GPA21-0008_Staff Report_Attach D- MND Appx G-Hydrology — San Marcos City Council, February 28, 2023

ATTACHMENT D

MITIGATED NEGATIVE DECLARATION

APPENDIX G

HYDROLOGY REPORT

PRELIMINARY

HYDROLOGY STUDY

FOR

SAN MARCOS RESIDENCES

2972 &2982 S SANTA FE AVENUE

APN:
217
-
161
-
18 CITY OF
SA

N MARCOS
, CA

PREPARED FOR:

SANTA FE FLORES LP

P.O. BOX 903

RANCHO SANTA FE, CA 92067

PREPARED BY:

PASCO LARET SUITER & ASSOCIATES
, INC
.

27127
CALL
E ARR

OYO, SUIT
E

1904

AN JUAN CAPISTRANO
, C
A 92675

949
-
661
-
6 695

Prepared
:

October

2021

Revised:

March

2022

Revised: April 2022

___________________________________________
_______

William J
. Suiter, RCE 68964

DATE

TABLE OF CO
NTEN
TS

SEC
TION

Ex
ecu
tive S
umm
ary

1 .0

Introdu
ction

1.1 Existing Conditions

1.2 Proposed Project

1.3 Conclusions

1. 4

References

1.5 Methodology

2.0 Rational Metho
d

2.1 County of San Diego Criteria

2.2 AES Rational Me
tho
d Computer Model

2 .3

Hydrolog
ic An
alysis

3.0 Exist
ing

Condi
tion

Hydro
logic Model Output

(
100
-
Year Event)

3.1 Proposed Condition

Hydrologic Model Output

3.2 (100
-
Year Event Undetained)

Detention
Analysis

3.3 Proposed Con
dition Hydrologic Mod
el
Output

3.4 (1
00 -
Y
ear Even
t De
t
ained)

H
ydr
omodif
ica
tion
M
anagement

3.5 Storm Water Pollutant Contr
ol

3.6 Ap
pendices

Appendix A: Hydrology Su
pport Material

Appendix B:

Detention Support Material

Appendix C:

Ex
isting and Proposed Hydrology Ma
ps

1.0 EXECUTIVE

SUM
MARY

1.1 Introd
uctio
n

This
Hydrology Study

fo
r
the prop
osed

development
has been prepared to analyze the
hydrolog
ic cha
rac
teristics of the

existing and proposed project site. This report present s

both
the methodology and the calculatio
ns
used fo
r determinin
g th
e
storm

water

runoff

from the
project s
ite in the

pre
-
developed (existing) conditions and the post
-
develope
d (pro
pos
ed)

conditions p
roduced by the 100
-
year
, 6
-
hour storm

event
.

1.2 Existing Conditions

The subject pro
perty is locat
e
d
at
2972 & 2982
S
. S
anta Fe Av
en
ue

the City of Vi
sta
. The site
is
west of Las
Flores Drive
,

north o
f South Santa Fe Avenue, and

approximately
1/4

mile

north

of the 78 freeway.

Vici
nit
y Map

The sit
e is surrounded by
residen
tial homes

to the
north
,
e
ast

and
south
,

a
n
d

industrial

o
ffi
ces

to the
west
.

The site

is
primarily
und
ev
eloped with a

shared access driveway a
t the property
’
s
southerly boun
dary
.

The driveway also provides access to the adjacent

commerci
al
property
’
s
pa
rking lot an
d
commercial b
uil
ding
.

The southern
portion of t
he site is re
latively flat while the
central portion
slopes

up to a
n elevated pad

at the north

en
d of the site
.

Las
Flores Drive a
long
the property
’
s east
ern boundary
has
approximately a 15
-
20 %
grade upward to the nor
th

al
low

vehicle access

over

the rai
l
road tracks
north of the property.

Elevations acros
s the
site
range

from

a
high of

approxi
mately
546

feet
in th
e no
rth
east

corner

of
th
e
property to

a low
of
approximately

494.50

feet
a
t
t
he

southwest

corner
of
the
pro
per
ty
.

The
project site

approx
ima
tel
y

2. 23

acre
s
.

In the existing condition
,
the project sit
e is divided
into
four

drainage basins

(see Pre
-
Project
Hydrology
Map in Appendix C
)
.

Drainage basin E1 consists of
t
he
north
erly half graded

p
ad

where

runoff

fl
ows

overland and
in
to
an existing
storm drain inlet structure
in the

center of the pad.

Captured
runoff exits the
site through an existing 18
”

RCP
at the easterly boundary and into
the public storm drain
system within Las Flores Drive.

Drainage Basin E2 i
s a

si
milar
, but much
s
maller, sum
p
condition
into a

storm drain inl
et structure exists

just southerly of the

north half
sump
condition mentioned above. Capture
d

runoff
also exits the sit
e through a separate 18
”

RCP at
the easterly boundary
and into the pu
bli
c storm
drain syste
m within Las

Flores Drive where it
confluences with th
e north half

pad

runoff.

Pipe f
lows
continue

to travel southerly down Las
Flores Drive
before
combin
ing w
ith flows from a 54
”

RCP and 24
”

RCP
. C
o
mbined
pipe

flows
are
then diverted

the west
along S
o
u
th Santa Fe
Av
enue
through a

6 0
”

RCP.

Drainage Basin
E3 consi
sts of t
he south
ern half of the site
where
runoff generate
d

from the
adjacent li
quor stor
e property and the p
roject site

combines

to
surface flow southerly
.

Surface
runoff

ex
i
ts the drainage ba
sin through
the

existing
share
d ac
cess driveway on S
o
uth Santa Fe
Avenue

then

into the public street
’
s curb and gutter

and flows northerly

approximately
100
’

before being cap
tured by
an existing curb inlet structure. Cap
tured runoff
i
s
d
iverted across
S
out
h Santa Fe A
v
enue through an 18
”

RCP
storm dr
ain pipe and into a

60 ”

RCP th
at

continues
flowing
westerly
.

Drainage Basin

E
4 is locat
ed

a
long the west edge of

Drainage Basin
E1

north half pad,

a small
area of

e
xis
ting
grade
d

slopes

th
at

surface flow
s

to th
e west

and o
nto the adjacent property
.

Pe
r
the Unite
d States Department of Agriculture Web Soil Survey, the project site is

underla
in
with
Hydro
lo
gic So
il Group
C

and D
.

Refer to

Appendix A for soil information.

Area weighted runo
ff

co
efficients were cal
culated usin
g the methodology described in
se
cti
on

3.2.1 of

the San Diego County Hydrology Manual and Table 3
-
1 Runoff C
oefficient
s for Ur
ba
n
Areas.

Us
in
g

the
Rational M
ethod Proc
edure outlined in the San Diego County Hydrology
Manu
al
, a

peak flow rate was

calculated
for the
existing condition

100
-
ye
ar,

6 -
hour sto
rm
event.

The

following

table

summarizes the existing condition hydrologic

data.

Su
mmary of
Ex
isting Condi
tion
1 00
-
yr Peak

Discharge Rates

Drainage Basin

Area (ac)

Q10
0 (
cfs)

1.24 2.35

0.04 0.1
0 E3

1. 65

5.16 E4

0 .12

0.31 Refer to the existing condition hydrologic calculations includ ed in
S
ection

3 .1
for detaile
d
analysis.

1.3 Propos
ed Pr
oject

The pr
oject

prop
oses to
devel
op the existing

site
into a

54 -
unit

m
ult
ifamily

residentia
l

development

consist
ing

of
1 -
bed/1
-
bath

units and 2
-
bed/
2 -
bath units
, access drive
,

parking
stalls,

landscape, associated
utilities and
improvements
,
proprietary
bi
ofiltration systems

to
meet
the requi
rements for po
llutan
t

cont
rol

and

un
der
ground storm wat
er storage f
aciliti
es

to
meet the requirements for
hydromodification management flow control and to mitigate for the 100
-
year 6
-
hour storm event.

In the proposed conditio
n, onsite storm water runoff
will be collec
ted in

propo
sed s
tor
m
dra
in
system
and
conveyed to
the proposed
prop
rietary biofiltration syst
em

(BMPs)
and
subsequently the proposed underground storage facilities (BMPs) .

Two

storm drain systems
,
each with their own BMPs,

are proposed to maintain the site
’
s historical po
int
s of discharge
.

the propose
d condition,
the
project
site
consists of

five

d
rainage basins

(see Post
-
Project
Hydrology Map in Appendix C)
.

Drainage Basin P1

consists of the proposed site
’
s upper

level buildin
g,

north

parking lot

area

and a porti
on o
f e
xisting

public

ROW
hillside are
a that
drains into the p
roject

site

at the
northeast corner
of the property
.

Surface
runoff
will sheet flow

south
westerly

across

the
parking

area
, through a curb opening and into
a
proprietary bi
ofiltration system.

Treat
ed

fl
ows
and p
eak flows

will enter t
he private
storm drain pipe system

then

divert

pipe flows

to a
n

underground storm water storage facility

before exiting the project site through an existing 18
”

RCP storm drain pipe that flows out into the public storm dra in

system in Las Flore
s Drive.

Dr
ainage Basin P2 consists of the proposed sites
’

lower level building, south parking lot area
,

and
access road
.

Surface

runoff will sheet flow south
erly down the access road
,
across the
parking area

then
through

curb openin
gs
int
o one of two pro
p
rietary bio
filtration systems
.

Treated flows and peak
flows will enter the

private sto
rm drain pipe syste
m then

divert pipe
flows to
an underground storm water st
orage facility before

exiting the project site through a
new

18 ”

RCP st
orm

drain pip
e and con
nect to the
existing 60
”

RC
P storm drain pipe in South
Sant
a Fe Av
enue.

Drainage Basin P3 consists of th
e adjacent property
’
s
existing
commercial

building,

existing

parking
area and existing undeveloped hillside

to the west of the
p
roj
ect site.

new

con
crete
ditch

is proposed

along the project site
’
s westerly boundary along the new access road

and a
new ribbon gutter along the existing parking area to cap ture off
-
site runoff

without comingling
with on
-
site runoff

and
divert
the
surf
a
ce

flows
out
onto Sou
th Santa Fe
Avenue as in the
existing condition.

Drainage Basin P4 consists of the
ex
isting hillside area at the
n
orthwest corner of the site
.

Storm water runoff will

surface flow
westerly and
onto the adjacent property as in the ex
ist
ing
condition.

Dra
inage Basin
P5 consists of the
existing

public right
-
of
-
way

hillside area
at the northeast
corner of the project site
.

A new concre
te ditch is proposed along the project
’
s east
erly
boundary to capture off
-
site runoff
from the hillsi
de

wi
thout comingling wi
th on
-
site r
unoff and
divert the surface flow to

a
n
underground

storm drain pip
ing system
to

conflu
ence w
ith runoff
from Draina
ge Basin 1
.

Pipe

flows

will combine with Drainage
Basin 1
p
ipe

flows

(downstream
of its BMP systems)

and ex
i
t
the site through an

existing 18
”

RCP storm drain p
ipe that flows
out into the public storm drain system in Las F
lores Drive.

The
BMPs

will provide hydromodification ma
nagement flow contro
l and storm wat
e
r pol
lutant
control to meet the requirements the
Cal
ifornia Regional Wa
te
r Quality
Control Board San
Diego
Regio
n municipal storm water
permit (O
rd
er
No. R9
-
2013
-
0001, referre
d to as MS4
Permit).

For detailed pollutant c
ontrol and HMP calcu
lations refer t
o

the
report
titled “Priority
Development Project

(PD
P)

Storm Water Qual
ity Mana
geme
nt Plan

(SWQMP)

for
San Marcos
Residences
” dated
March

2021
,
p
re
p
ar
ed by Pasco

Laret
S
uiter

& Associates
.

Ar
ea weighted
runoff coefficient
s w
er
e
c
alculated u
sing the methodology described in section

3.2.1 of the San
Di
ego

C
ounty Hydrolo
gy M
anual and T
a
ble
3 -
1 Runoff Coefficients for Urban
Areas.

Using the Rational Met
hod Procedure
outlin
e
d in
the San Diego

Count
y Hydrology
Manual, a peak flow r
at
e w
as calculat
ed for the
proposed condi
tion

100
-
year, 6
-
hour storm
event.

T
he
un
derground storm w
ater storage

facil
ities

provide
mitigat
ion

for the

100
-
year 6
-
hour storm event.

A detention a
nalysi
s

w
as
performed to
eva
luate the effects of the storage
facilities

on the
100
-
year, 6
-
hour storm event

peak discha
rge rates.

The

followi
ng

ta
ble

summarizes th
e
proposed

c
ondition h
ydrologic data
.

Summary of
Prop
osed

Condi
tion
100
-
yr Peak Di
scharge Rates

Drainage Basin

Area (ac)

Q100 (cfs)

Un
detained

Q100 (cfs)

D
etained

P
1 &
P
2 1.25

5.71 0.69

P
3 1.07

6.44 4.02

0. 66

2.90 N/
A

0.0 6

0 .
1 6

N/A

Refer

t
o
the
propos
ed undetained and detained hydrologic

calculations
and detention analysis
include
d

in S
ection
s

3. 2
,

3.3 ,

3.4 a
nd Appendix B

for deta
i
led analysis.

1.4 Con
clusions

Based upon the analyses
included in this report,

the pr
opose
d
pro
pr
ieta
ry biofiltra
tion devices

and underground sto
rage

facilities

are

sized to accommodate
the increase in peak runoff i
n

the
proposed

condition and
ar
e
des
igned
to me
et t
h
e requirements of
the MS4 Permit for both
pollutan
t control and hydromodif
ication ma
na
gem
e
nt.

1. 5

References

“San Diego County Hydrology Manual”,
revised June 2003, Count
y of San Diego, Department of

Publi
c Works, Flood Control
Se
ct
ion
.

Soi
l Sur
vey
S
taff, Natural Reso
urces Conservation Service, Un
ited States Department of
Agricultur
e.

W
e
b Soi
l Surve
y. Available

online at
http://websoilsurvey.nrcs.usd
a
.gov
.

2.0 METHODOLOGY

Pursua
nt

t
o t
he San

Dieg
o Co
u
nty Hydrology Manu
al
(SDCHM)
dated June 2003, the Ration
al
Method is recom
mended f
or

a
naly
zi
ng th
e run
o
ff response

from drainage areas up to
approximately 1 square mile in siz
e. The
proposed

project and a
s
socia
ted watershed basins ar
e
le
ss
than 1

squa
re m
i
le, therefore the
Rational Method was used to analyze th
e project’s
hydrol
ogic cha
ra
ct
eris
ti
cs in

the
e
xisting and

proposed conditions.

2.1 Rational Method

The Rational Method (R
M) formula estimates the peak

rate
of runoff based on the
va
ri
abl
es of
area,

run
o
ff coefficient, an
d rainfall intensity. The rainfall in
tensity (I) is equ
al to:

I
=

7.44 x

P
6 x D
-
0 .
645

Where:

I = Intensity (in/hr)

P
6 = 6
-
hour precipitation (in)

D = duration (min
–

use Tc)

Using

the Time of Concentrat
io
n
(Tc
)
whic
h

is the
t
i
me required for a

given element of water
that originates at t
he most remo
te point o
f
th
e
basin be
ing
a
nalyze
d to
reach the point at which
the runoff from the basin is being a
nalyzed, the RM equation dete
r
mines

the storm water
runoff

rate (Q
)
for

a given
b
a
sin in terms of f
low
,
typically in cubic feet per second (cfs
).

The RM
eq
uation is
as

f
ol
lows:

Q =
C
IA

Wh
ere:

Q= flow (cfs)

C = runoff coefficient, ratio of rainfall t
hat produces storm water

r
unoff

(runoff vs. infiltrati
on/evapo
ra
tio
n/absorpt
i
o
n/etc)

I = aver
age rainfall intensity for a duration equal

to the Tc fo
r the

a
re
a
(i
n/hr)

A =
d
rainag
e are
a contributing to the basin (ac)

The RM equation assumes th
at the storm event being anal
y
zed d
elivers precipitation t
o the
en
ti
re
basin uni
f
o
rmly, and therefo
re the peak discharge rate will occur when
a raindrop th
at
falls a
t
th
e
most re
mote
p
ortion

of t
he basin arrives at the point of analysis.

The RM also
assume
s that the fraction of rainfa
l
l tha
t becomes runoff or the

runoff
co
eff
icient
,

C
,

not
affected b
y the storm intensity, I, or the precipitati
on zone numb
er.

2.2 Co
unty

San Die
g
o Crit
eria

T
he County of San Diego has developed its own tables, nomographs,

and methodologies for
ana
l
yzi
ng

storm water runoff for

areas within

t
he
Coun
t
y. Th
e County has

also developed
precipitation isopluvial contou
r maps th
at show ev
en

lin
es
of rainf
a
ll ant
icipat
ed from a given
storm event (i.e. 100
-
year, 6
-
hour storm). The 1
00 -
year 6
-
hour storm event

rai
nf
all isopluvi
al
map is i
ncluded in Ap
pe
ndi
x A
.

One o
f

the
variab
les of the RM equation is

the ru
noff coefficient
,
C
,

w
hi
ch is depe
nd
e
nt
upon
land us
e and soil t
ype. Table 3
-
1 Run
off Coe
fficients for Urban Are
as in the SDCHM
ca
tegorizes
the land use,
t
he
as
sociate
d develo
pment de
nsity (dwelli
ng

un
its
p
er acr
e
) and

the p
ercentage
of impervious a
rea. E
ach of the categories
li
sted has a
n
a
sso
ciated runof
f coefficien
t for each
soil ty
pe clas
s. A composite
runoff
coefficient

can
al
so be calculated for an
a
rea

b
ased on

soil
ty
pe and i
mpervious per
ce
nta
ge u
s
ing th
e

foll
owing

equation

from Section 3.1
.2 of t
he SDCHM
:

C = 0.90 ×
(%

Imperviou
s)

+ C
p × (1
-

% I
mpervious)

Where: Cp = Pervio
us Coef
ficient Runoff Value fo
r the soil type

(shown in

Tab
le

3 -
1 as U
ndisturb
ed Nat
ural Terrain/
Pe
rma
nent

Open

Space, 0% Impervious)

The
ons
ite hydrologi
c
calcula
t
ions
conta
in
ed

h
erein figure

a composite

runoff coefficient for th
e
onsite project areas
based on the pe
rce
ntage of impervious are
a

an
d
the percentage of
pervi
ou
s or landsc
ap
e a
rea.

Refer to Appendix

A for runoff

coefficient calculations.

The

County has
also illus
tr
ated

in detail t
he methodolo
gy for determini
ng the time of
concentration
, in par
ticular

the i
nitial time of concentrat
i
on.

T
he County has adopted t
h
e
Federal Av
iation Ag
e
ncy’s (F
AA) overla
nd time of flow equation.

Th
is

eq
uation esse
ntially limi
ts
the flo
w
path

length for
the initial
time of concen
tration to lengths of 100 feet

or le
ss, and i
s
depe
ndent on land use and slo
p
e.

2.3 A
ES Rational Method Comp
u
ter Model

Th
e Rationa
l

Method
computer p
rogram developed by Advanced

E
ngi
neering Sof
tware (AES)
satisfies
th
e Co
unty of San
Diego design

criteria, the
refore it is the computer mode
l used

for
this

study
. The AES hydrologic mode
l

is c
apable of creating inde
p
endent node
-
link mode
l
s of
eac
h interior

drainage basin and linking
th
ese

sub
-
models

together at

confluenc
e
poin
ts to
determ
ine peak flo
w rates. The p
rogram utilizes base informati
on inp
ut by the

user
to perform
calculations f
o
r up
to 15 hydrologic proces
s
es. The requ
ired base

informat
ion includ
es drainage
basin area, stor
m
wat
er facility

locations a
nd sizes,
la
nd u
ses, flow pa
tterns, and
topographic
el
evations. The hydrologic condi
tions
were anal
yzed i
n accordance with the 200
3 Coun
ty of San
Diego Hydrolo
g
y Manual cri
teria as
f
ollows:

Design St
orm

100
-
year, 6
-
hour

1 00
-
ye
ar,

6 -
hour Pre
cipitation

3 .
3 inches

Ra
infa
ll Intensity

Based on th
e 2003 County
of San Diego Hydrology
Manual
criter
ia

Runoff

Coeff
i
cient*

P
ervious
C

soil

0.3 0

P
ervious D
soil

=0.
35 Impervious

soil

C = 0.90

Impervious

soil

C = 0.90

Soil Ty
p
e

C & D

*Weighte
d

runo
ff coefficie
nts were ca
l
c
ula
ted where a
p
propriate
. Refer to Appendix A.

3.0 HYDROLOGIC ANALYSIS

Table 1 below
c
ompares and
summarizes the hydrolog
ic
ca
lculations

provi
ded in Secti
o
ns 3.1,

3.2 and 3.4.

Table
1: Summary of 100
-
yr P
e
ak Disc
harge Rate
s

Exi
sting

Propos
ed

Proposed
(
Det
ained
)

Drainage
Basin ID

Area
(ac)

Q100
(c
fs)

Drainage
Basin ID

Area
(ac)

Q100
(cfs)

Drainage
Basin ID

Area

(ac)

Q100
(cfs
)

E
1 1.24

2.35 P1 &
P
2 1.25

5.71 P1 &
P
2 1.25

0.69 E
2 0.04

0.10 P3

1.07 6.44

1.07 4.02

E
3 1.
6 5

5.16 P4

0. 66

2.90 N/A

E
4 0
.12

0.31 P
5 0.0
6 0.
16 N/A

Existing

Proposed

(
Detained
,
Cumulative
)

Drainage
Basin ID

Area
(ac)

Q100
(c
fs)

Drainage Basin ID

Area (ac)

Q100 (cfs)

E
1 ,

E2 & E3

2.93 7.61

P1
, P2, P3

& P
4 2.9
8 7.61

0.12 0
.31

P
5 0.0
6 0.16

3.1 Exis
ting Conditi
on

Hy
drologic Mo
d
el Output (
100
-
Year Event)

____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1452
Analysis prepared by:

PASCO LARET SUITER & ASSOCIATES

27127 CALLE ARROYO, SUITE 1904

SAN JUAN CAPISTRANO, CA 92675

ph 949.661.6695

plsaengineering.com
************************** DESCRIPTION OF STUDY ************************** * 3527 SOUTH SANTA FE * * EXISTING CONDITION * * 100-YEAR * ************************************************************************** ---------------------------------------------------------------------------- FILE NAME: 100PRE.DAT
TIME/DATE OF STUDY: 15:49 03/01/2022
---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
---------------------------------------------------------------------------- 2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.300
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) === ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
**************************************************************************** FLOW PROCESS FROM NODE 100.00 TO NODE 105.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 85
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 575.97
DOWNSTREAM ELEVATION(FEET) = 538.97
ELEVATION DIFFERENCE(FEET) = 37.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.684
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.210
SUBAREA RUNOFF(CFS) = 0.28
TOTAL AREA(ACRES) = 0.13 TOTAL RUNOFF(CFS) = 0.28 **************************************************************************** FLOW PROCESS FROM NODE 105.00 TO NODE 110.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 538.97 DOWNSTREAM(FEET) = 532.40 CHANNEL LENGTH THRU SUBAREA(FEET) = 149.00 CHANNEL SLOPE = 0.0441 CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 20.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.321
USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 85
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.34 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.64 AVERAGE FLOW DEPTH(FEET) = 0.07 TRAVEL TIME(MIN.) = 1.51 Tc(MIN.) = 8.20
SUBAREA AREA(ACRES) = 1.11 SUBAREA RUNOFF(CFS) = 2.10 AREA-AVERAGE RUNOFF COEFFICIENT = 0.300
TOTAL AREA(ACRES) = 1.2 PEAK FLOW RATE(CFS) = 2.35 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.10 FLOW VELOCITY(FEET/SEC.) = 2.05 LONGEST FLOWPATH FROM NODE 100.00 TO NODE 110.00 = 249.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 110.00 TO NODE 115.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 530.34 DOWNSTREAM(FEET) = 528.21 FLOW LENGTH(FEET) = 92.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 4.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.22
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.35
PIPE TRAVEL TIME(MIN.) = 0.25 Tc(MIN.) = 8.44
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 115.00 = 341.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 120.00 TO NODE 125.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 85
INITIAL SUBAREA FLOW-LENGTH(FEET) = 57.00
UPSTREAM ELEVATION(FEET) = 543.68
DOWNSTREAM ELEVATION(FEET) = 517.12
ELEVATION DIFFERENCE(FEET) = 26.56
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.047
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.643
SUBAREA RUNOFF(CFS) = 0.10
TOTAL AREA(ACRES) = 0.04 TOTAL RUNOFF(CFS) = 0.10 **************************************************************************** FLOW PROCESS FROM NODE 125.00 TO NODE 130.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 517.12 DOWNSTREAM(FEET) = 516.53 FLOW LENGTH(FEET) = 29.00 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 18.000
DEPTH OF FLOW IN 18.0 INCH PIPE IS 1.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 2.39
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.10
PIPE TRAVEL TIME(MIN.) = 0.20 Tc(MIN.) = 5.25
LONGEST FLOWPATH FROM NODE 120.00 TO NODE 130.00 = 86.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 135.00 TO NODE 140.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .4500
S.C.S. CURVE NUMBER (AMC II) = 85
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 538.13
DOWNSTREAM ELEVATION(FEET) = 517.74
ELEVATION DIFFERENCE(FEET) = 20.39
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.431
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.243
SUBAREA RUNOFF(CFS) = 0.82
TOTAL AREA(ACRES) = 0.22 TOTAL RUNOFF(CFS) = 0.82 **************************************************************************** FLOW PROCESS FROM NODE 140.00 TO NODE 145.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 517.74 DOWNSTREAM(FEET) = 494.68 CHANNEL LENGTH THRU SUBAREA(FEET) = 270.00 CHANNEL SLOPE = 0.0854 CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 20.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.947
*USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .4500
S.C.S. CURVE NUMBER (AMC II) = 85
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.06 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.73 AVERAGE FLOW DEPTH(FEET) = 0.09 TRAVEL TIME(MIN.) = 1.65 Tc(MIN.) = 7.08
SUBAREA AREA(ACRES) = 1.43 SUBAREA RUNOFF(CFS) = 4.47 AREA-AVERAGE RUNOFF COEFFICIENT = 0.450
TOTAL AREA(ACRES) = 1.6 PEAK FLOW RATE(CFS) = 5.16 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.13 FLOW VELOCITY(FEET/SEC.) = 3.24 LONGEST FLOWPATH FROM NODE 135.00 TO NODE 145.00 = 370.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 150.00 TO NODE 155.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 85
INITIAL SUBAREA FLOW-LENGTH(FEET) = 34.00
UPSTREAM ELEVATION(FEET) = 538.66
DOWNSTREAM ELEVATION(FEET) = 527.29
ELEVATION DIFFERENCE(FEET) = 11.37
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 3.898
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.

SUBAREA RUNOFF(CFS) = 0.31
TOTAL AREA(ACRES) = 0.12 TOTAL RUNOFF(CFS) = 0.31 **************************************************************************** FLOW PROCESS FROM NODE 150.00 TO NODE 155.00 IS CODE = 22 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 85
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
SUBAREA RUNOFF(CFS) = 0.31
TOTAL AREA(ACRES) = 0.12 TOTAL RUNOFF(CFS) = 0.31 ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 0.1 TC(MIN.) = 5.00 PEAK FLOW RATE(CFS) = 0.31
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

3.2 P
roposed
Undetained
Condition

Hydrolog
ic Model Output

(
100
-
Y
ear E
ve
nt)

____________________________________________________________________________ ****************************************************************************

PASCO LARET SUITER & ASSOCIATES

27127 CALLE ARROYO, SUITE 1904

SAN JUAN CAPISTRANO, CA 92675

ph 949.661.6695

plsaengineering.com
************************** DESCRIPTION OF STUDY ************************** * 3527 SOUTH SANTA FE * * PROPOSED CONDITION * * 100-YR * ************************************************************************** FILE NAME: 100PST.DAT
TIME/DATE OF STUDY: 10:31 03/02/2022
---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
---------------------------------------------------------------------------- 2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.300
SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

USER-SPECIFIED RUNOFF COEFFICIENT = .7700
S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 75.00
UPSTREAM ELEVATION(FEET) = 535.41
DOWNSTREAM ELEVATION(FEET) = 532.13
ELEVATION DIFFERENCE(FEET) = 3.28
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 3.146
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.

SUBAREA RUNOFF(CFS) = 0.33
TOTAL AREA(ACRES) = 0.05 TOTAL RUNOFF(CFS) = 0.33 **************************************************************************** FLOW PROCESS FROM NODE 200.00 TO NODE 205.00 IS CODE = 22 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .7700
S.C.S. CURVE NUMBER (AMC II) = 0
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
SUBAREA RUNOFF(CFS) = 0.33
TOTAL AREA(ACRES) = 0.05 TOTAL RUNOFF(CFS) = 0.33 **************************************************************************** FLOW PROCESS FROM NODE 205.00 TO NODE 210.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 532.13 DOWNSTREAM(FEET) = 529.64 CHANNEL LENGTH THRU SUBAREA(FEET) = 304.00 CHANNEL SLOPE = 0.0082 CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.013 MAXIMUM DEPTH(FEET) = 1.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.649
*USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .7700
S.C.S. CURVE NUMBER (AMC II) = 0
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.82 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.96 AVERAGE FLOW DEPTH(FEET) = 0.14 TRAVEL TIME(MIN.) = 2.58 Tc(MIN.) = 7.58
SUBAREA AREA(ACRES) = 0.96 SUBAREA RUNOFF(CFS) = 4.91 AREA-AVERAGE RUNOFF COEFFICIENT = 0.770
TOTAL AREA(ACRES) = 1.0 PEAK FLOW RATE(CFS) = 5.17 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.19 FLOW VELOCITY(FEET/SEC.) = 2.26 LONGEST FLOWPATH FROM NODE 200.00 TO NODE 210.00 = 7804.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 210.00 TO NODE 215.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 527.39 DOWNSTREAM(FEET) = 526.49 FLOW LENGTH(FEET) = 90.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.49
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.17
PIPE TRAVEL TIME(MIN.) = 0.20 Tc(MIN.) = 7.78
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 215.00 = 7894.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 215.00 TO NODE 220.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 521.91 DOWNSTREAM(FEET) = 519.88 FLOW LENGTH(FEET) = 138.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 12.0 INCH PIPE IS 8.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.50
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.17
PIPE TRAVEL TIME(MIN.) = 0.27 Tc(MIN.) = 8.05
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 220.00 = 8032.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 220.00 TO NODE 220.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 8.05
RAINFALL INTENSITY(INCH/HR) = 6.40
TOTAL STREAM AREA(ACRES) = 1.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.17
**************************************************************************** FLOW PROCESS FROM NODE 225.00 TO NODE 230.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .3500
S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 90.00
UPSTREAM ELEVATION(FEET) = 575.94
DOWNSTREAM ELEVATION(FEET) = 536.32
ELEVATION DIFFERENCE(FEET) = 39.62
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.945
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.776
SUBAREA RUNOFF(CFS) = 0.65
TOTAL AREA(ACRES) = 0.24 TOTAL RUNOFF(CFS) = 0.65 **************************************************************************** FLOW PROCESS FROM NODE 230.00 TO NODE 220.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 532.00 DOWNSTREAM(FEET) = 519.88 FLOW LENGTH(FEET) = 42.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 6.0 INCH PIPE IS 1.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 15.29
ESTIMATED PIPE DIAMETER(INCH) = 6.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.65
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 5.99
LONGEST FLOWPATH FROM NODE 225.00 TO NODE 220.00 = 132.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 220.00 TO NODE 220.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.99
RAINFALL INTENSITY(INCH/HR) = 7.74
TOTAL STREAM AREA(ACRES) = 0.24
PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.65
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 5.17 8.05 6.395 1.01
2 0.65 5.99 7.738 0.24

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 4.50 5.99 7.738
2 5.71 8.05 6.395
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 5.71 Tc(MIN.) = 8.05
TOTAL AREA(ACRES) = 1.2
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 220.00 = 8032.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 220.00 TO NODE 235.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 519.88 DOWNSTREAM(FEET) = 517.05 FLOW LENGTH(FEET) = 193.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 12.0 INCH PIPE IS 9.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.57
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.71
PIPE TRAVEL TIME(MIN.) = 0.38 Tc(MIN.) = 8.42
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 235.00 = 8225.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 240.00 TO NODE 245.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .7900
S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 82.00
UPSTREAM ELEVATION(FEET) = 532.03
DOWNSTREAM ELEVATION(FEET) = 524.56
ELEVATION DIFFERENCE(FEET) = 7.47
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 2.420
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.

SUBAREA RUNOFF(CFS) = 0.27
TOTAL AREA(ACRES) = 0.04 TOTAL RUNOFF(CFS) = 0.27 **************************************************************************** FLOW PROCESS FROM NODE 240.00 TO NODE 245.00 IS CODE = 22 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .7900
S.C.S. CURVE NUMBER (AMC II) = 0
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
SUBAREA RUNOFF(CFS) = 0.27
TOTAL AREA(ACRES) = 0.04 TOTAL RUNOFF(CFS) = 0.27 **************************************************************************** FLOW PROCESS FROM NODE 245.00 TO NODE 250.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 524.56 DOWNSTREAM(FEET) = 494.20 CHANNEL LENGTH THRU SUBAREA(FEET) = 349.00 CHANNEL SLOPE = 0.0870 CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.013 MAXIMUM DEPTH(FEET) = 1.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.617
*USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .7900
S.C.S. CURVE NUMBER (AMC II) = 0
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.37 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 5.11 AVERAGE FLOW DEPTH(FEET) = 0.09 TRAVEL TIME(MIN.) = 1.14 Tc(MIN.) = 6.14
SUBAREA AREA(ACRES) = 1.03 SUBAREA RUNOFF(CFS) = 6.20 AREA-AVERAGE RUNOFF COEFFICIENT = 0.790
TOTAL AREA(ACRES) = 1.1 PEAK FLOW RATE(CFS) = 6.44 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.12 FLOW VELOCITY(FEET/SEC.) = 6.03 LONGEST FLOWPATH FROM NODE 240.00 TO NODE 250.00 = 750349.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 250.00 TO NODE 255.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 491.45 DOWNSTREAM(FEET) = 491.04 FLOW LENGTH(FEET) = 41.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 15.0 INCH PIPE IS 9.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.86
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.44
PIPE TRAVEL TIME(MIN.) = 0.09 Tc(MIN.) = 6.22
LONGEST FLOWPATH FROM NODE 240.00 TO NODE 255.00 = 750390.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 255.00 TO NODE 260.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 488.50 DOWNSTREAM(FEET) = 486.47 FLOW LENGTH(FEET) = 39.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 12.0 INCH PIPE IS 6.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 14.70
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.44
PIPE TRAVEL TIME(MIN.) = 0.04 Tc(MIN.) = 6.27
LONGEST FLOWPATH FROM NODE 240.00 TO NODE 260.00 = 750429.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 265.00 TO NODE 270.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .5700
S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00
UPSTREAM ELEVATION(FEET) = 531.96
DOWNSTREAM ELEVATION(FEET) = 518.31
ELEVATION DIFFERENCE(FEET) = 13.65
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 4.428
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.

SUBAREA RUNOFF(CFS) = 0.74
TOTAL AREA(ACRES) = 0.15 TOTAL RUNOFF(CFS) = 0.74 **************************************************************************** FLOW PROCESS FROM NODE 265.00 TO NODE 270.00 IS CODE = 22 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .5700
S.C.S. CURVE NUMBER (AMC II) = 0
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
SUBAREA RUNOFF(CFS) = 0.74
TOTAL AREA(ACRES) = 0.15 TOTAL RUNOFF(CFS) = 0.74 **************************************************************************** FLOW PROCESS FROM NODE 270.00 TO NODE 275.00 IS CODE = 51 ---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 518.31 DOWNSTREAM(FEET) = 494.55 CHANNEL LENGTH THRU SUBAREA(FEET) = 276.00 CHANNEL SLOPE = 0.0861 CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.013 MAXIMUM DEPTH(FEET) = 1.00 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.709
*USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .5700
S.C.S. CURVE NUMBER (AMC II) = 0
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.86 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 4.49 AVERAGE FLOW DEPTH(FEET) = 0.07 TRAVEL TIME(MIN.) = 1.02 Tc(MIN.) = 6.02
SUBAREA AREA(ACRES) = 0.51 SUBAREA RUNOFF(CFS) = 2.24 AREA-AVERAGE RUNOFF COEFFICIENT = 0.570
TOTAL AREA(ACRES) = 0.7 PEAK FLOW RATE(CFS) = 2.90 END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.09 FLOW VELOCITY(FEET/SEC.) = 4.55 LONGEST FLOWPATH FROM NODE 265.00 TO NODE 275.00 = ********** FEET. **************************************************************************** FLOW PROCESS FROM NODE 280.00 TO NODE 285.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 0
INITIAL SUBAREA FLOW-LENGTH(FEET) = 37.00
UPSTREAM ELEVATION(FEET) = 531.96
DOWNSTREAM ELEVATION(FEET) = 527.86
ELEVATION DIFFERENCE(FEET) = 4.10
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 4.066
WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.

SUBAREA RUNOFF(CFS) = 0.16
TOTAL AREA(ACRES) = 0.06 TOTAL RUNOFF(CFS) = 0.16 **************************************************************************** FLOW PROCESS FROM NODE 280.00 TO NODE 285.00 IS CODE = 22 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

USER-SPECIFIED RUNOFF COEFFICIENT = .3000
S.C.S. CURVE NUMBER (AMC II) = 0
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.695
SUBAREA RUNOFF(CFS) = 0.16
TOTAL AREA(ACRES) = 0.06 TOTAL RUNOFF(CFS) = 0.16 ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 0.1 TC(MIN.) = 5.00 PEAK FLOW RATE(CFS) = 0.16
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

3 .3
Det
ention
Analys
is

(10
0 -
Year Event)

The
und
e
rground sto
rm wate
r
s
torage facilities
(BMP
s)
prov
ide

hydro
mo
dificati
on
manageme
n
t

fl
ow control
a
nd mitigation of the 100
-
year storm
event peak flow rate. The
100
-
year st
orm event
detention a
nalysi
s
was per
formed

using
HydroCA
D Stor
mwater Modeling
softwa
r
e
.

The inflow runo
ff hydrograph
s

to the

BMP
s were

modeled u
si
ng RatHy
dro which i
s

a
R
ational Met
h
od Design Storm Hydrograph software
that creates a hydrograph using the
re
sults of the Rational

Metho
d
calcula
tions.

HydroCAD

has

the a
bility to
route the 10
0 -
year 6
-
hour storm

event inflow hydrogr
aph
through

the
BMPs
.

B
ased on

the
BMP

cro
ss sectional
geometry
,

stage storag
e and outlet st
ructur
e data
, HydroCAD
calcul
at
e
s

the de
taine
d

peak flow
rate and d
et
ained t
ime to

peak.

Each
underg
round sto
rm wate
r
s
tor
a
ge
facility

has a
low
-
flow orifice to c
ompl
y with
H
MP
requi
re
ments an
d an overflo
w weir for larger storm events
.

Refer to
the plans

for

facility

details
.

The proposed BMP at the north
end of the
project site

wil
l

discharge via proposed st
or
m drain

to
the

east and into the existing public
st
or
m dr
ain sys
tem withi
n
Las F
l
ore
s D
rive
.

The
proposed
BMP at the south end of the project site

will discharge
via proposed storm drain
pipe
to the south
and into the existing

public storm drain system within South Santa Fe Drive.

For the
propo
sed detained

hyd
rologic

analysis
,
the e
ffe
cts

of the detention provided by the
two
(2)

undergrou
n
d
s
to
rage fa
ci
lit
ies

were incorporated into the AES analysis. This

w
as
done
by
ins
e
rting

t
he results fro
m
the
HydroCAD

analysis, de
ta
ined pe
ak flow rate and det
ained

time
to
p
eak
, in
to the

pr
op
osed u
ndetaine
d condition AES model to create the proposed detain
ed
condition

model.

Refer
to
Section 3.4

for the

detained AES ou
tp
ut.

B
ased on
t
he resu
lts of the

Hyd
roCAD

analysis
,

mitigation
fo
r the
1 00
-
year storm event
peak
flow r
ate

is
prov
ided
.

R
ef
er

to Appendix
B

for the
HydroCAD

detention detail
ed output
.

3.4 P
ropo
s
ed Deta
ined
Condition Hydrologic Model Output (100
-
Year Event)

____________________________________________________________________________ ****************************************************************************

PASCO LARET SUITER & ASSOCIATES

27127 CALLE ARROYO, SUITE 1904

SAN JUAN CAPISTRANO, CA 92675

ph 949.661.6695

plsaengineering.com
************************** DESCRIPTION OF STUDY ************************** * 3527 SOUTH SANTA FE * * PROPOSED CONDITION DETAINED * * 100-YR * ************************************************************************** FILE NAME: 100PSTD.DAT
TIME/DATE OF STUDY: 11:06 03/02/2022
---------------------------------------------------------------------------- USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
---------------------------------------------------------------------------- 2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.300
SPECIFIED MINIMUM PIPE SIZE(INCH) = 4.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

TC(MIN) = 55.68 RAIN INTENSITY(INCH/HOUR) = 1.84
TOTAL AREA(ACRES) = 1.01 TOTAL RUNOFF(CFS) = 0.30 **************************************************************************** FLOW PROCESS FROM NODE 215.00 TO NODE 220.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 521.91 DOWNSTREAM(FEET) = 519.88 FLOW LENGTH(FEET) = 138.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 6.0 INCH PIPE IS 2.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.26
ESTIMATED PIPE DIAMETER(INCH) = 6.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.30
PIPE TRAVEL TIME(MIN.) = 0.54 Tc(MIN.) = 56.22
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 220.00 = 8032.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 220.00 TO NODE 220.00 IS CODE = 1 ---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 56.22
RAINFALL INTENSITY(INCH/HR) = 1.83
TOTAL STREAM AREA(ACRES) = 1.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.30
**************************************************************************** FLOW PROCESS FROM NODE 225.00 TO NODE 230.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 0.69 5.99 7.738
2 0.45 56.22 1.826
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 0.69 Tc(MIN.) = 5.99
TOTAL AREA(ACRES) = 1.2
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 220.00 = 8032.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 220.00 TO NODE 235.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 519.88 DOWNSTREAM(FEET) = 517.05 FLOW LENGTH(FEET) = 193.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 6.0 INCH PIPE IS 3.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.19
ESTIMATED PIPE DIAMETER(INCH) = 6.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.69
PIPE TRAVEL TIME(MIN.) = 0.62 Tc(MIN.) = 6.61
LONGEST FLOWPATH FROM NODE 200.00 TO NODE 235.00 = 8225.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 240.00 TO NODE 245.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

TC(MIN) = 8.92 RAIN INTENSITY(INCH/HOUR) = 5.99
TOTAL AREA(ACRES) = 1.07 TOTAL RUNOFF(CFS) = 4.02 **************************************************************************** FLOW PROCESS FROM NODE 255.00 TO NODE 260.00 IS CODE = 31 ---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 488.50 DOWNSTREAM(FEET) = 486.47 FLOW LENGTH(FEET) = 39.00 MANNING'S N = 0.009
DEPTH OF FLOW IN 9.0 INCH PIPE IS 6.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 12.94
ESTIMATED PIPE DIAMETER(INCH) = 9.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 4.02
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 8.97
LONGEST FLOWPATH FROM NODE 240.00 TO NODE 260.00 = 750429.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 265.00 TO NODE 270.00 IS CODE = 21 ---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================ *USER SPECIFIED(SUBAREA):

END OF RATIONAL METHOD ANALYSIS

3.5 Hydromodification
Management

To satisfy the requireme
nt
s
o
f the
MS4 P
e
rmit, a

hydrom
odifi
cation

man
agement

strat
e
gy

h
as
been develo
ped for the project based on the F
inal Hydromodif
ic
atio
n Manage
ment Plan dated
March 2011, (Final HMP).

A continuous simulation model,
the Environmental
Protection Agency
(EPA) S
to
rm

Water
Manag
e
ment Mo
del (SW
MM) v
ersion

5.1 , was s
electe
d

t
o
size mitigatio
n
measures. The SWMM model is cap
able of modelin
g
hydr
omodific
ation management facilities
to mitigate the effects of increased runoff from the post -
deve
lopment conditions

and us
e
ch
a
nges t
hat m
a
y cause

negati
ve im
pacts
(i.e
. erosi
on) to

do
wn
stream channel
s.

For

HMP
calculations refer to
the report titl
ed

“Priority D
evelopment Project

(PDP)

Storm Water Quality
Mana
gement Plan

(SWQMP)

for
San Marcos Residences
” dated
March

2021
,
, prepared by
Pasco
L
ar
e
t
Suite
r & As
socia
tes
.

3.6 S
tor
m

Wate
r
Po
llutant Contro
l

To meet the requ
irements of the

MS4

Permit
, th
e

M
o
dular
We
tl
and
s

Systems are

designed to
treat onsite
storm water
pollutants
f
or the

24 -
hour, 85
th

percentile s
t
or
m e
ven
t
.

For

detailed
pollu
tant c
o
n
trol ca
lculations
refe
r to t
h
e rep
ort
titl
ed “
“Priority Development Project

(PDP)

Storm Water Quality Man
a
gement Plan

(SWQMP)

for
San Marcos Residences
” dated
March

2021
,
,
pre
p
ared by

Pasco Laret Suiter & Associates.

APPEND
IX

Hydrology
S
uppor
t
Material

San Marcos Residences
PLSA Project No. 3527
3/4/2022
C = 0.9(%Impervious)+Cp(1 - %Impervious)
Soil Type
C
D
Impervious

0.9 0.9
Pervious, Cp

0.3 0.35
E1
53762
C
0 53762
0 0.30
E2
1834
C
0 1834
0 0.30
E3
71987
D
12919
59068

17.9%

0.45 E4
5243
C
0 5243
0 0.30
P1
43998
C
34828
9170

79.2%

0.77 P2
10531
C
829
9702

7.9%

0.35 P3
46587
D
37689
8898

80.9%

0.79 P4
28583
D
11520
17063

40.3%

0.57 P5
2470
C
0 2470

0.0%

0.30 % Impervious
Runoff Coefficient Table
Weighted Runoff
Coefficient, C

PRE-PROJECT CONDITION

POST-PROJECT CONDITION
% Impervious
Weighted Runoff
Coefficient, C
Impervious
Area (sf)
Drainage Basin
ID
Total Area
(sf)
Pervious
Area (sf)
Soil
Type
Drainage Basin
ID
Total Area
(sf)
Soil
Type
Impervious
Area (sf)
Pervious
Area (sf)

United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
San Diego County
Area, California
Natural
Resources
Conservation
Service
July 27, 2021
Preface
Soil surveys contain information that affects land use planning in survey areas.

They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers.

Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment.

Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions.

The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations.

Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951).

Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations.

The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey.

Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.
3 Contents
Preface.................................................................................................................... 2 How Soil Surveys Are Made..................................................................................5 Soil Information for All Uses.................................................................................8 Soil Properties and Qualities................................................................................ 8 Soil Qualities and Features...............................................................................8 Hydrologic Soil Group (2972/2982 South Santa Fe Avenue)........................8 References............................................................................................................13 4 How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity.

Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA.

The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape.

Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units).

Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research.

The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas.

Soil scientists make many field observations in the process of producing a soil map.

The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded.

These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape.

Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties.

While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management.

Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil.

Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date.

After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report
6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately.

Custom Soil Resource Report
7 Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality.

Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil.

Hydrologic Soil Group (2972/2982 South Santa Fe
Avenue)
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 (A/D, B/D, and C/D). 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.
8 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 (A/D, 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.

Custom Soil Resource Report
9 10
Custom Soil Resource Report
Map—Hydrologic Soil Group (2972/2982 South Santa Fe Avenue) 3668700 3668720 3668740 3668760 3668780 3668800 3668820 3668840 3668860 3668880 3668900 3668700 3668720 3668740 3668760 3668780 3668800 3668820 3668840 3668860 3668880 3668900 481290 481310 481330 481350 481370 481390 481410 481430 481290 481310 481330 481350 481370 481390 481410 481430 33° 9' 31'' N
117° 12' 2'' W
33° 9' 31'' N
117° 11' 56'' W
33° 9' 24'' N
117° 12' 2'' W
33° 9' 24'' N
117° 11' 56'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 50 100 200 300
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,060 if printed on A portrait (8.5" x 11") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map
measurements.

Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 15, May 27, 2020
Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Jan 24, 2020—Feb 12, 2020
The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Custom Soil Resource Report
11 Table—Hydrologic Soil Group (2972/2982 South Santa Fe Avenue)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI DaD Diablo clay, 9 to 15
percent slopes, warm
MAAT
C 1.7 72.6%
HrC Huerhuero loam, 2 to 9
percent slopes
D 0.6 27.4%
Totals for Area of Interest 2.3 100.0%
Rating Options—Hydrologic Soil Group (2972/2982 South Santa Fe Avenue)
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
12 References
American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition.

American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00.

Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31.

Federal Register. July 13, 1994. Changes in hydric soils of the United States.

Federal Register. September 18, 2002. Hydric soils of the United States.

Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States.

National Research Council. 1995. Wetlands: Characteristics and boundaries.

Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.

U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section.

United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1.

United States Department of Agriculture, Natural Resources Conservation Service.

National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.

National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 13 United States Department of Agriculture, Natural Resources Conservation Service.

National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report
14 APPENDIX B

D
ete
n
tion S
u
pport Mat
erial

1L
Inflow to Tank-1 Upper
2L
Inflow to Tank-2 Lower
6P
Tank-1 Upper
8P
Tank-2 Lower
Routing Diagram for 3527
Prepared by Pasco Laret Suiter & Associates, Printed 3/2/2022 HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Subcat
Reach
Pond
Link
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 2 ends

5.17 cfs
@

4.13 hrs
, Volume=

0.216 af
Primary
=

5.17 cfs
@

4.13 hrs
, Volume=

0.216 af
, Atten= 0%
, Lag= 0.0 min
Routed to Pond 6P : Tank-1 Upper
Primary outflow = Inflow, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs DISCHARGE Imported from Tank-1 Upper RatHydro adj.csv
Link 1L: Inflow to Tank-1 Upper
Inflow
Primary
Hydrograph
Time (hours)
95 90
85 80
75 70
65 60
55 50
45 40
35 30
25 20
15 10
5 0
Flow (cfs)
5 4
3 2
1 0

DISCHARGE
Imported from
Tank-1 Upper RatHydro adj.csv

5.17 cfs

5.17 cfs
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 4 ends

5.17 cfs
@

4.13 hrs
, Volume=

0.216 af
Outflow
=

0.30 cfs
@

4.93 hrs
, Volume=

0.214 af
, Atten= 94%
, Lag= 47.9 min
Primary
=

0.30 cfs
@

4.93 hrs
, Volume=

0.214 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 105.13'
@ 4.93 hrs
Surf.Area= 1,600 sf
Storage= 7,805 cf
Plug-Flow detention time=
1,616.3 min calculated for 0.214 af (99% of inflow)
Center-of-Mass det. time=
1,615.9 min ( 1,828.4 - 212.5 )
Volume
Invert
Avail.Storage
Storage Description
#1
100.00'
8,482 cf
Tank-1 Upper (Conic)
Listed below
Elevation
Surf.Area
Voids
Inc.Store
Cum.Store
Wet.Area
(feet)
(sq-ft)
(%)
(cubic-feet)
(cubic-feet)
(sq-ft)
100.00
1,600

0.0 0
0 1,600
101.00
1,600

95.0 1,520
1,520
1,742
102.00
1,600

95.0 1,520
3,040
1,884
103.00
1,600

95.0 1,520
4,560
2,025
104.00
1,600

95.0 1,520
6,080
2,167
105.00
1,600

95.0 1,520
7,600
2,309
105.08
1,600

95.0 122
7,722
2,320
105.58
1,600

95.0 760
8,482
2,391
Device
Routing
Invert
Outlet Devices
#1
Primary
100.00'

12.00" Round Culvert
L=
100.0'

RCP,
groove
end
projecting,

Ke=

0.200

Inlet
/
Outlet
Invert=
100.00'
/

99.00'

0.0100
'/'

Cc=

0.900

0.013,

Flow
Area=

0.79 sf

#2
Device 1
100.00'

0.90" Vert. Orifice
C= 0.600
Limited to weir flow at low heads
#3
Device 1
105.08'
Custom Weir, Cv= 2.62 (C= 3.28)
Head
(feet)

0.00 0.50

0.50 Width
(feet)

6.00 6.00

0.00 Primary OutFlow
Max=0.30 cfs
@ 4.93 hrs
HW=105.13'
(Free Discharge)
1=Culvert
(Passes 0.30 cfs of 6.86 cfs potential flow)
2=Orifice
(Orifice Controls 0.05 cfs @ 10.87 fps)
3=Custom Weir
(Weir Controls 0.25 cfs @ 0.77 fps)
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 5 ends

HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Pond 6P: Tank-1 Upper
Inflow
Primary
Hydrograph
Time (hours)
95 90
85 80
75 70
65 60
55 50
45 40
35 30
25 20
15 10
5 0
Flow (cfs)
5 4
3 2
1 0
Peak Elev=105.13'
Storage=7,805 cf

5.17 cfs

0.30 cfs
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 3 ends

6.44 cfs
@

4.10 hrs
, Volume=

0.233 af
Primary
=

6.44 cfs
@

4.10 hrs
, Volume=

0.233 af
, Atten= 0%
, Lag= 0.0 min
Routed to Pond 8P : Tank-2 Lower
Primary outflow = Inflow, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs DISCHARGE Imported from Tank-2 Lower RatHydro.csv
Link 2L: Inflow to Tank-2 Lower
Inflow
Primary
Hydrograph
Time (hours)
95 90
85 80
75 70
65 60
55 50
45 40
35 30
25 20
15 10
5 0
Flow (cfs)
7 6
5 4
3 2
1 0

DISCHARGE
Imported from
Tank-2 Lower RatHydro.csv

6.44 cfs

6.44 cfs
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 6 ends

6.44 cfs
@

4.10 hrs
, Volume=

0.233 af
Outflow
=

4.02 cfs
@

4.14 hrs
, Volume=

0.231 af
, Atten= 38%
, Lag= 2.7 min
Primary
=

4.02 cfs
@

4.14 hrs
, Volume=

0.231 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 103.35'
@ 4.14 hrs
Surf.Area= 2,100 sf
Storage= 6,686 cf
Plug-Flow detention time=
1,202.2 min calculated for 0.231 af (99% of inflow)
Center-of-Mass det. time=
1,201.2 min ( 1,413.6 - 212.4 )
Volume
Invert
Avail.Storage
Storage Description
#1
100.00'
7,062 cf
Tank-2 Lower (Conic)
Listed below
Elevation
Surf.Area
Voids
Inc.Store
Cum.Store
Wet.Area
(feet)
(sq-ft)
(%)
(cubic-feet)
(cubic-feet)
(sq-ft)
100.00
2,100

0.0 0
0 2,100
101.00
2,100

95.0 1,995
1,995
2,262
102.00
2,100

95.0 1,995
3,990
2,425
103.00
2,100

95.0 1,995
5,985
2,587
103.04
2,100

95.0 80
6,065
2,594
103.54
2,100

95.0 998
7,062
2,675
Device
Routing
Invert
Outlet Devices
#1
Primary
100.00'

12.00" Round Culvert
L=
100.0'

RCP,
groove
end
projecting,

Ke=

0.200

Inlet
/
Outlet
Invert=
100.00'
/

99.00'

0.0100
'/'

Cc=

0.900

0.013,

Flow
Area=

0.79 sf

#2
Device 1
100.00'

0.90" Vert. Orifice
C= 0.600
Limited to weir flow at low heads
#3
Device 1
103.04'
Custom Weir, Cv= 2.62 (C= 3.28)
Head
(feet)

0.00 0.50

0.50 Width
(feet)

7.00 7.00

0.00 Primary OutFlow
Max=3.99 cfs
@ 4.14 hrs
HW=103.35'
(Free Discharge)
1=Culvert
(Passes 3.99 cfs of 5.54 cfs potential flow)
2=Orifice
(Orifice Controls 0.04 cfs @ 8.76 fps)
3=Custom Weir
(Weir Controls 3.95 cfs @ 1.82 fps)
3527
Printed 3/2/2022
Prepared by Pasco Laret Suiter & Associates

Page 7 ends

HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Pond 8P: Tank-2 Lower
Inflow
Primary
Hydrograph
Time (hours)
95 90
85 80
75 70
65 60
55 50
45 40
35 30
25 20
15 10
5 0
Flow (cfs)
7 6
5 4
3 2
1 0
Peak Elev=103.35'
Storage=6,686 cf

6.44 cfs

4.02 cfs

APPE
NDIX
C

Existing and Propose
d

Hydrology Maps

San Marcos City CouncilFebruary 28, 2023

San Marcos City Council
February 28, 2023