Camino
Real shopping mall in Carlsbad, California (see Vicinity Map). Phase 1 has been approved and
includes renovation of the easterly portion of the mall. Under Phase 1, the existing anchor
building (formerly the Robinsons-May department store) at the east end of the mall will be
significantly rebuilt and occupied by new tenants. Portions of the surrounding parking lots will
be reconfigured. The perimeter areas of the parking lots will generally have new replacement
paving with some regrading while the central area of the parking lots will be retained and
blended into the perimeter improvements. The existing pavement at the mall entrances from the
public streets will remain, but will be repaired, as needed, and overlayed/resealed. New
landscape islands will be incorporated into the parking lot and porous concrete will be used in
some of the perimeter parking stalls.
CITY OF OCEANSIDE
HIGHWAY 1...Z8
NOT TC
SCALE
CITY OF VISTA
CITY OF
SAN MARCOS
LM'1JI
CITY OF ENCINITAS
Under Phase 2 covered by this report, the indoor mall between the easterly and westerly anchor
stores will be transformed to an open air shopping corridor. This will be accomplished by
removing a large portion of the central roof area between the anchor stores. Phase 2 will also
expand the existing roofs and buildings along some of the perimeter mall areas. Finally, Phase 2
will reconstruct some of the landscape islands and parking lot along the southerly parking area.
The landscape island and parking lot modifications are primarily being done to accommodate
proposed vegetated bio-swales along Marron Road, which are the project's treatment control
BMPs.
Under pre-project conditions, the site is mostly impervious and supports the existing indoor
shopping mall and surrounding parking lots. There are landscaping islands and landscaping areas
spread throughout the exterior areas and parking lots. There is no significant off-site run-on to
the project area. Storm runoff generally flows away from the indoor mall and towards the outer
perimeter of the parking lots. Existing storm drain systems collect the on-site runoff and convey
it northerly to Buena Vista Creek, which is adjacent to the northerly edge of the mall. There are
several discharge points into the creek for the Phase 2 project area flows.
Under post-project conditions, the on-site runoff directions will generally be maintained with the
following three exceptions. First, direct precipitation into the proposed open air mall area will be
captured by new storm drain systems within this area. The generaly storm drain layout has been
established, but the details still need to be finalized. For now, the easterly portion of the open
mall area is proposed to be conveyed easterly within the open air mall, the central portion will
be conveyed north, and the westerly portion will be conveyed westerly within the mall. These
three storm drain systems will ultimately connect to existing drainage systems within the
northerly parking areas. The open air area will reduce the existing roof runoff although the
proposed condition percent impervious is assumed to be similar to existing conditions.
Second, some of the existing buildings and roof areas will be expanded along the mall perimeter.
The new roof areas will be designed to convey runoff to the surrounding parking lot. The
building/roof expansion areas will be within the footprint of areas that currently are mostly
impervious, so the expansion will not significantly alter the flow rates. In areas where the roofs
are changing, but the improvement results in less runoff than existing conditions (i.e., the
drainage areas is being reduced), hydrologic analyses have not been performed.
Third, the reconstructed landscape islands and parking areas will essentially maintain the same
flow patterns as existing conditions. This portion of the project will slightly increase the pervious
area to accommodate vegetated bioswales along Matron Road. Therefore, this parking lot work
will not adversely impact the storm runoff.
The Phase 2 project generally maintains the existing flow patterns, so the existing drainage
infrastructure will serve much of the project runoff. The only new drainage infrastructure will be
the storm drain systems needed to serve the open air corridor. Although the existing drainage
patterns will be altered within the corridor, the storm runoff will still be conveyed to Buena Vista
Creek at existing discharge locations.
This report contains drainage analyses for Hofman Planning & Engineering's Phase 2 final
engineering plans. The project's grading and drainage design were developed entirely by
Hofman Planning & Engineering. This report merely provides drainage analyses for their design.
The analyses in this report only cover the area within the proposed open air corridor and the
project areas tributary to the Phase 2 bioswales.
This report does not analyze the Phase 2 expansion areas that are within the Phase I study area or
that are not tributary to a proposed bioswale. These Phase 2 areas essentially maintain the same
flow patterns and impervious areas as analyzed in the Phase I report or as currently exist, so
there is not a need to analyze these areas.
HYDROLOGIC ANALYSIS
A hydrologic analysis was performed to determine the 100-year flow rates under post-project
(proposed) conditions. As mentioned above, the project generally maintains the same drainage
patterns as pre-project conditions. In addition, the amount of pervious area is being slightly
increased due to the open air corridor and the bioswales. As a result, the existing condition runoff
will generally be the same as the post-project runoff. The County of San Diego's 2003
Hydrology Manual rational method procedure was used for the 100-year hydrologic analyses.
The rational method input parameters are summarized below and the supporting data is included
in Appendix A:
Precipitation: The 100-year, 6- and 24-hour precipitation values are 2.7 and 5.0 inches,
respectively.
Drainage areas: The drainage basins were delineated from the base topography and the
grading plans by Hofman Planning & Engineering. Drainage patterns on the existing roofs
were estimated from a review of aerial photographs. See the Rational Method Work Map in
the map pocket for the basin boundaries, rational method node numbers, and basin areas.
Hydrologic soil groups: The hydrologic soil groups were determined from the Natural
Resources Conservation Service's (NRCS) Web Soil Survey. The soil groups in the study
area include type A, C, and D.
Runoff coefficients: The site is currently fully developed and will remain fully developed.
Land uses throughout the study area were mostly based on the commercial/industrial
(general industrial) category to reflect a 95 percent imperious cover condition. For this land
use category, the runoff coefficient is 0.87 for both type A, C, and D soil. Therefore, the soil
type was entered as "C" in the subbasins for simplicity. The drainage area between rational
method nodes 40 and 41 contains mostly pervious area due to a proposed bioswale.
Therefore, the land use in this area was based on the low-density category to reflect a 20
percent impervious cover.
Flow lengths and elevations: The flow lengths and elevations were obtained from the base
topography and engineering plans.
Rational
Method Node
Number
Proposed
Condition Area,
ac
Proposed Condition
100-Year Flow Rate,
cfs
3 0.93 4.9
12 0.44 2.3
17 0.90 4.8
22 1.73 . 7.6
28 3.41 9.0
31 0.80 5.0
36 1 0.39 2.1
41 1 0.10 0.1
Table 1. Summary of 100-Year Rational Method Results
The proposed condition rational method results are included in Appendix A and summarized in
Table 1. The results are given for the eight major drainage basins in the study area. Each of the
major basins is tributary to separate catch basins or storm drains.
HYDRAULIC ANALYSES
The majority of the major drainage basins analyzed in this report will flow towards existing
catch basins along the southerly end of the parking lot. The runoff to the catch basins will
generally be maintained or marginally reduced. Therefore, the existing catch basins will remain
as is.
The 100-year runoff and drainage facilities in the open air mall area will include three separate
underground storm drain systems that capture and convey runoff to existing underground
systems in the parking lot at the north. Initial results indicate that the proposed condition 100-
year runoff from this area be greater than the capacity of the existing storm drain systems
immediately adjacent to the northerly side of the retail stores. Therefore, the proposed systems
must tie-into the existing systems further north in the parking lot. The downstream hydraulic
grade line is lower further to the north, which benefits the system capacity. The plan sheets in the
map pocket show the proposed storm drain systems (west, central, and east) connecting the open
air corridor to the existing storm drain system. The proposed systems were analyzed using
WSPGW analyses in Appendix B (see the plan sheets in the map pocket for WSPGW
stationing). The downstream end of the analyses were based on a HGL at the ground surface to
represent worst case conditions. Once the HGL reaches the ground, it will not rise much above
the ground level because the flow will spread over the ground surface. The results show that the
proposed storm drains can convey the 100-year runoff with the HGL below the ground surface.
The west, central, and east systems will only serve the open space corridor. The WSPGW
analyses will be refined once the precise grading design of the open space corridor is completed,
but the analyses in Appendix B show that it is possible to convey the corridor runoff to the
existing storm drain system wihout inundating the open space corridor.
The project flow along the southerly parking lot and Marron Road will occur over proposed bio
swales. The proposed swales will have a 1 percent longitudinal slope, 6-foot bottom width, 8-
inch depth, and 3:1 side slopes. A normal depth analysis was performed to assess these swales.
The maximum flow rate from Table I is 9 cfs. A FlowMaster analysis is included after this text
and shows that the normal depth under 9 cfs is 0.46 feet (5.5 inches). Therefore, this swale is
sufficient.
CONCLUSION
Hydrologic and hydraulic analyses have been performed in this report for the Westfield Carlsbad
Phase 2 project by Hofman Planning & Engineering. The analyses were based on their grading
and improvement design. This project will not cause an appreciable change to the existing
condition flow rates. Hofman Planning & Engineering shall use these results to finalize the
4
drainage facility sizing. Additional analyses will be required in the future once the drainage
system in the proposed open air corridor is finalized.
Worksheet for Bioswale
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.030
Channel Slope 0.01000 ftift
Left Side Slope 3.00 ftjft (NV)
Right Side Slope 3.00 ftift (NV)
Bottom Width 6.00 ft
Discharge 9.00 ft'/s
[Results
Normal Depth 0.46 ft
Flow Area 3.44 ft2
Wetted Perimeter 8.94 ft
Hydraulic Radius 0.38 ft
Top Width 8.79 ft
Critical Depth 0.39 ft
Critical Slope 0.01933 ft/ft
Velocity 2.62 ft/s
Velocity Head 0.11 ft
Specific Energy 0.57 ft
Froude Number 0.74
Flow Type Subcritical
[GVF Input Data I
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
[GVF Output Data I
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0.46 ft
Critical Depth 0.39 ft
Channel Slope 0.01000 ftift
Bentley Systems, Inc. Haestad Methods S aster V81 (SELECTseries 1) (08.11.01.03]
51112014 9:16:11 PM 27 Slemons Company Drive Suite 200W Watertown, CT 06796 USA +1.203-755-1666 Page 1 of 2
APPENDIX A
100-YEAR RATIONAL METHOD ANALYSES
AND SUPPORTING DATA
Soil Map—San Diego County Area, California
Map Unit Legend
San Diego County Area, California (CA638)
Map Unit Symbol Map Unit Name Acres In AOl Percent of AOl
CbE Carlsbad gravelly loamy sand, 12.7 8.5%
15 to 30 percent slopes
DaE2 Diablo day, 15 to 30 percent 14.9 10.0%
slopes, eroded
LeE2 Las Flores loamy fine sand, 15 0.1 0.1%
to 30 percent slopes, er oded
LfC Las Flores-Urban land complex, 3.9 2.6%
2 to 9 percent slopes
LvF3 Loamy alluvial land-Huertiuero 2.3 1.6%
complex, 9 to 50 percent
slopes, severely eroded
MIC Marine loamy coarse sand, 2 to 7.4 4.9%
9 percent slopes
MIE Manna loamy coarse sand, 9 to 11.0 7.4%
30 percent slopes
SbC Salinas day loam, 2 t09 percent 43.8 29.3%
slopes
Tf Tidal flats 53.4 35.8%
Totals for Area of Interest 149.5 100.0%
USDA Natural Resources Web Soil Survey 5/112014
Conservation Service National Cooperative Soil Survey Page 3 of 3
100 30
Cl)
I- w I-
Ui Ui z
- 20
z Ui - 0
F
U) 0 -J
U) U.
10
C.) Ui
EXAMPLE:
Given: Watercourse Distance (D) = 70 Feet
Slope (s) =1.3% 1.8 (1 .1-C) V5
Runoff Coefficient (C) = 0.41 T =
3\fl Overland Flow Time (T) = 9.5 Minutes
SOURCE: Airport Drainage, Federal Aviation Administration, 1965
FIGURE
Rational Formula - Overland Time of Flow Nomograph
3m3
ir
0 OAF
M
pll!,O~, Ui
FAI'ap,94,
FAMP-A'.4
w
z No
F't, 4040 -ArM40-
.40 a 9 W Y--OEN a 0
0-.0imo
U.1
0
San Diego County Hydrology Manual
Date: June 2003
Section: 3
Page: 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 T1 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)
& ll1TIAL TIME OF CONCENTRATION (T1)
Element* DU/
Acre
.5% 1% 2% 3% 5% 10%
LM T1 LM T1 Lq T1 LM T, LM T1 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 12 50 1 11.31 70 10.5 1 85 9.21 100 8.81 100 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 1 7.0 100 1 6.0 100 1 4.8
MDR 10.9 50 1 8.7 65 1 7.9 1 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 1 90 4.9 95 4.3 100 3.5
HDR 43 50 5.3 65 4.7 75 4.01 85 3.8 95 3.41 100 2.7
N. Corn 50 5.3 601 4.5 75 4.0 85 3.8 95 3.4 100 2.7
G. Corn 1 50 1 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 1 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 1 3.1 1 80 2.9 90 2.6 100 2.2
General I. 50 3.7 1 60 3.2 1 70 1 2.71 80 2.6 1 90 2.3 1 100 1.9
*See Table 3-1 for more detailed description
3-12
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c)1991-2009 Version 7.8
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 06/27/14 ------------------------------------------------------------------------
Westfield Carlsbad Phase 2
Proposed Conditions
100-Year Storm Event
Hydrology Study Control Information **********
Program License Serial Number 4028
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.700
24 hour precipitation(inches) = 5.000
P6/P24 = 54.0%
San Diego hydrology manual 'C' values used
Process from Point/Station 1.000 to Point/Station 2.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 180.000(Ft.)
Highest elevation = 28.800(Ft.)
Lowest elevation = 27.000(Ft.)
Elevation difference = 1.800(Ft.) Slope = 1.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.21 minutes
TC = [1.8*(1.1_C)*distance(Ft.)".5)/(% slope(1/3))
TC = [1.8*(1.1_0.8700)*( 60.000".5)/( 1.000A(1/3)1= 3.21
The initial area total distance of 180.00 (Ft.) entered leaves a
remaining distance of 120.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.83 minutes
for a distance of 120.00 (Ft.) and a slope of 1.00 %
with an elevation difference of 1.20(Ft.) from the end of the top area
Tt = [11.9*length(Mi)'3)/(elevation change(Ft.))]A.385 *60(minlhr)
= 1.835 Minutes
Tt=[(11.9*0.02273)/( 1.20)]A.385= 1.83
Total initial area Ti = 3.21 minutes from Figure 3-3 formula plus
1.83 minutes from the Figure 3-4 formula = 5.04 minutes
Rainfall intensity (I) = 7.076(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.293(CFS)
Total initial stream area = 0.210 (Ac.)
++++++++++++++++++++++++++-4-+++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 2.000 to Point/Station 3.000
PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 24.760(Ft.)
Downstream point/station elevation = 22.410(Ft.)
Pipe length = 294.00(Ft.) Slope = 0.0080 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.293(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 1.293(CFS)
Normal flow depth in pipe = 6.52(In.)
Flow top width inside pipe = 8.05(In.)
Critical Depth = 6.28 (In.)
Pipe flow velocity = 3.77(Ft/s)
Travel time through pipe = 1.30 mm.
Time of concentration (TC) = 6.34 mm.
Process from Point/Station 2.000 to Point/Station 3.000
SUBAREA FLOW ADDITION
Rainfall intensity (I) = 6.104(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 = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Al = 0.950
Sub-Area C Value = 0.870
Time of concentration = 6.34 mm.
2
Rainfall intensity = 6.104(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.870 CA = 0.809
Subarea runoff = 3.646(CFS) for 0.720(Ac.)
Total runoff = 4.938(CFS) Total area = 0.930(Ac.)
Process from Point/Station 10.000 to Point/Station 11.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 138.000(Ft.)
Highest elevation = 27.400(Ft.)
Lowest elevation = 26.000(Ft.)
Elevation difference = 1.400(Ft.) Slope = 1.014 %
Top of Initial Area Slope adjusted by User to 1.064 %
Bottom of Initial Area Slope adjusted by User to 1.064 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.06 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.14 minutes
TC = [1.8*(1.1_C)*distance(Ft.)".5)/(% slope(1/3)]
TC= [1.8*(1.1_0.8700)*( 60.000".5)/( 1.064"(1/3)]= 3.14
The initial area total distance of 138.00 (Ft.) entered leaves a
remaining distance of 78.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.29 minutes
for a distance of 78.00 (Ft.) and a slope of 1.06 %
with an elevation difference of 0.83(Ft.) from the end of the top area
Tt = [11.9*length(Mi)'3)/(elevation change(Ft.))]A.385 *60(min/hr)
= 1.286 Minutes
Tt=[(11.9*0.0148"3)/( 0.83)]'.385= 1.29
Total initial area Ti = 3.14 minutes from Figure 3-3 formula plus
1.29 minutes from the Figure 3-4 formula = 4.43 minutes
Calculated TC of 4.427 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.114(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 0.805(CFS)
Total initial stream area = 0.130 (Ac.)
++++++++++++++.+++++++++++++++++++++++++++++++++++++++++++++++++++++++
3
Process from Point/Station 11.000 to Point/Station
PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 23.440(Ft.)
Downstream point/station elevation = 19.860(Ft.)
Pipe length = 420.00(Ft.) Slope = 0.0085 Manning's
No. of pipes = 1 Required pipe flow = 0.805(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 0.805(CFS)
Normal flow depth in pipe = 4.64(In.)
Flow top width inside pipe = 9.00(In.)
Critical Depth = 4.91(In.)
Pipe flow velocity = 3.50(Ft/s)
Travel time through pipe = 2.00 mm.
Time of concentration (TC) = 6.43 mm.
12.000
N = 0.013
Process from Point/Station 11.000 to Point/Station 12.000
SUBAREA FLOW ADDITION
Rainfall intensity (I) = 6.051(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 = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Time of concentration = 6.43 mm.
Rainfall intensity = 6.051(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.870 CA = 0.383
Subarea runoff = 1.512(CFS) for 0. 310 (Ac
Total runoff = 2.316(CFS) Total area = 0.440(Ac.)
+++++++++++++++++++++++++++++++++++4-++++++++++++++++++++++++++++++++++
Process from Point/Station 15.000 to Point/Station 16.000
INITIAL AREA EVALUATION
group A = 0.000
group B = 0.000
group C = 1.000
group D = 0.000
Decimal fraction soil
Decimal fraction soil
Decimal fraction soil
Decimal fraction soil
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai
Sub-Area C Value = 0.
Initial subarea total
Highest elevation =
= 0.950
870
flow distance = 89.000(Ft.)
27.900 (Ft.)
4
Lowest elevation = 27.000(Ft.)
Elevation difference = 0.900(Ft.) Slope = 1.011 %
Top of Initial Area Slope adjusted by User to 1.000 %
Bottom of Initial Area Slope adjusted by User to 1.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.21 minutes
TC = [1.8*(1.1_C)*distance(Ft.)'.5)/(% slope"(1/3)]
TC= [1.8*(1.1_0.8700)*( 60.000".5)/( 1.000A(1/3)1= 3.21
The initial area total distance of 89.00 (Ft.) entered leaves a
remaining distance of 29.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.61 minutes
for a distance of 29.00 (Ft.) and a slope of 1.00 %
with an elevation difference of 0.29(Ft.) from the end of the top area
Tt = [11.9*length(Mi)'3)/(elevation change(Ft.))]'.385 *60(min/hr)
= 0.615 Minutes
Tt=[(11.9*0.0055"3)/( 0.29)]A.385= 0.61
Total initial area Ti = 3.21 minutes from Figure 3-3 formula plus
0.61 minutes from the Figure 3-4 formula = 3.82 minutes
Calculated TC of 3.821 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.114(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 0.743(CFS)
Total initial stream area = 0.120(Ac.)
Process from Point/Station 16.000 to Point/Station 17.000
PIPEFLOW TRAVEL TIME (Program estimated size) ****
Upstream point/station elevation = 24.920(Ft.)
Downstream point/station elevation = 20.890(Ft.)
Pipe length = 503.00(Ft.) Slope = 0.0080 Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.743(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 0.743(CFS)
Normal flow depth in pipe = 4.51(In.)
Flow top width inside pipe = 9.00(In.)
Critical Depth = 4.71(In.)
Pipe flow velocity = 3.36(Ft/s)
Travel time through pipe = 2.50 mm.
Time of concentration (TC) = 6.32 mm.
Process from Point/Station 16.000 to Point/Station 17.000
SUBAREA FLOW ADDITION
Rainfall intensity (I) = 6.116(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 = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type - -
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Time of concentration = 6.32 mm.
Rainfall intensity = 6.116(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.870 CA = 0.783
Subarea runoff = 4.046(CFS) for 0. 780 (Ac.
Total runoff = 4.789(CFS) Total area = 0.900(Ac
Process from Point/Station 20.000 to Point/Station 21.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 200.000(Ft.)
Highest elevation = 60.000(Ft.)
Lowest elevation = 58.000(Ft.)
Elevation difference = 2.000(Ft.) Slope = 1.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.00 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.21 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)]
TC= [1.8*(l.1_0.8700)*( 60.000A.5)/( 1.000"(1/3)1= 3.21
The initial area total distance of 200.00 (Ft.) entered leaves a
remaining distance of 140.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 2.07 minutes
for a distance of 140.00 (Ft.) and a slope of 1.00 %
with an elevation difference of 1.40(Ft.) from the end of the top area
Tt = [11.9*length(Mi)P3)/(elevation change(Ft.))J'.385 *60(min/hr)
= 2.066 Minutes
Tt=[(11.9*0.0265'.3)/( 1.40)]A.385= 2.07
Total initial area Ti = 3.21 minutes from Figure 3-3 formula plus
2.07 minutes from the Figure 3-4 formula = 5.27 minutes
Rainfall intensity (I) = 6.874(In/Hr) for a 100.0 year storm
6
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.615(CFS)
Total initial stream area = 0.270(Ac.)
Process from Point/Station 21.000 to Point/Station 22.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 43.500(Ft.)
Downstream point elevation = 39.600(Ft.)
Channel length thru subarea = 378.000(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' = 0.018
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 4.622(CFS)
Depth of flow = 0.219(Ft.), Average velocity =
Channel flow top width = 21.935(Ft.)
Flow Velocity = 1.92(Ft/s)
Travel time = 3.28 mm.
Time of concentration = 8.55 mm.
Critical depth = 0.221(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 5.032(In/Hr) for a
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
Rainfall intensity = 5.032(In/Hr) for a
Effective runoff coefficient used for total
(Q=KCIA) is C = 0.870 CA = 1.505
4.622 (CFS)
1. 921(Ft/s)
100.0 year storm
100.0 year storm
area
Subarea runoff = 5.959(CFS) for 1.460(Ac.)
Total runoff = 7.574(CFS) Total area = 1.730(Ac.)
Depth of flow = 0.264(Ft.), Average velocity = 2.174(Ft/s)
Critical depth = 0.270(Ft.)
Process from Point/Station 25.000 to Point/Station 26.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
7
[INDUSTRIAL area type
(General Industrial
Impervious value, Al = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 76.000(Ft.)
Highest elevation = 60.000(Ft.)
Lowest elevation = 59.200(Ft.)
Elevation difference = 0.800(Ft.) Slope = 1.053 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 60.00 (Ft)
for the top area slope value of 1.05 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.15 minutes
TC = [1.8*(1.1_C)*distance(Ft. ).".5)I(% slope "(1/3)]
TC= [1.8*(1.1_0.8700)*( 60.000".5)/( 1.053"(1/3)]= 3.15
The initial area total distance of 76.00 (Ft.) entered leaves a
remaining distance of 16.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.38 minutes
for a distance of 16.00 (Ft.) and a slope of 1.05 %
with an elevation difference of 0.17(Ft.) from the end of the top area
Tt = [11.9*length(Mi)"3)/(elevation change(Ft.))]A.385 *60(min/hr)
= 0.381 Minutes
Tt=[(11.9*0.0030.3)/( 0.17)]".385= 0.38
Total initial area Ti = 3.15 minutes from Figure 3-3 formula plus
0.38 minutes from the Figure 3-4 formula = 3.53 minutes
Calculated TC of 3.533 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.114(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 1.052(CFS)
Total initial stream area = 0.170 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 26.000 to Point/Station 27.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 43.300(Ft.)
Downstream point elevation = 39.800(Ft.)
Channel length thru subarea = 603.000(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
Manning's 'N' = 0.018
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 1.052(CFS)
Depth of flow = 0.140(Ft.), Average velocity = 1.069(Ft/s)
Channel flow top width = 14.027 (Ft.)
Flow Velocity = 1.07(Ft/s)
Travel time = 9.40 mm.
Time of concentration = 12.93 mm.
8
Critical depth = 0.122(Ft.)
Process from Point/Station 27.000 to Point/Station 28.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 39.800(Ft.)
Downstream point elevation = 36.800(Ft.)
Channel length thru subarea = 600.000(Ft.)
Channel base width = 6.000(Ft.)
Slope or 'Z' of left channel bank = 3.000
Slope or 'Z' of right channel bank = 3.000
Estimated mean flow rate at midpoint of channel =
Manning's 'N' = 0.030
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 5.058(CFS)
Depth of flow = 0.408(Ft.), Average velocity =
Channel flow top width = 8.446(Ft.)
Flow Velocity = 1.72(Ft/s)
Travel time = 5.82 mm.
Time of concentration = 18.75 mm.
Critical depth = 0.268(Ft.)
Adding area flow to channel
Rainfall intensity (I) = 3.032(In/Hr) for a
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Ai = 0.950
Sub-Area C Value = 0.870
5.058(CFS)
1.717 (Ft/s)
100.0 year storm
Rainfall intensity = 3.032(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.870 CA = 2.967
Subarea runoff = 7.944(CFS) for 3.240(Ac.)
Total runoff = 8.997(CFS) Total area = 3.410(Ac.)
Depth of flow = 0.565(Ft.), Average velocity = 2.069(Ft/s)
Critical depth = 0.383(Ft.)
Process from Point/Station 30.000 to Point/Station 31.000
INITIAL AREA EVALUATION
group A = 0.000
group B = 0.000
group C = 1.000
group D = 0.000
Decimal fraction soil
Decimal fraction soil
Decimal fraction soil
Decimal fraction soil
[INDUSTRIAL area type
(General Industrial
9
Impervious value, Al = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 282.000(Ft.)
Highest elevation = 42.900(Ft.)
Lowest elevation = 31.400(Ft.)
Elevation difference = 11.500(Ft.) Slope = 4.078 %
Top of Initial Area Slope adjusted by User to 4.043 %
Bottom of Initial Area Slope adjusted by User to 4.043 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 90.00 (Ft)
for the top area slope value of 4.04 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.47 minutes
TC = [1.8*(1.1_C)*distance(Ft.)".5)/(% slope"(1/3))
TC= [1.8*(1.1_0.8700)*( 90.000'.5)/( 4.043"(1/3)1= 2.47
The initial area total distance of 282.00 (Ft.) entered leaves a
remaining distance of 192.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.54 minutes
for a distance of 192.00 (Ft.) and a slope of 4.04 %
with an elevation difference of 7.76(Ft.) from the end of the top area
Tt = [11.9*length(Mi)A3)/(elevation change(Ft.))].385 *60(min/hr)
= 1.539 Minutes
Tt=[(11.9*0.03643)/( 7.76)]A.385= 1.54
Total initial area Ti = 2.47 minutes from Figure 3-3 formula plus
1.54 minutes from the Figure 3-4 formula = 4.00 minutes
Calculated TC of 4.004 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 7.114(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 4.951(CFS)
Total initial stream area = 0.800 (Ac.)
Process from Point/Station 35.000 to Point/Station 36.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 1.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(General Industrial
Impervious value, Al = 0.950
Sub-Area C Value = 0.870
Initial subarea total flow distance = 539.000(Ft.)
Highest elevation = 41.400(Ft.)
Lowest elevation = 28.300(Ft.)
Elevation difference = 13.100(Ft.) Slope = 2.430 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
10
for the top area slope value of 2.43 %, in a development type of
General Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.58 minutes
TC = [1.8*(1.1_C)*distance(Ft.)'.5)/(% slope'(1/3)]
TC= [1.8*(1.1_0.8700)*( 70.000".5)/( 2.430"(1/3)1= 2.58
The initial area total distance of 539.00 (Ft.) entered leaves a
remaining distance of 469.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 3.72 minutes
for a distance of 469.00 (Ft.) and a slope of 2.43 %
with an elevation difference of 11.40(Ft.) from the end of the top area
Tt = [11.9*length(Mi)'*3)/(elevation change(Ft.))]'.385 *60(min/hr)
= 3.723 Minutes
Tt=[(11.9*0.0888A3)/( 11.40)]".385= 3.72
Total initial area Ti = 2.58 minutes from Figure 3-3 formula plus
3.72 minutes from the Figure 3-4 formula = 6.30 minutes
Rainfall intensity (I) = 6.129(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.870
Subarea runoff = 2.079(CFS)
Total initial stream area = 0.390 (Ac.)
+.+++++++++++++++++++++++++++++++++++++++++++++++++++++++.+.++++++++.+
Process from Point/Station 40.000 to Point/Station 41.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 1.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
[LOW DENSITY RESIDENTIAL
(2.0 DU/A or Less
Impervious value, Ai = 0.200
Sub-Area C Value = 0.340
Initial subarea total flow distance = 339.000(Ft.)
Highest elevation = 28.400(Ft.)
Lowest elevation = 22.500(Ft.)
Elevation difference = 5.900(Ft.) Slope = 1.740 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 1.74 %, in a development type of
2.0 DU/A or Less
In Accordance With Figure 3-3
Initial Area Time of Concentration = 10.49 minutes
TC = [1.8*(1.1_C)*distance(Ft. )".5)/(% slope "(1/3)]
TC = [1.8*(1.1_0.3400)*( 85.000'.5)/( 1.740'(1/3)]= 10.49
The initial area total distance of 339.00 (Ft.) entered leaves a
remaining distance of 254.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 2.64 minutes
for a distance of 254.00 (Ft.) and a slope of 1.74 %
with an elevation difference of 4.42(Ft.) from the end of the top area
Tt = [11.9*length(Mi)'3)/(e1evation change(Ft.))]".385 *60(min/hr)
= 2.641 Minutes
Tt=[(11.9*0.0481A3)/( 4.42)].385= 2.64
Total initial area Ti = 10.49 minutes from Figure 3-3 formula plus
2.64 minutes from the Figure 3-4 formula = 13.13 minutes
Rainfall intensity (I) = 3.817(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.340
Subarea runoff = 0.130(CFS)
Total initial stream area = 0.100(Ac.)
End of computations, total study area = 8.700 (Ac.)
12
APPENDIX B
00-YEAR WSPGW ANALYSES
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LEGEND:
MAJOR DRAINAGE BASIN BOUNDARY
MINOR DRAINAGE BASIN BOUNDARY
OVERLAND FLOW PATH
PROPOSED DRAINAGE FACILITY
3.62 AC DRAINAGE BASIN AREA
11?fl RATIONAL METHOD NODE NUMBER
PROPOSED OPEN AIR CORRIDOR
PROPOSED ROOF EXPANSION
7, <AIIUNAL MIhUD WUhcK MAF-'
SDP 09-04 (A) I
GENBZ& NOTES:
PROPOSED TORM DRAINS SERVING OPEN AIR CORRIDOR4I(BLUE( \
1. EXISTING UPLITES ARE BASED ON ORAWNC NUMBERS 269-7, 805-3 & 805-6.
:~~GROUTED RiPPAP EXACT ALIGNMENT AND DEPTH OF U77LIPES WILL BE DETERMINED By
WSPGW STATI S FQRCENTRAL AND EAST SYSTEIV11i
UNDERGROUND INVESTIGATIONS PRIOR TOCONSTRUCTION.
— I Z MONUMENT To8E RELOCATED. PLACEMENT SIGNS TOREDETERMINED PURSUANT ~O 7HE WESTRELD CARLSBAD SIGN PROGRAM. FEMAFLOODZO
J. EXACT PLACE04ENT OF LIGHT STANDARDS AND OTHER SIGN FIXTURES IS SUBJECT TO A DETAILED LiGH71NG PLAN THAT SHALL BE APPROVED PRIX TO ISSUANCE
C) RI RE A BUILDING PERMIT OR GRADING PERMIT, I%RICHEHER OCCURS FIRST. MAP 3C0762 F
4 FIRE SPRINKLER SYSTEMS ARE REWIRED FIRE SPRINKLERS ARE To BE TX. SSMH
DES/SPED / TO NFPA /3 STANDARDS BY FIRE SPRINKLER CONSULTANT. ((E 4.501 OUT)
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EXS 1/NO ITEM TO REMAIN, P1/UT/CT IN PLACE -
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