HomeMy WebLinkAboutDEV 2017-0074; ROYAL JET HANGER EXPANSION; DRAINAGE STUDY; 2017-10-01OCT 03 2017
LAND DEVELOPMENT
ENGINEERING
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DRAINAGE STUDY
for
ROYAL JET REMODEL
REMOVAL & REPLACEMENT OF EXISTING HANGAR
2220 Palomar Airport Rd., Carlsbad, CA, 92011
Proj. ID: DEV2017-0074
Dwg. No.: 503-6A
Prepared for:
Department of Public Works, Airports
County of San Diego
1560 Joe Crosson Dr.
El Cajon, CA 92020
(619) 956-4819
Prepared by:
Consultants, Inc.
Bruce A. Robertson
REC Consultants, Inc.
2442 Second Avenue
San Diego, CA 92101
619-232-9200
ESSi,
k\125' 6/30/18 7
or C
Report Prepared:
October 1, 2017
TABLE OF CONTENTS
Chapter 1 - Executive Summary...........................................................................................................1
1.1 Introduction ..............................................................................................................................
.
........................ 1
Project Site ........................................................................................................................................................1
PrimaryConsiderations .....................................................................................................................................1
Pointof Comparison ..........................................................................................................................................1
Rationale for Analysis of Run-On Areas ............................................................................................................ 1
FloodZone .............................. .......................................................................................................................... 1
1.2 Summary of Pre-Development Conditions......................................................................................................2
1.3 Summary of Post- DevelopmEnt Conditions .....................................................................................................2
— 1.4 Summary of Hydrology Results .............................................................................................. ......................... 3
RationalMethod Results ...................................................................................................................................3
- Modified Rational Method Results ..................................................................................................................... 3
PeakFlow Comparison ......................................................... .............................................................................. .4
1.5 Summary of Hydraulics Results ......................................................................................................................4
StormDrain Pipes..............................................................................................................................................4
StormDrain Channels .......................................................................................................................................5
1.6 References ......................................................................................................................................................5
1.7 Declaration of Responsible Ciarge ................................................................................................................. 6
Chapter2 — Methodology ....................................................................................................................... 7
2.1 Design Criteria ....................... . .......................................................................................................................... 7
2.2 Hydrology ......................................................................................................................................................... 7
Rational Method ....................... ........................................................................................................................... 7
RunoffCoefficient (C) ........................................................................................................................................7
Timeof Concentration
RainfallIntensity (I)............................................................................................................................................7
(ta) .................................................................................................................................. 8
2.3 Hydraulics ........................................................................................................................................................ 9
GratedInlets in Sag ........................................................................................................................................... 9
Pipesand Channels ........................................................................................................................................... 9
Chapter 3 - Conclusions........................................................................................................................9
APPENDIX A: Maps & Details
APPENDIX B: Calculations
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CHAPTER 1 - EXECUTIVE SUMMARY
1.1 Introduction
Proiect Site
The project site is located along the southern edge of Palomar Airport at 2200 Palomar Airport Rd, City of Carlsbad, County of
San Diego, California. The project site is bound by Palomar Airport Road to the south and the existing airport to the north, east
and west. The project site is a leasehold property with a total area of approximately 1.37 acres; however, the total area
analyzed for this study is 4.01 acres, which includes 2.95 acres of existing run-on areas and 1.06 acres of disturbed area
within the project site. The proposed site improvements include proposed building extensions to the western and eastern sides
of the existing airplane hangar and the removal, regrading, and replacements of pavement on site. Proposed impervious areas
will drain to two (2) proposed Biofiltration Best Management Practices (BMP), which will treat runoff for water quality purposes,
detain low flows for hydromodification purposes, and manage larger flows for flood control purposes.
Primary Considerations
This study analyzes pre- and post-development 100-yr peak flow rates (Qioo).
Treatment of storm water runoff for Pollutant Control and Hydromodification from the site has been addressed in a separate
report - the "Storm Water Quality Management Plan for Royal Jet Aircraft Hangar" dated June 2017 by REC Consultants.
Per the San Diego County Hydrology Manual (SDCHM), the Rational Method is recommended for analyzing the runoff
response from drainage areas up to approximately I square mile in size. Hand calculations were used to model the pre- and
post-development condition runoff response.
Methodologies pertaining to the Hydrology of the site are consistent with Chapter 3 (Rational Method & Modified Rational
Method) of the SDCHM. Methodologies pertaining to the Hydraulic design of the site improvements are consistent with the
San Diego County Hydraulic Design Manual (2014).
Point of Comparison
For drainage analysis, one (1) point of comparison, denoted as POC-1, has been designated within an existing concrete swale
approximately 30 feet north of the southeast corner project site boundary. From POC-1, flows continue east along an existing
concrete swale that terminates at an existing catch basin, which conveys flows to the public storm drain system.
Rationale for Analysis of Run-On Areas
In the existing condition, 2.95 acres of impervious area produces runoff that crosses the project site and terminates at POC-1.
In the proposed condition, storm water discharge from the run-on areas, designated RI & R2, were routed around the project
site via storm drain facilities. The hydrologic analysis of Ri & R2 and subsequent hydraulic analysis of the proposed storm
drain facilities were required to sufficiently size proposed facilities. Furthermore, there is minimal impact in the run-on areas
due to the proposed improvements; therefore, there is no expected appreciable increase in runoff contribution from Ri & R2 to
POC-1. As a result, Ri & R2 are excluded from the comparison of flows at POC-I.
Flood Zone
Per FEMA Flood Insurance Map 06073C1610G (revised May 16, 2012), the project site resides in Zone X, indicating that the
site is an area determined to be outside the 0.2% annual chance floodplain.
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1.2 Summary of Pre-Development Conditions
In the pre-development condition, there is a single contributing drainage management area (DMA), denoted as El, that
ultimately discharges to P00-1.
El has an area of 46,173 sf (1.06 ac), length of 160 ft, slope of 4%, and impervious area fraction of 97%. El generally drains
north to south discharging to a concrete swale that terminates at POC-l. El consists of the existing hangar to be remodeled,
asphalt and concrete pavement, and landscaping.
There are two (2) DMAs, Ri & R2, that produce storm water runoff that comingles with discharge from El in the existing
condition. Runoff from Ri, R2 and El ultimately confluences downstream of P00-1.
Ri is an existing DMA that drains north to south and terminates at El. Ri has a total area of 90,785 sf (2.08 ac), length of 192
ft, slope of 2%, and impervious fraction of 100%. Ri consists of an existing building to the northwest of the site, asphalt travel
lanes and parking fields. Runoff from Ri flows onto El.
R2 is an existing DMA that drains west to east and terminates at El. R2 has a total area of 37,613 sf (0.86 ac), length of 156
ft, slope of 2%, and impervious fraction of 100%. R2 consists of two existing buildings to the west of the site, asphalt travel
- lanes and parking fields. Runoff from R2 flows onto El.
U 1.3 Summary of Post-Development Conditions
See Appendix for a detailed view of the DMAs and private storm drain improvements described in this section.
The proposed site alters drainage patterns by introducing ridges, depressions, and storm drain infrastructure to divide the
contributing drainage area to P00-1 into two (2) DMAs, denoted as Ni & N2.
I Ni drains north to south. Ni's land cover consists of concrete pavement, the western hangar extension and the existing
hangar. Ni outlets to a proposed Biofiltration BMP, denoted BMP-1. Ni has a total area of 38,960 sf (0.894 ac); length of 192
ft, slope of 3.5% and impervious fraction of 99.6%. BMP-i at the outlet of Ni has an area of 1153 sf; runoff from Ni is
I managed by a low flow orifice within the gravel layer of BMP-1 and a grated catch basin that acts as a weir for larger flows.
Flows from the catch basin outlet via a proposed 12" PVC storm drain pipe that terminates at a proposed 24" RCP storm drain
pipe to the south, confluencing with runoff from R2.
I N2 drains west to east. N2's land cover consists of concrete pavement as well as the eastern extension of the existing hangar;
all impervious areas drain to landscaping and ultimately to a proposed Biofiltration BMP, denoted BMP-2. N2 has a total area
of 5,586 sf (0.128 ac); length of 156 ft, sl ope of i% and impervious fraction of 98.8%. BMP-2 at the outlet of N2 has an area of
I 474 sf; runoff from N2 is managed by a low flow orifice within the gravel layer of BMP-2 and a grated catch basin that acts as
a weir for larger flows. Flows from the catch basin outlet via a 6" PVC storm drain pipe that terminates at P00-1, confluencing
with flows from Ni & R2.
I Ri remains relatively undisturbed and outlets to a proposed trench drain along Ri's southern edge. The trench drain, flowing
west to east, outlets directly to a 24" diameter pipe. The trench drain outlets to an existing 24" RCP approximately 35' south of
the northeast corner of the project site. Runoff from Ri eventually confluences with flows from Ni, N2 & R2 downstream of ' P00-i.
R2 remains relatively undisturbed and outlets to a proposed trench drain along R2's eastern edge. The trench drain, flowing
north to south, outlets directly to an 18' diameter pipe. The trench drain outlets to a proposed 18" RCP to the south of the
disturbed area, which ultimately flows east to P00-11 as described previously.
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1.4 Summary of Hydrology Results I Rational Method Results
To determine the 100-yr runoff for each DMA, the Rational Method was performed for all the pre- and post-development
DMAs. The following table outlines the results from the analysis. Please note that if tc is less than or equal to 5 minutes, a t of
5 minutes was used per the Hydrology Manual to analyze Qioo.
Table I. Rational Method Results
DMA tc
min
A
ac
Q100
cfs
Pre-Development Area
El 5 1 1.06 1 6.67
Run-on Areas (Undisturbed)
RI 5 2.08 13.34
R2 5 0.86 5.53
Post-Development Areas
NI 5 0.89 5.71
N2 5 0.13 0,82
The disparity between El and the sum of Ni & N2 is the sum of the BMP areas, which is 1,626 sf (0.04 ac).
Modified Rational Method Results
I To determine the hydrologic impact of the development, Q100 for El was compared with the confluence of Ni & N2, which was
determined by a Modified Rational Method (MRM) analysis. The results of the analysis are shown in Table 2 below.
Table 2. Post-Development Flows at POC-I
DMA tc
min
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in/hr
Qioo
cfs
QT
cfs
Ni 5 7.11 5.71 6.53
N2 5 7.11 0.82 6.53
Qioo 6.53 cfs
t 5 mm
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Peak Flow Comparison
Table 3 below outlines the comparison of Qioo for the existing and proposed conditions, indicating that the proposed condition
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mitigates an increase in runoff while increasing time of concentration. The decrease in Qioo can be attributed to the slight
increase in pervious area due to the proposed BMPs in post-development conditions. The increase in t is likely the result of
- shallower slopes in the proposed condition. The Modified Rational Method analyses results in a decrease of Qioo in the post-
development condition; therefore, it was not apt to perform a routing analysis.
Table 3. Peak Flow Comparison Summary
Condition A
ac
Tc
min
Q
cfs
Pre-Development 1.06 5 6,67
Post-Development 1 1.06 1 5 1 6.53
Change 0.00 0.00 -0.14
% Difference 0.00 0.0% -2.1%
1.5 Summary of Hydraulics Results
See Appendix A to see the storm drain layout for the project site.
Storm Drain Pipes
There are nine (9) proposed private storm drain pipes, denoted as P1 through P9. The following table summarizes the storm
drain pipe properties and flow depths corresponding to post-development Qioo.
Table 4.Manning's Equation Results for Proposed Pipes
Pipe Upstream
DMAs
Q100
cfs
d
in
n h
in
Ix
ff2
P
ft
R
ft
S
ft/ft
v
ft/s
P1 R2 5.53 18 0.013 9.7 0.98 2.48 0.39 085% 5.7
P2 R2 5.53 18 0.013 6.3 0.55 1.90 0.29 4.1% 10.1
P3 NI 5.71 12 0.013 6.0 0.40 1.58 0.25 10.0% 14.4
P4 Ni 5.71 12 0.013 5.2 0.33 1.43 0.23 17.1% 17.6
P5 NI +R2 11.24 18 0.013 9.3 0.93 2.41 0.38 4,05% 12.1
P6 N2 0.82 6 0.013 3.1 0.10 0.80 0.13 7.9% 8.1
P7 Ni +N2
+R2 12.06 24 0.013 14.9 2.05 3.63 0.56 0.6% 5.9
P8 Ri 13.34 24 0.013 16.0 2.22 3.81 0.58 0.6% 6.0
P9 Ri 13.34 24 0.013 6.8 0.73 2.24 0.33 11.5% 18.3
Where: d = diameter of pipe (in);
n = Manning's roughness coefficient = 0.013 (per San Diego County Hydraulic Design Manual);
S = pipe slope (ft/ft);
h = flow depth (ft);
AX = cross-sectional area of flow (ft2);
P = wetted perimeter (ft);
R = hydraulics radius (ft); and,
v = flow velocity (ftls)
Where erosive flows may occur, e.g. pipes flowing to BMPs, downstream riprap energy dissipaters and headwalls have been
employed (see Appendix A).
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Storm Drain Channels
There are two (2) storm drain channels that convey flow from minor areas within their respective contributing DMAs. The
following table summarizes the storm drain channel properties and flow depths corresponding to post-development Qioo.
Table 5. Manning's Equation Results for Proposed Channels
Channel Upstream
DMAs
Qioo
cfs
H
ft
W
ft
n h
ft
Fb
ft
A
ft2
P
ft
R
ft
S
ft/ft
v
ft/s
DI Part of NI 0.06 0.5 2.0 0.015 0.06 0.44 0.03 0.68 0.04 3.8% 2.2
D2 Part ofN2 0.47 0.5 2.0 0.015 0.18 0.32 0.15 1.27 0.12 1.9% 3.2
Where: H = max depth of channel (ft);
W = max top width of channel (ft);
n = Manning's roughness coefficient = 0.015 (per San Diego County Hydraulic Design Manual);
h = flow depth (ft);
Fb = available freeboard (ft);
AX = cross-sectional area of flow (ft2);
P = wetted perimeter (ft);
R = hydraulics radius (ft);
S = channel slope (ft/ft); and,
v = flow velocity (ftls)
As Table 5 indicates, all channels are sufficiently sized to convey Qioo flows in post-development condition. Qioo for the
channels were determined by assuming a time of concentration of 5 minutes, since the areas are relatively small and are
unlikely to yield a t larger than 5 minutes.
1.6 References
San Diego County Hydrology Manual, 2003
San Diego County Hydraulic Design Manual, 2014
City of Carlsbad BMP Design Manual (2016)
USDA Websoil Survey
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1.7 Declaration of Responsible Charge
I hereby declare that I am the Engineer of Work for this project, that I have exercised responsible charge over the design of
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the project as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with current
standards.
I understand that the check of project drawings and specifications by the County of San Bernardino is confined to a review
only and does not relieve me, as Engineer of Work, of my responsibilities for project design.
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Bruce A. Robertson, R.C.E. 48529
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CHAPTER 2- METHODOLOGY
All calculations per the Methodology described in this section can be found in Appendix B.
2.1 Design Criteria
Per section 6.2.1 of the San Diego Hydraulic Design Manual:
"Where there are undersized facilities downstream and when a basin is being used to mitigate post project
downstream impacts, the basin capacity and outlet shall be designed such that the post-project peak flow rate shall
be less than or equal to the pre-project flow rate for all frequency storms up to and including the 100-yr event."
For water quality and hydromodification purposes, we have employed Biofiltration BMPs (i.e. basins) to manage and treat
flows; therefore, the above provision pertains to this project and we demonstrate that the requirement is fulfilled by mitigating
the 100-yr peak event while negligibly impacting the time of concentration.
2.2 Hydrology
All methods in the "Hydrology" section comply with the San Diego County Hydrology Manual (2003), hereafter referred to as
"Hydrology Manual". Per the Section 2.3, the Rational Method or Modified Rational Method shall be used for drainage areas
between 0 and 1 square-mile.
Rational Method
The Rational Method was performed per Section 3 of the Hydrology Manual and was applied for the existing and proposed
conditions. The equation for the Rational Method is as follows.
Q = CIA (Equation 1) 1 Where: Q = peak flow rate (cfs);
= peak rainfall intensity (in/hr); and,
A = contributing drainage area (ac) 1
The Rational Method does not yield a hydrograph, it can only determine the maximum runoff flow rate for a design storm. For
this Drainage Study, the design storm is the 100-yr storm event.
Runoff Coefficient (C)
Per Section 3.1.2 of the Hydrology Manual, the runoff coefficient (C) represents the fraction of precipitation that becomes
runoff. For each drainage area, "C" was determined using the following equation.
I = 0.90a + Ca (Equation 2)
Where: C = dimensionless runoff coefficient;
ai = impervious fraction of contributing area = (impervious area within DMA) I (total DMA area);
Cp = dimensionless runoff coefficient for pervious areas, 0.35 for soil type D per Table 3-1 of the Hydrology
Manual; and,
pervious fraction of the contributing area = 1 - a
From the USDA Websoil Survey, it was determined that the site was underlain with soil designated as Hydrologic Soil Group
(HSG) D.
Rainfall Intensity (I)
Per Section 3.1.3 of the Hydrology Manual, peak rainfall intensity (I) represents the rate at which precipitation falls within a
given time increment. "I" can be determined using the following equation.
I = 7.44P6 t-0.641 (Equation 3)
Where: I = peak rainfall intensity (in/hr);
P6 = adjusted 6-hr rainfall for a given storm event (in); and,
= time or duration (mm) (if t is less than 5 mins, use 5 mins in determining peak Q)
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I For the Rational Method, we are concerned with the peak "I"; therefore, "t" is the time of concentration (ta) (explained below)
for the 100-yr storm event. Per Figure 3-1 in the Hydrology Manual, t has a minimum value of 5 minutes.
The 100-yr "P6' value can be found using the Rainfall Isopluvials in the Hydrology Manual. As mentioned above, P6 is an
adjusted value; P6 must be greater than or equal to 45% and less than or equal to 65% of the 24-hr precipitation (P24). P24 can
also be determined using the provided isopluvials in the Hydrology Manual.
I Time of Concentration (tl
Per Section 3.1.4, the time of concentration (ta) refers to the time it takes for runoff from the most remote point within the
watershed to reach the outlet. The time of concentration can be determined using the following equation.
I tc = tC + tt (Equation 4)
Where: t time of concentration (mm),
I td = initial time of concentration (mm) = 1.8*(1.1 - C)*L1/2 / S113 (from Figure 3-3 in Hydrology Manual);
C = dimensionless runoff coefficient of the initial area;
L = distance for sheet flow to become concentrate flow (ft);
s = slope of initial area (%); and,
1 tt = travel time of concentrated flow (mm)
- As Equation 3 indicates, tc consists of an initial time of concentration (t1) and travel time (ti). The initial time of concentration
I represents the duration associated with initial precipitation that becomes runoff to concentrate from sheet flow. "t1" is
dependent on impervious fraction (ai) and slope of the initial subarea (see Table 3-2 of the Hydrology Manual).
Travel time (ti) is the estimated time it takes for flow to travel along the flow path. It is estimated by dividing the average flow
:I velocity (v) into the flow length per the following equation.
= (Equation 5)
1 Manning's equation (shown below) was applied to determine the flow velocity along the flow path.
Q = (Equation 6)
Where: Q = pipe flow (cfs),
n = Manning's roughness coefficient = 0.013 (per San Diego County Hydraulic Design Manual);
A = cross-sectional area of flow (ft2)
R = hydraulic radius (ft) = NP;
P = wetted perimeter (ft); and,
S = pipe slope (ft/ft)
[;]
2.3 Hydraulics
All methods in the "Hydraulics" section comply with the San Diego County Hydraulic Design Manual (2014), hereafter referred
to as "Hydraulics Manual".
Grated Inlets in Sag
BMP-i and BMP-2 have grates to manage large flows. Per the "Grated Inlets in Sag" section in Chapter 2 of the Hydraulics
Manual, the following equation can be used to determine the flow capacity of the grates flowing as weirs.
Q = CPd (Equation 7)
Where: Q = inlet capacity of the grated inlet (cfs),
CW = dimensionless weir coefficient = 3,0;
Pe = effective grate perimeter length (ft) = (1CL)*P;
CL = dimensionless clogging factor = 0.50;
P = actual grate perimeter (ft) = 18.4 ft (BMP-1) and 9.2 ft (BMP-2) (see below)
d = flow depth approaching inlet (ft) = 0.33' (BMP-1) and 0.25' (BMP-2) (see below)
A San Diego Regional Standard Drawing (SDRSD) D-15 grate has a perimeter length of 9.2 ft. BMP-i has an overflow catch
basin with two (2) D-15 grates, while BMP-2 only has one. The available head to BMP-i was determined to be 4(0.33') to
ensure that the post-development Qioo from Ni will be sufficiently conveyed. Furthermore, the available head to BMP-2 was
determined to be 3(0.25') to ensure that the post-development Qioo from N2 will be sufficiently conveyed.
Pipes and Channels
Sizing the proposed pipes and channels was performed using the Manning's Uniform Flow Equation shown in Equation 6. Per
Appendix A of the Hydraulics Manual, the following table outlines the 'n' values used in this study.
Table 6. Manning's Roughness Coefficient (n)
Surface I Conduit Material Reference n
Concrete Gutter Table A-i 0.015
Concrete Pavement Table A-i 0.014
Reinforced Concrete Pipe (RCP) Table A-2 0.013
Smooth Plastic Pipe (PVC) Table A-2 0.013
Air Blown Concrete (Channels) - 0.5-2' of flow depth Table A-3 0.019
CHAPTER 3- CONCLUSIONS
In conclusion, the proposed development is expected to reduce the total peak flow leaving the property by 2.1% while
mitigating a change to the time of concentration during the i 00-yr storm events. Furthermore, all hydraulic structures
employed in the site design have been sufficiently sized to convey their respective peak flows.
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APPENDIX A
Location Map
Pre-Development Drainage Area Map
Post-Development Drainage Area Map
Proposed BMP Details
USDA Websoil Survey Soil Map
(E) BUILDIP
N
L I\0.86 ac) -
I _ _
(E) BUILDING
----
/
09
LOCATION MAP 0 N TS
\
317
318
377 (E) HANGAR
1.06 ac) (317.4) FF
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/
RCP
I (E) CONCRETE
/ CHANNEL
5
76
Iiuutr:=,-j i
I I POC-1
[Q100 = 6.67 cfs
-
-
\/L(E)CONCRETE CHANNEL (E) CONCRETE---,
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LEGEND
(E): EXISTING; (N ): NEW/ PROPOSED
DMA LABEL
- - - - FLOW DIRECTION
DMA BOUNDARY
LEASEHOLD LINE
(PROPER I Y)
EXHIBIT NOTES
DMAsRi & R2 ARE UNDISTURBED RUN-ON
AREAS; ANALYZED FOR SIZING HYDRAULIC
STRUCTURES.
STRUCTURAL BMPS, BMP-1 & BMP-2, WERE
INCORPORATED TO MEET WATER QUALITY
& HYDROMODIFICATION REQUIREMENTS
FOR DMAs Ni & N2
ENTIRE SITE IS UNDERLAIN WITH
HYDROLOGIC SOIL GROUP 0
PER GEOTECH REPORT, NO
GROUNDWATER WAS ENCOUNTERED AT
21.5'.
TI IE SITE DOES NOT CONTAIN ANY
EXISTING NATURAL HYDROLOGIC
FEATURES (WATERCOURSES, SEEPS,
SPRINGS, WETLANDS)
THE SITE DOES NOT CONTAIN ANY
CRITICAL COARSE SEDIMENT YIELD AREAS
TO BE PROTECTED
I 60 30 0 60 120 180
PALOMAR AIRPORT ROAD
I SCALE: 1" = 60' App A.1 PRE-DEVELOPMENT DRAINAGE AREA MAP
ROYAL JET REMODEL
I I
t_ W~_.4
cl
-
p410_20
_
41 80 1211
--
__ SCALE: 1 _•
--
p5 71 /()18" RCP (SD)f
--
PALOMAR AIRPORT ROAD
( 0.8 c;)
\
P8
L (N) TRENCH DRAIN
ID I •. I -
Ni
p
0.66 ac
0 •;<./• Z ( 1
\O.6ay_ cl •\ P V. . /
p
'V
(N) BLDG
EXTENSION
317.4 FF
4
(E) HANGAR
(317.4) FF
\ II
N) IRENUHURAIN p
- -
i7
_
,1<
/
-
7-1 (N) 24 RCP (SD)
{P9\\
\
- N2
1(E) 24" RCP (SD)
013 /-(E) CONC. CHANNEL
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C2
v . I
2' -0 BMP-2
--4(N)6" PVC (SD)
Poc-1
P5 0100 = 6.53 cfs
\(N) HEADWALL
\(E) CONC. CHANNEL
DMA TYPE / NOTES
Ni DRAINS TO STRUCTURAL BMP - BIOFILTRATION BMP (BMP-1)
DRAINS TO STRUCTURAL BMP - BIOFILTRATION BMP (BMP-2) N2
Ri DRAINS TO PROPOSED TRENCH DRAIN - BYPASSES BMPs
R2 DRAINS TO PROPOSED TRENCH DRAIN - BYPASSES BMPs
EXHIBIT NOTES LEGEND
DMAs Ri & R2 ARE UNDISTURBED RUN-ON AREAS; SEE
PRE-DEVELOPMENT DRAINAGE AREA MAP
STRUCTURAL BMPS, BMP-1 & BMP-2, WERE INCORPORATED TO
MEET WATER QUALITY & HYDROMODIFICATION REQUIREMENTS FOR
DMAs Ni & N2
ENTIRE SITE IS UNDERLAIN WITH HYDROLOGIC SOIL GROUP D
PER GEOTECH REPORT, NO GROUNDWATER WAS ENCOUNTERED
AT 2i.5'.
THE SITE DOES NOT CONTAIN ANY EXISTING NATURAL HYDROLOGIC
FEATURES (WATERCOURSES, SEEPS, SPRINGS, WETLANDS)
THE SITE DOES NOT CONTAIN ANY CRITICAL COARSE SEDIMENT
YIELD AREAS TO BE PROTECTED
(E): EXISTING; (N): NEW/ PROPOSED
DMA LABEL
-. -. -- FLOW DIRECTION
DMA BOUNDARY
LIMITS OF WORK
LEASEHOLD LINE (PROPERTY)
PIPE LABEL
CHANNEL LABEL App A.2 POST-DEVELOPMENT DRAINAGE AREA MAP
ROYAL JET REMODEL
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SEE GRADING PLAN
OUTFALL PIPE SIZE-
PER GRADING PLAN
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SIN TOP AREA (SEE BMP TABLE)
BMP AREA (SEE BMP TABLE)
NJ BOTTOM AREA (SEE BMP TABLE) I
SDRSD D-08 CATCH BASIN 'T SEE "B" FOR TYPE
BA
I- BASI
PLANTING PER CITY
APPROVED PLANT LIST
[
PVC SCREW
CAP
IMPERMEABLE LINER
AROUND BMP
NON—PERFORATED
STANDPIPE
USE 45 WYE & FITTING OR
EQUIV. DIRECTIONAL
CLEANOUT TO CONNECT
UNDERDRAIN TO STANDPIPE
WATER TIGHT CAP ON
TERMINAL END OF PIPE
NOTES:
SOIL MIX PER CITY OF SAN DIEGO LID MANUAL
"WELL DRAINED SOIL" SHALL BE "SANDY LOAM" SOIL MIX WITH NO MORE
THAN 5% CLAY CONTENT. THE MIX SHALL CONTAIN 50-60% SAND,
20-30% COMPOST OR HARDWOOD MULCH, AND 20-30% TOPSOIL.
BEST MANAGEMENT PRACTICE (BMP) TABLE
BMP# BMP TYPE BASIN
TOP AREA
BMP
AREA
BASIN
BOT AREA
CATCH BASIN
TYPE
BMP-1 BIOFILTRATION (BF-1) 1313 SF 1153 SF 620 SF DOUBLE G-2
BMP-2 BIOFILTRATION (BF-1) 1 540 SF 474 SF 285 SF SINGLE G-1
I '
- SCH 40 MALE
ADAPTER (MiTPxSoC) CLASS II PERM ____ / SCH 40 PVC THREADED STORAGE LAYER
END CAP (FP 1)
PERFORATED 6" ° DRILL ORIFICE AT
FLOWLINE OF END CAP PVC UNDERDRAIN
(SEE TABLE TO RIGHT)
CLASS II PERM—/' I
STORAGE LAYER I
I J k
NATIVE SOIL LINED BASIN
I fflTH Th l
END CAP w/ FLOW CONTROL
ORIFICE PER DETAIL BELOW
TABULATED DATA
BMP1 BMP2
A 14" 9"
B DOUBLE G-2 SINGLE G-1
C 18" 18"
D 8" 8"
E
F 4" 4"
C 6" 6"
H 6" 6"
I 14" 9"
J 18" 12"
ORBMP IFICE
DIAMETER DIAMETER
7/8-
2 1 1/4"
ORIFICE DETAIL
N TS
App A.3 POST-DEVELOPMENT BMP & OUTLET DETAILS
ROYAL JET REMODEL
Hydrclogic Soil Group—San Diego County Area, California
(Palomar Airport HSG)
1
__
33 738" N _______ I
- 33 7 38" N
AL
I g
_
I I U -
V
i
'S
g
I
- - -
V - -
- - -
33 732"N
Ii
732" 8
I - V
4T4373
-
4 441~, 474430 4744E0
Map Se: 1:791 if pdnt ionAx)rtI-aIt(8.5'x 11') sheet.
MeLrs — N 0 10 20 40 60 I 0 35 70 140 210
Map paection Web Mercator Come- cooe1ina WGS84 Edge tss: UTM Zone uN WG584
I USDA Natural Resources Web Soil Survey 4/4/2017
Conservation Service Nat onal Cooperative Soil Survey Pagel oF 4
I Hydrologic Soil Group—San Diego County Area, California Palomar Airport HSG
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit - San Diego County Area, California (CA638)
Map unit symbol Map unit name Rating Acres in AOl Percent of AOl
LvF3 Loamy alluvial land- D 1.3 100.0%
Huerhuero complex, 9
to 50 percent slopes,
severely eroded
Totals for Area of Interest 1.3 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (AID, BID, and CID). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (AID, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 4/4/2017
Conservation Service National Cooperative Soil Survey Page 3 of 4
APPENDIX B
Hydrology Calculations
Hydraulics Calculations
Royal Jet Remodel
Hydrology Calculations
Precipitation
P6 2.1 in
P24 5.0 in
P6/P24 0.54
P6,adj 2.7 in
rre-ueveiojmepi i<a[ion' ivietno' uaicuiations
DMA A
sf
A
ac
L
ft
S
ft/ft
a,i C Li
ft
Ti
min
Ii
in/hr
Ai
sf
Qi
cfs
El 46173 1.06 160 0.040 0.97 0.88 65 1.97 7,11 4895 0.11
DMA hi
ft
zi Axi
ft2
Pi
ft
Ri
ft
n vi
ft/s
Qi
cfs
L2
ft
v2
I Ills
It
mm
El 0.08 50 0.29 1.7 0.04 0.014 2.4 0.71 95 4.7 0.44
DMA Tc
min
I
in/hr
Q
cfs
z2L z2R n2 h2
ft
Ax2
ft2
1
v2
ft/s
El 2.41 7.11 6.67 50 0.125 0.015 0.24 1 1.41 4.7
Ri in-nn Arpq Rf rnll Methnd (Thin iItinnc (fnr Hvdri ilinc ci7inn'
DMA A
sf
A
ac
L
ft
S
ft/ft
a,i C Li
ft
Ti
min
Ii
in/hr
Rl 90785 2.08 192 0.020 1.00 0.90 70 2.39 7.11
R2 37613 0.86 156 0.020 1.00 0.90 70 2.39 7.11
DMA hi
ft
zi Axi
ft2
P1
ft
Ri
ft
n vi
ft/s
I Qi
cfs
L2
ft
Rl 0.07 50 0.24 7.0 0.03 0.013 1.7 0.42 122
R2 0.05 50 0.10 4.5 0.02 0.013 1.3 0.13 86
DMA Ic
min
I
in/hr
Q
cfs
z2L z2R n2 h2
ft
Ax2
1t2
v2
ft/s
Rl 3.04 7.11 13.34 50 0.125 0.014 0.34 1 2.92 4.6
R2 3.02 1 7.11 5.53 1 50 50 0.013 0.18 1 1.68 3.3
Ai Qi
sf cfs
2874 0.42
905 0.13
v2 It
Ills mm
4.6 0.65
3.3 0.63
App B.l Hydrology Page 1 of 2
vos-ueveioIDmenr_auopi_iviernoa_aicuiauons
DMA A
sf
A
ac
L
ft
S
ft/ft
a,i C Li
ft
Ti
min
Ii
in/hr
Ai
si
Qi
cfs
Ni 38960 0.89 192 0.035 0.996 0.898 60 1.86 7.11 2874 0.42
N2 5586 0.13 156 0.010 0.988 0.893 60 2.88 7.11 905 0.13
DMA hi
ft
zi Axi
ft2
Pi
ft
Ri
I ft
n vi
ftis
Qi
cfs
[2
ft
v2
ft/s
It
mm
Ni 0.06 50 0.21 6.5 0.03 0.014 2.0 0,42 132 4.3 0.69
N2 0.05 50 0.14 5.3 0.03 0.014 0.9 0.13 96 1.7 1.23
DMA Tc
min
I
in/hr
Q
cfs
z2L z2R n2 h2
ft
Ax2
ft2
v2
ft/s
Ni 2.55 7.11 5.71 50 0.125 0.015 0.23 1.32 4.3
N2 4.11 7.11 0.82 50 0.125 0.015 0.14 0.49 1.]
I Calculations vosi-ueveiopmen_ivioair'eai<auonai ivietno
DMA Tc
min
I
in/hr
Q
cfs
QT
cfs
Ni 2.55 7.11 5.71 6.22
N2 4.11 7.11 0.82 6.53
Q 6.53 cfs
Tc 4.11 mm
0100 Comparison
Condition Tc
min
Q cfs
Pre-Development 2.41 6.67
Post-Development 4.11 6.53
Change 1.69 1 -0.14
% Difference 170.1%1 -2.1%
App B.i Hydrology Page 2 of 2
Mao - - IMM MM - - - - - - - M==M
Royal Jet Remodel
Hydraulics Calculations
Hydraulics Calculations (Pioe
Pipe Upstream
DMAs
Q100
cfs
d
in
n a
deg
h
in
Ax
ft2
P
ft
R
ft
S
ft/ft
v
ft/s
Grading Plan
Tags
P1 R2 5.53 18 0.013 189 9.7 0.98 2.48 0.39 0.85% 5.7 Li
P2 R2 5.53 18 0.013 145 6.3 0.55 1.90 1 0.29 4.05% 10.1 L2
P3 Ni 5.71 12 0.013 181 6.0 0.40 1.58 0.25 10% 14.4 L12
P4 Ni 5.71 12 0.013 164 5.2 0.33 1.43 0.23 17.1% 17.6 L3
P5 Ni + R2 11.24 18 0.013 184 9.3 0.93 2.41 0.38 4.05% 12.1 L4+C1 +
L5 + C2 +
P6 N2 0.82 6 0.013 138 1.9 0.05 0.60 1 0.09 41.9% 14.9 L7
P7 Ri 13.34 24 0.013 219 16.0 2.22 3.81 0.58 0.57% 6.0 L8 + L9 +
L10
P8 Ri 13.34 24 0.013 128 6.8 0.73 2.24 0.33 11.5% 18.3 Lii
Determination ot Q1UiJ tor I-'ipe F (uontluenre Analysis)
DMA Tc
min
I
in/hr
Q
cfs
QT
cfs
Ni 2.55 7.11 5.71 10.39
R2 3.02 7.11 5.53 11.24
Q 11.24 cfs
Tc 3.02 mm
I-IvdriiIirs (kiiItinns (ChnnI'i
Channel Upstream
DMAs
Qioo
cfs
H
ft
W
ft
n h
ft
Fb
ft
Ax
ft2
P
ft
R
ft
S
ft/ft
v
ft/s
Di Part of Ni 0.06 0.5 2.0 0.015 0.06 0.44 0.03 0.68 0.04 3.8% 2.2
D2 Part ofN2 1 0.47 1 0.5 2.0 0.015 0.18 0.32 0.15 1.27 0.12 1.9% 3.2
flfermintinn nf (1flfl ('.nntrihiitinri tn (hnnis
DMA Tc
min
I
in/hr
A
sf
Q
cfs
Part ofNl <5min. 7.11 401 0.06
Part of N2 <5 min. 7.11 3220 0.47
App B.2 Hydraulics Page 1 of 1
Royal Jet Remodel
Hydrology Calculations
P6 2.7 in
P24 5.0 in
P6/P24 0.54
P6,adj 2.7
rue-ueveiopmeru i<auon2' ivietrioa ,alculaucls
DMA A A L S a,i C Li Ti Ii Ai Qi
sf ac ft ft/ft ft min in/hr sf cfs
[1 46173 1.06 160 0.040 0.97 0.88 65 1.97 7.11 4895 0.71
DMA hi zi Axi Pi Ri n vi Qi L2 v2 TI
ft ft2 ft ft ft/s I cfs ft I ft/s mm
El 0.08 50 0.29 7.7 0.04 0.014 2.4 0.71 95 4.7 0.44
DMA Tc I Q z2L z2R n2 h2 Ax2 v2
min in/hr cfs ft ft2 ft/s
El 5 7.11 6.67 50 0,125 0.015 0.24 1.41 1 4.7
Piinnn Anon PtInn2I Nliathnri ('2Ir'IIItirnc (fnr Pvtlmi dirc ci7inrl\ . ................................
DMA A A L S a,i C Li Ti Ii Ai Qi
sf ac ft ft/ft ft min in/hr sf cfs
Ri 90785 2.08 192 0.020 1.00 0.90 70 2.39 7.11 2874 0.42
R2 37613 0.86 156 0.020 1.00 0.90 70 2.39 7.11 905 0.13
DMA hi zi Axi Pm Ri n vi Qi L2 v2 TI
ft ft2 ft ft ft/s cfs ft ft/s mm
Ri 0.07 50 0.24 7.0 0.03 0.013 1.7 0.42 122 4.6 0.65
R2 0.05 50 0.10 4.5 0.02 0.013 1.3 0.13 86 3.3 0.63
DMA Tc I Q z2L z2R n2 h2 Ax2 v2
min in/hr cfs ft ft2 ft/s
Ri 5 7.11 13.34 50 0.125 1 0.014 0.34 2.92 4.6
R2 5 1 7.11 5.53 50 50 1 0.013 0.18 1.68 3.3
in I
I
I
I
I
App B.1 Hydrology Page 1 of 2
i-'osi-ueveiopmenii<auonai ivietnoa Laicuiations
DMA A
SI
A
ac
L
ft
S
ft/ft
ai C Li
ft
Ti
min
Ii
in/hr
Ai
SI
01
cfs
Ni 38960 0.894 192 0.035 0.996 0.898 60 1.86 711 2874 0.42
N2 5586 0.128 156 0.010 0.988 0.893 60 1 2.88 7.11 905 0.13
DMA hi
ft
zi Axi
ft2
P1
ft
Ri
ft
n vi
ft/s
01
cfs
L2
ft
v2
ft/s
It
mm
Ni 0.06 50 0.21 6.5 0.03 0.014 2.0 0.42 132 4.3 0.69
N2 0.05 50 0.14 5.3 0.03 0.014 0.9 0.13 96 1.7 1.23
DMA Tc
min
I
in/hr
0
cfs
z2L z2R n2 h2
ft
Ax2
ft2
v2
ft/s
Ni 5 7.11 5.71 50 0.125 0.015 0.23 1.32 4.3
N2 5 7,11 0.82 50 0.125 0.015 0.14 0.49 1.7
DMA Tc
min
I
in/hr
0
cfs
QT
cfs
Ni 5 7.11 5.71 6.53
N2 5 7.11 0.82 6.53
0 6.53 cfs
Tc 5.00 mm
0100 Comparison
Condition A
ac
Q Tc
min cfs
Pie-Development 5.00 5.00 6.67
Post-Development 5.00 5.00 6.53
Change 0.00 0.00 -0. 14
% Difference 0.0% 0.0% J_-2.1%
I
I
I
I
I
I
I
App B.i Hydrology Page 2 of 2 1
I
I
LI
LI
fl
H
I
I
I
I
I
H
Pnct-flp,pInnmpnt Modified Rational Method Calculations
Royal Jet Remodel
Hydraulics Calculations
Hydraulics Calculations (Pipe)
Pipe Upstream
DMAs
0100
cfs
d
in
n a
deg
h
in
Ax
ft2
P
ft
R
ft
S
ft/ft
v
ft/s
Grading Plan
Tags
P1 R2 5.53 18 0.013 189 9.7 0.98 2.48 0.39 0.85% 5.7 Li
P2 R2 5.53 18 0.013 145 6.3 0.55 1.90 0.29 4.05% 10.1 L2
P3 Ni 5.71 12 0.013 181 6.0 0.40 1.58 0.25 10% 14.4 L12
P4 Ni 5.71 12 0.013 164 5.2 0.33 1.43 0.23 17.1% 17.6 L3
P5 Ni + R2 11.24 18 0.013 184 9.3 0.93 2.41 0.38 4.05% 12.1 L4 + Ci + L5
P6 N2 0.82 6 0.013 182 3.1 0.10 0.80 0.13 7.9% 8.1 L6
P7 Ni + N2 + R2 12.06 24 0.013 208 14.9 2.05 3.63 1 0.56 0.57% 1 5.9 1 L7
P8 Ri 1 13.34 1 24 1 0.013 219 1 16.0 1 2.22 3.81 0.58 0.57% 1 6.0 1 L8 + L9 + L10
P9 Ri 1 13.34 1 24 1 0.013 128 1 6.8 1 0.73 2.24
1
0.33 11.5% 1 18.3 1 L 1
flfrminit rn nf fli fill fnr Pino P (('nnfli wonrin Anhui
DMA Tc
min
I
in/hr
0
cfs
01
cfs
Ni 5 7.11 5.71 11.24
R2 5 7.11 5.53 11.24
Q 11.24 cfs
Tc 5 mm
Hydraulics Calculations (Channel)
Determinaton ot U10U tor IIre 11 ((ontluence Analysis
DMA Tc
min
I
in/hr
Q
cfs
01
cfs
N1+R2 5 7.11 11.24 12.06
N2 5 7.11 0.82 12.06
Q 12.06 cfs
Tc 5 mm
Channel Upstream -QIOO
DMAs cfs
H
ft
W
ft
n h
ft
Fb
ft
Ax
ft2
P
ft
R
ft
S
ft/ft
v
ft/s
Di Part of Ni 0.06 0.5 2.0 0.015 0.06 0.44 0.03 0.68 0.04 3.8% 2.2
D2 Part ofN2 0.47 0.5 1 2.0 1 0.015 0.18 1 0.32 1 0.15 1.27 0.12 1 1.9% 1 3.2
Determination of 0100 Contributinq to Channels
DMA Tc
min
I
in/hr
A
sf
Q
cfs
Part of Ni <5min. 7.11 401 0.06
Part ofN2 <5min. 1 7.11 1 3220 0.47
App B.2 Hydraulics Page 1 of 1