HomeMy WebLinkAboutSDP 98-15; KELLY RANCH VILLAGE F; DRAINAGE REPORT; 1998-11-01I
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DRAINAGE REPORT
FOR
KELLY RANCH VILLAGE 'F'
CARLSBAD, CALIFORNIA
NOVEMBER 1998
SDP 98-15
Prepared For:
HILLMAN PROPERTIES
2011 .Palomar Airport Road, Suite 206
Carlsbad, CA 92009
Prepared By:
PROJECT DESIGN CONSULTANTS
701 B Street, Suite 800
· San Diego, CA 92101
Document No. 1224.40
Dale R. Greenhalgh, PE RCE 43964
Registration Expires 6/30/01
Prepared By: SM
Checked By: MW
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Section
TABLE OF CONTENTS
File: 1224.40
November 1998
INTRODUCTION............................................................................................ 1
EXISTING CONDITIONS AND BACKGROUND........................................ 3
DEVELOPED CONDITIONS.......................................................................... 4
HYDROLOGY METHODOLOGY................................................................. 5
FLOOD ROUTIN'G CALCULATIONS............................................................ 13
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9
. · INLET DESIGN ................................. , ........... :................................................. 17
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REP/12244DR.DOC
OUTLET DESIGN ANALYSIS....................................................................... 19
SW ALE CAPACITY CALCULATIONS........................................................ 20
DETENTION BASIN CAPACITY.................................................................. 21
REFERENCES................................................................................................. 22
APPENDIX A-HYDROLOGY DESIGN,CHARTS
RunoffCo~fficients (Rationai Method) ................................................ A-1
Rainfall Intensity-Duration-Frequency Curves ................................. A-2.1
100-Year, 6-I:{our Precipitation Map .................................................... A-2.2
100-Year, 24-Hour Precipitation Map .................................................. A-2.3
Nomograph-Time of ConcentratiQn for Natural Watersheds ............. A-3.1
Urban Are~ Overland Time of Flow Curves ....................................... A-3.2
Ri.p-Rap Table .................... ~·································································· A-4
Nomogram -Capacity Curb Inlet at Sag .............................................. A-5
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Figure
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REP/IZ244DR.DOC
File: 1224.40
. November 1998
LIST OF FIGURES
Description
V ... M 1c1m'ty ap .....................• .-............................................................................... . 2
LIST OF TABLES
Description Page
Predevelopment Hydrology Calculations ......................................................... 9
Postdevelopment Hydrology Calculati.011$........................................................ 11
Flood Routing Calculations.............................................................................. 15
ATTACHMENT
Exhibit A D~age Area Map -DevelQped Conditions
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SECTIONl
INTRODUCTION
File: 1224.40
November 1998
This drainage report has been prepared to document the design and calculations for the storm
drain system associated with the Grading Plan for Kelly Ranch Village 'F'. The development is
located in the Kelly Ranch Master Planned Community in the Ci!Y of Carlsbad, southeast of
C~on Road and south of El Camino Real. It is approximately 4 miles east of Interstate Route 5
and is about 3 miles south of State Route 78. Please refer to the vicinity map on Page 2.
The objective of this drainage report is to determine pipe_ size and catch basin capacities under
the· developed conditions to carry a required frequency storm water volume in the development
area. ' .
The project is located within the City of Carlsbad limits and is subject to City standards. The
drainage sub basin layout and the ~tortn clrainage system are shown on Exhibit 'A' attached to this
report.
REP/12244DR.D<X; 1 .
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REP/l2244DR:DOC
File: 1224.40
EVANS POINT
CT 97-16
CANNON
Fi~ur~ 1. :Vicinity Map
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SECTION2
EXISTING CONDITIONS AND BACKGROUND
File: 1224.40
November 1998
This project lies east of the Agua Hedionda Lagoon and therefore any runoff from the site,
overland or underground, should be taken to a desilting basin and then outletted.
All runoff from this pr~ject will be deposited in an exist~g onsite desilting basin which was
constructed for Drawing No. 258-3A.
The existing desiltation basin was designed for a post development Qso of 9 .1 CFS from this
drainage basin. Refer to Detention ..... Desiltation Basin Report for CT 83-30.
The existing 100-year/6-hour peak flows are shown on the predevelopment hydrology calculation
tables so they can be compared with the postdevelopnient conditions.
. REP/12244DR.DOC J
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SECTION3
DEVELOPED· CONDITIONS
File: 1224.40
November 1998
The Kelly Ranch Village 'F' consists of one visitor center contained within 7.8 gross acres. The
' site is proposed to contain a visitor center, parking lots, and landscaping.
Drainage from the developed area will be conveyed via an underground storm drain pipe at the
south end of the project and outletted into an existing onsite detention basin that will then be
outletted to the Agua Hedionda Lagoon.
Drainage from :Basin Al (refer to Exhibit 'A') will be collected into one catch basin, which will
then outlet to the existing detention basin through an underground pipe.
The 100-year/6-hour storm situation will be analyzed to determine the storm drain pipe.
REP/12244DR.DOC 4
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SECTION4
HYDROLOGY METHODOLOGY
File: 1224.40
November 1998
This drainage syste111 has been designed in general conformance with the County of San Diego
Hydrology Manual. Drainage basins ate less than 0.5 square mile; therefore, the Rational and
Modified Rational Methods were utilized to calculate storm runoff. The underground storm drain
system is designed to convey the 100-year-frequency storm water. Pipes are sized for
nonpressurized flow. The underground systems outlet to detention basin via energy dissipators.
the hydro.logical analysis utilized to determine the runoff at each design point was the Rational
Method (Q = C x Ix 4.). The following pages describe the methods used to determine each
component of the Rational Method equation, in which
Q = Runoff'(CFS),
C = Runoff coefficient,
/,4. = Rainfall intensity (in/hr), and
A = Are~ (acres).
4.1 Determination of Runoff Coefficient
Runoff coefficients are dependent. on the proposed land use of the basin. Coefficients for this
project were obtained from the County of San Diego Design and Procedure Manual (see
Appendix A-1). Soil Group D has been assumed for this area. Based on these criteria, the
following runoff coefficients were used:
Natural Urtdisturbed Area = 0.45 .
'Paved Areas = 0.95.
For Basin A.I which has 111ore than one land use (natural undisturbed and paved),. a weighted
value of C will be used in calculations.
REP/12~44DR.DOC 5
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4.2 Determination of Intensity .
File: 1224.40
November 1998
Rainfall intensity (I) is based on the "Intensity-Duration-Frequency" curves in the County of San
Diego Drainage Design Manual (see Appendix A-2).
4.3 Time of Concentration
Time of concentration. is the time required for runoff to flow from the most remote part of the
watershed to the outlet point or design point under consideration. The time of concentration (Tc)
at any point within the drainage area is given by:
where
·T, = Inlet time and
T, = Travel time.
Inlet time is broken down into two cqmponents: overland time (T0) and gutter time (Tg):
therefore,
The following paragraphs further define the individual components of the time of concentration
and the methods used to quantify those components.
4~3.1 Overland Time (T 0)
Overland time is the period required for runoff to travel from the farthest edge of a drainage
basin to the street gutter. The method of determining overland time is dependent on the type of
watershed. For natural watersheds, overland time is determined using the Appendix A-3.1 (taken
from the San Diego County Design Manual).
REP/12244DR.DOC 6
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4.3.2 Gutter Time (Tg)
File: 1224.40
November 1998
The gutter time is determined ·by assuming an initial time of concentration, T; (may use To for the
parkway or a lot) and calculating ail initial Q,. To determine the velocity in the gutter, divide Q;
by 2 to obtain an average flow. Use this average flow with the graph in the Appendix to
determine an average velocity, V, for this gutter length, L.
Tg=L/(Vx 60).
Add this gutter time to T0 to obtain a new time of concentration, Tc, Use this new Tc to calculate
a new Q/2 and determine a _new Vave, in order to calct,tlate a new Tg, Repeat procedure until
assumed T~ == T0 + Tg,
4.3.3 Travel Time (T,)
Travel time is the time required fo,.-flow to travel the length of the storm drain to the point in
question. Travel time is calculated by using the following formula:
Travel Time = L/(V x 60),
where
L = Pipe length (feet) and
V = Velocity of flow in pipe (ft/sec).
4.4 Determination of Areas
The area (A) of each drainage basin was determined from the Drainage Area Map. See the
Developed D,.-ainage Basins Exhibit.
4.5 . Modified Rational Method
The Modified Rational Method was utiliz~~ to cl\lculate peak storm water flows and route the
calculated flows through the proposed drainage system.
REP/12244DR.DOC 7
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File: 1224.40
November 1998
When two flows combine at a junction point, the smaller of the flows has been decreased by
using the Modified Rational Method. This procedure accounts for the differing times of
concentration for the flows upstream of the junction point. the smaller Q is reduced by either the
ratio of the intensities or the ratio of the times of concentration, according to the following
procedure:
• Let Q, T, and / correspond to the tributary with the largest discharge.
• Let q, t, and i correspond to the tributary with the smallest discharge.
• Let Q and T correspond to the peak discharge .and the time of concentration
when peak flow occurs.
If T > t, the peak discharge is corrected by the ratio of the intensities:
Q = Q + q(Ih) . and T=T.
If T < t, the peak discharge is corrected by the ratio of the times of concentration:
Q. = Q + q(Tlt) and T=T.
4.6 Hydrology Calculations
The existing condition of the project site is undeveloped. All runoff is natural overland flow
which is concentrated and deposited in an existing desilting basin. Therefore, t:he predevelopment
hydrology calc-qlation is based on the assumption that the whole drainage area is· one basin with
natural overland flow, to determine the time of concentration and peak discharge. The
calculations are shown in Table 1.
The hydrology calculations for the developed condition are shown in Table 2. Each basin is
identified relative to the pipe system-used to collect runoff from it. Basin areas, C-factors, lengths
of .flow paths, slopes of flow paths; times of co:t;1centration, intensities, and total flows are also
listed.
'REPll2244DltDOC 8
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REP/122~DR.D0C
Table 1. PredevelopmeniJ[ydrology Calculations
Surface Runoff for 100-Year/6-Hour Storm
9
File: 1224.40
November 1998
--------------------08-N()y-98 DETAILED PRAINAGE CALCULATIONS
. Proj.:t'fame: KELLY RANCH VILLAGE 'F'
Ptoj. Num: 1224.4 Frequency 100 yrs. DSND by: SM
. File Name: l~24PRE;WQ1 .. P6= 2.6 CHKD by: MW
From To Typ~ of L H Pipe Slope Velocity Tc Revised Intensity C A-CA Sum Total Q
Node · Node Travel (ft) (ft) Dia(in) (ft/ft) (ft/s) (min) Tc (in/hr) (ac) · Ca (cfs)
SUBBA~IN Al
Natural Ovrlnd 650 38 OJ)58 . 3.4· 13.4 3.63 0.45 2.7 1.2 1.2 . 4.4
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REP/12244DR.D0C
Table 2. Postdevelopment Hydrology Calculations
Surface Runoff for lO0-Year/6-H;our Storm
. 11
File: 1224.40
November 1998
---------~---------08-Nov-98 DETAILED DRAINAGE CALCULATIONS
·Proj. Name: KELLY RANCH VILLAGE 'F'
.Proj. Num: 1224.4 Frequency 100 yrs. DSND by: SM
File Na111e: 1224FHYD.WQ1 P6= 2.6 . CHI~D by: MW
From To Type of L a Pipe Slope. Velocity Tc Revised Intensity C A CA ~um , TotalQ
Node Node. Travel (ft) (ft) Dia(in) (ft/ft) (ft/~) (min) Tc (in/hr) (ac) . Ca (cfs)
SUB:BASIN Al
Urban Overland . 650 · 38 0.058 · 10.2 , 10.2 4.33 0.7 2.7 1.9 1.9· 8.2
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SECTIONS
FLOOD ROOTING CALCULATIONS
File: 1224.40
November 1998
The storm drain pipes for the proposed systems were designed based on Manning's equation:
where
Q = (1.486/n) X A, X ?-'3 X s112,
n = Roughness coefficient,
A = ·Cross-sectio~al area of flow,
r = Hydraulic radius, and
s = Slope of culvert.
5.1 Flood Routing Method
The Modified Rational Method was utilized to calculate peak storm water flows and route the
calculated flows through the drainage system.
When two major basins combine at a junction point, the smaller of the flows has been decreased
by using the Modified Rational Method. This procedure accounts for the differing times of
concentration for the flows upstream of the junction point. The smaller Q is reduced by either the
ratio of the intensities ot the .. ratio of the times of concentration, according to the following
procedure:
• Let Q, T; and / correspond to the tributary with the largest discharge.
• Let q, t, and i correspond to the tributary with the smallest discharge.
• Let Q and T ~orrespond to the peak discharge and the time of concentration
when peak flow occurs.
~P/12244D R.DOC 13
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· If T > t, the peak discharge is corrected by the ratio of the intensities:
Q =Q+q(Ili) and T:;:::: T.
If T < t, the peak discharge is corrected by the ratio of the times of concentration:
Q=Q+q(Tlt) and T=T.
5.2 Pipe Flow
File: 1224.40
November 1998
Travel time has been considered between the nodes of the flood-routed system. Travel time is
calculated by using the following formula:
Travel Time = L/(V x 60),
where
L = Pipe length (feet} apd
V = Velocity of flow in pipe (ft/sec).
5.3 Flood Routing Tables
A flood routing table for each pipe system has been· prepared, using a hydrology program which
consists of a system of macros developed within the QuattroPro software. A printout for each
pipe system for the developed condition has been included in Table 3.
REP/12244D R.DOC 14
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REP/i2244DR.D0C
Table 3. Flood Routing Calculations
Flood.Routing for 100-Year/6-Hour Storm
15
File: 1224.40
November 1998
-------------------26-0ct-98 -DETAILED DRAINAGE CALCULATIONS
Proj.Name: KELLY RANCH VILL.A,GE 'F·;
Proj. Nuin: 1224.4 Frequency 100 yrs. J?SND by: SM
File.Name: 1:z24FHDC.WQ1 P6= 2.6 CHKDby: MW
From To Type of L H . Pipe Slope Velocity T~ . Revised Intensity C., A CA. . S111n . Total Q
Node Node Travel (ft) (ft) -Dia(in) (ft/ft) (ft/s) (min) Tc (in/hr) (ac) Ca (cfs)
Node to Node lA 2A , -
Input Flow . T~-:-5.J 6.76 8~2
Pipe Flow 71.65 15 18 0.209 20.3 0.1 5.2 6.68 0 0 0-0 8.2
Did Calculated= 0.28
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6.1 'F' Type·Catch Basin
SECTION6
INLET DESIGN
File: 1224.40
November 1998
The maximum allowable fl.ow rate is determined. using the orifice fl.ow equation, as follows:
where
Therefore,
C = Coefficient of discharge (0. 74) from Table 4-9,
King's Handbook of Hydraulics;
A =· Area of clean opening (3 feet x 0.65 foot=
1.95 ft2· per opening);
g = Gravitational acceleration (32.2 ft/sec2); and
h = Allowable height ofponded water (1.0 foot).
Qmax = (0.74)1.95~(2)(32.2)(1) ~ 11.5 CFS per opening.
The required number of openings for
Basin Al is 1. (Q100= 8.2 CFS.)
6.2 Curb Inlet at Sag (Ultimate Condition)
· From the City of San Diego Drainage Design Manual, Nomogram Chart 1-103.6C (refer to
Appendix A-5):
REPi12244DR.DOC 17
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Assuine
Therefore,
H = 0.73 foot (measured from bottom of the opening
to 0.1 foot below top of curb) and
h = 0.50 foot (height of the opening of curb inlet).
Hlh = 0.73 foot/0.5 foot= 1.46.
Q!L = 1.5 CFS/foot.
The City of Carlsbad allows the use of 1. 7 CFS/foot for curb inlet design.
The required curb inlet length for Basin Al is 5 feet (Q10o = 8.2 CFS).
REP/12244DR.DOC 18
File: 1224.40
November 1998
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SECTION7
OUTLET DESIGN ANALYSIS
File: 1224.40
November 1998
Riprap protection is provided at all outlet$ which discharge into unprotected natural areas, to
minimize potential for erosion in these areas.
Riprap rock class and apron thickness are determined in accordanc~ with the Standard
Specification for Public Works Construction, dated 1997 (see Appendix A-4). The riprap apron
width and length, are based on the San Diego Regional Stan.dard Drawing No. D-40.
Riprap calculations ate summarized in Table 6 below:
Table 6. iliprap Calculations Summary
Pipe Median Stone Apron
Location .Diameter Flow Velocity Rock (Size DS0) Width Length (inches) (CFS) (FPS) Class (feet) (feet) (feet)
.. -
Inside Detention Basin 18 8.2 203 2Ton 5.4 5 10
!l£P/12244DR.,;>OC 19
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. SECTIONS
SWALE CAPAClTY CALCULATIONS
File: 1224.40
November 1998
The swale at the top of slope along the western portion of the site is to collect overland storm
water from the site, and carry it into an underground drainage system to the detention basin.
8.1 Capacity of Swale
Ditch Width= 2 feet. Maximum Depth= 1.0 feet. Slope = 1.0%.
Maximum Capacity:
From King's Handbook, Table 7-14:
where
Q == (K: ln)d 813S1n.,
D = Depth of water::::;: 1.0 feet (when carrying Qmax),
d = Diameter of channel = 2 feet,
S = 0.01,
Did= 0.5,
K: = 0.232, and
n = 0.017.
Q = (0.232/0.0l 7)(2)813(0.01)1n. = 8.7 CFS.
The peak discharge collected by .the swale in Basin Al is Qp = 8.2 CFS, which is less than 8. 7
CFS. Therefore, the swale size is appropriate.
REP/12U4DR.DOC ,20
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SECTION9
DETENTION BASIN CAPACITY
File: 1224.40
November 1998
The exi~ting detention basin was designed per CT 83-30, Drawing No. 258-3A. The post
development flow calculated per thatreport is Q50 = 9.1 CFS.
The post cjevelopment flow from Village F to the detention basin is Qzoo = 8.2 CFS, which is less
than 9.1 CFS. Therefore the detention basin has the capacity necessary.
REP/12244DR.DOC 21
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SECTIONl0
.
REFERENCES
File: 1224.40 ·
November 1998
• Standards for De~ign. and Construction of Public Works Improvements in the City of
Carlsbad, dated April 1993.
• County of San Diego, Department of Public Works Flood Control Design: Hydrology
Manual, October 1973, revised April 1993.
• City of San Diego: Drainage Design Manual, April 1984, revised March 1989.
• VTN San Diego: Detention -Desilting Basins for Kelly Ranch, prepared for Kaufman and
Broad (CT 83-30).
REP(12244DR.DOC 22
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REP/12244DR.DOC
APPENDIXA
HYDROLOGY DESIGN CHARTS
A-1
File: 1224.40
November 1998
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TABLE 2
RUNOFF COEFFIClENTS (RATIONAL METHOD)
DEVELOPED AREAS (URBAN)
Land Use Coefficient{ C
Soil Type 1)
Residentia_l:
Single ·Famiiy
Multi-Units
Mobile Homes
Rural (lots greater than l/2 acre)
Commercial (2)
80% Impervious
· Industrial (2) I :~ • ... •
90% Impervious . ··r .. : .•.
~~~~~: .. \ ; . --:.·. ·. ~ .~. ·--,.: 'i.1 ~ ...
Q
.55
.10
.65
.45
.85
.95
(i>i::>i-~Izye~,Q. $<?J~. ~o:~-~e.d for all.~r~!li~.1-~1 --~9t1 ~-'!):~ .. -:-:, · ·::
·(2)~t ip~~ :-~ hctua.l-t . b)fi<fitlons= !_ cfe~fl¥tr-;i~l~fir. ~~fr~m· ,: \he tabul~ted
;·c. ,,tiiH.~pe-~~~n~s. ~~~ -qf _gg%::or::.9,0~fttliemlues··glvch··for;-.o,efficlcnt c,
· .may be revised by mtiltlplytng· SQ% or ·90% .. ,bY-:.the. ratio of actual
lmpervlousnes~ t~. the tabulated Impervloµs~j;0 ff~wever;· 1n no case shall
the final coef flclent be less than 0.50. For ·example: Consider oommerclal . .. . . .. . _. ',-:':·1:.Rroperty on D ~11~:f , ·., -:.. ; :•-. .-.~,·i· •' • ,:,7,L t:· ~!-··-.:·
·. :.: . .--···· _,: · ·Aci~-i:1~rv1ous~eer?rl: ·::-~f\.') t:e '.:=; so%:.
.. ./Q~t . ·t:· .. ~1 :·-, •. ::,, l(t: · .. _, .... -: ·:ci ._ ..... ';·· ! ..
Tal>ulated imperviousness · = 80%
Revised C = ~ x 0.85 = 0.53
..... . --.
82 APPENDIX A-1
----·-·---------·-----JNTENSITY-DUfy\T; DES!GH CHART
I • Inten·sity (ln./Hr.)
6 Hr. Prc:cipitatiol'.' (In: )ij
l
~
t .e .I PTfTJJJTQ rm [ m r1rmnmrmm m llll lllH1111111mu I I I I i I i I ' '.' ' 'I " "'I" "'I
· 1 o 1 s · 20 30 40 so· 1 2 3 4 s s
1,.H,,11+0~ Hours
1 Dire~tion_s for Application:
i) ·From precipitation r:,aps detennine 6 hr. a
24 hr. amounts for the selected frequency These maps are printed in th~ County Hydr
Man~al (10, 50 nnd 100 yr. maps included
Design and Procedure Manua.l).
2) Adjust 6 hr. precipitation (if neces·sary)
that it is within the range of 451 to 65Z
the 24 hr. precipitation. (Mot nr,plicabl to Desert)
3) Pl~t 6 hr. precipitation1 on the right si
of the chart..
4) Draw a 1:f.ne through the point parallel t
plotted lines.
yr. ---
65
2) Adjusted *P 6= ~,<:b
3) tc a ______ min.
4) Is: ____ in/hr.
*Not Applicable to Desert Region
APPENDIX X
IV-A-14
Revised l;
-·--·--· ------1111111 --· ---:--
')>
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COUNTY OF SAN DIEGO
DEPARTMENT OF SANITATION&.
FLOOD CONTROL
45'
30 1 I
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15 I '.
33° !
100-YEAR 6-HOU~ PRECIPITATION
~20__,; ISOPLUV.IALS foF 100~ YEAR 6-HOUR
PRECIPiTl\TIOrl
45 1 I I I __ fl' \1AIU 1111.1.11 ,--:;1
Prep11+,d by
U.S. DEPARTMENlf OF COMMERCE
NATIONAL OCEANIC AND AT1.IOSPHERIC ADMINISTRATION
SPECIAL STUDIES BRANCH, OFFICE OF HfDROLOGY, NATIONAL WEATHER SERVICE
30 I 4 --
1181 45' 30 1 15 1 117° l•S I 30 1 ) 5 I 116°
,. ,,...__ • ___ .,<';_...T"\_r "l~T ~
-_, ------------------·-C0UNTY OF SAN DIEGO
DEPARTMENT OF SANTfATION&
FLOOD CONTROL
lOO•YEAR 24-HOltR PnECIPITATlON
,-20../ISOPLUV-IALS OF lOO -YEAR· 24-HOUR . I
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33° -i:--------+-------~-----..J.~t -> ......... ·-'
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Prcp1a,fo<I by
U.S. DEPARTMENtf OF COMMERCE
NATIONAL OCEA:<;IC AND A1':.IOSPHERIC ADMINISTRATION
SPECIAL STUDIES BRA~CII, OFl'ICE Of" 11fDROLOOY, NATIONAL WEATHER SERVICE
30'
11 ft 115 I 30 1 1'i'
Et.lTHS OF AN lfJ.CH
117° JI !i I JOI
Revised 1/85
I :, I 116°,
APPENDIX XI-I
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SAN ()I E~O COUNTY
DEPARTMENT OF SPECIAL DISTRICT SERVICES
DES I GN MANUAL
. APPROVED ·."'·· ·t 'e··'./, •• ,. • .,-Cc'-,
84
0
NOMOGRA?H FOR DETERMINATION
OF TIM6 OF CCNCENTRATIOfl: ('ic)
FOR NATURAL WATERSHEDS
APPENDIX A-3. 1
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TlME
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w t I i-:--.r. • ... •IT .... •-
~ 400
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E. X A t-1\ P L·e.. :
OF FLOW
KLAl\l U
CURVES
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30
(;,(VE.N. L-.E.NG1H OF FLOW c. 400 FT.
'R.£.AD • ,
S l-OPe:.,.. l. 0 o/o
COE..FftC.tE.-NT OF-Rvt,-10F{= C :: • 70
OVE=-KLAND f=LDW1\ mt-::.
86
l5' Mt"1Ua£.5
A-PPENDIX A-3. 2
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1-
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t,ater,a, Table 200·1.7
, Eiht:t Bbolccl CJ) [ lppt:c [ ;.ay.c:c(&)
Vd. Roel:: Riv~ Fl/Sec Cbu 'I'lutx·
(1) (2) Del' Opt.l Opt.2 Opt.3 l..ov,.,cr
"T" Scc.:200 Scc.400 (S) Layer
(.C) {.C) (61
..
fr7 No.3 .6 3/16" C2 D.O. -Bacl:-
11,:
7-1 No.2 1.0 l/4~ B3 o.o. -~k-
iu
1--9.S Fae--I.' 3/r -0.0. -. 11,:
9S·ll. Ught 2.0 ½" -314• -1-112·
P.B.
11/13 "1'/4. '/-1 3/4" -314• SAND
TON 1-112·
P.B.
13-lS ½ 3 • .C 1" -314• SAND
TON : 1-112·
P.B.
15-17 • 4.3 1-.112· -TYPE SAND
.TON . B
17-2:> 2 S.4' 2· TYPE SAND
· TON B
See 200-1.6 · See also 200-1.G(A)
Practical use of this table is limited to situations
where 11T11 is less than inside diameter.
(1) Average velocity in pipe or bottom velocity in
energy dissipater, whichever is greater.
(2) · 1f des.ired riprap anc:f filter blanket class is not
available, use next larger class.
(3) Filter blanket thickness = 1 Foot or 11t 11 , whichever
is l~ss.
(4) Standard Specifications
CCX)Struction. ·
for ·Public \lorks
(5) O.G. = Disintegrated Granite, 1 KM to 10 KM.
P.B. = Processed Miscellaneous Base.
Type B = Type S bedding material, (mini nun 75¾
crushed particles, 100% passing 2%11 sieve, 10¾
passing 111 s i·eve).
(6) Sand· 75X retained on #200 sieve.
APPENDIX A-4
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CHART l-103.GC
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. CITY'-OF SAN··o1EGO ~-:~ DE$t.Gti :oii1oe~
NOMOGRAM ~ CA.PAClTY ., c·uR·s
INLET .. AT SAG
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SHT~ NO.
APPENP\)( A-5