HomeMy WebLinkAboutCT 08-06; HIGHLAND JAMES; HYDROLOGIC/HYDRAULIC DRAINAGE REPORT; 2016-10-26HYDROLOGIC/HYDRAULIC DRAINAGE REPORT
100-year Peak Flow in Pre & Post-Development Conditions for:
Highland James Subdivision
Project ID (CT 08-06) COP 15-47, 15-48 & 15-49
Carlsbad, CA, 92008
APN: 207-130-75 to 207-130-78-00
DWG 483-6B & DWG483-6C
Prepared by:
Terramar Engineering
2888 Loker Avenue East, Suite 303
Carlsbad, CA, 92010
760-603-1900
760-603-1909 (fax) LL\N
Phillip James Patague, PE, 84169 Date
Report Prepared:
October 26, 2016
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TABLE OF CONTENTS
Introduction...................................................................................................................................1
ProjectDescription ........................................................................................................................ 1
Location..................................................................................................................................................... 1
Description................................................................................................................................................1
LandUse and Zoning ................................................................................................................................ .1
FEMAConsiderations ...............................................................................................................................2
DrainageAspects ................................................................................................................. ......... 2
ExistingCondition .....................................................................................................................................2
DevelopedCondition.................................................................................................................................3
Hydrology........................................................................................................................ .............. 4
Timeof Concentration ............................................................................................................................... 4
Rational Method (per Section 3.1 of the SDCHM) 5
Modified Rational Method (per Section 3.4 of the SDCHM) ............................
Hydraulics.....................................................................................................................................6
CatchBasin (Weir) .................................................................................................................................... .......6
Graded Trapezoidal Weir .............................................................................. 7
Pipes.........................................................................................................................................................7
Conclusions.....................................................................................................................................9
APPENDIX A: Maps
APPENDIX B: Calculations
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4
HYDROLOGIC/HYDRAULIC DRAINAGE REPORT
100-year Peak Flow in Pre & Post-Development Conditions for
Highland James Subdivision, Carlsbad, CA
INTRODUCTION
This document summarizes the approach used to analyze and compare the hydrologic and
hydraulic volumetric flows of the existing and proposed conditions of a project site in the City of
Carlsbad. In accordance with the Carlsbad BMP Design Manual (2016) and the San Diego
County Hydrology Manual, this report will show that the proposed condition will mitigate
flooding.
In addition to flood control, the proposed drainage of the project site must comply with Pollutant
Control and Hydromodification Management requirements as mandated by the Carlsbad BMP
Design Manual. According to the Carlsbad Watershed Management Area Analysis (WMAA)
prepared by Geosyntec & Rick Engineering (Oct 2014), the project site exists within the
Hydromodification Exempt area and thus does not require a Hydromodification analysis. Please
refer to the "Storm Water Quality Management Plan" (SWQMP)" prepared by Terramar
Engineering for further discussion of Pollutant Control requirements.
PROJECT DESCRIPTION
Location
Street Address: 3980 Highland Drive
City/County/State/Zip: Carlsbad, County of San Diego, California, 92003
Latitude, Longitude: 33'09'13" N, 117 19'44" W
Description
This project consists of a lot subdivision and residential development of 3980 Highland Drive,
Carlsbad, CA (See Location Map in Appendix A). The site area is 49,653 sf. The proposed
residential development will result in the existing lot subdivided into five (5) smaller lots which
will be the location of 5 residences. The total impervious area in the existing and proposed
conditions is 4,340 sf and 22,282 sf, respectively.
Land Use and Zoning
The subject property is the current location of an existing residence and appurtenances
(hardscape and landscape).
In the proposed condition, all 5 lots will be future locations for residences. Access to lots 4 & 5
are afforded by Highland Avenue to the southwest. Access to lots 1, 2 and 3 are afforded by
James Drive to the northeast. Each lot will consist of a residential building, connected garage,
driveway, sidewalk, and landscaping.
Zoning: R-1 (Single-family Residential)
APN: 207-130-75 to 207-130-78-00
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FEMA Considerations
Before proceeding with the calculations, the property was investigated from the Federal
Emergency Management Agency (FEMA) point of view, to determine if the property is located
totally or partially outside of a flood zone.
Community Number: 06073C0764G
Effective Date: 5/16/12
Zone: X (unshaded)
ZONE X (unshaded) is defined as The areas of minimal flood hazard which are the areas
outside the Special Flood Hazard Area (SFHA) and higher than the elevation of the 0.2-percent-
annual-chance flood
DRAINAGE ASPECTS
The project site is the future location of five (5) residences on five (5) individual lots. The
cumulative area of the project site is 1.14 acres The project site generally drains southwest to
northeast (Highland Dr to downstream James Dr) A City storm drain curb inlet along James Dr,
located near the eastern corner of the project site is considered the point of
comparison/compliance (POC)
Existing Condition
The subject site is a residential parcel located on the easterly side of Highland Drive. The
property is located at the top of a rise with the east side of the site fronting James Drive
approximately 15 to 20 feet lower than the west side A 10-foot approximately 2:1 cut slope
extends midway through the site from the south to north A 2-to-3 feet fill slope is located at the
top of the cut on the north end. The property is presently occupied by a one-story single-family
residence with a detached garage and driveway. There is a four-foot retaining wall behind the
garage and a 3-foot rock retaining wall behind the house
There is a 12-inch public storm drain that conveys stormwater runoff from Highland Drive
eastward through the site along its northern perimeter down to James Drive; however the
property does not contain any storm drain infrastructure for stormwater generated onsite.
Existing topography dictates that stormwater runoff sheet flows along the ground surface of the
property from west to east and discharge offsite and onto James Drive at the sites eastern
edge. In pre-development conditions the entire site may be considered as a single drainage
management area with one point of discharge (at its eastern perimeter)
Once the runoff discharges onto James Drive it is collected by a curb inlet on James Drive
which is part of the municipal separate storm sewer system (MS4) owned and operated by the
City of Carlsbad. The City MS4 conveys the runoff further downstream to the Agua Hedionda
Lagoon with ultimate discharge into the Pacific Ocean along Carlsbad State Beach (at
Tamarack jetties and at the discharge for the Encina Power Station).
2
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Developed Condition
In the proposed condition, the natural drainage pattern of the site is roughly maintained. Ridges
and swales divide the site into twelve (12) Drainage Management Areas (DMA). The DMAs are
designated Nia, Nib, Nic, N2a, N2b, N2c, N3, N4, N5, N6, N7 and N8. All DMAs discharge
into a private storm drain system via catch basins and the private storm drain system terminates
at an existing public curb inlet (City MS4). N1a+N1b and N2a+N2b each discharge into a
Bioretention Best Management Practice (BMP) for water quality purposes. Higher flows from the
BMPs enter a concrete swale which terminates at catch basins and enters the private storm
drain system. N3 through N8 flow to catch basins without entering structural BMPs and are
treated by Site Design BMPs. See the Water Quality Management Plan prepared by Terramar
Engineering for a detail explanation of the methodologies used to design BMPs for Water
Quality requirements. The DMAs are described below.
DMA Nia is 0.038-acres (22% impervious) and an area within the public right-of-way
(ROW) that flows onto Nib. Nia consists of landscaping and the driveway for Lot 4 that
ties into Highland Avenue.
DMA Nib is 0.274-acres (41% impervious) and contains proposed Lot 4. Nib accepts
run-on from Nia. Runoff discharges into a Bioretention BMP for pollutant control. Flows
leaving the BMP are managed by infiltration and an overflow weir. The overflow weir
conveys flows to Nic.
DMA Nic is 0.014-acres (0% impervious). This DMA conveys the flow from the
upstream BMP to the private storm drain system. Runoff flows to a riprap drainage swale
which terminates at a catch basin.
DMA N2a is 0.038-acres (22% impervious) and an area within the public right-of-way
(ROW) that flows onto N2b. N2a consists of landscaping and the driveway for Lot 5 that
ties into Highland Avenue.
DMA N2b is 0.274-acres (38% impervious) and contains proposed Lot 5. N2b accepts
run-on from N2a. Runoff discharges into a Bioretention BMP for pollutant control. Flows
leaving the BMP are managed by infiltration and an overflow weir. The overflow weir
conveys flows DMA N2c.
DMA N2c is 0.011-acres (0% impervious). This DMA conveys the overflow from the
upstream BMP to the private storm drain system. Runoff flows to a riprap drainage swale
which terminates at a catch basin.
DMA N3 is 0.082-acres (62% impervious) and contains the southern half of Lot 3. Runoff
from N3 enters the private storm drain system via a catch basin near the northeastern
corner of the DMA
DMA N4 is 0.082-acres (50% impervious) and contains the northern half of Lot 3. Runoff
from N4 enters the private storm drain system via a catch basin near the northern edge
of the DMA.
DMA N5 is 0.082-acres (65% impervious) and contains the southern half of Lot 2. Runoff
from N5 enters the private storm drain system via a catch basin near the northern edge
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of the DMA.
DMA N6 is 0.082-acres (50% impervious) and contains the northern half of Lot 2. Runoff
from N6 enters the private storm drain system via a catch basin near the northern edge
of the DMA.
DMA N7 is 0.082-acres (65% impervious) and contains the southern half of Lot 1. Runoff
from N4 enters the private storm drain system via a catch basin near the northern edge
of the DMA
DMA N8 is 0.082-acres (49% impervious) and contains the northern half of Lot 1 Runoff
from N4 enters the private storm drain system via a catch basin near the northern edge
of the DMA N8 also contains a 12-inch public storm drain with a 5-ft easement along its
northern perimeter that conveys flows from Highland through the site and into storm
drain under James Drive (the project does not contribute runoff to this pipeline)
Nia Nib and Nic will be evaluated as one collective DMA since these DMAs all drain to one
point. N2a, N2b, and N2c will also be evaluated as one collective DMA since these DMAs all
drain to one point.
See Appendix A to see the existing and proposed site layout.
HYDROLOGY
The methodology for this drainage report follows analyses found within Section 3.1 of the San
Diego County Hydrology Manual (hereafter referred to as the "Hydrology Manual').
See Appendix B for the detailed calculations described in the section.
Time of Concentration
The time of concentration (ta) is used to determine the peak flow during a storm event The
value represents the time it takes for the entire area to contribute to runoff and is a function of
flow path length, slope, and surface roughness. An iterative process was used to determine t.
First, the initial time of concentration for the initial 100 feet of flow path distance was determined
using the following equation.
t = 1.8 * (1.1 - C) * -- Equation 1
Where: tci = initial time of concentration in minutes
C = unitless runoff coefficient of the initial area = 0.9*ai + Cp*(1 a1)
C = unitless runoff coefficient of the natural soil (Soil Type B for this site) = 0.25
ai = unitless impervious fraction = impervious area I total area
L = initial flow path length in feet (maximum 100 ft)
S = initial slope of the longest flow path as a percent (%)
With the initial tci evaluated, the subsequent flow velocity of the concentrated flow will be
determined. A final velocity of the channel flow will be estimated and used to estimate the travel
time (ti), which represents the time it takes for the concentrated flow to channelize. Summing t 1
and tt yields the total time of concentration (ta). With t, the outlet volumetric flow Q and flow
4
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velocity v can be determined. The equations for Q are described in sections 'Rational Method"
and "Hydraulics" (Manning's Equation). The estimated final velocity is then iterated until the
value converges on the calculated final velocity. The iteration process will yield the true travel
time between the initial area evaluation point (i.e. 100-ft along the longest flowpath) and the
DMA outlet. Subsequently, the process with yield the correct tc and Q. Table I in the next
section outlines the times of concentration for each DMA (existing and proposed).
Rational Method (per Section 3.1 of the SDCHM)
To determine the 100-yr runoff for each drainage area, the following equation was used.
Q = CIA
Where: Q = runoff in cubic feet per second (cfs)
C = unitless runoff coefficient of the initial area
I = rainfall intensity in in/hr (see below for equation)
A = contributing area in acres
Equation 2
We evaluated the rainfall intensity for each DMA using the following equation (from Figure 3-1 in
the Hydrology Manual).
I = 7.44P6D 0645 Equation 3
Where: 1= rainfall intensity in in/hr
P6 = cumulative precipitation during the most intense 6 hours of the design storm
D duration in minutes
To determine the 100-yr runoff (Q100) of each DMA, we used P6 for the 100-yr event and the
times of concentration for the 100-yr event (analyzed in the previous section) for the duration to
determine the 100-yr peak rainfall intensity. The following table outlines the results from the
Rational Method analysis.
Table 1. 100-yr Hydrology
DMA Tc 1 0
rnin cfs
El 7.1 1.92
N1a+N1b+N1c 5.0 1.09
N2a+N2b+N2c 5.0 1.05
N3 6.5 0.31
N4 9.7 0.21
N5 6.6 0.32
N6 101 0.21
N7 8.3 0.26
N8 8.9 0.22
5
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Modified Rational Method (per Section 3.4 of the SDCHM)
The runoff values in the previous section represent the flows leaving each DMA Each flow will
enter the private storm drain system via a catch basin and confluence before leaving the site
and entering the City MS4. To quantify the confluence flow, we used the process outlined in
Section 3.4 of the Hydrology Manual. At each confluence point, the times of concentration and
runoff values were used in combination with the following set of equations to determine the
resulting flow.
Junction Equation: T1 <T2 <T3
QT1 = Q1+ T1 —Q2 + T1 —Q3
T2 T3
QT2 =
QT3 = Q3 + 13 —Q1+ 13 —Q2
j1 '2
The greatest value of QT1 QT2 and QT3 will be accepted as the resulting flow with the
corresponding time of concentration (e.g. if QT2 was greatest T = T2) This is a conservative
approach, because friction losses were not considered in the confluence. Friction losses would
reduce flow velocity, thus reducing volumetric flow.
HYDRAULICS
See Appendix B for the detailed calculations described in the section
Catch Basin (Weir)
Runoff from each DMA will enter the private storm drain system through a catch basin. Each
catch basin will have a grate of dimension I 'xl', thus providing a weir length of 4'. The available
head for the catch basins is either a maximum 3". To determine the flow capacity of the curb
inlet, the following equation was used.
Qw = CLH15 Equation 4
Where: Qw = volumetric flow of weir in cfs
Cw = unitless discharge coefficient of weir = 3.1 (typical)
L = length of weir = 4 ft
H = available weir head = 3"
The flow capacity for the weir was determined to be 1.55 cfs. The maximum 100-yr runoff
flowing to a catch basin is 1.09 cfs. Therefore, the weirs are sufficiently sized to convey the 100-
yr runoff flows for their respective DMAs.
See Appendix B for the detailed analysis.
101
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Graded Trapezoidal Weir
DMAs Ni and N2's runoff collect in Bioretention BMPs. Lower flows will infiltrate into the soil,
while larger flows will overflow into a concrete channel via a trapezoidal weir graded into the
sloped sides of the Bioretention basin. The concrete channel will convey flow to a catch basin;
the analysis for determining the flow capacity of the catch basin was described in the previous
section.
To determine the flow capacity of the weir, the weir equation from the previous section
(Equation 4) was used. The graded weir was designed as a Cipoletti weir (i.e. 4:1 side slopes),
with available head of 3", and bottom (crest) width of 3 (used as weir length) The discharge
coefficient C will be 3.367 as per Equation 7-7 of the USBR Water Measurement Manual (1997).
With this information and equation 4, the flow capacity of the graded trapezoidal weir was
determined to be 1.26 cfs, which is greater than both Ni and N2's 100-yr runoff flow of 1.09 and
1.05 cfs, respectively. Therefore, the graded weirs are sufficiently sized.
Pipes
The flows within pipes must be evaluated for both the private and public storm drain systems to
ensure that the system is sufficiently sized for the 100-yr storm event To determine the flow
capacities of the storm drain pipes Manning 's Equation (shown below) was used
Q
1.486 A'§ Equation 5
Where QP = volumetric flow in the pipe in cfs
n = unitless Manning 's roughness coefficient = 0.013 (typical for public pipes)
A = cross-section area of flow in ft2
P = wetted perimeter of flow in ft
S = slope of pipe in ft/ft
For the private storm drain system, the flows per pipe were first determined using the Modified
Rational Method described in a previous section. Once the flows for each section of pipe were
determined, Manning's Equation was used to check that the pipes would flow as open channels
(no pressure head) during the 100-yr storm event. See Appendix A for the layout of the private
storm drain pipes The following table summarizes the flow depth in each conduit
Table 2: Pnvate Storm Drain Pipe Hydraulics
Pipe L
ft
S
V0
ci
in
h
ft
A
ft2
P
ft
n
cfs cfs
P1 116.5 2.30% 6 0.41 0.17 1.14 0.011 1.09 1.01
P2 45.6 1.80% 4 0.21 0.06 0.61 0.011 0.22 0.30
P3 16.8 1.96% 8 0.40 0.22 1.19 0.011 1.36 2.00
P4 41.9 1.58% 8 0.45 0.25 1.30 0.011 1.45 1.80
P5 17.4 1.44% 8 0.54 0.30 1.48 0.011 1.68 1.71
P6 117.0 3.65% 6 0.36 0.15 1.01 0.011 1.09 1.27
P7 38.6 0.40% 10 0.56 0.39 1.61 0.011 1.31 1.64
P8 11.7 1 0.70% 12 0.76 0.64 2.12 0.012 2.99 3.23
7
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For Table 2: L = pipe length
S = pipe slope
Qloo = 100-yr flow going to pipe as determined by the Modified Rational Method
d = pipe diameter
A = cross-sectional area of flow within pipe
P = wetted perimeter of flow within pipe
h = depth of flow within pipe
n = Manning's roughness coefficient = 0.011 for PVC or 0.012 for RCP
QfuI = full conduit flow
The following table outlines the results from the hydraulics analysis for the public pipes (City
MS4).
Table 3 'Cs
d 18 48 in
1.8 12.6 ft2
P 4.7 12.6 ft
0.013 0.013
0.245 0.01 ft/ft
52.0 143.6 cfs
56.2 155.1 cfs
3.4% 1.2%
5.8% 2.1%
2.3% 0.8%
For Table 3: d = pipe diameter in inches
A = full pipe cross-section in ft2 = rrd214
P = full pipe perimeter in ft = nd
= full pipe volumetric flow in cfs
Qm = max pipe volumetric flow in cfs = I .08Qf
Qe = 100-yr runoff for the existing conditions 1.92 cfs
= 100-yr runoff for the proposed condition = 2.99 cfs
= increase in runoff = 1.07 cfs
The slopes and dimensions of the city storm drain pipes are referenced from Project No. 2-13
(Plans & Profiles for the Sewer, Water, & Storm Drain Improvements in Holiday Manor),
Drawing No. 135-5, dated 09/06/1962.
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CONCLUSIONS
This report quantifies a 1.07 cfs increase in peak flow discharge rates associated with the
proposed development of the subject property (pre-development peak flow rate = 1.92 cfs, post-
development peak flow rate = 2.99 cfs). This increase constitutes a 2.3% and 0.8% increase in
the flow in the downstream 18" and 48" diameter storm drain pipes, respectively, which should
not have a significant impact on the City storm drain infrastructure.
"I hereby declare that I am the engineer of work for this project. That I have exercised
responsible charge over the design of the project as defined in section 6703 of Business and
Professions code and that the design is consistent with current standards. I understand that the
check of project drawings and specifications by the City of Carlsbad is confined to a review only
and does not relieve me, as engineer of work, my responsibilities for project design. This
Hydrologic/Hydraulic Drainage Report of the Highland James Subdivision in Carlsbad, CA was
prepared by me (or under my supervision) in accordance with the criteria established by the San
Diego County Hydrology Manual, the Carlsbad BMP Design Manual and in accordance with
standard practices"
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APPENDIX A
Pre-Development Conditions Exhibit (with Location Map)
Post-Development Conditions Exhibit
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A.
/ 3960 HIGHLAND ) DRIVE
PRO
LEGEND VICINITY MAP 0
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SCALE: 140 FEET
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0.014 ac
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N4 \ N5 I ' N6 NJ N7 • I N8 082 ac 0,082 ac 0,082 ac 0.082 ac 0.0
DMA AREA (SF) TYPE/NOTES
Nia 1,635 SF N/A - RUNS ON TO Nib (WITHIN PUBLIC ROW)
Nib 11,917 SF FLOWS TO BIORETENTION BMP (INF-2A)
N1c 605 SF N/A - CONVEYS RUN-ON FLOWS TO PRIVATE SD
N2a 1,669 SF N/A - RUNS ON TO N2b (WITHIN PUBLIC ROW)
NI 11,917 SF FLOWS TO BIORETENTION BMP (INF-20)
N2c 484 SF N/A - CONVEYS RUN-ON FLOWS TO PRIVATE SD
N3 3,571 SF SELF-RETAINING AREA (SRA 1)
N4 3,571 SF SELF-RETAINING AREA (SRA 2)
N5 3,571 SF SELF-RETAINING AREA (SRA 3)
3,571 SF SELF-RETAINING AREA (SRA 4) r148
146
147 3,571 SF SELF-RETAINING AREA (SRA 5)
3,571 SF SELF-RETAINING AREA (SRA 6)
IIBIT NOTES:
1. ENTIRE SITE IS UNDERLAIN WITH HYDROLOGIC SOIL GROUP B
// " 2. THE APPROXIMATE DEPTH TO GROUNDWATER IS GREATER THAN 15 FT
/971 JAMES DRIVE/ 3, THE SITE DOES NOT CONTAIN ANY EXISTING NATURAL HYDROLOGIC FEATURES (WATERCOURSES, SEEPS,
SPRINGS, WETLANDS)
4. THE SITE DOES NOT CONTAIN ANY CRITICAL COARSE SEDIMENT YIELD AREAS TO BE PROTECTED
PROPOSED DESIGN FEATURES AND SURFACE TREATMENTS USED TO MINIMIZE IMPERVIOUSNESS INCLUDE TREE
I-/ WFI I S (RMP SD-i) AND IMPERVIOUS AREA DISPERSION (AMP S171,5) SUCH THAT EACH (OF THE DMAs N3 THOI IRGH NH
MAYBE CONSIDERED SELF RETAINING AREAS VIA QUALIFYING SITE DESIGN BMPS
6. STRUCTURAL BMPS WERE INCORPORATED TO MEET WATER QUALITY REQUIREMENTS FOR DMAs Ni & N2.
40 0 20 40 80 160 EX I I
I
I I I I
I SCALE: 1"40 FEET
(T% POST-DEVELOPMENT CONDITION
DRAINAGE AREA MAP
—Q1O0=2.99cis
JAMES DRIVE
41 i:........
APPENDIX B
NRCS Web Soil Survey Hydraulic Soil Group
Hydrology Calculations
Hydraulics Calculations
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it Feet 0 35 70 140 210 "
Map prnjecton \Edb Mertator Corner coordinates: WG584 Edge tes: UrM Zone uN WGS84
USDA Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
4/7/2016
Page 1 of 4
Hydrologic Soil Group—San Diego County Area, California
Hydrologic Soil Group
......
Hydrologic Soil Group— Summary by Map Unit - San Diego County Area, California (CA638)
Map unit symbol Map unit name 7 Rating Acres in AOl Percent of AOl
CbE Carlsbad gravelly loamy B 0.2 21.4%
sand, 15 to 30 percent
slopes
MIC Marina loamy coarse B 0.5 40.7%
sand, 2 to 9 percent
slopes
MIE Marina loamy coarse B 0.4 37.9%
sand, 9 to 30 percent
slopes
Totals for Area of Interest 1.1 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (AID, BID, and CID). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (AID, BID, or CID), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 4/7/2016
Conservation Service National Cooperative Soil Survey Page 3 of 4
Appendix B.2
Speck Carlsbad
100-yr Hydrology Calculations
Site Parameters
C,so110 1 0.25
P6 I 2.60 in
Existing 100-yr Hydrology
DMA A
cf
A
cc
A.rrnp
vi
n,rmp C In S
ft/ft
Li
it
ii Ii
mis LI/hr
Al
cc
ill
cLI
cl Ct
It
Ad
ft
vi
ft/v
L
ft
L?
ft
VI
ft/v
12 Ic
iLIh mCi in/hr
LI Ir2
it
Ad
f .:ftt
v2f
El 1 496531 1.141 43401 0.091 0.311 0.0201 0.111 1001 6.421 5.831 0.171 0.301 501 0.051 0.141 2.21 3441 2441 4.11 0.6517.071 5.481 1.921 251 0.1371 0.47 4.1
Proposed 100-yr Hydrology
L/h/tA tLI riiri /i,iriic C n S
ft It
C
11
Li
It
TI
riirr
Li
Ir hr
Al /1!
cf
ti fri
ft
Ad
ft
vi
It
LI
ft it miii
Cc
mn iii hi
Cr
1
r2 LI
It
.An7 H
ft ft/5
Nla 1635 0.038 352 02
Nlb 11917 0.274 4860 0.4
Nic 605 0.014 0 0.0
N1a + Nlb + Nlc 0.325 5212 0.37 0.491 00141 01351 1951 1001 4.621 6.851 0.1661 0.561 501 0.0561 0,161 3.61 951 8.31 0,131 4.71 6,851 1.091 31 0.2091 0.131 8.3
N2a 1669 0.038 361 0. 22
N2b 11917 0274 4545 0.38
N2c 484 0.0111 0 0.00
N2a + N2b + N2c 0.3231 4906 0.35 0.48 0.014 0.121 194 1001 4.89 6.85 0.323 1,05 501 0.072 0.26 4.01 941 7.9 0.13 5.0 6831 1.051 31 0.210 0.131 7.9
N3 3571 0.082 2202 0.62 0.65 0.013 0.018 97 97 6.55 5.76 0.082 0.31 501 0.063 0.20 1.5
N4 3571 0.082 1782 0.50 0.57 0.013 0.010 143 100 9.46 4.54 0.047 0.12 501 0.050 0.13 1.0 431 1.71 0.271 9.71 4.461 0.211 101 0.112! 0.13j 1.7
NS 3571 0.082 2309 0.65 0.67 0.013 0.014 90 90 6.56 5.75 0.082 0.32 50 0.067 0.22 1.4
N6 3571 0.082 1798 0.50 0.58 0.013 0.008 118 100 9.97 4.39 0.051 0.13 50 0.053 0.14 0.9 18 1.6 0.12 10.1 4.35 0.21 10 0.115 0.13 1.6
N7 3571 0.082 2172 0.61 0.65 0.013 0.010 123 100 8.18 4.99 0.043 0.14 50 0.052 0.14 1.0 23 1.8 0.14 8.3 4.93 0.26 10 0.122 0.15 1.8
N8 3571 0.082 1765 0.49 0.57 0.013 0.013 139 100 8.72 4.79 0.057 0.16 50 0.052 0.14 1.1 39 1 Q1 0.22 8.9 4.71 0.22 10 0.109 0.12 1.9
4 b53I 1.141 1114b1
Page 1 of 1
DMA Tc ft 01n
rain in/hr cfr cfr
011 4.75 6.85 1.36 1.45
N6 10.1 4.35 0.21 1.07
012 1.45 €0
Tc 4.75 mm
DMA Tc I ft ftln
€€ii a in / hr c ft Jr
QT2 4.75 6.85 1.45 1.68
N5 6.56 5.75 0.32 1.54
013 1.68 cfs
Tc 4.75 mm
d 18 48
A 1.8 12.6
P 4.7 12.6
n 0.013 0.013
5 0.245 0.01
Qf 52.0 143.6
ri, 56.2 155.1
e/Qn, 3.4% 1.2%
0/Orn 5.8% 2.1%
,,,Q/Qm 2.3% 1 0.8%
A
in N3 N6 Nb
ft2 On 0.31 0.21 0.22
ft d 6 4 4
A 1 0.2 1 0.1 0.1
ft/ft P 1.6 1.0 1.0
cfs a 0.011 0.011 0.011
cfs 5 0.005 0.058 0.005
Of 0.47 0.54 0.16
Oar 0.51 0.59 0.17
Cm 3.1 3.367
_ 4
H 3
--
Ow 1.55 1.26
Qf1 1.09 1.09
i1..1/Qm1 142% 1 116%
j
ft
in
cfs
cfs
I Appendix 6.3 . Speck Carlsbad
100-yr Hydraulics Calculations
N2a+
N2b Pt
N7 QT1 P3
N8 P2 N6 0T2 P4
NS 0T3 P5
N4 QTS
N1a+N1 - Pb QT4 P1
b+N1c
N3
Pronosed Hydraulics
Pipe irrihunn, L S Tc I ft r d a h Ax P a ft 0011
Are--.,, ft 0 min mn/hr Jr fp: in I deg ft ft2 ft cft cfs
P1 N2a, N2b, N2c 116.5 2.30% 4.75 6.85 1.09 6.3 6 260 0.41 0.17 1.14 0.011 1.09 1.01
P2 NB 45.6 1.80% 8.94 4.71 0.22 3.8 4 211 0.21 0.06 0.61 0.011 0.22 0.30
IN12a, N2b, N2c, 16.8 1.96% 4.75 6.85 1.36 6.2 8 204 0.40 0.22 1.19 0.011 1.36 2.00 N7, N8
N2N2bN2c 41.9 1.58% 4.75 6.85 1.45 5.7 8 223 0.45 0.25 1.30 0.011 1.45 1.80
P5 N2N2bN2C 17.4 1.44% 4.75 6.85 1.68 5.6 8 255 0.54 0.30 1.48 0.011 168 1.71 N5,N6,N7.N8 11
P6 Nia, N1b, Nic 117.0 3.65% 4.75 6.85 1.09 7.3 6 231 0.36 0.15 1.01 0.011 1.09 1.27
Nia, N1b, Nic, 38.6 0.40% 4.75 6.85 1.31 3.3 10 222 0.56 0.39 1.61 0.011 1.31 1.64
16.85 P8 All 11.7 0.70% 4.75 2.99 4.7 12 243 0.76 0.64 2.12 0.012 2.99 3.23
Confluence Analyses
DMA Ic
nun
I
in/hr
ft
cfs
ftln
€0
N2a + N2b 4.75
+_N2c
6.85 1.09 1.36
N7 8.32 4.93 0.26 1.25
NB 8.94 4.71 0.22 1.22
QT1 1.36 €0
1€ 4.75 mm
DMA T
rain
I
in/hr
ft
cfr
ftln
cfr
Nia + Nib 4.75 +_Nic
6.85 1.09 1.31
N3 6.55 5.76 0.31 1.22
0T4 1.31 cfs
Tc 4.75 mm
Weir Hydraulics
DMA T I 0 ftln
aria n/hr €0 €0
QT4 4.75 6.85 1.31 2.99
QT3 4.75 6.85 1.68 2.99
015 2.99 cfs
Tc 4.75 main
Public Pipe Hydraulics Pipe Hydraulics for Minor SD P
Page 1 of 1