HomeMy WebLinkAboutCT 08-07; DRAINAGE STUDY; 2011-12-29DRAINAGE STUDY
U
La Costa Town Square
Office
Job No. 10-1290
December 29, 2011
Prepared For:
PROPERTY DEVELOPMENT CENTERS
5918 Stoneridge Mall Road
Pleasanton, CA 94588
(925) 738-1232
Prepared by:
FESSil 19
O'DAY CONSULTANTS, INC. A.
2710 Loker Avenue West Suite 100
Carlsbad, California 92008-6603 Uj
Tel: (760) 931-7700 EXP Ali ~Ik Fax: (760) 931-8680
CNIV
0
12—
Nichole A. Fine RCE 70035 Date
Exp. 09/30/12
1
I Declaration of Responsible Charge
I hereby declare that I am the Engineer of Work for this project, that I have exercised responsible
charge over the design of this project as defined in section 6703 of the Business and Professions
- Code, and that the design is consistent with current standards.
I understand that the check of project drawings and specifications by the City of Carlsbad is
confined to a review only and does not relieve me, as the Engineer of Work, of my
responsibilities for the project design.
- O'Day Consultants, Inc.
P
2710 Loker Avenue West, Suite 100
Carlsbad, CA 92010
(760) 931-7700
'V1ce&r - Date:
Nichole A. Fine
R.C.E. No. 70035 Exp. 9/30/12
OFESS
C 70035
* EXP. W *4 oil L,,4kZL0FCAV
-
2
TABLE OF CONTENTS
Section Description
Introduction and Project Description
Hydrology
Appendix 1- 100 Year Hydrologic Calculations for Existing Conditions
Appendix 2- 100 Year Hydrologic Calculations for Mass Grading
Appendix 3- 100 Year Hydrologic Calculations for Ultimate Conditions
Page No.
4
4-7
5-15
16-35
36-57
N Exhibits
Exhibit A - Vicinity Map
Exhibit B - Table 3-1 Runoff Coefficients For Urban Areas (RationalMethod)
Exhibit C - Soil Group Map per USDA NRCS
Exhibit D - 100-year 6-hour precipitation map
Exhibit E - 100-year 24-hour precipitation map
Exhibit F - Figure 3-3 Urban Areas Overland Time of Flow Nomagraph
Exhibit G - Figure 3-1 Intensity Duration Design Chart
Exhibit H - Table 3-2 Maximum Overland Flow Length & Initial Time of
Concentration
Exhibit I - Fig. 3-4 Nomograph of Tc for Natural Watersheds
Exhibit J - 100-Scale Existing Conditions Hydrologic Map (Map Pocket)
Exhibit K - 40-Scale Proposed Conditions Hydrologic Map (Map Pocket)
3
A. INTRODUCTION AND PROJECT DESCRIPTION
This drainage study was prepared to support grading plans for the Office at La Costa Town
Square. The project is located south and east of Rancho Santa Fe Road and North of La Costa
Avenue in the City of Carlsbad, California. The site is generally described as mostly undisturbed
vacant land with the exception of small borrow and stockpile sites for the grading and
improvements of Rancho Santa Fe Road and La Costa Avenue per City of Carlsbad drawing
409-4B. The disturbed areas have since been revegetated. The site is steep with well-defined
drainage courses and generally slopes toward the south with slopes ranging from 10% along the
northern portion to 18% southerly. There are several drainage courses with steep side slopes
- greater than 40%. See Exhibit 'A' for a Vicinity Map of the site.
Site runoff enters the City's MS4 along La Costa Avenue and combines with flows from
- surrounding developments before discharging to a regional detention facility. Mitigated flows
then enter an unnamed conveyance system which enters Encinitas Creek approximately 1.9 miles
downstream. It then enters Batiquitos Lagoon about 1.6 miles further.
The site will be graded at 2% minimum towards the center of the site. A future site plan is
unknown at this time. It is assumed that the future office site will consist of parking lots and
buildings and will be typical of the general commercial run-off coefficient.
B. HYDROLOGY
Hydrologic calculations were performed utilizing the San Diego County Rational Method as
- described in the San Diego County Hydrology Manual, June 2003. Pertinent exhibits from the
San Diego County Hydrology Manual are enclosed for reference, as follows:
Exhibit B - Runoff Coefficients (Table 3-1) & Calculated Coefficients
Exhibit C - Soil Group Map
Exhibit D - 100-year 6-hour Isopluvial Map
Exhibit E - 100-year 24-hour Isopluvial Map
Exhibit G - Intensity-Duration Design Chart
Exhibit F - Rational Formula-Overland Time of Flow Nomograph
11
APPENDIX 1
100 Yr. Existing Hydrologic Calculations
(See Exhibit 'J')
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San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (C) 2004 Version 3.2
Rational method hydrology program based on
- San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/29/07
-----------------------------------------------------------------------
LA COSTA TOWN SQUARE
BASIN A - EXISTING CONDITIONS
G:\ACCTS\001017\1017A.OUT
********* Hydrology Study Control Information
- O'Day Consultants, San Diego, California - SIN 10125
Ra:ional hydrology study storm event year is 100.0
May data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
Adjusted 6 hour precipitation (inches) = 2.800
P5/P24= 54.9%
San Diego hydrology manual 'C' values used
Runoff coefficients by rational method
+++++++++++++++++-+++++++++++++++++++++++++++++++++++1++++++++++++++++
Process from Point/Station 100.000 to Point/Station 100.000
*k** USER DEFINED FLOW INFORMATION AT A POINT **** PER DWG. 368-2C,
SHT. 15
User specified 'C' value of 0.800 given for subarea
Rainfall intensity (I) = 3.797 for a 100.0 year storm
User specified values are as follows:
TC = 14.00 mm. Rain intensity = 3.80(In/Hr)
Tonal area = 19.50(Ac.) Total runoff = 63.50(CFS)
Process from Point/Station 100.000 to Point/Station 311.000
IRREGULAR CHANNEL FLOW TRAVEL TIME ****
Estimated mean flow rate at midpoint of channel = 89.388(CFS)
Depth of flow = 1.482(Ft.), Average velocity = 10.181(Ft/s)
Irregular Channel Data ***********
-----------------------------------------------------------------
Information entered for subchannel number 1
Point number 'X' coordinate 'Y' coordinate
1 0.00 2.50
2 10.00 0.00
n.
3 20.00 2.50
Manning's 'N' friction factor 0.040
-----------------------------------------------------------------
Sub-Channel flow = 89.389(CFS)
flow top width = 11.852 (Ft.)
velocity= 10.181(Ft/s)
area = 8.780(Sq.Ft)
Froude number = 2.085
Upstream point elevation = 383.000(Ft.)
Downstream point elevation = 285.000(Ft.)
Flow length = 840.000(Ft.)
Travel time = 1.38 mm.
Time of concentration = 15.38 mm.
Depth of flow = 1.482(Ft.)
Average velocity = 10.181(Ft/s)
Total irregular channel flow = 89.388(CFS)
Irregular channel normal depth above invert elev. = 1.482(Ft.)
Average velocity of channel(s) = 10.181(Ft/s)
Sub-Channel No. 1 critical depth = 1.984(Ft.)
critical flow top width = 15.875 (Ft.)
critical flow velocity= 5.675(Ft/s)
critical flow area = 15.751(Sq.Ft)
Adding area flow to channel
- User specified 'C value of 0.350 given for subarea
Rainfall intensity = 3.575(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 19.893(CFS) for 15.900(Ac.)
- Total runoff = 83.393(CFS) Total area = 35.40(Ac.)
+++++++++++++++++-++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 311.000 to Point/Station 312.000
PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 285.53 (Ft.)
Downstream point/station elevation = 282.84 (Ft.)
Pipe length = 55.56 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 83.393(CFS)
Given pipe size = 24.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
21.270(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 7.547(Ft.)
Minor friction loss = 16.412(Ft.) K-factor = 1.50
Pipe flow velocity = 26.54 (Ft/s)
Travel time through pipe = 0.03 mm.
Time of concentration (TC) = 15.41 mm.
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Process from Point/Station 311.000 to Point/Station 312.000
**** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 1
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7
Stream flow area = 35.400 (Ac.)
Runoff from this stream = 83.393(CFS)
Time of concentration = 15.41 mm.
Rainfall intensity = 3.569(In/Hr)
Process from Point/Station 401.000 to Point/Station 402.000
INITIAL AREA EVALUATION
User specified 'C' value of 0.350 given for subarea
Time of concentration computed by the
natural watersheds nomograph (App X-A)
TC = [11.9*1engthMi)3)/(elevation change)] 385 *60(min/hr) + 10 mm.
Initial subarea flow distance = 240.00(Ft.)
Highest elevation = 373.00(Ft.)
Lowest elevation = 358.00(Ft.)
Elevation difference = 15.00(Ft.)
TC=((11.9*0.0455E)/( 15.00)]".385= 1.55 + 10 mm. = 11.55 mm.
Rainfall intensity (I) = 4.300 for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.090(CFS)
Total initial stream area = 0.060 (Ac.)
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + . + + + + + + + + + + + + + + + + + . + +
Process from Point/Station 402.000 to Point/Station 403.000
IRREGULAR CHANNEL FLOW TRAVEL TIME
Estimated mean flcw rate at midpoint of channel = 0.873(CFS)
Depth of flow = 0.188(Ft.), Average velocity = 2.458(Ft/s)
Irregular Channel Data
-----------------------------------------------------------------
Information entered for subchannel number 1
Point number 'X' coordinate 'Y coordinate
1 0.00 2.00
2 20.00 0.00
3 40.00 2.00
Manning's 'N' friction factor = 0.040
-----------------------------------------------------------------
Sub-Channel flow = 0.873(CFS)
flow top width = 3.769 (Ft
velocity= 2.458(Ft/s)
area = 0.355(Sq.Ft)
Froude number = 1.411
Upstream point elevation = 358.000(Ft.)
Downstream point elevation = 285.000(Ft.)
Flow length = 710.000(Ft.)
Travel time = 4.81 mm.
Time of concentration = 16.36 mm.
Depth of flow = 0.188(Ft.)
Average velocity = 2.458(Ft/s)
Total irregular channel flow = 0.873(CFS)
Irregular channel normal depth above invert elev. = 0.188(Ft.)
Average velocity cf channel(s) = 2.458(Ft/s)
Sub-Channel No. 1 critical depth = 0.217 (Ft.)
critical flow top width = 4.336(Ft.)
critical flow velocity= 1.857(Ft/s)
critical flow area = 0.470(Sq.Ft)
Adding area flow to channel
User specified 'C value of 0.350 given for subarea
Rainfall intensity = 3.435(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 1.250(CFS) for 1.040(Ac.)
Total runoff = 1.340(CFS) Total area = 1.10(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 403.000 to Point/Station 312.000
PIPEFLOW TRAVEL TIME (User specified size) kk
Upstream point/station elevation = 284.98(Ft.)
Downstream point/station elevation = 282.84 (Ft.)
Pipe length = 58.27(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.340(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 1.340(CFS)
Normal flow depth in pipe = 3.15 (In.)
Flow top width inside pipe = 13.67 (In.)
Critical Depth = 5.20(In.)
Pipe flow velocity = 6.46(Ft/s)
Travel time through pipe = 0.15 mm.
Time of concentration (TC) = 16.51 mm.
++ ++++++++++++++++++++++++++++++++++++++++++.+++++++++++++++++++++++++
Process from Point/Station 403.000 to Point/Station 312.000
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 1.100(Ac.)
Runoff from this stream = 1.340(CFS)
Tine of concentration = 16.51 mm.
Rainfall intensity = 3.414(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
N. (CFS) (mm) (In/Hr)
1 83.393 15.41 3.569
2 1.340 16.51 3.414
Qmax(l) =
1.000 * 1.000 * 83.393) +
1.000 * 0.933 * 1.340) + = 84.644
Qmax(2) =
0.957 * 1.000 * 83.393) +
1.000 * 1.000 * 1.340) + = 81.110
Total of 2 streams to confluence:
Flow rates before confluence point:
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I 83.393 1.340 Maximum flow rates at confluence using above data:
84.644 81.110
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Area of streams before confluence:
35.400 1.100
Results of confluence:
Total flow rate = 84.644(CFS)
I Time of concentration = 15.410 mm.
Effective stream area after confluence = 36.500(Ac.)
I ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 312.000 to Point/Station 313.000
kk) PIPEFLOW TRAVEL TIME (User specified size) ****
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Upstream point/station elevation = 282.51 (Ft.)
Downstream point/station elevation = 268.22 (Ft.)
Pipe length = 290.95 (Ft.) Mannings N = 0.013
I No. of pipes = 1 Required pipe flow = 84.644(CFS)
Given pipe size = 24.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
I
The approximate hydraulic grade line above the pipe invert is
43.337(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 40.718(Ft.)
Minor friction loss = 16.908(Ft.) K-factor = 1.50
I PiDe flow velocity = 26.94 (Ft/s)
Travel time through pipe = 0.18 mm.
Time of concentration (TC) = 15.59 mm.
+ + + + + + + + . + + + + + + + + - + + + + + + + + + + + + + . + + + + + + + + + + + + + + + + + + + + + + + + + + + + ± + . + + + + . + +
Process from Point/Station 313.000 to Point/Station 313.000
I
**** SUBAREA FLOW ADDITION
User specified 'C value of 0.350 given for subarea
Time of concentration = 15.59 mm.
I
Rainfall intensity = 3.543(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 2.728(CFS) for 2.200(Ac.)
Total runoff = 87.372(CFS) Total area = 38.70(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.
I Process from Point/Station 313.000 to Point/Station 313.000
SUBAREA FLOW ADDITION ****
I
User specified 'C' value of 0.900 given for subarea
Time of concentration = 15.59 mm.
Rainfall intensity = 3.543(In/I-Ir) for a 100.0 year storm
Runoff coefficien- used for sub-area, Rational method,Q=KCIA, C = 0.900
I Subarea runoff = 4.464(CFS) for 1.400(Ac.)
Total runoff = 91.836(CFS) Total area = 40.10(Ac.)
I ++++++++++++++++++++++±+++++++++±++++++++++++++++++++++++++±++++++++++
Process from Poin/Station 313.000 to Point/Station 153.000 'k PIPEFLOW TRAVEL TIME (User specified size)
.10
****
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Upstream point/station elevation = 266.22 (Ft.)
Downstream point/station elevation = 265.72(Ft.)
Pipe length = 21.26 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 91.836(CFS)
Given pipe size = 24.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
22.906(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 3.502(Ft.)
Minor friction loss = 19.904(Ft.) K-factor = 1.50
Pipe flow velocity = 29.23 (Ft/s)
Travel time through pipe = 0.01 mm.
Time of concentration (TC) = 15.60 mm.
+++++++++++++++++++++++++++++++++++++++++-1-++++++++++++++++++++++++++++
Process from Point/Station 153.000 to Point/Station 154.000
kk
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 265.72 (Ft.)
Downstream point/station elevation = 264.11 (Ft.)
Pipe length = 72.32 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 91.836(CFS)
Given pipe size = 54.00 (In.)
Calculated individual pipe flow = 91.836(CFS)
Normal flow depth in pipe = 20.74(In.)
F13w top width inside pipe = 52.53(In.)
Critical Depth
= 33.71(In.)
Pipe flow velocity = 16.31 (Ft/s)
Travel time through pipe = 0.07 mm.
Time of concentration (TC) = 15.68 mm.
End of computations, total study area = 40.10 (Ac.)
11
I
I
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 2004 Version 3.2
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/29/07 -----------------------------------------------------------------------
LA COSTA TOWN SQUARE
BASIN B - EXISTING CONDITIONS
G:\ACCTS\001017\1017B.OUT
Hydrology Study Control Information **********
O'Day Consultants, San Diego, California - SIN 10125 -----------------------------------------------------------------------
Rational hydrology study storm event year is 100.0
Map data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
Adjusted 6 hour precipitation (inches) = 2.800
P6/P24 = 54.9%
San Diego hydrology manual 'C' values used
Runoff coefficients by rational method
++±++++++++++++++++++++++++++++++.++++++++++++++++++++++++++++++++++++
Process from Point/Station 200.000 to Point/Station 200.000
USER DEFINED FLOW INFORMATION AT A POINT **** PER DWG. 368-2C,
SHT. 14
User specified 'C' value of 0.800 given for subarea
Rainfall intensity (I) = 2.879 for a 100.0 year storm
User specified values are as follows:
TC = 21.50 mm. Rain intensity = 2.88(In/Hr)
Total area = 22.10(Ac.) Total runoff = 45.40(CFS)
Process from Point/Station 200.000 to Point/Station 202.000
IRREGULAR CHANNEL FLOW TRAVEL TIME kk
Estimated mean flow rate at midpoint of channel = 60.602(CFS)
Depth of flow = 1.266(Ft.), Average velocity = 7.559(Ft/s)
Irregular Channel Data
-----------------------------------------------------------------
Information entered for subchannel number 1
Point number 'X' coordinate Y' coordinate
1 0.00 2.00
2 10.00 0.00
12
3 20.00 2.00
Manning's 'N' friction factor = 0.040
-----------------------------------------------------------------
Sub-Channel flow = 60.602(CFS)
flow top width = 12.662 (Ft.)
velocity= 7.559(Ft/s)
area = 8.017(Sq.Ft)
Froude number = 1.674
Upstream point elevation = 347.000(Ft.)
Downstream point elevation = 261.000(Ft.)
Flow length = 1100.000(Ft.)
Travel time = 2.43 mm.
Time of concentration = 23.93 mm.
Depth of flow = 1.266 (Ft.)
Average velocity = 7.559(Ft/s)
Total irregular channel flow = 60.602(CFS)
Irregular channel normal depth above invert elev. = 1.266 (Ft.)
Average velocity of channel(s) = 7.559(Ft/s)
Sub-Channel No. 1 critical depth = 1.555 (Ft.)
critical flow top width = 15.547 (Ft.)
critical flow velocity= 5.015(Ft/s)
critical flow area = 12.085(Sq.Ft)
Adding area flow to channel
User specified 'C' value of 0.350 given for subarea
Rainfall intensity = 2.688(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 13.922(CFS) for 14.800(Ac.)
Total runoff = 59.322(CFS) Total area = 36.90 (Ac.)
Process from Point/Station 202.000 to Point/Station 202.000
SUBAREA FLOW ADDITION ****
User specified 'C' value of 0.350 given for subarea
Time of concentration = 23.93 mm.
Rainfall intensity = 2.688(In/Hr) for a 100.0 year storm
Runoff coefficient, used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 8.466(CFS) for 9.000(Ac.)
Total runoff = 67.788(CFS) Total area = 45.90Ac.)
Process from Point/Station 202.000 to Point/Station 202.000
SUBAREA FLOW ADDITION ****
User specified 'C value of 0.900 given for subarea
Time of concentration = 23.93 mm.
Rainfall intensity = 2.688(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.900
Subarea runoff = 5.563(CFS) for 2.300 (Ac.)
Toal runoff = 73.351(CFS) Total area = 48.20 (Ac.)
End of computations, total study area = 48.20 (Ac.)
13
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 2004 Version 3.2
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 08/29/07 -----------------------------------------------------------------------
LA COSTA TOWN SQUARE
BASIN C - EXISTING CONDITIONS
G:\ACCTS\001017\1017C.OUT
Hydrology Study Control Information
O 'Day Consultants, San Diego, California - SIN 10125
-----------------------------------------------------------------------
Rational hydrology study storm event year is 100.0
Map data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
Adjusted 6 hour precipitation (inches) = 2.800
P6/P24 = 54.9%
San Diego hydrology manual C values used
Runoff coefficients by rational method
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++±+++++++++
Process from Point/Station 300.000 to Point/Station 300.000
USER DEFINED FLOW INFORMATION AT A POINT **** PER DWG. 368-2, SHT.
User specified C value of 0.800 given for subarea
Rainfall intensity (I) = 3.350 for a 100.0 year storm
User specified values are as follows:
TC = 17.00 mm. Rain intensity = 3.35(In/Hr)
Tonal area = 10.80(Ac.) Total runoff = 32.50(CFS)
++f++++++++++++++-+++++++++++++++++++++++++++++.+f+++++++++...+++..++.
Process from Point/Station 300.000 to Point/Station 300.000
SUBAREA FLOW ADDITION ****
User specified C value of 0.350 given for subarea
Time of concentration = 17.00 mm.
Rainfall intensity = 3.350(In/Hr) for a 100.0 year storm
14
I Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 1.173(CFS) for 1.000(Acj
Total runoff = 33.673(CFS) Total area = 11.80(Ac.)
+++++++++++++++++-1-++++++++++++++++++++++++++-1-+++++++++++++++++++++++++
Process from Point/Station 300.000 to Point/Station 302.000
I IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 308.00(Ft.)
I
Downstream point elevation = 268.00(Ft.)
Channel length thru subarea = 600.00(Ft.)
Channel base width = 1.000(Ft.)
Slope or 'Z' of left channel bank = 2.000
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Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 40.664(CFS)
Manning's 'N' = 0.015
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Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 40.664(CFS)
Depth of flow = 0.900(Ft.), Average velocity = 16.143(Ft/s)
Channel flow top width = 4.599(Ft.)
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Flow Velocity = 16.14 (Ft/s)
Travel time = 0.62 mm.
Time of concentration = 17.62 mm.
Critical depth = 1.672(Ft.)
I Adding area flow to channel User specified 'C' value of 0.350 given for subarea
Rainfall intensity = 3.274(In/Hr) for a 100.0 year storm
I
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 5.615(CFS) for 4.900(Ac.)
Total runoff = 39.287(CFS) Total area = 16.70(Ac.)
I +++++++++++++++++++++++++++++++++++++++++++++++++_++++++++++++++++++++
Process from Point/Station 302.000 to Point/Station 302.000
I
SUBAREA FLOW ADDITION
User specified 'C' value of 0.350 given for subarea
Time of concentration = 17.62 mm.
I
Rainfall intensity = 3.274(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.350
Subarea runoff = 15.469(CFS) for 13.500(AcJ
Total runoff = 54.757(CFS) Total area = 30.20(Ac.)
I
End of computations, total study area = 30.20 (Ac.)
15
APPENDIX 2
100 Yr. Interim Hydrologic Calculations- Mass Grading
(See Exhibit 'J')
16
San Diego County Rational Hydrology Program
CPJILCADD/CIVILDESIGN Engineering Software, (c)1991-2004 Version 7.4
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 12/30/11 -----------------------------------------------------------------------
100 Year Storm Hydrology Calculations LCTS-Office
Pad Grading- Basin A
Calculations By: NF 12/30/2011
I: \001017\_Office\Stormwater\Drainage\1090kga.out
Hydrology Study Control Information
Program License Serial Number 5007
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
P6/P24 = 54.9%
San Diego hydrology manual C values used
++±.++++++++++++++++++++++++++++++++++++++++++++++.+++++++++++++++++++
Process from Point/Station 100.000 to Point/Station 101.000
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN I
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 65.000(Ft.)
Highest elevation = 338.000(Ft.)
Lowest elevation = 317.200(Ft.)
Elevation difference = 20.800(Ft.) Slope = 32.000 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
17
I Permanent Open Space In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.34 minutes
I
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/31]
TC = [1.8*(1.1_0.3500)*( 100.000".5)/( 30.000'(1/3)1= 4.34
Rainfall intensity (I) = 8.077(In/I-Ir) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
I Subarea runoff = 0.141(CFS)
Total initial stream area = 0.050(Ac.)
++-I-++++++++++++++++++++++++++++++++++++++++++++++{.++++++++++++++++++++
Process from Point/Station 101.000 to Point/Station 102.000
IMPROVED CHANNEL TRAVEL TIME
1 Upstream point elevation = 317.200(Ft.)
Downstream point elevation = 305.400 (Ft.)
Channel length thru subarea = 770.000 (Ft.)
I Channel base width = 0.000(Ft.)
Slope or Z' of left channel bank = 1.000
Slope or 'Z of right channel bank = 1.000
I
Estimated mean flow rate at midpoint of channel = 0.889(CFS)
Manning's 'N = 0.015
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 0.889(CFS)
I Depth of flow = 0.485(Ft.), Average velocity = 3.784(Ft/s)
Channel flow top width = 0.969 (Ft.)
Flow Velocity = 3.78(Ft/s)
I
Travel time = 3.39 mm.
Time of concentration = 7.74 mm.
Critical depth = 0.547(Ft.)
Adding area flow to channel
I Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
I [UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
I
Sub-Area C Value = 0.350
Rainfall intensity = 5.567(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.277
I Subarea runoff = 1. 398(CFS) for 0.740 (Ac.)
Total runoff = 1.539(CFS) Total area = 0.790(Ac.)
Depth of flow = 0.596(Ft.), Average velocity = 4.340(Ft/s)
Critical depth = 0.680(Ft.)
++++++++++++++++++.+++++++++++++++++++++++++++++++++++++++++++++++++++
I Prccess from Point/Station 102.000 to Point/Station 103.000
PIPEFLOW TRAVEL TIME (User specified size)
I
Upstream point/station elevation = 290.500 (Ft.)
Downstream point/station elevation = 278.220 (Ft.)
Pipe length = 103.40 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.539(CFS)
18
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 1.539(CFS)
Normal flow depth in pipe = 2.87 (In.)
Flow top width inside pipe = 10.24(In.)
Critical Depth = 6.31(In.)
Pipe flow velocity = 10.68(Ft/s)
Travel time through pipe = 0.16 mm.
Time of concentration (TC) = 7.90 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-+++++++++
Process from Point/Station 102.000 to Point/Station 103.000
CONFLUENCE OF MAIN STREAMS ****
I The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 0.790(Ac.)
Runoff from this stream = 1.539(CFS)
I Time of concentration = 7.90 mm.
Rainfall intensity = 5.493(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 104.000 to Point/Station 105.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
I Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space I Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 75.000 (Ft.)
I Highest elevation = 294.500(Ft.)
Lowest elevation = 292.000(Ft.)
Elevation difference = 2.500(Ft.) Slope = 3.333 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
I The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 3.33 %, in a development type of
Permanent Open Space
I In Accordance With Figure 3-3
Initial Area Time of Concentration = 9.04 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)}
'u
= 1 1."(I.1-0.5500)( 100.000^.5)/( 3.333''(1/3)1 = 9.04
Rainfall intensity (I) = 5.036(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0,350
Subarea runoff = 0.106(CFS)
To-:al initial stream area = 0.060(Ac.)
I
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 105.000 to Point/Station 106.000
IMPROVED CHANNEL TRAVEL TIME
I
19
I
Upstream point elevation = 291.000(Ft.)
Downstream point elevation = 288.500 (Ft.)
Channel length thru subarea = 130.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z of left channel bank = 2.000
Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 0. 652 (CFS)
Mannings 'N = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 0.652(CFS)
Depth of flow = 0.335(Ft.), Average velocity = 2.906 (Ft/s)
Channel flow top width = 1.340 (Ft.)
Flow Velocity = 2.91(Ft/s)
Travel time = 0.75 mm.
Time of concentration = 9.78 mm.
Critical depth = 0.367 (Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 4.785(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.238
Subarea runoff = 1.033(CFS) for 0.620(Ac.)
Total runoff = 1.139(CFS) Total area = 0.680(Ac.)
Depth of flow = 0.413(Ft.), Average velocity = 3.341(Ft/s)
Critical depth = 0.457(Ft.)
++++++++++++-1-+++++.+++++++++++++++++++++++++++++++++++.++++++++++++++++
Process from Point/Station 105.000 to Point/Station 106.000
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.680(Ac.)
Runoff from this stream = 1.139(CFS)
Time of concentration = 9.78 mm.
Rainfall intensity = 4.785(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 107.000 to Point/Station 108.000
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
I Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group ID = 1.000
I
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
I
i
20
I
I
I
area
I
I
Initial subarea total flow distance = 170.000(Ft.)
Highest elevation = 294.500(Ft.)
Lowest elevation = 290.100(Ft.)
Elevation difference = 4.400(Ft.) Slope = 2.588 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 2.59 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 9.83 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope(1/3)]
TC = [1.8*(1.1_0.3500)*( 100.000".5)/( 2.588"(1/3)1= 9.83
The initial area total distance of 170.00 (Ft.) entered leaves a
remaining distance of 70.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.84 minutes
for a distance of 70.00 (Ft.) and a slope of 2.59 %
with an elevation difference of 1.81(Ft.) from the end of the top
Tt = [11.9*length(Mi)s3)/(elevation change(Ftj)].385 *60(min/hr)
= 0.840 Minutes
Tt=[(11.9*0.01333)/( 1.81)1.385= 0.84
Total initial area Ti = 9.83 minutes from Figure 3-3 formula plus
0.84 minutes from the Figure 3-4 formula = 10.67 minutes
Rainfall intensity (I) = 4.524(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.174(CFS)
Total initial stream area = 0.110 (Ac.)
++++++++++++.++++++++++++++++.++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 108.000 to Point/Station 109.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 290.100 (Ft.)
Downstream point elevation = 289.000 (Ft.)
Channel length thru subarea = 110.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or Z' of left channel bank = 2.000
Slope or Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 0. 815 (CFS)
Manning's 'N = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 0.815(CFS)
Depth of flow = 0.412(Ft.), Average velocity = 2.405 (Ft/s)
Channel flow top width = 1.647 (Ft.)
Flow Velocity = 2.40 (Ft/s)
Travel time = 0.76 mm.
Time of concentration = 11.44 mm.
Critical depth = 0.400(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
21
Sub-Area C Value = 0.350
Rainfall intensity = 4.327(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0350 CA = 0.322
Subarea runoff = 1.219(CFS) for 0.810(Ac.)
Total runoff = 1.393(CFS) Total area = 0.920(Ac.)
Depth of flow = 0.503(Ft.), Average velocity = 2.749(Ft/s)
Critical depth = 0.496(Ft.)
++++++++++++++.++-++++++++++++++++++++-I-+++++++++++++++++++++++++++++++
Process from Point/Station 108.000 to Point/Station 109.000
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.920(Ac.)
Runoff from this stream = 1.393(CFS)
Time of concentration = 11.44 mm.
Rainfall intensity = 4.327(In/Hr)
Summary of stream data:
Stream Flow rate TC
No. (CFS) (mm)
1 1.139 9.78
2 1.393 11.44
Qmax(1) =
1.000 * 1.000 *
1.000 * 0.856 *
Qmax(2) =
Rainfall Intensity
(In/Hr)
4.785
4.327
1.139) +
1.393) + = 2.331
0.904 * 1.000 * 1.139) +
1.000 * 1.000 * 1.393) + = 2.423
Total of 2 streams to confluence:
Flow rates before confluence point:
1.139 1.393
Maximum flow rates at confluence using above data:
2.331 2.423
Area of streams before confluence:
0.680 0.920
Results of confluence:
Total flow rate = 2.423(CFS)
Time of concentration = 11.435 mm.
Effective stream area after confluence = 1.600 (Ac.)
+++++++++++++++++ -'-++++++++++++++++++++++++++4++++++++++++++++++++++++.
Process from Point/Station 110.000 to Point/Station 103.000
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 281.000 (Ft.)
Downstream point/station elevation = 278.220(Ft.)
Pipe length = 245.10 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 2.423(CFS)
Given pipe size = 18.00 (In.)
Calculated individual pipe flow = 2.423(CFS)
22
Normal flow depth in pipe = 5.69(In.)
Flow top width inside pipe = 16.74(In.)
Critical Depth = 7.06(In.)
Pipe flow velocity = 5.06 (Ft/s)
Travel time through pipe = 0.81 mm.
Time of concentration (TC) = 12.24 mm.
Process from Point/Station 110.000 to Point/Station 103.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.600(Ac.)
Runoff from this stream = 2.423(CFS)
Time of concentration = 12.24 mm.
Rainfall intensity = 4.140(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 1.539 7.90 5.493
2 2.423 12.24 4.140
Qmax(l) =
1.000 * 1.000 * 1.539) +
1.000 * 0.645 * 2.423) + = 3.102
Qmax(2) =
0.754 * 1.000 * 1.539) +
1.000 * 1.000 * 2.423) + = 3.583
Toa1 of 2 main streams to confluence:
Flow rates before confluence point:
1.539 2.423
Maximum flow rates at confluence using above data:
- 3.102 3.583
Area of streams before confluence:
1 0.790 1.600
Results of confluence:
Total flow rate = 3.583(CFS)
Time of concentration = 12.243 mm.
Effective stream area after confluence = 2.390(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++.++++++++++++++++
Process from Point/Station 103.000 to Point/Station 111.000
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 277.890 (Ft.)
Downstream point/station elevation = 276.650(Ft.)
Pipe length = 7.80 (Ft.) Mannings N = 0.013 Im No. of pipes = 1 Required pipe flow = 3.583(CFS)
Given pipe size = 18.00(In.)
-
23
Calculated individual pipe flow = 3.583(CFS)
Normal flow depth in pipe = 3.56(In.)
Flow top width inside pipe = 14.34(In.)
Critical Depth = 8.68(In.)
Pipe flow velocity = 14.48 (Ft/s)
Travel time through pipe = 0.01 mm.
Time of concentration (TC) = 12.25 mm.
End of computations, total study area = 2.390 (Ac.)
I
H
I
24
I
San Diego County Rational Hydrology Program
I CIVILCADD/CIVILDESIGN Engineering Software, (c)1991-2004 Version 7.4
Rational method hydrology program based on
I San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 01/04/12 -----------------------------------------------------------------------
I 100 Year Storm Hydrology Calculations LCTS-Office
Pad Grading- Basin B
Calculations By: NF I I: \001017\_Office\Stormwater\Drainage\1090kgb.out
Hydrology Study Control Information **********
Program License Serial Number 5007
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Mao data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
P6/P24 = 54.9%
San Diego hydrology manual 'C' values used
+++++++++++++++++ ±++++++++++.+++++++++++++++++++++++++++++++++++++++++
I
Process from Point/Station 104.000 to Point/Station 201.000
INITIAL AREA EVALUATION ****
I
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN I (Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
I
Initial subarea total flow distance = 85.000 (Ft.)
Highest elevation = 294.500(Ft.)
Lowest elevation = 291.300(Ft.)
Elevation difference = 3.200(Ft.) Slope = 3.765 % I Top of Initial Area Slope adjusted by User to 2.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
I
i
25
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 9.88 minutes
TC = [1.8*(1.1_C)*distance(Ftj.5)/(% slope"(1/3))
TC = [1.8*(1.1_0.3500)*( 85.000".5)/( 2.000"(1/3)1= 9.88
Rainfall intensity (I) = 4.755(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.150 (CFS)
Total initial stream area = 0.090 (Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++.++++++++++++++++++++
Process from Point/Station 201.000 to Point/Station 202.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 291.300(Ft.)
Downstream point elevation = 290.300 (Ft.)
Channel length thru subarea = 95.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z of left channel bank = 2.000
Slope or Z of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 0.666(CFS)
Mannings N = 0.020
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 0.666(CFS)
Depth of flow = 0.378(Ft.), Average velocity = 2.330(Ft/s)
Channel flow top width = 1.512 (Ft.)
Flow Velocity = 2.33(Ft/s)
Travel time = 0.68 mm.
Time of concentration = 10.56 mm.
Critical depth = 0.369 (Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN I
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 4.555(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.249
Subarea runoff = 0.982(CFS) for 0.620(Ac.)
Total runoff = 1.132(CFS) Total area = 0.710(Ac.)
Depth of flow = 0.461(Ft.), Average velocity = 2.661(Ft/s)
Critical depth = 0.457(Ft.)
Process from Point/Station 201.000 to Point/Station 202.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
26
Stream flow area = 0.710(Ac.)
Runoff from this stream = 1.132(CFS)
Time of concentration = 10.56 mm.
Rainfall intensity = 4.555(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++-f-++++++++++-f-++++++++++++++++++++
Process from Point/Station 203.000 to Point/Station 204.000
INITIAL AREA EVALUATION
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 220.000(Ft.)
Highest elevation = 298.500(Ft.)
Lowest elevation = 293.300(Ft.)
Elevation difference = 5.200(Ft.) Slope = 2.364 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 2.36 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 934 minutes
TC = [1.8*(1.1C)*distance(Ft.).5)/(% slope'(1/3)]
TC= [1.8*(1.1_0.3500)*( 85.000".5)/( 2.364(1/3)]= 9.34
The initial area total distance of 220.00 (Ft.) entered leaves a
remaining distance of 135.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.44 minutes
for a distance of 135.00 (Ft.) and a slope of 2.36 %
with an elevation difference of 3.19(Ft.) from the end of the top
Tt = [11.9*length(Mi)3)/ (elevation change(Ft.) ) ]".385 *60(min/hr)
= 1.442 Minutes
Tt=[(11.9*0.02563)/( 3.19)]'.385= 1.44
Total initial area Ti = 9.34 minutes from Figure 3-3 formula plus
1.44 minutes from the Figure 3-4 formula = 10.79 minutes
Rainfall intensity (I) = 4.493(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.283(CFS)
Total initial stream area = 0.180 (Ac.)
+++++++++++++++++-I-++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 204.000 to Point/Station 205.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 293.300 (Ft.)
Downstream point elevation = 290.630(Ft.)
Channel length thru subarea = 207.000(Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z of left channel bank = 2.000
area
27
Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 1.422(CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 1.422(CFS)
Depth of flow = 0.484(Ft.), Average velocity = 3.040(Ft/s)
Channel flow top width = 1.934(Ft.)
Flow Velocity = 3.04 (Ft/s)
Travel time = 1.13 mm.
Time of concentration = 11.92 mm.
Critical depth = 0.500(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN I
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 4.212(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.588
Subarea runoff = 2.194(CFS) for 1.500 (Ac.)
Total runoff = 2.477(CFS) Total area = 1.680(Ac.)
Depth of flow = 0.595(Ft.), Average velocity = 3.493(Ft/s)
Critical depth = 0.625(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 204.000 to Point/Station 205.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.680(Ac.)
Runoff from this stream = 2.477(CFS)
Time of concentration = 11.92 mm.
Rainfall intensity = 4.212(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 1.132 10.56 4.555
2 2.477 11.92 4.212
Qmax(l) =
1.000 * 1.000 * 1.132) +
1.000 * 0.886 * 2.477) + = 3.326
Qmax(2) =
0.925 * 1.000 * 1.132) +
1.000 * 1.000 * 2.477) + = 3.524
Total of 2 main streams to confluence:
Flow rates before confluence point:
1.132 2.477
Maximum flow rates at confluence using above data:
3.326 3.524
Area of streams before confluence:
0.710 1.680
Results of confluence:
Total flow rate = 3.524(CFS)
Time of concentration = 11.920 mm.
Effective stream area after confluence = 2.390(Ac.)
++++++++++++++++.+++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 206.000 to Point/Station 207.000
'k'kk PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 282.900 (Ft.)
Downstream point/station elevation = 279.370 (Ft.)
Pipe length = 320.80 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 3.524(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 3.524(CFS)
Normal flow depth in pipe = 7.00(In.)
Flow top width inside pipe = 17.55(In.)
Critical Depth = 8.59(In.)
Pipe flow velocity = 5.55 (Ft/s)
Travel time through pipe = 0.96 mm.
Time of concentration (TC) = 12.88 mm.
Process from Point/Station 207.000 to Point/Station 208.000
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 279.020 (Ft.)
Downstream point/station elevation = 258.500(Ft.)
Pipe length = 64.40(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 3.524(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 3.524(CFS)
Normal flow depth in pipe = 2.98(In.)
Flow top width inside pipe = 13.37(In.)
Critical Depth = 8.59(In.)
Pipe flow velocity = 18.40 (Ft/s)
Travel time through pipe = 0.06 mm.
Time of concentration (TC) = 12.94 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 207.000 to Point/Station 208.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 2.390(Ac.)
Runoff from this stream = 3.524(CFS)
Time of concentration = 12.94 mm.
29
R
Rainfall intensity = 3.995(In/Hr)
Program is now starting with Main Stream No. 2
+++++++++++++++++++++++-I-++++++++++++++++++++++++++++++++++++1.+++++++++
Process from Point/Station 105.000 to Point/Station 209.000
kk INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea tctal flow distance = 95.000(Ft.)
Highest elevation = 292.000(Ft.)
Lowest elevation = 287.400(Ft.)
Elevation difference = 4.600(Ft.) Slope = 4.842 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 4.84 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 7.98 minutes
TC = [1.8*(1.1C)*distance(Ft.).5)/(% s1ope'(1/3]
TC= [1.8*(1.1_0.3500)*( 100.000'.5)/( 4.842"(1/3)]= 7.98
Rainfall intensity (I) = 5.457(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.172(CFS)
Total initial stream area = 0.090 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++_+++++++++
Process from Point/Station 209.000 to Point/Station 210.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 287.400 (Ft.)
Downstream point elevation = 277.000 (Ft.)
Channel length thru subarea = 110.000(Ft.)
Channel base width = 0.000 (Ft.)
Slope or 'Z' of left channel bank = 2.000
Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 0.535 (CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 0.535(CFS)
Depth of flow = 0.231(Ft.), Average velocity = 5.025 (Ft/s)
Channel flow top width = 0.923 (Ft.)
Flow Velocity = 5.03 (Ft/s)
Travel time = 0.36 mm.
- Time of concentration = 8.34 mm.
Critical depth = 0.338 (Ft.)
Adding area flow to channel
User specified 'C' value of 0.350 given for subarea
Rainfall intensity = 5.302(In/Hr) for a 100.0 year storm
30
I Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.164
Subarea runoff = 0.700(CFS) for 0.380 (Ac.)
I Total runoff = 0.872(CFS) Total area = 0.470(Ac.)
Depth of flow = 0.277(Ft.), Average velocity = 5.679(Ft/s)
Critical depth = 0.410(Ft.)
I Prccess from Point/Station 209.000 to Point/Station 210.000
I CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.470 (Ac.)
I Runoff from this stream = 0.872(CFS)
Time of concentration = 8.34 mm.
Rainfall intensity = 5.302(In/Hr)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++4++++++++++++
Process from Point/Station 210.100 to Point/Station 210.200
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 57.000(Ft.)
Highest elevation = 291.600(Ft.)
Lowest elevation = 278.300(Ft.)
Elevation difference = 13.300(Ft.) Slope = 23.333 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.34 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)]
TC = [1.8*(1.1_0.3500)*( 100.000".5)/( 30.000"(1/3)1= 4.34
Rainfall intensity (I) = 8.077(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.085(CFS)
Total initial stream area = 0.030(Ac.)
Process from Point/Station 210.200 to Point/Station 210.300
IMPROVED CHANNEL TRAVEL TIME ?k
Upstream point elevation = 278.000 (Ft.)
Downstream point elevation = 272.500 (Ft.)
Channel length thru subarea = 277.000 (Ft.)
31
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Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 8.000
Slope or 'Z' of right channel bank = 8.000
Estimated mean flow rate at midpoint of channel = 0.333(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 0.170 (Ft.)
Flow(q) thru subarea = 0.333(CFS)
Depth of flow = 0.135(Ft.), Average velocity = 2.297(Ft/s)
Channel flow top width = 2.153 (Ft.)
Flow Velocity = 2.30(Ft/s)
Travel time = 2.01 mm.
Time of concentration = 6.35 mm.
Critical depth = 0.160(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 6.321(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.080
Subarea runoff = 0.424(CFS) for 0.200(Ac.)
Total runoff = 0.509(CFS) Total area = 0.230(Ac.)
Depth of flow = 0.158(Ft.), Average velocity = 2.555(Ft/s)
Critical depth = 0.188(Ft.)
Process from Point/Station 210.200 to Point/Station 210.300
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.230(Ac.)
Runoff from this stream = 0.509(CFS)
Time of concentration = 6.35 mm.
Rainfall intensity = 6.321(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 0.872 8.34 5.302
2 0.509 6.35 6.321
Qmax(l) =
1.000 * 1.000 * 0.872) +
0.839 * 1.000 * 0.509) + = 1.299
Qmax(2) =
1.000 * 0.761 * 0.872) +
1.000 * 1.000 * 0.509) + = 1.173
Total of 2 streams to confluence:
Flow rates before confluence point:
32
0.872 0.509
Maximum flow rates at confluence using above data:
1.299 1.173
Area of streams before confluence:
0.470 0.230
Results of confluence:
Total flow rate = 1.299(CFS)
Time of concentration = 8.345 mm.
Effective stream area after confluence = 0.700(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++f++++++++
Process from Point/Station 210.000 to Point/Station 211.000
PIPEFLOW TRAVEL TIME (User specified size) kk
Upstream point/station elevation = 266.500(Ft.)
Downstream point/station elevation = 265.900 (Ft.)
Pipe length = 80.50(Ft.) Mannings N = 0.013
No. of pipes = 1 Required pipe flow = 1.299(CFS)
Given pipe size = 12.00(In.)
Calculated individual pipe flow = 1.299(CFS)
Normal flow depth in pipe = 5.44(In.)
Flow top width inside pipe = 11.95(In.)
Critical Depth = 5.78(In.)
Pipe flow velocity = 3.75(Ft/s)
Travel time through pipe = 0.36 mm.
Time of concentration (TC) = 8.70 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 211.000 to Point/Station 212.000
IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 265.900 (Ft.)
Downstream point elevation = 262.400 (Ft.)
Channel length thru subarea = 230.000 (Ft.)
Channel base width = 6.000 (Ft.)
Slope or Z of left channel bank = 2.000
Slope or Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 1.619 (CFS)
Mannings N = 0.035
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 1.619(CFS)
Depth of flow = 0.167(Ft.), Average velocity = 1.526 (Ft/s)
Channel flow top width = 6.670(Ft.)
Flow Velocity = 1.53 (Ft/s)
Travel time = 2.51 mm.
Time of concentration = 11.21 mm.
Critical depth = 0.129(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
33
Sub-Area C Value = 0.350
RaLnfall intensity = 4.381(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.430
Subarea runoff = 0.587 (CFS) for 0.530 (Ac.)
Total runoff = I 1.886(CFS) Total area = 1.230(Ac.)
Depth of flow = 0.183(Ft.), Average velocity = 1.615(Ft/s)
Crtical depth = 0.143(Ft.)
+ + - + + + + + + + + + +,+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Process from Point/Station 212.000 to Point/Station 208.000
PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 259.400 (Ft.)
Downstream point/station elevation = 258.500(Ft.)
Pipe length = 167.30 (Ft.) Manning's N = 0.013
No.. of pipes = 1 Required pipe flow = 1.886(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 1.886(CFS)
Normal flow depth in pipe = 6.06(In.)
Flow top width inside pipe = 17.02 (In.)
Critical Depth = 6.20(In.)
Pipe flow velocity. = 3.60 (Ft/s)
Travel time through pipe = 0.77 mm.
Time of concentration (TC) = 11.99 mm.
++-+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 212.000 to Point/Station 208.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.230 (Ac.)
Runoff from this stream = 1.886(CFS)
Time of concentration = 11.99 mm.
Rainfall intensity = 4.197(In/Hr)
Summary of stream data:
Stream Flow rate TC
No. (CFS) (mm)
1 3.524 12.94
2 1.886 11.99
Qmax(l) =
1.000 * 1.000 *
0.952 * 1.000 *
Qmax (2)
Rainfall Intensity
(In/Hr)
3.995
4.197
3.524) +
1.886) + = 5.319
1.000 * 0.926 * 3.524) +
1.000 * 1.000 * 1.886) + = 5.150
Total of 2 main streams to confluence:
Flow rates before confluence point:
3.524 1.886
Maximum flow rates at confluence using above data:
34
I
5.319 5.150
Area of streams before confluence:
2.390 1.230
Results of confluence:
Total flow rate = 5.319(CFS)
Time of concentration = 12.943 mm.
Effective stream area after confluence = 3.620(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 208.000 to Point/Station 213.000
PIPEFLOW TRAVEL TIME (User specified size) "''
Upstream point/station elevation = 258.500(Ft.)
Downstream point/station elevation = 257.500 (Ft.)
Pipe length = 95.80 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 5.319(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 5.319(CFS)
Normal flow depth in pipe = 8.95(In.)
Flow top width inside pipe = 18.00(In.)
Critical Depth = 10.66(In.)
Pipe flow velocity = 6.06 (Ft/s)
Travel time through pipe = 0.26 mm.
Time of concentration (TC) = 13.21 mm.
+++ ...................................................................
Process from Point/Station 213.000 to Point/Station 213.000
SUBAREA FLOW ADDITION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Time of concentration = 13.21 mm.
Rainfall intensity = 3.943(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 1.365
Subarea runoff = 0.063(CFS) for 0.280 (Ac.)
Total runoff = 5.382(CFS) Total area = 3.900(Ac.)
End of computations, total study area = 3.900 (Ac.)
I
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35
APPENDIX 3
100 Yr. Ultimate Hydrologic Calculations
(General Commercial C Value)
(See Exhibit 'K')
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36
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c)1991-2004 Version 7.4
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 12/30/11
-----------------------------------------------------------------------
100 Year Storm Hydrology Calculations LCTS-Office
Ultimate Conditions- Basin A (General Commercial C Value)
Calculations By: NF 12/30/2011
I:\001017\—Office\Stormwater\Drainage\1090kua.out
-----------------------------------------------------------------------
Hydrology Study Control Information
Program License Serial Number 5007
Raional hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
P6/P24 = 54.9%
San Diego hydrology manual 'C' values used
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-1++++++++
Process from Point/Station 100.000 to Point/Station 101.000
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimalfraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 65.000 (Ft.)
Highest elevation = 338.000(Ft.)
Lowest elevation = 317.200(Ft.)
Elevation difference = 20.800(Ft.) Slope = 32.000 %
L
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Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.34 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% s1ope(1/3)]
TC = [1.8*(l.1_0.3500)*( 100.000".5)/( 30.000"(1/3)1= 4.34
Rainfall intensity (I) = 8.077(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.141(CFS)
Total initial stream area = 0.050(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++1+++
Process from Point/Station 101.000 to Point/Station 102.000
**** IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 317.200 (Ft.)
Downstream point elevation = 305.400 (Ft.)
Channel length thru subarea = 770.000(Ft.)
Channel base width = 0.000 (Ft.)
Slope or 'Z of left channel bank = 1.000
Slope or Z' of right channel bank = 1.000
Estimated mean flow rate at midpoint of channel = 0.889(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 0.889(CFS)
Depth of flow = 0.485(Ft.), Average velocity = 3.784(Ft/s)
Channel flow top width = 0.969 (Ft.)
Flow Velocity = 3.78(Ft/s)
Travel time = 3.39 mm.
Time of concentration = 7.74 mm.
Critical depth = 0.547(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN I
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 5.567(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.277
Subarea runoff = 1.398(CFS) for 0.740(Ac.)
Total runoff = 1.539(CFS) Total area = 0.790(Ac.)
Depth of flow = D.596(Ft.), Average velocity = 4.340(Ft/s)
Critical depth = 0.680(Ft.)
Prccess from Point/Station 102.000 to Point/Station 103.000
PIPEFLOW TRAVEL TIME (User specified size) kk
IN
Upstream point/station elevation = 290.500(Ft.)
Downstream point/station elevation = 278.220(Ft.)
Pipe length = 103.40 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.539(CFS)
Given pipe size = 12.00 (In.)
Calculated individual pipe flow = 1.539(CFS)
Normal flow depth in pipe = 2.87(In.)
Flow top width inside pipe = 10.24(In.)
Critical Depth = 6.31(In.)
Pipe flow velocity = 10.68(Ft/s)
Travel time through pipe = 0.16 mm.
Time of concentration (TC) = 7.90 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 102.000 to Point/Station 103.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 0.790 (Ac.)
Runoff from this stream = 1.539(CFS)
Time of concentration = 7.90 mm.
Rainfall intensity = 5.493 (In/Br)
Program is now starting with Main Stream No. 2
Process from Point/Station 104.000 to Point/Station 105.000
k INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Initial subarea total flow distance = 75.000 (Ft.)
Highest elevation = 294.500(Ft.)
Lowest elevation = 292.000(Ft.)
Elevation difference = 2.500(Ft.) Slope = 3.333 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 3.33 %, in a development type of
General Commercial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.11 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope'(1/3)]
TC = [1.8*(1.1_0.8200)*( 85.000".5)/( 3.333"(1/3)]= 3.11
Rainfall intensity (I) = 10.019(In/I-Ir) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.820
Subarea runoff = 0.493(CFS)
Total initial stream area = 0.060 (Ac.)
ow
39
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 105.000 to Point/Station 106.000
IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 291.000(Ft.)
Downstream point elevation = 288.500(Ft.)
Channel length thru subarea = 130.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank 2.000
Slope or 'Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 2.810CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 2.810(CFS)
Depth of flow = 0.579(Ft.), Average velocity = 4.187(Ft/s)
Channel flow top width = 2.317 (Ft.)
Flow Velocity = 4.19 (Ft/s)
Travel time = 0.52 mm.
Time of concentration = 3.63 mm.
Critical depth = 0.656(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Rainfall intensity = 9.073(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.820 CA = 0.558
Subarea runoff = 4.566(CFS) for 0.620(Ac.)
Total runoff = 5.059(CFS) Total area = 0.680(Ac.)
Depth of flow = 0.722(Ft.), Average velocity = 4.850(Ft/s)
Critical depth = 0.832(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 105.000 to Point/Station 106.000
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.680 (Ac.)
Runoff from this stream = 5.059(CFS)
Time of concentra-ion = 3.63 mm.
Rainfall intensity = 9.073(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.+++
Process from Poin/Station 107.000 to Point/Station 108.000
kk INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
Im
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(COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Initial subarea total flow distance = 170.000(Ft.)
Highest elevation = 294.500(Ft.)
Lowest elevation = 290.100(Ft.)
Elevation difference = 4.400(Ft.) Slope = 2.588 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 2.59 %, in a development type of
General Commercial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.38 minutes
TIC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope'(1/3)]
TC= [l.8*(1.1_0.8200)*( 85.000".5)/( 2.588"(1/3)1= 3.38
The initial area total distance of 170.00 (Ft.) entered leaves a
remaining distance of 85.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 0.98 minutes
for a distance of 85.00 (Ft.) and a slope of 2.59 %
with an elevation difference of 2.20(Ft.) from the end of the top
Tt =[11.9 *length (Mi )^3 )/(elevation change(Ft.) ) ].385 *60(mjn/hr)
= 0.976 Minutes
Tt=[(11.9*0.0161s3)/( 2.20)]".385= 0.98
Total initial area Ti = 3.38 minutes from Figure 3-3 formula plus
0.98 minutes frcm the Figure 3-4 formula = 4.36 minutes
Rainfall intensity (I) = 8.059(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.820
Subarea runoff = 0.727(CFS)
Total initial stream area = 0.110(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++-I-++++++++++++++++++++++++
Process from Point/Station 108.000 to Point/Station 109.000
IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 290.100 (Ft.)
Downstream point elevation = 289.000 (Ft.)
Channel length thru subarea = 110.000 (Ft.)
Channel base width = 0.000 (Ft.)
Slope or 'Z of left channel bank = 2.000
Slope or Z of right channel bank = 2.000
Esimated mean flow rate at midpoint of channel = 3.131(CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 3.131(CFS)
Depth of flow = 0.682(Ft.), Average velocity = 3.366(Ft/s)
Channel flow top width = 2.728 (Ft.)
Flow Velocity = 3.37(Ft/s)
Travel time = 0.54 mm.
Time of concentration = 4.90 mm.
Critical depth = 0.688(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
41
area
Decimal fraction soil group D = 1.000
[COMMERCIAL area type I
(Neighborhod Commercial
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Rainfall intensity = 7.469(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.794 CA = 0.730
Subarea runoff = 4.727(CFS) for 0.810(Ac.)
Total runoff = 5.453(CFS) Total area = 0.920(Ac.)
Depth of flow = D.840(Ft.), Average velocity = 3.867(Ft/s)
Critical depth = 0.859(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 108.000 to Point/Station 109.000
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.920(Ac.)
Runoff from this stream = 5.453(CFS)
Time of concentration = 4.90 mm.
Rainfall intensity = 7.469(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 5.059 3.63 9.073
2 5.453 4.90 7.469
Qmax(l) =
1.000 * 1.000 * 5.059) +
1.000 * 0.740 * 5•453) + = 9.093
Qmax(2) =
0.823 * 1.000 * 5.059) +
1.000 * 1.000 * 5.453) + = 9.618
Total of 2 streams to confluence:
Flow rates before confluence point:
5.059 5.453
Maximum flow rates at confluence using above data:
9.093 9.618
Area of streams before confluence:
0.680 0.920
Results of confluence:
To-:al flow rate = 9.618(CFS)
Time of concentration = 4.905 mm.
Effective stream area after confluence = 1.600(Ac.)
++++++++++++++++++++++++.+++++++++++++++++++++++++++++++++.+++++++++++
Process from Point/Station 110.000 to Point/Station 103.000
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 281.000 (Ft.)
Downstream point/station elevation = 278.220 (Ft.)
42
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Pipe length = 245.10(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 9.618(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 9.618(CFS)
Normal flow depth in pipe = 12.87(In.)
Flow top width inside pipe = 16.25(In.)
Critical Depth = 14.36(In.)
Pipe flow velocity = 7.12 (Ft/s)
Travel time through pipe = 0.57 mm.
Time of concentration (TC) = 5.48 mm.
+++++++++++++.+++++++++++++++++++++++++++++++++++++++++++++++f++++++++
Process from Point/Station 110.000 to Point/Station 103.000 **** CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.600 (Ac.)
Runoff from this stream = 9.618(CFS)
Time of concentration = 5.48 mm.
Rainfall intensity = 6.955(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 1.539 7.90 5.493
2 9.618 5.48 6.955
Qmax(l) =
1.000 * 1.000 * 1.539) +
0.790.* 1.000 * 9.618) + = 9.136
Qmax(2) =
1.000 * 0.694 * 1.539) +
1.000 * 1.000 * 9.618) + = 10.686
Total of 2 main streams to confluence:
Flow rates before confluence point:
1.539 9.618
Maximum flow rates at confluence using above data:
9.136 10.686
Area of streams before confluence:
0.790 1.600
Results of confluence:
Total flow rate = 10.686(CFS)
Time of concentration = 5.478 mm.
Effective stream area after confluence = 2.390(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Prccess from Point/Station 103.000 to Point/Station 111.000
PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 277.890(Ft.)
43
Downstream point/station elevation = 276.650(Ft.)
Pipe length = 7.80 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 10.686(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 10.686(CFS)
Normal flow depth in pipe = 6.20(In.)
Flow top width inside pipe = 17.11(In.)
Critical Depth = 15.06(In.)
Pipe flow velocity = 19.81(Ft/s)
Travel time through pipe = 0.01 mm.
Time of concentration (TC) = 5.48 mm.
End of computations, total study area = 2.390 (Ac.)
I
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IM
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (C) 1991-2004 Version 7.4
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 01/04/12 -----------------------------------------------------------------------
100 Year Storm Hydrology Calculations LCTS-Office
Ultimate Conditions- Basin B (Commercial C Value)
Caculãtions By: NF
I: \001017\Office\Stormwater\Drainage\1090kub.out -----------------------------------------------------------------------
Hydrology Study Control Information
-----------------------------------------------------------------------
Program License Serial Number 5007
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.800
24 hour precipitation(inches) = 5.100
P6./P24 = 54.9%
San Diego hydrology manual C values used
++++++-l-+++++++++++++++++++++++++++++++++++++++++++++++++++++++4+++++++
Process from Point/Station 104.000 to Point/Station 201.000
**k* INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
ImDervious value, Ai = 0.850
Sub-Area C Value = 0.820
Initial subarea total flow distance = 85.000 (Ft.)
Highest elevation = 294.500(Ft.)
I Lowest elevation = 291.300(Ft.)
Elevation difference = 3.200(Ft.) Slope = 3.765 %
Top of Initial Area Slope adjusted by User to 2.000 %
45
I
I
I
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 75.00 (Ft)
for the top area slope value of 2.00 %, in a development type of
General Commercial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.46 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)]
TC = Li. L.I-U.2UU)'( /5.000".5)/( 2.000(1/3)1= 3.46
Rainfall intensity (I) = 9.347(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.820
Subarea runoff = 0.690(CFS)
Total initial stream area = 0.090(Ac.)
Process from Point/Station 201.000 to Point/Station 202.000
IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 291.300 (Ft.)
Downstream point elevation = 290.300 (Ft.)
Channel length thru subarea = 95.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or Z of left channel bank = 2.000
Slope or 'Z of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 2.808(CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 2.808(CFS)
Depth of flow = 0.648(Ft.), Average velocity = 3.340(Ft/s)
Channel flow top width = 2.594(Ft.)
Flow Velocity = 3.34(Ft/s)
Travel time = 0.47 mm.
Time of concentration = 3.94 mm.
Critical depth = 0.656(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(Neighborhod Commercial
Impervious value, Ai = 0.800
Sub-Area C Value = 0.790
Rainfall intensity = 8.605(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.794 CA = 0.564
Subarea runoff = 4.160(CFS) for 0.620(Ac.)
Total runoff = 4.850(CFS) Total area = 0.710(Ac.)
Depth of flow = 0.796(Ft.), Average velocity = 3.828(Ft/s)
Critical depth = 0.820(Ft.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 201.000 to Point/Station 202.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
I
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I
In Main Stream number: 1
Stream flow area = 0.710(Ac.)
Runoff from this stream = 4.850(CFS)
Time of concentration = 3.94 mm.
Rainfall intensity = 8.605(In/Hr)
Program is now starting with Main Stream No. 2
+++++++++++++++++-+++++++++++++++++++++++++++++++++++++++++(++++++++++
Process from Point/Station 203.000 to Point/Station 204.000
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Initial subarea total flow distance = 220.000(Ft.)
Highest elevation = 298.500(Ft.)
Lowest elevation = 293.300(Ft.)
Elevation difference = 5.200(Ft.) Slope = 2.364 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 75.00 (Ft)
for the top area slope value of 2.36 %, in a development type of
General Commercial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.28 minutes
TC = [1.8* (1.1-C) "distance(Ft.) .5) / (% slope" (1/3)]
TC = [1.8*(1.1_0.8200)*( 75.000".5)/( 2.364"(1/3)1= 3.23
The initial area total distance of 220.00 (Ft.) entered leaves a
remaining distance of 145.00 (Ft.)
Using Figure 3-4, the travel time for this distance is 1.52 minutes
for a distance of 145.00 (Ft.) and a slope of 2.36 %
with an elevation difference of 3.43(Ft.) from the end of the top
area
Tt = (11.9*lengthMi)3)/(elevation change(Ft.))]".385 *60(min/hr)
= 1.524 Minutes
Tt=[ (ll.9*0.02753)/( 3.43)1'.385= 1.52
Total initial area Ti = 3.28 minutes from Figure 3-3 formula plus
1.52 minutes from the Figure 3-4 formula = 4.80 minutes
Rainfall intensity (I) = 7.574(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.820
Subarea runoff = 1.118(CFS)
Total initial stream area = 0.180 (Ac.)
+++++++++++++++++_+++++++++++++++++++++++++++++++++++++++++++++++++.++
Process from Point/Station 204.000 to Point/Station 205.000
kk IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 293.300 (Ft.)
Downstream point elevation = 290.630 (Ft.)
- Channel length thru subarea = 207.000 (Ft.)
Channel base width = 0.000 (Ft.)
47
Slope or 'Z' of left channel bank = 2.000
Slope or Z' of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 5.306(CFS)
Manning's 'N' = 0.020
Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 5.306(CFS)
Depth of flow = 0.792(Ft.), Average velocity = 4.226(Ft/s)
Channel flow top width = 3.170(Ft.)
Flow Velocity = 4.23 (Ft/s)
Travel time = 0.82 mm.
Time of concentration = 5.62 mm.
Critical depth = 0.848(Ft.)
Addirg area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Rainfall intensity = 6.844(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.820 CA = 1.378
Subarea runoff = 8.310(CFS) for 1.500(Ac.)
Total runoff = 9.428(CFS) Total area = 1.680(Ac.)
Depth of flow = 0.983(Ft.), Average velocity = 4.879(Ft/s)
Critical depth = 1.055(Ft.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++1++++++++++++++++
Process from Point/Station 204.000 to Point/Station 205.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.680(Ac.)
Runoff from this stream = 9.428(CFS)
Time of concentration = 5.62 mm.
Rainfall intensity = 6.844(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 4.850 3.94 8.605
2 9.428 5.62 6.844
Qmax(l) =
1.000 * 1.000 * 4.850) +
1.000 * 0.701 * 9.428) + = 11.460
Qmax(2) =
0.795 * 1.000 * 4.850) +
1.000 * 1.000 * 9.428) + = 13.285
Total of 2 main streams to confluence:
Flow rates before confluence point:
EM
4.850 9.428
Maximum flow rates at confluence using above data:
11.460 13.285
Area of streams before confluence:
0.710 1.680
Results of confluence:
Total flow rate = 13.285(CFS)
Time of concentration = 5.617 mm.
Effective stream area after confluence = 2.390 (Ac.)
++++++++++++++++++++++++.++++++++++++++++++++++-+++++++++++++++++++++++
Process from Point/Station 206.000 to Point/Station 207.000
PIPEFLOW TRAVEL TIME (User specified size) kk
Upstream point/station elevation = 282.900(Ft.) -
Downstream point/station elevation = 279.370(Ft.)
Pipe length = 320.80(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 13.285(CFS)
Given pipe size = 18.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
2.916(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 5.130(Ft.)
Minor friction loss = 1.316(Ft.) K-factor = 1.50
Pipe flow velocity = 7.52(Ft/s)
Travel time through pipe = 0.71 mm.
Time of concentration (TC) = 6.33 mm.
+++++++++++++++++l++++++++++++++++++++++++++1+++++++++++++++++++++++++
Process from Point/Station 207.000 to Point/Station 208.000 " PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 279.020(Ft.)
Downstream point/station elevation = 258.500 (Ft.)
Pipe length = 64.40 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 13.285(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 13.285(CFS)
Normal flow depth in pipe = 5.79(In.)
Flow top width inside pipe = 16.82 (In.)
Critical Depth = 16.33(In.)
Pipe flow velocity = 27.05(Ft/s)
Travel time through pipe = 0.04 mm.
Time of concentration (TC) = 6.37 mm.
+++++++++++++++++-++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 207.000 to Point/Station 208.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 2.390 (Ac.)
Runoff from this stream = 13.285(CFS)
Time of concentration = 6.37 mm.
Rainfall intensity = 6.312(In/Hr)
Program is now starting with Main Stream No. 2
Process from Point/Station 105.000 to Point/Station 209.000
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0.820
Initial subarea total flow distance = 95.000 (Ft.)
Highest elevation = 292.000(Ft.)
Lowest elevation = 287.400(Ft.)
Elevation difference = 4.600(Ft.) Slope = 4.842 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 90.00 (Ft)
for the top area slope value of 4.84 %, in a development type of
General Commercial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 2.83 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope' (l/3)]
TC= [1.8*(1.1_0.8200)*( 90.000".5)/( 4.842'(1/3)1= 2.83
Rainfall intensity (I) = 10.659(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.820
Subarea runoff = 0.787(CFS)
Total initial stream area = 0.090 (Ac.)
++++++++++++++++++++++++++++++++++-f+++++++++++++++++++++++++++++++++++
Process from Point/Station 209.000 to Point/Station 210.000
*k IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 287.400 (Ft.)
Downstream point elevation = 277.000 (Ft.)
Channel length thru subarea = 110.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z of left channel bank = 2.000
Slope or 'Z' of right channel bank = 2.000
Estimated mean flcw rate at midpoint of channel = 2 .365 (CFS)
Manning's 'N = 0.020
Maximum depth of channel = 1.000(Ft.)
Flow(q) thru subarea = 2.365(CFS)
Depth of flow = 0.403(Ft.), Average velocity = 7.287 (Ft/s)
Channel flow top width = 1.611 (Ft.)
Flow Velocity = 7.29(Ft/s)
Travel time = 0.25 mm.
Time of concentration = 3.08 mm.
- Critical depth = 0.613(Ft.)
Adding area flow to channel
50
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[COMMERCIAL area type
(General Commercial
Impervious value, Ai = 0.850
Sub-Area C Value = 0:820
Rainfall intensity = 10.088(In/Hr) for a 100.0
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.820 CA = 0.385
Subarea runoff = 3.101(CFS) for 0.380 (Ac.)
Total runoff = 3.888(CFS) Total area =
Depth of flow = 0.485(Ft.), Average velocity = 8
Critical depth = 0.750(Ft.)
year storm
0 .470 (Ac.
252 (Ft/s)
+++++++++++++++++-f++++++++++++++++++++++++++++++++++++++++++.+++++++++
Process from Point/Station 209.000 to Point/Station 210.000
CONFLUENCE OF MINOR STREAMS
Along Main Stream number: 2 in normal stream number 1
Stream flow area = 0.470 (Ac.)
Runoff from this stream = 3.888(CFS)
Time of concentration = 3.08 mm.
Rainfall intensity = 10.088(In/Hr)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++4+++++++++++
Process from Point/Station 210.100 to Point/Station 210.200
INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
- Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
I [UNDISTURBED NATURAL TERRAIN I
(Permanent Open Space
Impervious value, Ai = 0.000
I
Sub-Area C Value = 0.350
Initial subarea total flow distance = 57.000(Ft.)
Highest elevation = 291.600(Ft.)
Lowest elevation = 278.300(Ft.)
I Elevation difference = 13.300(Ft.) Slope = 23.333 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
I for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
I
Initial Area Time of Concentration = 4.34 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)]
TC = [1.8*(1.1_0.3500)*( 100.000".5)/( 30.000"(1/3)1= 4.34
Rainfall intensity (I) = 8.077(In/Hr) for a 100.0 year storm
I Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.085(CFS)
Total initial stream area = 0.030 (Ac.)
1
51
I
+++++++.+++++++++++++++++++++++++++++++++++++++++++++++++++++±++++++++
Process from Point/Station 210.200 to Point/Station 210.300 1kk IMPROVED CHANNEL TRAVEL TIME
Upstream point elevation = 278.000 (Ft.)
Downstream point elevation = 272.500(Ft.)
Channel length thru subarea = 277.000 (Ft.)
Channel base width = 0.000 (Ft.)
Slope or 'Z of left channel bank = 8.000
Slope or 'Z of right channel bank = 8.000
Estimated mean flow rate at midpoint of channel = 0.333 (CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 0.170 (Ft.)
Flow(q) thru subarea = 0.333(CFS)
Depth of flow = 0.135(Ft.), Average velocity = 2 297 (Ft/s)
Channel flow top width = 2.153 (Ft.)
Flow Velocity = 2.30(Ft/s)
Travel time = 2.01 mm.
Time of concentration = 6.35 mm.
Critical depth = 0.160(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 6.321(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.080
Subarea runoff = 0.424(CFS) for 0.200(Ac.)
Total runoff = 0.509(CFS) Total area = 0.230(Ac.)
Depth of flow = 0.158(Ft.), Average velocity = 2.555(Ft/s)
Critical depth = 0.188(Ft.)
+++++++++++++-f-++++++-1+++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 210.200 to Point/Station 210.300
CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 2 in normal stream number 2
Stream flow area = 0.230 (Ac.)
Runoff from this stream = 0.509(CFS)
Time of concentration = 6.35 mm.
Rainfall intensity = 6.321(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 3.888 3.08 10.088
2 0.509 6.35 6.321
52
Qmax(l) = I 1.000 * 1.000 * 3.888) +
1.000 * 0.484 * 0.509) + = 4.134
Qmax(2) =
I 0.627 * 1.000 * 3.888) +
1.000 * 1.000 * 0.509) + = 2.945
Total of 2 streams to confluence:
I Flow rates before confluence point:
3.888 0.509
Maximum flow rates at confluence using above data:
I 4.134 2.945
Area of streams before confluence:
0.470 0.230
Results of confluence:
I Total flow rate = 4.134(CFS)
Time of concentration = 3.078 mm.
I
Effective stream area after confluence = 0.700 (Ac.)
Process from Point/Station 210.000 to Point/Station 211.000
I kk PIPEFLOW TRAVEL TIME (User specified size) k)k
Upstream point/station elevation = 266.500 (Ft.)
Downstream point/station elevation = 265.900(Ft.) I Pipe length = 80.50(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 4.134(CFS)
Given pipe size = 12.00(In.)
I NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
1.129(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 1.084(Ft.)
I Minor friction loss = 0.645(Ft.) K-factor = 1.50
Pipe flow velocity = 5.26(Ft/s)
Travel time through pipe = 0.25 mm.
Time of concentration (TC) = 3.33 mm.
++++++++++++++++++++++++++++++++++++.+++++++++++++++++++++++++++++++++
I Process from Point/Station 211.000 to Point/Station 212.000
IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 265.900 (Ft.) I Downstream point elevation = 262.400 (Ft.)
Channel length thru subarea = 230.000 (Ft.)
I
Channel base width = 6.000(Ft.)
Slope or 'Z' of left channel bank = 2.000
Slope or 'Z of right channel bank = 2.000
Estimated mean flow rate at midpoint of channel = 4.496(CFS)
Manning's 'N' = 0.035
I Maximum depth of channel = 1.000 (Ft.)
Flow(q) thru subarea = 4.496(CFS)
Depth of flow = 0.307(Ft.), Average velocity = 2.216(Ft/s)
I Channel flow top width = 7.227 (Ft.)
Flow Velocity = 2.22(Ft/s)
Travel time = 1.73 mm.
1
I
53
Time of concentration = 5.06 mm.
Critical depth = 0.252(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group 3 = 0.000
- Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 7.318(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.530 CA = 0.651
Subarea runoff = 0.633(CFS) for 0.530 (Ac.)
Total runoff = 4.767(CFS) Total area = 1.230(Ac.)
Depth of flow = 0.318(Ft.), Average velocity = 2.263(Ft/s)
Critical depth = 0.262(Ft.)
+++++++++++++++++++++++++++++++++++++++++++-l-++++++++++++++++++++++++++
Process from Point/Station 212.000 to Point/Station 208.000 kkk PIPEFLOW TRAVEL TIME (User specified size)
Upstream point/station elevation = 259.400 (Ft.)
Downstream point/station elevation = 258.500(Ft.)
Pipe length = 167.30(Ft.) Mannings N = 0.013
No. of pipes = 1 Required pipe flow = 4.767(CFS)
Given pipe size = 18.00(In.)
Calculated individual pipe flow = 4.767(CFS)
Normal flow depth in pipe = 10.24(In.)
Flow top width inside pipe = 17.83 (In.)
Critical Depth = 10.07(In.)
Pipe flow velocity = 4.59(Ft/s)
Travel time through pipe = 0.61 mm.
Time of concentration (TC) = 5.67 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 212.000 to Point/Station 208.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 1.230 (Ac.)
- Runoff from this stream = 4.767(CFS)
Time of concentration = 5.67 mm.
I Rainfall intensity = 6.802(In/Hr)
Summary of stream data:
I
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
I i 13.285 6.37 6.312
2 4.767 5.67 6.802
Qmax(l) =
I 54
I
I 1.000 * 1.000 * 13.285) +
0.928 * 1.000 * 4.767) + = 17.709
Qmax(2) =
1 .000 * 0.890 * 13.285) + I 1.000 * 1.000 * 4.767) + = 16.597
Total of 2 main streams to confluence:
I Flow rates before confluence point:
13.285 4.767
Maximum flow rates at confluence using above data:
17.709 16.597
I Area of streams before confluence:
2.390 1.230
Results of confluence:
Total flow rate = 17.709(CFS)
Time of concentration = 6.368 mm.
Effective stream area after confluence = 3.620(Ac.)
I ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 208.000 to Point/Station 213.000
PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 258.500(Ft.) I Downstream point/station elevation = 257.500 (Ft.)
Pipe length = 95.80 (Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 17.709(CFS) I Given pipe size = 18.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
4.061(Ft.) at the headworks or inlet of the pipe(s) I Pipe friction loss = 2.722(Ft.)
Minor friction loss = 2.339(Ft.) K-factor = 1.50
Pipe flow velocity = 10.02 (Ft/s)
Travel time through pipe = 0.16 mm. I Time of concentration (TC) = 6.53 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 208.000 to Point/Station 213.000
CONFLUENCE OF MAIN STREAMS
The following data inside Main Stream is listed:
In Main Stream number: 1
Stream flow area = 3.620 (Ac.)
Runoff from this stream = 17.709(CFS)
Time of concentration = 6.53 mm.
Rainfall intensity = 6.212(In/Hr)
Program is now starting with Main Stream No. 2
++++++++++++++++++++++++++++++++++++++++++++++.+++++++++++++++++++++++
Process from Point/Station 214.000 to Point/Station 215.000
INITIAL AREA EVALUATION ****
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Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Initial subarea total flow distance = 70.000 (Ft.)
Highest elevation = 293.200(Ft.)
Lowest elevation = 270.500(Ft.)
Elevation difference = 22.700(Ft.) Slope = 32.429 %
Top of Initial Area Slope adjusted by User to 30.000 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 100.00 (Ft)
for the top area slope value of 30.00 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 4.34 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope'(1/3)]
TC = 100.000".5)/( 30.000(1/3)1= 4.34
Rainfall intensity (I) = 8.077(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.350
Subarea runoff = 0.170(CFS)
Total initial stream area = 0.060 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.+++
Process from Point/Station 215.000 to Point/Station 213.000
kk IMPROVED CHANNEL TRAVEL TIME ****
Upstream point elevation = 270.500 (Ft.)
Downstream point elevation = 261.100 (Ft.)
Channel length thru subarea = 200.000 (Ft.)
Channel base width = 0.000(Ft.)
Slope or 'Z' of left channel bank = 8.000
Slope or 'Z' of right channel bank = 8.000
Estimated mean flow rate at midpoint of channel = 0.481(CFS)
Manning's 'N' = 0.015
Maximum depth of channel = 0.170 (Ft.)
Flow(q) thru subarea = 0.481(CFS)
Depth of flow = 0.131(Ft.), Average velocity = 3.479(Ft/s)
Channel flow top width = 2.102 (Ft.)
Flow Velocity = 3.48 (Ft/s)
Travel time = 0.96 mm.
Time of concentration = 5.30 mm.
Critical depth = 0.184(Ft.)
Adding area flow to channel
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 0.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 1.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space
Impervious value, Ai = 0.000
Sub-Area C Value = 0.350
Rainfall intensity = 7.103(In/Hr) for a 100.0 year storm
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Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.350 CA = 0.098
Subarea runoff = 0.526(CFS) for 0.220(Ac.)
Total runoff = 0.696(CFS) Total area = 0.280 (Ac.)
Depth of flow = 0.151(Ft.), Average velocity = 3.817(Ft/s)
Critical depth = 0.211(Ft.)
++++++++++++++++++ --+++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 215.000 to Point/Station 213.000
CONFLUENCE OF MAIN STREAMS ****
The following data inside Main Stream is listed:
In Main Stream number: 2
Stream flow area = 0.280 (Ac.)
Runoff from this stream = 0.696(CFS)
Time of concentration = 5.30 mm.
Rainfall intensity = 7.103(In/Hr)
Surrmary of stream data:
Stream Flow rate TC Rainfall Intensity
Nc. (CFS) (mm) (In/Fr)
1 17.709 6.53 6.212
2 0.696 5.30 7.103
Qmax(l) =
1.000 * 1.000 * 17.709) +
0.875 * 1.000 * 0.696) + = 18.317
Qmax(2) =
1.000 * 0.812 * 17.709) +
1.000 * 1.000 * 0.696) + = 15.083
Total of 2 main streams to confluence:
Flow rates before confluence point:
17.709 0.696
Maximum flow rates at confluence using above data:
18.317 15.083
Area of streams before confluence:
3.620 0.280
Results of confluence:
To--al flow rate = 18.317(CFS)
Time of concentration = 6.527 mm.
Effective stream area after confluence =
End of computations, total study area =
3 .900 (Ac.
3.900 (Ac.)
57
VICINITY MAP
NO SCALE
I
San Diego County Hydrology Manual Section: 3 Date: June 2003 Page: 6 of 26
Table 3-1
RUNOFF COEFFICIENTS FOR URBAN AREAS
- Land Use Runoff Coefficient "C"
Soil Type
NRCS Elements County Elements % IMPER. A B C - D
Undisturbed Natural Terrain (Natural) Permanent Open Space 0.20 0.25 0.30 0.35.- 1)56 f4'-
Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32 0.36 0.41
Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46
Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49
Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52
Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57
Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60
Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63
High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71
High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.38 . 0.79
Commercial/Industrial (N. Corn) Neighborhood Commercial 80 0.76 0.77 0.78 0.79
0.82 Commercial/Industrial (G. Corn) General Commercial 85 0.80 0.80 0.81 it€ WTI MAN Commercial/Industrial (0.?. Corn) Office Professional/Commercial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (General U General Industrial 95 0.87 0.87 0.87 0.87
*The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the. pervious runoff
coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the area
is located in Cleveland National Forest).
DU/A dwelling units per acre
NRCS National Resources Conservation Service
3-6
Hydrologic Soil Group—San Diego County Area, California
(La Costa Town Square - Office)
Map Scale: 1:1,540 if printed on A size (8.5" x 11") sheet.
N .Meters 0 20 40 80 iu
-.Feet
0 50 100 200 300
US Natural Resources
Conservation Service 12I9/'O11
Page 1 of 4
Web Soil Survey
National Cooperative Soil Survey
IT 4'52" 4' 2"
.33'4'45"
33" 4'53"
33 4'4
=1
Hydrologic Soil Group—San Diego County Area, California
(La Costa Town Square - Office)
MAP LEGEND MAP INFORMATION
Area of Interest (AOl) Map Scale: 1:1,540 if printed on A size (8.5' x 11") sheet.
Area of Interest (AOl) The soil surveys that comprise your AOl were mapped at 1:24.000.
Soils
Soil Map Units Warning: Soil Map may not be valid at this scale.
Soil Ratings Enlargement of maps beyond the scale of mapping can cause
I A misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
U AID soils that could have been shown at a more detailed scale.
B Please rely on the bar scale on each map sheet for accurate map
UI BID measurements.
LI C Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 11 N NAD83
LII U This product is generated from the USDA-NRCS certified data as of
Not rated or not available the version date(s) listed below.
Political Features Soil Survey Area: San Diego County Area, California
o Cities Survey Area Data: Version 6, Dec 17, 2007
Water Features Date(s) aerial images were photographed: 6/7/2005
Streams and Canals The orthophoto or other base map on which the soil lines were
Transportation compiled and digitized probably differs from the background
-i-I-I- Rails imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
.. Interstate Highways
US Routes
Major Roads
...-,..- Local Roads
USDA Natural Resources Wcb Soil Survey 12/9/2011 Conservation Service National Cooperative Soil SunIey Page 2 of 4
Hydrologic Soil Group—San Diego County Area, California La Costa Town Square - Office
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit - San Diego County Area, California (CA638)
Map unit symbol Map unit name Rating Acres in AOl Percent of AOl
AtE Altamont clay, 15 to 30 percent
slopes
D 3.6 48.3%
F-IrD2 Huerhuero loam, 9 to 15 percent
slopes, eroded
D 3.8 50.6%
SnG San Miguel-Exchequer rocky silt
barns, 9 to 70 percent slopes
D 0.1 1.1%
Totals for Area of Interest 7.5 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (AID, BID, and CID). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (AID, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 12/9/2011 Niiiiiiiii Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—San Diego County Area, California La Costa Town Square - Office
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. None Specified
Tie-break Rule: Higher
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I USDA Natural Resources Web Soil Survey 12/9/2011 Qiiiiiiiiiiiii Conservation Service National Cooperative Soil Survey Page 4 of 4
I
— — — — — — — — — — — — -
— - - -
8
County of San Diego Hydrology Manual
Rainfall Isoplu'ials
-: 3311
1 100 Year K4rnldli Event 6 Hours
(fl)
1
-
E
323O
W4
i 3 0 3 Miles
=I
8
County of San Diego
Hydrology Manual
Cuunty
.5.
Rr '.rsui. Cou iy
—:
Rainjalllsopluvials J.
kO
33115
.
-p 0_S. . S S . •,.• .. . - \ IOU Year Rainfall Event - 24 Hours
• S-
:.-
:
iopLuvIdi
—
r
ENGWOT '
I '
V
'Am 00
--
...............4..
32
LT
171 f so
GIs
-
3230
tL
I
100 30
I-
w
I- LU w z
- 20 0
LU
z
- o z LU
LU
0 -J
0) U-
o C) -
LU LU
0
EXAMPLE:
Given: Watercourse Distance (0) = 70 Feet
Slope (s) =1.3% 1.8 (1.1-C) V15
Runoff Coefficient (C) 0.41 1 = 3\[
Overland Flow Time (1) = 9.5 Minutes
SOURCE: Airport Drainage, Federal Aviation Administration, 1965 ril"i b,
F I G U RE
- Rational Formula - Overland Time of Flow Nomograph
3m3
2.0
Vi1li
I Table 3-2
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3-12
San Diego County Hydrology Manual Section: 3 Date: June 2003 Page: 12 of 26
Note that the Initial Time of Concentration should be reflective of the general land-use at the
upstream end of a drainage basin. A single lot with an area of two or less acres does not have
a significant effect where the drainage basin area is 20 to 600 acres.
Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in
hydrology studies. Initial T1 values based on average C values for the Land Use Element are
also included. These values can be used in planning and design applications as described
below. Exceptions may be approved by the "Regulating Agency" when submitted with a
detailed study.
MAXIMUM OVERLAND FLOW LENGTH (LM)
& INITIAl. TIMI OF CflNr1NTP AT1fl1\T (T.\
Element* DU/
Acre
.5% 1% 2% 3% 5% 10%
LM Tj LM Tj LM T1 LM T1 LM T1 LM T1
Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9
LDR 1 50 12.2 1 70 11.5 1 85 10.0 1 100 9.5 1 100 8.0 1 100 6.4
LDR 2 50 11.3 1 70 10.51 85 9.2 1 100 8.8 100 7.4 100 5.8
LDR 2.9 50 10.7 70 10.01. 85 8.8 1 95 8.1 100 7.0 100 5.6
MDR 4.3 50 10.2 70 9.61 80 8.1 1 95 7.8 100 6.7 100 5.3
MDR 7.3 50 9.2 65 8.4 80 7.4 95 1 7.01 100 6.01 100 4.8
MDR 10.9 1 50 8.71 65 7.9 80 6.9 901 6.41 100 5.71 100 4.5
MDR 14.5 1 50 8.21 65 7.4 80 6.5 90 6.01 100 5.4 1001 4.3
HDR 24 50 6.7 65 6.1 75 5.1 90 4.9 95 4.3 100 3.5
HDR 43 50 5.3 65 4.7 75 4.01 85 3.8 95 3.4 100 2.7
N. Corn 50 5.3 60 4.51 75 4.01 85 3.8 95 3.4 100 2.7
G. Corn 50 4.7 60 4.11 75 3.61 85 3.4 90 2.9 100 2.4
O.P./Com 50 4.2 60 3.71 70 3.1 80 2.9 90 2.61 1001 2.2
Limited 1. 50 4.2 60 3.7 70 3.1 80 1 2.9 90 2.6 100 2.2
General I. 50 3.7 60 3.2 70 2.7 80 2.6 90 :2~.3 100 1.9
*See Table 3-1 for more detailed description
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FIGURE
Nomograph for Determination of
Time of Concentration (Ic) or Travel Time (It) for Natural Watersheds 34