HomeMy WebLinkAbout3338; Agua Hedionda & Calavera Creek Dredging; Rancho Carlsbad Mobile Home Park Agua Hedionda; 2005-12-12RANCHO CARLSBAD MOBILE HOME PARK
ALTERNATIVE ANALYSIS FOR
AGUA HEDIONDA CHANNEL MAINTENANCE
Job Number 13182-D
Dennis C. Bowling,
RCE #32838, Exp.
Prepared For:
City of Carlsbad
David Hauser
163 5 Faraday Ave
Carlsbad, CA 92008
Prepared by:
Water Resources Division
Rick Engineering Company
5620 Friars Road,
San Diego, California 92110
(619) 291-0707
www.rickengineering.com
m
December 13,2004
Revised December 12,2005
TABLE OF CONTENTS
*•
m Introduction 1
>"" Exhibit 1. Rancho Carlsbad Mobile Home Park Vicinity Map 4
^^Exhibit 2. Agua Hedionda Basin Flood Control Projects 5
* Exhibit 3. Agua Hedionda Creek and Calavera Creek Watershed Map 6
m Exhibit 4. Flood Insurance Rate Map (FIRM) , 7
"* Hydrologic Analysis 8
H
Table 1: Description of Detention Basins 10
** Table 2: 100-year Discharges in Calavera Creek and Agua Hedionda
• Creek within the Rancho Carlsbad Mobile Home Park 13
m Project Constraints 14
** Hydraulic Analysis 16
m Table 3. Anticipated Detained 100-year WSELs for the Agua Hedionda Creek
w Grading Alternatives and Number of Inundated Lots 21
Exhibit 5. Alternative A Approximate Limits of Grading 22
** Exhibit 6. Alternative B Approximate Limits of Grading 23
Exhibit 7. Alternative C Approximate Limits of Grading 24
ttM
^ Ongoing Maintenance Program 27
mm Conclusion 28
pm Table 4. Matrix Summary of Proposed Agua Hedionda Creek
Maintenance Alternatives 29
*. APPENDICES (on CD)
Appendix A: Referenced Plans
• "Grading Plan Rancho Carlsbad Mobile Home Park," June 27, 1969,
*•• South Bay Engineering
,„ • "Cannon Road Bridge Over Agua Hedionda General Plan," sheet 59 of
131, February 19, 1998, McDaniel Engineering (Drawing No. 333-2G)
*" • "El Camino Real Bridge Widen Over Agua Hedionda Channel General
m Plan," sheet 68 of 131, February 19, 1998, McDaniel Engineering
(Drawing No. 333-2G)
** • "Lake Calavera Remedial Improvements General Site Plan," sheet 6 of 35,
II "Lake Calavera Remedial Improvements Civil Site Plan 1," sheet 7 of 39,
"Lake Calavera Remedial Improvements Concrete Spillway Sections,"
** sheet 10 of 39, "Lake Calavera Remedial Improvements New Outlet Pipe
** Section," sheet 24 of 35, October 2003, CGvL Engineers (Drawing No.
411-6)
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Revised: 12-12-05
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• Grading Plans for Melrose Detention Basin Outlet: "Palomar Forum Melrose Drive"
sheet 11 of 17, June 3,2004, O'Day Consultants (Drawing No. 399-4A)
• Grading Plans for Faraday Detention Basin Outlet: "Carlsbad Oaks North
Faraday Ave," sheet 20 of 37, February 2003, O'Day Consultants
(Drawing No. 415-9C)
• Grading Plans for Detention Basin BJB: "Calavera Hills Phase II," sheet 5
of 80, October 22,2002, O'Day Consultants (Drawing No. 390-9A)
• Grading Plans for Detention Basin BJ: Base Map "City of Carlsbad
Orthophoto Mapping," sheet 55 of 225, Copyright 1991 (Drawing No.
296-5)
Appendix B: Back-up Hydraulic Calculations
• Detention Basin Outlet Structure at Melrose
• Detention Basin Outlet Structure at Faraday
• Detention Basin Outlet Structure at BJB
• Capacity of 8x8 RCB at El Camino Real
Appendix C: Hydrologic Analyses
• 100-Year Ultimate Detained HEC-1 (FN: RC1 OO.HC 1)
• 100-Year Ultimate Undetained HEC-1 (FN: RCUNDET.HC 1)
• 100-Year, 24-Hour Precipitation Map
• HEC-1 Workmap with USGS Topographic Map
Appendix D: HEC-RAS Analysis of No Action Alternative (Executable Files: Project -
RanchoCarlsbadAH.prj; Plan - RanchoCarlsbadAH.pO 1; Geometry -
RanchoCarlsbadAH.gOl; Steady Flow - RanchoCarlsbadAH.f04)
Appendix E:HEC-RAS Analysis of Existing Detained Alternative
(Executable Files: Project - RanchoCarlsbadAH.prj; Plan -
RanchoCarlsbadAH.p07; Geometry - RanchoCarlsbadAH.
RanchoCarlsbadAH.fO 1)
; Steady Flow -
Appendix F:HEC-RAS Analysis of Alternative A
(Executable Files: Project - RanchoCarlsbadAH.prj; Plan -
RanchoCarlsbadAH.p02; Geometry -RanchoCarlsbadAH.g21; Steady Flow-
RanchoCarlsbadAH.fO 1)
Appendix G: HEC-RAS Analysis of Alternative B
(Executable Files: Project-RanchoCarlsbadAH.prj; Plan-
RanchoCarlsbadAH.p24; Geometry-RanchoCarlsbadAH.g23; Steady Flow •
RanchoCarlsbadAH.fOl)
Appendix H: HEC-RAS Analysis of Alternative C
(Executable Files: Project - RanchoCarlsbadAH.prj; Plan -
RanchoCarlsbadAH.p27; Geometry - RanchoCarlsbadAH.g26; Steady Flow •
RanchoCarlsbadAH.fO 1)
Prepared by:
Rick Engineering Company - Water Resources Division
DCB:KH:kw/Report/l 3182-D.002
12-13-04
Revised: 12-12-05
MAP POCKETS
p
W
Map Pocket 1 :
Preliminary Rancho Carlsbad Channel and Basin Project 100- Year Floodplain
Alternatives
Map Pocket 2:
HEC-RAS Workmap (Available on Request)
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Rick Engineering Company - Water Resources Division 12-13-04
Revised: 12-12-05
INTRODUCTION
The purpose of this report is to summarize the design alternatives for Agua Hedionda Creek that
have been prepared by Rick Engineering Company for the City of Carlsbad as part of the Rancho
Carlsbad Channel and Basin Project. The Rancho Carlsbad Mobile Home Park (RCMHP) is an
existing residential area located north-east of El Camino Real, south-east of Cannon Road and
south-west of College Boulevard Reach 'A,' within the City of Carlsbad, California (see Exhibit
1 on page 4).
RCMHP contains portions of both Agua Hedionda and Calavera Creeks. Agua Hedionda Creek
flows westerly through the southern portion of RCMHP. Calavera Creek flows southwesterly
along the northern property boundary. The confluence of Calavera Creek with Agua Hedionda
Creek within the RCMHP is located approximately 300 feet upstream of El Camino Real. The
Agua Hedionda Creek and Calavera Creek watersheds are shown on Exhibit 3 (page 6).
Original Channel Design
The original constructed Agua Hedionda Creek channel was an earthen trapezoidal channel, as
shown on the "Grading Plans for Rancho Carlsbad Mobile Home Park" dated June 27, 1969
prepared by South Bay Engineering (Appendix A). The overall length of the channel was
approximately 1.2 miles and included both Agua Hedionda Creek and Calavera Creek. The side
slopes were 2:1 (horizontal:vertical) and the approximate average bed slopes were 0.15 and 0.30
percent in Agua Hedionda Creek and Calavera Creek, respectively. The bottom width of Agua
Hedionda Creek varied from 58 feet at the El Camino Real Bridge to 44 feet upstream of the
confluence. The approximate channel depth was 11.5 feet. The bottom width and channel depth
of Calavera Creek were 4 feet and 9 feet, respectively.
Sedimentation Pattern within the Channels
Historically, Agua Hedionda Creek has been highly subject to sedimentation within the channel
along areas of the entire creek. Portions of the channel have experienced up to 6 feet or more of
sediment deposition within the Mobile Home Park. This high sediment load may be the result of
large agricultural areas upstream of the RCMHP as well as the effects of an increased peak
discharge within Agua Hedionda Creek due to development within the upstream watershed.
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Revised: 12-12-05
m Because of the increased peak discharge and the accumulation of sediment in the channel over
H time, the capacity of Agua Hedionda Creek to convey storm water through the RCMHP has
„„ diminished, and currently a large number of properties within the Mobile Home Park are subject
m to inundation during a 100-year storm event.
KM
•i Calavera Creek has been subject to erosion within the upstream portion of the channel and
M sedimentation within the downstream portion of the creek near the confluence with Agua
IW Hedionda Creek. As a result of the sedimentation and the encroachment of homeowners into the
m channel, Calavera Creek no longer has capacity for the 100-year storm event.
m
w» Proposed Channel Maintenance
** In an effort to alleviate flooding within the Mobile Home Park, the City of Carlsbad has
w investigated several alternatives to increase the capacity of the creeks and improve flood
^M protection in the area. Rick Engineering Company prepared a study entitled, "Rancho Carlsbad
** Channel and Basin Project," dated June 30, 1998 that provided the preliminary design of four
^_detention basins within the watershed tributary to the RCMHP, determined the maintenance and
p" sediment removal required to return Agua Hedionda and Calavera Creeks to their original design
configurations per the 1969 Grading Plans, and analyzed the effects of the reduced flow and
*"" restored channel capacity on the limits of inundation within the Mobile Home Park.
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*""* Since the 1998 study, further modifications to the proposed maintenance improvements were
M required. These modifications include updates to the hydrologic model, exclusion of Calavera
*"" Creek from maintenance and grading activities, the analysis additional alternatives, as well as
final design plans and calculations of three of the four proposed detention basins. The "Project
Constraints" section of this report addresses in detail the background of the required
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modifications.
The existing Calavera Creek channel configuration results in split flow, with some flow being
Ml conveyed north of the wall along the RCMHP as shown on Exhibit 4, the Flood Insurance Rate
Map (FIRM) panel number 06073C0768 F dated June 19, 1997 (page 7). The original Channel
„ and Basin Project design called for maintenance of Calavera Creek (i.e. widening the creek),
which would force all of the flow into Calavera Creek thereby eliminating the split flow to the
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Rick Engineering Company - Water Resources Division 2 12-13-04
Revised: 12-12-05
north side of the wall. Environmental and biological constraints called into question the
practicality of the previously proposed maintenance and grading within Calavera Creek. Other
constraints include the encroachment of homeowners into Calavera Creek, which introduces
constructability issues of any grading along the channel banks. Preserving the current capacity of
Calavera Creek though maintaining the split flow situation to convey the 100-year storm can
avert maintenance within Calavera Creek. The proposed split flow scenario presented in this
report requires less flow be diverted to the north side of the wall than the existing FEMA-
mapped condition.
The maintenance of Agua Hedionda Creek in conjunction with the construction of the proposed
detention basins will provide hydraulic benefits to Calavera Creek and increase the capacity of
the channel for flood protection. This report presents several alternatives for maintenance of
Agua Hedionda Creek to restore flood protection within the RCMHP. Some alternatives require
grading south of El Camino Real, which was not proposed in the 1998 study. The locations of
the proposed flood control projects discussed in this report are shown on Exhibit 2 on page 5.
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REK ENGINEERING COMPANY
EXHIBIT 2
LAKE CALAVERA
OUTLET IMPROVEMENTS
RANCHO CARLSBAD
MOBILE HOME
PARK
AGUA HEDIONDA
CREEK
DREDGING
FARADAY
BASIN EXHIBIT 3
AGUA HEDIONDA CREEK
AND CALAVERA CREEK
WATERSHED MAP
12-12-05
MELROSE
BASIN
Legend
Major Watersheds
Detention Basins RICK ENGINEERING GOMRW
F
APPROXIMATE SCALF IN FEET
500 _ 0 500
NATIONAL FLOOD INSURANCE PROGRAM
FIRM
FLOOD INSURANCE RATE MAP
SAN DIEGO COUNTY,
CALIFORNIA AND
INCORPORATED AREAS
PANEL 768 OF 2375
(SEE MAP INDEX FOR PANELS NOT PRINTED)
CONTAINS:
COMMUNITY
CARLSBAD. CITY OF
NUMBER PANEL SUFFIX
060285 0768
MAP NUMBER
06073C07B8 F
EFFECTIVE DATE:
JUNE 19,1997
Federal Emergency Management Agency
This Is an official copy of a portion of the above referenced flood map. It
was extracted using F-MIT On-Une. This map does not reflect changes
or amendments which may have been made subsequent to the date on the
title block. For the latest product information about National Rood Insurance
Program <ood maps checK the FEMA Flood Map Store at www.msc.fema.gov
„ HYDROLOGIC ANALYSES
_ The U.S. Army Corps of Engineers Hydrologic Engineering Center HEC-1 computer program
«• was used to prepare hydro logic models of the watersheds tributary to Agua Hedionda Creek and
m Calavera Creek upstream of the Rancho Carlsbad Mobile Home Park. The hydrology was used
*" to determine preliminary detention basin sizes and outlet structures for four proposed detention
H basins upstream of the Rancho Carlsbad Mobile Home Park; two within Agua Hedionda Creek,
*• one at Melrose Drive and one at Faraday; and two within Calavera Creek, Basins BJ and BJB,
*» near the intersection of the Cannon Road and College Boulevard extensions. The hydrology was
IK also used as a source in the HEC-RAS hydraulic analyses.
|^t Since the publication of the 1998 study there have been several modifications to the hydrologic
m analysis of the watershed related to the hydrologic modeling parameters, Calavera Dam, and
final design of three of the proposed detention basins.
HI Hydrologic Modeling Parameters
""" One aspect of the hydrologic modeling parameters that has been modified since the initial study
was the channel Manning's "n" and basin factor values used to calculate the lag time for each
"" watershed. Since the hydrology is based on the ultimate development of the watershed, the
Manning's "n" and basin factor values were originally based on a typical developed condition for
"" the land-use type dominant in each watershed. However, based on current California State
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Water Resources Control Board requirements for new developments, the tendency is less directly
connected impervious surfaces, resulting in a higher Manning's "n" and higher basin factors due
to more natural channels. Therefore, the hydrologic model was updated to reflect this change.
Calavera Dam
The City of Carlsbad has recently initiated a project involving the restoration and reconstruction
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of the outlet structure for Calavera Dam. The modifications include replacing the existing outlet
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tower, which currently does not function, with a new one. The new outlet tower will allow the
lake to be drawn-down in anticipation of large storm events, resulting in a lower peak flow out of
Calavera Lake, which has resulted in a change in the hydrology upstream of detention basin BJB.
The project is currently scheduled to go to bid in the Spring/Summer 2005. The hydrologic
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„ model was updated based on the following assumptions to reflect the impacts of drawdown of
m Calavera Dam on the peak discharge in Calavera Creek.
— • Lake elevation is at 209' (the crest of the outlet tower) when the storm begins
""" • The 3 valves are opened once the storm starts
"* • Valve geometry can be found on sheet 24 on the improvement plans prepared by CGvL
ign
Engineers titled "Lake Calavera Remedial Improvements" (Drawing #: 411-6, dated
* October 2003, Appendix A)
• Spillway elevation is at 214.5' per sheet 6 of the aforementioned plans
m
m These analyses result in a 100-year peak flow into Lake Calavera of 1,831 cubic feet per second
(cfs) and a peak flow out of Calavera Dam of 967 cfs with a maximum ponded water surface
elevation (WSEL) of 219.2'.
Detention Basin Design
The goal of the detention basins proposed by the 1998 study is to detain less than 50 acre-feet of
volume, to avoid being within the jurisdiction of the California Department of Water Resources
Division of Safety of Dams (DSOD). The modifications to the hydrology, as well as the analysis
of the final basin grading, has resulted in some changes to the outlet structure geometries.
Three of the four proposed detention basin outlet structures have been designed. The Melrose
detention basin outlet design prepared by O'Day Consultants (Drawing #: 399-4A, dated June 3,
2004) has been signed and approved by the City of Carlsbad. The Faraday detention basin outlet
design prepared by O'Day Consultants (Drawing #: 415-9C, dated February 2003) has also been
approved. Based on the modifications to the hydrologic modeling parameters and the Calavera
Dam outlet, as well as the final design information provided by the City of Carlsbad for the
Faraday and Melrose basin grading, the detention basin routing has been updated. Copies of the
plans are included in Appendix A for reference and copies of the hydraulic calculations
(prepared by Rick Engineering Company) for the outlet structures are included in Appendix B.
The construction of detention basin BJB was completed with the construction of the College
Boulevard and Cannon Road extensions per the plans prepared by O'Day Consultants dated
October 22, 2002 (Drawing #:390-9A sheet 5 of 80, Appendix A). However, the outlet structure
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9 Revised: 12-12-05
for detention basin BJB will ultimately require modifications to further reduce flows once the
Calavera Dam improvements are constructed to maximize the flood control benefit of Basin
BJB. Copies of the hydraulic calculations (prepared by Rick Engineering Company) for the BJB
outlet structure are included in Appendix B.
Detention basin BJ is still modeled based on the preliminary design outlined in the 1998 report.
The preliminary plans are based on the map titled "City of Carlsbad Orthophoto Mapping" sheet
55 of 225, Copyright 1991 (Appendix A).
Table 1 provides a detailed summary of the detention basins.
Table 1: Description of Detention Basins
Location of
Detention
Basin
Melrose
Faraday
BJB*
BJ++
Q100
(cfs)
In
839
906
1094
629
Out
489
642
901
348
Max.
ponded
WSEL
(feet)
330.5
241.4
75.16
75.9
Max.
Inundation
Area (ac)
6.8
6.8
2.4
8
Max. Storage
Volume
(ac-ft)
44.2
49.8
49.9
48
Outlet Structure Details
Box culvert with a rectangular orifice 5.6'
wide x 4' tall (FL @ 308.0')
Box culvert 4.3' wide x 5.7' tall (FL @
221.8')
72" RCP (FL @ 65.0') and a rectangular
box culvert 1 1' wide x 7' tall with a 10' wide
x 7' tall square-edged entrance (FL @
62.0') *
Rectangular box culvert 6' wide x 3' tall
. (FL@62')++
* The ultimate configuration of detention basin BJB will require construction of a 7.5' x 7' rectangular opening over
the 10' x 7' box and a V-notched opening with a 0.1' bottom width and a 1.4' top width placed over the 72" RCP to
maximize the storage in the basin once the Calavera Lake Dam improvements are constructed.
""" Preliminary design per 1998 Channel and Basin Project report. Subject to revision pending final design
FEMA Drainage Patterns
The current effective Federal Emergency Management Agency (FEMA) study for Calavera
Creek shown on the FIRM Panel number 06073C0768 F, dated June 19,1997 (page 7) shows the
flow splitting to the north and south sides of the existing concrete wall that is located along the
creek. Per the FEMA Flood Insurance Study (FIS), the total flow in Calavera Creek is 1350 cfs.
The FEMA models show approximately 805 cfs conveyed through Calavera Creek on the north
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side of the existing wall, and 545 cfs conveyed on the south side of the wall within the Calavera
Creek Channel in the RCMHP.
Modified Drainage Patterns
The analysis in the 1998 report assumed the entire flow from Calavera Creek would be conveyed
through the RCMHP because the flow would be concentrated from Basin BJB and the channel
would be graded to increase capacity (i.e. flow would not split to the north side of the wall).
However, the project approach to Calavera Creek was modified since the initial study for several
reasons. The majority of property owners adjacent to Calavera Creek have encroached into the
creek with the construction of decks, patios, retaining walls, and landscaping. Any grading
activities within the channel would result in the removal of the structures which will not be
acceptable to many of the RCMHP residents. Also, preliminary biological investigations of
Calavera Creek identified mature oaks and willows established within the channel. The removal
of these mature trees would require extensive mitigation. If the trees were attempted to be
preserved by relocation or structural measures (e.g. retaining walls, etc.), the engineering and
construction costs would be extremely high and the survival rate of the trees is unknown.
Because the Calavera Creek channel does not have capacity for the entire flow in its current
condition, a split flow scenario that more closely mimics the current FEMA model was created
by the construction of a weir near the outlet of detention basin BJB at the entrance to Calavera
Creek. The proposed split flow will result in the conveyance of approximately 500 cfs along the
north side of the wall adjacent to the RCMHP and Calavera Creek. This flow will be conveyed
under Cannon Road through triple 10' wide x 7' tall reinforced concrete boxes (RGB), under El
Camino Real through an existing 8' x 8' RGB, and combine with Agua Hedionda Creek
upstream of the Cannon Road Bridge prior to discharging into Agua Hedionda Lagoon.
The 8' x 8' RGB beneath El Camino Real is a restriction of the amount of flow that can split to
the north side of the wall at the weir. If too much flow splits to the north, flow will overtop El
Camino Real at a low point in the road (elevation = 41.3') just upstream of the 8' x 8' RGB. The
peak discharge to be conveyed north of the wall was determined based on the capacity of the
existing 8' x 8' box assuming 500 cfs is diverted to the north side of the wall. Calculations
included the preparation of a HEC-2 hydraulic model for the north side of the wall extending
from the weir to the downstream face of the 8' x 8' box and a WSPGN hydraulic model of the 8'
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11 Revised: 12-12-05
x 8' box. The following flow rates from the HEC-1 were input into the HEC-2: 500 cfs at the
weir, 522 cfs at the Cannon Road triple RCBs, and 568 cfs at the 8' x 8' RGB. Based on results
from the HEC-2 the WSEL at the location of the low point in El Camino Real was 39.6,' which
results in 1.7' of freeboard. The HEC-2-calculated WSEL at the upstream face of the 8' x 8'
RGB was compared to the WSPGN-calculated WSEL at the same location for verification.
Copies of the WSPGN, HEC-2, and HEC-2 workmap are included in Appendix B.
It should be noted that due to environmental considerations from the resource agencies, frequent
storm flows from detention basin BJB that result in a peak discharge of less than approximately
300 cfs will be conveyed in Calavera Creek without flow splitting to the north side of the wall.
Any modifications to the split flow or the drainage patterns on the north side of the wall should
be designed to maintain this scenario, and not intercept any portion of flows less than
approximately 300 cfs to preserve the downstream habitat.
The drainage basin modeling in the HEC-1 has been modified since the preparation of the 1998
study to reflect the split flow scenario. Refer to Appendix C for HEC-1 hydrologic calculations.
Table 2 shows a comparison of the 1998 study hydrologic results to those of the current 2004
study.
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Table 2:100-year Discharges in
Calavera Creek and Agua Hedionda Creek within the
Rancho Carlsbad Mobile Home Park
Location
Calavera Creek
upstream of the
Mobile Home Park
Calavera Creek north
of the wall (within
Robertson Ranch)
Calavera Creek
upstream of the
confluence with Agua
Hedionda Creek
Agua Hedionda Creek
upstream of the
confluence with
Calavera Creek
Agua Hedionda Creek
downstream of the
confluence with
Calavera Creek
Existing
Condition
(FEMA)
1350
805
545
7810
8080
1998 Hydrology*
City of Carlsbad
Ultimate Developed
Condition
(Existing Hydrology)
1910
N/A
8050
9950
Preliminary Ultimate
Developed Detained
Condition (Proposed
Hydrology)
1550
N/A
7600
8970
2004 Updated Hydrology
Undetained
Hydrology
1419
1410
7795
9195
Detained
Hydrology
749
500
756
7338
8092
PI
m
p
H
* Source: "Rancho Carlsbad Channel & Basin Project" dated June 30, 1998 (Rick Engineering Company)
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PROJECT CONSTRAINTS
Additional factors affecting the limits of grading of this project have impacted the proposed
Agua Hedionda channel grading. These factors include, but are not limited to: the proximity of
the project to the Coastal Zone, the presence of native and non-native trees along the channel
banks, environmental processing requirements, and channel vegetation.
Coastal Zone
The limits of the Coastal Zone are located along El Camino Real in the vicinity of this project.
Any maintenance alternative proposing to grade between El Camino Real arid Cannon Road
would require additional permits and coordination with the Coastal Commission. This area is
within the Local Coastal Zone administered by the City Council. The Coastal Commission could
appeal any decision to allow grading or maintenance within the proposed channel downstream of
El Camino Real.
Native and Non Native Trees within the Channel
The RCMHP Homeowners Association and the Environmental Resource Agencies have voiced
concerns regarding the removal of mature trees and native trees along the Agua Hedionda Creek
bank. In order to preserve as many existing mature trees as possible within Agua Hedionda
Creek, a site visit was conducted with representatives from Rick Engineering Company,
RECON, RCMHP, and the City of Carlsbad in the spring of 2002 to identify the native and
exotic trees along the channel to determine what trees located on the channel banks could be
preserved during the proposed maintenance. Survey data was also collected to assist in
determining the maximum limits of grading along Agua Hedionda Creek. Due to the location of
these trees along the channel side-slopes, the original channel bottom widths as shown on the
"Grading Plans for Rancho Carlsbad Mobile Home Park" dated June 27, 1969 prepared by South
Bay Engineering can not be completely restored.
Environmental Processing
The Agua Hedionda Creek maintenance project involves activities within a jurisdictional water.
Therefore, this project would require processing through the California State Water Resources
Control Board, the U.S. Army Corps of Engineers, as well as the California Department of Fish
and Game. The detention basins proposed at Melrose, Faraday, BJB, and BJ are subject to
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m separate processing through the resource agencies as part of their associated development
ii projects since their construction is linked to the construction of adjacent developments, not to the
mm maintenance of AguaHedionda Creek channel.
*n
MM Channel Vegetation
•" The existing condition hydraulic analyses of Agua Hedionda Creek that are discussed later in this
m report show high velocities throughout the creek especially at bridge crossings during largell
storm events. The high velocities as well as ongoing maintenance by the residents of the
* RCMHP have prevented significant establishment of mature vegetation within the main channellli - •
bed of Agua Hedionda Creek upstream of El Camino Real. The side slopes of the channel have
** become vegetated with mostly ornamental and exotic species presumably planted by thefg
residents of the Mobile Home Park. Therefore, maintenance of the Agua Hedionda Channel
** within RCMHP is expected to have little impact to environmentally sensitive habitat. The
ti hydraulic analysis of Agua Hedionda Creek assumes that the channel will continue to be
*"* maintained regularly and the establishment of mature vegetation within the channel will be
prevented.
Due to the above-mentioned factors, the original design configuration of Agua Hedionda Creek
cannot be completely restored. Several design alternatives have been proposed for the grading in
<••Agua Hedionda Creek that address the project constraints. The Hydraulic Analysis section of
this report includes detailed discussion and hydraulic analyses of three proposed design
alternatives for maintenance of Agua Hedionda Creek.
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15 Revised: 12-12-05
HYDRAULIC ANALYSIS
The U.S. Army Corps of Engineers Hydrologic Engineering Center HEC-RAS computer
program was used to determine the hydraulic effects of the maintenance and sediment removal
from Agua Hedionda Creek based on the ultimate detained 100-year storm event.
The existing condition cross-sectional geometry is based on field surveys of Calavera Creek in
.December 2001 and Agua Hedionda Creek in May 2002. Updated cross-sectional geometry
downstream of Cannon Road is based on field surveys in June 2004. The following
improvement plans were used to model the Camion Road Bridge crossing and El Camino Real
Bridge crossing, respectively: "Cannon Road Bridge Over Agua Hedionda General Plan," sheet
59 of 131, and "El Camino Real Bridge Widen Over Agua Hedionda Channel General Plan,"
sheet 68 of 139, prepared by McDaniel Engineering (Drawing No 333-2G). Copies of these
improvement plans are included in Appendix A.
Description of Alternatives
Several alternatives for maintenance of the Agua Hedionda Creek channel within the Rancho
Carlsbad Mobile Home Park have been investigated since 1998. There are environmental and/or
community impacts within Calavera Creek and Agua Hedionda Creek that may render
maintenance within portions of the channels undesirable. However, maintenance of the Agua
Hedionda Creek channel is imperative to improving conveyance and reducing flooding in the
RCMHP. The proposed alternatives for Agua Hedionda channel maintenance are described
below. Exhibits 5, 6, and 7 show the approximate limits of grading for Alternatives A, B, and C,
respectively. A schematic of the cross-sectional geometry for Alternatives A, B, and C as well as
the 100-year floodplain limits are shown on the fioodplain alternatives map in Map Pocket 1.
The HEC-RAS workmaps are located in Map Pocket 2.
No Action Alternative
The No Action Alternative models the current channel topography within the RCMHP
and models the conveyance of the 100-year undetained ultimate development hydrology.
This alternative proposes no changes to the existing drainage patterns and is presented to
reflect the current flooding potential within the RCMHP if no channel maintenance
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
16 Revised: 12-12-05
H occurs and if none of the 4 proposed detention basins were constructed, and no
m improvements were made to the Lake Calavera outlet structure. See Appendix D for the
• No Action Alternative HEC-RAS model.
m
M Existing Condition Detained Alternative
m The Existing Condition Detained Alternative models the current channel topography
• within the RCMHP and models the conveyance of the 100-year detained ultimate
M development hydrology. This alternative is presented to reflect the potential flooding
"• within the RCMHP if no channel maintenance occurs, but assumes the 4 proposed
<P detention basins, Melrose, Faraday, BJB and BJ, are constructed, Calavera Dam
improvements are complete, the subsequent modifications to the BJB outlet structures
• have been constructed, and 500-cfs is conveyed on the north side of the wall. See
Appendix E for the Existing Condition Detained Alternative HEC-RAS model.
DM
Hg
Alternative A
"*" Alternative A models the current channel topography within Calavera Creek, and models
ta^the maintenance of approximately 2,500 feet of Agua Hedionda Creek between El
""" Camino Real and just downstream of Rancho Carlsbad Drive (HEC-RAS cross-sections
ta 10.1 to 250.86). Alternative A models the conveyance of the 100-year detained ultimate
"" development hydrology as discussed in the Existing Condition Detained Alternative.
lH
Alternative A proposed maintenance includes grading within Agua Hedionda Creek to
to
remove accumulated sediment in the channel bottom. The Alternative A channel
maintenance will require re-grading Agua Hedionda Creek back to the original
IM
trapezoidal channel geometry shown on the "Grading Plans for Rancho Carlsbad Mobile
Home Park" dated June 27, 1969 prepared by South Bay Engineering. The channel
mt
consists of 2:1 (horizontal:vertical) side slopes and a 44-foot to 58-foot bottom-width.
m
The channel will be graded down to the original channel elevation between the existing
drop structure and El Camino Real Bridge. At El Camino Real the ground elevation will
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
17 Revised: 12-12-05
., begin to "ramp" up from the original channel flowline of 31.6 feet to the existing ground
** elevation at cross-section 10.1 (elevation 35.5'). This alternative includes possible
«* complications related to the potential for continuous ponded water upstream of El
•«•' Camino Real. See Appendix E for the Alternative A HEC-RAS model.
<m
— Alternative B
"** Alternative B models the current channel topography within Calavera Creek, and models
'idj the maintenance of approximately 3,000 feet of Agua Hedionda Creek between Cannon
•i Road Bridge and just downstream of Rancho Carlsbad Drive (HEC-RAS cross-sectionsn
8.4 to 250.86). This alternative models the conveyance of the 100-year detained ultimate
m development hydrology as discussed in the Existing Condition Detained Alternative.m
m Alternative B proposed maintenance includes grading within Agua Hedionda Creek to
remove accumulated sediment in the channel bottom while protecting the mature trees
** that have established on the channel banks where possible. Upstream of the El Camino
m Real Bridge this alternative will require grading a trapezoidal channel with 2:1 side
slopes, with the top of the proposed graded slope starting near the toe of the existing
*• •channel slope. The channel grading will project down to the original channel flowline
elevation and longitudinal slope of 0.3%, with approximately a 40-foot bottom width.
Ml
Downstream of the El Camino Real Bridge to Cannon Road, the channel will be re-
graded with a 70-foot bottom width and 2:1 side slopes, to daylight. The channel«• - •
flowline will be graded at a 0% longitudinal slope from the current elevation at the
northerly edge of the Cannon Road Bridge of approximately 32.0 feet, upstream until it
meets the original Agua Hedionda Creek flowline elevation shown on the 1969 plans,«••
approximately 135 feet upstream of the El Camino Real Bridge.
pH
This alternative minimizes impacts to the existing trees within the RCMHP. However,
grading activities downstream of El Camino Real are within an area of the Local Coastal
m Plan (LCP) which is administered by the City and are subject to permitting requirements.
See Appendix G for the Alternative B HEC-RAS model.
iH
m
Prepared by: DCB:KH:kw/Report/13182-D.002
** Rick Engineering Company - Water Resources Division 12-13-04
18 Revised: 12-12-05
„, Alternative C
m Alternative C models the current channel topography within Calavera Creek, and models
m the maintenance of approximately 3,000 feet of Agua Hedionda Creek between Cannon
<i Road Bridge and just downstream of Rancho Carlsbad Drive (HEC-RAS cross-sections
MI 8.4 to 250.86). This alternative also includes widening of a portion of Agua Hedionda
• Creek between El Camino Real and the confluence with Calavera Creek to improve the
m channel capacity. This alternative models the conveyance of the 100-year detained
M|
• ultimate development hydrology as discussed in the Existing Condition Detained
III Alternative.
M ' '
"•* Alternative C proposed maintenance includes grading within Agua Hedionda Creek to
m remove accumulated sediment in the channel bottom while protecting the mature trees
Si that have established on the channel banks where possible. Upstream of the confluence
m with Calavera Creek this alternative will require grading a trapezoidal channel with 2:1
m side slopes, with the top of the proposed graded slope starting near the toe of the existing
channel slope. The channel grading will project down to the original channel flowline
*" elevation and longitudinal slope of 0.3%, with approximately a 40-foot bottom width.
tM
*" Downstream of the confluence with Calavera Creek to El Camino Real Bridge, Agua
te Hedionda Creek will be widened by approximately 27-feet to increase the channel
capacity. A vertical wall is proposed along a portion of the right channel bank (looking
MM downstream). Downstream of the El Camino Real Bridge to Cannon Road, the channel
will be re-graded with a 70-foot bottom width and 2:1 side slopes, to daylight. The
M*
channel flowline will be graded at a 0% longitudinal slope from the current elevation at
IP*the northerly edge of the Cannon Road Bridge of approximately 32.0 feet, upstream until
it meets the original Agua Hedionda Creek flowline elevation shown on the 1969 plans,
approximately 135 feet upstream of the El Camino Real Bridge.
•M . -
Alternative C minimizes impacts to the existing trees within the RCMHP. Grading
activities downstream of El Camino Real are within an area of the Local Coastal Plan
PIj. (LCP) which is administered by the City and are subject to permitting requirements.
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
19 Revised: 12-12-05
The construction of one vertical wall is required just downstream of the confluence of
m Agua Hedionda Creek and Calavera Creek (between cross-sections 30 and 20). The wall
m will be up to 10 feet high and 275 feet long along the opposite creek bank from the
m mobile homes.
<n
Ml A second vertical wall may be required to protect an existing structure. This second
m vertical wall located along the creek bank closest to the mobile homes will be up to 6 feet
<i tall and 120 feet long to preserve an existing structure.
MI
& In final design, it may be possible to implement an alternative solution to the wall(s),
m such as adjusting the property line and/or the perimeter wall location, so that the slope
•• can be extended without the need for a retaining wall. See Appendix H for the Alternative
m C HEC-RAS model.
'•
**" Bridge Improvements
*" The hydraulic analyses of all alternatives except the No Action Alternative include
"" improvements to the bridges at El Camino Real and Cannon Road. These improvements include
connecting the piers under the bridge to create one elongated pier to minimize hydraulic losses
*""" and debris potential, as well as constructing a debris nose on the upstream face of the bridge
piers to minimize the impacts of floating debris on the hydraulics of the bridge crossing.
Preferred Alternative
*"" Alternative C is the preferred alternative by the City of Carlsbad because it removes the largest
mm number of lots from the 100-year floodplain, while minimizing impacts to several of the mature
trees along the Agua Hedionda Creek channel banks within the RCMHP. Table 3 presents the
•M anticipated 100-year WSELs in Agua Hedionda Creek and the number of inundated lots for each
of the proposed alternatives.
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
20 Revised: 12-12-05
m
m
m
m
M
m
m
Table 3. Anticipated 100-year WSELs for the Agua Hedionda Creek
Grading Alternatives and Number of Inundated Lots
X-Sec
20.9
50.1
(Confluence)
70.58
120.2
170.19
210.51
250.41
No Action
Alternative
49.6
50.2
50.4
50.5
50.4
51.3
51.3
Detained 100-year WSEL (feet)
Existing
Detained
48.6
49.2
49.4
49.5
49.5
50.9
51.0
Alternative A
48.5
48.8
48.8
48.8
48.6
49.0
49.1
Alternative B
43.1
43.9
43.9
44.9
46.0
46.6
47.2
Alternative C
42.8
42.0
42.8
44.8
46.0
46.6
47.1
Approximate
Number of
Inundated Lots
Maximum
Water Depth
Above
Channel
Bank (feet)
X-Sec
50.1
X-Sec
140.65
278
7.8
6.2
225
6.8
5.1
163
6.4
4.4
33
1.5
1.1
12
-0.4*
1.1
* Although the WSEL at X-Sec 50.1 shows that flow is contained within the channel banks, the WSEL at
X-Sec 50.11 on Calavera Creek shows the WSEL above the channel banks and inundating lots near the
confluence.
m
Hi
m
m
The RCMHP consists of mainly elevated foundations. Therefore, although a lot deemed as
inundated may not necessarily mean the home is entirely flooded. The finished floor elevation of
the structure may be above the floodplain, in which case an elevation certificate may be prepared
to ensure the structure is not within the floodplain.
Prepared by:
Rick Engineering Company - Water Resources Division
21
DCB :KH:kw/Report/l 3182-D.002
12-13-04
Revised: 12-12-05
^ Additional Alternatives Investigated but not Analyzed
m The following alternatives were considered during the development of the proposed
,3, improvement alternatives. However, preliminary investigations determined several alternatives
in presented either limited flood control benefit or extensive engineering difficulties. Therefore, no
m detailed analyses were prepared for these alternatives. The following provides a discussion of
il alternatives investigated but not analyzed.
•K
M DSOD Jurisdictional Dam
m Preliminary analyses of the feasibility for construction of a DSOD Jurisdictional Dam
* upstream of the RCMHP was investigated to estimate the storage volume required to
m provide flood protection within the RCMHP. The construction of additional detention
*' basins could minimize flooding in the RCMHP area without maintenance within Agua
i" Hedionda Creek.
f" The existing hydraulic capacity of the channel was determined using the HEC-RAS
hydraulic program by modeling the existing topography in Agua Hedionda Creek with a
** series of flows until the flow was contained within the channel through most of the
If RCMHP. The HEC-RAS analyses show that the existing capacity of Agua Hedionda is
m approximately 4000 cfs.
m In order to reduce 100-year flows in Agua Hedionda Creek to approximately 4000 cfs,
along with the construction of the Melrose, BJ, and BJB detention basins currently
** proposed, the detention basin at Faraday would require an increased storage volume fromit49.8 acre-feet (currently designed) to 200 acre-feet of storage volume, and an additional
detention basin would need to be constructed within the Agua Hedionda watershed that
what would provide 895 acre-feet of storage volume. The location of this additional
detention basin is located in the vicinity of the City of Carlsbad and the City of Vista
corporate boundary. This preliminary investigation has determined that constructing two
mm
DSOD dams as additional detention facilities will result in a significant impact to
Ml
available open space, would impact not only the City of Carlsbad, but potentially the City
of Vista, and is therefore not a practical alternative.
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
25 Revised: 12-12-05
.. Levees within RCMHP
** The impact of constructing levees along the existing channel banks to increase the
*• capacity of Agua Hedionda Creek was investigated for the RCMHP project. Water
m surface elevations for the Existing Detained analysis are 5 feet or more higher than the
*« top of the channel throughout the RCMHP. FEMA requires a minimum of 3 feet of
m freeboard for levees over the 100-year water surface elevation, which would require
m construction of a berm up to 8 feet higher than the current bank throughout the RCMHP.m • •
This alternative would not be aesthetically acceptable for many homeowners within the
** RCMHP, and to construct a berm of this size assuming 2:1 side slopes would requireHi
almost a 40' wide footprint impact on each side of the channel. The construction of this
** alternative would also impact approximately 53 property owners by requiring removal of
II
their homes. Also, if similar improvements were not made to Calavera Creek several
** structures and lots would still be subject to inundation.m . ' .
** Box Culvert along El Cantino RealmAn alternative to construct a box culvert system to divert flows exceeding the capacity of
Agua Hedionda channel around the RCMHP and into Agua Hedionda Lagoon was
m
investigated. However, this structure would be required to convey approximately 3,500-
cfs and would require approximately 6 ~ 10'wide x 6' high box culverts beneath El
Camino Real for approximately 2,500 linear feet. This option is cost prohibitive and has
significant constructability issues due in part to utility conflicts.
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
26 Revised: 12-12-05
MM
ONGOING MAINTENANCE PROGRAM
Once the initial channel maintenance and grading outlined by this project has been completed, it
^ is vital that ongoing maintenance including sediment removal and vegetation removal be
performed on a regular basis to preserve the capacity of the channel and to ensure an acceptable
H level of flood protection within the RCMHP.
in
H The maintenance area will begin at the north edge of the Cannon Road Bridge and extend
approximately 2,500 feet upstream to the drop structure underneath the Rancho Carlsbad Drive
H bridge crossing. It is anticipated that ongoing vegetation removal maintenance will need to be
_ performed to ensure no vegetation becomes established between the aforementioned bridge
•N crossings.
Mi
if It should be noted, however, that the sediment deposition in the channel is directly related to
p, each rainfall event and therefore, the frequency of maintenance may be more or less frequent
H than anticipated. Monitoring of the sedimentation in the channel over the first few years
MI following the initial channel maintenance will be helpful in determining the future sediment
• removal maintenance frequency requirements. Sediment posts marked in 1-foot increments can
m be utilized in sections of the channel to assist in monitoring sediment depth. Once a depth of
*" approximately 2 to 3 feet of sediment has been accumulated, maintenance including sediment
m removal between Cannon Road and the drop structure at the Rancho Carlsbad Drive bridge
•" crossing will be needed.
<WI
m The maintenance must be performed routinely by qualified personnel and a sufficient budget
*" should be established for the maintenance. If any questions arise during the maintenance, a
""* professional engineer specializing in water resources should be consulted. The maintenance of
""* Agua Hedionda Creek must be incorporated into the environmental permitting when processed
** through the California Regional Water Quality Control Board - Region 9, the U.S. Army Corps
**" of Engineers, the California Department of Fish and Game, and the Coastal Commission if
m • .
appropriate.
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
27 Revised: 12-12-05
CONCLUSION
HI
m Agua Hedionda Creek is highly subject to sedimentation for the majority of the creek. Portions
tf of the channel within the Rancho Carlsbad Mobile Home Park (RCMHP) have experienced up to
•n 6 feet or more of sediment deposition since the original channel construction. This high
" sediment load may be the result of agricultural areas upstream of the RCMHP as well as the
m effects of an increased peak discharge within Agua Hedionda Creek due to development within
™ the upstream watershed. Because of the increased peak discharge and the accumulation of
m sediment in the channel over time, the capacity of Agua Hedionda Creek to convey storm waterII
has diminished, and currently a significant portion of the lots within the RCMHP are subject to
P inundation during a 100-year storm event. In an effort to minimize flooding within the Mobile
M
Home Park, the City of Carlsbad has investigated several alternatives to restore the capacity of
** the channel and improve flood protection in the area.
II
P Updated hydrology for the watershed tributary to the RCMHP was prepared using HEC-1 to
H determine the peak 100-year ultimate development runoff to the creeks. The detained hydrology
** for the watershed models the construction of four proposed detention basins upstream of thei .Rancho Carlsbad Mobile Home Park; two within Agua Hedionda Creek, one at Melrose Drive
m and one at Faraday; and two within Calavera Creek, BJ and BJB, near the intersection of the
m Cannon Road and College Boulevard extensions. The results of the HEC-1 analyses were
" modeled in the proposed alternative hydraulic analyses.
The implementation of the proposed maintenance alternatives for Agua Hedionda Creek includes
the following considerations: proximity of the project to the coastal zone, native and non-native
trees within the channel, environmental processing, and channel vegetation. Table 4 shows a
HI
matrix summary of the proposed alternatives presented for the maintenance of Agua Hedionda
— Creek. All of the following alternatives include the proposed ultimate detained hydrologic
conditions with the exception of the No Action Alternative.
m
m
Prepared by: DCB:KH:kw/Report/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
28 Revised: 12-12-05
Table 4. Matrix Summary of Proposed Agua Hedionda Creek Maintenance Alternatives
Alternative
Effective
FIRM
No Action
Existing
Detained
A
B
C
100-year
Discharge at El
Camino Real
(cfs)
8,080
9,195
8,092
8,092
8,092
8,092
Grading
Downstream
of El Camino
Real
No
No
No
No
Yes
Yes
Bridge Pier
Improvements
No
No
Yes
Yes
Yes
Yes
Retaining
Wall
No
No
No
No
No
Yes
Approximate
Number of
Inundated
Lots
316
278
225
163
33
12
Maximum 100-
year Water Depth
Above Channel
Bank (ft)
X-Sec
50.1
N/A
7.8
6.8
6.4
1.5
-0.4
X-Sec
140.65
N/A
6.2
5.1
4.4
1.1
1.1
HI
i
Hi
m
mm
i
i
I
m
m
m
il
Each alternative was analyzed hydraulically to determine the number of lots removed from the
floodplain. The resulting water surface elevations were mapped, and the floodplain for each
alternative is shown on the map entitled, "Preliminary Rancho Carlsbad Channel and Basin
Project 100-year Floodplain Alternatives," dated September 2004 included in Map Pocket 1.
Additional alternatives were investigated but not analyzed in detail, including: constructing a
DSOD Jurisdictional Dam, constructing levees within the RCMHP, or constructing a box culvert
along El Camino Real.
This report summarizes the maintenance design alternatives for Agua Hedionda Creek. In order
for the Rancho Carlsbad Channel and Basin Project to proceed into final design stages, the
following issues need to be resolved:
• Initiate environmental permitting through the California Regional Water Quality Control
Board - Region 9, the U.S. Army Corps of Engineers, the California Department of Fish
and Game.
• Initiate processing a Coastal Development Permit for maintenance of Agua Hedionda
Creek channel in-between Cannon Road and El Camino Real.
Prepared by:
Rick Engineering Company - Water Resources Division
29
DCB:KH:kw/Report/13182-D.002
12-13-04
Revised: 12-12-05
MELROSEBASIN
FARADAYBASIN
BASINBJ
BASINBJB
4.5
5.0
5.5
6.0 7.0BC1BC1
C2C2
AH1AH1
C4C4
AH2AH2
C1C1
AH7AH7
BC3BC3
C3C3
AH9AH9
AH6AH6
AH3AH3
AH5AH5
AH4AH4
BC2BC2
AH10AH10
DSAHDSAH
BC4BC4
AH8AH8
RRCHRRCH
RRC2RRC2
RCARCA
RCCRCC
Legend
Major Watersheds
Drainage Basins
Detention Basins
100 Year - 24 Hour 0 3,5001,750 Feet
HEC-1 100 YEAR - 24 HOURPRECIPITATION MAPHEC-1 100 YEAR - 24 HOURPRECIPITATION MAP12-8-04
c
c
c
c
c
c
c
c
Fm
MAP POCKET 1
C Preliminary Rancho Carlsbad Channel
and Basin Project 100-Year Floodplain Alternatives
C
Prepared by: DCB:KH:jflReport/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04
5 0505050
505050
606050
50 6060
60606060606050
506 0
7040
40
4040404040 40
40
40
40
40
40
4040
50
50 50505050
50
60
705050 605050606 0
6060ADMIN.EVIRDNJD O N AUEL CAMINO REAL 502501500499498497496495494493492491490489481482483484485486487488480479477476475474453454455456457458503
504 473472471470469468467466459460461462463464465452431432433434451450449448447446445444443435436437438439440441442430429428427426425424423422421420419418417416415
406407408409410411412413414398397399400401402403404405396395
394
393
392
391
390
389388387386385384383382381380379
378
377
376
375
374
373
372371370
369
368
367
366
365
364
363
362
361
360359358357356355354353352351350349348347346345344
343
342
341
340
339
338
337
336
335
334
333
332
331
330
329
328
327
326
325
324
323
322
321
320
319
318
317
3163153143133123113103093083073063053043033023013002992982972962952942932922912902892822812882872862852842832802792782772762752 7 4
273272271270269268267266265251252253254255256245257258259260261262263264250249248247246244243242241240239238237236235234233232231230229228227226225224223222221220219218217216215214213212211210209208207206205204203202
201 200199198197196195
194193
192191190189
188187186185184183182137
13513413312213121110987654321181180179178177176
175
174
173
172
171
170
169
168167166165164163162161160159158157156155154153152151150149148147146145144143142141140139138
1361321311301291281271261251241231211201191181171161151141131121111101091081071061051041031021011009998979695949392919089888786858483828180797877767574737271706968676665646362616059585756555453525150494847464544434241403938373635343332313029282726252423222120191817161514RANCHO CARLSBAD DR.RANCHO CARLSBAD DRIVERANCHO CARLSBAD DRIVEDON VALDEZ DRIVE
DON MIGUEL DRIVE
DON RICARDO DRIVE
C A L A V E R A S D R IV E
D O N R O D O L F O D R I V E
DON ALVAREZ DRIVEDON RICARDO DRIVE
DON MIGUEL DRIVE
DON MATA DRIVEPIPE
CALAVERAS DRIVEDON MATA DRIVEDON JUAN DRIVEDON LORENZO DRIVEDON JUAN DRIVEDON ORTEGA DRIVEPIPEDON ALBERTO DRIVEDON CARLOS DRIVEDON CARLOS DRIVE
DON FELIPE DRIVEDON JUAN DRIVEDON ORTEGA DRIVEDON LORENZO DRIVEDON ARTURO DRIVECALAVERAS DRIVEDON LUIS DRIVE
DON PABLO DRIVEDON QUIXOTE DRIVED O N D IA B L O D R IV E
DON TAMASO DRIVEDON PORFIRIO DRIVED O N A L V A R E Z D R I V EDON COTA DRIVEDON RICARDO DRIVE
DON MIGUEL DRIVEDON JOSE DRIVELAKECREEKDON JUAN DRIVEDON CARLOS DRIVE478RECREATIONAGUA HEDIONDA CREEK DON CARLOS DRIVECALAVERACLUB HOUSE6050708060
60606 0
606070
70708080
8 08 080909 0909090100
1001001 0 0
100110110110120120EL CAMINO REAL R.S. 1800-1
A R E AGARDEN IN G
STORAGE AREA STORAGE AREARECREATIONAL VEHICLEPROPOSED120120110110110100100100100909090901009080808080807070706060606060
601201101 0 0
1009 0
9090 808080
8080
70
7070
7070
6 0
6060
606060606060
606060606060
50
50 60120110110
10090
908 0
8 0
1 20110
110
110100100100100100
100
100 90909090
90
90 808080808080
70707070
70606060 10011 0
1 20
13 0
70 N COMPILED BYPHOTOGRAMMETRIC METHODSFROM AERIALPHOTOGRAPHYDATED -CONTOUR INTERVAL -APPROX. PHOTO SCALE -JOB NO. -HORIZ DATUM -VERTICAL DATUM -NGVD 29NAD 83GRAPHIC SCALE. 1"=40'04080120 RANCHO CARLSBADCALAVERAS CREEKDETENSION BASIN DESIGN11/25/982 FT.1" = 250'13182A34.8 34.634.7
3 4.835.0
3 4.9
3 5 .134 .73 4 .935 .03 5 .435 .434 .433.6 33.9
33.7
3 3 .13 3.1
3 3 .433.6 33 .733 .93 4 .43 4.3
3 4 .23 4 .43 3 .93 3 .93 3.9
3 4.6
34 .134.3
3 3 .934 .442.7
4 3.643.640.2 40.9
37 .03 7.3
3 5 .83 5 .73 6.2
35.6
3 7 .437 .63 7 .13 7.9 37.536.2
35.7 36.4 3 6.5 3 6 .638 .337.0
3 5 .535.9 36.136.138.1
3 7 .937 .837.6
3 7.4 38.2
3 7 .83 7 .937.937.7
39.4
3 9 .64 2 .64 3.4
40 .14 0.9
3 8 .83 8 .63 9 .638 .93 9.7
3 9 .63 9 .83 9.8 41 .240.9 40.7
4 0 .840 .943.1 41 .94 1 .441 .942.7
43.1
4 3 .54 3.6
4 3 .64 3.6 43.6
4 3 .54 3.2
4 2.9
43.1
43.4 43.5 4 3 .64 3.7
4 3 .543.4
43 .14 3 .44 3 .443.443.443.742.9
4 3.7
43.4
4 3 .743 .343.8
4 3 .643.0
43.1
4 3 .539.1
3 8 .738.7
38 .63 8 .54 1 .141.3
4 1 .03 9 .63 9 .33 9 .138.739.443 .24 3 .44 3 .74 3 .543.643.343 .541.941.941 .74 1 .44 1 .542.6
43.5
4 3 .742.9 43 .44 2.9
41.9
4 1 .94 1 .942.343.7
42.9
4 3 .141.6
41.6
3 9 .739.5
3 9 .940.5
4 1.0
4 3.1
4 3 .64 5.8
51 .351.5
4 5.8
4 8 .951 .44 9 .44 7 .947.3
4 8 .34 6 .845.7
4 5 .947 .646.9
46.5 46.1
47.2
4 6 .252 .15 1.9 51 .35 1.1
4 5.644.5 47 .350.1
4 9.451.7
50.9 5 1 .65 1.4 51 .55 1 .949.2
51.747.849.04 4.9
4 4 .94 4.8
45.0
4 4.5
44 .545.144.644.6 45.6
4 5.244.9
4 4 .64 4 .64 5.2 45.2 44.7
45.3 45.444.6 45.2
45.5
45.8
4 5 .54 4 .845.7
4 4 .74 4 .745.2
4 5 .74 5.0
4 5 .445.6
4 4.944.844.544.6 4 5 .045.2 45.6 45.8
4 5 .64 6 .947.1
45.945.846.2
45.9
4 5.9
4 6 .845 .846 .24 6 .346.8 46 .946.7 4 7.247.3
4 5 .947.1
4 7 .146.6 47 .24 6.8
4 7.1
47.046.545.1
45.0
45 .245.6
4 5 .345 .14 5.2
4 5.1 45.3
45.3 45.5
44.6
4 5.0 45.1
45.6
4 5 .44 5 .14 5 .445.1
4 5 .44 5 .245 .24 5.8
47 .046 .44 5.9
4 5 .946 .747.2
4 6.5
4 7.3
46.9 47.2
4 7 .046.6
46.3
4 5.9 46.3 45.9 4 5.9
4 5.6
4 5 .64 4.745.245.545.6
4 5 .045.1 47.2
45 .946.8
46.5
4 7 .047.046.9 4 6 .54 6 .44 6 .747.2
4 5 .94 6.9
4 8.7
4 8.6
4 8.147.848.7
48.3
4 7 .94 7 .44 7.6
47.4
4 9 .04 8.8
4 7 .94 7.6 47.347.747 .34 7 .44 7.7
47.7
4 8 .44 8 .848 .448.748.347.6 47.6
47 .44 7.9
4 8 .447.4
47 .547.8
4 8.6
49 .449 .849.1
5 0.2
4 9 .150 .24 9 .54 9.1
4 9 .448.8
5 0 .249.9
4 9.9
4 8 .84 9 .34 9.9
4 9.3
49.047.747 .548.748.4 4 8 .347 .947 .34 7 .547.7
4 7 .34 7.6 47 .848 .44 8 .749.0
4 9 .94 9.0
49.449.249.0
5 1.151.0 50.750.7 51 .750.5 51 .05 1 .051.1 51.1
51 .15 0 .550 .65 1.050.6
5 0 .646.9
4 9.4
5 1 .25 1 .05 1 .95 0.3
51.1
5 0 .651 .84 9 .45 1 .05 1 .15 0.2 50.450.450.4
49.7
4 9 .549 .44 9 .951.9
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50.5
5 0 .15 1 .25 1.650.2 51.3 5 0.9
5 1 .151.2
5 1.0
50.8
5 0 .65 0 .550 .45 1 .65 1 .651.6
5 1.3
5 1 .251 .251 .948 .55 0.150.3
5 1 .451.7
48.5 48.9
4 9.2
48 .749.0
4 9 .65 0 .65 1 .35 1.351.94 9 .549.2
4 9 .74 5 .044 .744 .94 5 .845.9 45.9
4 4.9 45.4 45.845.4
44 .947.0
4 7 .24 5.9
4 5 .947.9
4 7 .64 7 .847.3
4 8.1
4 8.7
49 .44 9.4
49 .849 .348.9
4 9.3
4 8.9 49 .05 0.850.3
51.2
50.7 45.0
4 5 .54 6.5
5 1 .44 6.6
4 7 .447 .848.1 48 .44 8 .84 9 .249.4
4 9 .64 9 .65 2 .15 0.6
5 1.0
5 1.651.3
50.7 50.750.750.7
51.9
4 3.94 3.94 3.8
4 3.943.9
43.9
43.9
4 3.9
43.9
4 3 .84 4 .24 3 .944.3
4 4 .444 .44 4.44 4.4
4 4.444.44 4 .444.3
4 4 .34 4 .24 4.4
44.3
4 7 .051 .84 7 .051 .845 .145 .147 .947 .952 .152.160.260.2
5 7 .85 8 .35 8.2
59 .158.4
5 7.9
5 7 .55 7 .65 6.7
57.1
5 6.9
5 6.257.1 59.157.255 .75 5.3
57 .456 .955 .15 5.65 6.359.6
54.5 55.6
55 .255.9
5 6.1 57.1
5 7.155.8
5 6.3
5 6 .456.6
5 9 .158 .857.0
5 9 .05 7 .957.3
54 .554 .95 6.7 56 .85 5.55 7 .55 8.3 57 .158.957.3 59 .159.6
5 9 .15 7 .55 7 .657.157.45 7.1 56.658.85 7 .95 6.35 5.658.9
57 .15 8.3
5 7 .55 5.559.6
5 8.658.858.558.1
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57.0
5 7 .557.8
58.2
58.7
58.9
5 9 .259 .35 6 .656.4
57.0
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5 8 .95 9 .55 9.258.557.65 8.9
5 9.2
59 .85 7 .157 .15 9 .16 0.1
5 5.1 58.8
5 7.6
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5 9 .95 9.25 9.358.8
57.4
5 7 .557.3 57.5
6 0.2
6 0.455 .95 6.3 56 .857.4
5 7.6
57 .85 7 .557.3 57.5
6 0.2
6 0.460 .360.3 59.5
60 .460 .360 .36 0.2
60.3
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5 9.25 9.3
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5 9 .958.8
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6 0.260.360 .360 .459.5
60.3
60 .36 0.46 0.2 57.5
57.3
5 7 .557.4 58.8
59.3
5 9.2
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57 .85 7.6
58.8
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59 .85 8.658.858.558.1
56.6
57.0
5 7 .557.8
58.2
58.7
58.958.65 9 .058.5
5 8 .95 8.9
5 9 .259 .359 .959.6
5 9 .55 9.2
5 9 .16 0.157.357.0
5 8.5
57.1
5 7 .855.3
54.9
5 4 .556 .65 5.7
55.6
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5 5.5 55.6 55 .655 .455.3
5 4 .45 5.3
5 5 .657.4
5 8 .65 8 .65 8 .657.4
5 5 .655 .05 4 .45 5.3
5 4.7
5 5.3 54.7
55.5
5 5.5
54 .654.5
54.5 54.4
54.956.6 56 .95 6 .45 6 .15 6 .75 5 .355 .154.856.8
5 6 .556.8 56 .956 .65 6 .15 5.6
5 5.8
5 5.7
5 5 .95 8 .25 8.4
57 .15 7.4 58.7
5 8.2
5 7 .35 8.6
5 8 .257.6
5 7.8
57.1
5 7 .159.2
5 8.8
5 9 .459.2
5 9 .45 8.8
5 9 .45 8.85 9.2
5 8.6
5 8.2
5 7.8
5 8 .254.7
5 4 .354.4
5 5 .154 .55 4 .95 5 .95 5 .655 .25 6 .15 6 .956.5
5 4 .85 7 .45 5.7 57.8
56.1
57.455.9 5 4 .855.1 55.8
5 5.7
55.2
5 4 .755 .155 .75 5.5
5 5 .15 4.8 54.7 55 .654.8
5 5 .85 7.556.5
5 5.7 56.9
56 .856.354.9
56.957.3
5 7.3 58.159.25 8 .95 8 .958.6
5 7 .657 .35 7 .658.8
5 8.5
5 8 .358 .759 .25 8.9
58 .558.3
5 9.1
59.1
5 7 .75 9.5 59.5
5 9.4
5 9.5
5 9 .859.3
5 9.8
5 9 .65 9 .555 .654.8
5 5 .854.9 55.6
5 7.558.158.6
56.9
56 .856.357.35 7 .65 8.5
5 8 .358 .558.3
5 7 .759 .25 8 .95 9.5
5 8 .958.859.5
5 9.4
58 .759 .25 9.5
5 9 .859.3
5 8.9 5 9.8
5 9.1
5 9 .65 9 .559.1
5 9 .55 9 .65 9.8
59.3
5 9 .85 9.5
5 9.4
59.5
5 9.5
5 7 .759.1
5 9.1
58.3
58 .55 8.9
59 .258 .75 8 .35 8.5
58.857.657 .35 7 .658.6
5 8 .95 8 .959 .258.156.9 55.6
54.9
56.356.856.9
5 5.756.5
5 7.5 5 5 .854.8
55 .654.755.755 .15 4 .757.854.7
5 6.8 56.1
56.2
5 7 .45 8.558.558.5
56.1
52.8
5 2.354.2
5 2 .352 .452.7
5 2 .45 3 .15 2 .452 .152 .253.6
53.653.152.4 53 .45 2 .752 .353.7
53.1 53.853.7
53.2
5 3 .053.0 53 .153.2
5 3 .953 .053.6 5 4 .353.9
54.352.75 2 .95 3.4
5 4 .352.552.75 2.7
52 .75 2 .252.4
5 2 .75 3 .25 3.2 53 .35 3 .55 3 .55 3.4 53 .95 2 .65 2.4
5 3 .35 3 .454.1
5 3.7
5 3.4
5 2 .153.3 53.7
5 2.453.853.5
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5 2.7
5 2 .552 .352.7
5 2 .353 .15 2.5 5 3.6
5 2 .953 .35 2 .653 .953.0
5 3 .45 3 .45 3 .45 3.9
5 9.5
5 8 .75 9.5
5 8 .758.8
57.957.8
5 9.0
5 8.658 .45 9.0
58.8 57.8
5 8.658 .457.9
5 9.7
5 9 .359 .455.0
5 5.3
5 7.0
5 7 .357 .057 .358.1
5 8 .35 9.7
5 9 .359 .45 7.0
5 7 .357 .057 .358.1
5 8 .355.0
5 5.3
55.3
5 5 .055.1
56.458.7
59 .059 .058.7
59.9
59 .058 .859 .859.6 59.7 59 .558.9
59.559.259 .05 9 .159.1
60.2
5 8 .960.4
5 9 .359 .559 .659 .55 9 .159.1
5 8 .858 .858.959.059 .859.759.559.259.959.6
60.2
60.4
5 9 .359 .05 8 .959.0
5 8.558.2
58 .758 .559 .15 9 .658.9 58 .958 .658.7 5 9 .159 .15 8 .558.4 59 .158.4
5 8 .15 8 .458.3
5 8 .65 8 .757.657.4
5 7 .75 7.7
57.6
5 7.5
5 8 .35 8 .15 8 .55 7 .859.1
5 9.5
5 9 .159 .159 .159.0 58 .858 .958 .658.7
59 .15 9 .65 8.558.2
58 .758 .558.958.4
58.4
5 8 .15 8 .553 .95 2.953.95 2.9
5 3 .453 .953 .153.3 53 .95 3 .453.3 53 .15 3 .95 3 .952.761.8
6 2 .161.8
6 2 .160 .960 .96 4 .666.5
6 4 .666.5
6 1.8
6 1 .46 1 .46 1.8
6 1 .761.4
61 .461.8
62 .362.5
60 .960.8
6 1 .360 .960.5
6 0 .56 0 .660.7
60 .760.7
60.860.96 0 .56 0 .660.760.860.7
60 .760.7 60 .560.760.6
6 0.6
6 0 .66 0.5
6 0 .56 0 .960 .560 .660.5
6 1 .36 2 .46 1.9 61 .463.1
62.2
6 2 .26 2.9
61.6
6 1 .76 2.162 .26 1.863.563.3
6 3 .06 3 .063.3
63.5
6 1.862 .26 2.16 2.9
6 2 .262.2 63.1
6 1.962.460 .56 1 .76 0 .96 0 .561.661.46 0.5
6 0 .66 0.6
60.6 60.7
60 .560 .860.7
60 .660.7
60 .760.7
6 0 .66 0 .560.560.96 1 .360.8
6 1 .761.8
62 .362.561.4
61 .460 .96 0 .56 0.7
6 0 .66 0 .46 0 .66 0 .76 1 .560 .76 1 .06 0 .56 0.7
6 0 .66 0 .46 0 .66 0 .760 .76 1 .06 1.2
6 1 .56 1 .060 .76 1 .56 0 .76 0 .66 0 .46 0 .66 0.7
6 0 .56 1.2
6 7.167.1
6 4 .967 .46 4 .86 5 .064.5
6 5.3
6 5 .06 4.5
6 5.1
6 4.46 4.564.5
6 4.46 5.1
6 4.5
6 5 .06 5.3
64.5
6 5 .06 4 .867 .46 4 .96 7 .06 6 .466.5
6 7 .066.5
6 6 .460.760.7
62.1
6 2 .761.961.060.9
61.6
6 0 .562 .96 3 .063 .161.961.6
61 .060.9
6 0 .562.1
6 2 .763 .16 3 .062 .960.460.4
6 0 .86 0 .86 0.8
6 0.7
6 0 .560.5
6 1 .461 .06 0 .96 3.5
6 1.2
6 1 .863 .96 1 .86 3.5
63 .96 1.2
6 0 .96 0 .86 0 .86 0.8
6 0.7
6 0 .560.5
6 1 .461 .062.3
6 3 .763.6
62.4
62.6
61.7
6 2.5
62.3
6 3 .763.6
62.4
62.6
61.7
7 3 .37 1 .112 0.5120.5
Preliminar y Rancho Car lsbadChannel and Basin Project100-year Floodplain Alter natives
0 200 400 600 800100Feet
NOT TO SCALE
I
MAP POCKET 2
HEC-RAS Workmap
L (Available on Request)
C
c
c
c
E
G
Prepared by: DCB:KH:jffReport/13182-D.002
Rick Engineering Company - Water Resources Division 12-13-04