HomeMy WebLinkAboutCDP 02-28; KIKO RESIDENCE; DRAINAGE STUDY; 2003-02-24,.,
DRAINAGE STUDY
FOR
KIKO RESIDENCE
CARLSBAD -CALIFORNIA
February 24, 2003
PREPARED FOR: Fred & Jessica Kiko ·
PREPARED BY: Trevor Promnitz
TAIT
Consulting, Inc.
717 Pier View Way
Oceanside, CA 92054
Phone 760 433-1166
ASSESSOR'S PARCEL NUMBER: 203-140-10
HYDROLOGY STUDY -TESSICINI
TABLE OF CONTENTS:
I. INTRODUCTION
-IL DISCUSSION & CALCULATION
III. CONCLUSION
IV. VICINITY MAP
V. HYDROLOGICAL SOIL GROUP MAP
VI. PREVIOUS DRAINAGE AREAS
VII. RECENTLY GRADED DRAINAGE AREAS
VIII. REFERENCES
2
Introduction
The site is located on the western side of Ocean Street in Carlsbad, fronting onto the
Pacific Ocean.
The site will be divided into 3 drainage areas for analysis.
This report was prepared to determine the storm water discharge from the site.
Discussion & Calculation
1) The existing and proposed situations in Area A are very similar.
2) Area-B; C & D flows to the west, and discharges onto a sandy percolation basin on the
site.
3) Area E; F & G also flow to the west and discharge onto the same sandy percolation
basin on the site. ' ·
The drainage pattern, and impervious areas of the proposed development is similar to the
existing situation.
The existing and proposed situations in Area A are very similar.
Area B; C & D -impervi01,1s area increases from 0.038 Ac existing, to 0.05 Ac proposed
Area E; F & G -impervious area increases· from 0.028 Ac existing, to 0.04 Ac proposed.
The flow for the proposed situation, in the last two areas above, will be slightly greater
than the existing situation, but this will be negated as the discharge flows onto a sandy
percolation basin on the western side of the property.
The increase in discharge will merely take :fractionally longer to percolate into the sand.
(See calculations)
The following apalysis was performed in conjunction with the San Diego County
Hydrology Manual (SDCHM). Unless otherwise indicated all calculation worksheets are
from the appendices of the SDCHM.
The following calculations are referenced from the Section IV of the SDCHM.
Appendix X-C was used to determine the time of concentration
This Tc will be used in all calculations, as the length, and grade of each basin is similar.
Tc = 5 minutes minimum.
3
-----------------------------------------•
-
Runoff coefficient to be determined to calculate the discharge for each individual basin.
Soil group A, (Ml C soil has a percolation rate = 6.3 to 20 in./hr.)
Impervious areas C = 0.95 (concrete)
Pervious areas C = 0.20 (sand)
Using the time of concentration, the rainfall intensity was calculated using Appendix XI
from the SDCHM (see Calculations).
The calculated intensity for the site is as follows:
Intensity = 6.6 in/hr
· The rational method (Q=CIA) is used to calculate the flow generated for each respective
basin.
Proposed situation
Basin A
BasinB
BasinC
BasfuD
BasinE
Basin F
BasinG.
C=0.95
C=0.95
C=0.95
C=0.20
C=0.95
C=0.95
C=0.20
I= 6.6in/hr
I= 6.6in/hr
I= 6.6in/hr
I= 6.6in/hr
I= 6.6in/hr
I= 6.6in/hr
I := 6.6in/hr
A=0.08 Ac
A=0.01 Ac
A=0.02Ac
A=0:02Ac
TOTAL
A=0.01 Ac
A=0.02Ac
A= 0.01 Ac
TOTAL
Q = 0.50 cfs
Q = 0.06.cfs
Q = 0.12 cfs
Q = 0.02 cfs
Q = 0.20 cfs
Q = 0:06 cfs
Q= 0.12cfs
Q = 0.01 cfs
Q = 0.19 cfs
We used Manning's Fomula to determine the capacity of a 4" dia pipe at a gradient of
2.5%, and have determined that 0.4 cfs can be conveyed.
The flattest gradient on this pipe run is 4.5%, therefore a 4" dia pipe will be adequate.
Area drains are to be installed in the planter areas, which drains from one planter to the
.next, stepping down vertically, and will then discharge onto the sandy percolation basin.
We will use the combined discharge from the above areas, 0.20cfs-and 0.19cfs, to
determine the approach flow approach flow of0.39 cfs.
(The percola{ion rates given for this soil type, varies from 6.3 to 20 in/hr.)
Usmg the lowest percolation rate of 6.3 in/hr, we will calculate the time required for the
approach flow to percolate into the sand.
4
Volume cf = Oa x Tc(sec) x 2.7
2
= 0.39 X 300 X 2.7
2
= 158 cf
Area of the percolation basin= 1132 sf
158 = 0.13' deep (1.5 inches)
1132
0.13 = 0.02 x 60 = 1.24 minutes
6.3 in/hr
We are assuming that the percolation basin (Area D & G) Will overflow during the 100 yr
ston:n, the water spreads out & percolates into the sand.
We have determined that the flow will infiltrate the soil in approximately 11/4 minutes.
Conclusion
In conclusion, we have indicated that the volume of storm water being discharged ontq
Ocean Street from the site in the proposed situation, is ~qual to the discharge from the
existing situation.
We have indicated that the implementation of the proposed development,
will not significantly change the drainage patterns on the site.
The impervious area on the western side ofthe development is larger than in the existing
situation, the slight increase in discharge will merely take :fractionally longer to percolate
intothe soil.
The storm water will percolate into the sand at a faster rate than it can accumulate.
5
: · ...
. . · .,
. . . . '
CITY OF OCEANSIDE 78 .
PACIFIC ·
O.CEAN
CITY OF. VISTA
. NOT TO SCALE
CITY OF ENCINITAS
VICINITY MAP ·
....................... •· .. .. ................ ..
0
0
~'
~
0 z
0
0
Location & Soil Hydrologic Group Map
..... -------~----------------~~~---I
KIKO RESIDENCE
0 CE AN STREET
111
A
(0.08 Ac)
8
{0.01Ac) t
F E
(0.02Ac) (0.01Ac)
. . \__1:
/ I D
/ . (0.02Acr -~·111111--------__;;CIII /"
1"=20" ~ PU 8 LI f~ 0~~~~20~~~4o· ~· -DRAINAGE AREA EXHIBIT
0 L: \Kiko\DWG\EXHIBITS\KIKO-HA-SHT01.dwg _ 02/14/2003 03: 09: 07 PM PS'I"
TABLE 11.--INTERPRETATIONS FOR LAND MANAGEMENT--Continued·
Map
symbo
LfE
LpB
LpC
LpC2
LpD2
LpE2
LrE
LrE2
LrG
LsE
LsF
Lu· ·
LvF3
. MnA
Mn.B
MoA
MpA2
MrG
MvA
MvC
MvD
MxA
OhC
OhE
OhF
OkC
OkE
PeA Pee
PeC2
PeD2
PfA
PfC
Py
Soil
Las Flores,-Urban land complex, 9 to 30 percent slopes:· ·
Las Flores---------------·----------------------------
Urban land--------------------------------------------
Las Posas fine sandy loam, 2 to·5· percent slopes----------
Las Posas fine sandy loam, 5 to 9 percent slopes----------
Las Posas -~ine sandy -loam, 5 to 9 percent slopes,
eroded.-
Las Posas fine sandy loam, 9 to ~5 percent slopes,
eroded.
Las Posas fine sandy loam, 15 to 30 percent slopes,
eroded.
Las Posas stony fine sandy loam, 9 to 30 percent
slopes. · ·
Las Posas· stony fine sandy loam, 9 to 30 percent
slopes, eroded.
Las Posas stony fine sandy loam, 30 to 65 percent
slopes. _.
Linne clay loam, 9 to 30 percent slopes---------------~--
Linne clay loam, 30 to 50 pe~cent slopes-----------------
Loamy alluvial land-------------------------~------------Loamy alluvial land-Huerhuero complex, 9 to 50 percent
slopes, severely eroded: , Loamy alluvial land---,--------,----------·_., __________ _ Huerhuei'o-------· _________________________ ;. __________ _
ade land----· -.----------------------· --------. -----· ---
arina loam coarse sand 2 to 9 · ercent slo ·es----------
arina oamy coarse an· , b . p·ercen s opes----.----:-
ecca coarse sandy loam, Oto 2 percent slopes---~-------
ecca coarse sandy lpam, 2 to 5 percent sJopes-------7-:.-
ecca sandy loam, saline, Oto 2 percent slopes---------~
ecca fin_e sandy loam, 0 to· 2 percent slopes, ero.ded-----
etamorphic rock land-----------------~------------------
ottsville loamy coarse sand, 0 to 2 percent·s1opes------
ottsville loamy coarse sand, 2 to 9 percent slopes------:
ottsv'ille loamy coarse sand, 9 to 15 percent slopes-----
ottsville loamy coarse sand, wet, 0 to 2 percent
slopes.
livenhain cobbly foam, 2 to 9 :percent slopes-:----------,--.--
Olivenhain cobbly l~am, ~ to 30 percent slopes-----------
Olivenhain cobbly loam, 30 to 50 percent slopes----------
livenhain-Urban land complex, 2 to 9 percent slopes:
Oli venhain-----------------·-------· ----· ------------_
Urban land-----------.-------------------------------
livenhain-Urban 'land complex, 9 to 30 percent slopes:
Oliverihain------------------------------------------.
-Urban land---------------· ----------------------. ----
Placentia sandy-loam, 0 to 2 percent slopes-----~----~---Placent.ia sandy· loam, 2 to 9 percent slopes-_; ___________ _
Placentia sandy loam, 5 to 9 percent slopes, eroded-:.----
Pl-acentia sandy loam, 9 to 15 pe:r;-cent slopes, eroded-----
Placentia sandy loam, thick surface, 0 to .2 percent
sli;>pes. .
Placentia ~andy loam, thick surface, 2 to 9 percent
slopes.
Pla.yas------. · ----. -------------------. ------------------
See footnotes at ~nd of table.
36
Hydro-
logic
group
D.
D
D
'D
D
D
D
D.
D.
D
C
C
.B
D
D
D
A
13
B
B
B
D
A
A
A
D
D
D
D
-D
D
D
D
-D
D
D
D
D
D
D
Erodibility
Moderate 2----
Moderate 2----
Moderate 2----
Moderate 2----
Moderate 1---
Moderate 1---
Moderate 1---·
Severe 1-----
Moderate 2---
Severe 1-----
Severe 16---..'.
Severe 1-----
Severe 1-----
Severe 2--..:--
evere
Severe 16
Severe 16
Severe 16
Severe 16
Severe 1-·----·
Severe 2-----
Severe 2-----Severe 2-----
Severe 2-----
Severe 16----
Severe 16----
Severe 1--..:· __
Severe 9-----Severe 9-----Severe 9-----Severe 9-----
Severe 16----
Severe 16----
Moderate 2
Limitations for
conve~sion
from brush tc;,
grass
Slight.
.Slight.
Slight.
Slig~t.
Slight.
Moderate.
Moderate.
Moderate.
Moderate.
Moderate.·
Slight,
Severe.
Severe.
Severe.
Slight. 4/
Slight. 4/
Slight. 4/
Slight. !/
Slight.
Slight.
Moderate;
Slight.
Sl~ght.
Slight.
Slight.
Slight.
.Slight.
l ,,
lNTENSITY-DU,Vffiv .. _DESIGN CHART
Directions ·for Appli-cation:
1) From.precipitD.t.ion r:,aps detennine 6 hr. ·and
24-hr. amounts ror the s·e1 ected frequency.
These maps · are .pri nte~ in the County Hydro 1 ogy·
Manua 1 (1 O, 5!} nnd 100 yr. maps included in· th
Design and Procedure Manual). . ·
··2) Ad}ust 6 hr. precipitation ·(if necessary) so ·
that it is within the range of 45% .to.65% of
the 24 hr. precipitation. (-Hot applicable
to Desert) .
Plot 6 hr._prec1p1tation on the rio~t-side ·
of the char~. ·
Draw a 11 ne through the point para 11 el ·to the
· plotted 1 ines. · . . . . .
+++++-HH-Hl+H--1-+1--1,:~.w~uuU-1 · · ·· · 1,tt-r-t-t-·, ...... -.+H++-H 2) Adjuste~ *P 6= 2 .. 5 in.
. . .. . . 3) t = .:g min
III-ILIIIUIIL • . •• C ---------•
....... · ......... ·._ .. : · sm,1-1--:1-H-+:~ ... _¾-;'"H+1·--1-1-1-1-1+U-1:i 4) l = b.to in/hr . .(Ca\cu.\a:ted;
1-1--t~-H-H+H-4-4-1-1-1 I I , , I I I I I 1111111111111:H-J..IIHHl+l+.I--l+H+t+l't H · *Not Applicable to Desert Region
I • • •
_,_, ··• _, _ 1--1--1--J-1 .........
l FFf-l±ERt RHTTHnlm11Ji ... ,-
10 15 20
Minutes
30 40 so· 1
n,, .. -:.+-t nn.
'll llllllll-f-1-1-1--1--.:J-l--l-l-l+l-l-•·1
1-1-J.-H-l-++-t-H--l+I-I
2
-Hours
3 4 5 6
·\(rko · .
.•.
APPENDIX XI
IV-A-14
Revi .,.,.,t 1 /or-.
.,
I
. . . . ~ . ~ .... ,. ,,, ........ ····· . · .. II ...
. F~-~i'
S"IJIJ(}
,Id(}(}
3t)(}(J
·21fl)tJ
/IJd(} gm, .
SdO ...
7()1)
. GIJIJ ·,
/I)
' . .5 s~ ., .. ,~ 4
. IIDl.lrS Mi11ur~s
·4---240
//}t)
5/)'
Si)
·?I)
IIJtJ . '-~~
°3tJtJ -~ 3 IS SAO ., I . &tJ
Ii
· .. , ·.
21Jt). . .. " ..
. . . '-· .. ',,~. ' . . /.
l·
as
.JtJ NOTE _, ~...,......-----~ . 1FOR NATURAL WATERSHEDS
ZIJ I ADD TEN" .MINUTES TOj~
-~~~;;~._TIME OF CON-
-~--.· : . . . . =-==:-...z::=w~-=-~
. /() .
5
SAN ·DI EGO COUNT.Y
DEPARTMENT OF. SPECIAL ·-DISTRI-CT SERVICES . . . .
. . · ,oES 1-GN 'MANUAL
APPROVED ~3, /I. ~~ .. . . .
L
2()/JIJ
/8()0
/~(}I)
/~/J()
/.21JiJ
/Ot)t:J.
9/JtJ
80()
7'/}t)
GIJtJ ..
300.
StJ
--...
-NOMOGRAPH FOR DETERM'tNATfON
OF TIME OF CONCENTRATION ·(Tc)
. ..~OR-NATURAL WATERSHEDS ·
.· DATE . ./2../J /4 9 APPENDIX X-A
lT ~ 1 n n.... c-,1,
,:j
i -· r. ...
Table3-1
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use I Runoff Coefficient "C"
~ ~ . S~il Type
NRCS Elements County ~lements %IMPER. A B C D
Undisturbed N'.~tural Terrain. Permanept Open Space · . O* 0.25 0.30 -~~~--..
Residen,tia.},. 1.0 pU/A oi less :10 0:32 Low · I 027 0.36 0.41 ....
Low Residerftial, 2.0 DU/A.or"°Iess. 20. 0.34 -0.38. · 0.42 0.4fj
Low R~sidentjal, 2.9 DU/ A or less 25 0.38 0.41. 0.45 0:49.
Medium Density R~idential Residential, 4.3 DU/A·or less· 30 0.41 0.45 0.48 · 0.52 . .
Medium Density Residential Residential, 7.3 DU/A or less . 40 0.48 0.51 0.54 0.57
MecJium Density Residen~a.l Residential, 10.9 DU( A or less 45 0.52 0.54 0.57 0.60:
Medium Density Residential Residenti@l, 14.5 DU/A or'less . 50 0.55 0.58 0.60 0.63 . . . High Density Residential Residential, 24.0 DU/A or less. 65 0.66 · 0.67 · 0.69 0.71 . ·,
High Density Residenti·a1 Residential, 43_.0.DU/A or less · 80 0.76 Q.77 0.78 0.79
Commercial/Industrial Neighborhood Commercial 80 0.76 · ·0.77. 0;78 ·0.19
Comm~rcial/Industrial · General Commercial 85 0.80 0.80 0.81 0.82
Commerci~dustrial Office Professional/Commercial 90 0.83 0.84 .o.84 0.85 __
Commercial/Industrial Limited Industrial "9,0· 0.83· 0.84 0.84 o:ss
Commercial/Industrial General Industrial· ·95 ... o.9s·· ·o.95 0.95 0.95
*~ values associated with 0%Jmpervious m~y 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 rc~iri undisturbed in perpetuity. Justification must be given that the ai:ea.will remain natural
forever (e.g., the area is located in Cleveland National Forest). ·
IDU/ A = dwelling· units per acre
NRCS • National Resources Conservation Service
1'
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Prc·p•i·d br . I I
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'.' ·cwtrrY OF SAN' DIEGO
DEPARTMENT OF. SANITATION & . . . . . . . : . r , . . . . . . •
-· :100-Y,EAR 6~HOUR·· PRECI_.P·i.TATIO-N · . FLOOD COttrROL
....
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U.S. DEP~RTMEN r OF.COMMERQE.
· -NATIONAL OCEANIC-AND AT. OSPIIERJC AD~INISTRATION . . .
SPECIAL STUDIES.DRANCH."OFF'JCB OF II l>ROLOOY, NATiONAL lrEATHER SERVJCt . -I . I ' -30.'---I . . .-·· t" -1· • ,I . I I I
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