HomeMy WebLinkAbout3537; Vista/Carlsbad Interceptor Sewer; North Agua Hedionda Interceptor; 2003-07-24Geotechnical Engineering
Geology
Hydrogeology
Coastal Engineering
Hydrology
Hydraulics
Project No. 2181
July 24, 2003
Mr. Edward Matthews, Sr. Engineer
DUDEK & ASSOCIATES
605 Third Street
Encinitas, California 92024
WAVE UPRUSH STUDY
NORTH AGCIA HEDIONDA INTERCEPTOR
ACCESS ROAD & SHORELINE PROTECTION
CARLSBAD, CALIFORNIA
Dear Mr. Matthews:
TerraCosta Consulting Group, Inc. (TCG) is pleased to present the results of our
wave uprush study for the preferred CIDH wall alternative for stabilization of the
proposed sewer access roadway adjacent to the northerly shores of Agua Hedionda
Lagoon, generally southerly of Adams Street, extending from Hoover Street easterly
a distance of 1,800 feet, within the City of Carlsbad, California (Figure 1).
This report addresses the Coastal Commission's requirements as outlined in their
December 31, 2002, letter, in which they requested a wave uprush study for the
subject project, including calculations and a short letter-report summarizing the
assumptions used and the conclusions of the wave uprush study.
In summary, wave runup results from wind-driven waves within Agua Hedionda
Lagoon, which are both fetch- and depth-limited. In evaluating wave runup, wind
speeds ranging from 20 to 60 mph were considered, with the design wave height
ranging from 0.8 to 0.9 foot, with a design period of 1.3 to 1.4 seconds. For these
conditions, the maximum wave runup is approximately 2 feet above the design still
water level, reaching a maximum design elevation of approximately 7 feet MSL, or
well below the minimum top-of-wall elevation. The wind and wave environment,
along with the assumptions used in developing the wave runup, are discussed
below.
4455 Murphy Canyon Road, Suite 100 A San Diego, California 92123-4379 A (858) 573-6900 voice A (858) 573-8900 fax
DUDEK & ASSOCIATES July 24, 2003
Project No. 2181 Page 2
COASTAL WIND REGIME
Normal wind conditions in the coastal San Diego region originate from the
northwest due to the eastern North Pacific high. This high is dominant in summer,
but usually moves south and weakens in winter. Winter winds are also primarily
from the northwest, but are modified by passing storm fronts and other
meteorological disturbances. East and southeast winds are common as cold fronts
approach and often veer south or southwest with the passage of storms (CCSTWS
85-7).
An important climatic feature in the area are the Santa Ana winds that can develop
at any time of the year, originating from high pressure centers, which develop over
the Great Basin, often a day or so after the passage of a cold front. In winter, the
winds are generally cold and can extend over 100 miles seaward (CCSTWS, 85-7).
Typical wind speeds in canyon areas are on the order of 20 to 30 mph, but severe
winds, which are not unusual, can attain speeds of over 90 mph. Although Santa
Ana winds within the L.A. Basin typically originate from the northeast, strong winds
associated with Santa Ana conditions can still approach San Diego's north county
coastline from the southwest (DeMarrais, et al., 1965, CCSTWS 85-7). Average
wind speeds along San Diego's north county coastline are about 6 mph. Winds
exceeding 17 knots occur approximately 1.6 percent of the time, and winds
exceeding 27 knots occur approximately 0.02 percent of the time. The maximum
peak wind gust measured in the San Diego region was recorded at 63 mph
(Qoodridge, 1979, CCSTWS 85-7). The San Diego north county coastal wind speed
probability exceedance is shown on Figure 2.
LAGOONAL WIND-GENERATED WAVE ENVIRONMENT
As indicated in Figure 1, the proposed wall alignment runs along the northerly
shores of Agua Hedionda Lagoon, with a maximum fetch ranging from 1,200 feet to
1,400 feet from winds out of the west-southwest to the south-southwest,
respectively.
DCJDEK & ASSOCIATES July 24, 2003
Project No. 2181 Page 3
Agua Hedionda Lagoon is relatively shallow, with a fairly consistent lagoon bottom
elevation throughout most of the western portion of the eastern basin, with the
lagoon bottom elevation ranging from -4 to -6 feet, MLLW Datum (personal
communication with Kevin Cull - Merkel & Associates). The water surface elevation,
and hence the design stillwater level (SWL), is a function of tidal elevations
attenuated by the lagoon entrance channel, with a reasonable approximation being
the hydroperiod function for the Maximum Tidal Basin Plan for the San Dieguito
Lagoon Restoration Project developed by Dr. Scott Jenkins Consulting for Southern
California Edison (August 1999). This hydroperiod function, which was developed
for the San Dieguito Lagoon Restoration Project and is reproduced herein as Figure
3, includes all of the meteorological conditions that affect water surface variations
along San Diego's north county coastal environment for a similar-sized basin
controlled by a maintained lagoon outlet. When using Figure 3, please note that
0 MLLW = 2.56 feet NGVD = 2.75 feet MSL.
Wind-driven waves within Agua Hedionda Lagoon are both fetch- and depth-limited.
Nomographs for wave period and wave height are presented for both 5- and 10-foot
design water depths in the U.S. Army Corps of Engineers Shore Protection Manual
(SPM), 1984 Edition. For wind speeds of 60 mph, the design wave height ranges
from 0.8 to 0.9 foot, with a design period of 1.3 to 1.4 seconds. As indicated in the
SPM nomographs, waves with wave periods less than 1.4 to 2 seconds
[corresponding to 5 to 10 foot water depth] are considered to be deep-water waves,
i.e., d/t2 < 0.78.
In evaluating wave runup, we considered wind speeds ranging from 20 to 60 mph,
and a water depth at the base of the structure ranging from 0 to 6 feet. We also
addressed deep-water wave heights ranging from 0.3 to 0.9 foot, corresponding to
wave periods ranging from 0.9 to 1.4 seconds. For these conditions, the maximum
wave runup is approximately 2 feet above the design stillwater level reaching a
maximum design elevation of approximately 7 feet, MSL, or well below the
minimum top-of-wall elevation. Please note that the probability of occurrence of a
given lagoon elevation and wave-generating wind would be the combined probability
of Figures 2 and 3, with the joint probability being the multiplication of the two.
Supporting calculations are included in Appendix A.
DCJDEK & ASSOCIATES July 24, 2003
Project No. 2181 Page 4
We appreciate the opportunity to be of service and trust this information meets your
needs. If you have any questions or require additional information, please give us a
call.
Very truly yours,
TERRACOSTA CONSULTING GROUP, INC.
Walter F. Crampton, Principal Engineer
R.C.E. 23792, R.Q.E. 245
WFC/jg
Attachments
(6) Addressee
DUDEK & ASSOCIATES July 24, 2003
Project No. 2181 Page 5
REFERENCES
Cull, Kevin, June 2003, Merkel & Associates. Personal communication.
DeMarrais, G.A., Holzworth, G.Q., Hosier, C.R., 1965, Meteorological Summaries
Pertinent to Atmospheric Transport and Dispersion over Southern California,
G.S. Weather Bureau, Tech Paper 54, 86 pp.
Qoodridge, J.D., et al., 1979, Windstorms in California, California Department of
Water Resources, Sacramento.
Jenkins, Scott A., et al., August 30, 1999, Hydroperiod and Residence Time
Functions for Habitat Mapping of Restoration Alternatives for San Dieguito
Lagoon.
O.S. Army Corps of Engineers, December 1985, Meteorological Data Inventory,
Southern California Coastal Zone, Coast of California Storm and Tidal Wives
Study, CCSTWS 85-7.
U.S. Army Corps of Engineers, 1984, Shore Protection Manual, Coastal Engineering
Research Center, Vicksburg, MS, Vol. I and 11.
Proposed Project Alignment \
TERRACOSTA CONSULTING GROUP
1i35
1
FETCH LENGTH: 12OO' WSW
140O' SSW
WIND SPEED: KEF CCSTWS 85-7
AVERAGE WIND SPEED: 6 MPH
AVERAGE SPEED FROM WSW: 6.3 MPH
A VERAGE SPEED FROM SSW: 6.0 MPH
% ABOVE 17K: 1.6 (19.5MPH)
% ABOVE 27K: O.O2 (31.OMPH)
PEAK GUST: 63 MPH
60-
40-
2O-
o
O
50
PERCENT TIME EXCEEDED
100
WA TER LEVEL IN LAGOON:
ASSUME SAME HYDRO-PERIOD AS THE SAN DIEGITO LAGOON
MAXIMUM TIDAL BASIN PLAN ALTERNATIVE - SEE ATTACHED.
NOTE: MLLW = 2.56' NGVD = 2.75'MSL
.'. 5'NGVD = 5.19'MSL
SOURCE: CCSTWS 85-7
TERRACOSTA CONSULTING GROUP
ENGINEERS AND GEOLOGISTS
44SS MURPHY CANYON ROAD. SUITE 100
SAN DIEGO. CA 92123 I858I 573-8800
PROJECT NAME
NORTH AQUA HEDIONDA INTERCEPTOR
FIGURE NUMBER
PROJECT NUMBER
2181
WIND SPEED EXCEEDANCE
Figure 4: Hydro-period Function8: Maximum Tidal Basin Plan
San Dieguito Lagoon, CA
Existing Conditions
Maximum Tidal Basin Plan
Frequentiy Exposed Mud Flat
Frequently
Flooded
Mud Rat
Q
§
C 2 —
O
I.2
HI
8 0-
D)CO
0 50
Percent Time Exposed
aBased on habitat delineation from Josselyn and Whelchel (1999).
100
SOURCE: JENKINS. JOSSELYN & WASYL,
3OAUGUST 1999
TERRACOSTA CONSULTING GROUP
ENGINEERS AND GEOLOGISTS
4155 MURPHY CANYON ROAD, SUITE 100
SAN DIEGO. CA 92123 I858I 573-6900
PROJECT NAME
NORTH AQUA HEDIONDA INTERCEPTOR
FIGURE NUMBER
PROJECT NUMBER
2181
HYDRO-PERIOD FUNCTION
APPENDIX A
CALCULATIONS
Figure 4: Hydro-period Function8: Maximum Tidal Basin Plan
San Dieguito Lagoon, CA
Existing Conditions
Maximum Tidal Basin Ran
Q3
O
I
LLJ
C
5 —
3 —
2 —
8 o-O)
-1 —
o
EHVy=+5.pft
z="+4.9*n
Z = +3.9ft
::::::::£Tran$WoHat:
High Marsh
= +2.4tt
o>
z=+i.2ft
-ft
-2.0ft
Subtidal
Frequently Exposed Mud Rat
Frequently
Flooded
Mud Rat
co
CM
50
Percent Time Exposed
I
100
"Based on habitat delineation from Josselyn and Whelchel (1999).
U)
Itot.i WVM U a Mitt «•»«» »f S fMt Witt MV* p******
1.4
ISO
I 1.5 2253 4-5678910 1.5 22.53 4 5678910 1.5 22.53 4 56789)0 1.5 22.53 4 5678910
XIOO X 1,000 X 10,000 X 100,000
Fetch (fl)
Rote Ornt to • MM* 4«tl> •< '•' •*!•« irttti IMM
1.4 •*««i4i m <e«iU*n4 te
!•» th«n
, '/i > 0.78.
<0.75 n
•0.50m
H»0.25m
I 1.5 2 3 4 5 6 8 10 1.5 2 3 4 5 6 fl 10 1.5 2 3 4 5 6 S 10 1.5 2 3 4 0 6 8 10
XIOO X! 000 X10 000 XIOO 000
F»leh-F (m)
Figure 3-27. Forecasting curves for shallow-water waves; constant depths •» 5 feet (upper graph)
(lower graph). V ,\ .;.;;••;/_ L „.,&,«.»•., A 4a. ^.. «L.i» *_ .., .
u>
I 1.5 22.5* 4 5678910. 1.5 22.53 4 5678910 1.5 22.53 4 5678910 1.5 2253 4 5678910
XIOO X 1,000
»«t«i M*TM 1* * mm 4*»th •( 1.0 MUM with «m M'ted' 1«> thin
Fetch (ft)
X 10,000
m «atliU«<4 to k< <<4|w<(ir ««v««, !.«., */ 1 > 0.78.
X 100,000
I 1.5 2 3 4 S 6 8 10 I.S 2 3 4 S 6 8 10 1.9 2 3 4 S 6 S 10 1.5 2 3 4 9 6 a 10
Figure 3-28. Forecasting curves for shallow-water waves; constant depths - 10 feet (upper graph)
and 3.0 meters (lower graph).
Point of maximum wave runup
Figure 7-7. Definition sketch: wave runup and overtopping.
shown in Figures 7-14 through 7-18. Effects of using graded riprap
face of an impermeable structure (as opposed to quarrystone of uniform
for which Figure 7-15 was obtained) are presented in Figure 7-19 for a 1
graded riprap slope. Wave rundown for the same slope is also present*
Figure 7-19. Runup on permeable nibble slopes as a function of strucl
2 ?2
slope and H'/gT is compared with runup on smooth slopes in Figure 7-3
Corrections for scale effects, using the curves in Figure 7-13, should|
applied to runup values obtained from Figures 7-8 through 7-12 and
through 7-18. The values of runup obtained from Figure 7-19 and 7-203
assumed directly applicable to prototype structures without correction
scale effects.
As previously discussed, Figures 7-8 through 7-20 provide design c«
for smooth and rough slopes, as well as various wall configurations,
noted, there are considerable data on smooth slopes for a wide range of d'
values, whereas the rough-slope data are limited to values of d /H' >3 *\
is frequently necessary to determine the wave runup on permeable
structures for specific conditions for which model tests have not
conducted, such as breaking waves for d /H' < 3 . To provide the necesc
design guidance, Battjes (1974), Ahrens (1977a), and Stoa (1978) have
gested the use of a roughness and porosity correction factor that allows
use of various smooth-slope design curves for application to other struct
slope characteristics. This roughness and porosity correction factor,
is the ratio of runup or relative runup on rough permeable or other nonsmoojj
slope to the runup or relative runup on a smooth impermeable slope. This<
expressed by the following equation:
7-18
0.15 0.2 0.3 0.4 0.50.6 a8 1.0
Slope (cot 6)
1.5 2.0 3.0 4.0 5.0 6.0 8.0 10.0
Figure 7-8. Wave runup on smooth, impermeable, slopes when de/H£ = 0
(structures fronted by a 1:10 slope).
7-19
O.I 0.15 0.2 0.3 0.4 05 0.6 0& 1.0 1.5 2.0 3.0 4.0 5.0 6.0 8.0 10.
Slope (COt 6 )
Figure 7-9. Wave runup on smooth, impermeable slopes when d /H' « 0.45
(structures fronted by a 1:10 slope). 8 °
7-20
0.3 0.4 0.50.6 0.8 1.0 1.5 2.0
Slope (cot6)
4.0 5.0 6.0 8.0 10.0
re 7-10. Wave runup on smooth, Impermeable slopes when d /H" « 0.80
(structures fronted by a 1:10 slope). e °
7-21
""-"""""•"""•- • - • " rr................... ...............111............ ......... .MllillllO.I .0.15 0.2 0.3 0.4 O.S 0* 0.7 0.80.91.0 1.5 2.0 3.0Slope (cot 0)4.0 5.0 6.0 7.08.09.010 IS 20 30 40 50
(Jo.lll., I
O.I O.IS 0.2 0.3 0.4 0.5 0.60.70.80.91.0 1.5 2.0 3.0 4.0 5.0 6.0 7.0 &0 9.0 10 15 20 30 40 50
Figure 7-12. Wave runup on smooth, impermeable slopes when d_/H' 2: 3.0 .
to H
6.0
5.0
4.0
3.0
2.01
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•••"•••^••MVVBWWWVqlHraHMB ••hit ••*II^VM«H<IBMMBMil*W^«» r^"* •••••»••! I mmwmmvmm lltlftlMIBR• •••••• ••iiii«i«»irtiii»»l«»iiii.-«m«i«"«"••••• ••••"ik:i i»»vr"«nmil••••• 1111111111 ••<«»>"BBKaiiiiliili|iiBiiBpll>illlij-i •••••••• •••••I. v-il ll>>..--<i>B»i li-"l inn ••
IBiBlBI>«BBB«lllll1IIIIIBBBIIIIIIIIIIII*lk.1BBI»Bi«iBlBlBrV>ll>-<lllllll ••••..;-•! ill!! ••
•••••••••••••••••tiiMmn••••• wr*mmmmmmfn:**A 411101__...^ v____«i > «i •« mini••• ii •••••••••« HIIIUI n
IHIIintlllllllM
I en 10 tlep*
Vertical Wall
0.00004 0.0001 0.0002 0.0004
See Figure 7-13,correction (or
model scale effect.
0.001
H'o
Tr5
0.002 0.004 0.01 0.02
(after Seville, 1956)
2
Figure 7-14. Wave runup on impermeable, vertical wall versus H'/gT .
-7-24. Overtopping parameters a and (K (smooth vertical wall on a
1:10 nearshore slope).
7-A5