HomeMy WebLinkAboutCDP 2016-0005; KLOVANISH RESIDENCE; DRAINAGE STUDY; 2017-10-12RECORD COPY
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Initial Date
COFFEY ENGINEERING, INC. -
CPP20U,-cO05
I. Drainage Study
Kiovanish Residence
I Adams Street
Carlsbad, CA. 92008
I
I RECE WED
OCT 1:82017
I Prepared For: LAND DEVELOPMENT
Steve Kiovanish & Crystal Hollins ENGI NEERING
I and
The City of Carlsbad
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ESS/
INo. C076074
Cl
))7))
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October 12, 2017
9666 BUSINESSPARK AVENUE, SUITE 210 SAN DIEGO, CA 92131 PHONE: (858)831-0111 FAx: (858)831-0179
Table of Contents
Project Description 3
Drainage Patterns ..............................................................................................................................3
Purpose and Scope of Report ............................................................................................................ 3
Method of Calculations ..................................................................................................................... 4
Results and Conclusions: ..................................................................................................................5
Declaration of Responsible Charge ............................................................... ..................................... 6
Appendix A - Reference Drawings & Maps
Klovanish Residence - Grading & Drainage Plan
Drainage Map A. 1 - Existing On-site Conditions
Drainage Map B. 1 - Proposed On-Site Conditions
Appendix B - Drainage Design Manual References
Table 2 - Runoff Coefficients
Intensity-Duration-Frequency Curves
Nomograph for the Determination of Time of Concentration or Travel Time for Natural
Watersheds
Appendix C - Reference Tables & Figures (County of San Diego Hydrology Manual)
Soil Hydrology Groups
Table 3-1 - Runoff Coefficients
Figure 3-1— Intensity-Duration Design Chart
Table 3-2 - Maximum Overland Flow Length and Initial Time of Concentration
Figure 3-3 - Overland Time of Flow Nomograph
Figure 3-4 - Nomograph for the Determination of Time of Concentration or Travel
Time for Natural Watersheds
100-year, 6-hour Isopluvial map
100-year, 24-hour Isopluvial map
Project Description
The 18,614 ft2 lot is located on the 4000 block of Adams Street. The site is currently vacant with
no previous development. Proposed are is the construction of a single family residence, 2 above
ground wood decks, a pool/spa, and driveway. The proposed home will be on a raised foundation.
The driveway will be conventional PCC paving. Grading will consist of cutting into the existing
with a 2:1 slope at the rear of the lot to create a flat area for the raised foundation, cutting into
existing grade to create the driveway, and cutting into the existing slope along the property
frontage for required street improvements (road widening). Very little fill will be done on the site.
Drainage Patterns
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The site slopes consistently from the rear of the property to the front. There are no existing storm
drainage facilities within the site. The site does receive run-on from the entirety of the 2 adjacent
properties to the northeast. Runoff entering the site as well as from the site itself sheet flows to the
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fronting street (Adams Street). Once at the street runoff travels northwesterly along the site of the
street (no existing curb & gutter) and enters a grated inlet approximately 300' from the site. This
inlet is connected to a storm drain that discharges at the opposite side of Adams St. and then 300'
down a slope to the Agua Hedionda Lagoon. The existing drainage conditions are depicted on
I Drainage Map A. 1 included in Appendix A.
The project proposes to intercept storm water run-on at the rear property line with an earthen swale
and landscape drains and will route it around the site to the east in an independent drainage system
and will discharge it to the street via a standard D-25 curb outlet. Offsite runon will not be
comingled with onsite runoff at any point.
Onsite runoff from around the house will be addressed with small diameter landscape drains, all of
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which are directed to a 236 ft2 biofiltration area which is intended to provide treatment control
only. Runoff from the driveway will be intercepted by a 6" channel drain that will also discharge
stormwater to the single onsite bioretention area. The biofiltration area will have a control structure
I with a perforated subdrain as well as a grated inlet for overflow. The control structure is connected
to an underground cistern with a small diameter orifice for flow control. The system ultimately
discharges to Adams Street via a second D-25 curb outlet. The proposed drainage conditions are
I depicted on Drainage Map B.1 included in Appendix A.
Purpose and Scope of Report
This report will evaluate the pre-construction hydrologic conditions as well as the post-construction
I conditions to quantify increases or decreases in runoff from the project and for the design of
drainage system components for a 100-yr design storm for flood control purposes.
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4. Method of Calculations
The Rational Method, as defined by the County of San Diego Hydrology Manual (2003), will be
used to calculate storm water flow rates. Where noted, the following calculations were used to
determine flow properties:
Rainfall Characteristics
Q = C * I * A, where
Q = Flow rate (ft3/sec)
C = Runoff coefficient
I = Rainfall intensity (in/hr)
A = Area (acres)
I = 7.44 * P6 * D °45, where
I = Rainfall intensity (in/hr)
P6 = Adjusted 6-hour precipitation (inches)
D = Storm duration (mm), equal to T for time-of-concentration storms
Tc = Ti+Tt+Tp (time-of-concentration), where
Ti=Over land initial time.
Tt=Travel time on natural watersheds.
Tp=Travel time on drainage structures (pipes, brow ditch, gutter etc.)
Ti= 1.8(1.1-C) D°50 /( s°'33 ) (Overland initial time of concentration formula),where
D= Watercourse Distance (feet)(see table 3-2 for the max. overland flow length)
s = Slope (%)
C= Runoff Coefficient
Ti=Initial time of concentration (mm.)
Tt = (11. 9*L3 / An) °385 (formula for travel time for natural watersheds), where
= Time of Concentration or Travel time (hours)
L = Length of watercourse (miles)
AH = Change in effective slope height (ft)
Pipe and Open Channel Flow Characteristics
V = 1/n * R213 * S"2 (from Manning), where
V = Average cross-sectional velocity (ft/sec)
n = Manning roughness coefficient
R = Hydraulic radius (ft)
S = Slope of water surface (ft height/ft length)
ri
p/y + V2 /2g + z1 + hL = ply + V2 /2g + z2 (from Bernoulli), where
p = pressure (lbs/fl2)
y = density (lbs/fl)
V = velocity (ft/sec)
g = gravity (ft/sec/see)
z = height of fluid (ft)
hL = head loss (ft)
5. Results and Conclusions:
Left unmitigated, the proposed project would result in an increase in runoff from pre-construction
levels due to the construction of impervious areas on the previously vacant lot. Un-mitigated runoff
flowing to the street would increase from 1.88 cfs to 2.61 cfs. Of these quantities the offsite
properties contribute 1.18 cfs.
To mitigate this increase an underground detention system has been designed to attenuate the flows
from the developed site to pre-construction rates. The detention will consist of the EcorainTM
system which is a modular system. For the purposes of this project, the Eco-rain TM system will
cover a 280 ft2 footprint and have a 5 ft. depth. To reduce runoff discharging from the site to pre-
development rates a low flow orifice of 0.35" will be installed at the base of the system. To account
for possible overflows, a 12" diameter corrugated PVC pipe will be installed near the top of the
storage system. Both outflow pipes shall be connected to an outlet structure that ultimately
discharges to the fronting street (Adams Street) through a San Diego Regional Standard D-25 curb
outlet. The detention system has been calculated to reduce the total runoff from the site from
1.88 cfs to 1.43 cfs. Full runoff calculations are included in Appendix B.
The reduction in total runoff from the developed site (as compared to the existing site) leads us to
conclude that the proposed project will not adversely affect the subject property nor properties
downstream of the project.
6. Declaration of Responsible Charge
I hereby declare that I am the Civil Engineer of work for this project, that I have exercised
responsible charge over the design of the project as defined in section 6703 of the business and
professions code, and that the design is consistent with current design.
I understand that the check of project drawings and specifications by the City of Carlsbad is
confined to a review only and does not relieve me, as Engineer of Work, of my responsibilities for
project design.
Daniel Valdez 1/ Date
RCE 76074
Exp63018
Bibliography
County of San Diego. 2005. Drainage Design Manual
http: / /www.sdcouniv.ca.gov/dpw/floodcontrol/drainage.html
County of San Diego. 2003. Hydrology Manual
http: / /www. sdcountv.ca.gov/dpw/floodcontro1/hvdro1ogvmanua1.htm
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Appendix A - Referenced Plans & Drainage Maps
250'
-
__________
SC
10 BIKE -
LANE TRAMI LANE
06A4DE IL'I 2%
1-2 RIl
706
704
702 5 P.C.C. PAVING 'CONFIRM PAVEMENT SECTION WITH
W//4 REBAR 0 GEOTECHNICAL ENGINEER PRIOR TO
'cc I8 O.C.' \ CONSTIAUCIION
16' WIDE
DRIVEWAY 98
96
94 NATIVE MATERIAL COMPACTED
PRE-SOAKED CoMRACIIN
To REL
TO 2% OVER_ IRA 6W?S II BASE'
92 OPTIMUM CONTENT TO A
DEPTH OF 18'
PROPOSED LOCAIION rJ8J I
/ OF ELECTRICAL PROPOSED -
'.. CONNECTION 5 MAX RET. 78x18 BROOKS INLET '.. ..
WALL PER SORSO (OR SIM.) INTERCEPT -_ N
- BRW .
DWG. C-6 (E) LINE FROM UPHILL
- 3 PROPERTY BRW 720.2 RIM= 12390- IE=I22.40BRW 120.0 TF 119.2
I
__.;••
- 8 LA WALL 8 PvV PIPE / PAPCL 3
-IHICH -
0 IX MIN. _-J7 PM 792
PQC - -J' IF 7208 N BRW 7220 B
AUTO COU 7 71W 1270 /KS POOL DECK KS POOL r
a
ASk 'I
TERS CB
BR -121-.8 L EARTHEN
PROPOSED \ ,/
W 12O k ___ /i=io I N i RlM72O3 -
120 VALE PER (P) 6 CO
BRW 7797 IE 11852 n0 N CB - - --
DETAIL 0 RIM=1265
IF 718.7 [ --
------- RIM 7 - -
-, IE-I2l.37
\ -
-
o . -.. RETAINING WALL
I 177205 ffOU N
PfRSDRSO C-6 Upp
RIM-120 I GARAGE OF
720 7 IIO8ThRFEN 1 PIPE FOR (2) UPSTREAM WALL O \ AN
120.5 8 ASS STORM DRAIN
I BY
EP Ili
-- i;- - - OF5 j1 , .. IE 1l7.2I3 VARIES. MAINTAIN 72 MIN.
.. • . Lop / - -' COVER. NOT CONNECTED 10
v g MA RIM- 720.7
ON-SEX DRAINAGE SYSTEM
---------- .,IEII8.45 / / D(. FENCE
------- N I 550 PROP HOUSE TO REMAIN
RAISED FF 121.0 CB
.•f / -s s CRAWL SPACE PAD-1 78.5, RIM-120.1 1 PROP HOUSE
RAISED FF=121.0 j CRAWL SPACEPAD-718
EX FENCE
IN
TO EUN 0SC4EE
----- -. -. ' ------- -
RIM= 120.7 ------------------------------ KSING FO -''-
POR11ON OP 1-01 _\S4DE TO REMAIN -.--.--_.------ ° 770 0Rj0 54f! I
BY SEPA447F
-MAP ND. 2i52 Rfzc '5202 6CENB_ - j•BLOCK 0 '%
DO)2LbcE ER KS. RESIDENCE
.. •-• ----------------- -'--- /' -
cTJPJcAToP .
L40DSCE
cOMPLJANCO P5R I I8HM4X
ooc:2o-i6-4752o1
- .. .. IRAININC / L 4
RC / 13 3
EQLIIPROOM
PM 1
109.3
TRENCH DRAIN --- ---- .
FF 110.0
IF 105. I ,CO -
I
, RIM-IO9
GRATE EL=101.6-
-___ • ••- -8 -.
228 ET' BIOFILTNA1ION / N
- - - - -.-AREA PER DETAILS 8 PVC BYPASS STORM DRAIN
2 UPSTREAM
- BRW 102~74Z - _\_______ - - CK -----/
-5"
PROPERT/Dh4IMGE.SLOP---------
',VARIES. MAINTAIN 12" MIN. IF 10 1. 70
COVER. NOT CONNECTED TO
W44. PER SDRSD- ECORAIN STOWAGE~~_\. V-9.4 FPS
100.52 0' BELOW GROUND
BRW 100,70
'AII'SEE DETB)
R8'-°126 PUBLIC STREET
3 CA-. MYE1AS 40 .cT\\ - _-
- - IE..-9793 & UIILJTY EASEMENT S LF '<NI
I - i SIMPLEX 5)MP \ \ '33. JE-I0I.0O PER 2077 0007 . 102 ,--- N -
PUMP. 1p~
-------
00W 970 ORONAR ..CEOUTFLOW H R
_
ES DETAIL B -PE 28'43'20" - -
a=±94.q --
--
PERMISSION FOR OEX 930 - -
PROPOSED LX:
-- ERASING TO BE OBTAINED BY IF - -- I WATER SCE
DEVELOPER_
2 i - PER S TO
L BIRi'L4NE-GUTTER PER
5.
-
/ SIRE T ' CURB OU7LET PER
- - - -Z -- --7 - - - - -
0 I'PS4
0-1.18 CFS
WCUT UNE TRENCHING PER MA
MIN.
-- 72
EAIING
W-2(WATER
NAS-)b SHOWN ON 149-8
PAMN
I2O 106
130 104
SCALE: 17=10 728 K 128 702 fX C1N - - - - 726 726 101
724 724
124 724 98
722 722 (P)CJAIOE-
N -
K r°'-T CR4 722 722 96
20 94
118 - 778
7t_1
(P) RET. IL 778 118 92
116 779 74C - $4 - __ 90Q - ' " - -70 0 0 10 0 70 20 -- 30 - DETAIL 'E'- TYPICAL DRIVEWAY SECTION
NOT TO SCALE
A%S1O FUS'ITITLE 91SYPADG 11CC 1m.fl,c SCCTha2/15/17
-'1171820810 - NW!
K2W -g
"Aill"llow- "AA
7,7
1 I I I 21jfI8.1.J9.MP_7sRiEDI.J. • :
'
t •P!.aiI 'IIr j
Ur , 111841!
I •
'J 1 ø20Ø202)ZBO, (ZØ "8ItT
W.jVi:•Jr.!VhYi.J ) A • 1t4A'
NO SCALE
or
BIOFILTRATIONAREA A. VEGETATED COVER
(N/N. 4 GRASS)
DETAIL 'C'- BIOFILTRATION DIMENSIONS
SCALE: 1-70' DETAIL DEARTHENSWALE
NOT TO SCALE - -
DRAINAGE NOTES:
I ALL MAIN DRAIN LINES 5NOV18 TO BE 6 PV 0 IX MINIMUM SLOPE UNLESS 011401181Sf NOTED PER PLAN
2. I44RDSCAPE GRADES ID BE 2% MINIMUM 10 DRAINS AND AWAY FROM STRUCTURE
E SOFISCAPE GRADES TO BE 5% MINIMUM TO DRAINS (IX WHERE FLOW IS CONCENTRATED) AND SX MINIMUM AWAY FROM STRUCTURE
SOIL COVER ABOVE DRAIN ONES SHALL BE I2 MINIMUM UNLESS OTHERWISE NOTED.
NOIIFT CIVIL ENGINEER IF ANY NON-DRAINING SUMP CONDITIONS BECOME APPARENT DURING CONSTRUCTION.
AT ALL STORM WATER DISCHARGE LOCAI10NS. SUITABLE ENERGY DISSIPATERS ARE TO BE INSTALLED TO REDUCE THE DISCHARGE TO NON-ERODIBLE VELOCITIES.
NO AD07110144L RUN-OFF IS PROPOSED FOR THE DISCHARGE LOCATIONS.
B THE LAISIING WATER AND SEND? SERVICES WILL REMAiN.
"AS BUILT"
POST CONSTRUCTION BMP TABLE
TYPE SIZE OWNERSHIP RCE......._.__...._ EXT _________ DATE
BIOFILTRATTON 236 S.F. I<LO VANISH
(PRIVATE) REVIEWED BY
HYDROMOD 1,400 C.F. (PRIVATE)
- (DETENTION) - INSPECTDV DATE
SHEET CITY OF CARLSBAD SHEETS
2 ENGINEERING DEPARTMENT 6
GRADING PLANS FOR:
KLOVAN!SH RESIDENCE
4385 ADAMS STREET
TRADING PLAN CR201 7-0026
APPROVED: JASON S. GELDERT
CITY ENGINEER RCE 63912 EXPIRES 9/30/16 DATE
BIN BY F_ PROJECT 0. OVAWil INITIAL DATE INIDAL ~DATTql CHAD BY- 01L........_OF WORK REVISION DESCRIPTION RVWD BY- cP 2016-0005 503-9A
LEGEND
DESCRIPTION
PROPERTY LINE
EXISTING CONTOUR
BASIN LIMITS
DIRECTION OF FLOW
SYMBOL
N45°45'45"W ·Fr.-- ----
OMA 10--1x ,1
Impervious/
Developed Area Pervious
OMA {SF} Area (SF) Total {SF} Total (AC}
Y.1 -Offsite
Tributary Area 20,610 0.47
X.l 18,614 18,614 0.43
~ O .fO BO 120
SCALE: 1·=40'
Percent
C-Value* Impervious I /4 .--.," ' . . . ·. .f r'! " .. ,
I ,;~ -~-·L",/' / 'ii\11
0.38
o.2sl 0.00°/o
KLOVANISH RESIDENCE -DRAINAGE MAP A. 1 -EXISTING CONDITIONS
~ COFFEY ENG IN EERIN G, IN
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Impervious/
Developed Area Pervlous Biofiltratlon Pool/Water
OMA (SF) Area (SF) Area (SF) Feature (SF)
A.1 {Drains to
Biofiltration)
SMA 1 (Self
Miti_gating Area)
B.1 (De
Mini mus)
Total
Developed
7,2581 4!6801 2361
5,079
250
7,508 9,759 236
LEGEND
DESCRIPTION
PROPERTY LINE
EXISTING CONTOUR
PROPOSED CONTOUR
BASIN LIMITS
SYMBOL
N45 ° 45 '45 ''W ·Ff..-----
---90--------
6" PVC DRAIN LINE &
LANDSCAPE DRAINS
DIRECTION OF FLOW
BROOKS BOX (OR SIM)
W/GRATE
8/0FILTRA TION AREA
IMPERVIOUS AREA
PERVIOUS AREA
OMA 10--10.31
SITE CHARACTER/ST/CS
• HYDROLOGIC SOIL GROUP ........... B
• APPROX/MA TE DEPTH TO
..
~
l~a~iil -
GROUND WATER ........................ >6.5'
• CRITICAL COARSE SEDIMENT
YIELD AREAS ............................. NONE
..
4721
775
1,247
' --------'----~~ Percent V
Total (SF) Total (AC) Impervious
20 o l 20 40 60 ........... I I
S~LE1 1 "-26.' '-
I I "-
I I
12,6461 0.291 51.3go,1,~awr~ ..... (p:l~ I I I
5,854 0.13
250 0.01
18,750 0.43
-'-
-------I ' --,1· ' ~
-
'-
-
', . ,I
---.... ., 1-.:!....'"l"r"°' -----' "": " :8 ' ' ------
......... --------------
-' _]
I., u ----
" ...... -' --:z:.
----II -...._ -, II ' ~, ...... _ II
- - -·---- - \ 111
...... '-I
---. ---~
'
.......... ....._ ___ ---
-- -.... ---
...._ --
' '
---J'\t QI
B. 1, ~r"
----IC ~
: L __
L ___ '
'--
"-I
--
--r -~ -....._ ------/ ,-v
FROM IMP A:'2 '\ FROM AREA Y. 1
ow.x=1.22 cFs ADAMS STREET "-ow.x=1.1a c Fs
Vw.x=3. 44 FPS -Vw.x=3 40 FPS ----'\ -----.
TOTAL -MITIGA~TAL-UNMITIGATED ~ ----
Qw.x= 1.4.;J. ers QuAx=2.61 eFs -----~------>~· 11 FPS V11AX=4. 78 FPS ---
KL OVA NISH RESIDENCE -DRAINAGE MAP 8.1 -PROPOSED CONDITIONS
~ COFFEY ENGINEERING , INC.
Table A - Weighted Runoff Coefficients (C')
Impervious/
Developed Area Pervious Biofiltration Pool/Water Percent
DMA (SF) Area (SF) Area (SF) Feature (SF) Total (SF) Total (AC) CValue* Impervious
V.1 - Offsite
P' Tributary Area 20,610 0.47 0.38
--
rj X.1 18,614 18,614 0.43 0.25 0.00%
A.1 (Drains to
Biofiltration) 7,258 4,680 236 4721 12,646 0.29 0.64 57.39%
o' SMA 1 (Self
Mitigating Area) 5,079 775 5,854 0.13 0.21 0.00%
(p
13.1 (De Minimus) 250 1 250 0.011 0.951 100.00%
Total Developed 7,508 9,759 236 1,247 18,750 0.43 0.56 40.04%
*Impervious Areas C=0.95; Pervious Areas C=0.25; Pervious Payers C=0.40
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I Appendix B - Calculations/Evaluations
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Table B - Pre Construction Flow Characteristics
Natural Watercouse (per Fig. 3-4) Urban Overland (Sheet) Flow (per Fig. 3-3) Pipe/Channel Flow Summary 100-yr P6 = 2.50
Watercou Natural Urban (5 min minimum)
Element & rse Change in watercouse watercourse Maximum Initial Ttime of Overland Pipe Average Pipe travel Total time-of- Rainfall Basin
Dwelling distance, Elevation, H duration, D distance, Ti (ft) Overland Flow Watercourse Runoff Concentration Flow Time, Length, L velocity, V time, T concentration, T Runoff Coefficient, Intensity, I Area, A Q(cfs) = Q (cfs)
Flow ID (Basin) Unit/Acre L (ft) Elev. 2 (ft) (mm) LM) Length slope, s (%) Coefficient, C (per Fig. 3-2) Tt (mm) (ft) (fps) (mm) (mm) C (in/hr) (acres) C*l*A Mitigated
V.1 - Offsite
Tributary Area LDR-2 140 126 22 0.72 0.00 0.00 5.00 0.38 6.59 0.47 1.18
--
X.1 Natural 130 94 32 0.57 0.00 0.00 5.00 0.25 6.59 0.43 0.70 --
QTOTAL 1.88
Table C - Post Construction Flow Characteristics
Natural Watercouse (per Fig. 3-4) Urban Overland (Sheet) Flow (per Fig. 3-3) Pipe/Channel Flow Summary 100 -yr P6 = 2.50
Watercou Natural Urban (5 min minimum)
Element & rse Change in watercouse watercourse Maximum Initial Ttime of Overland Pipe Average Pipe travel Total time-of- Rainfall Basin
Dwelling distance, Elevation, H duration, D distance, Ti (ft) Overland Flow Watercourse Runoff Concentration Flow Time, Length, L velocity, V time, T concentration, T Runoff Coefficient, Intensity, I Area, A Q (cfs) = Q (cfs)
Flow ID (Basin) Unit/Acre L (ft) Elev. 2 (ft) (mm) (!5 LM) Length slope, s (%) Coefficient, C (per Fig. 3-2) Tt (mm) (ft) (fps) (mm) (mm) C (in/hr) (acres) C*l*A Mitigated
V.1 - Offsite
Tributary Area LDR-2 140 126 22 0.72 0.00 0.00 5.00 0.38 6.59 0.47 1.18 1.18
A.1 (Drains to LDR -2 0 0.00 30 100 5.00 0.64 0.00 2.65 216 3.0 1.20 5.00 0.64 6.59 0.29 1.22 0.043
SMA 1 (Self
Mitigating Area) LDR -2 50 98 22 0.22 0.00 0.00 5.00 0.21 6.59 0.13 0.18 0.18
B.1 (De Minimus) LDR - 2 20 290 4 0.15 0.00 0.00 5.00 0.95 6.59 0.01 0.03 0.03
QTOTAL 2.61 1.43
Drainage Component Evaluations
Pipe and Open Channel Flow Characteristics
Q=VA
Q=flow rate (ft3/sec)
V= Velocity (ft/sec)
A= Cross Sectional Area of Water in Pipe/Channel (ft2)
V = 1.49*1/n * R213 * 5112 (from Manning), where
V = Average cross-sectional velocity (ft/sec)
n = Manning roughness coefficient
R = Hydraulic radius (Area/Wetted Perimeter -ft)
S = Slope of water surface (ft height/ft length)
l"PYCPIN --_ Offllle lluft..On • 1"
Manning N
Diam eter (inches) l.Closed Conduit -PVC
8
Slope (FT /FT) Q(CFS)
0.01
Depth (feet) Depth/Diameter
0.46108
Velocity (ft/sec) Velocity Head (feet)
4.581435434
Wetted
Area (ft2) Perimeter (feet)
0.25756122
Page 1 of 7
0.011
1.180
69.16%
0.325924699
0.196703452
POC 1 (ECISTING FLOW ALONG EDGE OF PAVIMIIIII' Wlnlt
Manning N
Invert Width (feet) 22.Lined -Concrete (Poured)
0 0.014
Slope Q(CFS)
0.025 1.880
Left Side Slope (X to 1) Right Side Slope (X to 1)
1.5 so
Depth (feet) Top Width
0.15475 7.97
Velocity (ft/sec) Velocity Head (feet)
3.048549409 0.14431139
Wetted
Area (ft2) Perimeter (feet)
0.616685073 8.018256621
Hydraulic Radius
0.076910119
Page 2 of 7
I" Curb at ,OC 1 (U~:: _. Flow)
Manning N
Invert Width (feet) 22.Lined -Concrete (Poured)
0 0.014
Slope Q(CFS)
0.025 2.610
Left Side Slope (X to 1) Right Side Slope (X to 1)
0.333333333 10
Depth (feet) Top Width
0.32500 3.36
Velocity (ft/sec) Velocity Head (feet)
4.782500513 0.355160111
Wetted
Area (ft2) Perimeter (feet)
0.545739737 3.608824607
Hydraulic Radius
0.15122368
Page 3 of 7
&" Cun at ,OC 1 .. . --,1owt
Manning N
Invert Width (feet) 22.Lined -Concrete (Poured)
0 0.014
Slope Q (CFS)
0.025 1.430
Left Side Slope (X to 1) Right Side Slope (X to 1)
0.333333333 10
Depth (feet) Top Width
0.25934 2.68
Velocity (ft/sec) Velocity Head (feet)
4.115076287 0.262948026
Wetted
Area (ft2) Perimeter (feet)
0.347502671 2.879731917
Hydraulic Radius
0.120671882
Page 4 of7
oaUMtal*llln -. . Offsl1le Atie• Y.1)
Manning N
Invert Width (feet) 22.Lin ed -Concrete (Poured)
3 0.014
Slope Q(CFS)
0.02 1.180
Left Side Slope (X to 1) Right Side Slope (X to 1)
0.01 0.01
Depth (feet) Top Width
0.11552 3.00
Velocity (ft/sec) Velocity Head (feet)
3.403667664 0.179890583
Wetted
Area (ft2) Perimeter (feet)
0.346684611 3.231045664
Page S of 7
D-25 Undefttl'llln iw . ..:...:._ Oflllte ArAA.1 • MfflllATIDt
Manning N
Invert Width (feet) 22.Lined -Concrete (Poured)
3 0.014
Slope Q(CFS)
0.02 0.043
Left Side Slope (X to 1) Right Side Slope (X to 1)
0.01 0.01
Depth (feet) Top Width
0.01543 3.00
Ve locity (ft/sec) Velocity Head (feet)
0.929011314 0.013401584
Wetted
Area (ft2) Perimeter (feet)
0.046282915 3.030855233
Hydraulic Rad ius
0.015270579
Page 6 of 7
o..zsu.......,.:---Ol'fllle ArN A.1 • UNMR'IM1181
Manning N
Invert Width (feet) 22.Lined -Concrete (Poured)
3 0.014
Slope Q(CFS)
0.02 1.220
Left Side Slope (X to 1) Right Side Slope (X to 1)
0.01 0.01
Depth (feet) Top Width
0.11792 3.00
Velocity (ft/sec) Velocity Head (feet)
3.447281569 0.184530283
Wetted
Area (ft2) Perimeter (feet)
0.353902047 3.235853787
Hydraulic Radi us
0.109368986
Page 7 of 7
Integrated Management Practices Sizing Calculations
A.1 (Drains to Biofiltration}
Low Flow Threshold Soil Group Slope Rair, Guage
0.1Q2 D High Runoff (Clay Soils) Steep Ocean: 1de
Surface Area (ft2) Surface Area (AC) Surface Type Runoff Factor
Impervious Area 7,258.00 0.17 Concrete (1.01 1
Pervious Area 4,680.00 0.11 Landscape (0.1) 0.1
Pervious Pavers 0.00 0.00 Solid Unit Pavers o 0.2
Surface Area
IMP Type Area Factor Vl Factor V2 Factor Surface Area Required (ft2) Vl Required (ft3) V2 Required {ft3) Provided (ft2) Vl Provided (ft3) V2 Provided (ft3)
Cistern N/A 0.18 N/A 0.00 1,390.68 0.00 1,400.00
Orifice Sizing Calculations
(1) Q=Cd X A X (2gH)05 Orifice Discharge Equation
(2) A= [O. lQ2 x AoMA]/Cd x (2gH)°"5 Orifice Area Equation (for 0.1Q2 as lower limit threshold)
A.1 (Drains to Biofiltration)
I
I
I
Cd = 0.58
dimensionless
Rain Gage Soil Type
Oceanside D
Soil
Rain Gauge
Oceanside A
Oceanside A
Oceanside A
Oceanside B
Oceanside B
Oceanside B
Oceanside C
Oceanside C
Oceanside C
Oceanside 0
Oceanside D
Oceanside D
Oceanside A
Oceanside B
Oceanside C
Oceanside D
Oceanside Impervious
g = 32.2
ft/s2
H = 5.0000
ft
Cover Slope Q2 Sizing Factor OMA Area (ac)
Scrub Steep 0.244 0.29
Table 1-6. Unit Runoff Ratios
..------~ -... -,
Cover Slope Q2 Q10
(cfs/acre) (cfs/ac)
Scrub Low 0.035 0.32
Scrub Moderate 0.093 0.367
Scrub Steep 0.163 0.42
Scrub Low 0.08 0.365
Scrub Moderate 0.134 0.4
Scrub Steep 0.181 0.433 I
Scrub Low 0.146 0.411
Scrub Moderate 0.185 0.433
Scrub Steep 0.217 0.458
Scrub Low 0.175 0.434
Scrub Moderate 0.212 0.455
Scrub Steep 0.244 0.571
Urban Moderate 0.152 0.411
Urban Moderate 0.188 0.434
Urban Moderate 0.216 0.458
Urban Moderate 0.247 0.571
Moderate 0.557 0.949
Lower Limit of Q2
0.1
Orifice Area (in2) Orifice Dia. (in)
0.10 0.35
Storage System Drawdown Time For Basin:
System: Eco Rain A.1 (Drains to Biofiltration)
Orifice Dia. (ft) Orifice Dia. (in) Footprint (Ft2) Drawdown Time (hours)
0.03 0.35 280 17.350 <96 Hours -OKAY
Depth of Water L'i Time L'i Time in Sto rage
Chamber Q (ft3/sec) 6 Vol (ft3) (sec) L'ITime (min) (hours)
5.0000 0.043934423 0
4.9167 0.043566765 23.33 533.32 8.88 0.14
4.8333 0.043195977 23.33 537.86 8.96 0.14
4.7500 0.042821979 23.33 542.52 9.04 0.15
4.6667 0.042444685 23.33 547.30 9.12 0.15
4.5833 0.042064008 23.33 552.21 9.2 0.15
4.5000 0.041679854 23.33 557.25 9.28 0.15
4.4167 0.041292126 23.33 562.43 9.37 0.15
4.3333 0.040900722 23.33 567.77 9.46 0.15
4.2500 0.040505537 23.33 573.25 9.55 0.15
4.1667 0.040106458 23.33 578.90 9.64 0.16
4.0833 0.039703368 23.33 584.72 9.74 0.16
4.0000 0.039296143 23.33 590.72 9.84 0.16
3.9167 0.038884654 23.33 596.90 9.94 0.16
3.8333 0.038468763 23.33 603.29 10.05 0.16
3.7500 0.038048327 23.33 609.88 10.16 0.16
3.6667 0.037623192 23.33 616.70 10.27 0.17
3.5833 0.037193199 23.33 623.74 10.39 0 .17
3.5000 0.036758176 23.33 631.04 10.51 0.17
3.4167 0.036317942 23.33 638.60 10.64 0.17
3.3333 0.035872306 23.33 646.44 10.77 0.17
3.2500 0.035421065 23.33 654.57 10.9 0.18
3.1667 0.034963999 23.33 663.01 11.05 0.18
3.0833 0.03450088 23.33 671.80 11.19 0.18
3.0000 0.034031458 23.33 680.94 11.34 0.18
2.9167 0.03355547 23.33 690.46 11.5 0.19
2.8333 0.033072632 23.33 700.40 11.67 0.19
2.7500 0.03258264 23.33 710.78 11.84 0.19
2.6667 0.032085166 23.33 721.63 12.02 0.2
2.5833 0.031579857 23.33 733.00 ·12.21 0.2
2.5000 0.031066329 23.33 744.92 12.41 0.2
2.4167 0.030544168 23.33 757.44 12.62 0.21
2.3333 0.030012925 23.33 770.62 12.84 0.21
2.2500 0.029472107 23.33 784.51 13.07 0.21
2.1667 0.028921178 23.33 741.29 12.35 0.2
2.0833 0.028359548 23.33 814.70 13.57 0.22
DrawDown Cale Page 1
2.0000 0.027786569 23.33 831.16 13.85 0.23
1.9167 0.027201523 23.33 848.66 14.14 0.23
1.8333 0.026603614 23.33 867.32 14.45 0.24
1.7500 0.025991955 23.33 887.27 14.78 0.24
1.6667 0.025365551 23.33 908.66 15.14 0.25
1.5833 0.024723281 23.33 931.67 15.52 0.25
1.5000 0.024063875 23.33 956.53 15.94 0.26
1.4167 0.023385883 23.33 983.49 16.39 0.27
1.3333 0.022687639 23.33 1012.87 16.88 0.28
1.2500 0.021967212 23.33 1045.05 17.41 0.29
1.1667 0.021222343 23.33 1080.50 18 0.3
1.0833 0.020450361 23.33 1119.83 18.66 0.31
1.0000 0.019648071 23.33 1163.80 19.39 0.32
0.9167 0.018811596 23.33 1213.39 20.22 0.33
0.8333 0.017936153 23.33 1269.91 21.16 0.35
0.7500 0.017015729 23.33 1335.16 22.25 0.37
0.6667 0.016042583 23.33 1411.64 23.52 0.39
0.5833 0.015006462 23.33 1502.99 25.04 0.41
0.5000 0.013893285 23.33 1614.77 26.91 0.44
0.4167 0.012682776 23.33 1755.96 29.26 0.48
0.3333 0.011343819 23.33 1942.29 32.37 0.53
0.2500 0.009824036 23.33 2204.60 36.74 0.61
0.1667 0.008021292 23.33 2615.06 43.58 0.72
0.1000 0.006213266 18.67 2622.72 43.71 0.72
0.0900 0.005894421 2.80 462.51 7.7 0.12
0.0800 0.005557314 2.80 489.00 8.15 0.13
0.0700 0.005198391 2.80 520.65 8.67 0.14
0.0600 0.004812775 2.80 559.37 9.32 0.15
0.0500 0.004393442 2.80 608.28 10.13 0.16
0.0400 0.003929614 2.80 672.82 11.21 0.18
0.0300 0.003403146 2.80 763.69 12.72 0.21
0.0200 0.002778657 2.80 905.88 15.09 0.25
0.0100 0.001964807 2.80 1180.57 19.67 0.32
0.0000 0 2.80 2850.15 47.5 0.79
Total Vol. 1400.00 Total Hours 17.35
l*Omax
DrawDown Cale Page 2
Appendix C -Reference Tables & Figures (County of San
Diego Hydrology Manual)
10
"I'll" IItIIIIIIIIHIIIIIIIIHIIIIIIIllhIIIIIIIIIIIIIIIUIIIIIIIIIIIIIII
ilIi*;IlIhuII _ih.
San Diego County Hydrology Manual Section: 3
Date: June 2003 Page: 6 of 26
Table 3-1
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use I Runoff Coefficient "C"
Soil Type
NRCS Elements County Elements % IMPER. A B C D
Undisturbed Natural Terrain (Natural) Permanent Open Space 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. Corn) Neighborhood Commercial 80 0.76 0.77 0.78 0.79
Commercial/Industrial (G. Corn) General Commercial 85 0.80 0.80 0.81 0.82
Commercial/Industrial (O.P. Corn) 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 I.) 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 Section: 3
Date: June 2003 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 Tj values based on average C values for the Land Use Element are
also included. These values can be used in planning and design applications as described
below. Exceptions may be approved by the "Regulating Agency" when submitted with a
detailed study.
Table 3-2
MAXIMUM OVERLAND FLOW LENGTH (LM)
& INITIAL TIME OF CONCENTRATION (Ti)
Element* DU/
Acre
.5% 1% 2% 3% 5% 10%
LM T1 LM TiLM T1 LM Tj LM Tj LM T
Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9
LDR 1 1 50 12.21 70 11.5 1 85 10.01 100 9.51 100 8.01 100 6.4
LDR 2 50 11.3 70 10.5 1 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 1 50 9.2 1 65 8.4 80 7.4 1 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 1 95 4.3 1 100
HDR 43 50 5.3 1 65 4.7 1 75 4.0 1 85 3.8 95 3.4 100 2.7
N. Corn 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7
G. Corn 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4
O.P./Corn 50 4.2 60 3.7 70 3.1 80 2.9 1 90 2.6 100 2.2
Limited I. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100
General I. 50 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100.9
j.2
*See Table 3-1 for more detailed description
3-12
100 30
I-
C') W I- w W z
z 20
z - W - w L) z
W co Li..
io z
of w W > 0
EXAMPLE:
Given: Watercourse Distance (D) = 70 Feet
Slope (s)=1.3% 1.8 (1.1-c) V5 -
Runoff Coefficient (C) = 0.41 T
- Overland Flow Time (1) = 9.5 Minutes
SOURCE: Airport Drainage, Federal Aviation Administration, 1965
FIGURE
Rational Formula - Overland Time of Flow Nomograph
3m3
1
Wh 1F
For
mppm 0 dd
0a
S
Mon
• EQUATION
AE 1.9L3 O.385
Feet Tc
=) CAE
5000 Tc = Time of concentration (hours)
I = Watercourse Distance (miles)
4000 AE = Change in elevation along
effective slope line (See Figure 3-5) (feet)
3000 Tc
Hours Minutes
2000 4 240
3 180
1000
900
800 2 _______ 120
—100 100
90
500\\ 80
400 \ 70
1 60
300
50
200 40
I
\ Miles Feet 30
100 1,
4000 20
18
3000 16
50 0.5--14
40 2000 12
1800
1600 10 30 1400 ' 9
1200 8
20 1000 7 900
800 6
700
600
10 500 4
400
300
5
200
A L Ic
California Division of Highways (1941)and Kirpich (1940)
FIGURE
Nomograph for Determination of
Time of Concentration (Tc) or Travel Time (Tt) for Natural Watersheds 3_,4
• ~ !:: -
--t--+--+
32•45 t++ ~+
+-I hafil t + . •
Hll111: ~tH-1~~
~ I I ~~ t ~-~ ... --1:-,,.., .. ' ~ OTT t t 3 ~',"' , -T L., , JE k ~ · ,... • ' • -, ::.: fitL' r : M e v-1 ~t -;-• t ; -' " " ; ; : : : • -; ro t ,, , , t t • .. t t ~ t .. • ~ •
t:: f T +~$' 0 , ", •
· L .. LL . :: +-+ ~ ~ +. ~ . t:: ' H+H-:-: ':f f + ~ t t
.0. x·
----... . .... ++-..+. f' • • ~~ ~ -' ~tm..;: ~ ,-~
l-l-..-+ i.n~r .. +-;.. ~" +-+-..
~ ~ -~ ~
g
C. ~
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Hydrology Manual
• Soil Hydro/ogic Groups
Legend
Sotl Groups
D GroupA
-GroupB D Groupe
D GroupD
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Hydrology Manual
• Rainfall Isopluvials
100 Year Rainfall Event - 6 Boon
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