HomeMy WebLinkAboutCT 03-01-03; LA COSTA RESORT & SPA PHASE 3; DRAINAGE STUDY; 2007-04-30HUNSAKER
^ASSOCIATES
SAN
PLANNING
ENCINEERING
SURVEYING
IRVINE
LOS ANGELES
RIVERSIDE
SAN DIEGO
ARIZONA
DRAINAGE STUDY
for
LA COSTA RESORT & SPA
PHASE 3
CT 03-01
City of Carlsbad, California
Prepared for:
Cameo Homes
1107 Quail Street
Newport Beach, CA 92660
W.o. 2534-3
April 30, 2007
Hunsaker & Associates
San Dlego, Inc.
DAVE HAMMAR
LEX WILLIMAN
ALISA VIALPANDO
DAN SMITH
RAY MARTIN
CHUCK CATER
9707 Waples Street
San Diego, CA 92121
(858) 558-4500 PH
(858) 558-1414 FX
www.HunsakerSD.com
lnfo@HunsakerSD,com
n o z
o
CL
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La Costa Resort & Spa Ptiase 3
Drainage Study
TABLE OF CONTENTS
SECTION
Chapter 1 - Executive Summary I
1.1 Introduction
1.2 Summary of Developed Condition
1.3 Summary of Results
1.4 References
Chapter 2 - Methodology & Model Development II
2.1 County of San Diego Drainage Design Criteria
2.2 Design Rainfall Determination
- 100-Year, 6-Hour Rainfall isopluvial Map
- 100-Year, 24-Hour Rainfall Isopluvial Map
2.3 Runoff Coefficient Determination
2.4 Rainfall Intensity Determination
- Urban Watershed Overland Time of Flow Nomograph
- Intensity-Duration Design Chart
- Gutter and Roadway Discharge-Velocity Chart
- Manning's Equation Nomograph
2.5 Model Development Summary
- Rational Method Hydrologic Analysis
Chapter 3 - 100-Year Hydrologic Model (AES Model Outputs) III
3.1 Developed Condition Analysis
Chapter 4 - Catch Basin Sizing IV
4.1 Catch Basin Sizing
Chapter 5 - Hydraulic Analysis V
5.1 STORM LEGEND
5.2 STORM Model Output
Chapter 6 - Hydrology Exhibits VI
6.1 Developed Condition Hydrology Exhibit
6.2 Master Hydroiogy Study Data
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La Costa Resort & Spa Phiase 3
Drainage Study
TABLE OF CONTENTS
SECTION
Chapter 1 - Executive Summary I
1.1 Introduction
1.2 Summary of Developed Condition
1.3 Summary of Results
1.4 References
Chapter 2 - Methodology & Model Development II
2.1 County of San Diego Drainage Design Criteria
2.2 Design Rainfall Determination
- 100-Year, 6-Hour Rainfall Isopluvial Map
- 100-Year, 24-Hour Rainfall Isopluvial Map
2.3 Runoff Coefficient Determination
2.4 Rainfall Intensity Detemnination
- Urban Watershed Overland Time of Flow Nomograph
- Intensity-Duration Design Chart
- Gutter and Roadway Discharge-Velocity Chart
- Manning's Equation Nomograph
2.5 Model Development Summary
- Rational Method Hydrologic Analysis
Chapter 3 - 100-Year Hydrologic Model (AES Model Outputs) III
3.1 Developed Condition Analysis
Chapter 4 - Catch Basin Sizing IV
4.1 Catch Basin Sizing
Chapter 5 - Hydraulic Analysis V
5.1 STORM LEGEND
5.2 STORM Model Output
Chapter 6 - Hydrology Exhibits VI
6.1 Developed Condition Hydroiogy Exhibit
6.2 Master Hydrology Study Data
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La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 1 - EXECUTIVE SUMMARY
1.1 - Introduction
The La Costa Resort & Spa project site is located southeast of the intersection of El
Camino Real and Arenal Road within the City of Carlsbad, California. The Phase 3
development lays on the northwest corner of the La Costa Resort & Spa project site
at the Arenal Road-El Camino Real intersection (see the Vicinity Maps below).
CITY OF OCEANSlOE
HCHHHf i^Ji
CITY OF VISTA
CITY OF
SAN MARCOS
CITY OF ENCINITAS
VICINITY MAP
NOT TO SCALE
J
PRCJECT
LOCATION VICINITYMAF
cm OF
SAN UARCOS
PROJECT
SITE
NTS
Runoff from the La Costa Resort & Spa site drains south into two (2) storm drains, a
24" and 36" storm drain, built within the adjacent El Camino Real Road. The outfalls
at El Camino Real have been designed by RBF Consulting per Drawing Nos.
422-6D and 422-6F.
This study analyzes developed condition 100-year peak flowrates for La Costa
Resort & Spa Phase 3 project site.
Since the site lies outside any FEMA fioodplain zones, Letters of Map Revision will
not be required. Treatment of storm water runoff from the site has been addressed
in a separate report - the "Stom? Water Management Plan for La Costa Resort-
Master Plan Amendment' dated October 29, 2003 by Rick Engineering Company.
Per City of Carlsbad drainage criteria, the Modified Rational Method should be used
to determine peak design flowrates when the contributing drainage area is less than
1.0 square mile. Since the total watershed area discharging from the site is less
than 1.0 square mile, the AES-2003 computer software was used to model the runoff
response per the Modified Rational Method. Methodology used for the computation
of design rainfall events, runoff coefficients, and rainfall intensity values are
consistent with criteria set forth in the "2003 County of San Diego Drainage Design
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La Costa Resort & Spa Ptiase 3
Drainage Study
Manual." A more detailed explanation of methodology used for this analysis is listed
in Chapter 2 of this report.
1.2 - Summarv of Developed Conditions
The La Costa Resort & Spa Phase 3 project proposes construction of resort villas,
commercial buildings and a parking structure.
This report analyzes the hydrologic impact from the proposed ultimate conditions for
the La Costa Resort & Spa Phase 3 development.
It must be noted that hydrologic impacts for the overall development of La Costa
Resort & Spa have been addressed in the "Drainage Study for La Costa Resort &
Spa" dated September 2006 by Hunsaker and Associates.
Runoff from the developed site is collected and conveyed southerly via one (1) storm
drain system within the project site, draining to a 12-inch storm drain. The 12-inch
storm drain then discharges into an existing 24-inch storm drain. This 24-inch storm
drain conveys flow in a southerly direction to a 36-inch storm drain adjacent to El
Camino Real. These flows then ultimately discharge to San Marcos Creek.
Per 2003 County of San Diego criteria, a runoff coefficient of 0.82 was assumed for
the proposed commercial areas to occupy the project site.
Peak flow rates listed below were generated based on criteria set forth in the "2003
San Diego County Hydrology Manuaf (methodology presented in Chapter 2 ofthis
report). Rational Method outputs are located in Chapter 3. Watershed delineations
and node locations are visually depicted on the hydrology exhibits, which are located
in the back pocket of this report.
TABLE 1 - Summary of Developed Conditions Peak Flows
Drainage Area (Ac) 100 Year Peak
Discharge (cfs)
Ultimate Developed
Condition 2.5 8.1
Per Master Drainage
Study * 2.5 8.1
Difference 0 0
"Refer to "Drainage Study for La Costa Resort & Spa dated September 2006".
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La Costa Resort & Spa Ptiase 3
Drainage Study
1.3 - Summarv of Results
The objective of this report is to analyze the peak flow rates from La Costa Resort &
Spa, Phase 3 in ultimate developed conditions.
Calculations showed that in ultimate developed conditions of Phase 3, there will be
no increase in peak flows as compared to the peak flows calculated in the "Drainage
Study of La Costa Resort & Spa" dated September 2006 by Hunsaker & Associates
San Diego, Inc.
For hydraulic analysis for the proposed storm drain systems, refer to "Drainage
Study of La Costa Resort & Spa dated September 2006 by Hunsaker & Associates
San Diego, Inc.
The onsite hydraulics is calculated in Chapter 5 ofthis report. The catch basin
sizing is calculated in Chapter 4 ofthis report.
1.4 - References
County of San Diego Design Hydrology Manual, June 2003
"Storm Water Management Plan for La Costa Resort & Spa Phase 11", Hunsaker &
Associates San Diego Inc., May 2005.
"Improvement Plans for La Costa Resort & Spa Costa Del Mar Entry", RBF
Consulting, March 2006.
"Storm Water Management Plan for La Costa Resort - Master Plan Amendment",
Rick Engineering Company, October 29, 2003.
"Preliminary Floodplain Hydraulic Analysis of San Marcos Creek and North
Tributary", RBF Consulting, August 2005.
"Drainage Study for La Costa Resort & Spa Phase", Hunsaker & Associates San
Diego Inc., September 2006.
"Storm Water Management Plan for La Costa Resort & Spa Phase 3", Hunsaker &
Associates San Diego Inc., January 2007.
La Costa Resort & Spa Exhibit (Included for Reference)
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. PROJECT
SITE
WATERSHED BOUNDARY
WATERSHED SUB-BOUNDARY
WATERSHED NODES (525
SUBAREA ACREAGE
FLOWLINE
LA COSTA RESORT & SPA
PHASE 3
CITY OF CARLSBAD, GALIFORNIA
SHEET
1
OF
1
La Costa Resort & Spa Ptiase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.1 - County of San Diego Drainage
Design Criteria
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SanDiego County Hydrology Manual Section: 2
Date: June 2003 " Page: 3 of 4
2.3 SELECTION OF HYDROLOGIC METHOD AND DESIGN CRTTERIA
Design Frequency - The flood frequency for determining the design storm discharge is
50 years for drainage that is upstream ofany major road-way and 100 years frequency for
all design storms at a major roadway, crossing the major roadway and thereafter. The
50-year storm flows shall be contained wdthin the pipe and not encroach into the travel
lane. For the 1 OO-year storm this includes allowing one lane of a four-lane road (four or
more lanes) to be used for conveyance without encroaching onto private property outside
the dedicated street right-of-way. Natural channels that remain natural -within private
property are excluded from the right-of-way guideline.
Design Method - The choice of method to determine flows (discharge) shall be based on
the size of the watershed area. For an area 0 to approximately 1 square mile the Rational
Method or the Modified Rational Method shall be used. For watershed areas larger than
1 square mile the NRCS hydrologic method shall be used. Please check with the
goveming agency for any variations to these guidelines.
2-3
San Diego County Hydrolosy Manual Section: 3
Date: June2003 " Page: lof26
SECTION 3
RA.TIONAL METHOD AND MODIFIED RATIONAL METHOD
3.1 THE RATIONAL METHOD
The Rational Method (RM) is a mathematical formula used to detemiine the maximum
runoff rate from a given rainfall. It has particular application in urban storm drainage, -ft'here
it is used to estimate peak runoff rates from small urban and rural watersheds for the design
of storm drains and small drainage structures. The RM is recommended for analyzing the
runofif response from drainage areas up to approximately 1 square mile in size. It should not
be used in instances where there is a junction of independent drainage systems or for
drainage areas greater than approximately 1 square mile in size. In these instances, the
Modified Rational Method (MRM) should be used for junctions of independent drainage
systems Ln watersheds up to approximately 1 square mile in size (see Section 3.4); or the
NRCS Hydrologic Method should be used for watersheds greater than approxunately 1
square mile in size (see Section 4).
The RM can be applied using any design storm frequency (e.g., 1 OO-year, 50-year, 10-year,
etc.). The local agency determines the design storm frequency that must be used based on
the type of project and specific local requirements. A discussion of design storm frequency
is provided in Section 2.3 of this manual. A procedure has been developed that converts the
6-hour and 24-hour precipitation isopluvial map data to an Intensity-Duration curve that can
be used for the rainfall intensity in the RM formula as sho-wn m Figure 3-1. The RM is
applicable to a 6-hour storm duration because the procedure uses Intensity-Duration Design
Charts that are based on a 6-hour storm duration.
3.1.1 Rational Method Formula
The RM formula estimates tlie peak rate of runoff at any location in a watershed as a fimction
of the drainage area (A), runoff coefficient (C), and rainfall intensity (1) for a duration equal
to the time of concentration (Tc), which is the time required for water to
3-1
San Diego County Hydrolosy Manual Section: 3
Date: June 2003 " Page: 3 of 26
flow from the most remote point of the basin to the location being analyzed. The RM
formula is expressed as follows:
Q = CIA
Where: Q = peak discharge, in cubic feet per second (cfs)
C = runoff coefficient, proportion of the rainfall that runs off the surface (no
units)
I = average rainfall intensity for a duration equal to the Tc for the area, in
inches per hour (Note: Ifthe computed Tc is less than 5 minutes, use 5
minutes for computing the peak discharge, Q)
A = drainage area contributing to the design location, in acres
Combining the units for the expression CIA yields:
1.008 cfs ''l acre X inch ^ f 43,560 ft'^ f I foot ^ f Ihour ^
^ hour j ^ acre ^ ^12 inches J ^3,600 seconds^
For practical purposes the unit conversion coefficient difference of 0.8% can be ignored.
The RM formula is based on The assumption that for constant rainfall intensity, the peak
discharge rate at a point will occur when the raindrop that falls at the most upstream point in
the tributary drainage basin arrives at the point of interest.
Unlike the MRM (discussed in Section 3.4) or the NRCS hydrologic method (discussed in
Section 4), the RM does not create hydrographs and therefore does not add separate subarea
hydrographs at collection points. Instead, the RM develops peak discharges in the main line
by increasing the Tc as flow travels downstream.
Characteristics of, or assumptions inherent to, the RM are listed below:
• The discharge flow rate resulting from any I is maximum when the I lasts as long as or
longer than the Tc.
3-3
San Diego County Hydroloay Manual Section: 3
Date: June 2003 " Page: 4 of 26
• The storm frequency of peak discharges is the same as that ofl for the given Tc.
• The fraction of rainfall that becomes runoff (or the runoff coefficient, C) is independent
of I or precipitation zone number (PZN) condition (PZN Condition is discussed in
Section 4.1.2.4).
• The peak rate of runoff is the only mfonnation produced by using the RM.
3.1.2 Runoff Coefficient
Table 3-1 lists the estimated runoff coefficients for urban areas. The concepts related to the
runoff coefficient were evaluated in a report entitled Evaluation, Rational Method "C"
Values (Hill, 2002) that was reviewed by the Hydrology Manual Committee. The Report is
available at San Diego County Department of Public Works, Flood Control Section and on
the San Diego County Department of Public Works web page.
The runoff coefficients are based on land use and soil type. Soil type can be determined from
the soil type map provided in Appendbc A. An appropriate runoff coefficient (C) for each
type of land use in the subarea should be selected from tiiis table and multiplied by tiie
percentage ofthe total area (A) included in that class. The sum ofthe products for all land
uses is the weighted runoff coefficient (i;[CA]). Good engineering judgment should be used
when applying the values presented in Table 3-1, as adjustments to these values may be
appropriate based on site-specific characteristics. In any event, the impervious percentage
(% Impervious) as given in the table, for any area, shall govem tiie selected value for C. The
runoff coefficient can also be calculated for an area based on soil type and impervious
percentage using the following formula:
3-4
San Dieao County Hydrology Manual Section: 3
Date: June 2003 " Page: 5 of 26
C = 0.90 X (% Impervious) + Cp x (1 - % Impervious)
Where: Cp = Pervious Coefficient Runoff Value for tiie soil type (sho-wn in
Table 3-1 as Undisturbed Natural Terrain/Permanent Open Space,
0% Impervious). Soil type can be deteimined from the soil type map
provided in Appendix A.
The values in Table 3-1 are typical for most urban areas. However, if the basin contains rural
or agricultural land use, parks, golf courses, or other types of nonurban land use that are
expected to be permanent, the appropriate value should be selected based upon the soil and
cover and approved by the local agency.
3-5
San Diego County Hydroloay Manual Section: 3
Date: June 2003 " Page: 7 of 26
3.1.3 Rainfall Intensity
The rainfall intensity (I) is the rainfall in inches per hour (in/hr) for a duration equal to the Tc
for a selected storai frequency. Once a particular storm frequency has been selected for
design and a Tc calculated for the drainage area, the rainfall intensity can be determined from
the Intensity-Duration Design Chart (Figure 3-1). The 6-hour storm rainfall amount (Pe) and
the 24-hour storm rainfall amount ^24) for the selected storm frequency are also needed for
calculation of I. Pe and P24 can be read from the isopluvial maps provided in Appendbc B.
An Intensity-Duration Design Chart applicable to all areas within San Diego County is
provided as Figure 3-1. Figure 3-2 provides an example of use of the Intensity-Duration
Design Chart. Intensity can also be calculated using the following equation:
I = 7.44P6D-°-''*'
Where: Pe = adjusted 6-hour storm rainfall amount (see discussion below)
D = duration in minutes (use Tc)
Note: This equation applies only to the 6-hour storm rainfall amount (i.e., P5 cannot be
changed to PiAto calculate a 24-hour iatensity using this equation).
The Intensity-Duration Design Chart and the equation are for tiie 6-hour storm rainfall
amount. In general, Pe for the selected frequency should be between 45% and 65% of P24 for
the selected frequency. If Pe is not witiiin 45% to 65% of P24, Pe should be increased or
decreased as necessary to meet this criteria. The isopluvial lines are based on precipitation
gauge data. At the time that tiie isopluvial lines were created, the majority of precipitation
gauges in San Diego County were read daily, and these readings yielded 24-hour
precipitation data. Some 6-hour data were available from tiie few recording gauges
distributed throughout tiie County at that time; however, some 6-hour data were extrapolated.
Therefore, the 24-hour precipitation data for San Diego County are considered to be more
reliable.
3-7
San Diego County Hydrology Manual Section: 3
Date: June 2003 Page: 9 of 26
3.1.4 Time of Concentration
The Time of Concentration (Tc) is the time required for mnoff to flow from the most remote
part of the drainage area to the point of interest. The Tc is composed of two components:
initial time of concentration (TO and travel time (Tt). Methods of computation for Ti and Tt
are discussed below. The Ti is the time required for runoff to travel across the surface ofthe
most remote subarea in the study, or "initial subarea." Guidelines for designating the initial
subarea are provided within the discussion of computation of Ti. The Tt is the time required
for the runoff to flow in a watercourse (e.g., swale, channel, gutter, pipe) or series of
watercourses from the initial subarea to the point of interest. For the RM, the Tc at any point
within the drainage area is given by:
Tc = Ti + Tt
Metiiods of calculation differ for natural watersheds (nonurbanized) and for urban drainage
systems. When analyzing storm drain systems, the designer must consider tiie possibility
that an existing natural watershed may become urbanized during the usefiil life ofthe storm
drain system. Future land uses must be used for Tc and runoff calculations, and can be
determined from the local Community General Plan.
3.1.4.1 Initial Time of Concentration
The initial time of concentration is typically based on sheet flow at the upstream end of a
drainage basin. The Overland Time of Flow (Figure 3-3) is approximated by an equation
developed by the Federal Aviation Agency (FAA) for analyzing flow on runaways (FAA,
1970). The usual mnway configuration consists of a crown, like most freeways, with sloping
pavement that directs flow to either side ofthe runway. This type of flow is uniform in the
direction perpendicular to the velocity and is very shallow. Since these depths are 14 of an
inch (more or less) in magnitude, the relative roughness is high. Some higher relative
rouglmess values for overland flow are presented in Table 3.5 of the HEC-1 Flood
Hydrograph Package User's Manual (USAGE, 1990).
3-9
San Diego County Hydroloay Manual Section: 3
Date: June 2003 " Page: 11 of 26
The sheet flow that is predicted by the FAA equation is limited to conditions that are similar
to runway topography. Some considerations that limit the extent to which the FAA equation
applies are identified below:
• Urban Areas - This "runway type" runoff includes:
1) Flat roofs, sloping at 1% ±
2) Parking lots at the extreme upstream drainage basin bovmdary (at the "ridge" of a
catchment area).
Even a parking lot is limited in the amounts of sheet flow. Parked or moving
vehicles would "break-up" the sheet flow, concentrating runoff into streams that
are not characteristic of sheet flow.
3) Driveways are constmcted at the upstream end of catchment areas in some
developments. However, if flow from a roof is directed to a driveway through
a do-wnspout or other conveyance mechanism, flow would be concentrated.
4) Flat slopes are prone to meandering flow that tends to be dismpted by minor
irregularities and obstmctions. Maximum Overland Flow lengths are shorter
for the flatter slopes (see Table 3-2).
• Rural or Natural Areas - The FAA equation is applicable to these conditions since
(.5% to 10%) slopes that are uniform in width of flow have slow velocities consistent
with the equation. Irregularities in terrain limit the length of application.
1) Most hills and ridge lines have a relatively flat area near the drauiage divide.
However, with flat slopes of .5% ±, minor irregularities would cause flow to
concentrate into streams.
2) Parks, lawns and other vegetated areas would have slow velocities that are
consistent -with the FAA Equation.
The concepts related to the initial time of concentration were evaluated m a report entitled
Imtial Time of Concenti-ation, Analysis of Parameteis (Hill, 2002) that was reviewed by tiie
Hydrology Manual Committee. The Report is available at San Diego County Department of
Public Works, Flood Confrol Section and on the San Diego County Department of Public
Works web page.
3-11
San Diego County Hydrology Manual
Date: June 2003
Section:
Paae: 12 of 26
Note that the Initial Time of Concentration should be reflective of the general land-use at tiie
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 Tj values based on average C values for the Land Use Element are
also included. These values can be used in plannuig and design applications as described
below. Exceptions may be approved by the "Regulating Agency" when submitted with a
detailed study.
Table 3-2
MAXIMUM OVERLAM) FLOW LENGTH (LM)
& INITIAL TIME OF CONCENTRATION (Tj)
Element* DU/ .5% 1% 2% 3% 5% 10%
Acre LM Ti LM Ti LM Ti LM Ti LM Ti LM Ti
Natural 50 13.2 70 12.5 85 10.9 100 10.3 100 8.7 100 6.9
LDR 1 50 12.2 70 11.5 85 10.0 100 9.5 100 8.0 100 6.4
LDR 2 50 11.3 70 10.5 85 9.2 100 8.8 100 7.4 100 5.8
LDR 2.9 50 10.7 70 10.0 85 8.8 95 8.1 100 7.0 100 5.6
MDR 4.'3 50 10.2 70 9.6 80 8.1 95 7.8 100 6.7 100 5.3
MDR 7.3 50 9.2 65 8.4 80 7.4 95 7.0 100 6.0 100 4.8
MDR 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 5.4 100 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 4.0 85 3.8 95 3.4 100 2.7
N. Com 50 5.3 60 4.5 75 4.0 85 3.8 95 3.4 100 2.7
G. Com 50 4.7 60 4.1 75 3.6 85 3.4 90 2.9 100 2.4
O.P./Com 50 4.2 60 3.7 70 3.1 80 2.9 90 2.6 100 2.2
Limited I. 50 4.2 60 3.7 70 3.1 80 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
3-12
San Diego County Hydrology Manual Section: 3
Date: June 2003 Page: 13 of 26
3.1.4.1A Planning Considerations
The purpose of most hydrology studies is to develop flood flow values for areas that are not
at the upstream end of the basin. Another example is the Master Plan, which is usually
completed before the actual detailed design of lots, streets, etc. are accomplished. In these
situations it is necessary that the initial time of concentration be detemiined without detailed
information about flow pattems.
To provide guidance for the initial time of concentration design parameters. Table 3-2
includes the Land Use Elements and other variables related to the Time of Concenfration.
The table development included a review of the typical "layout" of the different Land Use
Elements and related flow pattems and consideration oftiie extent of the sheet flow regimen,
the effect of ponding, the significance to the drainage basin, downsfream effects, etc.
3.1.4.1B Computation Criteria
(a) Developed Drainage Areas With Overland Flow - Ti may be obtained directiy from the
chart, "Rational Fonnula - Overland Time of Flow Nomograph," sho-wn in Figure 3-3
or from Table 3-2. This chart is based on the Federal Aviation Agency (FAA) equation
(FAA, 1970). For the short rain durations (<15 minutes) involved, intensities are high
but the depth of flooding is limited and much of the mnoff is stored temporarily in the
overland flow and in shallow ponded areas. In developed areas, overland flow is
limited to lengths given in Table 3-2. Beyond these distances, flow tends to become
concentrated into streets, gutters, swales, ditches, etc.
3-13
San Diego County Hydrology Manual Section: 3
Date: June 2003 " Page: 14 of 26
(b) Natural Or Rural Watersheds - These areas usually have an initial subarea at the
upstream end with sheet flow. The sheet flow length is limited to 50 to 100 feet as
specified in Table 3-2. The Overland Time of Flow Nomograph, Figure 3-3, can be
used to obtain Ti. The initial time of concentration can excessively affect tiie
magnitude of flow further downstream in the drainage basin. For instance, variations
in the initial time of concentration for an initial subarea of one acre can change the
flow further do-wnsfream where the area is 400 acres by 100%. Therefore, the initial
time of concenfration is limited (see Table 3-2).
The Rational Method procedure included in tiie original Hydrology Manual (1971) and
Design and Procedure Manual (1968) included a 10 minute value to be added to the initial
time of concenfration developed through the Kirpich Formula (see Figure 3-4) for a natural
watershed. That procedure is superceded by the procedure above to use Table 3-2 or Figure
3-3 to determine Ti for the appropriate sheet flow length ofthe initial subarea. The values for
natural watersheds given in Table 3-2 vary from 13 to 7 minutes, dependmg on slope. If the
total length of the initial subarea is greater than the maximum length allowable based on
Table 3-2, add the fravel time based on the Kirpich formula for the remaining length of the
initial subarea.
3.1.4.2 Travel Time
The Tt is the time requtred for the runoff to fiow in a watercourse (e.g., swale, channel,
gutter, pipe) or series of watercourses from the initial subarea to the point of interest. The Tt
is computed by dividing the length of the flow path by the computed flow velocity. Since the
velocity normally changes as a result of each change in flow rate or slope, such as at an inlet
or grade break, the total Tt m-ust be computed as the sum ofthe Tt's for each section of the
flow path. Use Figure 3-6 to estimate time of travel for sfreet gutter flow. Velocity in a
channel can be estimated by using the nomograph sho-wn Ln Figure 3-7 (Manning's Equation
Nomograph).
3-14
San Diego County Hydroloay Manual Section: 3
Date: June 2003 " Page: 15 of 26
(a) Natural Watersheds - This includes mral, ranch, and agricultural areas with natural
channels. Obtain Tt directly from the Kirpich nomograph in Figure 3-4 or from the
equation. This nomograph requires values for length and change in elevation along
the effective slope line for the subarea. See Figure 3-5 for a representation of the
effective slope line.
This nomograph is based on die Kirpich formula, which was developed with data
from agricultural watersheds ranging from 1.25 to 112 acres in area, 350 to 4,000 feet
m lengtii, and 2.7 to 8.8% slope (Kirpich, 1940). A maximum lengtii of 4,000 feet
should be used for the subarea length. Typically, as the flow lengtii increases, the
deptii of flow will increase, and therefore it is considered a concenfration of flow at
points beyond lengths listed in Figure 3-2. However, because the Kirpich formula
has been shown to be applicable for watersheds up to 4,000 feet in length (ICiipich,
1940), a subarea may be designated -with a length up to 4,000 feet provided the
topography and slope ofthe natural channel are generally uiuform.
Justification needs to be included with this calculation showing that the watershed
will remain natural forever. Examples include areas located in the Multiple Species
Conservation Plan (MSCP), areas designated as open space or rural ui a community's
General Plan, and Cleveland National Forest.
(b) Urban Watersheds - Flow through a closed conduit where no additional flow can enter the
system during the travel, length, velocity and Tt are determined using the peak flow in
the conduit. In cases where the conduit is not closed and additional flow from a
contributing subarea is added to the total flow during travel (e.g., street flow in a
gutter), calculation of velocity and Tt is performed using an assumed average flow
based on the total area (including upstream subareas) contributing to the point of
mterest. The Manning equation is usually used to determine velocity. Discharges for
small watersheds typically range from 2 to 3 cfs per acre, depending on land use,
drainage area, and slope and rainfall intensity.
Note: The MRM should be used to calculate the peak discharge when there is a junction
from independent subareas into the drainage system.
3-15
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.2 - Design Rainfall Determination
100-Year, 6-Hour Rainfall Isopluvial Map
DG:mj h:\reports\2534\03\a03.doc
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County of San Diego
Hydrology Manual
Rainfall Isopluvials
100 Year Rainfall Event - 6 Hours
Isopluvial (Inches)
1 lOHjfc
DPW ^GIS GIS
THS li'AP IS PROVIOEP WITHOUT VIUVWiTf Of MIY KIND. SfTHER EXPRESS OA eiffum. WKLiOMa. BUT KOT UMITED TO. THE HAJED VIAIWUmS or i'ERCHWTABHJTV ANO '•ITMESS FOn A PARTICUlAn PUHPOK.
32*30'
^ mfomMnnSt
3 0 3 Miles
nUa SANDAORij'giHl
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.2 - Design Rainfall Determination
100-Year, 24-Hour Rainfall Isopluvial Map
•G:mj h:\reports\2534\03\a03.cloc
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33'30' 33'30'
33W
32*45'
County of San Diego
Hydrology Manual
Rainfall Isopluvials
100 Year Rainfall Event - 24 Hours
Isopluvial (inches)
I (OOl '
DPW
TINS fAP 19 PROVKIED WITHOUT VfARFWITY DF PtK KMO. EITHER GJIPREBS on MPUCP KCLUDtJO BUT NOT UMITED TO. THE KtPUED WARRAMTIES Of veRCHANTABIlJTY AM) nTKESS FOR A PARTICULAR PURPOS
Qnn^n >*«IS. Al RigNi RtMnd.
3 Miles
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.3 - Runoff Coefficient Determination
DG:mj h:\reports\2534^3\a03.doc
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San Diego County Hydrology Manual
Date: June 2003
Seclion:
Page:
3
6 of 26
Table 3-1
RUNOFF COEFFICIENTS FOR URBAN AREAS
Land Use Rimoff Coerricient "C"
Soil Type
NRCS Elements Counly Elements % IMPER. A B C D
Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 0.30 0.35
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) Residenlial, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52
Mediuni Density Residential (MDR) Residenlial, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57
Medium Density Residential (MDR) Residenlial, 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) Residenlial, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71
High Density Residenlial (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 0.79
Coininercial/liiduslrial (N. Coin) Neighborhood Commercial 80 0.76 0.77 0.78 0.79
Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 0.81 0.82
Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (Limited L) Limiled Industrial 90 0.83 0.84 0.84 0.85
Commercial/Industrial (General 1.) General Industrial 95 0.87 0.87 0.87 0.87
•The values associaied wilh 0% impervious may bc used for direct calculation ot the runolt coerticient as acscrmea in section ^rcpicii;.iu..K u.u |,U.VK,U.-, .unu..
coefficiem, Cp, Ibr the soil type), or for areas lhat will remain undisturbed in perpetuity. Justification must be given that the area will remain natural (orcvcr (e.g., the area
is located in Cleveland National Forest).
DU/A = dwelling units per acre
NRCS = Nalional Resources Conservation Service
3-6
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.4 - Rainfall Intensity Determination
Urban Watershed Overland Time of Flow
Nomograph
DG:mj h:\reports\2534\03\a03.doc
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100
UJ O z
D UJ CO
tr. o o a:
Ul
i
EXAMPLE:
Given: Watercourse Dislance (D) = 70 Feel
Slopo (0) =1.3%
Runoff Coefficient (C) = 0.41
Overland Flow/ Time (T) = 9.5 Minutes
SOURCE: Airport Drainage, Federal Aviation Administration, 1965
1.8 (1.1-C) Vb
F I G U U E
Rational Formula - Overland Time of Flow Nomograph
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.4 - Rainfall Intensity Determination
Intensity-Duration Design Chart
DG:mj h:\reports\2534\03\a03.doc
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7 8 9 10 20 30 40 50 1 Minutes
Duraiion
Olrections for Application:
(1) From precipitation maps delemiine 6 hr and 24 hr amounts
for the selected frequency. These maps are included in the
County Hydrology Manual (10,50, and 100 yr maps included
in the Design and Procedure IVIanual).
(2) Adjust 6 hr precipilatlon (if necessary) so that it Is within
the range of 45% to 65% of the 24 hr precipitation (not
applicaple to Desert).
(3) Plot 6 hr precipitation on the right side of the chart.
(4) Draw a line through the point parallel to fhe plotted lines.
(5) This line Is the intensity-duration curve for the location
being analyzed.
. year
-1^ = %<2) •P 24
Application Form:
(a) Selected frequency
(b) P6= in., P24 =
(c) Adjusted Pg'^) =
(d) tjj = min.
(e) I = in./hr.
Note: This chart replaces the Intensity-Duration-Frequency
curves used since 1965.
PC
Durntion
" 1
1
1.5
r T :-2;s:
1
3' • i 3.5
4"
1 ' f •
S.S
1 i
5 2.U3 3 951b 2/ Ct 59 7.00 0 22 10.54 11.86 13.17 14.49 15.01
7 2:12 3.1B{4.24 5.30 6 36 /'42 8.48 9.54 10.60 11 66 12.-/2
10 1.(58 2.5313.37 4.21 5.05 5.80 6.74 /.58 B.42 9 27 10.11
15 1.30 1.95 2.59 3.24 3.89 4.5-1 5.19 5.04 0.49 713 7.78
2 b 1.00 1.62 2.15 2 6913 23 3 7/ 4.31 4.85 5.39 5.93 6.46
25 0.93 1.40 1.8/ 2.33 2U0 3 2/1 3 /J 4.20 4.67 5.13 S.60
30 0,B3 1.24 1.66 2.07 2.4912.90 3.32 J /3 4.15 4.56 4.00
40 0.69 1.03 1.38 1.72 2.07 2.41 2.76 3.10 3.45 3.79 4.13
50 0.00 0.90 1.19 1.49 1 79 2.09 2.39 2.69 2.98 3.28 3.58
CO 0.53 10.80 LOG 1.33 1 59 1.00 2.12 2.39 2.6S 2.92 3.10
90 0.41 0.61 0.82! 1.02 1.231 1.43 1.63 1.84 2.04 2.25 2.45
0.34 051 0.60 0.05 1.02 1.19 1.36 1.53 1.70 1.07 2.04
ISO 0.29 0.44 0.59 0.73 0.80 1.03 1.10 1.32 1.47 1.62 1.70
160 6.26 0.39 0.62 0.65 0.78 0.91 1.04 1.10 1.31 1.44 1.57
240 0.22 0.33 0.43 0.54 O.GS 0.7G 0.87 0.98 1.00 1.19 1.30
300 0.10 0.28 0.38 0.47 0.5610.00 0.75 0.85 0.94 1.03 1.13
360 0.17 0 25 0 33 0.42 i 0.50 0.58' 0.6/ 0.75 0.84 0.92 1.00
F 1 G U R E
Intensity-Duration Design Chart - Template
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.4 - Rainfall Intensity Determination
Gutter and Roadway Discharge-Velocity Chart
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1 2 3 456789 10
Discharge (C.F.S.)
EXAMPLE:
Given: Q = 10 S = 2.5%
Chart gives: Depth = 0.4, Velocity = 4.4 f.p.s.
SOURCE: San Diego County Department of Special District Serwces Design Manual
30 40 50
Gutter and Roadway Discharge - Velocity Chart
FIGURE
La Costa Resort & Spa, Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.4 - Rainfall Intensity Determination
Manning's Equation Nomograph
RArDE h:\repo(ts\2534«X13\a01 doc
w.o. 2503-1 1/23/2007 1:2B PM
-0.3
.0.2
UJ
CL O _l CO
EQUATION: V = 1.49 R^J S"2 n
0.2
•0.15
0.10
0.09
0.08
0.07
0.06
0.05
0.03
0.02
0.01
0.009
O.OOB
0.007
0.006
0.005
0.004^^^
r 0.003
0.002
0.001
0.0009
0.0008
0.0007
0.0006
- 0.0005
C 0.0003
-0.3
0.4
E
-0.5
0.6
:0T^
,0.8
rO.9
i.1.0
:3-^
i-4
5
6
7
8
9
10
1-20
SOURCE: USDOT, FHWA, HDS-3 (1961)
GENERAL SOLUTION
£.50
i
r
I t
•20
rio
O u 0) m
a.
(U
•3
>
r-0.01
^0;
•0.02
-0.03
c S "o £ a> o O CO
CO UJ z
I o
o cc
E-0.04
rO.05
.0.06
-0.07
1-0.09
-0.10
•1.0
• 0.9
•0.8
•0.7
^0.5
-0.3
-0.4
FIGURE
Manning's Equation Nomograph
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 2
METHODOLOGY & MODEL DEVELOPMENT
2.5 - Model Development Summary
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La Costa Resort & Spa Phase 3
Drainage Study
Rational Method Hvdrologv Analvsis
Computer Software Package - AES-2003
Design Storm - 100-Year Return Interval
Land Use - Commercial and Residential
Soil Type - Hydrologic soii group D was assumed for all areas. Group D soils have
very slow infiltration rates when thoroughly wetted. Consisting chiefly of clay soils
with a high swelling potential, soils with a high permanent water table, soils with clay
pan or clay layer at or near the surface, and shallow soils over nearly impervious
materials, Group D soils have a very slow rate of water transmission.
Runoff Coefficient - In accordance with the County of San Diego standards,
commercial areas were assigned a runoff coefficient of 0.82, residential areas were
designated a runoff coefficient of 0.52, and areas that are 90% impervious were
assigned a runoff coefficient of 0.87.
Method of Analysis - The Rational Method is the most widely used hydrologic model
for estimating peak runoff rates. Applied to small urban and semi-urban areas with
drainage areas less than 0.5 square miles, the Rational Method relates storm rainfall
intensity, a runoff coefficient, and drainage area to peak runoff rate. This
relationship is expressed by the equation:
Q = CIA, where:
Q = The peak runoff rate in cubic feet per second at the point of analysis.
C = A runoff coefficient representing the area - averaged ratio of runoff to rainfall
intensity.
I = The time-averaged rainfall intensity in inches per hour corresponding to the
time of concentration.
A = The drainage basin area in acres.
To perform a node-link study, the total watershed area is divided into subareas
which discharge at designated nodes.
The procedure for the subarea summation model is as follows:
(1) Subdivide the watershed into an initial subarea (generally 1 lot) and
subsequent subareas, which are generally less than 10 acres in size. Assign
upstream and downstream node numbers to each subarea.
(2) Estimate an initial Tc by using the appropriate nomograph or overland flow
velocity estimation.
(3) Using the initial Tc, determine the corresponding values of I. Then Q = C I A.
DG:mj h:\reports\2534\03\a03.doc
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La Costa Resort & Spa Phase 3
Drainage Study
(4) Using Q, estimate the travel time between this node and the next by
Manning's equation as applied to the particular channel or conduit linking the
two nodes. Then, repeat the calculation for Q based on the revised intensity
(which is a function of the revised time of concentration)
The nodes are joined together by links, which may be street gutter flows, drainage
swales, drainage ditches, pipe flow, or various channel flows. The AES-99 computer
subarea menu is as follows:
SUBAREA HYDROLOGIC PROCESS
1. Confluence analysis at node.
2. Initial subarea analysis (including time of concentration calculation).
3. Pipeflow travel time (computer estimated).
4. Pipeflow travel time (user specified).
5. Trapezoidal channel travel time.
6. Street flow analysis through subarea.
7. User - specified information at node.
8. Addition of subarea runoff to main line.
9. V-gutter flow through area.
10. Copy main stream data to memory bank
11. Confluence main stream data with a memory bank
12. Clear a memory bank
At the confluence point of two or more basins, the following procedure is used to
combine peak flow rates to account for differences in the basin's times of
concentration. This adjustment is based on the assumption that each basin's
hydrographs are triangular in shape.
1. If the collection streams have the same times of concentration, then the Q
values are directly summed,
Qp = Qa + Qb; Tp = Ta = Tb
2. If the collection streams have different times of concentration, the smaller of the
tributary Q values may be adjusted as follows:
a. The most frequent case is where the collection stream with the longer time
of concentration has the larger Q. The smaller Q value is adjusted by the
ratio of rainfall intensities.
Qp = Qa + Qb (la/lb); Tp = Ta
DG:mj h:\reports\2534\03\a03.doc
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La Costa Resort & Spa Phase 3
Drainage Study
b. In some cases, the collection stream with the shorter time of concentration
has the larger Q. Then the smaller Q is adjusted by a ratio of the T
values.
Qp = Qb + Qa (Tb/Ta); Tp = Tb
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La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 3
DEVELOPED CONITION 100-YEAR
HYDROLOGIC MODEL FOR
PHASE 3
(AES MODEL OUTPUTS)
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***i.************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2003 Acivanced Engineering Software (aes)
Ver. l.SA Release Date: 01/01/2003 License ID 1239
Ajialysis prepared by:
HUNS-AKER & ASSOCIATES - SAN DIEGO
10179 Huennekens Street
San Diego, Ca. 92121
(858) 558-4500
•*•*•**•*•***•*•*****•*••****•*•*•****•* DESCRIPTION OF STUDY ********************************
* LA COSTA RESORT & SPA H&A W0# 2534-03 *
* 100 YEAR DE-VELOPED CONDITION HYDROLOGIC ANALYSIS *
* JANUARY 22, 2007 *
**************************************************************************
FILE NAME: H:\AES2003\2534\3\DEV100.DAT
TIME/DATE OF STUDY: 17:18 01/22/2007
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM E-VENT{YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.750
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS (DECIM.AL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
+ -I-
I START OF SITE FLOW TO NODE 522 |
+ --f
****************************************************************************
FLOW PROCESS FROM NODE 520.00 TO NODE 521.00 IS CODE = 21
>>>>>RATIONAL METHOD INITIAL SUBAREA AJSrALYSIS<<<<<
GENEPJUJ COMMERCIAL RUNOFF COEFFICIENT = .8200
SOIL CLASSIFICATION IS "D"
S.C.S. CUR'VE NUMBER (AMC II) = 95
INITIAL SUBAREA FLOW-LENGTH(FEET) = 70.00
UPSTREAM ELEVATION(FEET) = 76.00
DOWNSTREAM ELEVATION(FEET) = 75.00
ELEVATION DIFFERENCE(FEET) = 1.00
SUBAREA OVERLAND TIME OF FLOW(MIN.) = 3.647
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM 0-VERLAND FLOW LENGTH = 66.43
(Reference: Table 3-lB of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.246
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.
SUBAREA RUNOFF(CFS) = 0.59
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.59
****************************************************************************
FLOW PROCESS FROM NODE 521.00 TO NODE 522.00 IS CODE = 52
»>»COMPUTE NATURAL VALLEY CHANNEL FLOW<<<<<
»»>TRA'VELTIME THRU SUBAREA<<<<<
ELEVATION DATA: UPSTREAM(FEET) = 75.00 DOWNSTREAM(FEET) = 67.80
CHAJWEL LENGTH THRU SUBAREA (FEET) = 780.00 CHANNEL SLOPE = 0.0092
NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN -VELOCITY ESTIMATION
CHANNEL FLOW THRU SUBAREA(CFS) = 0.59
FLOW VELOCITY(FEET/SEC) = 1.44 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL)
TRAVEL TIME(MIN.) = 9.02 Tc(MIN.) = 12.67
LONGEST FLOWPATH FROM NODE 520.00 TO NODE 522.00 = 850.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 521.00 TO NODE 522.00 IS CODE = 81
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.97 8
GENERAL COMMERCIAL RUNOFF COEFFICIENT = .8200
SOIL CLASSIFICATION IS "D"
S.C.S. CURVE NUMBER (AMC II) = 95
AREA-AVERAGE RUNOFF COEFFICIENT = 0.8200
SUBAREA AREA(ACRES) = 2.40 SUBAREA RUNOFF(CFS) = 7.83
TOTAL AREA(ACRES) = 2.50 TOTAL RUNOFF(CFS) = 8.15
TC(MIN.) =12.67
END OF SITE FLOW TO NODE 522
-I-- +
+ +
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 2.50 TC(MIN.) = 12.67
PEAK FLOW RATE(CFS) = 8.15
END OF RATIONAL METHOD ANALYSIS
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 4
CATCH BASIN SIZING
DG:mj h:\repor1s\2534\03\a03.doc
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La Costa Villas
Area Calcs
Project Name: LA COSTA VILLAS
Date: 4/25/2007
Description: Catch Basin Area Calculations
Total Area = 2.5 Acres
Total Flow = 8.1 CFS
Catch Basin Area to CB
(Acres)
Flow to CB
(cfs)
1 0.1 0.32 Example:
2 0.1 0.32
3 0.1 0.32 Total Area
4 0.2 0.65 Total Flow
5 0.1 0.32
6 0.1 0.32 2.5
7 0.2 0.65 8.1
8 1.6 5.2
Area to CB
Flow to CB
0.1
x= 0.32 cfs
Date; 4/25/2007 File: Drainage Area Calcs.xis Page 1 of 1
KNOWN:
Node 1
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
Design Flow, Q = 0.32 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L= 3'-4"= 3.33 ft
Width, W= r-11 %"= 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
ORIFICE EQUATION:
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H>= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
1/2 Q = CA(2gH)
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Single "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 5.3 0.6 6.56 1.33 14.13
0.4 3.33 1.97 2.92 5.3 0.6 3.28 3.92 9.99
0.6 3.33 1.97 3.08 5.3 0.6 3.28 7.59 12.23
0.8 3.33 1.97 3.30 5.3 0.6 3.28 12.51 14.13
1.0 3.33 1.97 3.32 5.3 0.6 3.28 17.60 15.79
1.2 3.33 1.97 3.32 5.3 0.6 3.28 23.13 17.30
1.4 3.33 1.97 3.32 5.3 0.6 3.28 29.15 18.69
1.6 3.33 1.97 3.32 5.3 0.6 3.28 35.61 19.98
1.8 3.33 1.97 3.32 5.3 0.6 3.28 42.49 21.19
2.0 3.33 1.97 3.32 5.3 0.6 3.28 49.77 22.34
2.2 3.33 1.97 3.32 5.3 0.6 3.28 57.42 23.43
2.4 3.33 1.97 3.32 5.3 0.6 3.28 65.42 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orlfice vs Weir.xis
KNOWN:
Node 2
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
Design Flow, Q =0.32 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L = 3' - 4" = 3.33 ft
Width, W= 1'-11 %"= 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
ORIFICE EQUATION:
Q = CA(2gH)^'^
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Single "G-I" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 5.3 0.6 6.56 1.33 14.13
0.4 3.33 1.97 2.92 5.3 0.6 3.28 3.92 9.99
0.6 3.33 1.97 3.08 5.3 0.6 3.28 7.59 12.23
0.8 3.33 1.97 3.30 5.3 0.6 3.28 12.51 14.13
1.0 3.33 1.97 3.32 5.3 0.6 3.28 17.60 15.79
1.2 3.33 1.97 3.32 5.3 0.6 3.28 23.13 17.30
1.4 3.33 1.97 3.32 5.3 0.6 3.28 29.15 18.69
1.6 3.33 1.97 3.32 5.3 0.6 3.28 35.61 19.98
1.8 3.33 1.97 3.32 5.3 0.6 3.28 42.49 21.19
2.0 3.33 1.97 3.32 5.3 0.6 3.28 49.77 22.34
2.2 3.33 1.97 3.32 5.3 0.6 3.28 57.42 23.43
2.4 3.33 1.97 3.32 5.3 0.6 3.28 65.42 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 Of 2 H:\EXCEL\2534\03\TYPE G CB-Orifice vs Weir.xis
KNOWN:
Node 3 Design Flow, Q =0.32 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L = 3' - 4" = 3.33 ft
Width, W = 1'-11 %"= 1.97 ft
WEIR EQUATION:
Q = CLH 3/2
where: C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
ORIFICE EQUATION:
Q = CA(2gH) 1/2
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Single "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 5.3 0.6 6.56 1.33 14.13
0.4 3.33 1.97 2.92 5.3 0.6 3.28 3.92 9.99
0.6 3.33 1.97 3.08 5.3 0.6 3.28 7.59 12.23
0.8 3.33 1.97 3.30 5.3 0.6 3.28 12.51 14.13
1.0 3.33 1.97 3.32 5.3 0.6 3.28 17.60 15.79
1.2 3.33 1.97 3.32 5.3 0.6 3.28 23.13 17.30
1.4 3.33 1.97 3.32 5.3 0.6 3.28 29.15 18.69
1.6 3.33 1.97 3.32 5.3 0.6 3.28 35.61 19.98
1.8 3.33 1.97 3.32 5.3 0.6 3.28 42.49 21.19
2.0 3.33 1.97 3.32 5.3 0.6 3.28 49.77 22.34
2.2 3.33 1.97 3.32 5.3 0.6 3.28 57.42 23.43
2.4 3.33 1.97 3.32 5.3 0.6 3.28 65.42 24.47
*NOTE: Assumes 50% clogging.
KNOWN:
Node 4
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
Design Flow, Q = 0.65 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L = 3' - 4" = 3.33 ft
Width, W= 1'-11 %"= 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H>= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
ORIFICE EQUATION:
1/2 Q = CA(2gH)
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Singie "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 5.3 0.6 6.56 1.33 14.13
0.4 3.33 1.97 2.92 5.3 0.6 3.28 3.92 9.99
0.6 3.33 1.97 3.08 5.3 0.6 3.28 7.59 12.23
0.8 3.33 1.97 3.30 5.3 0.6 3.28 12.51 14.13
1.0 3.33 1.97 3.32 5.3 0.6 3.28 17.60 15.79
1.2 3.33 1.97 3.32 5.3 0.6 3.28 23.13 17.30
1.4 3.33 1.97 3.32 5.3 0.6 3.28 29.15 18.69
1.6 3.33 1.97 3.32 5.3 0.6 3.28 35.61 19.98
1.8 3.33 1.97 3.32 5.3 0.6 3.28 42.49 21.19
2.0 3.33 1.97 3.32 5.3 0.6 3.28 49.77 22.34
2.2 3.33 1.97 3.32 5.3 0.6 3.28 57.42 23.43
2.4 3.33 1.97 3.32 5.3 0.6 3.28 65.42 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orifice vs Weir.xis
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
KNOWN:
Node 5 Design Flow, Q = 0.32 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L = 3' - 4" = 3.33 ft
Width, W= 1'-11 le 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
ORIFICE EQUATION:
Q = CA(2gH)^'^
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Single "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 7.27 0.6 6.56 1.82 14.13
0.4 3.33 1.97 2.92 7.27 0.6 3.28 5.37 9.99
0.6 3.33 1.97 3.08 7.27 0.6 3.28 10.41 12.23
0.8 3.33 1.97 3.30 7.27 0.6 3.28 17.17 14.13
1.0 3.33 1.97 3.32 7.27 0.6 3.28 24.14 15.79
1.2 3.33 1.97 3.32 7.27 0.6 3.28 31.73 17.30
1.4 3.33 1.97 3.32 7.27 0.6 3.28 39.98 18.69
1.6 3.33 1.97 3.32 7.27 0.6 3.28 48.85 19.98
1.8 3.33 1.97 3.32 7.27 0.6 3.28 58.29 21.19
2.0 3.33 1.97 3.32 7.27 0.6 3.28 68.27 22.34
2.2 3.33 1.97 3.32 7.27 0.6 3.28 78.76 23.43
2.4 3.33 1.97 3.32 7.27 0.6 3.28 89.74 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orifice vs Weir.xis
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
KNOWN:
Node 6 Design Flow, 0 = 0.32 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L= 3'-4"= 3.33 ft
Width, W= 1'-11 %"= 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
ORIFICE EQUATION:
Q = CA(2gH)"^
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Single "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 5.3 0.6 6.56 1.33 14.13
0.4 3.33 1.97 2.92 5.3 0.6 3.28 3.92 9.99
0.6 3.33 1.97 3.08 5.3 0.6 3.28 7.59 12.23
0.8 3.33 1.97 3.30 5.3 0.6 3.28 12.51 14.13
1.0 3.33 1.97 3.32 5.3 0.6 3.28 17.60 15.79
1.2 3.33 1.97 3.32 5.3 0.6 3.28 23.13 17.30
1.4 3.33 1.97 3.32 5.3 0.6 3.28 29.15 18.69
1.6 3.33 1.97 3.32 5.3 0.6 3.28 35.61 19.98
1.8 3.33 1.97 3.32 5.3 0.6 3.28 42.49 21.19
2.0 3.33 1.97 3.32 5.3 0.6 3.28 49.77 22.34
2.2 3.33 1.97 3.32 5.3 0.6 3.28 57.42 23.43
2.4 3.33 1.97 3.32 5.3 0.6 3.28 65.42 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orlfice vs Weir.xis
KNOWN:
Node 7
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
Design Flow, Q = 0.65 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L= 3'-4"= 3.33 ft
Width, W= 1'-11 78"= 1.97 ft
WEIR EQUATION:
Q = CLH
where:
3/2
ORIFICE EQUATION:
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
1/2 Q = CA(2gH)
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Calculations for Catch Basin Type "G" - Singie "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 10.6 0.6 6.56 2.65 14.13
0.4 3.33 1.97 2.92 10.6 0.6 3.28 7.83 9.99
0.6 3.33 1.97 3.08 10.6 0.6 3.28 15.17 12.23
0.8 3.33 1.97 3.30 10.6 0.6 3.28 25.03 14.13
1.0 3.33 1.97 3.32 10.6 0.6 3.28 35.19 15.79
1.2 3.33 1.97 3.32 10.6 0.6 3.28 46.26 17.30
1.4 3.33 1.97 3.32 10.6 0.6 3.28 58.30 18.69
1.6 3.33 1.97 3.32 10.6 0.6 3.28 71.22 19.98
1.8 3.33 1.97 3.32 10.6 0.6 3.28 84.99 21.19
2.0 3.33 1.97 3.32 10.6 0.6 3.28 99.54 22.34
2.2 3.33 1.97 3.32 10.6 0.6 3.28 114.84 23.43
2.4 3.33 1.97 3.32 10.6 0.6 3.28 130.85 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orifice vs Weir.xis
TYPE "G" CATCH BASIN PER SDRSD D-8
LA COSTA RESORT SPA PHASE 3
KNOWN:
Node 8 Design Flow, Q = 5.20 cfs
Per SDRSD D-15, "Drainage Structure Grate", the single grate dimensions are:
Length, L= 3'-4"= 3.33 ft
5, n _ Width, W= 1'-11 Is" 1.97 ft
WEIR EQUATION:
Q = CLH 3/2
where:
ORIFICE EQUATION:
C = Weir Coefficient
= 3.0 when H = 0.5 feet
= 3.3 when H >= 1.0 feet
L = Length of the Weir (feet)
H = Water Height over Weir (feet)
1/2 Q = CA(2gH)
where: C = Orifice Coefficient
= 0.60
A = Cross Sectional Area of Orifice (ft^)
g = Gravitational Constant (32.2 ft/s^)
H = Water Height over Centroid of Orifice (ft)
Caiculations for Catch Basin Type "G" - Single "G-1" per SDRSD D-8:
Water Riser Riser Weir Weir Orifice Orifice Weir Orifice
Height Box Box Coeff. Length Coeff. Area* Flow Flow
Length Width
(ft') (feet) (feet) (feet) (feet) (ft') (cfs) (cfs)
0.2 3.33 1.97 2.80 10.6 0.6 6.56 2.65 14.13
0.4 3.33 1.97 2.92 10.6 0.6 3.28 7.83 9.99
0.6 3.33 1.97 3.08 10.6 0.6 3.28 15.17 12.23
0.8 3.33 1.97 3.30 10.6 0.6 3.28 25.03 14.13
1.0 3.33 1.97 3.32 10.6 0.6 3.28 35.19 15.79
1.2 3.33 1.97 3.32 10.6 0.6 3.28 46.26 17.30
1.4 3.33 1.97 3.32 10.6 0.6 3.28 58.30 18.69
1.6 3.33 1.97 3.32 10.6 0.6 3.28 71.22 19.98
1.8 3.33 1.97 3.32 10.6 0.6 3.28 84.99 21.19
2.0 3.33 1.97 3.32 10.6 0.6 3.28 99.54 22.34
2.2 3.33 1.97 3.32 10.6 0.6 3.28 114.84 23.43
2.4 3.33 1.97 3.32 10.6 0.6 3.28 130.85 24.47
*NOTE: Assumes 50% clogging.
4/25/2007 3:22 PM 2 of 2 H:\EXCEL\2534\03\TYPE G CB-Orifice vs Weir.xis
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 5
HYDRAULIC ANALYSIS
5.1 - STORM LEGEND
DG:mj h:\report5\2S34\03\a03.doc
w.o. 2534-3 5/1/2007 1:55 PM
LEGEND
NODES
CATCH BASIN NODES
PROPOSED STORM DRAIN
CD
PREPARED FOR: STORM LEGEND MAP FOR SHEET
HUNSAKER
& ASSOCIATES
SAN DIECO, INC LA COSTA RESORT & SPA 1
OF
1
PIANNINC
ENQNEERINC
SURVEYINC
10179 Huonekais Street
San Diego^ Ca 92121
PH(B5«)5584500- FX(858)558-1414 CARLSBAD, CALIFORNIA
1
OF
1
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 5
HYDRAULIC ANALYSIS
5.2 - STORM MODEL OUTPUT
DG:mj h:\reports\2534\03\a03.doc
w.o. 2534-3 5/1/2007 1:55 PM
LA COUNTY PUBLIC WOa.KS
PROJECT: LA COSTA RSSORT U SPA PHASE 3
DESIGNSS: MJ
STOSM DRAIN .WALi'SIS
ilNPLT)
CD L2 MA.X Q ADJ Q LENGTH ?L 1 ?L 2 CTL/TM D W S KJ
2 9 0.4 0.4 72.52 63.80 64.80 0.00
R3PT: PC/RD4412.1
DATS: 01/23/07
PAGE 1
Ki-I LC Li
B 1 43.91
2 4 S.2 3.2 5.18 47.91 48.00 0.00 12. 0. 3 0.15 0.20 0.05
2 5 3.1 3.1 158.84 48.33 50-00 0.00 3. 0. 3 0.15 0.20 0.18
2 6 2.4 2.4 35.57 60.33 51.50 0.00 S. 0. 3 0.30 0.20 0.03
2 ^ 1.3 1.3 29.32 61.83 62.50 0.00 8. 0. 3 0.15 0.20 0.05
2 a 0.9 0.9 58.21 52.83 53.50 0.00 5. 0. 3 0.15 0.20 0.05
0. 1 0.00 0.20 0.05
A3 A4
5 0 0 72. 0. 0. 4.00 O.OlO
0 35. 0. 0. 4.00 0.01'D
7 15 0 77. 38. 0. 4.00 0.010
0 39. 0. 0. 4.00 0.010
2 15 0.5 0.5 48.42 51.33 54.30 0.00 5. 0. 1 0.00 0.20 0.03
9 0 0 15.
0 0 0 0. 0.
OOOO.
0. 4.00 0.010
0. 4.00 0.010
0. 4.00 0.010
LA COUNTY PUBLIC WORKS
PROJECT: LA COSTA RESORT i SPA ?:-iASS 3
•SSIGNSH: MJ
STORM DRAIN ANALYSIS REPT: PC/RD4412.2
D.ATE: 01/23/07
P.i^GS 1
LINE Q D W DN
NO ;c?3; (IK) (IN) (FT)
DC FLOW SF-FULL VI V 2 FL 1 HG 1
CALC
HG 2
CALC
D 1
;?T)
D 2 Tl'I
(FT) C21LC
TW
CK RSr'ARKS
I-iYDHA-JLIC QR.^S LINS CO.VT.ROL = 4 8.91
8.2 12 0 1.00 0.99 FULL 0.03134 10.4 10.4 47.91 48.00 43.91 49.07 1.00 1.07 0.00 0.00
3-1 3 0 0.42 0.65 SEAL 0.03894 3.9 8.9 43.33 60.00 53.30 60.55 4.97 0.55 0.00 0.00 HYD JUM?
X - 93.S8 X(Nj - 0.00 X(J) - 98.98 F(J) - 1.28 D(3J) = 0.44 D (AJ)
2-4 8 0 0.S7 0.65 FULL 0.02334 6.9 6.9 60.33 61.50 51.93 53.23 1.60 1.73 0.00 0.00
1-3 3 0 0.35 0.54 FULL 0.00685 3.7 3.7 61.83 52.50 64.51 54.71 2.SB 2.21 0.00 0.00
0.9 5 0 0.50 0.45 FULL 0.01522 4.5 4.6 62.83 53.50 64.90 65.78 2.07 2.28 0.00 0.00
0.4 5 0 0.24 0.32 ?U-LL 0.00301 2.0 2.0 53.80 54.80 SS.31 65.53 2.51 1.73 55.51 0.00
1.54
HYDRAULIC QR.ADE LINS CONTROL - 63.87
O.S 5 0 0.19 0.36 SEAL 0.00470 2.5 3.3
X - 30.12 X(N) = 0.00 X(J) - 30.12 F(J)
51.83 64.30 53.87 64.55
0.12 DOJ) = 0.20 D!AJ)
2.04 0.36 54.85
0.53
0. 00 HYD JUMP
VI, FL 1, D 1 AND KG 1 .REFER TO DOWNSTREAM END
V 2, ?L 2, D 2 .AND HG 2 REFER TO UPSTREAM END
X - DISTANCE IN FEET FROM DOWNSTRS.AM END TO POINT WHERE KQ INTERSECTS SOFFIT IN SEAL CONDITION
X(N) - DISTANCE IN FEET FROM DOKNSTRE.AM END TO POINT WHERE WATER SiJRFACE REACHES NOR-^UU. DEPTH 3Y EITHER DRAWDOWN OR 3.ACKV;ATER
X(J) - DISTANCE IN FEET FROM DOWKSTRE-AM END TO POINT WHERE HyDR.AULlC JU!-!? OCCURS IN LINS
F!J) - THE COMPUTED FORCE AT THE .HYDRAULIC JUM?
D(3j; - DEPTK Or W.ATSR 3HF0RE THS HYD.RAULIC JUMP (UPSTREAM SIDE)
D(AJ) - DEPTH OF W.ATSR .AFTER T.HE KYDPJVULIC JUMP (DOWNSTREAM SIDE)
SEAL INDICATES FLOW GJA-NGES FROM P.ART TO FULL OR FROM FULL TO PART
HYD JUMP INDICATES TI-IAT FLOW CH.ANGS3 FROM SUPERCRITICAL TO SU3CRITICAL T-HROUGH .A HYD.RAULIC JuM?
HJ S UJT INDICATES T:-LAT KVDa.AULIC Jui'i? OCCURS .AT THS JUIJCTIOi.' .AT TKS UPSTRSA-M SND Or Tl-iS LINS
HJ S DJT INDICATES T:--AT HYDRAULIC JUI-l? OCCURS AT THS JUNCTION AT THS DOSi.'NSTRSAl-i END OF THE LINE
1/23/2007 13; 1
La Costa Resort & Spa Phase 3
Drainage Study
CHAPTER 6
HYDROLOGY EXHIBITS
6.2 - MASTER HYDROLOGY STUDY DATA
DGimj h:\reports\2534\03\a03.doc
w.o. 2534-3 5/1/2007 2:24 PM
®0_-50,a,
LEGEND
WATERSHED BOUNDARY —
WATERSHED NODES
SUBAREA ACREAGE ( l-ZAC)
crrv OF CARLSBAD. CAUFORNIA
»\0«SVLHrri\6l9(H0>-Rir-DE:v«.el eSBfiMpr-EM-EDHiEOiSZ
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FIiOW<<<<<
100 YEAR R-AINFALL INTENSITY (INCH/HOtJR) = 4.001
*USER SPECIFIED(SUBAREA):
GENERAL COMMERCIAL RUNOFF COEFFICIENT = .8200
S.C.S. CURVE NUMBER (AMC II) = 0
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6996
SUBAREA AREA (ACRES) = 0.88 SUBARE.A RtJNOFF (CFS) = 2.89
TOTAL AREA(ACRES) = 10.99 TOTAL RUNOFF(CFS) = 30.76
TC(MIN.) = 12.56
****************************************************************************
FLOW PROCESS FROM NODE 520.00 TO NODE 521.00 IS CODE = 41
>>»>COMPUTE PIPE-FLOW TRAVEL TIME THRU SIIB.AREA<««
>>»>USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <<<«
ELEVATION DATA: UPSTREAM(FEET) = 48.41 DOWNSTREAM(FEET) = 46.93
FLOW LENGTH (FEET) = 122.00 M.ANNING'S N = 0.013
ASStME FULL-FLOWING PIPELINE
PIPE-FLOW VELOCITY(FEET/SEC.) = 9.79
PIPE FLOW VELOCITY = (TOTAL FLOW)/(PIPE CROSS SECTION AREA)
GI-VEN PIPE DIAMETER (INCH) = 24.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3 0.76
PIPE TRAVEL TIME(MIN.) = 0.21 Tc(MIN.) = 12.77
LONGEST FLOWPATH FROM NODE 0.0 0 TO NODE 521.00 = 671.90 FEET.
*************************** I I n < I » I ll ^ ^ » n ll ll I » » HI I t I I ll II II II I II I > * * *i i> •• J. * * t ilr •* * *
FLOW PROCESS FROM NODE 521.00 TO NODE 521.00 IS CODE = 81
>>»>ADDITION OF SUBAJIEA TO MAINLINE PEAK FLOW<<<«
100 YEAJl RAINFALL INTENSITY(INCH/HOUR) = 3.958
*USER SPECIFIED(SUBAREA):
GENEPJiL COMMERCIAL RUNOFF COEFFICIENT = .8200
S.C.S. CURVE NUMBER (AMC II) = 0
AREA-A-VERAGE RUNOFF COEFFICIENT = 0.7219
SUBAREA AREA(ACRES) = | 2.50'\ SUBAREA RUNOFF (CFS) = [8.11 7
TOTAi AREA (ACRES) = 13 .45 TOTAL RTINOFF(CFS) = 3 8/55
TC(MIN.) = 12.77
***************************************************************************
FLOW PROCESS FROM NODE 521.00 TO NODE 522.00 IS CODE = 41
>>>>>COMPin'E PIPE-FLOW TRA-VEL TIME THRU SUBAREA<<<<<
>>»>USING USER-SPECIFIED PIPESIZE (EXISTING ELEMENT) <<<<<
ELEVATION DATA: UPSTREAM(FEET) = 46.27 DOWNSTREAM(FEET) = 43.42
FLOW LENGTH(FEBT) = 136.00 M-ANNING'S N = 0.013
ASSUME FULL-FLOWING PIPELINE
PIPE-FLOW VELOCITY(FEET/SEC.) = 12.27
PIPE FLOW VELOCITY = (TOTAi FLOW)/ (PIPE CROSS SECTION AREA)
GIVEN PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3 8.55
PIPE TRAVEL TIME(MIN.) = 0.18 Tc(MIN.) = 12.95
LONGEST FLOWPATH FROM NODE 0.00 TO NODE 522.00 = 807.90 FEET.