32891 (2)���- � 1111111 11111 - 11111111 ""1
�- 170 1IIIIIIIIIIIIII �
I bBZ�
r- i..l III Eille i.il..j.I.`_' -1
� £0
J=
n'
IN THE CITY OF LA QUINTA, CALIFORNIA
HYDROLOGY & HYDRAULICS REPORT
FOR PARCEL MAP 32891 ALSO
INCLUDING 27 OF TRACT 28470 -1
IN THE NE 1/4 OF SECTION 7, T6S, R7E, SBM
EISENHOWER DRIVE
AVENUE 50
CALLE TAMPICO
Z.
0
Z
� 3
AVENUE 52
TRADITION TRAIL
A
ON ITE
, to
4�00
O�oO�
0
VICINITY MAP
NM
f-
Z
R
C!Ssl 70-080 CALLE AMIGO, SUITE 101
UwC!NGINEERING LA QUINTA, CA. 92253
(760) 771 -9993 OFFICE
N (760) 771 -9998 FAX
CIVIL AND STRUCTURAL ENGINEERING - PLANNING - SURVEYING
�RpFESS /pN
\ AR Syq�y �yc,
W No. 47834 = m
a PREPARED UNDER THE DATE CO Z",biz
Exp. 12/31/08 DIRECT SUPERVISION OF:
�� OF ray \F ESSI SHAHANDEH - RCE 47834 - EXPIRES 12 -31 -08
Lot 27 -30 and Parcel 1 Traditions Hydrology
Summary
This report and attached calculations and exhibits are prepared to address drainage and
runoff issues concerning the development for Lot 27 of Tract Map 28470 -1, and Parcel 1
of Parcel Map 32891. Copies of these maps are included in the back of this report.
These issues must be addressed prior to proceeding with construction of residential
dwellings on these parcels. This report is prepared to support the design of
improvements to be constructed to mitigate these hazards.
Site Observations
The existing building pads are comprised of engineered fill against a rocky mountainous
embankment to the east. The proposed building pad on Parcel 1 will, be constructed in
much he same manner. The primary concern for storm water runoff is not the Pads
themselves, but the mountain areas behind the pads. These areas are very rocky,
consisting primarily of decomposed granite and boulders.
An existing 18" PVC pipe for which no construction drawings can be located is shown on
the proposed Storm Drain Improvement Plans. This pipe conveys runoff from the south
side of Lot 29 into the street. Heavy debris flows from Lots 28 and 29 are reported to
adversely affect Lot 34 across the street. The recommendation for improvement will
include mitigating this current problem by removing this pipe when the mountain channel
is constructed.
Both the Engineer of Record and City Engineer have observed that the Original Rough
Grading Plan for the Subdivision called for a drainage channel along the back of 29 and
30 to convey mountainside runoff to the golf course basins. Because of the Adjacent
compatible grades of Lots 28 and 29, the contiguous ownership of these lots, and the lack
of cooperation of the owner or Lot 27 in improving the drainage facilities, it is proposed
to also convey the runoff from Lot 28 through the same channel, so that Drainage Area
`A' as shown on the separate hydrology covering those mountainous areas tributary to
Lots 28, 29 and 30.
Parcel 1, being newly created, is conditioned to provide storm drain facilities for
mountainside runoff tributary to its proposed location. Since the construction of Lot 33
blocked the proposed channel swale on the original rough grading plan, the only viable
option is to drain onto Peerless Place at the highpoint located just north of the southerly
lot line of Lot 27. There it will drain northerly along the easterly portion of the street
section to an existing catch basin near the apex of the curve as it turns west and from
there onto the Golf Course Lake.
The Geotechnical Study reports two specific hazards from the Mountainous Terrain. The
first is significant storm water runoff and erosion debris to the lots, and the second is rock
fall potential. Both of these items must be mitigated to make the Building Pads safe for
construction of residences. A Rock Fall Study has been prepared, and recommends a
basin be dug at the toe of slope with a 3' high impact wall for large boulder impacts. To
address the runoff and debris problems, it is proposed to also�use this structure for storm
water detention. The 3' retaining wall will create the basis for a concrete channel on the
back of the lots to convey drainage from the mountains away from the pads and to the
golf course lakes. Further, this design will eliminate the existing 18" pipe from Lot 29 to
the street, eliminating the existing problem with debris and heavy storm flows.
Site History
The Overall Hydrology for Tract 28470 -1 included all areas, including these lots. There
are three sub -areas that are addressed in the Study. Some summary of the
recommendations of the original report and a commentary on the actual current field
observed conditions follow to help the reviewer to readily understand the drainage issues,
and understand why Essi Engineering Inc. has proposed to handle the mountainside
runoff as proposed.
The actual Pads themselves are included in Sub -area "R22" of the original study, which
' is designed to sheet flow to Peerless Place, thence down the emergency access drive and
to Basin 5. This situation is typical design for the subdivision. The Pads will be
improved with area drains and bubble boxes, which will eliminate any existing erosion
' issues on the pads themselves, and continue to discharge to Peerless Place. Therefore,
this area has not been included in the study.
' The mountainous areas immediately behind the lots are part of Sub -area "012" in the
initial study. This area was originally designed to drain to a graded swale channel at the
toe of the slope. This design feature is clearly indicated in the routing of the Hydrology
in the Report, on the Offsite Hydrology Map (Included) and on the original Rough
Grading Plan. However, the improvements were not constructed in this fashion. Field
observations reveal the channel is not graded. Grading has not been performed in a
' fashion that would allow a channel to be constructed and interconnected. No easements
exist to install any such channel, and now that lots have been sold, property owner
cooperation to record them is difficult to obtain.
Therefore, these mountainous areas which are tributary to all these lots are the greatest
cause of concern. Further complicating the problem, the topography used in the original
study is incomplete. The Master Hydrology Map shows contours for these Mountainous
areas only up to an elevation of 200 feet. The Offsite Hydrology Map used a USGS
Quad Map that clearly shows the ridge line in these areas is further east, and extends to
an elevation of over 400 feet. For calculations to be accurate, the values used for area
and slope must extend all the way to the ridge line. Since the topography is incomplete,
and the areas in error on the October 1996 Hydrology Study and Map, USGS quad sheets
and shadow analysis on aerial photographs has been used to identify the ridge and its
elevations, and used to augment the existing DTM model, for the purpose of modeling
the runoff. RCFCD Manual Plate E -1.1 Sheet 1 of 6, A.1 states that a USGS quadrangle
is an acceptable topography map to model the runoff from, so we have used this option
instead of the more costly option of a new aerial survey. Since the original, and correctly
delineated Offsite Areas were prepared on the Original Offsite Hydrology Map for the
entire subdivision, this is the best way to correctly model the Site for comparison to the
existing prepared studies as well.
Rerunning the calculations with the correct tributary areas and correct runoff coefficients
yields significantly larger runoff and storage requirements than were previously
anticipated. Our goal then is to prepare the best possible mitigation plan for the existing
conditions without severely limiting the building envelope for the already permitted
residential land use of Lots 27 and Parcel 1.
The reviewer should thoroughly study the original Offsite Hydrology Map, Master
Hydrology Map, October 1996 TKC Hydrology Report and Calculations for Traditions
Country Club, and the Original Grading and Street Improvement Plans prepared by TKC
when reviewing the findings of this report. Copies of all of these documents with
comments are being submitted with this report, and all of these records are incorporated
by reference.
Riverside County Hydrolou Manual of 1978 —
Soils Type:
The Hydrologic Soils Type per the Riverside County Hydrology Manual is
"Group D"
Quotation from the RCFCD Manual Page C -2: "Group D — High runoff potential.
Soils having very slow infiltration rates when thoroughly wetted and consisting
chiefly of clay soils with a high swelling potential, soils with a permanent high
water table, soils with a clay pan or clay layer at or near the surface, and shallow
soils over nearly impervious material. These Soils have a very slow rate of Water
Transmission."
Soil Cover Type:
The soil cover is poor, as with most desert mountainous areas, there is little to no
plant coverage to protect the ground from erosion and absorb runoff.
Quotation from RCFCD Manual Page C -3: "Poor — Heavily grazed or regularly
burned areas. Less than 50% of the ground surface is protected by plant cover or
brush and tree canopy."
AMC — Antecedent Moisture Condition
An AMC number of AMC II has been used for this property.
RCFCD Manual Quotation of Page C -4: "AMC II — Moderate Runoff Potential,
an intermediate condition." "For the purposes of design hydrology, using district
methods, AMC II should normally be assumed for both the 10 year and 100 year
frequency storm.
Runoff Index Number and Coefficient of Runoff (Rational Method "C" variable):
Per RCFCD Manual Plate D -5.5 Sheet 1 of 2, The runoff index for Soil "Group
D ", Natural Covers, Barren (Rockland, eroded and graded land) is 93. This is
toward the higher end of the table. The runoff coefficient curve for these variable
results in a C value for the Rational Equation of 0.9. However, due to the
disputed nature of the drainage issue, we shall make no adjustments for any losses
in the studies as presented.
Rainfall Data Source:
Included within this report is the rainfall data generated from the National Oceanic and
Atmospheric Administration (NOAA) Atlas 14 Version 4 charts for both 6 Hour 100
Year and 24 Hour 100 Year storms. The city of La Quinta in their Engineering Bulletin
#06 -16 dated 1/29/07 provides for certain datum to be used for a particular area within
the City's limits. Lot 27 and Parcel 1 lay within Zone 4. However, this study is for the
mountainous area above these properties and lay within Zone 3. storm values in this zone
are;
■ 1 hour: 2.20 ", 3 hour: 2.80 ", 6 hour: 3.40" and 24 hour: 4.50"
' All the hydrographs reflect the use of these intensities.
j Tributary Areas Synthetic Unit Hvdroaranh (Short Method):
Watershed B
Area B -1 is tributary to Parcel 1 and consists of 1.14 Acres of Mountainous .
Terrain.
' Area B -2 is tributary to Lot 27 and consists of 2.84 Acres of Mountainous
Terrain.
At the base of the mountain we proposed a detention basin be built using the required
rock -fall wall as an integral part of the basin. The basin shall be constructed to provide a
'
depth of two feet of storage. As the storm progresses, the basin fills to a point that flows
can be captured by a pre -cast concrete catch basin two foot square with a parkway grate.
This grate provides adequate support since it will be out of the traffic areas. Charts
demonstrate that the basin performs under the maximum Qioo at time period 15 of the 3-
'
hour 100 year storm for Lot 27. This is the worst case for all the periods analyzed for any
of the storms for both parcels.
O
FINDINGS AREA B -1:
Area B -1 has the best performance as to storage, providing 8,404 cubic feet. While
smaller than that provided by B -2, its tributary area is much smaller. After careful
analysis of the 3, 6 and 24 hour 100 year storms we find that area B -2 overflows the
detention basin at later points in the storm
Discharge for the 3 -hour, 100 year storm is begins at period 15 and reaches a
maximum of 2.71 c.f.s. at period 16. Each of these periods has is of 10 minutes.
Discharge for the 6 -hour, 100 year storm never occurs. The proposed basin
provides adequate capacity for this storm.
Discharge for the 24 -hour, 100 year storm is begins at period 45 and reaches a
maximum of 0.70 c.f.s. at period 53. Each of these periods is a duration of 15
minutes.
FINDINGS AREA B -2:
After careful analysis of the 3, 6 and 24 hour 100 year storms we find that area B -2
overflows the detention basin at later points in the storm.
Discharge for the 3 -hour, 100 year storm is begins at period 11 and reaches a
maximum of 6.08 c.f.s. at period 15. Each of these periods is a duration of 10
minutes.
Discharge for the 6 -hour, 100 year storm is begins at period 19 and reaches a
maximum of 2.84 c.f.s. at period 22. Each of these periods is a duration of 15
minutes.
Discharge for the 24 -hour, 100 year storm is begins at period 34 and reaches a
maximum of 1.75 c.f.s. at period 53. Each of these periods is a duration of 15
minutes.
Final Recommendations and Observations
The Channel and Rock fall need to be constructed as shown on the prepared Grading
Plans for the lots, and per the structural details and recommendations of the Geotechnical
Report. The Storm Drain improvements should be adequate to convey all tributary
mountainside runoff from Watershed B, provided the structures are constructed per this
analysis.
If the recommendations of this report are followed, and the improvements are constructed
per the Plans prepared by this office, the hazards from storm water runoff will be
mitigated and the existing issues with the debris flow from the parcels to the street will be
eliminated.
1
CM
Essi Shahandeh, Civil Engineer. Date
R. C. E. 47834, Expires 12/31/08
70 -080 Calle Amigo, Suite 101
La Quinta, Ca. 92253
(760)771 -9993 Office — (760)771 -9998 Fax
-1
v°
e
P
3
v°
1
JJ.GJVVV- IV
t C
tij
T •� 4
T •'W.
T
T
a
D li
D
T
V
D
o
N
J
a 1 e
M
P'4 1
T c
V
T -
T
T
J
0
A 1
i
v t
n �
5
o
33.650000 N
IV 33.btlSSS° IN
a � 7
' •"•� ....catty,
fA
BERRIUM
t � �'' 'Csii : :i.:•
�1 �`f�,�i•• .?: ... i) .bt•. w. NN } `'i. :�.'!C•21`•. r.
� �- ice.- ✓� ^��:: - ..t�•
r,. • r L_.
s. • :+i. i ' i:l::: f:i• 1'2':: -• 2272::::; "r7o g
CO :� :<<� «. »:C' 2 :. d•:= ': :.� a: fix;
,.-..o .r.. iii: wt+... -. ii•- tna...' is2Yn_? 'r
` in-w=.; M.:fL•Sit•.
?i:iec:: ;ta - ..;.:» = i:eii= :ii: :i•:::..•wr.:•- ;:2:2: s tti
.......... ........ _ r•' �: r
tj
�.:2,«. •:.:."i'.af : . •i- M•••••:::iF::; I7i.• .p�.�.........: . .., . :a. �=.••.`Y ... a• • : .„,�
i r
:; :::
.%...... 13 i�a •y=s t^
1 •i2• •�» wr•��.t i2�:� wr;2W •M •a:i Z .�2M Y 11i~ `we. V•'�i.:�
UD
i:aT _ Cr wrl :: +:. •f H: • • N.�t_ �.a. rr1 N
_ET ' y+�., •• .•_..� •~ • ~•__, -. JEFFERSON " }. �
'u:.,N........
A=.:•� #.•.fix •: �._ c. !" K.. i: U
33.E6667° N
33.68333° N
m M- M--M- m - m- m -M. m - -! -m- m m M-- m m m. m - M
�A
•
v
o n
< JP
D C)
L
D_
r
m
O
i
v
N
O
ft
RUNOFF COEFFICIENTS FOR AI INDEX NO. - 92
IMPERVIOUS I INTENSITY - INCHES /MOUR
PERCENT 4II
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
5.
10.
I5.
20.
25.
30.
35.
40.
45.
50.
55.
60.
65.
70.
75.
80.
85.
90.
95.
100.
.00 .73 .B1 .84 .85 .86 .A7 .A7 .87
.04 .74 .81 .84 .85 .86 .R1 .87 .AB .B8 .88
.09 .75 .82 .84 .86 .86 .87 AT .88 .88 .88
.13 .76 .B2 .85 .A6 .87 .A7 .88 .88 .88 .89
.18 .76 .83 .85 .R6 .87 ,R7 .88 .88 .88 .89
.22 .77 .83 .85 .A6 .87 AT ,68 .88 .88 .89
.27 .78 .A3 .85 .87 .87 .88 ,AA .88 .89 .89
.31 .79 .84 .86 .87 .87 .88 .88 .88 .89 .89
,36 .80 .84 .86 ,A7 .88 .8A ,88 .88 .89 .89
.40 .81 .85 .86 .87 .88 .AR .89 .89 .89 .89
.45 .B2 .85 .R7 .88 .98 ,AA .89 .89 .89 .89
.49 .82 .86 .87 .AA .88 .AA ,A9 .89 .89 .89
.54 .83 ,86 .87 .48 AS .A9 .89 .89 .89 .89
.58 .84 .87 .88 .88 .89 .89 .89 .89 .89 .89
.63 as .87 .88 .A9 .89 .R9 .89 .89 .89 .89
.67 .86 .88 .88 .A9 .89 .89 ,A9 ,A9 .89 .90
.72 .87 .88 .89 .89 .A9 .89 .89 .89 .90 .90
.76 .87 .89 .89 .89 .89 .89 .90 .90 .90 .90
.81 .88 .89 .89 .90 .90 .90 .90 .90 .90 .90
.86 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
,90 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
RUNOFF COEFFICIENTS FOR RI INDEX NO. = 96
1MPERVIOUSI INTENSITY - INCHES/HOUR
PERCENT
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
0.
S.
10.
I5.
20.
25.
30.
35.
40.
45.
50.
55.
60.
6S.
70.
TS.
80.
85.
90.
95.
100.
.00 .81 .85 .87 .88 .88 .8A .89 .89 .89 .89
.04 .81 .85 .87 .88 .88 AS .R9 .89 .89 .89
.09 .82 .86 .87 .88 .88 .89 .89 .89 .89 .89
.13 .82 .86 .87 .88 .88 .89 .89 .89 .89 .89
.18 .83 .86 .87 .88 .88 .89 .89 .89 .89 .89
.22 .83 .86 .R8 .BA .89 .89 .89 .89 .89 .89
.27 .84 .87 .88 .98 .89 .89 .89 .89 .89 .89
.31 .84 .87 .88 .88 .89 .89 .89 .89 .89 .89
.36 .85 .87 .88 .89 .89 .89 .69 .89 .89 .90
.40 .85 .87 .88 .A9 .89 .99 .89 .89 .89 .90
.45 .85 .88 .88 .89 .89 .A9 .89 .89 .90 .90
.49 .86 .88 .89 .89 .89 ,A9 .89 .89 .90 .90
.S4 .86 .88 .89 .A9 .89 .89 .89 .90 .90 .90
.58 .87 ,88 .89 .89 .89 .99 ,90 .90 .90 .90
.63 .87 .89 .89 .89 ..R9 .90 .90 .90 .90 .90
.67 .88 .89 .89 .89 .90 .90 .90 ..90 .90 .90
.72 .88 .89 .89 .90 .90 .90 .90 .90 .90 .90
.76 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.81 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
.86 .90 .90 .90 .90 .90 e.90 .90 .90 .90 .90
,90 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
RUNOFF COEFFICIENTS FOR RI INDEX NO. = 94
IMPERVIOUS INTENSITY - INCHES /HOUR
PERCENT
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5,0 6.0
0.
5.
10.
15.
20.
25.
30.
35.
40.
45.
50.
55.
60.
6S.
70.
T5.
R0.
85.
90.
95.
100.
.00 .77 .83 .85 .A6 .87 .8A .R8 .88 .88 .89
,04 .78 .83 .85 .A7 .87 .RR .88 .88 .89 .89
.09 .78 .84 .96 .87 .87 .88 .88 .88 .89 .89
.13 .79 .84 .86 .87 .87 .88 .88 .88 .89 .89
.18 .80 .84 .86 .97 .88 .AR .98 .89 .89 .89
.22 .80 .85 ,86 .87 AS .88 .88 .89 .89 .89
.27 .81 .85 AT .87 .88 .88 .A9 .89 .89 .89
.31 .81 .85 AT .88 .88 .8A .89 .89 .89 .89
.36 .82 .86 .87 .88 .88 .A9 .89 .89 .89 .89
.40 .83 .86 .87 .88 .88 .A9 .89 .89 .89 .89
.45 .83 .86 .98 .8R .89 .149 .89 .89 .89 .89
.49 .84 .87 .8A .88 .89 .89 .89 .89 .89 .89
.54 .85 .87 .88 .89 .89 .89 .89 .89 .89 .89
.58 .85 .88 .88 .89 .89 ,A9 .89 .99 .89 .90
.63 .86 .88 .A9 .89 .89 .89 .89 .89 .90 .90
.67 .87 .88 .89 .89 .89 ,R9 .89 .90 .90 .90
.72 .87 .89 .89 .R9 .89 .90 .90 .90 .90 .90
.76 .86 .89 .R9 .A9 .90 .90 .90 .90 .90 .90
.81 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.86 .89 .40 .90 .90 .90 .90 .90 .90 .90 .90
.90 .90 .90 .90 ,90 .90 ,90 .90 .90 .90 .90
RUNOFF COEFFICIENTS FOR At INDEX NO. - 98
IMPERVIOUSI INTENSITY - INCHES /HOUR
PERCENT
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
0.
.00
.85
.88
.88
.R9
.89
,A9
.89
.89
.90
.90
S.
.04
.86
.88
.88
.89
.89
.89
.89
.89
.90
.90
10.
.09
.86
.88
.89
,R9
.89
.89
.A9
.89
.90
.90
15.
.13
.86
.88
.89
.A9
.89
.89
.89
.89
.90
.90
20.
.18
.86
.88
.89
.89
.69
.R9
.89
.90
.90
.90
25.
.22
.87
.88
,A9
.R9
.89
,89
.89
.90
.90
.90
30.
.27
.87
.88
.89
.89
.89
.R9
.90
.90
.90
.90
35.
.31
.87
.88
.89
.R9
.89
,A9
.90
.90
.90
.90
40.
.36
.87
.89
.89
.89
.89
.90
.90
.90
.90
.90
45.
.40
.87
.89
.89
.R9
.89
.40
.90
.90
.90
.90
50.
.45
.86
.89
.89
.89
.90
.90
.90
.90
.90
.90
55.
.49
.88
.89
.89
.A9
.90
.90
.90
.90
.90
.90
60.
.54
.88
,89
.89
.90
.90
.90
.90
.90
.90
.90
65.
.58
.88
.89
.89
.90
.90
,90
.90
.90
.90
.90
70.
.63
.89
.89
.90
.90
.90
.90
.90
.90
.90
.90
7S.
.67
.89
.89
.90
.90
.90
.90
.90
.90
.90
.90
80.
.72
.89
.90
.90
.90
.90
.90
.90
.90
.90
.90
85.
.76
.89
.90
.90
.90
.90
.90
.90
.90
.90
.90
90.
.81
.90
.90
.90
.90
.90
.90
.90
.90
.90
.90
95.
.86
.90
.90
.90
.90
.90
.90
.90
.90
.90
.90
100.
.90
.90
.90
.90
.90
.90
.90
.90
.90
.90
.90
r
M
T
�O
RAINFALL
PATTERNS
IN
PERCENT
0C)
CP
3 -HOUR
STORM 6 -HOUR STORM
24 -HOUR
STORM
ERNE
PERIOD
S -MIN
PERI00
10 -MRN
PERIOD
IS -MIN 30 -MIN TIME S -MIN
vERIOD PERIOD PERIOD PERIOD
10 -MIN IS -MIN 30 -MIN TIME
vERIOD PERt00 PERIOD
S -MIN
1IME
IS -MIN
70 -MIN
60 -7IN
TIME
IS -MIN
D
1
PERIOD
PERI00
PERI00
PERIOD
PERIOD
PERIOD
PERIOD
PERIOD
•
` I
2
1.3
1.3
2.6
2.6
3.7 6.5 1 .S
•.B 10.0 2 .6
1.1 1.7 7.6 49
1.2 '1.9 •.3 SO
1.1
1.8
1
.2
.S
1.2
49
2.5
D
v
3
•
1.1
1.5
3.3
7.3
S.l 17.9 3 .6
♦.9 17.•
1.3 2.1 •.B SI
1.9
2
3
.3
.3
.7
.6
1.3
I.B
'SO
SI
2.6
2.8
S
1.5
3.3
• .6
6.6 29.9 5 .6
1•• 2.2 ♦.9 52
1.♦ 2.♦ S.3 53
2.0
2.l
•
5
.•
.7
2.1
52
2.9
6
1.8
3.•
•.♦
7.3 20.3 6 .7
B.♦ 7
I.S 2.♦ S.8 S•
2.1
6
.7
.3
.8
1.0
2.B
2.9
53
5•
3.♦
3.•
8
9
I.B
1.B
♦.2
5.7
.7
9.0 B .)
12.3
1.6 2.• 6.B SS
1.6 2.S 9.0 56
2.2
2.3
7
B
.7
.♦
1.0
!.1
7.8
•.6
55
56
2.3
2.3
10
11
1.5
5.1
9 .7
17.6 10 .)
1.6 2.6 11.6 S7
1.6 2.7 14.• SB
2.•
2.•
9
IO
.♦
l.3
I.S
6.3
57
2.7
12
1.6
1.8
6.•
5.9
16.1 11 .7
4.2 12 .8
1.6 2.8 25.1 S9
1.1 - 3.0 •.♦
2 S
11
.•
.5
1.3
B.2
7.0
SB
S9
2.6
2.6
13
14
2.2
2.2
7.7
B.5
17 .B
1•
1.7 7.2 60
1.6 61
2.6
3.1
12
13
.S
.S
1.6
1.6
7.7
I7.B
60
61
2.5
2.4
IS
16
2.2
2.0
1•.1
1•.1
.8
IS .8
7,6
62
1.8 •.3
67
3.6
3.9
1•
1S
.S
.S
2.0
2.1
ll.•
10.♦
17
2.6
3.B
16 .B
17 .B
1.8 •.7
2.0 S.• 6•
•'2
16
17
.6
2.5
7.0
B,5
63
6♦
1.9
1.9
I8
19
2.7
2.•
2.4
16 .8
19
2.0 6.2 6S
66
2.1
• :7
5.6
1B
.6
.7
3.3
I.•
1.9
- 65
66
.•
20
21
2.7
3.3
.B
20 .B
6.9
11
2.2 7,5 68
19
19
20
.7
.8
3.9
♦.3
1.1
1.2
67
.•
.3
22
23
3.1
2.9
21 .B
22 .8
I.S 10.6
69
2.8 1•.S 70
6
21
22
.6
.7
3.0
♦.0
1.1
I.0
6B
69
.3
.5
24
25
3.0
27 .8
2• .9
3.0 3.♦ 71
3.2 1.0
,5
,3
23
2•
•8
.B
3.8
].S
,9
70
71
.S
.5
26
7.1
♦.2
25 .8
26
72
3.S
3.9
.2
25
.9
S.1
,B
72
73
.•
.♦
27
28
5.0
3.5
.9
27 .9
2B
•.2
26
27
.9
1.0
5.7
6.8
7•
75
••
T
/y
29
30
6.8
7.3
.9
29 .9
•.S
♦.B
28
29
1.0
1.0
•.6
S.3
76
.3
.2
D
31
32
B.2
30 .9
31 .9
5.1
6.7
30
71
I.l
1.2
S.l
•.7
7)
78
.3
••
Z
33
5.9
2.0
32 .9
73 1.0
B.1
10.7
]2
33
1.3
1.5
].8
79
60
.]
.2
Z
3•
1.8
1
7♦ 1.0
35 1.0
2.8
1.1
3•
1.5
.8
.6
BI
82
.3
.]
76
6
76 1.0
S
3S
1.6
1.0
B3
.3
r�7
1
77 1.0
38 1.1
37
1.9
,8
84
5
.2
.3
m
r
1
78
2.0
2.1
,S
:6
•0 1.1
40
2.2
•S
87
.3
♦1 1.2
•2 1.3
•1
•2
1.5
1.5
.6
,g
88
B9
.2
.3
^
.3 1.•
.3
2.0
.5
90
.2
TJ
1.1
♦S 1.5
•5
1.9
•S
92
.2
Z
J
46 1.5
47 1.6
•6
1.9
.•
93
9•
.2
.2
Q
♦B 1.6
47
♦B
1.7
I.B
.♦
.•
96
.2
Z
NOTES:
I. 3 and
6 -hour patterns based on the Indio area thunderstorm of September 24,1939.
2. 24 -hour patterns based on the general storm
of March 2 86 3,1938.
RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL -COVER COMPLEXES FOR PERVIOUS AREAS -AMC II
Cover Type (3)
Quality of
Cover (2)
Soil Group
A
B
C
D
NATURAL COVERS -
Barren
78
86
91
93
(Rockland, eroded and graded land)
Chaparrel, Broadleaf
Poor
53
70
80
85
(Manzonita, ceanothus and scrub oak)
Fair
40
63
75
81
Good
31
57
71
78
Chaparrel, Narrowleaf
Poor
71
82
88
91
(Chamise and redshank)
Fair
55
72
81
86
Grass, Annual or Perennial
Poor
67
78
86
89
Fair
50
69
79
84
Good
38
61
74
80
Meadows or Cienegas
Poor
63
77
85
88
(Areas with seasonally high water table,
Fair
51
70
80
84
principal vegetation is sod forming grass)
Good
30
58
72
78
Open Brush
Poor
62
76
84
88
(Soft wood shrubs - buckwheat, sage, etc.)
Fair
46
66
77
83
Good
41
63
75
81
Woodland
Poor
45
66
77
83
(Coniferous or broadleaf trees predominate.
Fair
36
60
73
79
Canopy density is at least 50 percent)
Good
28
55
70
77
Woodland, Grass
Poor
57
73
82
86
(Coniferous or broadleaf trees with canopy
Fair
44
65
77
82
density from 20 to 50 percent)
Good
33
58
72
79
URBAN COVERS -
Residential or Commercial Landscaping
Good
32
56
69
75
(Lawn, shrubs, etc.)
Turf
Poor
58
74
83
87
(Irrigated and mowed grass)
Fair
44
65
77
82
Good
33
58
72
79
AGRICULTURAL COVERS -
Fallow
76
85
90
92
(Land plowed but not tilled or seeded)
R C F C a W C D RUNOFF INDEX NUMBERS
rIYDROLOGY NIANUAL FOR
PERVIOUS AREAS
PLATE E -6.1 0 of 2)
m
Wqw"
IPrecipitation Frequency Data Server
Page 1 of 3
POINT PRECIPITATION
FREQUENCY ESTIMATES p
FROM NOAA ATLAS 14
California 33.66922 N 116.29036 W 141 feet
from "Precipitation- Frequency Atlas of the United States" NOAA Atlas 14, Volume 1, Version 4
' G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland, 2006
Extracted: Wed May 21 2008
Confidence Limits I- Seasonality [1 Location Maps I!' Other Info. I• GIs data [i M ps I Help I Doc;'I, U.S. Map
Precipitation
Frequency Estimates (inches)
(y ars)
min
[IMIFmll
0.33
non
F11
T21
Ed
(
�
hr 11
h I
d
da
day 11
day
�
d-a�
d
0.34
0.53
0.10
0.15
0.19
0.26
0.32
0.44
0.51
0.68
0.84
0.89
0.91
0.96
1.06
1.13
1.26
1.41
1.59
1.68
1.12
0.14
0.21
0.26
0.36
0.44
0.59
0.69
0.92
1.13
1.21
1.23
1.30
1.44
1.54
1.73
1.93
2.18
2.30
0
0.22
0.34
0.42
0.56
0.70
0.91
1.04
1.37
1.68
1.83
1.84
1.95
2.15
2.31
2.61
2.90
3.27
3.47
7107
0.29
0.45
0.56
0.75
0.93
1.19
1.34
1.73
2.10
2.31
2.31
2.47
2.71
2.92
3.29
3.64
4.10
4.35
25
0.41
0.63
0.78
1.05
1.30
1.62
1.80
2.25
2.70
3.00
3.03
3.24
3.52
3.80
4.26
4.69
5.24
5.58
7107
0.52
0.80
0.99
1.33
1.65
2.01
2.19
2.71
3.19
3.58
3.64
3.88
4.19
4.53
5.05
5.53
6.14
6.55
100
0.65
0.99
1.23
1.66
2.05
2.46
2.64
3.20
3.73
4.19
4.32
4.61
4.92
5.33
5.91
6.43
7.09
7.58
200
0.81
1.23
1.52
2.04
2.53
2.98
3.16
3.75
4.30
4.87
5.07
5.40
5.71
6.19
6.83
7.39
8.08
8.65
F5-0-0-171051
9.11
1.60
1.98
2.67
3.30
3.80
3.96
4.57
5.14
5.85
6.19
6.59
6.87
7.45
8.14
8.75
9.46
10.15
1000
1.27
1.94
2.40
3.23
4.00
4.53
4.66
5.27
5.84
6.66
7.15
7.59
7.83
8.51
9.23
9.85
10.55
11.34
' These precipitation frequency estimates are based on a partial duration sedes. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting forces estimates near zem to appear as zero.
� I
* Upper bound of the 90% confidence interval
Precipitation Frequency Estimates (inches)
ARI ** ❑5 10 15 30 60 120 ]Fhr]F' 3 6 2 24 48 ❑4 ❑7 10 20 30 45 60
(years) min mm mm mm mm mm hr hr hr hr day day day 11 day 11 day 11 day 11 day
�1
0.13
0.20
0.24
0.33
0.40
0.54
0.62 0.83
1.01
1.06
1.06
1.12 1.23
1.31
1.47
1.63
1.83
1.93
�2
0.18
0.27
0.43
0.34
0.53
0.45
0.56
0.74
0.84
1.11
1.36
1.44
1.46
1.52 1.67
1.78
2.01
2.23
2.52
2.65
0
0.28
0.71
0.88
1.12
1.27
1.65
2.01
2.17
2.19
2.28
2.50
2.67
3.02
3.35
3.77
3.99
10
0.37
0.56
0.70
0.94
1.16
1.46
1.63
2.08
2.51
2.74
2.77
2.89
3.14
3.38
EKE
2.32
4.72
5.00
25
0.51
0.78
Efl
1.31
1.62
1.98
2.18
2.72
3.23
3.56
3.60
3.79
4.08
4.39
4.92
5.42
6.04
6.42
50
0.65
0.99
1.23
1.65
2.04
2.45
2.65
3.26
3.83
4.24
4.25
4.56
4.86
5.23
5.84
6.40
7.09
7.55
100
0.81
1.23
1.52
2.05
2.54
2.99
3.20
3.87
4.48
4.98
5.05
5.42
5.74
6.17
6.84
7.47
8.22
8.76
200
0.99
1.51
1.88
2.53
3.13
3.63
3.85
4.54
5.19
5.79
5.95
6.39
6.69
7.21
7.94
8.64
9.41
10.02
500
1.30
1.98
2.41
2.46
2.99
3.31
4.03
4.09
4.99
4.66
5.59
4.86
5.57
6.22
6.99
7.31
7.85
8.12
8.73
9.53
10.31
11.10
11.82
1000
1.59
5.75
6.46
7.13
8.01
8.49
9.11
9.31
10.03
10.88
11.69
12.45
13.28
' - i ne upper Doan or me connoence interval at uu %confidence level is the value which 5% of the simulated quantile values for a given frequency are greater than.
These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
I' The lower bound of the confidence interval at 90% confidence level is the value which 5% of the simulated quantile values for a given frequency are less than.
* Lower bound of the 90% confidence interval
Precipitation Frequency Estimates (inches)
FA _R1 5 10 15 30 60 120 3 6 12 24 48 4 7 10 20 30 45 60
(years) min min min min min min hr hr hr hr hr day day day 11 day day day day
�1
0.08
0.12
0.15
0.21
0.26
0.36
0.42
0.56
0.70
0.74
0.78
0.83
0.92
0.9'7
1.09
1.23
1.37
1.45
2
0.11
0.17
0.21
0.29
0.35
0.49
0.57
0.76
0.94
1.01
1.06
1.12
1.24
1.32
1.48
1.67
1.88
1.98
0 0.18
0.27
0.34
0.45
0.56
0.75
0.86
1.13
1.39
1.52
1.57
1.68
1.84
1.98
2.24
2.51
2.82
2.98
10 JF0 .23
0.36
0.44
0.59
0.74
0.97
1.10
1.42
1.73
1.92
1.98
2.11
2.32
2.50
2.81
3.14
3.52
3.72
F25-1 0.32
0.49
0.61
0.82
1.01
1.30
1.46
1.84
2.20
2.47
2.57
2.75
2.97
3.22
3.61
4.01
4.47
4.74
50 0.40
0.61
0.76
1.02
1.26
1.59
1.75
2.18
2.59
2.92
3.05
3.26
3.50
3.80
4.25
4.71
5.22
5.53
100 0.49
0.75
0.93
1.25
1.54
1.90
2.09
2.55
2.98
3.40
3.58
3.82
4.08
4.43
4.92
5.44
5.99
6.35
200 0.59
0.90
1.12
LE
1.86
2.26
2.46
2.95
3.41
3.92
4.14
4.42
4.67
5.09
5.64
6.18
6.78
7.18
500
0.75
1.14
1.41
1.90
2.35
2.80
2.99
3.52
4.00
4.63
4.96
5.28
5.52
6.01
6.62
7.22
7.84
8.32
1000
0.88
1.34
1.67
2.24
2.78
3.26
3.44
3.99
4.47
5.20
5.63
5.99
6.20
6.78
7.40
8.04
8.65
9.22
I htt : //hdsc.nws.noaa. ov /c i- bin/hdsc/buildout. erl? e= f &units =us &series= d &statename= SOUTHE... 5/21/2008
p g g p h'p P p
' Precipitation Frequency Data Server
These precipitation freque icy estimates are based on a partial duratlon maxima series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
Text versior_ of tables
.^ Partial duration based Point Precipitation Frequency Estimates - Version: 4
33.66922 N 116.29036 W 141 ft
. 1 2 3 4 5 6 7 8 910 20 30 40 50 80100 140 200 300 500 700 1000
Average Recurrence Interval (years)
LJorl Main P1 1 Q: 1 P: A'3 ?PAR
Duration
C
5-min
-_..
48 -hr- 30 -day -r+-
10 -min -a-
3 -hr -«-
4 -day �-
15-min -+-
6 -i-w
7 -uau -»- 60 -day -->«-
30 -min -e-
12 -hr -+-
10 -day -+•-
60 -min -+.-
24 -hr --a-
20 -da
Partial duration based Point Precipitation Frequency Estimates - Version: 4
33.66922 N 116.29036 W 141 ft
Page 2 of 3
Maps -
'' htt : / /hdsc.nws.noaa. ov /c i- bin/hdsc /buildout. erl ?t YP e= f &units =us &series= d &statename= SOUTHE... 5121/2008
C
C C C
G C E
L L
L L L L L
L L
T T T
T
T
a T
T
T T
s
e s
I
e e m
-C s
i i
s s s _c s
i i i i i
s Jr
i 1
m m m
v '0 v
M
'o
m
a
m m
�,
m
a
m n
-a a
y
m
I I N
m m -
C
N m Q
.- cu
.W
m a
I I I
m a u)
1
N
I
m
I I
u; m
I
m
I I
u) o
m
`D a,
Duration
-�
-+ Cu
C7
ID
Wed May 21
13:12:03 2008
Page 2 of 3
Maps -
'' htt : / /hdsc.nws.noaa. ov /c i- bin/hdsc /buildout. erl ?t YP e= f &units =us &series= d &statename= SOUTHE... 5121/2008
Precipitation Frequency Data Server
116.4"W 116.9"W 11r'.2%
Other Maps /Photographs -
Taese maps were produced using a direct map request from the
U.S. Census Bureau Maoing and Cannoraohic Resources
TaepM Server.
Please read disclatmerfor more information.
LEGEND
— State — Connector
- -- County gam, Stream
Indian Resv Military Area
® Lake /Pond /Ocean National Park
— Street am Other Fark
-- Expressway City
— Highway .o C.qunty.., .8 mi
Scale 1:228583 1
*average- -true scale depen s on monitor$ esofution
Page 3 of 3
' View USGS digital orthophoto quadrangle (DOQ) covering this location from TerraServer, USGS Aerial Photograph may also be available
from this site. A DOQ is a computer- generated image of an aerial photograph in which image displacement caused by terrain relief and camera tilts has been removed. It
combines the image characteristics of a photograph with the geometric qualities of a map. Visit the USGS for morn information.
Watershed/Stream Flow Information -
Find the Watershed for this location using the U.S. Environmental Protection Agency's site.
Climate Data Sources -
Precipitation fre ?uency results are based on data from a variety of sources, but largely NCDC. The following links provide general information
about observing sites in the area, regardless of if their data was used in this study. For detailed information about the stations used in this study,
please refer to our documentation.
Using the National Climatic Data Center's (NCDC) station search engine, locate other climate stations within:
+1-30 minutes ) ..,OR 414 J of this location (33.66922/- 116.29036). Digital ASCII data can be obtained directly from NCDC.
Find Natural Re €ources Conservation Service (NRCS) SNOTEL (SNOwpack TELemetry) stations by visiting the
Western ftioral Climate Center's state - specific SNOTEL station maps.
llydrometeorologica Design Studies Center
DOGNOAA/Nationil Weather Service
1325 East -West Higlway
Silver Spring, MD 21910
(301) 713 -1669
Questions ?: HDSC QLesti m5, noaasov
Disclaimer
http: / /hdsc.iiws. noaa. gov /cgi- bin/hdsc /buildout.perl? type =pf& units =us &series= nd &statename= SOUTHE... 5/21/2008
P.O. Box 1504
LA QUINTA, CALIFORNIA 92247 -1504 PUBLIC WORKS /ENGINEERING DEPARTMENT
78 -495 CALLE TAMPICO (760) 777 -7075
LA QUINTA, CALIFORNIA 92253 FAX (760) 777 -7155
ENGINEERING BULLETIN #06 -16
Corrected 1/29/07
TO: A,II Interested Parties
FROM: imothy R. Jonasson, Public Works Director /City Engineer
EFFECTIVE DATE: December 19, 2006
SUBJECT: Hydrology Report with Preliminary Hydraulic Report Criteria for
Storm Drain Systems
This bulletin establishes storm drain study specifications. All hydrology and
preliminary hydraulic reports for the City of La Quinta should follow these criteria.
Hydrology studies for the City of La Quinta shall be performed for projects when
required by the conditions of approval or as requested by the City Engineer.
Reference material used for city plan checking purposes is as follows:
1. Plan Check Checklist
Storm drain plan checks are guided by the documents found in the following
hyperlink:
http://www.la-guinta.org/publicworks/tractl/z onlinelibrary /plancheck checklist %20NEW.htm
2. Archive Plans
Example City plans can be found at the following hyperlink:
http://www.la-guinia.org/plancheck/m—search.asp
A useful method of quickly searching archive plans is to load the plan type and
current year (e.g. 2006) and then search the archive by clicking the GO button.
3. Hydrology Reports
All hydrology reports shall follow the general guidelines set forth by Riverside
County Flood Control (RCFC) and Water Conservation District's Hydrology Manual.
4. Hydraulic Report Guidelines (General)
Hydraulic reports shall follow the guidelines set forth by either Riverside County
Flood Control Hydrology Manual or Federal Highway Administrations FHWA HEC-
22 "Urban Drainage Design Manual," The developer engineer's hydraulic report is
required with the storm drain submittal but can be submitted earlier with the rough
grading submittal. Street plans must have an accompanying hydraulic report. The
hydraulics for the project will be reviewed and approved only with the street plans.
STORMCAD or equivalent commercially available hydraulic programs are acceptable
for hydraulic calculations. Hydraulic program data and resultant calculations must
relate to Riverside County Flood Control Hydrology Manual design guidance.
5. Use of Rational Method (Catch Bas_ in Sizing) and Synthetic Unit Hydrograph
(Retention Sizing)
' For Catch Basin Sizing Only:
• Rational Method may be used for projects with less than 10 acres for
catch basin sizing only. The Rational Method may be utilized to
' determine flow rates generated from each drainage area, to model street
flow capacities and to size catch basins. The Rational Method obtains
flow rates (cfs).
' For Retention Sizing Only:
• Synthetic Unit Hydrograph Analysis (Shortcut Method) should be used
' for projects less than 100 acres and the lag time is less than 7 minutes
(see RCFC Hydro Manual page E- 1.2),. This method results in both flow
rates (cfs) and volumes (cu ft). For smaller projects, either the Rational
' Method or the Synthetic Unit Hydrograph Analysis (Shortcut Method)
may be used for the hydrology report for the project. The Synthetic Unit
' Hydrograph Analysis (Shortcut Method) is required for the hydrology
reports for projects less than 100 acres. As stated in the RCFC & WCD
handbook (Plate E -1.2, item 6) "The three hour storm peaks should
normally compare well with rational peaks ".
• Synthetic Unit Hydrograph Analysis should be used with large sites
' where individual water shed areas . may exceed 100 + acres. This
method results in both flow rates (cfs) and volumes (cu ft).
■ 6. Inlets
The City prefers use of curb opening inlets in most cases. Flow by conditions for
' side curb inlets should attempt to achieve 85% capture efficiency. Inlets (curb
opening (sag or flowby), grates (sag or flowby), combination (sweeper), and
median drop, channels, piping, or hydraulic conduits not found in the Riverside
' County 'Flood Control Manual shall be designed according to the Federal Highway
Administrations FHWA HEC -22 "Urban Drainage Design Manual ". Use of other
jurisdictional catch basin sizing charts is not allowable. Catch basin sizing charts
can have varied conditional assumptions as compared to HEC -22 analysis.
7. Retention Basin Design
Preliminary basin design shall follow these guidelines. The City of La Quinta
Engineering Bulletin 97 -03 has been superseded by this City of La Quinta
Engineering Bulletin 06 -14. Design criteria include:
• Retention basins shall be sized to contain the design storm and all criteria
listed in this Engineering Bulletin 06 -14. For design purposes, the design
storm shall be the 100 -year storm event that produces the most runoff
reaching the retention basin. Runoff /retention calculations shall be prepared
utilizing Riverside County Flood Control and Water Conservation District
Hydrology Manual guidance to calculate the required retention capacity for
each of the following storm events: 1 hour, 3 hour, 6 hour and 24 hour
storms.
• The maximum allowable water depth of a retention basin when the design
storm is contained is five (5) feet. Retention basins deeper than 6 -feet are
not allowed, unless the depth of the basin was clearly specified on a
document that was presented to the Planning Commission and /or City
Council during the public hearing when the project received its entitlement.
• Retention basins deeper than 6 feet are not permitted in un -gated
communities. Further more, retention basins deeper than 6 feet shall have
eight (8) feet wide level terraced benches around the entire perimeter of the
basin located at water surface contours where the water is 5, 10 and 15
feet deep, as applicable. In no event shall the maximum water depth exceed
nineteen (19) feet deep in any location when the 100 -year storm is
contained. Retention basins deeper than 6 feet shall also have a five (5) feet
wide level, terraced bench located one (1) foot above the 100 -year water
surface level around the entire perimeter of the basin. The retention basin
should be capable of percolating the entire 100 -year storm retention capacity
in less than 72 hours.
• One (1) foot of freeboard shall be provided when the 100 year storm is
contained. The one -foot freeboard requirement is a minimum value.
Freeboard is defined as the elevation differential between the 100 -year water
surface elevation and the nearest street flowline elevation.
• The maximum allowable side slope is 3:1.
• A maintenance access ramp with a maximum 15% slope shall be provided
from the nearest street to the retention basin bottom. Signage indicating
not a pedestrian ramp is required. The ramp shall be located at the nearest
street to the retention basin bottom. The ramp width shall be a minimum of
15 feet.
• A nuisance water dissipater shall be installed in the bottom of each retention
basin, pursuant to site specific geotechnical engineering recommendations.
' The nuisance water shall be piped directly to the nuisance water dissipater
from the storm drain inlet in the street.
The retention basin shall be landscaped and properly irrigated.
* Publicly maintained retention basins shall not be fenced or walled
•: All areas of publicly maintained retention basins shall be visible from the
adjacent street.
::, The percolation rate in a retention basin shall be considered zero unless a site
specific percolation test is performed and test results are approved by the
City. The maximum allowable percolation rate is two (2) inches per hour.
An emergency overflow route shall be provided for storm volumes greater
than the, design storm. Overflow to a City arterial street is the preferred
routing except in circumstances where significant grade differentials occur
away from the City street network.
8. Retention Basin Nuisance Water Handling
Drywells for nuisance water dissipation are ,utilized in most retention basins
conditional on the site having an acceptably deep water table. Drywells for
retention basins must penetrate a minimum of 10 ft into suitable permeable strata
and must utilize the Maxwell Plus design or equal. The final depth of the drywell
must be above the top of the water table. Shallow drywells for small nuisance
water volumes may utilize the Maxwell IV design or equal. A geotechnical opinion
stating the allowable and specific casing design of the drywell should be provided
to the City for approval.
0
The use of drywells and sand filters shall be determined by the infiltration testing
(see below). Field experience has shown that areas of homogenous sand deposits
are typically found in north La Quinta. Generally, sand filters can only be used in
areas of homogenous sand deposits, which are typically found in north La Quinta.
Conversely, field experience has shown that historical lake bed areas or equal
lithologies are found in south La Quinta (south of Hwy 111). These historical lake
bed areas ,would most typically obtain low infiltration rate results. Additionally,
shallow silt lenses may be found throughout the City of La Quinta. Silt lenses or
lake bed areas generally preclude natural percolation as well as the use of sand
filters. Sand filters are, in general, being phased out of La Quinta nuisance water
handling systems. If utilized, sand filter designs shall follow the City of La Quinta
Standard 370. Well site blow off retention must be handled within a separate
nuisance water retention system.
W
• Well site retention shall be capable of handling a minimum of 10,000 gallons
per day. CVWD may allow for installation of a nuisance well site blow off
retention basin within the well site perimeter if sufficient area and land
dedication is available. All nuisance water shall be retained on site.
• The filtering system shall be able to contain surges of up to 3 gph /1,000 sq
ft and infiltrate 5 gpd / 1,000 sq ft. The square footage is based. on
landscape area.
• Drywell infiltration rate testing shall be based on the report entitled
"Riverside County Department of Health - Waste Disposal for Homes,
Commercial, and Industry ". This report identifies the drywell test' method
which can be used in any location. Drywells may not be installed beyond a
depth that intersects a water table. The final depth of the drywell must be
above the top of the water table.
Sand filter infiltration rate testing should use field double ring infiltrometer
ASTM D.3385 -88 (sand, lithology) or ASTM D5093 -90 (clay lithology).
Please see the published report and procedure for each ASTM method. City
acceptance of this testing will be based on boring logs showing homogenous
coarse sand or gravel deposits with a continuous depth of 10ft or more
below the bottom of retention basin. If test shows acceptable percolation,
but the borings show non coarse deposits (silts or clay), then drywell use is
recommended.
9. Retention Basin Percolation for Retention Basin Sizing
Percolation testing for retention basin sizing calculations should use field
borings and test with a double ring infiltrometer ASTM D3385 -88 (sand
lithology) or ASTM D5093 -90 (clay lithology) method or U.S. Bureau of
Reclamation Method for Unsaturated Soils above Groundwater for .
verification of percolation.
�. • In cases where double ring infiltrometer testing creates excessive excavation
or safety issues, the U.S. Bureau of Reclamation Method for Unsaturated
Soils above Groundwater should be utilized.
•: The ASTM D3385 -88 (sand lithology) or ASTM D5093 -90 (clay lithology)
methods, properly conducted, are preferred over the U.S. Bureau of
Reclamation Method for Unsaturated Soils above Groundwater testing
method.
'' •: The, top elevation of the ASTM boring test area should represent the
estimated retention basin bottom. The ASTM D5093 -90 test requires a pre-
soak condition for infiltration testing. The ASTM double ring infiltrometer
' test should terminate approximately 1 foot below the estimated basin
bottom. The infiltration test boring utilized for the U.S. Bureau of
Reclamation Method should terminate approximately 3 feet below the
'
estimated basin bottom with a 3 feet of water head test ,performed to
simulate percolation.
'
•. Percolation test results are subject to City Engineer approval. The total
retention basin percolation rate is based on a combination of City data
review of the following:
■ Percolation of 2 inch : per hour may be assumed if ASTM D3385- p y
'
88 (sand lithology) or ASTM D5093 -90 (clay lithology) test
results confirm GREATER THAN 2" per hour percolation and
confirm no clay or silt layer to a depth of 15 ft below the
bottom of the retention basin.
■ If less than 2" per hour percolation is obtained by the ASTM
methods OR U.S. Bureau of Reclamation Method for
Unsaturated Soils above Groundwater, then the finest soil type
found to a depth of 15 ft (continuous sampling) below the
bottom of retention basin will govern the assumed percolation
as follows:
1. Clay /Clayey Soil = 0 in /hr
2. Silt Soil = 0 in /hr
3. Coarser Soil than Silt = a demonstrated weighted
average percolation based on multiple borings and ASTM
D3385 -88 and ASTM D5093 -90 tests
■ Landscape cover type at the retention basin according to the
RCFC Hydrology Manual and Soil Conservation Maps may also
further limit percolation.
10. Retaining Walls within Retention Basins
Retaining walls are discouraged for use in retention basins. If specified, walls
should consist of reinforced concrete or equal as approved by the City Engineer to
specifically prevent undermining of the retaining wall footing during and after (quick
drawdown) large storm events. Use of walls as a top ring of the retention basin is
' prohibited. Retaining walls will require approval from both the Public Works
Department Director /City Engineer and Community Development Department
Director.
11. Retention Basin Width
Retention 'basins shall have a minimum width of 20 feet as measured from the
lowest elevation contour. Previously, retention basin widths were governed by City
' guidance for aspect ratios for basins depths greater than 6 feet.
12. Overflow Routes
' Retention basins should be designed to overflow to City arterial streets or the
adjacent local street as applicable. Historical flow route should be followed and not
changed on a regional perspective but re- grading and import to achieve an
immediate route to the adjacent street should be considered for projects which
concentrate flows to adjacent open land or off -site developments. Overflow routes
shall be designed using an open channel flow (surface flow). Closed conduit
emergency overflow must be approved by the City Engineer.
13., Rainfall Intensity
Rainfall intensity for hydrological report preparation is regionally zoned within the
City pursuant to available NOAA data. A regional rainfall intensity map of the City
should be referenced to 'confirm rainfall amount assumptions provided in the
following table. *The design storm for the City is 100 -year storm (worst case of
24 hour, 6 hour, 3 hour or 1 hour duration). The 500 -year storm is only used to
review for problematic secondary overflows which do not drain to a public arterial
street, creating a trapped water condition.
14. Hydrograph Loss Rates
According to the Riverside County Flood Control Hydrology Manual, the loss rates
generally range from 0.10 to 0.40 in /hr with most falling between 0.20 and 0.25
in /hr. Three and six hour duration storms may use a constant loss rate; however,
the 24 hour duration storm shall obtain a variable loss rate using the equation
found on page E -9 of the manual, which is Ft = C(D -T) - 1.51 + Fn,. Variable loss
rates are not required for the Synthetic Unit Hydrograph Analysis (Shortcut
Method). Additionally, developed condition low loss rate calculations on 24 hour
duration storms have-been modified pursuant to recent Riverside County Flood
Control guidance.
15. Project Entrance and Emergency Route High Water Maximum Height
During any storm event, a minimum 10 foot wide paved surface at the entrance to
the site or localized sump area which would block emergency vehicular travel shall
never exceed a storm water depth of 1.0 feet at any time. During the major storm
100 yr storm (inches)
Zones
Thr
3hr
6hr '
24hr
Zone 1 - Southwest mountains
2.50
3.40
4.00
6.00
Zone 2 - Southwest mountains
2.30
3.00
3.70
5.00
Zone '3 - West mountains and areas south' of
Hwy 111 and west of Washington
2.20 "
2.80
3.40
4.50
Zone 4 - West of Jefferson and areas east of
Washington including the Cove
2.10
2.70
3.20
4.25
Zone 5 - East of Jefferson and west of a
staggered line trending south west of Calhoun
Street and Avenue 50
2.00
2.60_
3.10
4.00
Zone 6 - West of a staggered line trending south
west of Calhoun Street and Avenue 50
1.90
2.50
3.00
3.75
14. Hydrograph Loss Rates
According to the Riverside County Flood Control Hydrology Manual, the loss rates
generally range from 0.10 to 0.40 in /hr with most falling between 0.20 and 0.25
in /hr. Three and six hour duration storms may use a constant loss rate; however,
the 24 hour duration storm shall obtain a variable loss rate using the equation
found on page E -9 of the manual, which is Ft = C(D -T) - 1.51 + Fn,. Variable loss
rates are not required for the Synthetic Unit Hydrograph Analysis (Shortcut
Method). Additionally, developed condition low loss rate calculations on 24 hour
duration storms have-been modified pursuant to recent Riverside County Flood
Control guidance.
15. Project Entrance and Emergency Route High Water Maximum Height
During any storm event, a minimum 10 foot wide paved surface at the entrance to
the site or localized sump area which would block emergency vehicular travel shall
never exceed a storm water depth of 1.0 feet at any time. During the major storm
event, the proposed drainage will not block or unreasonably increase or concentrate
within the meaning of California Drainage Law, drainage runoff from or to any of
' the adjoining properties.
16. 10 Year Storm & Public Streets — Catch Basin Spacing
' For a design frequency storm of 10 years, the design maximum allowable arterial
spreads will equal 1 lane (10 - 12 feet) + bike lane (if present 4 — 8 feet). The
loss of only 1 lane of use is desired for 10 year storms. Catch basin spacing
generally is required between 1200 - 2000 .feet on City arterial roadways. The
engineer may provide calculations showing that the spacing may increase. The
' engineer must also demonstrate that the flow in the street will not topple over
curbs or R/W during changes in direction of the open channel conduit (typically the
'
street). Inlets will be required at locations on arterial streets prior to the flow
crossing at intersections and major driveways or entrances. Typically (verify with
the Conditions of Approval), inlets must be located to intercept at least 85% of the
total project projected storm flow. This also includes tributary areas found in the
public right of way.
' 17. 100 Year Storm and Public Streets
For a design frequency storm of 100 years, the design maximum allowable spreads
are to the respective City right of way.
18. Report Outline — The following shall be found within all hydrology reports:
• Signed and stamped by a California Registered Civil Engineer
' Table of Contents
•, Vicinity Map with Site Location
,' •' Project description with historical flow pattern exceeding a site
circumference of 1 mile, unless limited by clearly defined watershed
tboundaries
Analysis method used (Rational,or Synthetic Unit Hydrograph)
• Hydrology map showing all sub areas with coefficients.
• Rational Method showing tabling in a node -by -node sequence per Riverside
County Flood Control Manual or equal.
Soils map used to determine soil losses.
Catch Basin Sizing
I I
' • Retention Basin requirements with percolation as determined b field testing
9
and City policies. Please also provide retention basin volumetric calculations
assuming zero percolation for sensitivity analysis.
• Volume calculations w /Cross Sections of the Retention Basin.
19. Retention Basin Freeboard Requirements
A' minimum of 1 foot of freeboard between the retention basin major storm
' elevation (HGL,00 ) and the flow line of the nearest street (typically the inlet) is
required. The 1 foot minimum freeboard specification may be modified to a
reduced freeboard height which achieves 25% of the 100 year storm capacity in
large area, shallow retention basin configurations. Historical City maximum
t freeboard specifications are now eliminated.
20. Hydraulic Grade Line (HGL) Starting Points
Projects within the City of La Quinta that are required to contain their 100 year
storm flows shall show two (2) separate,HGLs for maximum flow rate (HGL,o) and
maximum volume (HGL,00)-
The first HGL (HGL,o) will reflect the values .from the 10 year frequency design
storm.1 ;. Values of Q,o and V,o will be determined from the Rational Method. Conduit
sizing shall be based on non pressure type flow (HGL shall not be located above the
crown of a pipe).
The second HGL (HGL,00) will reflect' values based on the maximum 100 year
frequency design storm. The HGL,00 shall show that the maximum 100 year storm
can be retained within the project and the use of the project's infrastructure shall
be maintained.
21. 10 Year Frequency Design Storm HGL Calculation
This HGL shall start at or above an elevation in the downstream retention basin
that is equal to the '/2 depth of the retention elevation caused by the 100 year
frequency design storm event. The piping system shall be designed based on open
channel flow as opposed to pressure flow. This HGL should indicate the hydraulic
conditions at the maximum storm water flow rate. Requirements:
• Pressure pipe flow not allowed
• Identify this HGL as the HGL,o on the hydraulic calculations and storm drain
plan profile
• Velocity not less than 2.5 fps
Pipe sized based on Rational Method
Head losses shall be 'based on HEC 22 Ch 7.
•
HGL freeboards: 6" or greater below CB flow line
' 22.
100 Year Frequency Design Storm HGL Calculation
This
HGL shall start at a location at the top of the retention basin water level
caused by the 100 year design storm determined using the Synthetic Unit
Hydeograph. This HGL should indicate the hydraulic conditions at the maximum
storm water volume with a full basin or channel. Requirements:
•
Velocity (no requirement)
•
Identify this HGL as the HGL,00 on the hydraulic calculations and storm drain
plan profile
•
Pressure pipe flow allowed.
' •
Pipe size based on Rational Method.
•
No part of the emergency route shall obtain a water depth greater than
1.5 feet.
•
HGL Freeboards and Elevations
•
Difference in elevation between CB flow line and HGL in retention basin
shall be between 0 and 12 inches.
•
1 ft min from top of manhole cover
•
Not to exceed 7ft above the top of pipe
•
. HGL must be located 1 ft below the adjacent Pad Elevation
1 23. Whitewater Channel HGL
.Assuming major storm coincidental occurrences are taken into consideration
already (see page 7 -8 of HEC -22 Storm Drains), the projects HGL100 shall be
located 2 feet below Whitewater Channel's estimated HGL500 (this is also equal to
1 foot below the existing Whitewater Concrete Channel Lining). Time of
concentration, for channel discharge will assume a full channel. Flap gate
installation may be applicable_ based on project elevations.
24. La Quinta Evacuation Channel HGL
1� The Evacuation Channel obtains an HGL,00 with an approximate elevation of 48.0
pursuant to information provided by CVWD to the City. Additional elevation
information for the Evacuation. Channel is currently under review at CVWD. The
' elevation is based on NGVD 1929. "Elevations showing on the plan should be based
on the same. Flap gate installation may be applicable based on project elevations.
1,
1 25. Retention Basin Landscape Requirements
' Retention basins shall be landscaped and properly irrigated. The retention basin
landscape plans must be approved by the City Engineer /Public Works Director. The
retention basin must be capable of draining the 100 year storm within 72 hours.
Project incapable of draining the 100 year storm within 72 hours will be reviewed
by the City for enhancement options to promote drainage conveyance. In basins
with depths exceeding 8ft, trees shall be planted in the 8 -foot wide terraces. The
' number of trees shall be calculated by multiplying the basin lot boundary length by
the number of 8 -foot wide terraces in the basin and then dividing by 100.
26. Typical Storm Drain Pipe Gradients & Velocity
' Primary street storm drains, designers should assume minimum grade = 0.3%.,
based on minimum flow velocity of 2.5 ft /sec. For local area drains, 4 " -6" pipe
minimum grade = 1 %, larger pipe diameters = 0.5% should be assumed.
27. Typical Street Flows
Street flows shall meet the design requirements of FHWA HEC -22. When gutters
obtain small slopes, or where sediment may accumulate, or when parking is
allowed on the side of the street, the designer should increase the n value by 0.02.
28. Storm Drain Easement Width Requirements
The City of La Quinta requirements for minimum widths (generally 20 feet,
excepting deep drainage systems) of storm drain easements is found in easement
requirement charts from the Riverside County Transportation Department. Ten (10)
foot easements using Reinforced Concrete Pipe (RCP) in side yards may be used at
the discretion of the City Engineer.
29. Surface Usage within the Retention Basin
The developer may 'use the retention basin surface for recreational activities
' (tennis, volley ball, park, etc) or other permitted usages approved by the
Community Development Director provided the retention basin's intended
engineering use is met and that typical ADA improvements are provided. All
improvements found within the retention basin shall be removed if they inhibit the
maintenance or function of the retention basin.
I
n
C'
s it
m m m m m m r m m m m
Q�OnF OUa6M NODE
PARC EL 2
PARCEL MAP 32 o 9
f 20' CVWD /
- -_ L - ; - _ - UTILITY E
C-�-
_ _ ' � �\ LOT 33 '
TRACT 28611
r 1a• , �� '�h 0
1
' I i
MAP
GRAPHIC
SCALE
= ioo ft-
(NP)
TRACT ACT P2677400 =9
LOT 91
(GOLF COURSE)
URSE)
LOT 35
TRACT 28611
619
m 00
1
AREA "B -1" \
A =1.14 AC \
'PE =54. \
I �P�1RCC L 9
'FARCE P 329M
M �
CB Al \
100 =2.71 CFS MAX \
NO E 11
i 10 =8.79 CFS MAX , �♦,
mom so
1 CB #2
O ,0100 =6.08 CFS MAX ♦♦
�tc\� PE =60.0
!�?\ ` TRACT 2077400
N� LOT 27 �o �
/ AREA "B -2' /
A =2.84 AC /
r �
' 1
1 NO BUILD ESMT 1
! LOT 36 as
� 1
TRACT 28740 ',9 � _ _ move w wo 00
' RCFC 8,WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -1"
3 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
5 AREA ACRES
1.1400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
8 L -MILES ([61-[71)
0.063
[91 LCA - INCHES
-
10 LCA - MILES ([71-[91)
0.009
[111 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
161.00
14 S - FEET /MILE ([13/[81)
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([8]'[101/[15])
0.0000111
17 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24-[17]-[16]-'0.38)
(PLATE E -3
0.0088816
19 LAG TIME - MINUTES (60'[18])
0.53
20 25% OF LAG TIME (0.25-[191)
0.13
[21140% OF LAG TIME (0.40"[19])
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAINFALL DATA
1 SOURCE
IRCFCWCD
2 FREQUENCY - YEARS
11 00YR 24HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
10
E [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
[M
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
[131
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= - F 7= 2.80
F 9= - F 11 =
3.40
F 13= - F 15= 4.50
F1 61 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1([161-
1
1
[1 7] ADJ.AVG.POINT RAIN 2.8
F [7],ETC)
3.4
4.5
RCFC SWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[3]
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.53
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[1 1] VARIABLE LOSS RATE (AVG) - IN /HR
O
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
13 CONSTANT LOSS RATE - IN /HR
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
rPERIOD
MAX
LOW
1
0.20
0.036
0.000
0.000
0.036
0.04
2
0.30
0.054
0.000
0.000
0.054
0.06
3
0.30
0.054
0.0001
0.000
0.054
0.06
4
0.40
0.072
0.000
0.000
0.072
0.08
5
0.30
0.054
0.000
0.000
0.054
0.06
6
0.30
0.054
0.000
0.000
0.054
0.06
7
0.30
0.054
0.000
0.000
0.054
0.06
8
0.40
0.072
0.000
0.000
0.072
0.08
9
0.40
0.072
0.000
0.000
0.072
0.08
10
0.40
0.072
0.000
0.000
0.072
0.08
11
0.50
0.090
0.000
0.000
0.090
0.10
12
0.50
0.090
0.000
0.000
0.090
0.10
13
0.50
0.090
0.000
0.000
0.090
0.10
14
0.50
0.090
0.000
0.000
0.090
0.10
15
0.50
0.090
0.000
0.000
0.090
0.10
16
0.60
0.108
0.000
0.000
0.108
0.12
17
0.60
0.108
0.000
0.000
0.108
0.12
18
0.70
0.126
0.000
0.000
0.126
0.14
19
0.70
0.126
0.0001
0.000
0.126
0.14
20
0.80
0.144
0.000
0.000
0.144
0.16
21
0.60
0.108
0.000
0.000
0.108
0.12
22
0.70
0.126
0.000
0.000
0.126
0.14
23
0.80
0.144
0.000
0.000
0.144
0.16
24
0.80
0.144
0.000
0.000
0.144
0.16
25
0.90
0.162
0.000
0.000
0.162
0.18
26
0.90
0.162
0.000
0.000
0.162
0.18
27
1.00
0.180
0.0001
0.000
0.180
0.21
28
1.00
0.180
0.000
0.000
0.180
0.21
29
1.00
0.180
0.000
0.000
0.180
0.21
30
1.10
0.198
0.000
0.000
0.198
0.23
31
1.2
0.216
0.000
0.000
0.216
0.25
32
1.30
0.234
0.000
0.000
0.234
0.27
33
1.50
0.270
0.000
0.000
0.270
0.31
34
1.50
0.270
0.000
0.000
0.270
0.31
35
1.601
0.288
0.000
0.000
0.288
0.33
36
1 1.701
0.306
0.000
0.000
0.306
0.35
I RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[41 ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.53
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
4.5
[1 1] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE - INCHES PER HO
0
[14] LOW LOSS RATE - PERCENT
I
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
6010 20
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
37
1.90
0.342
0.000
-
0.342
0.39
38
2.00
0.360
0.000
-
0.360
0.41
39
2.10
0.378
0.0001-
0.378
0.43
40
2.20
0.396
0.0001-
0.396
0.45
41
1.50
0.270
0.000
0.000
0.270
0.31
42
1.50
0.270
0.000
0.000
0.270
0.31
43
2.00
0.360
0.000-
0.360
0.41
44
2.00
0.360
0.000-
0.360
0.41
45
1.90
0.342
0.000
0.000
0.342
0.39
46
1.90
0.342
0.0001
0.000
0.342
0.39
47
1.70
0.306
0.000
0.000
0.3061
0.35
48
1.80
0.324
0.000
0.000
0.324
0.37
49
2.50
0.450
0.000-
0.450
0.51
50
2.60
0.468
0.000-
0.468
0.53
51
2.80
0.504
0.000-
0.504
0.57
52
2.90
0.522
0.000-
0.522
0.60
53
3.40
0.612
0.000-
0.6121
0.70
54
3.40
0.612
0.000
-
0.612
0.70
55
2.30
0.414
0.000
-
0.414
0.47
56
2.30
0.414
0.000.-
0.414
0.47
57
2.70
0.486
0.0001-
0.486
0.55
58
2.60
0.468
0.000-
0.468
0.53
59
2.60
0.468
0.0067
0.468
0.53
60
2.50
0.450
0.000-
0.450
0.51
61
2.40
0.432
0.000-
0.432
0.49
62
2.30
0.414
0.000-
0.414
0.47
63
1.90
0.342
0.000
0.000
0.3421
0.39
64
1.90
0.342
0.000
0.000
0.342
0.39
65
0.40
0.072
0.000
0.000
0.072
0.08
66
0.40
0.072
0.000
0.000
0.072
0.08
67
0.30
0.054
0.000
0.000
0.054
0.06
68
0.30
0.054
0.000
0.000
0.054
0.06
69
0.50
0.090
0.000
0.000
0.090
0.10
70
0.50
0.090
0.000
0.000
0.090
0.10
71
0.50
0.090
0.000
0.000
0.090
0.10
72
0.40
0.072
0.000
0.000
0.072
0.08
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.53
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
4.5
111! 11 VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE - INCHES PER HO
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4' 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21 ]
STORM
RAIN
IN /HR
60[101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
ff
LOW
73
0.40
0.072
0.000
0.000
0.072
0.08
74
0.40
0.072
0.000
0.000
0.072
0.08
75
0.30
0.054
0.000
0.000
0.054
0.06
76
0.20
0.036
0.000
0.000
0.036
0.04
77
0.30
0.054
0.000
0.000
0.054
0.06
78
0.40
0.072
0.000
0.000
0.072
0.08
79
0.30
0.054
0.000
0.000
0.054
0.06
80
0.20
0.036
0.000
0.000
0.036
0.04
81
0.30
0.054
0.000
0.000
0.054
0.06
82
0.30
0.054
0.000
0.000
0.054
0.06
83
0.30
0.054
0.0001
0.000
0.054
0.06
84
0.20
0.036
0.0001
0.000
0.036
0.04
85
0.30
0.054
0.0001
0.000
0.054
0.06
86
0.20
0.036
0.000
0.000
0.036
0.04
87
0.30
0.054
0.000
0.000
0.054
0.06
88
0.20
0.036
0.000
0.000
0.036
0.04
89
0.30
0.054
0.000
0.000
0.054
0.06
90
0.20
0.036
0.000
0.000
0.036
0.04
91
0.20
0:036
0.000
0.000
0.036
0.04
92
0.20
0.036
0.000
0.000
0.036
0.04
93
0.20
0.036
0.000
0.000
0.036
0.04
94
0.20
0.036
0.000
0.000
0.036
0.04
95
0.20
0.036
0.000
0.000
0.036
0.04
96
0.20
0.036
0.000
0.000
0.036
0.04
F =100%
F=
18.000
8404CF
A/G STORAGE
OCF
U/G STORAGE
18.00 IN /HR *0.25= 4.50 "
4.50 " * 0.083 * 1.1400 ACRES=
0.4258 AC FT= 18547 CF
OCF
IPERC LOSS IN 24 HRS
8404CF
PROVIDED
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32981
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
[51 AREA ACRES
1.1400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
[81L-MILES ([61-[71)
0.063
9 LCA - INCHES
-
10 LCA - MILES ( [71'[91
0.009
[111 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 1l]-[l 2
161.00
14 S - FEET /MILE ([13/[8])
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([81-[101/[15])
0.00001122
[171 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24'[171-[16]-'0.38)
(PLATE E -3
0.009
19 LAG TIME - MINUTES (60-[18])
0.54
[20125% OF LAG TIME (0.25'[191)
0.13
[21140% OF LAG TIME 0.40-[19]
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAI NFALL DATA
1 SOURCE
IRCFCWCD
2 FREQUENCY - YEARS
11 00YR 3HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
[5�
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
Im
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
031
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= - F 7= 2.80
F 9= -
F 11 =
3.40
F 13= - F 15= 4.50
rl 61 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1
1
[17] ADJ.AVG.POINT RAIN 2.8
([16]* F [71,ETC)
3.4
4.5
I RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32981
BY: AMG
DATE: 5127/08
JOB* 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
(3) DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
10
[6] LAG TIME - MINUTES
0.54
[7] UNIT TIME - PERCENT OF LAG (100 *[5] /[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 3HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
2.8
1[111 VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
13 CONSTANT LOSS RATE- INCHES PER HOUR
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21 ]
STORM
RAIN
IN /HR
60110][201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
100[5]
MAX
LOW
1
2.60
0.437
0.00
0.437
0.50
2
2.60
0.437
0.00
0.437
0.50
3
3.30
0.554
0.00
0.554
0.63
4
3.30
0.554
0.00
0.554
0.63
5
3.30
0.554
0.00
0.554
0.63
6
3.40
0.571
0.00
0.571
0.65
7
4.40
0.739
0.00
0.739
0.84
8
4.20
0.706
0.00
0.706
0.80
9
5.30
0.890
0.00
0.890
1.02
10
5.10
0.857
0.00
0.857
0.98
11
6.40
1.075
0.00
1.075
1.23
12
5.90
0.991
0.00
0.991
1.13
13
7.30
1.226
0.00
1.226
1.40
14
8.50
1.428
0.00
1.428
1.63
15
14.10
2.369
0.00
2.369
2.70
16
14.10
2.369
0.00
2.369
2.70
17
3.80
0.638
0.00
0.638
0.73
18
2.40
0.403
0.00
0.403
0.46
7-= 100%
F= 16.80
8404 CF
A/G STORAGE
0 CF
U/G STORAGE 16.80 IN /HR *0.17= 2.80 "
PERC LOSS IN 3 HRS 2.80 " * 0.083 * 1.1400 ACRES=
PROVIDED 0.2649 AC FT= 11540.61 CF
0 CF
8404 CF
PROJECT: PM 32981
BY: AMG 100 YR / 3 HR
DATE: 5/27/08
JOB M 06002
RAINFALL INTENSITY (IN /HR)
2.500
2.000
1.500
1.000
0.500
0.000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Q100 / 3HR
3.00
2.50
2.00
1.50
1.00
0.50
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
[31 AREA - SQ INCHES
-
4 AREA ADJUSTMENT FACTOR
-
5 AREA -ACRES
1.1400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
[81L-MILES ([61-[71)
0.063
f9l LCA - INCHES
-
10 LCA - MILES ( [71'[91
0.009
[111 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
161.00
14 S - FEET /MILE ([13/[81)
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([81-[10]/[15])
0.00001122
17 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24-[17]-[16]'-0.38)
(PLATE E -3
0.00891937
19 LAG TIME - MINUTES (60'[181)
0.54
20 25% OF LAG TIME (0.25-[19])
0.13
[21140% OF LAG TIME (0.40-[19])
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAI NFALL DATA
[1 ]SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
jl00YR6HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
L5j
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
U
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13] [14]
AREA L3j
SQ F [13]
INCHES
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= 15.45 F 7= 2.80
F 9= 19.7 F
11 =
3.40
F 13= 19.7 F 15= 4.50
Tl 61 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1([161-
1
1
[17] ADJ.AVG. POI NT RAIN 2.8
E [7], ETC)
3.4
4.5
RCFC 8,WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
(1) CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[3)
N/A
[5) UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.54
[7] UNIT TIME - PERCENT OF LAG (100 *[5] /[6))
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 6HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
3.4
11) VARIABLE LOSS RATE (AVG) - INCHES /HOUR
O
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13) CONSTANT LOSS RATE- INCHES PER HOUR
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
141 *1`181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60f101f201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
MAX
LOW
1
1.70
0.231
0.00
0.00
0.23
0.3
2
1.90
0.258
0.00
0.00
0.26
0.3
3
2.10
0.286
0.00
0.00
0.29
0.3
4
2.20
0.299
0.00
0.00
0.30
0.3
5
2.40
0.326
0.00
0.00
0.33
0.4
6
2.40
0.326
0.00
0.001
0.33
0.4
7
2.40
0.326
0.00
0.00
0.33
0.4
8
2.50
0.340
0.00
0.00
0.34
0.4
9
2.60
0.354
0.00
0.00
0.35
0.4
10
2.70
0.367
0.00
0.00
0.37
0.4
11
2.80
0.381
0.00
0.00
0.38
0.4
12
3.00
0.408
0.00
0.001
0.41
0.5
13
3.20
0.435
0.00
0.001
0.44
0.5
14
3.60
0.490
0.00
0.001
0.49
0.6
15
4.30
0.585
0.00
0.00
0.58
0.7
16
4.70
0.639
0.00
0.00
0.64
0.7
17
5.40
0.734
0.00
0.00
0.73
0.8
18
6.20
0.843
0.00
0.00
0.84
1.0
19
6.90
1.020
0.00
0.00
1.02
1.2
20
7.50
1.442
0.00
0.001
1.44
1.6
21
10.60
1.972
0.00
0.00
1.97
2.2
22
14.50
0.462
0.00
0.00
0.46
0.5
23
3.40
0.136
0.00
0.00
0.14
0.2
24
1.00
0.136
0.00
0.00
0.14
0.2
8404 CF
A/G STORAGE
0 CF
U/G STORAGE
0 CF
PERC LOSS IN 6 HRS
8404 CF
PROVIDED
1=100%
7= 7.63
7.63 IN /HR *0.25= 1.9074 "
1.9074 " * 0.083 * 1.1400 ACRES=
0.1805 AC FT= 7861.63 CF
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
2.50
100 YR / 6 HR
RAINFALL INTENSITY (IN /HR)
23 24
2 23 24
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE:' 5/27/08 '
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 3HR
11540.61 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
2.6
300.06
0.00
0.00
2
2.6
300.06
0.00
0.00
3
3.3
380.84
0.00
0.00
4
3.3
380.84
0.00
0.00
5
3.3
380.84
0.00
0.00
6
3.4
392.38
0.00
0.00
7
4.4
507.79
0.00
0.00
8
4.2
484.71
0.00
0.00
9
5.3
611.65
0.00
0.00
10
5.1
588.57
0.00
0.00
11
6.4
738.60
0.00
0.00
12
5.9
680.90
0.00
0.00
13
7.3
842.46
0.00
0.00
14
8.5
980.95
0.00
0.00
15
14.1
1627.23
793.87
1.32
16
14.1
1627.23
1627.23
2.71
17
3.8
438.54
438.54
0.73
18
2.4
276.97
276.97
0.46
E=
11540.61
SHT 1 OF 5
r
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 6HR 7861.63 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
1.7
133.65
0.00
0.00
2
1.9
149.37
0.00
0.00
3
2.1
165.09
0.00
0.00
4
2.2
172.96
0.00
0.00
5
2.4
188.68
0.00
0.00
6
2.4
188.68
0.00
0.00
7
2.4
188.68
0.00
0.00
8
2.5
196.54
0.00
0.00
9
2.6
204.40
0.00
0.00
10
2.7
212.26
0.00
0.00
11
2.8
220.13
0.00
0.00
12
3.0
235.85
0.00
0.00
13
3.2
251.57
0.00
0.00
14
3.6
283.02
0.00
0.00
15
4.3
338.05
0.00
0.00
16
4.7
369.50
0.00
0.00
17
5.4
424.53
0.00
0.00
18
6.2
487.42
0.00
0.00
19
6.9
542.45
0.00
0.00
20
7.5
589.62
0.00
0.00
21
10.6
833.33
0.00
0.00
22
14.5
1139.94
0.00
0.00
23
3.4
267.30
0.00
0.00
24
1.0
78.62
0.00
0.00
F=
7861.63
SHT 2 OF 5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
0.20
37.09
0.00
0.00
2
0.30
55.64
0.00
0.00
3
0.30
55.64
0.00
0.00
4
0.40
74.19
0.00
0.00
5
0.30
55.64
0.00
0.00
6
0.30
55.64
0.00
0.00
7
0.30
55.64
0.00
0.00
8
0.40
74.19
0.00
0.00
9
0.40
74.19
0.00
0.00
10
0.40
74.19
0.00
0.00
11
0.50
92.74
0.00
0.00
12
0.50
92.74
0.00
0.00
13
0.50
92.74
0.00
0.00
14
0.50
92.74
0.00
0.00
15
0.50
92.74
0.00
0.00
16
0.60
111.28
0.00
0.00
17
0.60
111.28
0.00
0.00
18
0.70
129.83
0.00
0.00
19
0.70
129.83
0.00
0.00
20
0.80
148.38
0.00
0.00
21
0.60
111.28
0.00
0.00
22
0.70
129.83
0.00
0.00
23
0.80
148.38
0.00
0.00
24
0.80
148.38
0.00
0.00
25
0.90
166.92
0.00
0.00
26
0.90
166.92
0.00
0.00
27
1.00
185.47
0.00
0.00
28
1.00
185.47
0.00
0.00
29
1.00
185.47
0.00
0.00
30
1.10
204.02
0.00
0.00
31
1.20
222.56
0.00
0.00
32
1.30
241.11
0.00
0.00
33
1.50
278.21
0.00
0.00
34
1.50
278.21
0.00
0.00
35
1.60
296.75
0.00
0.00
36
1.70
315.30
0.00
0.00
37
1.90
352.39
0.00
0.00
38
2.00
370.94
0.00
0.00
39
2.10
389.49
0.00
0.00
40
2.20
408.03
0.00
0.00
41
1.50
278.21
0.00
0.00
42
1.50
278.21
0.00
0.00
43
2.00
370.94
0.00
0.00 '
44
2.00
370.94
0.00
0.00
45
1.90
352.39
0.00
0.00
46
1.90
352.39
90.53
0.10
t
SHT3OF5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
47
1.70
315.30
315.30
0.35
48
1.80
333.85
333.85
0.37
49
2.50
463.68
463.68
0.52
50
2.60
482.22
482.22
0.54
51
2.80
519.32
519.32
0.58
52
2.90
537.86
537.86
0.60
53
3.40
630.60
630.60
0.70
54
3.40
630.60
630.60
0.70
55
2.30
426.58
426.58
0.47
56
2.30
426.58
426.58
0.47
57
2.70
500.77
500.77
0.56
58
2.60
482.22
482.22
0.54
59
2.60
482.22
482.22
0.54
60
2.50
463.68
463.68
0.52
61
2.40
445.13
445.13
0.49
62
2.30
426.58
426.58
0.47
63
1.90
352.39
352.39
0.39
64
1.90
352.39
352.39
0.39
65
0.40
74.19
74.19
0.08
66
0.40
74.19
74.19
0.08
67
0.30
55.64
55.64
0.06
68
0.30
55.64
55.64
0.06
69
0.50
92.74
92.74
0.10
70
0.50
92.74
92.74
0.10
71
0.50
92.74
92.74
0.10
72
0.40
74.19
74.19
0.08
73
0.40
74.19
74.19
0.08
74
0.40
74.19
74.19
0.08
75
0:30
55.64
55.64
0.06
76
0.20
37.09
37.09
0.04
77
0.30
55.64
55.64
0.06
78
0.40
74.19
74.19
0.08
79
0.30
55.64
55.64
0.06
80
0.20
37.09
37.09
0.04
81
0.30
55.64
55.64-
0.06
82
0.30
55.64
55.64
0.06
83
0.30
55.64
55.64
0.06
84
0.20
37.09
37.09
0.04
85
0.30
55.64
55.64
0.06
86
0.20
37.09
37.09
0.04
87
55.64
55.64
0.06
88
37.09
37.09
0.04
89
55.64
55.64
0.06
90
AO.20
37.09
37.09
0.04
91
37.09
37.09
0.04
92
37.09
37.09
0.04
SHT 4 OF 5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE = 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
93
0.20
37.09
37.09
0.04
94
0.20
37.09
37.09
0.04
95
0.20
37.09
37.09
0.04
96
0.20
37.09
37.09
0.04
F=
18547.00
J
i
t
SHT 5 OF 5
r
RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: LOT 27 TR28470 -1
BY: AMG
DATE: 5/27/08
JOB* 06002
1 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
3 AREA - SQ INCHES
-
4 AREA ADJUSTMENT FACTOR
-
5 AREA ACRES
2.8400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
[81L-MILES ([61-[71)
0.122
f9l LCA - INCHES
-
10 LCA - MILES ( [71*[91
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 1l]-[l 2
311.00
14 S - FEET /MILE ([13/[81)
2549.18
15 S * *0.5
50.49
16 L *LCA/S * *.5 8 * 10 / 15
0.0000375
[171 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24*[ 17]-[16]'-0.38)
(PLATE E -3
0.0141033
[191 LAG TIME - MINUTES (60-[18])
0.85
[20125% OF LAG TIME 0.25* 19
0.21
[21140% OF LAG TIME 0.40* 19
0.34
[22] UNIT TIME - MINUTES ( 25 -[21])
24.66
RAINFALL DATA
[1 ]SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
1100YR 24HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
fQ
F [5]
[7]
AVG.
POINT
RAIN IN,
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10].
U
Z [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
1`131
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= - F 7= 2.80
7 9= -
F 11 =
3.40
F 13= - F 15= 4.50
[161 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1
1
[17] ADJ.AVG.POINT RAIN 2.8
([161* F [7], ETC)
3.4
4.5
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28470 -1
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA -ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME -PERCENT OF LAG (100 '[5] /[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[l 11 VARIABLE LOSS RATE (AVG) - IN /HR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13 CONSTANT LOSS RATE - IN /HR
0
[14] LOW LOSS RATE - PERCENT
0
[]NIT HYI)ROr.RAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4' 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
1
0.20
0.036
0.000
0.000
0.036
0.10
2
0.30
0.054
0.000
0.000
0.054
0.15
3
0.30
0.054
0.000
0.000
0.054
0.15
4
0.40
0.072
0.000
0.000
0.072
0.20
5
0.30
0.054
0.000
0.000
0.054
0.15
6
0.30
0.054
0.000
0.000
0.054
0.15
7
0.30
0.054
0.000
0.000
0.054
0.15
8
0.40
0.072
0.000
0.000
0.072
0.20
9
0.40
0.072
0.000
0.000
0.072
0.20
10
0.40
0.072
0.000
0.000
0.072
0.20
11
0.50
0.090
0.0001
0.000
0.090
0.26
12
0.50
0.090
0.000
0.000
0.090
0.26
13
0.50
To-go
0.000
0.000
0.090
0.26
14
0.50
0.090
0.000
0.000
0.090
0.26
15
0.50
0.090
0.000
0.000
0.090
0.26
16
0.60
0.108
0.000
0.000
0.108
0.31
17
0.60
0.108
0.0001
0.000
0.108
0.31
18
0.70
0.126
0.0001
0.000
0.126
0.36
19
0.70
0.126
0.000
0.000
0.126
0.36
20
0.80
0.144
0.000
0.000
0.144
0.41
21
0.60
0.108
0.000
0.000
0.108
0.31
22
0.70
0.126
0.000
0.000
0.126
0.36
23
0.80
0.144
0.000
0.000
0.144
0.41
24
0.80
0.144
0.000
0.000
0.144
0.41
25
0.90
0.162
0.000
0.000
0.162
0.46
26
0.90
0.162
0.000
0.000
0.162
0.46
27
1.00
0.180
0.000
0.000
0.180
0.51
28
1.00
0.180
0.000
0.000
0.180
0.51
29
1.00
0.180
0.000
0.000
0.180
0.51
30
1.10
0.198
0.000
0.000
0.198
0.56
31
1.2
0.216
0.000
0.000
0.216
0.61
32
1.30
0.234
0.000
0.000
0.234
0.66
33
1.50
0.270
0.000
0.000
0.270
0.77
34
1.50
0.270
0.000
0.000
0.270
0.77
35
1.60
0.288
0.000
0.000
0.288
0.82
36
1.70
0.306
0.000
0.000
0.306
0.87
1 RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: LOT 27 TR28470 -1
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET BY: AMG
DATE: 5/27/08
JOB* 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA -ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6))
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[11] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE - INCHES PER HOQ
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
- [17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4' 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
601101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
37
1.90
0.342
0.000
0.000
0.342
0.97
38
2.00
0.360
0.000
0.000
0.360
1.02
39
2.10
0.378
0.0001
0.000
0.378
1.07
40
2.20
0.396
0.0001
0.000
0.396
1.12
41
1.50
0.270
0.000
0.000
0.270
0.77
42
1.50
0.270
0.000
0.000
0.270
0.77
43
2.00
0.360
0.000
0.000
0.360
1.02
44
2.00
0.360
0.000
0.000
0.360
1.02
45
1.90
0.342
0.000
0.000
0.342
0.97
46
1.90
0.342
0.000
0.000
0.342
0.97
47
1.70
0.306
0.000
0.000
0.306
0.87
48
1.80
0.324
0.000
0.000
0.324
0.92
49
2.50
0.450
0.000
0.000
0.450
1.28
50
2.60
0.468
0.0001
0.000
0.468
1.33
51
2.80
0.504
0.000
0.000
0.5041
1.43
52
2.90
0.522
0.000
0.000
0.522
1.48
53
3.40
0.612
0.000
0.000
0.612
1.74
54
3.40
0.612
0.000
0.000
0.612
1.74
55
2.30
0.414
0.000
0.000
0.414
1.18
56
2.30
0.414
0.000
0.000
0.414
1.18
57
2.70
0.486
0.000
0.000
0.486
1.38
58
2.60
0.468
0.000
0.000
0.468
1.33
59
2.60
0.468
0.000
0.000
0.468
1.33
60
2.50
0.450
0.000
0.000
0.450
728
61
2.40
0.432
0.000
0.000
0.432
1.23
62
2.30
0.414
0.000
0.000
0.414
1.18
63
1.90
0.342
0.000
0.000
0.342
0.97
64
1.90
0.342
0.000
0:000
0.342
0.97
65
0.40
0.072
0.000
0.000
0.072
0.20
66
0.40
0.072
0.0001
0.000
0.072
0.20
67
0.30
0.054
0.0001
0.000
0.054
0.15
68
0.30
0.054
0.0001
0.000
0.054
0.15
69
0.50
0.090
0.000
0.000
0.090
0.26
70
0.50
0.090
0.000
0.000
0.090
0.26
71
0.50
0.090
0.000
0.000
0.090
0.26
72
0.40
0.072
0.000
0.000
0.072
0.20
I' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28470 -1
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[91 STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
4.5
(1 1] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE - INCHES PER HOQ
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[41 *1181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
73
0.40
0.072
0.000
0.000
0.072
0.20
74
0.40
0.072
0.000
0.000
0.072
0.20
75
0.30
0.054
0.000
0.000
0.054
0.15
76
0.20
0.036
0.000
0.000
0.036
0.10
77
0.30
0.054
0.000
0.000
0.054
0.15
78
0.40
0.072
0.000
0.000
0.072
0.20
79
0.30
0.054
0.000
0.000
0.054
0.15
80
0.20
0.036
0.000
0.000
0.036
0.10
81
0.30
0.054
0.000
0.000
0.054
0.15
82
0.30
0.054
0.000
0.000
0.054
0.15
83
0.30
0.054
0.000
0.000
0.054
0.15
84
0.20
0.036
0.000
0.000
0.036
0.10
85
0.30
0.054
0.000
0.000
0.054
0.15
86
0.20
0.036
0.000
0.000
0.036
0.10
87
0.30
0.054
0.000
0.000
0.054
0.15
88
0.20
0.036
0.000
0.000
0.036
0.10
89
0.30
0.054
0.0001
0.000
0.054
0.15
90
0.20
0.036
0.000
0.000
0.036
0.10
91
0.20
0.036
0.000
0.000
0.036
0.10
92
0.20
0.036
0.000
0.000
0.036
0.10
93
0.20
0.036
0.000
0.000
0.036
0.10
94
0.20
0.036
0.000
0.000
0.036
0.10
95
0.20
0.036
0.000
0.000
0.036
0.10
96
0.20
0.036
0.000
0.000
0.036
0.10
F =100%
7-=
18.000
10484C
A/G STORAGE
OCF
U/G STORAGE
18.00 IN /HR *0.25= 4.50 "
4.50 " * 0.083 2.8400 ACRES=
1.0607 AC FT= 46206 CF
OCF
PERC LOSS IN 24 HRS
10484CF
PROVIDED
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: LOT 27 TR287401
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
5 AREA ACRES
2.8400
6 L- INCHES
[71L-ADJUSTMENT FACTOR
-
8 L -MILES ([61'[71)
0.122
9 LCA - INCHES
-
10 LCA - MILES ( [71-[91
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - l 21
311.00
14 S - FEET /MILE [13/[81
2549.18
15 S * *0.5
50.49
16 L *LCA/S * *.5 ([8]"[10]/[15])
0.00003866
[171 AVERAGE MANNING "N"
0.015
[181 LAG TIME - HOURS (24-[ 17]-[16]'-0.38)
(PLATE E -3
0.014
[191 LAG TIME - MINUTES 60-[18]
0.86
[20125% OF LAG TIME (0.25-[19])
0.21
[21140% OF LAG TIME 0.40* 19
0.34
[22] UNIT TIME - MINUTES ( 25 -[21])
24.66
RAINFALL DATA
[1 ]SOURCE
IRCFCWCD
2 FREQUENCY -YEARS
1100YR 3HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
L5j
E [5]
[7]
AVG.
POINT
RAIN IN,
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
j9]
7- [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
L131
Z [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
5= - F 7= 2.80
7 9= -
E [ill=
3.40
13= - F 15= 4.50
Tl 61 AREAL ADJ FACTOR 0.9
SEE PLATE E -5.8
1([16]-
0.9
0.9
[17] ADJ.AVG.POINT RAIN 2.52
F [71, ETC)
3.06
4.05
I RCFC SWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28.
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.840014]
ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
10
[6] LAG TIME - MINUTES
0.86
[7] UNIT TIME - PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[91 STORM FREQUENCY & DURATION
1 OOYR 3HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
2.52
IfIll VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[121 MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
O
13 CONSTANT LOSS RATE- INCHES PER HOUR
0
[14] LOW LOSS RATE - PERCENT
1 0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21 ]
STORM
RAIN
IN /HR
6011011201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
100[5]
MAX
LOW
1
2.60
0.393
0.00
0.393
1.12
2
2.60
0.393
0.00
0.393
1.12
3
3.30
0.499
0.00
0.499
1.42
4
3.30
0.499
0.00
0.499
1.42
5
3.30
0.499
0.00
0.499
1.42
6
3.40
0.514
0.00
0.514
1.46
7
4.40
0.665
0.00
0.665
1.89
8
4.20
0.635
0.00
0.635
1.80
9
5.30
0.801
0.00
0.801
2.28
10
5.10
0.771
0.00
0.771
2.19
11
6.40
0.968
0.00
0.968
2.75
12
5.90
0.892
0.00
0.892
2.53
13
7.30
1.104
0.00
1.104
3.13
14
8.50
1.285
0.00
1.285
3.65
15
14.10
2.132
0.00
2.132
6.05
16
14.10
2.132
0.00
2.132
6.05
17
3.80
0.575
0.00
0.575
1.63
18
2.40
0.363
0.00
0.363
1.03
F= 100%
F= 15.12
10484 CF
A/G STORAGE
0 CF
U/G STORAGE 15.12 IN /HR *0.17= 2.52 "
PERC LOSS IN 3 HRS 2.52 " * 0.083 * 2.8400 ACRES=
PROVIDED 0.5940 AC FT= 25875.27 CF
0 CF
10484 CF
PROJECT: LOT 27 TR287401
BY: AMG 100 "R / 3 HR
D,.TE: 5/27/08
JOB M OE002
2.500
RAINFALL INTENSITY (IN /HR)
2.000
1.500
1.000
0.500 Tit
0.000
2 3 4 s 6 7 8 9 10 11 12 13 14 18 16 17 18
Q100 / 3HR
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
1 2. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17' 18
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: LOT 27 TR28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
5 AREA -ACRES
2.8400
6 L- INCHES
-
7 L- ADJUSTMENT FACTOR
-
[811--MILES ([61-[71)
0.122
f9l LCA - INCHES
-
10 LCA - MILES ([71'[91
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
311.00
14 S - FEET /MILE ([13/[81)
2549.18
15 S * *0.5
50.49
16 L *LCA/S * *.5 ([8]-[10]/[15])
0.00003866
[171 AVERAGE MANNING "N"
0.015
[181 LAG TIME - HOURS (24-[ 17]-[16]--0.38)
(PLATE E -3
0.01427451
[191 LAG TIME - MINUTES (60-[18])
0.86
20 25% OF LAG TIME (0.25'[19])
0.21
[21140% OF LAG TIME (0.40'[19])
0.34
[22] UNIT TIME - MINUTES (25 -[21])
24.66
RAINFALL DATA
[1 ]SOURCE
IRCFCWCD
2 FREQUENCY - YEARS
11 00YR 6HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
f5�
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
f99
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13] [14]
AREA 1`131
SQ F [13]
INCHES
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= 15.45 F 7= 2.80
F 9= 19.7 E 11 =
3.40
F 13= 19.7 E 15= 4.50
16 AREAL ADJ FACTOR 0.9
SEE PLATE E -5.8
1([16]'
0.9
0.9
[17] ADJ.AVG.POINT RAIN 2.52
F [7],ETC)
3.06
4.05
I RCFC 8,WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06002
]
2M
N
R
U
5]
"B -2"
E- CFS- HRS /IN (645'[31
N/A
MAX
0.86
).208
DESERT
FORM RAIN - INCHES
3.06
(FOR VAR. LOSS) -IN /HR
).233
RCENT
0
]
2M
N
R
U
5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[2l]-[22]
[24]
FLOW
CFS
MAX
LOW
).208
0.00
0.00
0.21
0.6
).233
0.00
0.00
0.23
0.7
).257
0.00
0.00
0.26
0.7
).269
0.00
0.00
0.27
0.8
).294
0.00
0.00
0.29
0.8
).294
0.00
0.00
0.29
0.8
).294
0.00
0.00
0.29
0.8
).306
0.00
0.00
0.31
0.9
).318
0.00
0.00
0.32
0.9
).330
0.00
0.00
0.33
0.9
).343
0.00
0.00
0.34
1.0
).367
0.00
0.00
0.37
1.0
).392
0.00
0.00
0.39
1.1
).441
0.00
0.00
0.44
1.3
).526
0.00
0.00
0.53
1.5
).575
0.00
0.00
0.58
1.6
).661
0.00
0.00
0.66
1.9
).759
0.00
0.00
0.76
2.2
).918
0.00
0.00
0.92
2.6
1.297
0.00
0.00
1.30
3.7
1.775
0.00
0.00
1.77
5.0
).416
0.00
0.00
0.42
1.2
).122
0.00
0.00
0.12
0.3
).122
0.00
0.00
0.12
0.3
7= 6.87
7167 "
8400 ACRES=
?6.60 CF
PROJECT:. LOT 27 TR28740 -1
BY: AMG
DATE: 5/27/08 100 YR / 6 HR
JOE M 06002
RAINFALL INTENSITY (IN /HR)
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
0100 / 6HR
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE = 10484.00 CF
100 YR 3HR
25875.27 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
2.6
672.76
0.00
0.00
2
2.6
672.76
0.00
0.00
3
3.3
853.88
0.00
0.00
4
3.3
853.88
0.00
0.00
5
3.3
853.88
0.00 ,
0.00
6
3.4
879.76
0.00
0.00
7
4.4
1138.51
0.00
0.00
8
4.2
1086.76
0.00
0.00
9
5.3
1371.39
0.00
0.00
10
5.1
1319.64
0.00
0.00
11
6.4
1656.02
780.78
1.30
12
5.9
1526.64
1526.64
2.54
13
7.3
1888.89
1888.89
3.15
14
8.5
2199.40
2199.40
3.67
15
14.1
3648.41
3648.41
6.08
16
14.1
3648.41
3648.41
6.08
17
3.8
983.26
983.26
1.64
18
2.4
621.01
621.01
1.04
F=
25875.271
1
SHT 1 OF 5
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 6HR 17626.60 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
1.7
299.65
0.00
0.00
2
1.9
334.91
0.00
0.00
3
2.1
370.16
0.00
0.00
4
2.2
387.79
0.00
0.00
5
2.4
423.04
0.00
0.00
6
2.4
423.04
0.00
0.00
7
2.4
423.04
0.00
0.00
8
2.5
440.67
. 0.00
0.00
9
2.6
458.29
0.00
0.00
'10
2.7
475.92
0.00
0.00
11
2.8
493.54
0.00
0.00
12
3.0
528.80
0.00
0.00
13
3.2
564.05
0.00
0.00
14
3.6
634.56
0.00
0.00
15
4.3
757.94
0.00
0.00
16
4.7
828.45
0.00
0.00
17
5.4
951.84
0.00
0.00
18
6.2
1092.85
0.00
0.00
1.9
6.9
1216.24
620.76
0.69
20
7.5
1322.00
1244.23
1.38
21
10.6
1868.42
1868.42
2.08
22
14.5
2555.86
•2555.86
2.84
23
3.4
599.30
599.30
0.67
24
1.0
176.27
176.27
0.20
1=1
17626.60
1
SHT 2 OF 5
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
0.20
92.41
0.00
0.00
2
0.30
138.62
0.00
0.00
3
0.30
138.62
0.00
0.00
4
0.40
184.82
0.00
0.00
5
0.30
138.62
0.00
0.00
6
0.30
138.62
0.00
0.00
7
0.30
138.62
0.00
0.00 '
8
0.40
184.82
0.00
0.00
9
0.40
184.82
0.00
0.00
10
0.40
184.82
0.00
0.00
11
0.50
231.03
0.00
0.00
12
0.50
231.03
0.00
0.00
13
0.50
231.03
0.00
0.00
14
0.50
231.03
0.00
0.00
15
0.50
231.03
0.00
0.00
16
0.60
277.24
0.00
0.00
17
0.60
277.24
0.00
0.00
18
0.70
323.44
0.00
0.00
19
0.70
323.44
0.00
0.00
20
0.80
369.65
0.00
0.00
21
0.60
277.24
0.00
0.00
22
0.70
323.44
0.00
0.00
23
0.80
369.65
0.00
0.00
24
0.80
369.65
0.00
0.00
25
0.90
415.85
0.00
0.00
26
0.90
415.85
0.00
0.00
27
1.00
462.06
0.00
0.00
28
1.00
462.06
0.00
0.00
29
1.00
462.06
0.00
0.00
30
1.10
508.27'
0.00
0.00
31
1.2
554.47
0.00
0.00
32
1.30
600.68
0.00
0.00
33
1.50
693.09
0.00
0.00
34
1.50
693.09
318.62
0.35
35
1.60
739.30
739.30
0.82
36
1.70
785.50
785.50
0.87
37
1.90
877.91
877.91
0.98
38
2.00
924.12
924.12
1.03
39
2.10
970.33
970.33
1.08
40
2.20
1016.53
1016.53
1.13
41
1.50
693.09
693.09
0.77
42
1.50
693.09
693.09
0.77
43
2.00
924.12
924.12
1.03
44
2.00
924.12
924.12
1.03
45
1.90
877.91
877.91
0.98
46
1.90
877.91
877.91
0.98
SHT3OF5
DISCHARGEANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
47
1.70
785.50
785.50
0.87
48
1.80
831.71
831.71
0.92
49
2.50
1155.15
1155.15
1.28
50
2.60
1201.36
1201.36
1.33
51
2.80
1293.77
1293.77
1.44
52
' 2.90
1339.97
1339.97
1.49
53
3.40
1571.00
1571.00
1.75
54
3.40
1571.00
1571.00
1.75
55
2.30
1062.74
1062.74
1.18
56
2.30
1062.74
1062.74
1.18
57
2.70
1247.56
1247.56
1.39
58
2.60
1201.36
1201.36
1.33
59
2.60
1201.36
1201.36
1.33
60
2.50
1155.15
1155.15
1.28
61
2.40
1108.94
1108.94
1.23
62
2.30
1062.74
1062.74
1.18
63
1.90
877.91
877.91
0.98
64
1.90
877.91
877.91
0.98
65
0.40
184.82
184.82
0.21
66
0.40
184.82
184.82
0.21
67
0.30
138.62
138.62
0.15
68
0.30
138.62
138.62
0.15
69
0.50
231.03
231.03
0.26
70
0.50
231.03
231.03
0.26
71
0.50
231.03
231.03
0.26
72
0.40
184.82
184.82
0.21
73
0.40
184.82
184.82
0.21
74
0.40
184.82
184.82
0.21
75
0.30
138.62
138.62
0.15
76
0.20
92.41
92.41
0.10
77
0.30
138.62
138.62
0.15
78
0.40
184.82
184.82
0.21
79
0.30
138.62
138.62
0.15
80
0.20
92.41
92.41
0.10
81
0.30
138.62
138.62
0.15
82
0.30
138.62
138.62
0.15
83
0.30
138.62
138.62
0.15
84
0.20
92.41
92.41
0.10
85
0.30
138.62
138.62
0.15
86
0.20
92.41
92.41
0.10
87
0.30
138.62
138.62
0.15
88
0.20
92.41
92.41
0.10
89
0.30
138.62
138.62
0.15
90
0.20
92.41
92.41
0.10
91
0.20
92.41
92.41
0.10
92
0.201
92.41
92.41
0.10
SHT 4 OF 5
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
93
0.20
92.41
92.41
0.10
94
0.20
92.41
92.41
0.10
95
0.20
92.41
92.41
0.10
96
0.20
92.41
92.41
0.10
F=
1 46206.001
1
d
9
SHT 5 OF 5
0
=C=
mc:::
zm-:=
=MONO
RlL
1:31F g
RIVERSIDE COUNTY FLOOD CONTROL
AND
WATER CONSERVATION DISTRICT
10
8
6
5
4
3
2
H
LL
v
�-0
0!
W 1
Q
0.8
0
F- 0.58'0.E
0- LOT 27
W 0.°
0
0.�
0.1,
0.2
0.12'
PARCEL1
0.1
1
N
4 X 0.8 X 0.5 BLOCKAGE 4'
ro
�1=1WjENMEWAVAWFAEWZA
GRATE OPENING RATIO
P- 1-7/8-4 0.8
P- 1-1/8 0.6 IMEFWAA
Reticuline 0.8
Curved Vane 0.33
30* Tilt -Bar 0.34
* Tested
on
WANIFARAVA
rA
I&
AFA
TRY
Apo
FA
EFAWAFAMAINAPA
MAN
MA
5,1VffAVA
FJ,1,FA11
CLEAR OPENING AREA
WN04.04F)JA;
go
,1A=
2 3 4 5 6 8 10 20 30 40 50 60 80 100
2.7 CFS 6.05 CFS
PARCEL 1 LOT 27
DISCHARGE Q (FTg SEC)
GRATE INLET CAPACITY IN SUMP CONDITION
(SOURCE USDOT - FHWA - HEC -12, 1984)
l
� %j% /iiiiiii %iii %ter= `J �
/ / / Z�
\\\�
E / AT /VOf
P O \�
PIrOPOF D FALL WAL
/(SEE SHEET OR SECTION \ \
PRO SED DETENTION BASIN 7 26
727 LD
/PROPOSED PRECA�7 4" SQ. CATCH Bp4SIN —
W/ PARKWAY GRATE BROOKS OR APP D EQUAL); - -
(SEE SHEET 3 FOR D AILS) , —
/ //j ACTUAL EXISTING TOE OF MOUNTAIN- / _
PER FIELD SURVEY DATA '
/ PROPOSED 12" CCP STORM ,DRAIN
/
co
o l /loll _
P
.nC
I
GRAPHIC SCALE
(nN FEET )
1 inch = 40 fL SHEET 1
= ��\\:�// /
Zz-
/ / /,L`XISTING TOE =O�' MOUN�AIN�
TRACT MAP- <- -�
�4,',EW�,STING=TOE -`OF MOC�NTALN \ , � ,7 /ii
/PERT FIE SURVEY= DATA_ \ �� \\\ \ /I/ // / / //' / /.
PARCELI
{WTION' BAS \ \�
/��/ PROPOSED ROCK FALL WAL \ \ \ \� i I /
LL)
a �
_J \
(SEE SHEET 4 FOR SECTION
\�,� \` /i_ __ 12n CCP_ STORM BRA!' -
PROPOD_ — -
I �l
00
\\ 27
�G°�G�,Cali 287740
CE - r
/ PEERLESS -
\ rte_
-T R6POS D PR AST 4" S Q
_ -PAR WAY BRAG C
— — \ S IET F AILS
H BASIN
m m •i i m m m m m» m m m m m m m r
�1_
a
F-4
a
w I
a k
CATCH BASIN DETAIL
NTS
R/W & BACK OF CURB
PROPOSED ROCK. LL WALL -�
PROPOSED DETENTIO BASIN D=2----
6" CURB AROUND CATCH BASIN
_Typ 12" DIA CCP STORM DRAIN PIPE
I _
PROPOSED PRECAST CATCH BASIN
(BROOKS OR APPROVED EQUAL)
ACTUAL EXISTING TOE OF MOUNTAIN -�
10' pVE PER FIELD SURVEY DATA
_I I
I I
SHEET 3
� � m m m m m m r m m m m m m m m m
N
2
im
r
■
MEN
O
v
O
m
v
HT. PER ROCK FALL o
REPORT RECOMMENDATIONS
D
r
r
D
r
a
2' DETENTION
MINIMUM
0
z
R
C
m
m
x
4
z
O
O
C
z
i
z
N
a
r
r
O
V
L
ry
Q If
N
�` SL SL
yS
� R
�y
�I
ap
R � �
f
AO1 R
.4
4
b1 q
wAQ
"gFgF�
R -R
Y
h4
s
86
e €
gg�
a$
•0 a x
s a
35
I?
•
� jR
i
Ra
R
IR q fl v I
Z!
a
7z, p
�R
8di
ti4q
i
4A
v as &
R X��Jxj,
RR�R�
s °
� O
���sTDJ
k s
�� nr
2
Co
BE N
I?
•
� jR
IR q fl v I
Z!
a
7z, p
�R
8di
ti4q
i
4A
v as &
R X��Jxj,
RR�R�
s °
� O
���sTDJ
k s
�� nr
2
Co
•
� jR
Ra
IN AtE CITY OF LA OUONTA COUNTY OF elTS WE• STATE OF CALIFORNIA SHEET 2 OF 3 SHEETS
1 IVs oaxo -. N
' a sae r
AlaV—
SCALE '-'°°
LOM as a0A 0111 OTv
07 A7C7 C•1
K 11512
�A1A0.1
PARCEL MAP NO. 32891
oJDl�bt
0
50 100 200
300
ri
. :111151 11
'A)�I a'ID7AAF1 AITO�RO -r
amyl
We ,
°aT•uor �
ao�D.l
��
a
A7nrat
Mir
MSG A S08WISION OF LOT 34 OF TRACT 26611 AS 9JOW-4 IN WP BOON 269, PAGES 12 THROUGH 17, INCLUSIVE. RECORDS OF
1
Ar WV-rl
PARCEL 2
L. -
rMlrat
Ha•
RNERSIDE COLRAY STATE OF CALIFORNU 440 CIY OF U OUIJTA LOT LINE ADJUSTMENTS 99 -298 AND 99 -299 RECORDED MARCH
'i'n
aa7
yM O's
Aa71
a
nn7av
16ra71V
. PC
109f
18. 1999 AS ISTRUYEMS 112049 THRObCN 112051, DICLVShE, RECORDS OF SAID RMRSOE COUNTY.
-d— 0,0fA1Ef A SU V. NSaE DWEiR ICON PIPE, RU9A IIH P4SiC
OsK
can A7CUS iDi>r
Ikpl
4
'M1°rm
.1w
KELLEHER M"PING FEBRUARY 2006
PWD SIAaED 7LS 6667• N D2 ARM OR SU LEAD AM TAD
a
a
if 11.1 48111 Ia.r
or it elm ram•
Abu•
am
u
AID1971t
Amxln
at
, "�'>G •.
STAMM RS gar a COMRUT AREAS Alm TOP OF *MIS'JR N
DE TOP OF CL46 AT-OE PAMOAGATM O M WE LOT IVES
u
G
xalr slat xtt
Wr 1101 11x
a.Y
AOr
I
71„
WIT"
'IV
pa'
- SURVEYOR'S NOTES
W 61"Of15 lu BE SET AT FONT LOT CM*M AM ON TIE
O
01
."V.r alm A16a'
4110,1• mm raw
aa'
ua1
N'
.
lGrwxt
�sr
oI,-
Br36 OF SEAIM:
FRONT LOT LKS AT AKAL POINTS 440 POINTS OF OA'ArM VIM
SAID POWS FALL ADaCDR TO TK CONSRAM CMCF17E CM.
CI
w
a717r alit dal'
Pnrlr star ar
W.,
HAY
111
n7
rlt'"
N7r)rav
Mat
mP.'
GEARDIDS AF4 BARD 1I09N M AtJROEALT t9d Or LOT 34 Or TRACT
T14 tai COAS7f OF FARCCLS I WO 2
a
w.rtr atat att
.iF
n.
1DJe'tlY
tl1.a'
28611 Pot w BOOR M. PARS 12 THD" 17, um6vAC
A
0vx tut .Im•
P.W.
t i
Ulm
RECORDS OF RMRSDE COaTY,
IV WE DOCAM TA.OIIC UTILITY EASDIM PER TRACT 25470,-I. 10
C11
aab' I'm sat
Aur
1pvofaar
BW6 NORTH 69WW EAST
267/76 -90 AN) TRACT 28611. IS 269/12 -17.
CQ
cu
A7p'r 1II.ia' 1H.N•
1691TO• 1•r aAt
MIt
t.so'
uA
111
1AOa'l.t
Iatal'S.t
tmm9n
0.R
'LY
sat
—�..- IO I.P. �/ Pa6EC PLOD
610
/OfAM DRAWS DRUM Alt 40 BIRO AREA N PUAVN
c..
atN.f nn.+1 :pm'
Ala'
m
Aef71H
l..a'
WAP 234 0-
SET fLNSII OR AS OIIERA6E HOIW PER iR1G1 MAP 28A7D -1. 1®
SET FUIS R AS T R
PLSE•4SD 1MON.
RI
MFOnM1
021
2WG -90 OR R 25511, Y8 769/12 -17,
TOTAL YEA . I /.t7 MGM
........... ................... ............
— — DEACON DRIVE EAST— - - - - -
...
_ - - -
1 IVs oaxo -. N
' a sae r
AlaV—
mo7 AAri o7 a
aA e7io-1
vl• "� � LDIa
.� • LSrr 115
� va7A7.1 AAp
�
LOM as a0A 0111 OTv
07 A7C7 C•1
q olaal 1
a�.
�A1A0.1
.e a
oJDl�bt
7R 75740.1
ata 7
AIIOr.
SEE SHEET 3
'A)�I a'ID7AAF1 AITO�RO -r
amyl
We ,
°aT•uor �
ao�D.l
��
Mallo.
aloAlbl
ai
1
Ar WV-rl
PARCEL 2
L. -
101I.01w>+ 4ws wOna
1'0fmm"tm
'i'n
aa7
Aa71
i'll -m .w'0Fn' a W
a MT. mt lla.l a I'm
.c
1d
mo7 AAri o7 a
aA e7io-1
vl• "� � LDIa
.� • LSrr 115
� va7A7.1 AAp
�
LOM as a0A 0111 OTv
to xyp.a
q olaal 1
a�.
1
.e a
7R 75740.1
a
SEE SHEET 3
roi°a mm pawn
°aT•uor �
Pim Set N0,.
ai
1
PARCEL 2
101I.01w>+ 4ws wOna
1'0fmm"tm
'i'n
Aa71
i'll -m .w'0Fn' a W
a MT. mt lla.l a I'm
.c
a awl 1'
a `
l
T54,
abpf
, "�'>G •.
♦
�l� A•�al.��:
S1?7 ,a.li•/e:ai• A aaY Y
a wm u+
I
�i.eiil.. •' A.
PEERLESS— PUCE--
> _
1® 269/12.77 A.
LOT J?
OR Milo-,
• ' 111 a 'J% I • . AO 75J116 -9J
^�� •\ SIP,'
�a�� AN 761/76 -R7
tDF a --
ala7A7 -r 1
61aVe -ro
La7 n
� YB 76.1/76-90
�\ l
f01 10
• _ tR 76711 -1
T
107 JJ
lR 75511
LOT ii
or IWrr
rs769/17 -17
WIN
LOM as a0A 0111 OTv
to xyp.a
Y.pITi IA il't AN.W.06
4 lalW. M' wa aroa
a W. ts I'm, a tltox
1-/ LOT 97
7R 75740.1
16 767/75-90
SEE SHEET 3
CTT.,T., .+rn
Pim Set N0,.
SCALE 1' -A0'
- Lv THE OTY OF LA WNTA. COUNTY OF R1V4RSDE. S!ATE O< CAWORN9A
PARCEL MAP NO. 32891
am,
n
.alrat
u.)r(pT
SEE $NEST 2 FOR SURVEYOR'S NOTES
n
nlrlrat
m.lr
BEING A SUBON", OF LOT 31 OF TRACT 28611 AS SHORN IN HARP BOOK 269. PAGES 12 THROUGH 17, MUSNE. RECORDS Of
AND BASS OF REARING
m
arlrnt
IAIr
RFJFNSOE COUNTY. STATE OF CALIFORNIA AND CITY OF U OIFNTA LOT LINE ADJUSIYENTS 99 -298 AND 99 -299 RECORDED "0
u
m
n�•rov
mlr�
I•a'
IDilr
18. 1999 AS INSTRUMENTS 112049 THROUGH 112051, PICIVSNi. iECORDS OF SAID RNER90E COUNtt.
m
pprorpn
aW
KELLEHER MAPPING FEBRUARY 2006
oFr[ uo1
n
.lD1roT
a.1r
aJnt D¢u I>,t11} Imlr
nrort
m
�mtD•In
nn'
CI t1319r, {ply/ III•r
a.A1•
m
l o
. ru'mt
.y)rtot
bp'
>.a
O .31W
NO
!rl
to in
mJI'
.
u OfO'If oI W aJf
WITIC WIT
)D.O•
n7
pTrIf"
"'
C. uw'ir `IX Illr
I, OrIAiT EIP VW
par
••)a
111
tt•
pVNIAr
rJom
A4'
1.15S
p 0"V* 110r a.,
OW
tip
ammt
A4'
'
CJ WY4r DIW .IJr
111f
IIp
mprl"
)Or
o D>71'o' DIW am
'i. co —rlr DIW sm
Hir
W
In
Im
i0rlr)lt
Wa]•T
O)1
I1lI'
CID b1rD1' NW •101'
/).1r
n1
lmOl11)t
a.r
nI a" 1•W DJr
u)r
IID
wOprlf(
min
I.W
+•.n•
Cn Mir )l.m' )I,lr
III,
n1
use
C) wonr NW a.r
C1. 3711.4• IIpW 13.A'
ow
a3
I
D
i I1 y O
f DI F
1 ,
-0
v J1m°,r l/9 r
-0I
. DI
f
1
cn. --F_, JT,�
i 1�,IIsp1Fro. !
7
■
go
3
0
x
O
IN THE CITY OF LA QUINTA, CAUFORNIA
HYDROLOGY & HYDRAULICS REPORT
FOR PARCEL MAP 32891 ALSO
INCLUDING 27 OF TRACT 28470 -1
IN THE NE 1/4 OF SECTION 7, T6S, R7E, SBM
EISENHOWER DRIVE
AVENUE 50
AIva, t$ /
U
I'D�n
o
0
VICINITY MAP
NTS
—i:ssl,
70080 CALLE AMIGO, SUITE 101
NGINEERING
LA QUINTA, CA. 92253
(760) 771 -9993 OFFICE
N C . (760) 771.9998 FAX
CIVIL AND STRUCTURAL ENGINEERING - PLANNING - SURVEYING
t
QROF
NR
ESS /ApyN�,
cD W No. 47834 = m
LLJ
PREPARED UNDER THE DATE
Exp. 12/31/08 DIRECT SUPERVISION OF:
�� OF C ESSI SHAHANDEH - RCE 47834 - EXPIRES 12 -31 -08
ti
w
CALLE TAMPICO
s
z
o
�
�
Z
3
AVENUE 52
3
TRADITION TRAIL
yob
ITE
AIva, t$ /
U
I'D�n
o
0
VICINITY MAP
NTS
—i:ssl,
70080 CALLE AMIGO, SUITE 101
NGINEERING
LA QUINTA, CA. 92253
(760) 771 -9993 OFFICE
N C . (760) 771.9998 FAX
CIVIL AND STRUCTURAL ENGINEERING - PLANNING - SURVEYING
t
QROF
NR
ESS /ApyN�,
cD W No. 47834 = m
LLJ
PREPARED UNDER THE DATE
Exp. 12/31/08 DIRECT SUPERVISION OF:
�� OF C ESSI SHAHANDEH - RCE 47834 - EXPIRES 12 -31 -08
Lot 27 -30 and Parcel 1 Traditions Hydrology
Summary
This report and attached calculations and exhibits are prepared to address drainage and
runoff issues concerning the development for Lot 27 of Tract Map 28470 -1, and Parcel 1
of Parcel Map 32891. Copies of these maps are included in the back of this report.
These issues must be addressed prior to proceeding with construction of residential
dwellings on these parcels. This report is prepared to support the design of
improvements to be constructed to mitigate these hazards.
Site Observations
The existing building pads are comprised of engineered fill against a rocky mountainous .
embankment to the east. The proposed building pad on Parcel 1 will be constructed in
much he same manner. The primary concern for storm water runoff is not the Pads
themselves, but the mountain areas behind the pads. These areas are very rocky,
consisting primarily of decomposed granite and boulders.
An existing 18" PVC pipe for which no construction drawings can be located is shown on
the proposed Storm Drain Improvement Plans. This pipe conveys runoff from the south
side of Lot 29 into the street. Heavy debris flows from Lots 28 and 29 are reported to
adversely affect Lot 34 across the street. The recommendation for improvement will
include mitigating this current problem by removing this pipe when the mountain channel
is constructed.
Both the Engineer of Record and City Engineer have'observed that the Original Rough .
Grading Plan for the Subdivision called for a drainage channel along the back of 29 and
30 to convey mountainside runoff to the golf course basins. Because of the Adjacent
compatible grades of Lots 28 and 29, the contiguous ownership of these lots, and the lack
of cooperation of the owner or Lot 27 in improving the drainage facilities, it is proposed
to also convey the runoff from Lot 28 through the same channel, so that Drainage Area
`A' as shown on the separate hydrology covering those mountainous areas tributary to
Lots 28, 29 and 30. ,
Parcel 1, being newly created, is conditioned to provide storm drain facilities for
mountainside runoff tributary to its proposed location. Since the construction of Lot 33
blocked the proposed channel swale on the original rough grading plan, the only viable
option is to drain onto Peerless Place at the highpoint located just north of the southerly
lot line of Lot 27. There it will drain northerly along the easterly portion of the street
section to an existing catch basin near the apex of the curve as it turns west and from
there onto the Golf Course Lake.
The Geotechnical Study reports two specific hazards from the Mountainous Terrain. The
first is significant storm water runoff and erosion debris to the lots, and the second is rock
fall potential. Both of these items must be mitigated to make the Building Pads safe for
construction of residences. A Rock Fall Study has been prepared, and recommends a
basin be dug at the toe of slope with a 3' high impact wall for large boulder impacts. To
address the runoff and debris problems, it is proposed to also use this structure for storm
water detention. The 3' retaining wall will create the basis for a concrete channel on the
back of the lots to convey drainage from the mountains away from the pads and to the
golf course lakes. Further, this design will eliminate the existing 18" pipe from Lot 29 to
the street, eliminating the existing problem with debris and heavy storm flows.
Site History
The Overall Hydrology for Tract 28470 -1 included all areas, including these lots. There
are three sub -areas that are addressed in the Study. Some summary of the
recommendations of the original report and a commentary on the actual current field
observed conditions follow to help the reviewer to readily understand the drainage issues,
and understand why Essi Engineering Inc. has proposed to handle the mountainside
runoff as proposed.
The actual Pads themselves are included in Sub -area "R22" of the original study, which
is designed to sheet flow to .Peerless Place, thence down the emergency access drive and
to Basin 5. This situation is typical design for the subdivision. The Pads will be
improved with area drains and bubble boxes, which will eliminate any existing erosion
1 issues on the pads themselves, and continue to discharge to Peerless Place. Therefore,
this area has not been included in the study.
The mountainous areas immediately behind the lots are part of Sub -area "012" in the
initial study. This area was originally designed to drain to a graded swale channel at the
toe of the slope. This design feature is clearly indicated in the routing of the Hydrology
in the Report, on the Offsite Hydrology Map (Included) and on the original Rough
Grading Plan. However, the improvements were not constructed in this fashion. Field
observations reveal the channel is not graded. Grading has not been performed in a
fashion that would allow a channel to be constructed and interconnected. No easements
exist to install any such channel, and now that lots have been sold, property owner
cooperation to record them is difficult to obtain.
Rerunning the calculations with the correct tributary areas and correct runoff coefficients
yields significantly larger runoff and storage requirements than were previously
anticipated. Our goal then is to prepare the best possible mitigation plan for the existing
conditions without severely limiting the building envelope for the already permitted
residential land use of Lots 27 and Parcel 1.
r
The reviewer should thoroughly study the original Offsite Hydrology Map, Master
Hydrology Map, October 1996 TKC Hydrology Report and Calculations for Traditions
Country Club, and the Original Grading and Street Improvement Plans prepared by TKC
when reviewing the findings of this report. Copies of all of these documents with
comments are being submitted with this report, and all of these records are incorporated
,, by reference.
Therefore, these mountainous areas which are tributary to all these lots are the greatest
cause of concern. Further complicating the problem, the topography used in- the original
study is incomplete. The Master Hydrology Map shows contours for these Mountainous
areas only up to an elevation of 200 feet. The Offsite Hydrology Map used a USGS
Quad Map that clearly shows the ridge line in these areas is further east, and extends to
An elevation of over 400 feet. For calculations to be accurate, the values used for area
1
and slope must extend all the way to the ridge line. Since the topography is incomplete,
and the areas in error on the October 1996 Hydrology Study and Map, USGS quad sheets
and shadow analysis on aerial photographs has been used to identify the ridge and its
'
elevations, and used to augment the existing DTM model, for the purpose of modeling
the runoff. RCFCD Manual Plate E -1.1 Sheet 1. of 6, A.1 states that a USGS quadrangle
is an acceptable topography map to model the runoff from, so we have used this option
instead of the more costly option of a new aerial survey. Since the original, and correctly
delineated Offsite Areas were prepared on the Original Offsite Hydrology Map for the
entire subdivision, this is the best way to correctly model the Site for comparison to the
existing prepared studies as well.
Rerunning the calculations with the correct tributary areas and correct runoff coefficients
yields significantly larger runoff and storage requirements than were previously
anticipated. Our goal then is to prepare the best possible mitigation plan for the existing
conditions without severely limiting the building envelope for the already permitted
residential land use of Lots 27 and Parcel 1.
r
The reviewer should thoroughly study the original Offsite Hydrology Map, Master
Hydrology Map, October 1996 TKC Hydrology Report and Calculations for Traditions
Country Club, and the Original Grading and Street Improvement Plans prepared by TKC
when reviewing the findings of this report. Copies of all of these documents with
comments are being submitted with this report, and all of these records are incorporated
,, by reference.
1 /
' Riverside County Hydrology Manual of 1978 —
Soils Type:
The Hydrologic Soils Type per the Riverside County Hydrology Manual is
"Group D"
Quotation from the RCFCD Manual Page C -2: "Group D — High runoff potential.
Soils having very slow infiltration rates when thoroughly wetted and consisting
chiefly of clay soils with a high swelling potential, soils with a permanent high
water table, soils with a clay pan or clay layer at or near the surface, and shallow
soils over nearly impervious material. These Soils have a very slow rate of Water
Transmission."
' Soil Cover Type:
The soil cover is poor, as with most desert mountainous areas, there is little to no
plant coverage to protect the ground from erosion and absorb runoff.
Quotation from RCFCD Manual Page C -3: "Poor — Heavily grazed or regularly
burned areas. Less than 50% of the ground surface is protected by plant cover or
brush and tree canopy."
AMC — Antecedent Moisture Condition
1 An AMC number of AMC II has been used for this property.
RCFCD Manual Quotation of Page C -4: "AMC II — Moderate Runoff Potential,
an intermediate condition." "For the purposes of design hydrology, using district
methods, AMC 11 should normally be assumed for both the 10 year and 100 year
frequency storm.
Runoff Index Number and Coefficient of Runoff (Rational Method "C" variable):
Per RCFCD Manual Plate D -5.5 Sheet 1 of 2, The runoff index for Soil "Group
D ", Natural Covers, Barren (Rockland, eroded and graded land) is 93. This is
toward the higher end of the table. The runoff coefficient curve for these variable
results in a C value for the Rational Equation of 0.9. However, due to the
disputed nature of the drainage issue, we shall make no adjustments for any losses
in the studies as presented.
Rainfall Data Source:
Included within this report is the rainfall data generated from the National Oceanic and
Atmospheric Administration (NOAA) Atlas 14 Version 4 charts for both 6 Hour 100
Year and 24 Hour 100 Year storms. The city of La Quinta in their Engineering Bulletin
#06 -16 dated 1/29/07 provides for certain datum to be used for a particular area within
the City's limits. Lot 27 and Parcel 1 lay within Zone 4. However, this study is for the
mountainous area above these properties and lay within Zone 3. storm values in this zone
are;
1 hour : 2.20 ", 3 hour : 2.80 ", 6 hour : 3.40" and 24 hour : 4.50"
All the hydrographs reflect the use of these intensities.
Tributary Areas Synthetic Unit Hydroarauh (Short Method):
Watershed B
Area B -1 is tributary to Parcel 1 and consists of 1.14 Acres of Mountainous
Terrain.
Area B -2 is tributary to Lot 27 and consists of 2.84 Acres of Mountainous
Terrain.
At the base of the mountain we proposed a detention basin be built using the required
r6ck -fall wall as an integral part of the basin. The basin shall be constructed to provide a
depth of two feet of storage. As the storm progresses, the basin fills to a point that flows
can be captured by a pre -cast concrete catch basin two foot square with a parkway grate.
This grate provides adequate support since it will be out of the traffic areas. Charts
demonstrate that the basin performs under the maximum Qioo at time period 15 of the 3 -.
hour 100 year storm for Lot 27. This is the worst case for all the periods analyzed for any
of the storms for both parcels.
FINDINGS AREA B -1:
' Area B -1 has the best performance as to storage, providing 8,404 cubic feet. While
smaller than that provided by B -2, its tributary area is much smaller. After careful
1 analysis of the 3, 6 and 24 hour 100 year storms we find that area B -2 overflows the
detention basin at later points in the storm
1 Discharge for the 3 -hour, 100 year storm is begins at period 15 and reaches a
maximum of 2.71 c.f.s. at period 16. Each of these periods has is of 10 minutes.
1 Discharge for the 6 -hour, 100 year storm never occurs. The proposed basin
provides adequate capacity for this storm. .
Discharge for the 24 -hour, 100 year storm is begins at period 45 and reaches a
maximum of 0.70 c.f.s. at period 53. Each of these periods is a duration of 15
minutes.
FINDINGS AREA B -2:
After careful analysis of the 3, 6 and 24 hour 100 year storms we find that area. B-2
overflows the detention basin at later points in the storm.
'
Discharge for the 3 -hour, 100 year storm is begins at period 11 and reaches a
maximum of 6.08 c.f.s. at period 15. Each of these periods is a duration of 10
minutes.
Discharge for the 6 -hour, 100 year storm is begins at period 19 and reaches a
maximum of 2.84 c.f.s. at period 22. Each of these periods is a duration of 15
minutes.
Discharge for the 24 -hour, 100 year storm is begins at period 34 and reaches a
maximum of 1.75 c.f.s. at period 53. Each of these periods is a duration of 15
minutes.
I11
Final Recommendations and Observations
The Channel and Rock fall need to be constructed as shown on the prepared Grading
Plans for the lots, and per the structural details and recommendations of the Geotechnical
Report. The Storm Drain improvements should be adequate to convey all tributary
mountainside runoff from Watershed B, provided the structures are constructed per this
analysis.
If the recommendations of this report are followed, and the improvements are constructed
'
per the Plans prepared by this office, the hazards from storm water runoff will be
mitigated and the existing issues with the debris flow from the parcels to the street will be
eliminated.
Essi Shahandeh, Civil Engineer Date
' R. C. E. 47834, Expires 12/31/08
70 -080 Calle Amigo, Suite 101
' La Quinta, Ca. 92253
(760)771 -9993 Office — (760)771 -9998 Fax
33.650000 N 33.66667° N 33.6:33' N
�A
A
`< JP
D n
Zv
D
r
r
I
m
0
i
C71
N
0
N
RUNOFF COEFFICIENTS FOR RI INDEX NO. s 92
IMPERVIOUSI INTENSITY - INCHFS /HOUR
PERCENT
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
5.
10.
I5.
20.
25.
30.
35.
40.
45.
50.
55.
60.
65.
70.
75.
80.
85.
90.
95.
100.
.00 .73 .81 .84 .85 .86 ,R7 .87 .87 .88 .88
.04 .74 .81 .84 .85 .86 .R7 .87 .88 .88 .88
.09 .75 .82 .84 .96 .86 .87 .P7 .88 .88 .88
.13 .76 .82 .85 .A6 .87 .A7 Be . .88 .88 .89
.18 .76 .83 .85 .A6 .87 ,617 AS Be , .88 .89
.22 .77 ,83 as .A6 .87 AT AS .88 .88 .89
.27 .78 ,A3 .85 .97 .87 .8A .AA .88 .89 .89
.31 .79 ,84 .86 .87 .87 .88 .89 .88 •89 .89
.36 .80 .84 .86 .A7 .8A .8A .88 .88 .89 .89
.40 .81 .85 .86 .87 .018 .AA .88 .89 .89 .89
.45 .82 .85 .87 .88 .98 .AA .89 .89 .A9 .89
.49 .82 .86 .87 .AA .88 .AA ,A9 .A9 .A9 .89
.54 .83 .86 .97 .48 AS ,A9 .89 .89 .89 .89
.58 .84 .87 .88 .88 .89 .A9 .89 .89 .89 .89
.63 .85 .87 .88 .A9 .89 .A9 .89 .89 .89 .89
.67 .86 .88 .88 .A9 .89 .89 ,A9 .A9 .89 .90
.72 .87 .88 .89 .89 .R9 .89 .89 .89 .90 .90
.76 .87 .A9 .89 .89 .89 .89 .90 .90 .90 .90
.81 .88 .89 .89 .90 .90 .90 .90 .90 .90 .90
.86 .89 .90 .90 .90 .90 .90 .40 .90 .90 .90
,90 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
RUNOFF COEFFICIENTS FOR RI INDFX NO. = 96
RUNOFF COEFFICIENTS FOR RI INDEX NO. = 94
1MPERVIOUSI INTENSITY - INCHFS /HOUR
PER
.0 .5 1.0 I.5 2.0 2.5 3.0 3.5 4.0 5,0 6.0
0.
S.
10.
15.
20.
25.
30.
35.
40.
45.
50.
55.
60.
65.
70.
75.
R0.
85.
90.
95.
100.
IMPERVIOUS INTENSITY - INCHES/HOUR' I IMPERVI
PERCENT PERCENT
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
0.
S.
10.
15.
20.
25.
30.
35.
40.
45.
50.
55.
60.
65.
70.
75.
80.
85.
90.
95.
100.
.00 .81 as .87 .88 .88 .BA .89 .89 .89 .89
.04 .81 .85 .87 ,AA .88 AS .89 .89 .89 .89
.09 .82 .86 .87 .88 '.88 .89 .89 .89 .89 .89
.13 .82 .86 .87 .88 .88 .89 .89 .89 .89 .89
.16 .83 .86 .87 .88 .88 .439 .89 .89 .89 .89
.22 .83 .86 .98 .88 .89 .A9 .89 .89 .89 .89
.27 .84 .87 .88 AS .99 .89 .A9 .89 .89 .89
.31 .84 .87 .88 .88 .89 .89 .89 .89 .89 .89
.36 .85 .87 .88 .89 .89 .89 .89 .89 .89 .90
.40 as .87 .88 .A9 .89 .A9 .89 .89 .89 .90
.45 AS .88 .88 .89 .89 .A9 .89 .89 .90 .90
.49 .86 .88 .89 .89 .89 .99 .89 .89 .90 .90
.54 .86 .88 .89 .A9 .89 .89 .89 .90 .90 .90
.58 AT .88 .89 .89 .89 .A9 .90 . .
90 .90 .90
.
.63 .87 .89 .89 .89 .89 .90 .90 90 90 .90
.67 .88 .89 .89 .89 .90 .90 .90 .90 .90 .90
.72 .88 .89 .89 .90 .90 .90 .90 .90 .90 .90
.76 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.81 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
.86 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
.90 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
0.
S.
10.
15.
20.
25.
30.
35.
40.
45.
50.
55.
60.
65.
70.
75.
80.
85.
90.
95.
100.
.00 .77 .83 AS .A6 .87 .8A .88 .88 .88 .89
,04 .78 .83 .85 .47 .87 .RR .88 .88 .89 .89
.09 .78 .84 .86 .87 ,87 .88 .88 .88 .89 .89
.13 .79 .84 .86 .87 .67 .88 AS .88 .89 .89
.18 .80 .84 .86 .87 .88 .AA .88 .89 .89 .89
.22 .80 .85 .86 .87 .88 .88 .A8 .A9 .89 .89
.27 .81 AS .97 .87 .88 .88 .99 .89 .89 .89
.31 .81 .85 AT .88 .88 .SA .99 .89 .89 .89
.36 .82 .86 .87 .A8 .88 .R9 .89 .89 .89 .89
.40 .83 .86 .87 .89 .88 .A9 .89 .89 .89 .89
.45 .83 .86 .98 OR .89 .99 .89 .89 .89 .89
.49 .84 .87 .88 .88 .89 .89 .89 .89 .89 .89
.54 .85 .87 .88 .89 .89 .89 .89 .89 .89 .89
.58 as .88 Be . .89 .89 ,A9 .89 .89 .89 .90
.63 .86 .88 .A9 .89 .89 .89 .89 .89 .90 .90
.67 .87 .88 .89 .159 .89 .R9 .89 .90 .90 .90
.72 .87 .89 .89 .R9 .89 .90 .90 .90 .90 .90
.76 .86 .89 .89 .89 .90 .90 .40 .90 .90 .90
.81 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.86 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
.90 .90 .90 ,90 .90 .90 .90 .00 .90 .90 .90
RUNOFF COEFFICIENTS FOR AT INDEX NO. - 98
INTENSITY - INCHES /HOUR
.0 .5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0 6.0
.00 .85 .88 '.88 .A9 .69 .89 .89 .89 .90 .90
.04 .86 .88 .88 .89 .89 .89 .89 .89 .90 .90
.09 .86 .88 .89 ,A9 .89 .89 .A9 .89 .90 .90
.13 .86 .88 .89 .89 .89 .89 .89 .89 .90 .90
.18 .86 .68 .89 .89 .89 .A9 .89 .90 .90 .90
.22 .87 .88 .R9 .89 .89 .89 .89 .90 .90 .90
.27 .87 .88 .89 .89 .89 .A9 .90 .90 .90 .90
.31 .87 .8B .89 .A9 .89 .R9 .90 .90 .90 .90
.36 .87 .89 .89 .89 .89 .90 .90 .90 .90 .90
.40 .87 .89 .89 .A9 .89 .90 .90 .90 .90 .90
.45 .88 .89 .89 .89 .90 .90 .90 .90 .90 .90
.49 .88 .89 .89 .A9 .90 .90 .90 .90 .90 .90
.54 .88 .89 .89 .90 .90 .90 .90 .90 .90 .90
.58 .88 .89 .89 .90 .90 -.90 .90 .90 .90 .90
.63 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.67 .89 .89 .90 .90 .90 .90 .90 .90 .90 .90
.72 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
.76 .89 .90 .90 .90 .90 .90 .90 .90 .90 .90
.81 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
.86 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
.90 .90 .90 .90 .90 .90 .90 .90 .90 .90 .90
O
cr-
O
Z
W
U N
W
0.
Z
_I g
Z
o
w v
x
.i
f�
W
Q
Z
_
Q cr
cr O
V I
cr
D
O
ii
iO
w 0 N O m P 1 1 n n h O O N I n P P 1 1 n n N N N 1 1 1 n N n I n N n n n N n N n N n N N N N N N N
O W
•• 6
O
6 ♦NNNNN111N NN N000000000OhhhhhhhhhhmmmmmmmmmmPPPPPPP
- W
n
e°
aW rrr
Dp
I Q •••• r- .. r r r r� N N N n n n 1 n 1 n n N N O 1 N N 1 n• .-
>W
76
� O
Q • • • • • • • . • • • • • • • • • • • • - - - - - - r - - r r N N N - - N N - - r -
1W
•p
°
[w rNn. �NOhmPOrNnINOhmPO- NnIN�OhmPO.+NnINOhOPO.- Nn�NOhm
'W --- - - - - -- .•• N N N N N N N N N N n n n n n n n n n n 1 1 1 1 1 1 1 1
.p
Z•°• hmPO : :Nn11 NO ;OpNhOPPONnN
1111u rrNNNhNNN NNnnn11N-
°
0
i•+ 00- NnlNehm POrNnINOhmPO -N
► W
6
Z•°• OnmPnOmeO ♦�♦
np n111NNOP -jN♦ '
� zo
�« hP -N :1 :NOhmONOnhINPN�CN10
YIW rNNNNNNNNNnnnllN l'Q•�e
wp
nil—
Z2 - N n 1 1 N 0 e 0 0 e h h O m m 0 0: N N O O N N P N N m-
o Q -- r- - - -- r r r r r N N N N N N n n ........
z°
I« N 0 0 0 O h h h h h h m m m m m m m m m m m m P m P P P P P P P 0 It 1! r r N n 1 1 N N 0 0
N W - - - - - - - - - - r - - - ^ -
s
°
.4 1
h W
6
z .°.
bQ
nn
iE
1 Q
OW
-s
�O
7Q
eo
IQ'
•W
6
N N
m rPOn10 n.0 -N
7 I N I O h p P N h 0 1
N-
I N n n n n 1 1 N N O N h m 1 1 n N
in -NYam YImmNOmNNNOOh1hn- POrNeNmnNPOOmO
.- - - -- r -- r- r N N N N N N N N n n N n n I N n O h m N N r r
RCFC a WCD
HYDROLOGY 1N /JANJAL
^ ^ ^- �' - - ^- •� N N N N N N N N N n n n n n n n
M
0�
N
d
Q
E
CL
d
N M
o�
E M
N N
� t
d
C p
7
f
w
O O
E
O C
O N
'O
C �
d C
t C
0
C CP
O C1
v r
d
N O
0
f/1 �
N
y` a
`o c
a
� f
Q
t n
1 �
co i
Q
C t
O
M N
W = N
F-
O
Z
PLATE E-5.9
RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL -COVER COMPLEXES FOR PERVIOUS AREAS -AMC II
Cover Type (3)
Quality of
Cover (2)
Soil Group
A
B
C
D
NATURAL COVERS -
Barren
78
86
91
93
(Rockland, eroded and graded land)
Chaparrel, Broadleaf
Poor
53
70
80
85
(Manzonita, ceanothus and scrub oak)
Fair
40
63
75
81
Good
31
57
71
78
Chaparrel, Narrowleaf
Poor
71
82
88
91
(Chamise and redshank)
Fair
55
72
81
86
Grass, Annual or Perennial
Poor
67
78
86
89
Fair
50
69
79
84
Good
38
61
74
80
Meadows or Cienegas
Poor
63
77
85
88
(Areas with seasonally high water table,
Fair
51
70
80
84
principal vegetation is sod forming grass)
Good
30
58
72
78
Open Brush
Poor
62
76
84
88
(Soft wood shrubs - buckwheat, sage, etc.)
Fair
46
66
77
83
Good
41
63
75
81
Woodland
Poor
45
66
77
83
(Coniferous or broadleaf trees predominate.
Fair
36
60
73
79
Canopy density is at least 50 percent)
Good
28
55
70
77
Woodland, Grass
Poor
57
73
82
86
(Coniferous or broadleaf trees with canopy
Fair
44
65
77
82
density from 20 to 50 percent)
Good
33
58
72
79
URBAN COVERS -
Residential or Commercial Landscaping
Good
32
56
69
75
(Lawn, shrubs, etc.)
Turf
Poor
58
74
83
87
(Irrigated and mowed grass)
Fair
44
65
77
82
Good
33
58
72
79
AGRICULTURAL COVERS -
Fallow
76
85
90
92
(Land plowed but not tilled or seeded)
c
R C F C a W C D RUNOFF INDEX NUMBERS
HYDROLOGY NIANUAL FOR
PERVIOUS AREAS
PLATE E-6.1 0 of 2)
M M M M M M M M M M M M M M M M M = M
494.,rm A %t" I, �, j s \- r* !,- rl�l r -YTI�-,� - , , r',� , , I SF)AifN I
35-N -
KING AN
A/
BARSTQ 35 °N
46 t
�d
,4, � E�TYNINE PALMS'�n
34'N
PRI�[Q S�
BLYT
x
33'N
k10 ZUMA
ND' 33'N
XL CENT 1') YUM
....... MEXICO .. ... .
32*N-
(AJO
32'N
120*W 119*w 118*w 117'W 116 °W 115 °W 114-w 113*W
SOUTHEASTERN CALIFORNIA
NOAA Atlas 14, Volume 1, Version 4 Inches
Semiarid Southwestern United States Isopluvials of 6 hour precipitation (inches) LJ' 1.22 - 1.40 ❑2.01 - 2.20 2.81 - 3.00 4.51 - 5.00 ❑6.51 - 7.00
' I - Prepared by U.S. DEPARTMENT OF COMMERCE SCALE 1:2,000,000 with Average Recurrence Interval of 100 years - 3.50 5.01 - 5.50 7.01 - 7.50
4 (when pfinte&ie� at ANSI C size) 1.41 - 1.60 ❑ 2.21 - 2.40 E] 3.01
N WEATHER SERVICE o to 20 30 4G 50
NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION
NATIONAL
OF'FICE OF HYDROLOGIC DEVELOPMENT - - Wes See NOAH Atlas 14 documentation for factors to 1.61 - 1.80 2.41 - 2.60 3.51 - 4.00 5.51 - 6.00 7.51 - 8.00
YD
H ROMETEOROLOGICAL DESIGN STUDIES CENTER 0 510 20 30 40 50 60 7D convert to Annual Exceedance Probabilities for 1.81 -2.00 2.61 - 2,80 4.01 -4.50 6.01 -6.50
June 2006 Kd-t- all estimates below 25 years c°nron,ar C-, D-1 w,o- St-,d P,,�, 3e �d 45 G,n- -d., 112.
hrcY a tli�
� I
E
;k
yg�
l/
i
r
_.� j�
u
17
m
07
Cl
m m
m m
r 77,
Precipitation Frequency Data Server Page 1 of 3
POINT PRECIPITATION 4e
FREQUENCY ESTIMATES���a
' FROM NOAA ATLAS 14
California 33.66922 N 116.29036 W 141 feet
from "Precipitation- Frequency Atlas of the United States" NOAA Atlas 14, Volume I, Version 4
I' G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland, 2006
Extracted: Wed May 21 2008 -data Limits I Seasonality 1 Location Maps I;' Other Info. (, 5s data 11,11 Maps I_ Help I; D oocs Ij� Umap
Precipitation
Frequency Estimates (inches)
(Years)
min
min
min
0.40
min
min
3 hr
(fir
1.06
s
h
dAY
F&I
1.47
20
d
30
45
Q
�1
0.10
Efl
0.19
E2fl
0.32
OF447
0.51
0.68
0.84
0.89
El Fo 9-61
Efl
Kfl
1.26
1.41
1.59
1.68
�2
0.14
0.21
0.26
0.36
0.44
0.59
0.69
0.92
1.13
1.21
1.23 1.30
1.44
1.54
1.73
1.93
2.18
2.30
�5
0.22
0.34
0.42
0.56
0.70
0.91
1.04
1.37
1.68
1.83
1.84 1.95
2.15
2.31
2.61
2.90
3.27 3.47
F10-1
0.29
0.45
0.56
0.75
0.93
1.19
1.34
1.73
2.10
2.31
2.31 2.47
2.71
2.92
3.29
3.64
4.10 4.35
F25-1
0.41
0.63
0.78
1.05
1.30
1.62
1.80
2.25
2.70
3.00
3.03 3.24
3.52
3.80
4.26
4.69
5.24 5.58
50
0.52
F6_801
0.99
EE
1.65
2.01
2.19
2.71
3.19
3.58
3.64 3.88
4.19
4.53
5.05
5.53
6.14 6.55
100
0.65
0.99
1.23
1.66
2.05
2.46
2.64
3.20
3.73
4.19
4.32 4.61
4.92
5.33
5.91
0
7.09 7.58
200
0.81
1.23
1.52
2.04
2.53
2.98
3.16
3.75
4.30
4.87
5.07 5.40
5.71
6.19
6.83
7.39
8.08 8.65
500
1.05
1.60
1.98
Efl
3.30
3.80
3.96
4.57
5.14
5.85
6.19 6.59
6.87
7.45
8.14
8.75
9.46 10.15
1000
1.27
1.94
2.40
3.23
4.00
4.53
4.66
5.27
5.84
6.66
7.15 7.59
7.83
8.51
9.23
9.85
10.55 11.34
I ' These precipitation frequency estimates are based on a partial duration sedes. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting forces estimates near zero to appear as zero.
u
* Upper bound of the 90% confidence interval
Precipitation Frequency Estimates (inches)
ARI ** ❑5 [4715IF-31, 60 120 3❑[hr 6 12 Mh 48 ❑4 ❑7 10 20 30 45 60 (years) min mm mm mm mm hr hr hr day day day day day day day
�1
O.13
0.20
0.24
0.33
0.40
0.54
0.62
0.83
1.01
1.06
1.06
1.12
1.23
1.31
1.47
1.63
1.83
1.93
�2
0.18
0.27
0.34
0.45
0.56
0.74
0.84
1.11
1.36
1.44
1.46
1.52
1.67
1.78
2.01
2.23
2.52
2.65
0
E2fl
0.43
0.53
0.71
0.88
1.12
1.27
Efl
2101
2.17
2.19
2.28
2.50
2.67
EE
3.35
3.77
3.99
10
0.37
0.56
0.70
0.94
1.16
1.46
1.63
2.08
2.51
2.74
2.77
2.89
3.14
3.38
3.80
4.21
4.72
5.00
25
0.51
0.78
0.97
1.31
1.62
1.98
2.18
2.72
3.23
3.56
3.60
3.79
4.08
4.39
4.92
5.42
6.04
6.42
F-50-]FO-6-51
.0.99
3.50
1.23
1.65
2.04
2.45
2.65
3.26
3.83
4.24
4.25
4.56
4.86
5.23
5.84
6.40
7.09
7.55
100
0.81
1.23
1.52
2.05
2.54
2.99
3.20
3.87
4.48
4.98
5.05
5.42
5.74
6.17
6.84
7.47
8.22
8.76
200
0.99
1.51
1.88
2.53
3.13
3.63
3.85
4.54
5.19
5.79
5.95
6.39
6.69
7.21
7.94
8.64
9.41
10.02
500
1.30
1.98
2.46
3.31
4.09
4.66
4.86
5.57
6.22
6.99
7.31
7.85
8.12
8.73
9.53
10.31
11.10
11.82
1000
1.59
2.41
2.99
4.03
4.99
5.59
5.75
6.46
7.13
8101
8.49
9.11
9.31
10.03
10.88
11.69
12.45
13.28
' 1 ne upper sauna m me wmroenue romrvai at eux wnnaence ievei is me value wmcn ow in me srmwarea quanuie values ror a given rrequency are greater man.
These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval.
Please refer to the documentation for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
I,,
* Lower bound of the 90% confidence interval
Precipitation Frequency Estimates (inches)
FAR[**] 5 10 15 30 60 120 3 6 12 24 48 4 7 10 20 30 45 60
(years) min min min min min min hr hr hr hr hr day day day 11 day day day day
�1
0.08
0.12
Efl
0.21
0.26 1
0.36
0.42
0.56
0.70
0.74 Efl
0.83
0.92
0.97
1.09
1.23
1.37 1.45
2F
0.11
0.17
0.21
0.29
0.35
0.49
0.57
0.76
0.94
1.01 1.06
1.12
1.24
1.32
1.48
1.67
1.88 1.98
0
0.18
0.27
0.34
0.45
0.56
0.75
0.86
1.13
1.39
1.52 1.57
1.68
1.84
1.98
2.24
2.51
2.82 2.98
10
0.23
0.36
0.44
0.59
0.74
0.97
1.10
1.42
1.73
1.92 1.98
2.11
2.32
2.50
2.81
3.14
3.52 3.72
F257
0.32
0.49
0.61
0.82
1.01
1.30
1.46
1.84
2.20
2.47 2.57
2.75
2.97
3.22
3.61
4.01
4.47 4.74
50
0.40
0.61
0.76
1.02
1.26
1.59
1.75
2.18
2.59
2.92 3.05
3.26
3.50
3.80
4.25
4.71
5.22 5.53
100
0.49
0.75
0.93
1.25
1.54
1.90
2.09
2.55
2.98
3.40 3.58
3.82
4.08
4.43
4.92
5.44
5.99 6.35
F20-0-1
0.59
0.90
1.12
1.50 I
1.86
2.26
EE]
3.41
3.92
4.14
4.42
4.67
5.09
5.64
6.18
6.78
7.18
500
0.75
1.14
1.41
1.90
2.35
2.80
2.99
3.52
4.00
4.63
4.96
5.28
5.52
6.01
6.62
7.22
7.84
8.32
1000
0.88
1.34
1.67
2.24
2.78
3.26
3.44
3.99
4.47
5.20
5.63
5.99
6.20
6.78
7.40
8.04
8.65
9.22
i ne rower oouno in me connaence moervai at yu ro connaence ievei is me value wmcn a m or me simmatea quanaie vanes ror a given rrequency are less man.
Ihttp:// hdsc. nws. noaa. gov /cgi- bin/hdsc/buildout.perl? type =pf& units =us &series =pd &statename= SOUTHE... 5/21/2008
' Precipitation Frequency Data Server
These precipitation frequency estimates are based on a partial duration maxima series ARI is the Average Recurrence Interval.
Please refer to the docum n ttgn for more information. NOTE: Formatting prevents estimates near zero to appear as zero.
' Text versic n of tables I
Partial duration based Point Precipitation Frequency Estimates - Version: 4
33.66922 N 116.29036 W 141 ft
1 2 3 4 5 6 7 8 910 20 30 40 50 80100 140 200 300 500 700 1000
Average Recurrence Interval (years)
Wed May 21 13:12:03 2008
Duration
5 -min - «- 48 -hr -x- 30-day -i�-
10 -min -+- 3 -hr -Ix- 4 -day - - --
15 -min —I— 6-hr- 7 -day -+- 60 -day -xr--
30-min -e- 12 -hr -I- 10 -day -+-
60 -min 24 -hr -e- 20-day-s-
Partial duration based Point Precipitation Frequency Estimates - Version: 4
33.66922 N 116.29036 W 141 ft
' Average Recurrence Interval
(years)
I
2 -ff- 100 —
10 -a- 500 -+-
25 -- 1000 -e-
Maps -
' http:// hdsc. r. ws. noaa.gov /cgi- bin/hdsc /buildout. erl ?t e= f &units =us &series= d &statename= SOUTHE
P YP P P
Page 2 of 3
5/21/2008
C
C C
C C E
L L
L L L L L
L L
7� M ✓1
7-
T
a T
7t
T T
E
E E E
I
E a m
t S
I I
t L -C S S
I i 1 I I
L C
I I
N N N
"1 V a
N
a
N
a
N N
'a .a
M
N 0
1
I I
m
I I N
m m
Ih 7
U) Co N CP 7
N
UI aD
f9 V
I I I
(7 Q a7
n
I
m
I I
N m
I
m
I I
In m
-" �''�
`D 0`
Duration
�+
-� N
M
v .n
Wed May 21
13:12:03 2008
' Average Recurrence Interval
(years)
I
2 -ff- 100 —
10 -a- 500 -+-
25 -- 1000 -e-
Maps -
' http:// hdsc. r. ws. noaa.gov /cgi- bin/hdsc /buildout. erl ?t e= f &units =us &series= d &statename= SOUTHE
P YP P P
Page 2 of 3
5/21/2008
' Precipitation Frequency Data Server
L
u
116.4'"W 11 15.3"w lir.7"w
Other Maps/Photographs -
7n ~W
These maps were produced using a direct map request from the
U.S. Census Bureau Mapping and Cartographic Resources
Teer MAp Server.
Please read disclaimer for more information.
z
u-
z
a
z
c
M
LEGEND
— State — Connector
- - County ? Stream
Indian Resv Militarw Area
Lake/Pond/Ocean Nationa Park
— Street an Other Park
Expressway City 11
Highway .0 .2 C.Runty.6 .8 mi
Scale 1:228583 z s
n SO i*average- true scale torreso uton
Page 3 of 3
' View USGS digital ortho hp oto quadrangle (DOOj covering this location from TerraServer; USGS Aerial Photograph may also be available
from this site. A DOQ is a computer - generated image of an aerial photograph in which image displacement caused by terrain relief anc camera tilts has been removed. It
combines the image characteristics of a photograph with the geometric qualities of a map. Visit the USGS for more information.
' Watershed /Stream Flow Information -
Find the Watershed for this location using the U.S. Environmental Protection Agency's site.
Climate Data Sources -
Precipitation frequency results are based on data from a variety of sources, but largely NCDC. The following links provide general information
about observing ,� ites in the area, regardless of if their data was used in this study. For detailed information about 'he stations used in this study,
' please refer to our documentation.
Using the National Climatic Data Center's(NCDC) station search engine, locate other climate stations within:
.. ...OR...> -u, of this location (33.66922/-116.29036). Digital ASCII data can be obtained directly from NCDC.
Find Natural Resources Conservation Service (NRCS) SNOTEL (SNOwpack TELemetry) stations by visiting the
Western Regional Climate Center's state- specifc SNOTEL station maps.
Hydrometeorological Design Studies Center
DOC/NOAA/Nationa Weather Service
' 1325 East -West Highway
Silver Spring, MD 20,)10
(301) 713 -1669
Questions ?: HDSC Ou.sdon.&a noaa ¢ov
Disclaimer
I http:// hdsc. rws. noaa.gov /cgi- bin/hdsc /buildout. erl ?t e= f &units =us &series= d &statename= SOUTHE.
P YP p p
5/21/2008
P.O. Box 1504
LA QUINTA, CALIFORNIA 92247- 1504 PUBLIC WORKS /ENGINEERING DEPARTMENT
78 -495 CALLE TAMPICO (760) 777 -7075
LA QUINTA, CALIFORNIA 92253 FAX (760) 777 -7155
ENGINEERING BULLETIN #0.6 -16.
Corrected 1/29/07
TO: Q..All Interested Parties
FROM: ` Director/City Engineer
timothy R. Jonasson, Public Works
�. .. Y En 9
EFFECTIVE DATE: December 19, 2006
SUBJECT: Hydrology Report with Preliminary Hydraulic Report Criteria for
Storm Drain Systems
This bulletin establishes storm drain study specifications. All hydrology and
preliminary hydraulic reports for the City of La Quinta should follow these criteria.
Hydrology studies for the City of La Quinta shall be performed for projects when
required by the conditions of approval or as requested by the City Engineer.
Reference material used for city plan checking purposes is as follows:
1. Plan Check Checklist
Storm drain plan checks are guided by the documents. found in the following
hyperlink:
htto:// www. la- guinta.orn /oublicworks /tractl /z onlinelibrary /olancheck. checklist %20NEW.htm,
2. Archive Plans
Example City plans can be found at the following hyperlink.-
http://www.la-quinta.org/plancheck/m—search.ast)
A useful method of quickly searching archive plans is to load the plan type and
current year (e.g. 2006) and then search the archive by clicking the GO button.
3. Hydrology Reports
All hydrology reports shall follow the general guidelines set forth by Riverside
County Flood Control (RCFC) and Water Conservation District's Hydrology Manual.
4. Hydraulic Report Guidelines (General)
Hydraulic reports shall follow the guidelines set forth by either Riverside County
Flood Control Hydrology Manual or Federal Highway Administrations FHWA HEC-
' 22 "Urban Drainage Design Manual," The developer engineer's hydraulic report is
required with the storm drain submittal but can be submitted earlier with the rough
grading submittal. Street plans must have an accompanying hydraulic report. The
' hydraulics for the project will be reviewed and approved only with the street plans.
STORMCAD or equivalent commercially available hydraulic programs are acceptable
I for hydraulic calculations. Hydraulic program data and resultant calculations must
relate to Riverside County Flood Control Hydrology Manual design guidance.
I 5. Use of Rational Method (Catch Basin Sizing) and Synthetic Unit Hydrograph
(Retention Sizing)
6. Inlets
The City prefers use of curb opening inlets in most cases. Flow by conditions for
' side curb inlets should attempt to achieve 85% .capture efficiency. Inlets (curb
opening (sag or flowby), grates (sag ; or flowby), combination (sweeper), and
median drop, channels, piping, or hydraulic conduits not found in the Riverside
' County Flood Control Manual shall be designed according to the Federal Highway
Administrations FHWA HEC -22 "Urban Drainage Design Manual ". Use of other
For Catch Basin Sizing Only:
• Rational Method may be. used for projects with less than 10 acres for
catch basin sizing only. The Rational Method may be utilized to
'
determine flow rates generated from each drainage area, to model street
flow capacities and to size catch basins. The Rational Method obtains
flow rates (cfs).
'
For Retention Sizing Only:
• Synthetic Unit Hydrograph Analysis (Shortcut Method) should be used
'
for projects less than 100 acres and the lag time is less than 7 minutes
(see RCFC Hydro Manual page E- 1.2)-. This method results in both flow
rates (cfs) and volumes (cu ft). For smaller projects, either the Rational
'
Method or the Synthetic Unit Hydrograph Analysis (Shortcut Method)
may be used for the hydrology report for the project. The Synthetic Unit
'
Hydrograph Analysis (Shortcut Method) is required for the hydrology
reports for projects less than 100 acres. As stated in the RCFC & WCD
handbook (Plate E -1.2, item 6) "The three hour storm peaks should
normally compare well with rational peaks ".
• Synthetic Unit Hydrograph Analysis should be used with large sites
where' individual water shed areas may exceed 100+ acres. This
'
method results in both flow rates (cfs) and volumes (cu ft).
6. Inlets
The City prefers use of curb opening inlets in most cases. Flow by conditions for
' side curb inlets should attempt to achieve 85% .capture efficiency. Inlets (curb
opening (sag or flowby), grates (sag ; or flowby), combination (sweeper), and
median drop, channels, piping, or hydraulic conduits not found in the Riverside
' County Flood Control Manual shall be designed according to the Federal Highway
Administrations FHWA HEC -22 "Urban Drainage Design Manual ". Use of other
jurisdictional catch basin sizing charts is not allowable. Catch basin sizing charts
can have varied conditional assumptions as compared to HEC -22 analysis.
7. Retention Basin Design
Preliminary basin design shall follow these guidelines. The City of La Quinta
Engineering Bulletin 97 -03 has been superseded by this City of La Quinta
Engineering Bulletin 06 -14. Design criteria include:
• Retention basins shall be sized to contain the design storm and all criteria
listed in this Engineering Bulletin 06 -14. For design purposes, the design
storm shall be the 100 -year storm event that produces the most runoff
reaching the retention basin. Runoff /retention calculations shall be prepared
utilizing Riverside County Flood Control and Water Conservation District
Hydrology Manual guidance to calculate the required retention capacity for
each of the following storm events: 1 hour, 3 hour, 6 hour and 24 hour
storms.
• The maximum allowable water depth of a retention basin when the design
storm is contained is five (5) feet.. Retention basins deeper than 6 -feet are
not allowed, unless the depth of the basin was clearly specified on a
document that was presented to the Planning Commission and /or City
Council during the public hearing when the project received its entitlement.
• Retention basins deeper than 6 feet are not permitted in un -gated
communities. Further more, retention basins deeper than.6 feet shall have
eight (8) feet wide level terraced benches around the entire perimeter of the
basin located at water surface contours where the water is 5, 10 and 15
feet deep, as applicable. In no event shall the maximum water depth exceed
nineteen (19) feet deep in any location when the 100 -year storm is
contained. Retention basins deeper than 6 feet shall also have a five (5) feet
wide level terraced bench located one (1) foot above the 100 -year water
surface level around the entire perimeter of the basin. The retention basin
should be capable of percolating the entire 100 -year storm retention capacity
in less than 72 hours.
• One (1) foot of freeboard shall be provided when the 100 year storm is
contained. The one -foot freeboard requirement is a minimum value.
Freeboard is defined as the elevation differential between the 100 -year water
surface elevation and the nearest street flowline elevation.
• The maximum allowable side slope is 3:1.
• A maintenance access ramp with a maximum 15% slope shall be provided
from the nearest street to the retention basin bottom. Signage indicating
not a pedestrian ramp is required. The ramp shall be located at the nearest
street to the retention basin bottom. The ramp width shall be a minimum of
15 feet.
' '• A nuisance water dissipater shall be installed in the bottom of each retention
basin, pursuant to site specific geotechnical engineering recommendations.
' The nuisance water shall be piped directly to the n.uisance water dissipater
from the storm drain inlet in the street.
' • The retention basin shall be landscaped and properly irrigated.
' • Publicly maintained retention basins shall not be fenced or walled.
• All areas of publicly maintained retention basins shall be visible from the
' adjacent street.
• The percolation rate in a retention basin shall be considered zero unless a site
' specific percolation test is performed and test results are approved by the
City. The maximum allowable percolation rate is two (2) inches per hour.
An emergency overflow route shall be provided for storm volumes greater
than the, design storm. Overflow to a City arterial street is the preferred
routing except in circumstances where significant grade differentials occur
away from the City street network.
8. Retention Basin Nuisance Water Handling
Drywells for nuisance water dissipation are ,utilized in most retention basins
conditional on the site having an acceptably deep water table. Drywells for
retention basins must penetrate a minimum of 10 ft into suitable permeable strata
and must utilize the Maxwell Plus design or equal. The final depth of the drywell
must be above the top of the water table. Shallow drywells for small nuisance
water volumes may utilize the Maxwell IV design or equal. A geotechnical opinion
stating the allowable and specific casing design of the drywell should be provided
to the City for approval.
The use of drywells and sand filters shall be determined by the infiltration testing
(see below). Field experience has shown that areas of homogenous sand deposits
are typically found in north La Quinta. Generally, sand filters can only be used in
areas of homogenous sand deposits, which are typically found in north La Quinta.
Conversely, field experience has shown that historical lake bed areas or equal
lithologies are found in south La Quinta (south of Hwy 111). These historical lake
bed areas would most typically obtain low infiltration rate results. Additionally,
shallow silt lenses may be found throughout the City of La Quinta. Silt lenses or
lake bed areas generally preclude natural percolation as well as the use of sand
filters. Sand filters are, in general, being phased out of La Quinta nuisance water
handling systems. If utilized, sand filter designs shall follow the City of La Quinta
Standard 370. Well site blow off retention must be handled within a separate
nuisance water retention system.
Well site retention shall be capable of handling minimum of 10,000 gallons
9 9
per day. CVWD may allow for installation of a nuisance well site blow off
' retention basin within the well site perimeter if sufficient area and land
dedication is available. All nuisance water shall be retained on site.
' • The filtering system shall be able to contain surges of up to 3 gph /1,000 sq
ft and infiltrate 5 gpd / 1,000 sq ft. The square footage is based on
' landscape area.
• Drywell infiltration rate testing shall be based on the report entitled
' "Riverside 'County Department of Health - Waste Disposal for Homes,
Commercial, and Industry ". This report identifies the drywell test method
which can be used in any location. Drywells may not be installed beyond a
depth that intersects a water table. The final depth of the drywell.must -be
above the top of the water table.
Sand filter infiltration rate testing should use field double ring infiltrometer
ASTM D,3385 -88 (sand lithology) or ASTM D5093 -90 (clay lithology).
Please see the published report and procedure for each ASTM method. City
' acceptance of this testing will be based on boring logs showing homogenous
coarse sand or gravel deposits with a continuous depth of 10ft or more
below the bottom of retention basin. If test shows acceptable percolation,
but the borings show non coarse deposits (silts or. clay), then drywell use is
recommended.
' 9. Retention Basin Percolation for Retention Basin Sizing
• Percolation testing for retention basin sizing calculations should use field
' borings and test with a double ring infiltrometer ASTM D3385 -88 (sand
lithology) or ASTM D5093 -90 (clay lithology) method or U.S. Bureau of
Reclamation . Method for Unsaturated Soils above Groundwater for
verification of percolation.
' .: In cases where double ring infiltrometer testing creates excessive excavation
or safety issues, the U.S. Bureau of Reclamation Method for Unsaturated
Soils above Groundwater should be utilized.
• The ASTM D3385 -88 (sand lithology) or ASTM D5093 -90 (clay lithology)
methods, properly conducted, are preferred over the U.S. Bureau of
' Reclamation Method for Unsaturated Soils above Groundwater testing
method.
•: -The top elevation of the ASTM boring test area should represent the
estimated retention basin bottom. The ASTM D5093 -90 test requires a pre -
soak condition for infiltration testing. The ASTM double ring infiltrometer
' test should terminate approximately 1 foot below the estimated basin
bottom. The infiltration test boring utilized for ,the U.S. Bureau of
Reclamation Method should terminate approximately 3 feet below the
estimated basin bottom with a 3 feet of water head test performed to
simulate percolation.
Percolation test results are subject to City Engineer approval. The total
retention basin percolation rate is based on a combination of City data
review of the following:
• Percolation of 2 inch per hour may be assumed if ASTM D3385-
88 (sand lithology) or ASTM D5093 -90 (clay lithology) test
results confirm GREATER THAN 2" per hour percolation and
confirm no clay or silt layer to a depth of 15 ft below the
bottom of the retention basin.
• If less than 2" per hour percolation is obtained by the ASTM
methods OR U.S. Bureau of Reclamation Method for
Unsaturated Soils above Groundwater, then the finest soil type
found to a depth of 15 ft (continuous sampling) below the
bottom of retention basin will govern the assumed percolation
as follows:
1. Clay /Clayey Soil = 0 in /hr
' 2. Silt Soil = 0 in /hr
3. Coarser Soil than Silt = a demonstrated weighted
average percolation based on multiple borings and ASTM
' D3385 -88 and ASTM D5093-90 tests
■ Landscape cover type at the retention basin according to the
RCFC Hydrology Manual and Soil Conservation Maps may also
further limit percolation.
10. Retaining Walls within Retention Basins
Retaining walls are discouraged for use in retention basins. If specified, walls
should consist of reinforced concrete or equal as approved by the City Engineer to
specifically prevent undermining of the retaining wall footing during and after (quick
drawdown) large storm events. Use of walls as a top ring of the retention basin is
prohibited. Retaining walls will require approval from both the Public Works
Department Director /City Engineer and Community Development Department
Director.
11. Retention Basin Width
Retention basins shall have a minimum width of 20 feet as measured from the
lowest elevation contour. Previously, retention basin widths were governed by City
guidance for aspect ratios for basins depths greater than 6 feet.
12. Overflow Routes
Retention basins should be designed to- overflow to City arterial streets or the
adjacent local street as applicable. Historical flow route should be followed and not
changed on a regional perspective but re- grading and import to achieve an
immediate route to the adjacent street should be considered for projects which
concentrate flows to adjacent open land or off -site developments. Overflow routes
shall be designed using an open channel flow (surface flow). Closed conduit
emergency overflow must be approved by the, City Engineer.
13., Rainfall Intensity
Rainfall intensity for hydrological report preparation is regionally zoned within the
City pursuant to available NOAA data. A regional rainfall intensity map of the City
should be referenced to confirm rainfall amount assumptions provided in the
following table. *'The design storm for the City is 100 -year storm ,(worst case of
24 hour, 6 hour, 3 hour or 1 hour duration). The 500 -year storm is only used to
review for problematic secondary overflows which do not drain to a public arterial
street, creating a trapped water condition.
14. Hydrograph Loss Rates
According to the Riverside County Flood Control Hydrology Manual, the loss rates
generally range from 0.10 to 0.40 in /hr with most falling between 0.20 and 0.25
in /hr. Three and six hour duration storms may use a constant loss rate; however,
the 24 hour duration storm shall obtain a variable loss rate using the equation
found on page E -9 of the manual, which is Ft = C(D -T) "1'55 + Fm. Variable loss
rates are not required for the Synthetic Unit Hydrograph Analysis (Shortcut
Method). Additionally, developed condition' low loss rate calculations on 24 hour
duration storms have been modified pursuant to recent Riverside County Flood
Control guidance.
15. Project Entrance and Emergency Route High Water Maximum Height
During any storm event, a minimum 10 foot wide paved surface at the entrance to
the site or localized sump area which would block emergency vehicular travel shall
never exceed a storm water depth of 1.0 feet at any time. During the major storm
100 yr storm (inches)
Zones
1 h
3hr
6hr
24hr
Zone 1 - Southwest mountains
'2.50
3.40
4.00
6.00
Zone 2 - Southwest mountains
2.30
3.00
3.70
5.00
Zone 3 - West mountains and areas south of
Hwy 111 and west of Washington
2.20
2.80
3.40
4.50
Zone 4 - West of Jefferson and areas east of
Washington including the Cove
2.10
2.70
3.20
4.25
Zone 5 - East of Jefferson and west of a
staggered line trending south west of Calhoun
Street and Avenue 50
2.00
2.60
3.10
4.00
Zone 6 - West of a staggered line trending south
west of Calhoun Street and Avenue 50
1.90
2.50
3.00
3.75
14. Hydrograph Loss Rates
According to the Riverside County Flood Control Hydrology Manual, the loss rates
generally range from 0.10 to 0.40 in /hr with most falling between 0.20 and 0.25
in /hr. Three and six hour duration storms may use a constant loss rate; however,
the 24 hour duration storm shall obtain a variable loss rate using the equation
found on page E -9 of the manual, which is Ft = C(D -T) "1'55 + Fm. Variable loss
rates are not required for the Synthetic Unit Hydrograph Analysis (Shortcut
Method). Additionally, developed condition' low loss rate calculations on 24 hour
duration storms have been modified pursuant to recent Riverside County Flood
Control guidance.
15. Project Entrance and Emergency Route High Water Maximum Height
During any storm event, a minimum 10 foot wide paved surface at the entrance to
the site or localized sump area which would block emergency vehicular travel shall
never exceed a storm water depth of 1.0 feet at any time. During the major storm
event, the proposed drainage will not block or unreasonably increase or concentrate
within the meaning of California Drainage Law, drainage runoff from or to any of
the adjoining properties.
16. 10 Year Storm & Public Streets - Catch Basin Spacing
For a design frequency storm of 10 years, the design maximum allowable arterial
spreads will equal 1 lane (10 - 12 feet) + bike lane (if present 4 - 8 feet). The
loss of only 1 lane of use is desired for 10 year storms. Catch basin spacing
generally is required between 1200 - 2000 feet on City arterial roadways. The
engineer may provide calculations showing that the spacing may increase. The
engineer must also demonstrate that the flow in the street will not topple over
curbs or R/W during changes in direction of the open channel conduit (typically the
street). Inlets will be required at locations on arterial streets prior to the flow
crossing at intersections and major driveways or entrances. Typically (verify with
the Conditions of Approval), inlets must be located to intercept at least 85% of the
total project projected storm flow. This also includes tributary areas found in the
public right of way.
17. 100 Year Storm and Public Streets
For a design frequency storm of 100 years, the design maximum allowable spreads
are to the respective City right of way.
18. Report Outline - The following shall be found within all hydrology reports:
• Signed and stamped by a California Registered Civil Engineer
• Table of Contents
•. Vicinity Map with Site Location
•: Project description with historical. flow pattern exceeding a site
circumference of 1 mile, unless limited by clearly defined watershed
boundaries
• Analysis method used (Rational-or Synthetic Unit Hydrograph)
• Hydrology map showing all sub areas with coefficients.
• Rational Method showing tabling in a node -by -node sequence per Riverside
County Flood Control Manual or equal.
• Soils map used to determine soil losses
Catch Basin Sizing
Retention Basin requirements with percolation as determined by field testing
and City policies. Please also provide retention basin volumetric calculations
assuming zero percolation for sensitivity analysis.
:. Volume calculations w /Cross Sections of the. Retention Basin.
19. Retention Basin Freeboard Requirements
A minimum of 1 foot of freeboard between the retention basin major storm
elevation (HGL,00 ) and the flow line of the nearest street (typically the inlet) is
required.' The 1 foot ¢ minimum freeboard specification may be modified to a
reduced freeboard height which achieves 25% of the 100 year storm capacity in
large area, shallow retention basin ' configurations. Historical City maximum
freeboard specifications are now'eliminated.
' 20. Hydraulic Grade Line (HGL) Starting Points
Projects within the City of La Quinta that are required to contain their 100 year
storm flows shall show two (2) separate HGLs for maximum flow rate (HGL,o) and
maximum volume (HGL,00)•
The first HGL (HGL,o) will reflect the values from the 10 year frequency design
storm.::. Values. of Q,o and V,o will be determined from the Rational Method. Conduit
sizing shall be based on non pressure type flow (HGL shall not be located above the
crown of a pipe).
The second HGL (HGL,00) will reflect values based on the maximum 100 year
frequency design storm. The HGL,00 shall show that the maximum 100 year storm
can be retained within the project and the use of the project's infrastructure shall
be maintained.
21. 10 Year Frequency Design Storm HGL Calculation
This HGL shall start at or above an elevation in the downstream retention basin
that is equal to the '/2 depth of the retention elevation caused by the 100 year
frequency design storm event. The piping system shall be designed based on open
channel flow as opposed to pressure flow. This HGL should indicate the hydraulic
conditions at the maximum storm water flow rate. Requirements:
• Pressure pipe flow not allowed
• Identify this HGL as the HGL,o on the hydraulic calculations and storm drain
plan profile
• Velocity not less than 2.5 fps
:. Pipe sized based on Rational Method
Head losses shall be 'based on HEC 22 Ch 7.
• HGL freeboards: 6" or greater below CB flow line
22. 100 Year Frequency Design Storm HGL Calculation
This HGL shall start at a location at the top of the retention basin water level
caused by the 100 year design storm determined using the Synthetic Unit
Hydrograph. This HGL should indicate the hydraulic conditions at the maximum
storm water volume with a full basin or channel. Requirements:
• Velocity (no requirement)
• Identify this HGL as the HGL,00 on the hydraulic calculations and storm drain
plan profile
• Pressure pipe flow allowed.
• Pipe size based on Rational Method.
• No part of the emergency route shall obtain a water depth greater than
1.5 feet.
• HGL Freeboards and Elevations
• Difference in elevation between CB flow line and HGL in retention basin
shall be between 0 and 12 inches.
• 1 ft min from top of manhole cover
• Not to exceed 7ft above the top of pipe
• HGL must be located 1 ft below the adjacent Pad Elevation
23. Whitewater Channel HGL
Assuming major storm coincidental occurrences are taken into consideration'
already (see page 7 -8 of HEC -22 Storm Drains), the projects HGL100 shall be
located 2 feet below Whitewater Channel's estimated HGL500 (this is also equal to
1 foot below the existing Whitewater Concrete Channel Lining). Time of
concentration for channel discharge will assume a full channel. Flap gate
installation may be applicable, based on project elevations.
24. La Quinta Evacuation Channel HGL
The Evacuation Channel obtains an HGL,00 with an approximate elevation of 48.0
pursuant to information provided by CVWD to the City. Additional elevation
information for the Evacuation Channel is currently under review at CVWD. The
elevation is based on NGVD 1929. 'Elevations showing on the plan should be based
on the same. Flap gate installation may be applicable based on project elevations.
n
25: Retention Basin Landscape Requirements
Retention basins shall be landscaped and properly irrigated. The retention basin
landscape plans must be approved by the City Engineer /Public Works Director. The
retention basin must be capable of draining the 100 year storm within 72 hours.
Project incapable of draining the 100 year storm within 72 hours will be reviewed
by the City for enhancement options to promote drainage conveyance. In basins
with depths exceeding 8ft, trees shall be planted in the 8 -foot wide terraces. The
number of trees shall be calculated by multiplying the basin lot boundary length by
the number of 8 -foot wide terraces in the basin and then dividing by 100.
26. Typical Storm Drain Pipe Gradients & Velocity
' Primary street storm drains, designers should assume minimum grade = 0.3%-
based on minimum flow velocity of 2.5 ft /sec. For local area drains, 4 " -6" pipe
minimum grade = 1 %, larger pipe diameters = 0.5% should be assumed.
' 27. Typical Street Flows
' Street flows shall meet the design requirements of FHWA HEC -22. When gutters
obtain small slopes, or where sediment may accumulate, or when parking is
allowed on the side of the street, the designer should increase the n value by 0.02.,
1 28. Storm Drain Easement Width Requirements
' The City of La Quinta requirements for minimum widths (generally 20 feet,
excepting deep drainage systems) of storm drain easements is found in easement
requirement charts from the Riverside County Transportation Department. Ten (10)
foot easements using Reinforced Concrete Pipe (RCP) in side yards may be used at
the discretion of the City Engineer.
' 29. Surface Usage within the Retention Basin
The developer may 'use the retention basin surface for recreational activities
' (tennis, volley ball, park, etc) or other permitted usages approved by the
Community Development Director provided the retention basin's intended
engineering use is met and that typical ADA improvements are provided. All
' improvements found within the retention basin shall be removed if they inhibit the
maintenance or function of the retention basin.
m m m m m m m m m m m m m m m m m m m
(GOLF COURSE) NODE MAP
PARCEL 2 GRAPHIC SCALE
PARCEL MAP 32 o 9
20' CVWD ''� o so 100 200
.,:_-UTILITY - UTILITY E
IN FM )
L07 33 inch = 100 &
.,� TRACT 28611 I
0, UE mph
I
TRACT 267400 =1
LOT 91
to 10 10
m m no ♦ �O�
(GOLF COURSE) I �� ,•
•
(LOOT 35 � AREA "B -1» � •
TRACT 20611 �PE =54. A =1.14 AC •
I �0 �1RC ELF I •
' 'F'ARCE P 32691
g1
C6 1 •
100 =2.71 CFS MAX •
NO E 11
i 10 =8.79 CFS MAX to to �. ♦,
to
wo
1 CB #2
` O ,0100 =6.08 CFS MAX
-off PE =60.0 �♦
�?\ TRACT 287,40-
77400 e � ��'� �♦
LO1 277 �o
/ AREA »B -2"
A =2.84 AC
NO BUILD ESMT �
LOT 36
TRACT 26740 740 tl Sao • to ow ♦ �
: i i . `....� M
'•b00� �o
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
2 AREA DESIGNATION
"13-1"
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
[51 AREA ACRES
1.1400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
[81L-MILES ([61-[71)
0.063
9 LCA - INCHES
-
10 LCA - MILES ( [71-[91
0.009
[111 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
161.00
14 S - FEET /MILE ([13/[81)
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([8]-[101/[15])
0.0000111
17 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24-[17]-[16]'-0.38)
(PLATE E -3
0.0088816
[191 LAG TIME - MINUTES (60-[18])
0.53
20 25% OF LAG TIME (0.25-[191)
0.13
21 40% OF LAG TIME 0.40-[19]
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAINFALL DATA
[1 ]SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
11 00YR 24HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
L51
F [5]
[7]
AVG.
POINT
RAIN IN,
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
U
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
[13]
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
7 5= - F 7= 2.80
F 9= -
7 11 =
3.40
F 13= - E 15= 4.50
E161 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1
1
[17] ADJ.AVG.POINT RAIN 2.8
([16]* [7],ETC)
3.4
4.5
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[61 LAG TIME - MINUTES
0.53
[7] UNIT TIME -PERCENT OF LAG (100- [5v[61)
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
4.5
1[111 VARIABLE LOSS RATE (AVG) - IN /HR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0.036
[13 CONSTANT LOSS RATE - IN /HR
0
[14] LOW LOSS RATE - PERCENT
I
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] "[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4' 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21 ]
STORM
RAIN
IN /HR
60[101[201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
100[5]
MAX
LOW
1
0.20
0.036
0.000
0.000
0.036
0.04
2
0.30
0.054
0.000
0.000
0.054
0.06
3
0.30
0.054
0.000
0.000
0.054
0.06
4
0.40
0.072
0.000
0.000
0.072
0.08
5
0.30
0.054
0.0001
0.000
0.054
0.06
6
0.30
0.054
0.000
0.000
0.054
0.06
7
0.30
0.054
0.000
0.000
0.054
0.06
8
0.40
0.072
0.000
0.000
0.072
0.08
9
0.40
0.072
0.000
0.000
0.072
0.08
10
0.40
0.072
0.000
0.000
0.072
0.08
11
0.50
0.090
0.0001
0.000
0.090
0.10
12
0.50
0.090
0.000
0.000
0.090
0.10
13
0.50
0.090
0.000
0.000
0.090
0.10
14
0.50
0.090
0.000
0.000
0.090
0.10
15
0.50
0.090
0.000
0.000
0.090
0.10
16
0.60
0.108
0.000
0.000
0.108
0.12
17
0.60
0.108
0.000
0.000
0.108
0.12
18
0.70
0.126
0.000
0.000
0.126
0.14
19
0.70
0.126
0.000
0.000
0.126
0.14
20
0.80
0.144
0.000
0.000
0.144
0.16
21
0.60
0.108
0.000
0.000
0.108
0.12
22
0.70
0.126
0.000
0.000
0.126
0.14
23
0.80
0.144
0.000
0.000
0.144
0.16
24
0.80
0.144
0.000
0.000
0.144
0.16
25
0.90
0.162
0.000
0.000
0.162
0.18
26
0.90
0.162
0.000
0.000
0.162
0.18
27
1.00
0.180
0.000
0.000
0.180
0.21
28
1.00
0.180
0.000
0.000
0.180
0.21
29
1.00
0.180
0.000
0.000
0.180
0.21
30
1.10
0.198
0.000
0.000
0.198
0.23
31
1.2
0.216
0.000
0.000
0.216
0.25
32
1.30
0.234
0.000
0.000
0.234
0.27
33
1.50
0.270
0.000
0.000
070
0.31
34
1.50
0.270
0.000
0.000
0.270
0.31
35
1.60
0.288
0.000
0.000
0.2881
0.33
36
1.70
0.306
0.000
0.000
0.3061
0.35
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.53
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
4.5
(11] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0.39
[13] CONSTANT LOSS RATE - INCHES PER HO
0
[14] LOW LOSS RATE - PERCENT
doo
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60f101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
1
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
37
1.90
0.342
0.000-
0.342
0.39
38
2.00
0.360
0.000-
0.360
0.41
39
2.10
0.378
0.000-
0.378
0.43
40
2.20
0.396
0.000-
0.396
0.45
41
1.50
0.270
0.000
0.000
0.270
0.31
42
1.50
0.270
0.000
0.000
0.270
0.31
43
2.00
0.360
0.000-
0.360
0.41
44
2.00
0.360
0.000
-
0.360
0.41
45
1.90
0.342
0.000
0.000
0.342
0.39
46
1.90
0.342
0.0001
0.000
0.342
0.39
47
1.70
0.306
0.000
0.000
0.306
0.35
48
1.80
0.324
0.000
0.000
0.324
0.37
49
2.50
0.450
0.000-
0.450
0.51
50
2.60
0.468
0.000-
0.468
0.53
51
2.80
0.504
0.000-
0.504
0.57
52
2.90
0.522
0.0001-
0.522
0.60
53
3.40
0.612
0.000-
0.612
0.70
54
3.40
0.612
0.000-
0.612
0.70
55
2.30
0.414
0.006-
0.414
0.47
56
2.30
0.414
0.000
-
0.414
0.47
57
2.70
0.486
0.000
-
0.486
0.55
58
2.60
0.468
0.000
-
0.468
0.53
59
2.60
0.468
0.000-
0.468
0.53
60
2.50
0.450
0.000
-
0.450
0.51
61
2.40
0.432
0.000-
0.432
0.49
62
2.30
0.414
0.000-
0.414
0.47
63
1.90
0.342
0.000
0.000
0.342
0.39
64
1.90
0.342
0.000
0.000
0.342
0.39
65
0.40
0.072
0.000
0.000
0.072
0.08
66
0.40
0.072
0.000
0.000
0.072
0.08
67
0.30
0.054
0.000
0.000
0.054
0.06
68
0.30
0.054
0.000
0.000
0.054
0.06
69
0.50
0.090
0.000
0.000
0.090
0.10
70
0.50
0.090
0.000
0.000
0.090
0.10
71
0.50
0.0901
0.000
0.000
0.090
0.10
72
1 0.40
0.0721
0.0001
0.000
0.0721
0.08
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA -ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
073
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[1 1] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[1 3] CONSTANT LOSS RATE - INCHES PER HO
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[4 11181 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60f101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
73
0.40
0.072
0.000
0.000
0.072
0.08
74
0.40
0.072
0.000
0.000
0.072
0.08
75
0.30
0.054
0.000
0.000
0.054
0.06
76
0.20
0.036
0.000
0.000
0.036
0.04
77
0.30
0.054
0.000
0.000
0.054
0.06
78
0.40
0.072
0.000
0.000
0.072.
0.08
79
0.30
0.054
0.000
0.000
0.054
0.06
80
0.20
0.036
0.000
0.000
0.036
0.04
81
0.30
0.054
0.000
0.000
0.054
0.06
82
0.30
0.054
0.0001
0.000
0.054
0.06
83
0.30
0.054
0.000
0.000
0.0541
0.06
84
0.20
0.036
0.000
0.000
0.036
0.04
85
0.30
0.054
0.000
0.000
0.054
0.06
86
0.20
0.036
0.000
0.000
0.036
0.04
87
0.30
0.054
0.000
0.000
0.054
0.06
88
0.20
0.036
0.0001
0.000
0.036
0.04
89
0.30
0.054
0.0001
0.000
0.054
0.06
90
0.20
0.036
0.000
0.000
0.036
0.04
91
0.20
0.036
0.000
0.000
0.036
0.04
92
0.20
0.036
0.000
0.000
0.036
0.04
93
0.20
0.036
0.000
0.000
0.036
0.04
94
0.20
0.036
0.000
0.000
0.036
0.04
95
0.20
0.036
0.000
0.000
0.036
0.04
96
0.20
0.036
0.000
0.000
0.036
0.04
1=100%
Z=
18.000
8404CF
A/G STORAGE
OCF
U/G STORAGE
18.00 IN /HR *0.25= 4.50 "
4.50 " * 0.083 * 1.1400 ACRES=
0.4258 AC FT= 18547 CF
OCF
PERC LOSS IN 24 HRS
8404CF
PROVIDED
RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32981
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
2 AREA DESIGNATION
"B -1"
[31 AREA - SQ INCHES
-
4 AREA ADJUSTMENT FACTOR
-
[51 AREA ACRES
1.1400
6 L- INCHES
-
[711--ADJUSTMENT FACTOR
-
[811--MILES ([61-[71)
0.063
[91 LCA - INCHES
-
10 LCA - MILES ( [71'[91
0.009
[111 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
161.00
14 S - FEET /MILE ([13/[81)
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([8]-[101/[151)
0.00001122
17 AVERAGE MANNING "N"
0.015
[181 LAG TIME - HOURS (24'1171-[16]'-0.38)
(PLATE E -3
0.009
19 LAG TIME - MINUTES (60'[18])
0.54
[20125% OF LAG TIME (0.25-[191)
0.13
[21140% OF LAG TIME (0.40-[19])
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAINFALL DATA
1 SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
1100YR 3HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
L5]
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
m
7- [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
[13]
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= - E 7= 2.80
7 9= -
7- 11 =
3.40
F 13= - 7 15= 4.50
E161 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1
1
[17] ADJ.AVG.POINT RAIN 2.8
([161* F [71,ETC)
3.4
4.5
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32981
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
10
[6] LAG TIME - MINUTES
0.54
[7] UNIT TIME - PERCENT OF LAG (100 *[5] /[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 3HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
2.8
1[111 VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0.437
131 CONSTANT LOSS RATE - INCHES PER HOUR
0
[1 4] LOW LOSS RATE - PERCENT
mo
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4.18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
100[5]
MAX
LOW
1
2.60
0.437
0.00
0.437
0.50
2
2.60
0.437
0.00
0.437
0.50
3
3.30
0.554
0.00
0.554
0.63
4
3.30
0.554
0.00
0.554
0.63
5
3.30
0.554
0.00
0.554
0.63
6
3.40
0.571
0.00
0.571
0.65
7
4.40
0.739
0.00
0.739
0.84
8
4.20
0.706
0.00
0.706
0.80
9
5.30
0.890
0.00
0.890
1.02
10
5.10
0.857
0.00
0.857
0.98
11
6.40
1.075
0.00
1.075
1.23
12
5.90
0.991
0.00
0.991
1.13
13
7.30
1.226
0.00
1.226
1.40
14
8.50
1.428
0.00
1.428
1.63
15
14.10
2.369
0.00
2.369
2.70
16
14.10
2.369
0.00
2.369
2.70
17
3.80
0.638
0.00
0.638
0.73
18
2.40
0.403
0.00
0.403
0.46
1 =100%
F= 16.80
8404 CF
A/G STORAGE
0 CF
U/G STORAGE 16.80 IN /HR *0.17= 2.80 "
PERC LOSS IN 3 HRS 2.80 " * 0.083 * 1.1400 ACRES=
PROVIDED 0.2649 AC FT= 11540.61 CF
0 CF
8404 CF
PROJECT: PM 32981
BY: AMG 100 YR / 3 HR
DATE: 5/27/08
JGB #: 06002
2.500 RAINFALL INTENSITY (IN /HR)
2.000
1.500
1.000
0.500
0.000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
0100 / 3HR
3.00
2.50
2.00
1.50
1.00
0.50
0.00
=LE =Ld-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
' RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"13-1"
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
[51 AREA -ACRES
1.1400
6 L- INCHES
-
[711--ADJUSTMENT FACTOR
-
8 L -MILES ([61-[71)
0.063
9 LCA - INCHES
-
10 LCA - MILES ([71-[91)
0.009
11 ELEVATION OF HEADWATER
210.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
161.00
14 S - FEET /MILE ([13/[81)
2555.56
15 S * *0.5
50.55
16 L *LCA/S * *.5 ([81-[101/[15])
0.00001122
17 AVERAGE MANNING "N"
0.015
[181 LAG TIME - HOURS 24* 171'[16]-'0.38)
(PLATE E -3
0.00891937
[191 LAG TIME - MINUTES (60-[18])
0.54
20 25% OF LAG TIME (0.25'[19])
0.13
[21140% OF LAG TIME (0.40-[19])
0.21
[22] UNIT TIME - MINUTES (25 -[21])
24.79
RAINFALL DATA
[1 ]SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
1100YR 6HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
L5]
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
n
7-191
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13] [14]
AREA [131
SQ F [13]
INCHES
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
7 5= 15.45 F 7= 2.18([16]
F 9= 19.7 7-[Ill=
3.40
F 13= 19.7 E 15= 4.50
16 AREAL ADJ FACTOR 1
SEE PLATE E -5.8
1
1
[1 7] ADJ.AVG. POI NT RAIN 2.*
F [7], ETC)
3.4
4.5
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -1"
[3] DRAINAGE AREA - ACRES
1.1400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[3]
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.54
[7] UNIT TIME - PERCENT OF LAG (100 *(5] /[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 6HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
3.4
1[111 VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13 CONSTANT LOSS RATE - INCHES PER HOUR
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF.LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21 ]
STORM
RAIN
IN /HR
6010 20
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
MAX
LOW
1
1.70
0.231
0.00
0.00
0.23
0.3
2
1.90
0.258
0.00
0.00
0.26
0.3
3
2.10
0.286
0.00
0.00
0.29
0.3
4
2.20
0.299
0.00
0.00
0.30
0.3
5
2.40
0.326
0.00
0.00
0.33
0.4
6
2.40
0.326
0.00
0.00
0.33
0.4
7
2.40
0.326
0.00
0.00
0.33
0.4
8
2.50
0.340
0.00
0.00
0.34
0.4
9
2.60
0.354
0.00
0.00
0.35
0.4
10
2.70
0.367
0.00
0.00
0.37
0.4
11
2.80
0.381
0.00
0.00
0.38
0.4
12
3.00
0.408
0.00
0.00
0.41
0.5
13
3.20
0.435
0.00
0.00
0.44
0.5
14
3.60
0.490
0.00
0.00
0.49
0.6
15
4.30
0.585
0.00
0.00
0.58
0.7
16
4.70
0.639
0.00
0.00
0.64
0.7
17
5.40
0.734
0.00
0.00
0.73
0.8
18
6.20
0.843
0.00
0.00
0.84
1.0
19
6.90
1.020
0.00
0.00
1.02
1.2
20
7.50
1.442
0.00
0.00
1.44
1.6
21
10.60
1.972
0.00
0.001
1.97
2.2
22
14.50
0.462
0.00
0.001
0.46
0.5
23
3.40
0.136
0.00
0.00
0.14
0.2
24
1.00
0.136
0.00
0.00
0.14
0.2
8404 CF
A/G STORAGE
0 CF
U/G STORAGE
0 CF
PERC LOSS IN 6 HRS
8404 CF
PROVIDED
1 =100%
F= 7.63
7.63 IN /HR *0.25= 1.9074 "
1.9074 " * 0.083 * 1.1400 ACRES=
0.1805 AC FT= 7861.63 CF
PROJECT: ?M 32391
BY:.AMG
DATE: 5/27/08 100 YR / 6 HR
JOB* 06002
RAINFALL INTENSITY (IN /HR)
2.50
2.00
1.50
1.00
0.50
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Q100 / 6HR
2.5
2.0
1.5
'
1.0
0.5
0.0
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 3HR 11540.61 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
2.6
300.06
0.00
0.00
2
2.6
300.06
0.00
0.00
3
3.3
380.84
0.00
0.00
4
3.3
380.84
0.00
0.00
5
3.3
380.84
0.00
0.00
6
3.4
392.38
0.00
0.00
7
4.4
507.79
0.00
0.00
8
4.2
484.71
0.00
0.00
9
5.3
611.65
0.00
0.00
10
5.1
588.57
0.00
0.00
11
6.4
738.60
0.00
0.00
12
5.9
680.90
0.00
0.00
13
7.3
842.46
0.00
0.00
14
8.5
980.95
0.00
0.00
15
14.1
1627.23
793.87
1.32
16
14.1
1627.23
1627.23
2.71
17
3.8
438.54
438.54
0.73
18
2.4
276.97
276.97
0.46
F=
11540.61
0
SHT 1 OF 5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 6HR
7861.63 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Qloo
1
1.7
133.65
0.00
0.00
2
1.9
149.37
0.00
0.00
3
2.1
165.09
0.00
0.00
4
2.2
172.96
0.00
0.00
5
2.4
188.68
0.00
0.00
6
2.4
188.68
0.00
0.00
7
2.4
188.68
0.00
0.00
8
2.5
196.54
0.00
0.00
9
.2.6
204.40
0.00
0.00
10
2.7
212.26
0.00
0.00
11
2.8
220.13
0.00
0.00
12
3.0
235.85
0.00
0.00
13
3.2
251.57
0.00
0.00
14
3.6
283.02
0.00
0.00
15
4.3
338.05
0.00
.0.00
16
4.7
369.50
0.00
0.00
17
5.4
424.53
0.00
0.00
18
6.2
487.42
0.00
0.00
19
6.9
542.45
0.00
0.00
20
7.5
589.62
0.00
0.00
21
10.6
833.33
0.00
0.00
22
14.5
1139.94
0.00
0.00
23
3.4
267.30
0.00
0.00
24
1.0
78.62
0.00
0.00
F=
7861.63
SHT 2 OF 5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
0.20
37.09
0.00
0.00
2
0.30
55.64
0.00
0.00
3
0.30
55.64
.0.00
0.00
4
0.40
74.19
0.00
0.00
5
0.30
55.64
0.00
0.00
6
0.30
55.64
0.00
0.00
7
0.30
55.64
0.00
0.00
8
0.40
74.19
0.00
0.00
9
0.40
74.19
0.00
0.00
10
0.40
74.19
0.00
0.00
11
0.50
92.74
0.00
0.00
12
0.50
92.74
0.00
0.00
13
0.50
92.74
0.00
0.00
14
0.50
92.74
0.00
0.00
15
0.50
92.74
0.00
0.00
16
0.60
111.28
0.00
0.00
17
0.60
111.28
0.00
0.00
18
0.70
129.83
0.00
0.00
19
0.70
129.83
0.00
'0.00
20
0.80
148.38
0.00
0.00
21
0.60
111.28
0.00
0.00
22
0.70
129.83
0.00
0.00
23
0.80
148.38
0.00
0.00
24
0.80
148.38
0.00
0.00
25
0.90
166.92
0.00
0.00
26
0.90
166.92
0.00
0.00
27
1.00
185.47
0.00
0.00
28
1.00
185.47
0.00
0.00
29
1.00
185.47
0.00
0.00
30
1.10
204.02
0.00
0.00
31
1.20
222.56
0.00
0.00
32
1.30
241.11
0.00
0.00
33
1.50
278.21
0.00
0.00
34
1.50
278.21
0.00
0.00
35
1.60
296.75
0.00
0.00
36
1.70
315.30
0.00
0.00
37
1.90
352.39
0.00
0.00
38
2.00
370.94
0.00
0.00
39
2.10
389.49
0.00
0.00
40
2.20
408.03
0.00
0.00
41
1.50
278.21
0.00
0.00
42
1.50
278.21
0.00
0.00
43
2.00
370.94
0.00
0.00
44
°2.00
370.94
0.00
0.00
45
1.90
352.39
0.00
0.00
46
1.90
352.39
90.53
0.10
SHT3OF5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
47
1.70
315.30
315.30
0.35
48
1.80
333.85
333.85
0.37
49
2.50
463.68
463.68
0.52
50
2.60
482.22
482.22
0.54
51
2.80
519.32
519.32
0.58
52
2.90
537.86
537.86
0.60
53
3.40
630.60
630.60
0.70
54
3.40
630.60
630.60
0.70
55
2.30
426.58
426.58
0.47
56
2.30
426.58
426.58
0.47
57
2.70
500.77
500.77
0.56
58
2.60
482.22
482.22
0.54
59
2.60
482.22
482.22
0.54
60
2.50
463.68
463.68
0.52
61
2.40
445.13
445.13
0.49
62
2.30
426.58
426.58
0.47
63
1.90
352.39
352.39
0.39
64
1.90
352.39
352.39
0.39
65
0.40
74.19
74.19
0.08
66
0.40
74.19
74.19
0.08
67
0.30
55.64
55.64
0.06
68
0.30
55.64
55.64
0.06
69
0.50
92.74
92.74
0.10
70
0.50
92.74
92.74
0.10
71
0.50
•92.74
92.74
0.10
72
0.40
74.19
74.19
0.08
73
0.40
74.19
74.19
0.08
74
0.40
74.19
74.19
0.08
75
0.30
55.64
55.64
0.06
76
0.20
37.09
37.09
0.04
77
0.30
55.64
55.64
0.06
78
0.40
74.19
74.19
0.08
79
0.30
55.64
55.64
0.06
80
0.20
37.09
37.09
0.04
81
0.30
55.64
55.64
0.06
82
0.30
55.64
55.64
0.06
83
0.30
55.64
55.64
0.06
84
0.20
37.09
37.09
0.04
85
0.30
55.64
55.64
0.06
86
0.20
37.09
37.09
0.04
87
0.30
55.64
55.64
0.06
88
0.20
37.09
37.09
0.04
89
0.30
55.64
55.64
0.06
90
0.20
37.09
37.09
0.04
91
0.20
37.09
37.09
0.04
92
0.201
37.09
1 37.09
0.04
0
SHT 4 OF 5
DISCHARGE ANALYSES OF PARCEL 1 PM 32891
BY: AMG
DATE: 5 /27/08
JOB #: 06008 AVAILABLE STORAGE= 8404.00 CF
100 YR 24HR
18547.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
93
0.20
37.09
37.09
0.04
94
0.20
37.09
37.09
0.04
95
0.20
37.09
37.09
0.04
96
0.20
37.09
37.09
0.04
F=
18547.00
0
SHT5OF5
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: LOT 27 TR28470 -1
BASIC DATA CALCULATION FORM BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
[31 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
5 AREA ACRES
2.8400
6 L- INCHES
[711--ADJUSTMENT FACTOR
-
[811--MILES ([61'[71)
0.122
9 LCA - INCHES
-
10LCA -MILES 7 *9
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
l 31 H- FEET 11 - 12
311.00
14 S - FEET /MILE ([13/[81)
2549.18
15 S * *0.5
50.49
16 L *LCA/S * *.5 ([81'[10]/[151)
0.0000375
[171 AVERAGE MANNING "N"
0.015
[181 LAG TIME - HOURS (24-[17]'[16]'-0.38)
(PLATE E -3
0.0141033
[191 LAG TIME - MINUTES (60-[18])
0.85
[20125% OF LAG TIME (0.25-[19])
0.21
[21140% OF LAG TIME (0.40-[19])
0.34
[22] UNIT TIME - MINUTES (25 -[21])
24.66
RAINFALL DATA
1 SOURCE
IRCFCWCD
2 FREQUENCY - YEARS
I 100YR 24HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
[5j
E [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
IM
F [9]
[11 ]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
[13]
E [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
k(SEE
7- 5= - 7 7= 2.80
- F
11 =
3.40
F 13= - F 15= 4.50
16 AREAL ADJ FACTOR 1
LATE E -5.8
1
1
[17] ADJ.AVG.POINT RAIN 2.8
[7],ETC)
3.4
4.5
' RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: LOT 27 TR28470 -1
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645'[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
1[111 VARIABLE LOSS RATE (AVG) - IN /HR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
13 CONSTANT LOSS RATE - IN /HR
0
[14] LOW LOSS RATE - PERCENT
0
[INNItM:K- T.rz.Ta YIJ:
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
6010 20
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
1
0.20
0.036
0.0001
0.000
0.036
0.10
2
0.30
0.054
0.0001
0.000
0.054
0.15
3
0.30
0.054
0.0001
0.000
0.054
0.15
4
0.40
0.072
0.000
0.000
0.072
0.20
5
0.30
0.054
0.000
0.000
0.054
0.15
6
0.30
0.054
0.000
0.000
0.054
0.15
7
0.30
0.054
0.000
0.000
0.054
0.15
8
0.40
0.072
0.000
0.000
0.072
0.20
9
0.40
0.072
0.000
0.000
0.072
0.20
10
0.40
0.072
0.000
0.000
0.072
0.20
11
0.50
0.090
0.000
0.000
0.090
0.26
12
0.50
0.090
0.0001
0.000
0.090
0.26
13
0.50
0.090
0.000
0.000
0.090
0.26
14
0.50
0.090
0.000
0.000
0.090
0.26
15
0.50
0.090
0.000
0.000
0.090
0.26
16
0.60
0.108
0.000
0.000
0.108
0.31
17
0.60
0.108
0.0001
0.000
0.108
0.31
18
0.70
0.126
0.0001
0.000
0.126
0.36
19
0.70
0.126
0.000
0.000
0.126
0.36
20
0.80
0.144
0.000
0.000
0.144
0.41
21
0.60
0.108
0.000
0.000
0.108
0.31
22
0.70
0.126
0.000
0.000
0.126
0.36
23
0.80
0.144
0.000
0.000
0.144
0.41
24
0.80
0.144
0.000
0.000
0.144
0.41
25
0.90
0.162
0.000
0.000
0.162
0.46
26
0.90
0.162
0.000
0.000
0.162
0.46
27
1.00
0.180
0.000
0.000
0.180
0.51
28
1.00
0.180
0.000
0.000
0.180
0.51
29
1.00
0.180
0.000
0.000
0.180
0.51
30
1.10
0.198
0.000
0.000
0.198
0.56
31
1.2
0.216
0.000
0.000
0.216
0.61
32
1.30
0.234
0.000
0.000
0.234
0.66
33
1
1.50
0.270
0.000
0.000
0.270
0.77
34
1.50
0.270
0.000
0.000
0.270
0.77
35
1.60
0.288
0.000
0.000
0.288
0.82
36
1.70
0.306
0.0001
0.000
0.306
0.87
RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28470 -1
BY: AMG
DATE: 5/27/08
JOB ##: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
(3) DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645`[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME -PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[l 11 VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12) MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE- INCHES PER HO
01['141
LOW LOSS RATE - PERCENT
I 0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7]'[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[411181
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60f101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LO W
37
1.90
0.342
0.000
0.000
0.342
0.97
38
2.00
0.360
0.000
0.000
0.360
1.02
39
2.10
0.378
0.000
0.000
0.378
1.07
40
2.20
0.396
0.000
0.000
0.396
1.12
41
1.50
0.270
0.000
0.000
0.270
0.77
42
1.50
0.270
0.000
0.000
0.270
0.77
43
2.00
0.360
0.000
0.000
0.360
1.02
44
2.00
0.360
0.000
0.000
0.360
1.02
45
1.90
0.342
0.000
0.000
0.342
0.97
46
1.90
0.342
0.0001
0.000
0.342
0.97
47
1.70
0.306
0.0001
0.000
0.306
0.87
48
1.80
0.324
0.0001
0.000
0.324
0.92
49
2.50
0.450
0.0001
0.000
0.450
1.28
50
2.60
0.468
0.000
0.000
0.468
1.33
51
2.80
0.504
0.000
0.000
0.504
1.43
52
2.90
0.522
0.000
0.000
0.522
1.48
53
3.40
0.612
0.000
0.000
0.612
1.74
54
3.40
0.612
0.000
0.000
0.612
1.74
55
2.30
0.414
0.000
0.000
0.414
1.18
56
2.30
0.414
0.000
0.000
0.414
1.18
57
2.70
0.486
0.000
0.000
0.486
1.38
58
2.60
0.468
0.000
0.000
0.468
1.33
59
2.60
0.468
0.000
0.000
0.468
1.33
60
2.50
0.450
0.000
0.000
0.450
1.28
61
2.40
0.432
0.000
0.000
0.432
1.23
62
2.30
0.414
0.000
0.000
0.414
1.18
63
1.90
0.342
0.000
0.000
0.342
0.97
64
1.90
0.342
0.000
0.000
0.342
0.97
65
0.40
0.072
0.000
0.000
0.072
0.20
66
0.40
0.072
0.000
0.000
0.072
'0.20
67
0.30
0.054
0.000
0.000
0.054
0.15
68
0.30
0.054
0.000
0.000
0.054
0.15
69
0.50
0.090
0.000
0.000
0.090
0.26
70
0.50
0.090
0.000
0.000
0.090
0.26
71
0.50
0.090
0.000
0.000
0.090
0.26
72
0.40
0.072
0.000
0.000
0.072
0.20
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28470 -1
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.85
[7] UNIT TIME - PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
100YR 24HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
4.5
[1 1] VARIABLE LOSS RATE (AVG) - INCHES /HO
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0
[13] CONSTANT LOSS RATE - INCHES PER HOQ
0
[14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[4 11181 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
100[5]
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOD
m
MAX
LOW
73
0.40
0.072
0.000
0.000
0.072
0.20
74
0.40
0.072
0.000
0.000
0.072
0.20
75
0.30
0.054
0.0001
0.000
0.054
0.15
76
0.20
0.036
0.0001
0.000
0.036
0.10
77
0.30
0.054
0.000
0.000
0.054
0.15
78
0.40
0.072
0.000
0.000
0.072
0.20
79
0.30
0.054
0.000
0.000
0.054
0.15
80
0.20
0.036
0.000
0.000
0.036
0.10
81
0.30
0.054
0.000
0.000
0.054
0.15
82
0.30
0.054
0.000
0.000
0.054
0.15
83
0.30
0.054
0.000
0.000
0.054
0.15
84
0.20
0.036
0.000
0.000
0.036
0.10
85
0.30
0.054
0.000
0.000
0.054
0.15
86
0.20
0.036
0.000
0.000
0.036
0.10
87
0.30
0.054
0.000
0.000
0.054
0.15
88
0.20
0.036
0.000
0.000
0.036
0.10
89
0.30
0.054
0.000
0.000
0.054
0.15
90
0.20
0.036
0.000
0.000
0.036
0.10
91
0.20
0.036
0.0001
0.000
0.036
0.10
92
0.20
0.036
0.000
0.000
0.036
0.10
93
0.20
0.036
0.000
0.000
0.036
0.10
94
0.20
0.036
0.000
0.000
0.036
0.10
95
0.20
0.036
0.000
0.000
0.036
0.10
96
0.20
0.036
0.000
0.000
0.036
0.10
1= 100%
F=
18.000
10484C
A/G STORAGE
OCF
U/G STORAGE
18.00 IN /HR *0.25= 4.50 "
4.50 " * 0.083 * 2.8400 ACRES=
1.0607 AC FT= 46206 CF
OCF
PERC LOSS IN 24 HRS
10484CF
PROVIDED
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
BASIC DATA CALCULATION FORM
PROJECT: LOT 27 TR287401
BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
3 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
5 AREA ACRES
2.8400
6 L- INCHES
-
[711--ADJUSTMENT FACTOR
-
[81L-MILES ([61"[71)
0.122
9 LCA - INCHES
-
10 LCA - MILES ( [71'[91
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - 12
311.00
14 S - FEET /MILE [13/[81
2549.18
15 S *'0.5
50.49
16 L *LCA/S''.5 ([8]-[10]/[15])
0.00003866
[171 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24-[17]-[16]--0.38)
(PLATE E -3
0.014
19 LAG TIME - MINUTES (60'[18])
0.86
20 25% OF LAG TIME (0.25-[191)
0.21
[21140% OF LAG TIME (0.40-[191)
0.34
[22] UNIT TIME - MINUTES (25 -[21])
24.66
RAINFALL DATA
1 SOURCE
IRCFCWCD
2 FREQUENCY -YEARS
1100YR 3HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
LQ
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
L91
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13]
AREA
SQ
INCHES
[14]
[13]
F [13]
[15]
AVG.
POINT
RAIN IN
2.80
-
-
2.80
3.40
-
-
3.40
4.50
-
-
4.50
F 5= - F 7= 2.80.
F 9= - F [ill=
3.40
7 13= - F 15= 4.50
[161 AREAL ADJ FACTOR 0.9
SEE PLATE E -5.8
0.9
0.9
[17] ADJ.AVG.POINT RAIN 2.52
([161' i [7],ETC)
3.06
4.05
RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28'
BY: AMG
DATE: 5/27/08
JOB #: 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
10
[6] LAG TIME - MINUTES
0.86
[7] UNIT TIME - PERCENT OF LAG (100 *[5] /[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 3HR
[10] TOTAL ADJUSTED STORM RAIN- INCHES
2.52
111 VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN/ HR
0
13 CONSTANT LOSS RATE- INCHES PER HOUR
0
[14] LOW LOSS RATE - PERCENT
I
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
[4 11181 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
6011011201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIO
m
100[5]
MAX
LOW
1
2.60
0.393
0.00
0.393
1.12
2
2.60
0.393
0.00
0.393
1.12
3
3.30
0.499
0.00
0.499
1.42
4
3.30
0.499
0.00
0.499
1.42
5
3.30
0.499
0.00
0.499
1.42
6
3.40
0.514
0.00
0.514
1.46
7
4.40
0.665
0.00
0.665
1.89
8
4.20
0.635
0.00
0.635
1.80
9
5.30
0.801
0.00
0.801
2.28
10
5.10
0.771
0.00
0.771
2.19
11
6.40
0.968
0.00
0.968
2.75
12
5.90
0.892
0.00
0.892
2.53
13
7.30
1.104
0.00
1.104
3.13
14
8.50
1.285
0.00
1.285
3.65
15
14.10
2.132
0.00
2.132
6.05
16
14.10
2.132
0.00
2.132
6.05
17
3.80
0.575
0.00
0.575
1.63
18
2.40
0.363
0.00
0.363
1.03
1 =100%
7= 15.12
10484 CF
A/G STORAGE
0 CF
U/G STORAGE 15.12 IN /HR *0.17= 2.52 "
PERC LOSS IN 3 HRS 2.52 " * 0.083 * 2.8400 ACRES=
PROVIDED 0.5940 AC FT= 25875.27 CF
0 CF
10484 CF
PROJECT: LOT 27 TR287401
BY: AMG
DATE: 5/27/08
JOB #: 06002
100YR /3HR
RAINFALL INTENSITY (IN /HR)
2.500
2.000
1.500
1.000
0.500
0.000
m-,m]-7R 7 Iff
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Q100 / 3HR
7.00
6.00
5.00
4.00
3.00
2.00
i
1.oa
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
RCFC &WCD'S SYNTHETIC UNIT HYDROGRAPH METHOD PROJECT: LOT 27 TR28740 -1
BASIC DATA CALCULATION FORM BY: AMG
DATE: 5/27/08
JOB #: 06002
[11 CONCENTRATION POINT
11
[21 AREA DESIGNATION
"B -2"
3 AREA - SQ INCHES
-
[41 AREA ADJUSTMENT FACTOR
-
[51 AREA -ACRES
2.8400
6 L- INCHES
-
[71L-ADJUSTMENT FACTOR
-
[811--MILES ([61-[71)
0.122
[91 LCA - INCHES
-
10 LCA - MILES ( [71'[91
0.016
[111 ELEVATION OF HEADWATER
360.00
[121 ELEVATION OF CONCENTRATION POINT
49.00
13 H- FEET 11 - l 21
311.00
14 S - FEET /MILE ([13/[81)
2549.18
15 S * *0.5
50.49
16 L *LCA/S * *.5 ([81-[101/[15])
0.00003866
17 AVERAGE MANNING "N"
0.015
18 LAG TIME - HOURS (24'[17]'[16]--0.38)
(PLATE E -3
0.01427451
[191 LAG TIME - MINUTES (60-[18])
0.86
20 25% OF LAG TIME (0.25-[191)
0.21
[21140% OF LAG TIME (0.40-[191)
0.34
[22] UNIT TIME - MINUTES (25 -[21])
24.66
RAINFALL DATA
1 SOURCE
IRCFCWCD
[21 FREQUENCY - YEARS
1100YR 6HR
[3] DURATION:
3 HOUR
6 HOUR
24 HOUR
[4]
POINT
RAIN
INCHES
[5]
AREA
SQ
INCHES
[6]
f5�
F [5]
[7]
AVG.
POINT
RAIN IN.
[8]
POINT
RAIN
INCHES
[9]
AREA
SQ
INCHES
[10]
f9]
F [9]
[11]
AVG.
POINT
RAIN IN.
[12]
POINT
RAIN
INCHES
[13] [14]
AREA [13]
SQ F [13]
INCHES
[15]
AVG.
POINT
RAIN IN
2.80
1
2.80
3.40
-
-
3.40
4.50
-
-
4.50
7 5= 15.45 F 7= 280
E 9= 19.7 F 11 =
3.40
F 13= 19.7 F 15= 4.50
16 AREAL ADJ FACTOR .9
SEE PLATE E -5.8
0.9
0.9
.52
[17] ADJ.AVG.POINT RAIN E]6
([16]* E [7],ETC)
3.06
4.05
RCFC BWCD'S SYNTHETIC UNIT HYDROGRAPH METHOD
UNIT HYDROGRAPH AND EFFECTIVE RAIN CALCULATION SHEET
PROJECT: LOT 27 TR28740 -1
BY: AMG
DATE: 5/27/08
JOB* 06002
[1] CONCENTRATION POINT
11
[2] AREA DESIGNATION
"B -2"
[3] DRAINAGE AREA - ACRES
2.8400
[4] ULTIMATE DISCHARGE - CFS - HRS /IN (645 *[31
N/A
[5] UNIT TIME - MINUTES
15
[6] LAG TIME - MINUTES
0.86
[7] UNIT TIME - PERCENT OF LAG (100'[5]/[6])
N/A
[8] S -CURVE
DESERT
[9] STORM FREQUENCY & DURATION
1 OOYR 6HR
[10] TOTAL ADJUSTED STORM RAIN - INCHES
3.06
1[111 VARIABLE LOSS RATE (AVG) - INCHES /HOUR
0
[12] MINIMUM LOSS RATE (FOR VAR. LOSS) -IN /HR
0.21
1(131 CONSTANT LOSS RATE- INCHES PER HOUR
0
1 [14] LOW LOSS RATE - PERCENT
0
UNIT HYDROGRAPH
15
[16]
TIME
PERCENT
OF LAG
[7] *[15]
[17]
CULMULATIVE
AVERAGE
PERCENT OF
ULTIMATE
DISCHARGE
(S- GRAPH)
[18]
DISTRIB.
GRAPH
PERCENT
[17]m-
[17]m -1
[19]
UNIT
HYDROGRAPH
CFS - HRS /IN
4' 18
100
[20]
PATTERN
PERCENT
(PL E -5.9)
[21]
STORM
RAIN
IN /HR
60[101[201
[22]
LOSS
RATE
IN /HR
[23]
EFFECTIVE
RAIN
IN /HR
[21] -[22]
[24]
FLOW
CFS
UNIT
TIME
PERIOC
m
100[5]
MAX
LOW
1
1.70
0.208
0.00
0.00
0.21
0.6
2
1.90
0.233
0.00
0.00
0.23
0.7
3
2.10
0.257
0.00
0.00
0.26
0.7
4
2.20
0.269
0.00
0.00
0.27
0.8
5
2.40
0.294
0.00
0.00
0.29
0.8
6
2.40
0.294
0.00
0.00
0.29
0.8
7
2.40
0.294
0.00
0.00
0.29
0.8
8
2.50
0.306
0.00
0.00
0.31
0.9
9
2.60
0.318
0.00
0.00
0.32
0.9
10
2.70
0.330
0.00
0.00
0.33
0.9
11
2.80
0.343
0.00
0.00
0.34
1.0
12
3.00
0.367
0.00
0.00
0.37
1.0
13
3.20
0.392
0.00
0.00
0.39
1.1
14
3.60
0.441
0.00
0.00
0.44
1.3
15
4.30
0.526
0.00
0.00
0.53
1.5
16
4.70
0.575
0.00
0.00
0.58
1.6
17
5.40
0.661
0.00
0.00
0.66
1.9
18
6.20
0.759
0.00
0.00
0.76
2.2
19
6.90
0.918
0.00
0.00
0.92
2.6
20
7.50
1.297
0.00
0.00
1.30
3.7
21
10.60
1.775
0.00
0.00
1.77
5.0
22
14.50
0.416
0.00
0.00
0.42
1.2
23
3.40
0.122
0.00
0.00
0.12
0.3
24
1.00
0.122
0.00
0.00
0.12
0.3
10484 CF
A/G STORAGE
0 CF
U/G STORAGE
0 CF
PERC LOSS IN 6 HRS
10484 CF
PROVIDED
7-=100%
F= 6.87
6.87 IN /HR *0.25= 1.7167 "
1.7167 " * 0.083 * 2.8400 ACRES=
0.4047 AC FT= 17626.60 CF
PROJE•:,T: LOT 27 TR28740 -1
3Y: AMG
DATE: 5/27/08 100 YR /6 HR
JOB M 06002
RAINFALL INTENSITY (IN /HR)
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Q100 /6HR
6.0
5.0
4.0
3.0
2.0
1.0
0.0
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 3HR
25875.27 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
2.6
672.76
0.00
0.00
2
2.6
672.76
0.00
0.00
3
3.3
853.88
0.00
0.00
4
3.3
853.88
0.00
0.00
5
3.3
853.88
0.00
0.00
6
3.4
879.76
0.00
0.00
7
4.4
1138.51
0.00
0.00
8
4.2
1086.76
0.00
0.00
9
5.3
1371.39
0.00
0.00
10
5.1
1319.64
0.00
0.00
11
6.4
1656.02
780.78
1.30
12
5.9
1526.64
1526.64
2.54
13
7.3
1888.89
1888.89
3.15
14
8.5
2199.40
2199.40
3.67
15
14.1
3648.41
3648.41
6.08
16
14.1
3648.41
3648.41
6.08
17
3.8
983.26
983.26
1.64
18
2.4
621.01
621.01
1.04
F=
25875.27
8
SHT 1 OF 5
0
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 6HR 17626.60 CF PER SUH
- PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
1.7
299.65
0.00
0.00
2
1.9
334.91
0.00
0.00
3
2.1
370.16
0.00
0.00
4
2.2
387.79
0.00
0.00
5
2.4
423.04
0.00
0.00
6
2.4
423.04
0.00
0.00
7
2.4
423.04
0.00
0.00
8
2.5
440.67
0.00
0.00
9
2.6
458.29
0.00
0.00
10
2.7
475.92
0.00
0.00
11
2.8
493.54
0.00
0.00
12
3.0
528.80
0.00
0.00
13
3.2
564.05
0.00
0.00
14
3.6
634.56
0.00
0.00
15
4.3
757.94
0.00
0.00
16
4.7
828.45
0.00
0.00
17
5.4
951.84
0.00
0.00
18
6.2
1092.85
0.00
0.00
19
6.9
1216.24
620.76
0.69
20
7.5
1322.00
1244.23
1.38
21
10.6
1868.42
1868.42
2.08
22
14.5
2555.86
2555.86
2.84
23
3.4
599.30
599.30
0.67
24
1.0
176.27
176.27
0.20
Z=
17626.60
t
SHT 2 OF 5
r
i
r
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
1
0.20
92.41
0.00
0.00
2
0.30
138.62
0.00
0.00
3
0.30
138.62
0.00
0.00
4
0.40
184.82
0.00
0.00
5
0.30
138.62
0.00
0.00
6
0.30
138.62
0.00
0.00
7
0.30
138.62
0.00
0.00
8
0.40
184.82
0.00
0.00
9
0.40
184.82
0.00
0.00
10
0.40
184.82
0.00
0.00
11
0.50
231.03
0.00
0.00
12
0.50
231.03
0.00
0.00
13
0.50
231.03
0.00
0.00
14
0.50
231.03
0.00
0.00
15
0.50
231.03
0.00
0.00
16
0.60
277.24
0.00
0.00
17
0.60
277.24
0.00
0.00
18
0.70
323.44
0.00
0.00
19
0.70
323.44
0.00
0.00
20
0.80
369.65
0.00
0.00
21
0.60
277.24
0.00
0.00
22
0.70
323.44
0.00
0.00
23
0.80
369.65
0.00
0.00
24
0.80
369.65
0.00
0.00
25
0.90
415.85
0.00
0.00
26
0.90
415.85
0.00
0.00
27
1.00
462.06
0.00
0.00
28
1.00
462.06
0.00
0.00
29
1.00
462.06
0.00
0.00
30
-1.10
508.27
0.00
0.00
31
1.2
554.47
0.00
0.00
32
1.30
600.68
0.00
0.00
33
1.50
693.09
0.00
0.00
34
1.50
693.09
318.62
0.35
35
1.60
739.30
739.30
0.82
36
1.70
785.50
785.50
0.87
37
1.90
877.91
877.91
0.98
38
2.00
924.12
924.12
1.03
39
2.10
970.33
970.33
1.08
40
2.20
1016.53
1016.53
1.13
41
1.50
693.09
693.09
0.77
42
1.50
693.09
693.09
0.77
43
2.00
924.12
924.12
1.03
44
2.00
924.12
924.12
1.03
45
1.90
877.91
877.91
0.98
46
1.90
877.91
877.91
0.98
r
SHT 3 OF 5
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5/27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
47
1.70
785.50
785.50
0.87
48
1.80
831.71
831.71
0.92
49
2.50
1155.15
1155.15
1.28
50
2.60
1201.36
1201.36
1.33
51
2.80
1293.77
1293.77
1.44
52
2.90
1339.97
1339.97
1.49
53
3.40
1571.00
1571.00
1.75
54
3.40
1571.00
1571.00
1.75
55
2.30
1062.74
1062.74
1.18
56
2.30
1062.74
1062.74
1.18
57
2.70
1247.56
1247.56
1.39
58
2.60
1201.36
1201.36
1.33
59
2.60
1201.36
1201.36
1.33
60
2.50
1155.15
1155.15
1.28
61
2.40
1108.94
1108.94
1.23
62
2.30
1062.74
1062.74
1.18
63
1.90
877.91
877.91
0.98
64
1.90
877.91
877.91
0.98
65
0.40
184.82
184.82
0.21
66
0.40
184.82
184.82
0.21
67
0.30
138.62
138.62
0.15
68
0.30
138.62
138.62
0.15
69
0.50
231.03
231.03
0.26
70
0.50
231.03
231.03
0.26
71
0.50
231.03
231.03
0.26
72
0.40
184.82
184.82
0.21
73
0.40
184.82
184.82
0.21
74
0.40
184.82
184.82
0.21
75
0.30
138.62
138.62
0.15
76
0.20
92.41
92.41
0.10
77
0.30
138.62
138.62
0.15
78
0.40
184.82
184.82
0.21
79
0.30
138.62
138.62
0.15
80
0.20
92.41
92.41
0.10
81
0.30
138.62
138.62
0.15
82
0.30
138.62
138.62
0.15
83
0.30
138.62
138.62
0.15
84
0.20
92.41
92.41
0.10
85
0.30
138.62
138.62
0.15
86
0.20
92.41
92.41
0.10
87
0.30
138.62
138.62
0.15
88
0.20
92.41
92.41
0.10
89
0.30
138.62
138.62
0.15
90
0.20
92.41
92.41
0.10
91
0.20
92.41
92.41
0.10
92
0.20
92.41
92.41
0.10
4
J
SHT 4 OF 5
DISCHARGE ANALYSES OF LOT 27 OF TRACT 28740 -1
BY: AMG
DATE: 5 /27/08
JOB #: 06008 AVAILABLE STORAGE= 10484.00 CF
100 YR 24HR
46206.00 CF PER SUH
PERIOD
% OF STORM
VOLUME
OVERFLOW
Q100
93
0.20
92.41
92.41
0.10
94
0.20
92.41
92.41
0.10
95
0.20
92.41
92.41
0.10
96
0.201
92.41
92.41
0.10
Z=l
46206.00
J
SHT 5 OF 5
HI Egifi.lorM
99 M ig IN
10
8
6
5
4
3
2
H
W
W 1
Q
3 0.8
0
I- 0.58' 0.6
0- LOT 27
w 0.5
o
0.4
0.3
0.2
0.12'
PARCEL 1
0.1
1
a
N
4 X 0.8 X 0.5 BLOCKAGE
ro
2 3 4 5 6 8 10 20 30 40 50 60 80 100
2.7 CFS 6.05 CFS
PARCEL 1 LOT 27 g
DISCHARGE Q (FASEC)
GRATE INLET CAPACITY IN SUMP CONDITION
(SOURCE USDOT - FHWA - HEC-1 2,1984)
FA
GRATE OPENING RATIO
• P_ 1-1/8 0.6
Reticuline 0.8
• Curved Vane 0.33
30* Tilt -Bar 0.34
Tested
on
WANIFAVIVA
PAPA
'A",
MEFWAA
FAIN
wwo.
Z 2,30,
CURB
31
�—L=r I
A= CLEAR OPENING AREA
ppIr
01(a
A
IPA
P,
2 3 4 5 6 8 10 20 30 40 50 60 80 100
2.7 CFS 6.05 CFS
PARCEL 1 LOT 27 g
DISCHARGE Q (FASEC)
GRATE INLET CAPACITY IN SUMP CONDITION
(SOURCE USDOT - FHWA - HEC-1 2,1984)
FA
/
//_ - --
/ /
S
PI�OPO ED RQ6K FALL WAL
/(SEE /5HEET OR SECTION
-
/ / / / / / / /j/ PRO SED DETENTION BASIN
-
/j % / / /%/
LOT 27 °ACCT 28740-1
PROPOSED PRECAST �41,- SQ. CA TCH 8� ,SIN rn W// PARKWAY GRATE OOKS OR APP D EQUAL); (SEE SHEET 3 FOR DILS) -
j //j ACTUAL EXISTING TOE OF MOUNTAft j _
1- `I1/ r / - _ I PER FIELD SURVEY DATA
i
rj
L
or r
\ PROPOSED 12" CCP STORM ,DRAIN r
P I
GRAPHIC SCALE
/ - - 40-- 0 20 40 80
IN rTr )
1 inch = 40 M SHEET 1
m m m= m m = == m == m= i == m
zx
TOE =OF' MOUNTAIN
-PER TRACT tvFAP -- ` \� �\�\ �� \\ �\� / ///
_ -
PER, AT.0 / LXFSTING TOE.F MOUNTAIN- // i
I�1� = SURVEY =DATA_ -�
_ _ _- �.����\�\��;� ;= '7 /�j /• /j // / /�/ / /// / � .� \ "� \� �� �� �\\\\ " / / // J/ / 1.1 // \ \ Cr/j
LQT 277
PARCELI
PROPOSED ROCK FALL WAL
(SEE SHEET 4 FOR SECTION
a I \ L����` �/� ----------------- - - - - -- - -
12 STORM DRAI - - -
PROP �D_ _ - - CCP_
CE
/ 06 , / PEERLESS — /
cd
�— = =w. _ -_ �'ROPOS PR AST 4"-,S CA H B6SIN -
- - - _ - _ - -PAR VIFprY BROO 0 APP EQUAL), -
t Kok -___�
i/ SHEET
CATCH BASIN DETAIL
NTS
R/W & BACK OF CURB
a 129; ,
NPoL
W2.
129,E -0�-
a
PROPOSED ROCK F LL WALL-
PROPOSED DETENTIO BASIN D =2'
6" CURB AROUND CATCH BASIN
12" DIA CCP STORM DRAIN PIPE -
PROPOSED PRECAST CATCH BASIN
(BROOKS OR APPROVED EQUAL)
ACTUAL EXISTING TOE OF MOUNTAIN
!0pVE PER FIELD SURVEY DATA
_I I
I I
SHEET 3
WALL SECTION DETAIL
NTS
PROPOSED ROCK FALL WALL
V)
z
O
�o
z
om F6
Y W
U �
WO
Ix ui w
CL
w
2 a
ui as
a
EXISTING MOUNTAIN
a z
O
z D
W z
N 10' MINIMUM'
a
] 1I—
SHEET 4
N THE CITY OF LA 7JINTA COUNTY OF RNERSM STATE OF CAEIOR.Hu
PARCEL MAP iVO. 32891
BENS A SU9DWSION OF EDT 31 Of TRACT 26611 AS SHOW4 N WP BOOK 269. PAGES 12 THROUGH 17, 91ELUSIE. RECORDS OF
RNERSIDE COUNTY. STATE OF GWFORR'A AND CITY OF LA OUNIA LOT UNE ADJUSTMENTS 99 -296 AND 99 -299 RECORDED MARCH
W6, 1999 AS INSTRUMENTS 112019 THROUGH 112051, DaUSNE, RECORDS OF SAID RNERSIOE COUNTY.
KELLEHER MAPPING FEBRUARY 2006
ftwors
� Iona. m nw w S M owes v M sA.O sW` 10 .0 M 51-u 10 so ro4a:
a K APL 0 0KT ,0 w of Oa6M S ALCOSVM1 M a0 A C1UR 11111 10 SMD I.vO, ,IAU
w W 6w f0 M R.R10 40 QOOOeF x nrs SUDOA9a1 W .s R� wnp M Da'T17,nE
Oa✓arR Vi.
R IOKOl ROOAE NR M UNI 7R47rt ? aRAA'+Ei OW AOOasO+i .Z.W . W- AM
fA90[M •6D DO ARt .PU w rfW[iun w ryEEl , N 510w %G¢Gw
/
IRl l /
1� D
i
1
a iMS -!- Olt at .�T.A+ IDOL 1QORE RE
. A WAft K" w .0 1Cn SAO SviL POW— APKWU
lue c�2dr
q° sir W'AW iiw rae3�sAaE®;mA1ro +ro�.ob q�loai�l,ltwv,
SOM1 W 11 a a[ rstmA[1rt M R45a4. OAR M onm 1NRN w1o. M RD4aAp .cot.
oaaImt1[.411eAOn.
wn[ss w u10.
mun1K S r1 Xi1//Rf� ..ww,�t� -�-�Etw;r.
wR.w, r a .10 OI W• w OTMT01 [10Ym JlJ_Yr��
S►W
R"A SVA4 -*03
t Z"V;rEFY &WERE 1b"fV WRKT#oly UNDER PANTS of
i8C SWATH DF CAUfomth 1w UE Fort�1119 PALS ^ Es
iRAIE •K D <ALM42CT.
10®E «Rm 1141 .00014" 10 M RCO[4 Or xi mm As w ne WE 1104 ARE AO LAM
M w171vr 5 a M wild W M u V1 X 07Ow, ADS6ORA1. Sw m TARS OR
. ova �.sstspcvm+s� —V= .s -M D . 1. 0 tuna
77UECnt AS 1A4S D7+
AOE e1O1 A4 IS,SRnD M LL w5
GSD F11. \\ 1776 D.CE 000MM1 1Y Eg3EC10R
1 MRA' 03"" 1181 . COO. M AY 7 �t0. 4QQ��.� As 7El\ OdOAV V 1W wWR
M b.Rw x aATUSans 7r M D7 , x "WRwW OOdRWD UNA M rllpet y
u ORi T•L 071r1h, RU.CRAL, T Sx'A..1O Al 1RM A9a77510OS .\LLGRC .s rani
.T. 1K 7 1MR0 O nas W 1:n1 M fOUDTT RNPDIA .Pi . IAM 1EM'. • tA0 r.(RRn DU, w
T r.Ylaf Aq SAD WO N4 l6`1 OA• Af.aP� w 5.0 BOlO O SOS ": .+5.
O".JA , t7Q�
CO.
p- LM LW f
04. O [RA57RS
M BORO O 9A
6f� A
SrNAAM OMISSIONS
11/tsyw: M aulu" wM w M sumnsa. W CT. M scnlWIMS Dr M tOUQAM
Ow4As O use .s w0 /71 OMR aIUdST . O[[R W,TED.
Y11DOA XRbS 1ER0 OY.R, .OAw O M Ow" LO IW O(1 M 1ENi0 :O7aw IA
OA M S1A act 1!1 O SODS
7 RA=E � a w W" M 01D5 WSOO Zbm 25 11X, . 777 at.
a E 1V Dw
IAM F v O All1KA 1OLU O w L"aw. 101 . w,O PRO[ HCOW .Oanw111A low
6JOC —A. P 01 Qw
W17 u a.M11mw a Woon 1a n.a1E w.RS ,ms A10 U9En 01 ORIO%
4 O - ORQOwr Ml 9 a' Ow 7R M W O 1q[, .I. r 14WWC,
..2a
RECORDER'S STATEMEW
rttED
TWT 1i:e„ n �. a bDDRy`L__ d owm wvs. Ar
C 5s]_s aC r THE REOUESr or
LNE Ott tAt1M OF lIQ Cfly OF u OWrtw
10rEE , 7y7IlR - OOi.�O�'O
1ARRW W..ARD. COUllW ASSESSOR - CLERS - RECORDER
BI:� -E _. DERItt
AlBDM40H olmw CE:
rOEUIr NATlOKAL ME aSURARCE CO PA \Y
nrl W RAS PW.= P R On UADER w DwODfW, wo ..s W WID IWY . MZl VA41 a
011w —Ax " M REWWW 1s O M D6O1,90R W .C, w1O IC VI ]NrWff 4 M 4Q.6,
Or rVADffO* CM .O4H VA/E 41 .W .6 Axis � Gr W OVA" MO 441Rr M tO5n04 .00M. IN RM
BE SU w W an W .CaRAAt[ V TAO I S10 1171A.A7R awl wC
sVTo011 M Wat M 9A," 10 a At1AYED ma nW ro Pr /Im SAf1CYfM..
aDwoba M M Acc.o[D WODOR.a AR.Roqu ,ORATE W. r w. 0 EAAO
[ autb -m 666
LS 1 a l 8 P QP
Oa[ al -� v NO, '07
w
D4wAno. o•iu a -w-ro
� E. 7a/xro V
1�W,SU4 Mil M4 OAlam M.].1W O111100W I1O1779540l9OR 1414
4oul 7 "Rol. W14 9S, 2= H SAf .S rt A11TN0 } M Ip'.T[ W, r ...011c
KIW 100 DOE7: DRS wl PR7'906 J M SLZ A1D1197 YV KI MD M1 :7Gt 70CIMR0 nt[
Ww\m wA QPpFE �f
a
1w R. rE e: Ul11
roes ,7wJ [v.1A/AA1s it
OA O171P �
� B�ti Tr�Di 1F
drr suRMTYOft'S STATDMff OF
1 1fAEB+ St.,E i1yT 1 1MfS DIURPm M wP'1. W 01 R.PCR w RO, us"
E054tr O 2 51([13 .10 1 w L!6<h :MAr 510 W S ,Eae.GLL1 R. k
77
E w M\SOV LS. 5561 —E ! SSD
IMO Ott SOR44OR
ON QMK STAteldT
M [RORU 1 WPlTI) A . a MM TAO E.-Or.0 WM O M Ott M0 O n. 71r O V
a.R1f aOPA KMHT SLAB AAt S.D Ott 00/14 w1111 R1DAM 1[LO10'0✓ :w r�,f'� CAt
M .MI W O" PWOS W J1DT
W
011L o 1 .w D•rt
OR7. O„ OOa
ar M o,r O u O.wiA
CIT, Di,:, ::.ETA
Plan 301 No. 1
D 02
Roj
. :,.c ?a9CC31 fF4CR2� o
NORI'q 4��bCg�q�t�LO•� -• � �
�� ait: -tq:y @i.IIs
Hit • 4 ?$3:::x:23 ?g:eaoo:ao_�
� °^ •'/ r���'���yt��. ���� 7 •'c.•j• 48aE \ ��������f���A��I �ib1��.}��
ao
#3 i yam, � tj. a.. =u Ca Y006 �o:6i3
�^r• �� Apr ° � � �/
P�R °X n� s
m• r
vNTi - aS Z
--------- - - - - --
•• io °..' e a 4 u R c o 'O
... �� 88 € m R
WIN N)
/' gip` �•s I 0 (50
En
ft
p •
Z• soave �• a
r 6¢s a`•' •,'�° a° aW'�g
N Z \
N
U►
SCALE 1' -40•
- IN OIE OTT OF LA W.41A. COUNTY OF RIWY4M. STATE 7 C.Va Ulflll
V
� Tom
PARCEL MAP NO. 32891
Rplg
n
arlrat
{I.I+(lt)
SEE SLEET 2 FOR SURWYOR'S NOTES
a
.,runt
Wr
SUNG A SUBDMSON OF LOT SA OF TRACT 28611 AS SHOWN IN WP BOOK 269. PAGES 12 THROUGH 17• INCLUSK. RECORDS Of
0,40 8A4S OF BEARING
t1
MINI
212
RNERSIOE CXRM, STAT£ OF CALtr0R1M AND COY OF LA OIFNTA LOT UN£ ADAWKI TS 99 -298 AND 99 -299 RECORDED UA!"
a
o
nnral
les,o'pti
{M'
a{r
18. 1999 AS D5TRU17ENrS 112049 THROUGH 112051. DaCIUSni. RECORDS OF SAID RNERSIDE COUNTY,
.ran
oea
KEUEHER MAPPING FEBRUARY 2006
oun[ tAtr
TI
.4Ttrat
a.tr
-
'JQJ eae lecl nrort
a
w....jn
w.a•
u Irlrlr .Iry ,a{r . all,
n
ll{
arlrAtt
.pY1Ct
wv-
Y6Y
-
m OZ,S:lr "Im al{• YAa
'Win
WIT'r Qlw "M all.
of
rlrxv
a
u .Wlr aw I;m {or
n tan {1r aw Ter um
n1
n�
t�IbIOT
.1.1xv
Icl•
„LSS
.
a Ve{pt• aw aw af0'
Ia
"min
r)F'
.
C) .J"r xlrr' .)rr 1),If
11{
tmmi
Ix
0 antb• MIN aY air
la
ami.1
OA
.
Q O nr 91w• elr jr I
C wynr IUa 1t a• II.1r
IV
,Ir
l Wul
.we rat
."',
1.
Cl', , wsb' Nra >fY IIIY
IN
IN
t.min
..r
-.W
Ca I{l.a' Is, ,tr i♦,fY
n1 www Nm Aw :Ira
4t
W011n
We
.
C,I 3711.4' llAra ll w alr
I
I is
`
1
I um, IaM1 St.Y VS'�aarts
A9 Ar/'.r -I u OJCA tm ul 4ASTA10
r{-30, . bt XU
a Mr. tOi 1n0I A n1pY.
� C
�II
O
�7
1r
• 9' PARCEL 2
law 9
'L 1
I ; v Ism K
1
1 i
a r,
xxyx-w
r
N G PARCEL 1
7`
9
smt (/1 r Loa
0m K
1m/IA -v �. «
1 a
n_
Im AI
t I AANYI
w xvx w
Plan Sye�t/Njo. 1
2