HomeMy WebLinkAboutCT 2019-0002; MADISON FIVE; DRAINAGE REPORT AND STORM WATER STANDARD PROJECT REQUIREMENTS; 2019-08-15DRAINAGE REPORT AND STORM WATER STANDARD PROJECT
REQUIREMENTS
For
MADISON FIVE
CT2019-0002
GR20I 9-0023
DWG5I 8-6A
Southeast Corner of Madison St. & Oak St.
Carlsbad, CA
APN 204-031-01 & 204-031-02
May 17, 2019
Revised: August 15, 2019
R.
To L;1n
CORD COPY
Lfij
itial Date
aCAL
Mel Landy, PE REC.L PREPARED BY:
Jose Sanchez, PE JAN 2 12020
LAND DEVELOPMENT VW1.. ENGNEENGII
HOWES I WElLER I LANDY
PLANNING & ENGINEERING
2888 LOKER AVENUE EAST, SUITE 217
CARLSBAD, CA 92010
(760) 929-2288
TABLE OF CONTENTS
Project Vicinity Map
Introduction...............................................................................2
Existing Drainage Conditions..........................................................4
Proposed Drainage Conditions........................................................4
Methodology...............................................................................4-7
Drainage Summary ......................................................................8
Storm Water Quality Summary.........................................................8-9
Conclusions.................................................................................9
References..................................................................................9
Appendix
I Existing Conditions Calculations - Basin Map
2 Developed Conditions Calculations - Basin Map
3 Storm Water Standard Project Requirements
4 Maps and Charts, Weighted Runoff Coefficient Caic.
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Introduction
This Drainage Study for the proposed five-unit attached residential condominium building
development for APN 204-031-01 and 204-034-02 has been prepared to analyze the
hydrologic and hydraulic characteristics of the existing and proposed project site. This
report intends to present both the methodology and the calculations used for determining
the runoff from the project site in both the pre-developed (existing) conditions and the post-
developed (proposed) conditions produced by the 100-year, 6-hour storm. In addition, this
report will propose the sizing of all necessary storm drain facilities and storm drain piping
to safely convey the runoff, based on the 100-year rainfall event, per County of San Diego
Hydrology and Storm Drain Design Standards.
Elevations range for the project site are approximately 54.0 feet above mean sea level
(mIs) in the south east corner of the site along the alley way to approximately 50.9 feet at
the north west at the intersection of Madison street and Oak Avenue.
The project is within two separate legal lots, known as APN 201-031-01 and 204-031-02,
Lot 15 and 16. The site is located on the southeast corner of Madison street and Oak
Avenue, in the city of Carlsbad, consisting of approximately 0.18 Acres. Said lots are
bordered on the North by Oak Avenue, on the east by an alley, on the west by Madison
Street and on the south by a single family residential property. See Vicinity Map Below.
Project site is currently undeveloped and consists of a small shed at the northwest corner
with fencing round the perimeter of the property. The vegetation within the site consist of
mature trees and palm trees on the eastern portion of the project.
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PROJECT VICINITY MAP
VICINITY MAP
NOT TO SCALE
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Existing Drainage Conditions
Project site has a flat terrain with the high point of the site located on the south east corner
adjacent to the alley with terrain sloping on a north westerly direction towards the
intersection of Oak Ave. and Madison street. The project site does not have any under
ground drainage system to convey flows off site, flows leave the site along the westerly
property line where they comingle with flows from Madison Street and Oak Avenue before
continuing a south westerly direction along Oak Avenue, until they enter an underground
conveyance system located approximately 550 feet from the project site. Eventually flows
discharge into Buena Vista Lagoon.
Proposed Drainage Conditions
The project proposes to create a five-unit multi-family residential site, with new impervious
surfaces which consist of: attached garages, rooftops, walkways, and patio area. The site
will include landscape areas within the frontage of Madison Street and Oak Avenue. There
will be grading activities to level out areas for new improvements, but the drainage patterns
will remain the same.
The project proposes installation of raised planters for water quality purposes and storm
drain systems that will convey flows to the same pre-development discharge points. Due
to the marginal increase of flows that this project will cause on the existing storm drain
system downstream, these flows will be conveyed for a short distance of 1.2 mile before
being discharged at Hedionda Lagoon, therefor mitigation of the increase flows will not be
analyzed.
Study Methodology
The method of analysis was based on the Rational Method according to the San Diego.
Runoff calculations for this study were accomplished by using the Rational Method. The
Rational Method is a physically-based numerical method where runoff is assumed to be
directly proportional to rainfall and area, less losses for infiltration and depression storage.
Flows were computed based on the Rational formula:
Q=CIA
Where Q = Peak discharge (cfs);
C = runoff coefficient, based on land use and soil type
= rainfall intensity (in/hr)
A = watershed area (acre)
(1) Runoff Coefficient, C
Table 4-1 lists the estimated coefficients for urban areas.
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Table 4-1
RUNOFF COEFFICIENT
Hvdrolofr Soil Te
L&ND USE (Coun1-Efrments) Jmperv. A B C D
Pntn'nt Open Space 0.20 0.25 0.30 035 ResitiaI. 1.O DU/A orless 10 0.27 032 0.36 0.41
Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46 ResiiIpntiI 2.9 DU/A or less 25 038 0.41 0.45 0.49
Resii1id43 DU/A orless 30 0.41 0.45 0.48 0.52 Resiia1, 73 DU/A orless 40 0.48 0.51 0.54 057
ResiiaI, 10.9 DU/A or less 45 0.52 0.54 057 0.60
Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63 Resinthil, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71 Resii4'iiiii143O DU/A orless 80 0.76 0.77 0.78 0.79
NeiiboñodComincial 80 0.76 0.77 0.78 0.79 General Conicial 85 0.80 0.80 0.81 0.82 Office Piofessional/Concia1 90 0.83 0.84 0.84 0.85
IiithtedIaIasfria1 90 0.83 0.84 0.81 0.85 Genal Industrial 95 0.87 0.87 0.87 0.87
The runoff coefficient C for this site is calculated as follows pursuant to section 3.1.2 of
the County Hydrology Manual.
The runoff coefficient (C) represents the ratio of rainfall that runs off the watershed versus
the portion that infiltrates to the soil. The runoff coefficient is dependent on the land use
coverage and soil type (Table 4-1). Adjustment have been made to accurately represent
the existing compacted rough graded condition.
See appendix 3, for runoff coefficient calculations, which were prepared based on soil type
and impervious percentage using the formula by the San Diego County Hydrology Manual
C = 0.90 x (% Impervious) + Cp x (1 - % Impervious)
Where: Cp = Pervious Coefficient Runoff Value for the soil type (shown in Table 3-1 as
Undisturbed Natural Terrain/Permanent Open Space, 0% Impervious). Soil type can be
determined from the soil type map provided in Appendix 4 of the San Diego County
Hydrology Manual. The project site consist of soil type B.
(2) Rainfall Intensity, I
Average rainfall intensity for a duration equal to the Tc for the area, in inches per hour.
The storm frequency for this study has a 100-year recurrence interval. The six-hour
anticipated precipitation for the project site subject to the design storm frequency.
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P6 = 2.55 in
P24 = 4.5 in
P6 is in the range of 45% to 65% of P24 and therefore doesn't need to be adjusted.
The RM equation assumes that the storm event being analyzed delivers precipitation to
the entire basin uniformly, and therefore the peak discharge rate will occur when a raindrop
falls at the most remote portion of the basin arrives at the point of analysis. The RM also
assumes that the fraction of rainfall that becomes runoff or the runoff coefficient C is not
affected by the storm intensity, I, or the precipitation zone number.
(1) Time of Concentration. Ic
The time of concentration is the time required for runoff to flow from the most remote part
of the watershed to the outlet point under consideration.
The time of concentration for each sub-area on site, Tc is determined from the following
formula (San Diego County Hydrology Manual, dated June 2003) with the initial lengths
and times adjusted per Table 3-2 of the Manual for slope and land use.
T = 1.8(1.1— C)J (For overland time of flow) vi
Where,
7; = Time of Concentration (hours)
D= Watercourse Distance (ft)
3= Slope (%)
C= Runoff Coefficient
(i19L)°
(For natural watersheds
Where,
7; = Time of Concentration in hours (hours)
L= Watercourse Distance (miles)
AE = Change in elevation along effective slope line (ft)
The average rainfall intensity is calculated from the following equation (San Diego County
Hydrology Manual, June 2003).
1= 7.44xP xD °°'
Where,
I= Rainfall Intensity (in/hr)
= Six hour precipitation (inches)
D = Duration (mm.)
There is an illustration of this formula in Figure 2, which is per County 2003 Hydrology
Manual. Time of concentration (Ic) is composed of two components: The initial time of
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concentration (Ij), and the travel time (Tt).
The maximum overland flow length (LM) is used from Table 4 in calculating the initial time
of concentration. The source for this chart is the San Diego County Hydrology Manual
(Table 3.2), June 2003.
Table 4- Maximum Overland Flow Length (La) & Initial Time of Concentration (Ti)
,Element DU/
Acre
5_i L9LiOL
LM I Ti LM Ti L1 I Ti LM I Ti I L, Ti I LM I Ti
Natural 50 1 13.2170 12.5 95110.9 100 10.3 100 8.71100 6.9
1LDR 1 50 12.2 70 11.5 85110.0 10019.5 100 8.01100 6.4
LDR 2 50 11.3 70 10.518J 1 9.2 10018.8 1007.41100 5.8
LDR 2.9 50 103.0 70 10.0 1 85 8.8 95 1 8.1 10017.01100 5.6
'MDR 4.3 501 10.2 70 9.6 80 8.1 95 7.8 10016.7 100 5.3
,MDR 7.3 501 9.2 65 8.4 80 7.4 95 7.0 tOO 6.0 100 4.8
10.9 50 8.7 65 7.9 80 6.9 90 6.4 100 5.7 100 4.5
MDR 14.5 50 8.2 65 7.4 80 6.5 90 6.0 100 5.4 tOO 4.3
IR 24 50 6.7 65 6.1 175 5.1 90 14.9 95 4.31100 3.5
43 50 5.3 65 4.7 175 4.0 85 3.8 95 3.41100 2.7
N. Coin. 501 5.3 60 4.5 175 4.0 85 3.8 95 3.4 100 2.7
1G. Corn. 501 4.7 60 4.1 17513.6 85 3.4 90 2.9 100 2.4
tO.PJCom. 50 41.0 60 3.7 7013.1 80 2.9 90 2.6 100 2.2
LirnitcdI. 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 tOO 2.2
'General 50 3.7 60 3.2 70 2.7 80 2.6 90 2.3 100 1.9
In addition to the above Ration Method assumptions, the conservative assumption that all
runoff coefficients utilized for this report are based on Type "B"
The County of San Diego Rational Method program within CivilDesign was utilized in
calculating runoff for all basins smaller than 0.5 square miles in size.
Drainage Summary
Upon performing hydrologic analysis of the project site in both the proposed developed
and existing condition, the following results were produced:
Table I - Summary of existing conditions
BASIN / Node Effective
C
Tc (mm.) I in/hr Area (ac)
Total
Qpeak (cfs)
Total A/15 0.27 11.6 3.91 0.18 0.19
Total -- -- -- 0.18 1 0.19
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Table 2— Summary of developed conditions
BASIN I Node Effective
C
Tc (mm.) I in/hr Area (ac)
Total
Qpeak (cfs)
Total A/17 0.78 4.05 6.72 0.11 0.58 B/30 0.71 5.73 1 6.15 1 0.07 1 0.31 TOTAL -- - -- 0.18 1 0.84
As shown on tables above, there will be an increase in a 100-year storm event in the
proposed condition of 0.65 CFS. Said increase will not have a detrimental effect on the
existing underground conveyance system that site flows ultimately enter. At the upstream
of the existing system a 30" RCP storm drain conveys 21.3 cfs during the 100-year storm
event per DWG 365-2, the additional flows from the project site represent a 3% increase
in the most upper portion of the system. Further downstream the system becomes a 54"
RCP Storm drain conveying 75 cfs during the 100-year storm event per DWG 360-5,
meaning that the increase in flows from the project site represents an increase of 0.86%
which is marginal. See Appendix 4, for the record drawings stated above.
Storm water Quality Summary
This project has been determined to be a "Standard Project" per the City of Carlsbad Storm
Water Standards Questionnaire (E-34) and is therefore exempt from priority project
requirements. The development proposes to reduce the discharge of pollutants offsite by
utilizing source control and Site Design Low Impact Development (LID) BMP's to the
maximum extent possible.
The project proposed landscaping and ground cover along the frontage of Madison Street
and Oak Avenue. Roof downspouts will convey flows to eight (8) total planters within the
project site. Five (5) raised planters are fronting Oak Avenue, two (2) raised planters
fronting Madison Street, and one (1) ground planter is located at the south east corner of
unit 3, which will be constructed with impermeable liner around the perimeter and along
portion of unit 3 foundation (acting as a cutoff wall) to avoid lateral migration of infiltration
under the building. Said planters will discharge flows via curb outlets at the
predevelopment discharge point.
As shown in Table I and Table 2, the project has increase peak flows in the unmitigated
100-year storm condition, as stated before the peak flow increase is marginal in the overall
Q being conveyed by the existing storm drain system.. Furthermore the project flows will
be conveyed for a short distance of 1.2 miles before ultimately being discharged at
Hedionda Lagoon, therefor mitigation of the increase flows will not be analyzed.
The raised planters will be integrated with the landscape design to provide treatment to
storm water runoff generated on-site before discharging runoff in a control manner.
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Conclusions
The proposed storm drain system was designed in accordance with the guidelines set by
the County of San Diego. During the design of the proposed drainage systems precautions
were taken to limit adverse downstream affects and to maintain existing drainage
characteristics wherever possible.
A summary of the facts and findings associated with this project and the measures
addressed by this report is as follows:
The project will not significantly alter drainage patterns on the site.
The ultimate discharge points will not be changed.
Graded areas and slopes will be landscaped to reduce or eliminate sediment
discharge.
The storm drain system .for the project is designed to route and convey all resulting
runoff from developed conditions to the existing points of discharge.
Existing down stream underground conveyance system will not be detrimentally
impacted.
References
"San Diego County Hydrology Manual": revised June 2003, County of San Diego,
Department of Public Works, Flood Control Section.
"California Regional Water Quality Control Board Order No. 2001-07, "California Regional
Water Control Board, San Diego Region (SDRWQCB).
"City of Carlsbad BMP Design Manual" February 2016, Edition
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Existing Conditions Calculations & Drainage Map
I
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SCALE: 1" = 20
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HOWES I WElLER I LANDY PLANNING & ENGINEERING DATE
Tel. 760.929.88 Fax. 760.929.2287
2888 LOKER AVENUE EAST SUITE 217
CARLSBAD, CA 92010
LEWD
1W
BASIN
BOUNDARY
SUBBA SIN
BOUNDARY
DRAINAGE
DIRECTiON
BASIN
OAKAVE AND MADISON ST
PRE-DEVELOPMENT CONDITION
DRAINAGE EXHIBIT
IDRAY,1NG:
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1/17/19 rSHEET 1 OF 1
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DRAINAGE
DESCRIPTiON
NODE
EX /MPERI4OUS
San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c)1991-2009 Version 7.8
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 12/11/18 -------------------------------------------------------------
Oak Ave. & Madison St.
Pre-Development Condition
100-Tear Storm Event
********* Hydrology Study Control Information ********** ----------------------------------------------------------
Program License Serial Number 6290
-------------------------------------------------------
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipitation(inches) = 2.550
24 hour precipitation(inches) = 4.500
P6/P24 = 56.7%
San Diego hydrology manual 'C' values used
Process from Point/Station 5.000 to Point/Station 10.000 INITIAL AREA EVALUATION ****
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 1.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
[UNDISTURBED NATURAL TERRAIN
(Permanent Open Space )
Impervious value, Ai = 0.000
Sub-Area C Value = 0.250
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 53.800(Ft.)
Lowest elevation = 52.900(Ft.)
Elevation difference = 0.900(Ft.) Slope = 1.800 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 85.00 (Ft)
for the top area slope value of 1.80 %, in a development type of
Permanent Open Space
In Accordance With Figure 3-3
Initial Area Time of Concentration = 11.60 minutes
TC = [1.8*(1.1_C)*distance(Ft.)A.5)/(% slope A(1/3)]
PC = [1.8*(1.1_0.2500)*( 85.000A.5)/( 1.800A(1/3)J= 11.60
Rainfall intensity (I) = 3.905(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.250 Subarea runoff = 0.039(CFS)
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Total initial stream area = 0.040(Ac.)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.++++
Process from Point/Station 10.000 to Point/Station 15.000 **** SUBAREA FLOW ADDITION ****
Rainfall intensity (I) = 3.905(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.270 given for subarea
Time of concentration = 11.60 mm.
Rainfall intensity = 3.905(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.266 CA = 0.048
Subarea runoff = 0.148(CFS) for 0.140(Ac.)
Total runoff = 0.187(CFS) Total area = 0.180(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 15.000 to Point/Station 15.000 **** CONFLUENCE OF MINOR STREAMS
Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.180(Ac.)
Runoff from this stream = 0.187(CFS)
Time of concentration = 11.60 mm.
Rainfall intensity = 3.905(In/Hr)
Summary of stream data:
Stream Flow rate TC
No. (CFS) (mm)
1 0.187 11.60
Qmax(1) =
1.000 * 1.000 *
Rainfall Intensity
(In/Hr)
3.905
0.187) + = 0.187
Total of 1 streams to confluence:
Flow rates before confluence point:
0.187
Maximum flow rates at confluence using above data:
0.187
Area of streams before confluence:
0.180
Results of confluence:
Total flow rate = 0.187(CFS)
Time of concentration = 11.596 min.
Effective stream area after confluence = 0.180(Ac.)
End of computations, total study area = 0.180 (Ac.)
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APPENDIX 2.
Developed Conditions Calculations & Drainage Map
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San Diego County Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1991-2009 Version 7.8
Rational method hydrology program based on
San Diego County Flood Control Division 2003 hydrology manual
Rational Hydrology Study Date: 01/17/19 -----------------------------------------------------------
Oak ave and Madison Street
Post-Development
100-Tear Storm Event
-----------------------------------------------------------
********* Hydrology Study Control Information -----------------------------------------------------------
Program License Serial Number 6290
Rational hydrology study storm event year is 100.0
English (in-lb) input data Units used
Map data precipitation entered:
6 hour, precipiation(inches) = 2.550
24 hour precipitation(inches) = 4.500
P6/P24 = 56.7%
San Diego hydrology manual 'C' values used
BASIN A
Process from Point/Station 5.000 to Point/Station 10.000
INITIAL AREA EVALUATION ****
A.1
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 1.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
[INDUSTRIAL area type
(Limited Industrial
Impervious value, Ai = 0.900
Sub-Area C Value = 0.840
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 53.500(Ft.)
Lowest elevation = 52.750(Ft.)
Elevation difference = 0.750(Ft.) Slope = 1.500 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 70.00 (Ft)
for the top area slope value of 1.50 %, in a development type of
Limited Industrial
In Accordance With Figure 3-3
Initial Area Time of Concentration = 3.42 minutes
TC = [1.8*(1.1_C)*distance(Ft.).5)/(% slope"(1/3)]
TC= [1.8*(1.1_0.8400)*( 70.000A.5)/( 1.500'(1/3)J= 3.42
Calculated TC of 3.421 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 6.719(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.840
Subarea runoff = 0.226(CFS)
Total initial stream area = 0.040(Ac.)
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 15.000
**** SUBAREA FLOW ADDITION ****
A.2
Calculated TC of 3.421 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 6.719(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.790 given for subarea
Time of concentration = 3.42 mm.
Rainfall intensity = 6.719(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.810 CA = 0.081
Subarea runoff = 0.318(CFS) for 0.060(Ac.)
Total runoff = 0.544(CFS) Total area = 0.100 (Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 15.000
PIPEFLOW TRAVEL TIME (User specified size) ****
Upstream point/station elevation = 50.590(Ft.)
Downstream point/station elevation = 49.850(Ft.)
Pipe length = 105.00(Ft.) Slope = 0.0070 Manning's N = 0.012
No. of pipes = 1 Required pipe flow = 0.544(CFS)
Given pipe size = 6.00(In.)
NOTE: Normal flow is pressure flow in user selected pipe size.
The approximate hydraulic grade line above the pipe invert is
0.280(Ft.) at the headworks or inlet of the pipe(s)
Pipe friction loss = 0.841(Ft.)
Minor friction loss = 0.179(Ft.) K-factor = 1.50
Pipe flow velocity = 2.77(Ft/s)
Travel time through pipe = 0.63 mm.
Time of concentration (TC) = 4.05 mm.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 17.000 to Point/Station 17.000
**** SUBAREA FLOW ADDITION ****
A.3
Calculated TC of 4.052 minutes is less than 5 minutes,
resetting TC to 5.0 minutes for rainfall intensity calculations
Rainfall intensity (I) = 6.719(In/Hr) for a 100.0 year storm
User specified 'C' value of 0.540 given for subarea
Time of concentration = 4.05 mm.
Rainfall intensity = 6.719(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for total area
(Q=KCIA) is C = 0.785 CA = 0.086
Subarea runoff = 0.036(CFS) for 0.010(Ac.)
Total runoff = 0.580(CFS) Total area = 0.110(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 17.000 to Point/Station 17.000
**** CONFLUENCE OF MINOR STREAMS
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Along Main Stream number: 1 in normal stream number 1
Stream flow area = 0.110 (Ac.)
Runoff from this stream = 0.580(CFS)
Time of concentration = 4.05 mm.
Rainfall intensity = 6.719(In/Hr)
Summary of stream data:
Stream Flow rate TC Rainfall Intensity
No. (CFS) (mm) (In/Hr)
1 0.580 4.05 6.719
Qmax(1) =
1.000 * 1.000 * 0.580) + = 0.580
Total of 1 streams to confluence:
Flow rates before confluence point:
0.580
Maximum flow rates at confluence using above data:
0.580
Area of streams before confluence:
0.110
Results of confluence:
Total flow rate = 0.580(CFS)
Time of concentration = 4.052 mm.
Effective stream area after confluence = 0.110(Ac.)
BASIN B
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 20.000 to Point/Station 25.000
INITIAL AREA EVALUATION ****
B.1
Decimal fraction soil group A = 0.000
Decimal fraction soil group B = 1.000
Decimal fraction soil group C = 0.000
Decimal fraction soil group D = 0.000
[HIGH DENSITY RESIDENTIAL
(24.0 DU/A or Less
Impervious value, Ai = 0.650
Sub-Area C Value = 0.670
Initial subarea total flow distance = 50.000(Ft.)
Highest elevation = 53.300(Ft.)
Lowest elevation = 52.300(Ft.)
Elevation difference = 1.000(Ft.) Slope = 2.000 %
Top of Initial Area Slope adjusted by User to 1.600 %
INITIAL AREA TIME OF CONCENTRATION CALCULATIONS:
The maximum overland flow distance is 75.00 (Ft)
for the top area slope value of 1.60 %, in a development type of
24.0 DU/A or Less
In Accordance With Figure 3-3
Initial Area Time of Concentration = 5.73 minutes
TC = [1.8*(l.l_C)*distance(Ft.)A.5)/(% slope"(1/3)1
TC = [1.8*(1.10.6700)*( 75.000'.5)/( 1.600'(1/3)1= 5.73
Rainfall intensity (I) = 6.153(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.670
Subarea runoff = 0.082(CFS)
Total initial stream area = 0.020(Ac.)
Page 116 of 77 DRAINAGE REPORT
Madison Five
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 25.000 to Point/Station 30.000 **** SUBAREA FLOW ADDITION ****
B.2
Rainfall intensity (I) = 6.153(In/Hr) for a 100.0 year storm User specified 'C' value of 0.730 given for subarea
Time of concentration = 5.73 mm.
Rainfall intensity = 6.153(In/Hr) for a 100.0 year storm Effective runoff coeffiàient used for total area
(Q=KCIA) is C = 0.713 CA = 0.050
Subarea runoff = 0.225(CFS) for 0.050(Ac.)
Total runoff = 0.307(CFS) Total area = 0.070(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 35.000 to Point/Station 35.000 **** CONFLUENCE OF MINOR STREAMS ****
Along Main Stream number: 1 in normal stream number 2
Stream flow area = 0.070(Ac.)
Runoff from this stream = 0.307(CFS)
Time of concentration = 5.73 mm.
Rainfall intensity = 6.153(In/Hr)
Summary of stream data:
Stream Flow rate PC
No. (CFS) (mm)
1 0.580 4.05
2 0.307 5.73
Qmax(1) =
1.000 * 1.000 *
1.000 * 0.707 *
Qmax(2) =
0.916 * 1.000 *
1.000 * 1.000 *
Rainfall Intensity
(In/Hr)
6.719
6.153
0.580) +
0.307) + = 0.798
0.580) +
0.307) + = 0.839
Total of 2 streams to confluence:
Flow rates before confluence point:
0.580 0.307
Maximum flow rates at confluence using above data:
0.98 0.839
Area of streams before confluence:
0.110 0.070
Results of confluence:
Total flow rate = 0.839(CFS)
Time of concentration = 5.731 mm.
Effective stream area after confluence = 0.180(Ac.)
End of computations, total study area = 0.180 (Ac.)
Page I 17of77 DRAINAGE REPORT
Madison Five
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APPENDIX 3
Storm Water Standard Project Requirements
Page J 18 of 77 DRAINAGE REPORT
Madison Street & Oak Avenue
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STORM WATER STANDARDS Development Services (City of
Carlsbad QUESTIONNAIRE Land Development Engineering
1635 Faraday Avenue E-34 (760) 602-2750
www.carlsbadca.gov
INSTRUCTIONS:
To address post-development pollutants that may be generated from development projects, the city requires that new
development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management
Practices (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual,
refer to the Engineering Standards (Volume 5).
This questionnaire must be completed by the applicant in advance of submitting for a development application
(subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of
storm water standards that must be applied to a proposed development or redevelopment project. Depending on the
outcome, your project will either be subject to 'STANDARD PROJECT' requirements or be subject to 'PRIORITY
DEVELOPMENT PROJECT' (PDP) requirements.
Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City
staff has responsibility for making the final assessment after submission of the development application. If staff
determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than
initially assessed by you, this will result in the return of the development application as incomplete. In this case, please
make the changes to the questionnaire and resubmit to the city.
If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the
questions, please seek assistance from Land Development Engineering staff.
A completed and signed questionnaire must be submitted with each development project application. Only one
completed and signed questionnaire is required when multiple development applications for the same project are
submitted concurrently.
PROJECT INFORMATION S S
PROJECT NAME: Oak Ave. & Madison St. PROJECT ID:
ADDRESS: Southeast corner of Madison Street and Oak Avenue APN: 201-031-01-00 AND 204-031-02-00
The project is (check one): 91 New Development 0 Redevelopment
The total proposed disturbed area is: 7,929 ft2 ( 0.18 ) acres
The total proposed newly created and/or replaced impervious area is: 6,088 ft2 (_0.14 ) acres
If your project is covered by an approved SWQMP as part of a larger development project, provide the project ID and the
SWQMP # of the larger development project:
Project ID SWQMP #:
Then, go to Step I and follow the instructions. When completed, sign the form at the end and submit this with your
application to the city.
E-34 Page lof4 REV 02/16
STEP I
TO BE COMPLETED FOR ALL PROJECTS
To determine if your project is a "development project', please answer the following question:
YES NO
Is your project LIMITED TO routine maintenance activity and/or repair/improvements to an existing building o ii or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for guidance)?
If you answered 'yes' to the above question, provide justification below then go to Step 5, mark the third box stating "my project is not a 'development project' and not subject to the requirements of the BMP manual' and complete applicant
information.
Justification/discussion: (e.g. the project includes only interior remodels within an existing building):
If you answered "no' to the above question, the project is a 'development project', go to Step 2.
STEP 2
TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS
To determine if your project is exempt from PDP requirements pursuant to MS4 Permit Provision E.3.b.(3), please answer
the following questions:
Is your project LIMITED to one or more of the following:
YES NO 1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria:
Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non-
erodible permeable areas; o i Designed and constructed to be hydraulically disconnected from paved streets or roads;
Designed and constructed with permeable pavements or surfaces in accordance with USEPA
Green Streets guidance?
2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in Cl In accordance with the USEPA Green Streets guidance?
3. Ground Mounted Solar Array that meets the criteria provided in section 1.4.2 of the BMP manual? D II
If you answered "yes' to one or more of the above questions, provide discussion/justification below, then go to Step 5, mark the second box stating "my project is EXEMPT from PDP ...' and complete applicant information.
Discussion to justify exemption ( e.g. the project redeveloping existing road designed and constructed in accordance with
the USEPA Green Street guidance):
If you answered "no' to the above questions, your project is not exempt from PDP, go to Step 3.
E-34 Page 2of4 REV 04/17
STEP 3
TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS
To determine if your project is a POP, please answer the following questions (MS4 Permit Provision E.3.b.(1)):
YES NO Is your project a new development that creates 10,000 square feet or more of impervious surfaces
- collectively over the entire project site? This includes commercial, industrial, residential, mixed-use, 0 IJ and public development projects on public or private land.
Is your project a redevelopment project creating and/or replacing 5,000 square feet or more of
impervious surface collectively over the entire project site on an existing site of 10,000 square feet or
more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public
development projects on public or private land.
Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is
a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and 0 EJ refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial
Classification (SIC) code 5812).
Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious
surface collectively over the entire project site and supports a hillside development project? A hillside D I1 development project includes development on any natural slope that is twenty-five percent or greater.
Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious surface collectively over the entire project site and supports a parking lot? A parking lot is
a land area or facility for the temporary parking or storage of motor vehicles used personally for
business or for commerce.
Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious street, road, highway, freeway or driveway surface collectively over the entire project
site? A street, road, highway, freeway or driveway is any paved impervious surface used for the
transportation of automobiles, trucks, motorcycles, and other vehicles.
Is your project a new or redevelopment project that creates and/or replaces 2,500 square feet or more
of impervious surface collectively over the entire site, and discharges directly to an Environmentally
Sensitive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of 0 FRI 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an
isolated flow from the project to the ESA (i.e. not commingled with flows from adjacent lands).* Is your project a new development or redevelopment project that creates and/or replaces 5,000 square
feet or more of impervious surface that supports an automotive repair shop? An automotive repair shop is a facility that is categorized in any one of the following Standard Industrial Classification (SIC)
codes: 5013, 5014, 5541, 7532-7534, or 7536-7539.
Is your project a new development or redevelopment project that creates and/or replaces 5,000 square
feet or more of impervious area that supports a retail gasoline outlet (RGO)? This category includes El El RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily
Traffic (ADT) of 100 or more vehicles per day.
Is your project a new or redevelopment project that results in the disturbance of one or more acres of land
and are expected to generate pollutants post construction?
Is your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of
- impervious surface or (2) increases impervious surface on the property by more than 10%? (CMC 0 t) 21.203.040)
If you answered "yes" to one or more of the above questions, your project is a PDP. If your project is a redevelopment
project, go to step 4. If your project is a new project, go to step 5, check the first box stating "My project is a PDP
. and complete applicant information.
If you answered "no' to all of the above questions, your project is a STANDARD PROJECT.' Go to step 5, check the
second box stating "My project is a 'STANDARD PROJECT'..." and complete applicant information.
E-34 Page 3of4 REV 04117
STEP 4
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP)
ONLY
Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)):
YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount
of less than 50% of the surface area of the previously existing development? Complete the percent
impervious calculation below:
Existing impervious area (A) = sq. ft. 0 0
Total proposed newly created or replaced impervious area (B) = sq. ft.
Percent impervious area created or replaced (B/A)*100 = %
If you answered yes, the structural BMPs required for PDP apply only to the creation or replacement of impervious
surface and not the entire development. Go to step 5, check the first box stating My project is a PDP ... and complete applicant information.
If you answered no," the structural BMP's required for PDP apply to the entire development. Go to step 5, check the
check the first box stating My project is a PDP ..." and complete applicant information.
STEP 5
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
O My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must
prepare a Storm Water Quality Management Plan (SWQMP) for submittal at time of application.
II My project is a 'STANDARD PROJECT' OR EXEMPT from PDP and must only comply with STANDARD PROJECT'
stormwater requirements of the BMP Manual. As part of these requirements, I will submit a Standard Project Requirement Checklist Form E-36" and incorporate low impact development strategies throughout my project.
Note: For projects that are close to meeting the PDP threshold, staff may require detailed impervious area calculations
and exhibits to verify if 'STANDARD PROJECT' stormwater requirements apply.
U My Project is NOT a 'development project' and is not subject to the requirements of the BMP Manual.
Applicant Information and Signature Box
Applicant Name: Jose Sanchez Applicant Title: Proiect Engineer
Applicant Signature: 094 1154dfC43 Date: 2/I2/I9
- Environmentally Sensitive Areas Include but are not limited to all Clean Water Pt Section 303(d) impaired water bodies; areas designated as Areas 01 special
Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies
designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and
amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; Habitat
Management Plan; and any other equivalent environmentally sensitive areas which have been identified by the City.
This Box for City Use On/v
City Concurrence:
YES NO
o o
By:
Date:
Project ID:
E-34 Page 4of4 REV 04/17
Coty of
Carlsbad
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 602-2750
www.carlsbadca.gov
Project Information
Project Name: Madison Five
Project ID: CT2019-0002
DWG No. or Building Permit No.: 518-6A
Source Control BMPs
All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See
Chapter 4 and Appendix E.1 of the BMP Design Manual (Volume 5 of City Engineering Standards) for information to
implement source control BMPs shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1 of the
Model BMP Design Manual. Discussion/justification is not required.
"No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed.
"N/A" means the BMP is not applicable at the project site because the project does not include the feature that is
addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussionljustification may be provided.
Source Control Requirement Applied?
SC-1 Prevention of Illicit Discharges into the MS4 Ill Yes 0 No 0 N/A Discussion/justification if SC-I not implemented:
SC-2 Storm Drain Stenciling or Signage 0 Yes 1 0 No 11 N/A Discussion/justification if SC-2 not implemented:
No storm drain inlets or catch basins are being proposed.
SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind
ijj Yes 0 No 0 N/A Dispersal
Discussion/justification if SC-3 not implemented:
E-36 Page 1 of 4 Revised 09/16
Source Control Requirement (continued) Applied? SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and
Wind Dispersal 0 Yes 0 No 11 N/A
Discussion/justification if SC-4 not implemented:
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal 1k Yes 0 No 0 N/A Discussion/justification if SC-5 not implemented:
SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below and
identify additional BMPs. (See Table in Appendix E.1 of BMP Manual for guidance).
On-site storm drain inlets 0 Yes 0 No 1k N/A
Interior floor drains and elevator shaft sump pumps 0 Yes 0 No lJ N/A
Interior parking garages 0 Yes 0 No 1k N/A
kl Need for future indoor & structural pest control 1k Yes 0 No 0 N/A
9 Landscape/Outdoor Pesticide Use 1k Yes 0 No 0 N/A Pools, spas, ponds, decorative fountains, and other water features 0 Yes 0 No 9 N/A
Food service 0 Yes 0 No 0 N/A
1k Refuse areas 1k Yes 0 No 0 N/A
E3 Industrial processes 0 Yes 0 No I! N/A
Outdoor storage of equipmentor materials 0 Yes 0 No 0 N/A
Vehicle and Equipment Cleaning 0 Yes 0 No 1k N/A
Vehicle/Equipment Repair and Maintenance 0 Yes 0 No 11 N/A
Fuel Dispensing Areas 0 Yes 0 No 1k N/A
Loading Docks 0 Yes 0 No 1k N/A
1k Fire Sprinkler Test Water Iii Yes 0 No 0 N/A
Miscellaneous Drain or Wash Water 0 Yes _0 _No 1k N/A Plazas, sidewalks, and parking lots 9 Yes 0 No T70 N/A For 'Yes" answers, identify the additional BMP per Appendix El. Provide justification for "No" answers.
-building design features will discourage entry of pest, provide integrated pest management information
to owners, lessees, and operators.
-Pest-resistant plants, maintain landscape using minimal or no pesticides.
-Trash cans to be located inside each residence an only taken out during trash day.
-drive aisle to be swept regularly to prevent accumulation of litter and debris.
E-36 Page 2 of 4 Revised 09/16
Site Design BMPs
All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See
Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual (Volume 5 of City Engineering Standards) for information
to implement site design BMPs shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the site design BMPs as described in Chapter 4 and/or Appendix E.2 thru E.6 of
the Model BMP Design Manual. Discussion /justification is not required.
"No" means the BMPs is applicable to the project but it is not feasible to implement. Discussion/justification must be
provided. Please add attachments if more space is needed.
"N/A" means the BMPs is not applicable at the project site because the project does not include the feature that is
addressed by the BMPs (e.g., the project site has no existing natural areas to conserve). Discussion/justification may be
provided.
Site Design Requirement Applied? SD-1 Maintain Natural Drainage Pathways and Hydrologic Features @ Yes 1 0 No I 0 N/A Discussion/justification if SD-i not implemented:
SD-2 Conserve Natural Areas, Soils, and Vegetation
. I 0 Yes I 0 No I ci N/A Discussion/justification if SD-2 not implemented:
SD-3 Minimize Impervious Area I 0 Yes I lJ No I 0 N/A Discussion/justification if SD-3 not implemented:
project maximized development area, majority of site is impervious
SD4 Minimize Soil Compaction I 0 Yes I H No I 0 N/A Discussion/justification if SD-4 not implemented:
unable to minimize soil compaction since majority of site is impervious developed area where soil
compaction is required.
SD-5 Impervious Area Dispersion I ii Yes I 0 No I 0 N/A Discussion/justification if SD-5 not implemented:
E-36 Page 3 of 4 Revised 09/16
Site Design Requirement (continued) Applied? SD-6 Runoff Collection 9 Yes 0 No J 0 N/A Discussion/justification if SD-6 not implemented:
SD-7 Landscaping with Native or Drought Tolerant Species I ii Yes I 0 No I 0 N/A Discussion/justification if SD-7 not implemented:
SD-8 Harvesting and Using Precipitation I 0 Yes I 0 No J I1 N/A Discussion/justification if SD-8 not implemented:
E-36 Page 4 of 4 Revised 09/16
APPENDIX 4
Maps and Charts
Page 119 of 77 DRAINAGE REPORT
Madison Five
wwwiiwL-PE.COM 2888 Loker Avenue East, Suite 217, Carlsbad, CA 920101 Tel. 760.929.22881 Email. info@HWL-PE.COM
Madison Five
7/25/2019
Pre-Project Drainage
Pervious Impervious
Total Area - Soil Area - Soil Weighted
Area Type B Type B Runoff Coeff
Basin ID (ac) (sq-ft) (sq-ft) % Impervious % Pervious C:
A.1 0.05 1963 0 1 100% 0% 0.25
A.2 0.14 5806 158 1 97% 3% 0.27
Total 0.18 AC
Runoff Coefficient Table
Soil Type B
Impervious 0.90
Pervious (landscape) 0.25
Post-Project Drainage
Basin ID
Total
Area
(ac)
Pervious
Area - Soil
Type B
(sq-ft)
Impervious
Area - Soil
Type B
(sq-ft) % Pervious % Impervious
Weighted
Runoff Coef
C:
A.1 1 0.04 91 1434 1 6% 94% 0.86
A.2 0.06 477 2333 17% 83% 0.79
A.3 0.01 327 266 55% 45% 0.54
B.1 0.02 370 670 36% 1 64% 1 0.67
B.2 0.05 558 1627 26% 1 74% 1 0.73
Total 0.18 AC
S:\PROJECTS\19201 OAK AND MADISON\CIVIL\REPORTS\HYDROLOGY\FinaI Engineering\Appendix 4- Weighted
Runoff Coefficient\Oak and Mad ison_drn_calcs.xlsx
Watershed Divide
.00
Design
Point
Watershed
Divide
4E I ign Point 70fffewtfive Slope Une (Watershed outlet)
Stream Profile
I_______________
Area A" . Area
SOURCE Catfo,sa OWilon of Kgtraays (12) and Kirpich (t)
FIGURE
Computation of Effective Slope for Natural Watersheds 35 39
Page p Z() ot II DRAINAGE REPORT
Madison Five
www.HWL.PE.COM 2888 Loker Avenue East, Suite 217 Carlsbad, CA 920101 Tel. 760.929.22881 Email. info@HWL-PE.COM
SIflNM NI 3WI1 M01A ONYThIRAO a ('4 a U
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Page 1 21 of 77 DRAINAGE REPORT
Madison Five
www.HWL-PE.COM 2888 Loker Avenue East, Suite 217, Carlsbad, CA 92010 1 Tel. 760.929.22881 Email. info@HWL-PE.COM
Manning's n Values for Overland Flow'
The BMP Design Manuals within the County of San Diego allow for a land surface description other than
short prairie grass to be used for hydromodification OMP design only if documentation provided Is
consistent with Table A.6 of the SWMM 5 User's Manual.
In January 2016, the EPA released the SWMM Reference Manual Volume I - Hydrology (SWMM
Hydrology Reference Manual). The SWMM Hydrology Reference Manual complements the SWMM 5
User's Manual by providing an in-depth description of the program's hydrologic components. Table 3-5
of the SWMM Hydrology Reference Manual expounds upon Table A.6 of the SWMM 5 User's Manual by
providing Manning's n values for additional overland flow surfaces. Therefore, in order to provide
SWMM users with a wider range of land surfaces suitable for local application and to provide
Copermittees with confidence In the design parameters, we recommend using the values published by
Yen and chow in Table 3-5 of the EPA SWMM Reference Manual Volume I - Hydrology. The values are
provided in the table below:
Overland Surface Manning value (a)
Smooth asphalt pavement 0.010
Smooth impervious surface 0.011
Tar and sand pavement 0.012
Concrete pavement 0.014
Rough impervious surface 0.015
Smooth bare packed soil 0.017
Moderate bare packed soil 0.025
Rough bare packed soil 0.032
Gravel soil 0.025
Mowed poor grass 0.030
Average grass, closely clipped sod 0.040
Pasture 0.040
Timberland 0.060
Dense grass 0.060
Shrubs and bushes 0.080
Land Use
Business 0.014
Semibusiness 0.022
Industrial 0.020
Dense residential 0.025
Suburban residential 0.030
Parks and lawns 0.040
'Content summarized from improving Accuracy In Continuous Simulation Modeling: Guidance for
Selecting Pervious Overland Flow Manning's n Values in the Son Diego Region (TRWE, 2016).
Page 122 of 77 DRAINAGE REPORT
Madison Five
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EQUATION AE
Tc lit 91.3%0385 • 1Fee
1- s000 TC Time of cuncintretlu,i (hours)
L Waoo Distance cmie)
4000 AE • Change In elevation along
effective slope line (See Figure 3-5) (lest)
Tc
Hews Minutes
1:— 2000 • 240
3 160
1000 900
100 2 120
100
00
soo\ so
°° 10
• 1-60 300
50 S.
5' 200 40
5' L UliesFed —30 5'
5'1 100 5'
20
5' Is
3000 II
50 0.5 14
40 2000 12 Inc 1600 5' ID —30 1400 S.
1200 a
20 1000 7 SOS
SOD 0 100
605 $
10 500
.-200
AE L ic
CaomIa DI4SIOIiC( 11Igtroy5 (1941) and Krpch (1040)
U RE
Nomograph for Determination of
lime of Concentration (Ic) or Travel Time (TI) for Natural watersheds 3.4 217
Page 1 23 of 77 DRAINAGE REPORT
Madison Five
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Hydrologic Soil Group—San Diego County Area, California
497757 49777' 497781 4977P
339 3N
lip
o
-
1 7T'T
C
b
V 4677
33°35N
L
Ir1ap niay not he valid at this
IV
33' 9'347'N
497757 467M5 497773 497781 467789 V
Map ScaIe:1:379pedonAndscape(11"x&5")ieet
N o 5 10 2D 3)
Feet 0 15 3) eD
9D A Map projedon: Web Mercator Corner coottiuiatee: WGS84 Edge tks: hIM Zone uN WGS84
USDA Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey
33° Sr 34N
37
C
1217/2018
Page 1 of 4
Hydrologic Soil Group—San Diego County Area, California
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres In AOl Percent of AOl
MIC Manna loamy coarse
sand, 2 to 9 percent
slopes
B 0.3 100.0%
Totals for Area of Interest 0.3 100.09A
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 (A/D, 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.
Rating Options
Aggregation Method: Dominant Condition
Natural Resources Web Soil Survey 12/7/2018 Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—San Diego County Area, California
Aggregation is the process by which a set of component attribute values is
reduced to a single value that represents the map unit as a whole.
A map unit is typically composed of one or more "components". A component is
either some type of soil or some nonsoil entity, e.g., rock outcrop. For the
attribute being aggregated, the first step of the aggregation process is to derive
one attribute value for each of a map unit's components. From this set of
component attributes, the next step of the aggregation process derives a single
value that represents the map unit as a whole. Once a single value for each map
unit is derived, a thematic map for soil map units can be rendered. Aggregation
must be done because, on any soil map, map units are delineated but
components are not.
For each of a map unit's components, a corresponding percent composition is
recorded. A percent composition of 60 indicates that the corresponding
component typically makes up approximately 60% of the map unit. Percent
composition is a critical factor in some, but not all, aggregation methods.
The aggregation method "Dominant Condition" first groups like attribute values
for the components in a map unit. For each group, percent composition is set to
the sum of the percent composition of all components participating in that group.
These groups now represent "conditions" rather than components. The attribute
value associated with the group with the highest cumulative percent composition
is returned. If more than one group shares the highest cumulative percent
composition, the corresponding "tie-break" rule determines which value should
be returned. The "tie-break" rule indicates whether the lower or higher group
value should be returned in the case of a percent composition tie. The result
returned by this aggregation method represents the dominant condition
throughout the map unit only when no tie has occurred.
Component Percent Cutoff. None Specified
Components whose percent composition is below the cutoff value will not be
considered. If no cutoff value is specified, all components in the database will be
considered. The data for some contrasting soils of minor extent may not be in the
database, and therefore are not considered.
Tie-break Rule: Higher
The tie-break rule indicates which value should be selected from a set of multiple
candidate values, or which value should be selected in the event of a percent
composition tie.
Natural Resources Web Soil Survey 12(7/2018 Conservation Service National Cooperative Soil Survey Page 4 of 4