HomeMy WebLinkAboutCT 02-01; PACIFIC VIEW CONDOMINIUMS; HYDROLOGY AND HYDRAULIC STUDY PACIFIC VIEW; 2003-09-22HYDROLOGY AND HYDRAULIC STUDY FOR
PACIFIC VIEW CONDOMINIUMS
LOTS 1,2 & 3 OF MAP 1747
CORNER OF JUNIPER AVENUE & CARLSBAD BOULEVARD
CITY OF CARLSBAD, CALIFORNIA
ENGINEER OF WORK
EXCEL ENGINEERING
440 State Place
Escondido, CA 92029
(760) 745-8118
SEPTEMBER 22, 2003
HYDROLOGY STUDY
OBJECTIVE
The objective ofthis study is to determine the amount of runoff that the project site is generating right now & compare
it to the runoff that the fmished project generates.
CALCULATIONS
Steps taken to get the Q(IOO) for each basin are as follows:
1) Determine Basin Areas
Obtain runoff coefficients per Appendix IX-B lV-A-9 Rev. 5/81 and Appendix IX of the Manual. For this site use 2)
3)
weighted C for the development and C=0.45 for the pre-development assuming soil group D.
Calculate time of concentration per the Appendix X-A IV-A-10 Rev. 5/81 ofthe San Diego Hydrology Manual.
4)
T; =(ii.9iV//)°^*' r, = (1.8(1.1-C)VZ)/5"^
For natural basins For urban basins
Calculate intensities per Appendix XI lV-A-14 Rev 1/85 ofthe Manual
5) Solve for the Q using Q=CIA
Note: for all related maps and tables for this study see Appendix.
PRE-DEVELOPMENT (100 YEAR STORM)
BASIN (A) ARE A SOIL LENGTH Difference In Elevation Tc Tc*10 1 C Q = CM
(Acres) Type (Feet) (High) (Low) H (Mins) (Mins) (In/Hr) cfs
1 3.430 D 540 48 44 4 6.56 16.56 4.26 0.45 6.58
2 1.150 D 330 47.9 45.6 2.3 5.00 15.00 3.24 0.7 2.61
TOTAL 4.580 TOTAL 9.f9
The pre-development hydrology basin map is presented here in the Appendix. This generates 9.19 cfs of
runoff as calculated for a 1 OO-year storm using the method as outlined in the San Diego County Hydrology
Manual. However runoff (Q(l 00)=2.6 Icfs) from Basin 2 is offsite, thus the only runoff on the site 6.58 cfs.
Existing topography indicates that this runoffs flows to the east comer of the site including the offsite
runoff thru the 6" pvc pipe, however, the flow form this 6" pvc will be disconnected and removed (please
see attached letter). Thus, only the flow from the site will be considered.
POST-DEVELOPMENT (100 YEAR STORM)
Calculate Post-development Q(100) Time of Concentration
BASIN (A)A REA SOIL LENGTH Difference In Elevation Slope rc rc / c Q(100)
(Acres) Type (Feet) (High) (Low) H (Mins) (Use) (in) (Cfs)
1 0.080 D 50 46.5 46.25 0.25 0.50 6.41 6.00 5.86 0.7 0.33
2 0.670 D 157 48 46.5 1.5 0.96 9.16 9.00 4.51 0.7 2.11
3 1.200 D 260 49.7 47.1 2.6 1.00 11.61 12.00 3.74 0.7 3.15
4 0.100 D 130 48.6 47.1 1.5 1.15 7.83 8.00 4.86 0.7 0.34
5 1.150 D 330 47.9 45.6 2.3 0.70 14.75 15.00 3.24 0.7 2.61
6 0.067 D 140 49.2 47.8 1.4 1.00 8.52 9.00 4.51 0.7 0.21
7 0.250 D 140 49.3 47.9 1.4 1.00 8.52 9.00 4.51 0.7 0.79
8 0.340 D 138 49.5 48 1.5 1.09 8.23 9.00 4.51 0.7 1.07
9 0.370 D 138 49.2 47.8 1.4 1.01 8.42 9.00 4.51 0.7 1.17
10 0.240 D 135 49.5 48.1 1.4 1.04 8.26 8.00 4.86 0.7 0.82
11 0.150 D 60 49.2 47.8 1.4 2.33 4.20 6.00 5.86 0.7 0.61
TOTAL 4.617 TOTAL 13.212
The post-development hydrology basin map is presented here in the Appendix. Per the Manual a minimum
6 minutes is to be used on urban basins.
From the above computation, it is shown that basin 3 (offsite basin of 1.15 ac) have a runoff of 2.61 cfs
thus leaving only 10.602 cfs as the final runoff for the developed site. This gives a 4.022 cfs of runoff
increase.
Calculate Q's to treat using the State Water Resource Control Board Requirements
Per the Califomia Regional Water Quality Control Board, San Diego Region, order no. 2001-01 pages 18
& 19, in order to get the requires flow to be treated, we can either use :
i. The maximum flow rate of runoff produced from a rainfall intensity of 0.2 inch of rainfall per hour; or
ii. The maximum flow rate of runoff produced by the 85th percentile hourly rainfall intensity, as
determined from the local historical rainfall record, multiplied by a factor of two; or
iii. The maximum flow rate of runoff, as determined from the local historical rainfall record, that achieves
approximately the same reduction in pollutant loads and flows as achieved by mitigation ofthe 85th
percentile hourly rainfall intensity multiplied by a factor of two.
For this project we are going to use the maximum flow rate of runoff produced from a rainfall intensity of
0.2 inch of rainfall per hour.
BASIN (A)AREA SOIL LENGTH Difference In Elevation Slope rc fc 1 C Q(100)
(Acres) Type (Feet) (High) (Low) H (Mins) (Use) (in) (Cfs)
1 0.080 D 50 46.5 46.25 0.25 0.50 6.41 6.00 0.20 0.7 0.01
2 0.670 D 157 48 46.5 1.5 0.96 9.16 9.00 0.20 0.7 0.09
3 1.200 D 260 49.7 47.1 2.6 1.00 11.61 12.00 0.20 0.7 0.17
4 0.100 D 130 48.6 47.1 1.5 1.15 7.83 8.00 0.20 0.7 0.01
5 1.150 D 330 47.9 45.6 2.3 0.70 14.75 15.00 0.20 0.7 0.16
6 0.067 D 140 49.2 47.8 1.4 1.00 8.52 9.00 0.20 0.7 0.01
7 0.250 D 140 49.3 47.9 1.4 1.00 8.52 9.00 0.20 0.7 0.04
8 0.340 D 138 49.5 48 1.5 1.09 8.23 9.00 0.20 0.7 0.05
9 0.370 D 138 49.2 47.8 1.4 1.01 8.42 9.00 0.20 0.7 0.05
10 0.240 D 135 49.5 48.1 1.4 1.04 8.26 8.00 0.20 0.7 0.03
11 0.150 D 60 49.2 47.8 1.4 2.33 4.20 6.00 0.20 0.7 0.02
TOTAL 4.617 TOTAL 0.646
HYDRAULIC STUDY
OBJECTIVE
The purpose of this study is to show that the proposed storm drainage facilities are adequate to handle the
flows that the project will generate.
CALCULATIONS
The following will be analyzed and designed to adequately handle the developed Q(IOO).
1. Analyze the capacity of a 2'x2' brooks box
2. Calculate effective treated mnoff of propose fossil filters for catch basins if they exceed the 85*
percentile storm event.
3. Calculate the capacity of all storm drain system (pipes and catch basins) that will drain the site.
1. Analyze the capacity of a 2'x2' brooks box
Determine the flow capacity in cubic feet per second for a 24"X24"Brooks Box grate type inlet using the
following orifice equation of grate inlets in a sump.
Q{cap) = 4.nAy'
This equation is derived from the standard grate inlet formula from Seelye's Data Book for Civil Engineers
book page 18-27. c=0.6. Also, consider a 2/3 factor to account clogging of the grates.
Qicap) = cA^J(2gy)
Given: 2'x2' box We have:
A= 4.000 sf Q{cap) = 9.13 cfs
y = 0.5 ft
Where A = Area of opening in square feet.
y = Depth of flow at inlet or head of sump in fee
Recall from the hydrology study that the maximum mnoff that goes to a brooks box is only 3.15 cfs (basin
3). Therefore the propose boxes are adequate to handle the Q(IOO) runoffs.
2. Calculate effective treated mnoff of propose fossil fiael filter if they exceed the 85* percentile storm
event.
From the attached Filtration Capacity Chart a 24" x 24" Brooks Box could treat up 100 gpm of flow. From
our table computation the greatest flow is 0.17 cfs (basin #3) which is equivalent to about 76.3 gpm.
Therefore, this project meets the Califomia Regional Water Quality Control Board requirements.
3. Calculate the capacity of all storm drain system (pipes and catch basins that will drain the site
Please see Appendix for the attached flow computation from HydroFlow from Intelli-solve Software for
pipe flow comtutations.
Based on this flows we can conclude that the pipe systems proposed for the project are adequate to handle
all flows.
CONCLUSION
From our summary tabulation we have for our pre development Q(IOO) total for the site (basin 1) is 6.56
cfs and for our post development Q(IOO) total for the site is 10.602 cfs. There is a increase in flow of 4.042
cfs.
Although there is a substantial increase on the mnoff flow, these flows directly to the existing storm drain
system on the street, thus this proposed project will not adversely impact the existing downsfream
properties.
APPENDIX
RU.VOFF COEFFICIENTS (R.ATIONAL .METHOD)
L.'O.D USE Coefficient, r
Soi 1 Group 1)
Undeveluoed
iiesiden- iai:
A
. 50
B
. 55
C
.40
.Rural . 55 .-10
Singie Family . 40 • -5 . .50 . 55
.Multi-Units • * .^5 . 30 .60
Mobile Homes [2) .45 .50 . 55
Commercial (2)
80-0 impervious
. 70 . 75 .30 . •. 3
Industrial (2)
90-i Impervious
.30 .35 .90 . .'3
OTES:
^1) Obtain soil group
and Flood Control.
from .maps on file with the Depar tment of Sanit at -.o:!
(23 IVhere actual conditions deviate significantly from the tabulated
imperviousness values of 30?o or 90%, the values given for coefficient
C, may be revised by multiplying 80?, or 90-; by the ratio of actuai
imperviousness to the tabulated imperviousness. However, in no case-
shall the final coefficient be less than 0.50. For e.Kamole: ConslCe:
commercial property on D soil group.
.Actual imperviousness = 50-^
Tabulated imperviousness = SO".
Revised C .X 0.35 = 0.35
.\P"EXD::
COUNTY OF SAN DIEGO
DEPARTMENT OF SAfilTATION S-
FLOOD CONiaOL
33*
30'
15
U.S. DEPARTMEN'
1 OO-YEAR 24-IIOl)R PRECIPITATION
"2fl-^IS0PLUVIALS 0? 100 -VEAR 24-llOUn
PRECIPITATIOH IM EflTIIS OF AN ItJCH
4 «>r
r OF CO.MMERCE
fATlOHAL OCVA\iC AHO AT iosl'HCKIC AUMtKISiTtlATION
'o»*«l"<>CV. HATrO.-^AI, WeATIIKR SE»VIC« ;CJAI, »TU01t» I»KA.VCI1, O^HCK Of tt
W -1
.10 117* 10' II'
FLOOO CO.'ITflOL
•20^ ISOPLUVIALS OF tOO-YEAR 6'HOUR
PRECiPiTATlOn 1^ lEilTllS OF m ILICII
33*
U.S. DEPARTMEN f OF COMMERCE
KATIOMAt, OCEANIC A?«0 AT5 OSPHCMtC AOMWUTHATIOM
iOttS BRANCH. OrriCE OF It
30'.
jriTrrmrtrhrn-TTrrn irmmrnmrntr-. r T";:I^'I trvtl'in I f lin,
! Equation; I - 7.44 D ''^^^
o
I • Intensity (In./Hr.)
« 6 Hr, Precipitation (In.)
D « Duration (Min.)
•X3
n n
5.? %
5,5 rf*
15 20
Minutes
30 40 50 1 2 3
Hours
4 5 5
Directions for Application:
1) From precipitation mps detennine 6 hr. and
24 hr. amounts for the selected frequency.
These maps are printed In the County Hydrolony
Manual {10, 50 and 100 yr. maps included in th
Design and Procedure Manual).
2) Adjust 6 hr. precipitation (If necessary) so
that it Is within the range of 45% to 65S of
the 24 hr. precipitation. (Kot i^rpllcable
to Desert)
3) Plat 5 hr. precipitation on the right side
of the chart.
4) Draw a line through the point parallel to the
plotted Hnes.
5) This line is the Intensity-duration curve for
the location being analyzed.
Application Form:
0) Selected Frequency too yr.
1) " ^"^ ^24' * % • ^*
2) Adjusted *Pg«
3) t^ * mfn.
4) I • In/hr.
24
In.
•Not Applicable to Desert Region
APPENDIX XI
IV-A-14
Revised l/SS
&- x|c>p€ in %
XL
S/op^ - / O '/o
Ca<:/'/'/c/e/7/ a/ /c'urc//. C-.SO
SAN DiEGO COUNTY
Q£p;, = T,vr,v4y QF SPECIAL DISTRICT SERVICES
DESIGN MANUAL ^_
UR3AN AREAS OVERLAND TIME
OF FLOW CURVES
SAN DiEGO COUNTY
Q£p;, = T,vr,v4y QF SPECIAL DISTRICT SERVICES
DESIGN MANUAL ^_
APPENDIX X-C APPENDIX X-C
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NOTE
||FOR N.\TUR.AL WATERSHEDS
11 AOO TEN MINUTES TO I
COMPUTED TIME OF CON- I
^CENTRATION- ^1
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SAN DIEGO COUNTY
DEPARTMENT OF SPECIAL DISTRICT
DESIGN MANUAL
APPROVED 'i-/-^'
SERVICES
NOMOGRAPH FOR DETERMINATfON
OF TIME OF CONCENTRATION (Tc)
FC« NATURAL WATERSHEDS
DATE APPENDIX X-A
JV-A-10 Rev. 5/6l
NGSOGJE EAEBtNT RECOBOtD a2-23INB0a(9SI.BIGE3 0F DEEDS
ARE:A=P.080 AQX isriNG PCC
POST DEVELOPMENT CONDITiON BASIN 4
AREA=0.10 AC
Q,<100)=0.34 CFS
o o CM I CO CM
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0)
CO
c
9 ui _i
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0)
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Q.
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LU
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Hydraflow Summary Report Page 1
Line
No.
Line ID Flow
rate
(cfs)
5.81
5.81
3.70
0.55
0.21
Line
size
(in)
12 c
12 C
12 c
8 C
8 c
Line
length
(ft)
11.5
25.0
80.0
41.0
44.0
Invert
EL Dn
(ft)
39.28
40.89
41.15
42.00
42.50
Invert
EL Up
(ft)
39.30
41.15
42.00
42.50
43.00
Line
slope
(%)
0.174
1.040
1.062
1.220
1.136
HGL
down
(ft)
40.28*
41.89*
43.19*
44.21*
44.33*
HGL
up
(ft)
40.59*
42.56*
44.06*
44.30*
44.34*
Minor
loss
(ft)
0.64
0.64
0.16
0.03
0.01
Dns
line
No.
End
1
2
3
4
Project File: LINE-1 .stm l-D-F File: SAMPLE.IDF Total No. Lines: 5 Run Date: 09-23-2003
NOTES: c = circular; e = elliptical: b = box; Return period = 100 Yrs.; * Indicates surcharge condition.
at (0 o.
Ui c o
ts
Q.
E o
O
S 5
O
3
CO
X
o
co
>.
X Minor loss (ft) 0.64 0.64 0.16 0.03 0.01 JL coeff (K) 0.75 0.75 0.45 0.85 1.00 1 D9-23-2003 Enrgy loss c 0.306 0.666 0.864 0.085 0.013 D9-23-2003 Che S **- Cp" 2.662 2.662 1.080 0.207 0.030 1 Date: i u ?
CM <o CO
CM CO
CO
CJ) r^ p OEO Rur u cj cj d o EGL elev (ft) 41.44 43.41 44.40 44.34 44.35 Vel head (ft) 0.85 0.85 0.35 0.04 0.01 nes: 5 E
S! Vel (ft/s) 7.40 7.40 4.71 1.58 0.60 ber of III Upstn Area (sqft) 0.79 0.79 0.79 0.35 0.35 otal nurr JC
*— 1.00 1.00 1.00 0.67 0.67 h-Dep 1.00 1.00 1.00 0.67 0.67 HGL elev (ft) 40.59 42.56 44.06 44.30 44.34 Invert elev (ft) 39.30 41.15 42.00 42.50 43.00 Len 11.5 25.0 80.0 41.0 44.0 M g 2.663 2.663 1.080 0.207 0.030 DF EGL elev (ft) 41.13 42.74 43.54 44.25 44.34 SAMPLE.I Vel head fft) 0.85 0.85 0.35 0.04 0.01 FFile: : (ft/s) o
Tt
o
Tt
CO iq o
CO l-D-E
n
> (ft/s) N: Tt d iwnstrei Area (sqft) 0.79 0.79 0.79 0.35 0.35 w Q Depth (•') 1.00 1.00* 1.00 0.67 0.67 HGL elev (ft) 40.28 41.89 43.19 44.21 44.33 Invert elev (ft) 39.28 40.89 41.15 42.00 42.50 stm O (CTS) 5.81 5.81 3.70 0.55 0.21 LINE-1.; Size —. c CM CM CM r— CO 00 CtFile: 1 Line r-CM CO Tt in Proje E
U) U) CO
a
TD
« O
O
"O o
E
tn
a. o •o
CO
CM
d
c o
I
ffl
ffl
S
as
•(B
(0 Lil
5
z
storm Sewer Profile Proj. file: LINE-1 .stm
Elev. (ft)
56.0
52.0
48.0
44.0
40.0
36.0
Line: 1
Size: 12 (In)
Line: 2
"Size: 12 (in)"
25 50
Line: 4
-Size: 8 (in)-
Line: 5
Size: 8 (in)-
75 100 125 150 175 200 225
Reach (ft)
3e.
REtiOINMENpED J>IP# fiEVtStON
EWSTWOaXSIE EASaiENr RECOBOED 6-22-23 IN BOOK 961. WGE SCF DEEDS
63«4 Lourda T«rr»ee
SanDiego. CA92120-3011
May 22. 2003
Mason family trust
550 w. "c" St. #1770
San Diego, Ca. 92101
Dear Mason family trust,
My name is James Zathas, the owner of the three vacant lots
adjacent to the north of your-property located at 3770 Carlsbad
blvd. in Carlsbad.
1 am in the process of starting grading to build six condominium
units but before I get the permit a"-problem has to be corrected.
The problem is a six inch steel pipe coUecting surface water
in front of your garage, going under fhe garage and draining into my
property. I have been advised that whoever put'the pipe draining
into my property constitutes an illegal act and therefore I am
requesting as a good neighbor to remove said pipe so that I proceed
with the grading within a month from now.
Should you like to discuss the issue further or have any questions
or need assistance to remove the pipe plisase call me at 619-719-8585
or write to me at my above address.
Your cooperation and speetiy s-olution to the abovesaid problem will
be very much appreciated
Sincerely
James Zathas
Z2 39W(d NHOr 99££03Z 90=61 E003/GI/60
Law Office of Dan Konncrch
Dan Konncrth, Arcorncy Ac Law
572 Crejtwood Drive
OceuMldc, CA 92054
(760) 529-0703
June 27,2003
RE: APN #204-251 -04; APN «04-251-05;
Pennission lo enter property
and consent to installation of stopper
on water pipe
Dear Mrs Beckhani:
I represent Mr. Zathas in the above-entitled inatter. Both Mike Collimore and yourself were very
helpful in resolving this simple issue over the weekend. Mr. Zathas is very concerned about his
inability to get the permits he needs very soon. We also desire not to create any impediments or
delays to the escrow in any way. Consequently', I strongly believe the solution found to this very
simple problem is a good one. Allowing Mr. Zathas access to the property and allowing him to
cover the pipe with an extremely inexpensive stopper is a cheap and logical solution to this
problem for all the parties involved.
With the pipe stopped, the City of Carlsbad will likely approve the permit he needs because, as
they will see it, there is no possibility that water would pass through it, The sellers will be
unaffected, The buyers will be able to tear out the old pipes and redo them when they choose to
improve the property at absolutely no additional expense to them.
I am asking that both parties sign a release allowing Mr. Zathas to enter the property and install a
pipe stopper that costs an estimated $4.00 from a home-supply store. After I receive the
signatures from both the buyer and the sellers, I will forward both documents to escrow. I foresee
no problems and delays whatsoever with escrow closure provided we receive the documents as
soon as possible. The installation could take as linle as a few minutes. Please fmd attached an
agreement to be signed by both parties in escrow. Although I foresee no problems, should you
have any questions please call me at (760) 529-0703 or on my cell phone at (760) 473-8515.
Thankfully,
Dan Konnerth, Esq.
CC: Mike Collimore, Ranch and Sea Realty
2963 Carlsbad Boulevard
Carlsbad, CA. 92008
CC: James Zathas
Zathas I. I
£0 39Vd NHOr 99£e03Z 90:61 £002/61/60
ei/:e'20aa i5:S' ibisi-wi'ati EMSM W>WERTH ESQ. "AGE B:
I hcTT-y wniwryrc aiwi <KHi»eftV to the following •otivity and altcrstionto the property
loceted « ^770 CnrtOtaA Blvd.. in Cgi»^>ad CA «n<l lesaJly described «s APN ^5 204-
251-Maud 204-251-05:
ly I'o allow Mr. Z«thai ud hii wcr/er(s). If iny, full righta of iafrtM UMJ «gr«M onto
rl'-i ftfecva aeswuUid prcpetr) itr the pun>ose of uiatallini • "stoppe;:^ on a water pipe;
2) Connsr* to tlif tafltaltttlon of a imall "itoppar" dtvica oo tkt water pipa which
Arx'xi: on'o tbe a^j^ccnt property ownad by Mr. Zathai.
' iij '}.'••'. ;}y;cutot/ex«cutrix ofthe Muon Family Tniii and duly authonted to consent to
these activities which i/fect my property.
(njMicinjr.TiXifvUtriK or £u*cifiiT.i ptsr^-,^•
'j«--de;r' M»*)n F»RiiK Tntft')
NAM- DATED
(E.M»;i.r.<ji^ei.uciN cr •nit.'TOTi.wi p-trior
cnc'-i "Miunic. F«fnMy Tr;»t")
f0 39Wd IvjHor 99££03Z. 90:61 £003/61/60