HomeMy WebLinkAboutC-2287 - 208 Water Quality Plan Program, Interim Early Action Plan208 PLANNING
NEWPORT BAY WATERSHED
Enclosed is a report on Sedimentation Analysis which is a part of the
San Diego Creek Comprehensive Stormwater Sedimentation Control Plan. This
Report identifies the sources of sediment and estimates the quantities and
types of sediment that will deposit in Upper Newport Bay under existing and
ultimate land use conditions.
The information contained in this Report is being used by the Consultant,
Boyle Engineering Corporation, to develop the comprehensive plan. A report on
the proposed plan will be caTleted shortly and public hearings will be held
starting in November.
The Planning Advisory Caimittee, which was appointed by the City Council's of
Irvine and Newport Beach to review the Consultant's work, has scheduled a
public review of the enclosed Report for 7:00 p.m., Thursday, July 29th in the
Newport Beach City Council Chambers, 3300 Newport Boulevard.
You are invited to cane to the meeting and offer your coa:ents and
suggestions.
Very truly yours,
I �
208 Planning
JAK:rua \
C -2287
See Contract File for Map
Engineering Services Agreement for design of
EA & Interim Control Studies
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PART II - TASK II -F
GENERAL AUDIENCE REPORT
SEDIMENTATION ANALYSIS
NEWPORT BAY WATERSHED
SAN DIEGO CREEK COMPREHENSIVE
STORMWATER SEDIMENTATION CONTROL PLAN
PREPARED FOR THE
CITIES OF IRVINE AND NEWPORT BEACH
AND THE
SOUTHERN CALIFORNIA ASSOCIATION OF GOVERNMENTS
JULY 1982
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TABLE OF CONTENTS
Page No.
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SUMMARY OF DETERMINATIONS . . . . . . . . . . . . . . . . . . . . . . 3
DESCRIPTION OF THE WATERSHED . . . . . . . . . . . . . . . . . . . . . 6
RESULTS OBTAINED FROM PART I1, SEDIMENTATION ANALYSIS . . . . . . . . 9
Task II -A Hydrologic Analysis . . . . . . . . . . . . . . . . . . 9
Task II -B Geomorphic Analysis. . . . . . . . . . . . . . 12
Task II -C Sediment Source Analysis and
and I1 -D Sediment Delivery Analysis . . . . . . . . . . . . . . 16
Task II -E Sediment Transport, Deposition
and Scour in Newport Bay . . . . . . . . . . . . . . . 33
APPLICATION OF SEDIMENTATION ANALYSIS DATA
TO THE DEVELOPMENT OF A COMPREHENSIVE
STORMFLOW SEDIMENTATION CONTROL PLAN . . . . . . . . . . . . . . . . 41
TABLES
1 Peak Flood Flows and Runoff Volumes -
Existing Conditions and Ultimate Conditions. . . . . . . . . . 11
2 Average Annual Sediment Produced from
Upslope Area for Existing Conditions . . . . . . . . . . . . . 21
3 Average Annual Sediment Produced from
Upslope Area for Ultimate Conditions . . . . . . . . . . . . . 22
4 Sediment Inflow and Outflow at Various
Reaches Newport Bay Watershed,
Average Annual (Existing Conditions) . . . . . . . . . . . . . 27
5 Sediment Inflow and Outflow at Various
Reaches, Newport Bay Watershed,
Average Annual (Ultimate Conditions) . . . . . . . . . . . . . 28
6 Sediment Supply to Upper Newport Bay,
Existing Conditions . . . . . . . . . . . . . . . . . . . . . 37
7 Sediment Supply to Upper Newport Bay,
Ultimate Conditions . . . . . . . . . . . . . . . . . . . . . 37
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FIGURES
San Diego Creek Watershed . .
. . .
. . . . . . . . . . . . . .
7
Newport Bay and Vicinity - Middle
Pleistocene . . . . . . . . .
13
Hydrography Mid -19th Century
. . .
. . . . . . . . . . . . . .
14
Present Land Use . . . . . .
. . .
. . . . . . . . . . . . . .
17
Ultimate Land Use . . . . . .
. . .
. . . . . . . . . . . . . .
18
Sediment Production - Terrain
Type
-
Existing Conditions . . . .
. . .
. . . . . . . . . . . . . .
23
Sediment Production - Rates -
Existing Conditions . . . .
. . .
. . . . . . . . . . . . . .
24
Sediment Transport Balance .
. . .
. . . . . . . . . . . .
30
Particle Size Distribution -
Sediment Inflow to Bay . .
. . .
. . . . . . . . . . . . . .
31
Estimated Sediment Inflow to
Upper
Newport Bay -
Storms of Various Return Periods
.
. . . . . . . . . . . . . .
32
Erosion Hazard Map
L:N4 - 0:
The preparation of this report was financed in part through Planning Grant
No. P009325 -01 from the United States Environmental Protection Agency,
under the provisions of section 208 of the Federal Water Pollution Control
Act of 1972, as amended.
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DEFINITION OF TERMS
Antecedent Moisture Condition: The degree of wetness of a watershed at the
beginning of a storm.
Armored Layer: Layer of cobbles and larger -sized particles on stream bottom
reducing susceptibility to channel erosion.
Bed Load: Sediment that moves by saltation (jumping), rolling or sliding
in the bed layer.
Bed Material: The sediment mixture of which the streambed is composed.
Channel Stabilization: Erosion prevention and stabilization of velocity
distribution in a channel by use of impervious linings, drops, revet-
ments, vegetation and other measures.
Contour Line: A line joining points having or representing equal elevations.
Discharge (flow): The rate at which water (or more broadly, total fluids,
plus suspended sediment) passes a given point, expressed in volume per
unit time (e.g., cubic feet per second, or c.f.s.).
Drainage Area: The area that contributes runoff to a stream at a specified
location (concentration point).
Erodible: Susceptible to erosion.
Erosion: Detachment and movement of the solid material from the land surface
by wind, water and ice or by gravity as in landslides. In this report,
erosion is related to movement by water only.
Floodwater Retarding Structure. Dam across a water course usually designed
with an uncontrolled outlet for the temporary storage of runoff.
Gaging Station: A particular site on a stream, canal, lake or reservoir
where systematic observations of gage height or discharge are obtained.
Gully Erosion: Erosion that causes elongated depressions in the land surface
through which water commonly flows only during and immediately after
heavy rains.
Hydrograph: Graphical or tabular representation of flow rate with respect
to time.
Hydrology: Science dealing with the properties, distribution and flow of
water on or in the earth.
Hydrometer Analysis: Determination of particle size distribution of the
finer sediment particles (silt and clay) on the basis of settling
velocities.
>r
MLLW: Mean Lower Low Water datum - This is 2.56 feet below Mean Sea Level
datum.
Particle Size: Diameter in millimeters (mm) of a sediment grain determined by
either sieve or sedimentation methods.
Reach: A comparatively short length of a stream or channel.
Return Period: The average number of years within which a given event will be
equaled or exceeded. A 50 -year frequency flood has a 50 -year return
period, and so on.
Rill Erosion: Erosion causing formation of shallow channels that can be
smoothed out by normal cultivation.
Runoff: The portion of precipitation which is returned to the stream as
surface flow.
Sediment: Solid material that is derived mostly from disintegrated rocks and
is transformed by, suspended in, or deposited from water.
Sediment Load: Amount of sediment carried by running water.
Sedimentation: Deposition of waterborne sediments due to a decrease in velo-
city and a corresponding reduction in the size and amount of sediment
which can be carried.
Sedimentation Basin: Basin or pond at the upper end of a channel or reservoir
to store sediment -laden water for a sufficient length of time for the
sediment to be deposited.
Sheet Erosion: Removal of a fairly uniform layer of soil or material from
the land surface by runoff water.
Sieve Analysis: Determination of particle size distribution of the coarser
sediment particles by passing through sieves of various size openings.
Stream Bank Erosion: Scouring of material and the cutting of channel banks
by running water.
Streambed Erosion: Scouring of material and cutting of channel beds by run-
ning water.
Stream Gradient: The general slope or rate of change in vertical elevation
per unit of horizontal distance of the water surface of a flowing
stream.
Suspended Load: Material moving in suspension in a fluid being kept up by
the upward components of the turbulent currents or by colloidal sus-
pension.
~ Time of Concenttration: Time required for water to flow from the most remote
point of a watershed, in a hydraulic sense, to the outlet.
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Wash Load: That part of the sediment load of a stream which is composed of
particle sizes smaller than those found in the shifting portions of
the streambed.
Watershed: Total land area above a given point on a stream or waterway that
contributes runoff to that point.
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GENERAL AUDIENCE REPORT TASK II -F
INTRODUCTION
Substantial sediment deposition has occurred in Upper Newport Bay in recent
years adversely affecting the Upper Newport Bay State Ecological Reserve.
It is considered urgent that effective actions be taken to reduce the inflow
of sediment to the bay so that the ecological reserve may be effective in
realizing its objectives.
In order to provide a basis for effective actions toward reducing the inflow
of sediment into the bay, the cities of Newport Beach and Irvine have entered
into a cooperative agreement with the Southern California Association of
Governments to study this problem and determine solutions. Funding for this
study is provided in part through a grant from the United States Environmental
Protection Agency.
The cities of Newport Beach and Irvine have entered into an agreement with
Boyle Engineering Corporation to conduct studies to achieve three objectives:
1. To develop an early action and interim sedimentation control plan
for Upper Newport Bay and San Diego Creek and its tributaries which
can be approved for implementation in December 1980 and implemented
in the ensuing months of 1981 prior to the onset of the 1981/82
rainy season.
2. To analyze and characterize the causes, nature and extent of the
sedimentation problems adversely affecting Upper Newport Bay.
3. To develop a comprehensive watershed erosion and stormflow sediment
control plan, with emphasis on a downstream desilting system along
San Diego Creek that can be implemented in the near -term.
The study identified as "The Newport Bay Watershed: San Diego Creek
Comprehensive Stormwater Sedimentation Control Plan" is divided into four
parts:
Part I: Early Action and Interim Control Plan
Part II: Sedimentation Analysis
Part III: Comprehensive Stormflow Sedimentation Control Plan,
Engineering
Part IV: Comprehensive Stormflow Sedimentation Control Plan,
Environmental
Part I: Early Action and Interim Control Plan was completed to the extent
that control measures were recommended for early installation, which include
two in- channel debris basins on San Diego Creek immediately upstream from
MacArthur Boulevard and an excavated basin in Upper Newport Bay immediately
downstream of Jamboree Road. Construction plans and specifications for these
projects have been completed, bids for construction have been received and
project installation will be commenced when the necessary funding has been
accomplished.
-1-
Part II: Sedimentation Analysis, is divided into five tasks for developing
the information required and includes a sixth task to summarize the results
obtained:
Task II -A: Hydrologic Analysis
Task II -B: Geomorphic Analysis
Task II -C: Sediment Source Analvsis
Task II -D: Sediment Delivery Analysis
Task II -E: Sediment Transport, Deposition and Scour in Newport Bay
Task II -F: General Audience Report (Summary of Part II determinations)
These tasks provide information to fulfill the second objective "To analyze
and characterize the causes, nature and extent of the sedimentation problems
adversely affecting Upper Newport Bay."
Task II -A, Hydrologic Analysis. This task provides information on
the runoff characteristics of the watershed: the peak flows and
volumes of flow that occur at various concentration points within the
watershed and at what frequencies of occurrence.
Task II -B, Geomorghico Analysis. This task provides information on
M geologic iii story oT t —ebay and the changes in land use patterns
that may have affected the sedimentation process in the bay.
Task II -C, Sediment Source Analysis. This task provides estimates of
t e sediment yields from various source areas under conditions of
various storm intensities and an average annual estimate.
Task II -D, Sediment Delivery Analysis. This task combines the
informat on eevee epee in tie— Fydr0Togic analysis with that developed
in the sediment source analysis to determine the sediment delivery
process of the watershed and its drainage channels.
Task II -E. Sediment Transport. Deposition and Scour in Newport Bay.
This task provides a description of sediment transport, deposition
and scour characteristics of San Diego Creek discharges through
Newport Bay under various hydrologic and land use conditions within
the watershed.
Task II -F, General Audience Report. This report provides a brief
summary of the results obtained rom the studies included in Part II,
Sedimentation Analysis and indicates how this information will be used
to formulate effective sediment control systems for the watershed
area draining into Upper Newport Bay.
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SUMMARY OF DETERMINATIONS
The objective of this portion of the study was to provide information on
sediment sources and sediment transport characteristics within the San Diego
Creek watershed as a basis for understanding the sedimentation problem in
Upper Newport Bay.
This required a determination of storm runoff characteristics in the water-
shed (hydrologic analysis); consideration of historic and geologic data
affecting present and past sedimentation in Upper Newport Bay (geomorphic
analysis); determination of sediment sources in the watershed and the estima-
ted amounts of sediment produced under existing conditions and that which
will be produced under ultimate conditions of full urban development (sediment
source analysis); estimation of the deposition characteristics of the sediment
entering the stream system (sediment delivery analysis); and an analysis of
the transport of sediment from San Diego Creek storm flows through Upper
Newport Bay (Sediment Transport, Deposition and Scour in Newport Bay).
Some of the significant determinations in these analyses are summarized as
follows:
Runoff volumes and peak flows will be higher under conditions with ultimate
development because of the larger amounts of impervious surfaces. The
increases will be greater for the smaller, more frequently occurring, storms
than for the larger ones occurring less frequently.
The major storm runoff of record occurred in February, 1969. It is estimated
that the peak flow caused by this storm would be equaled or exceeded, on
average over a long period of time, once in 40 years under existing conditions.
Under conditions with ultimate development, peak flows of this size would
occur more frequently because of increased runoff from all storms caused by
development.
Changes in land use over historical times have accelerated the processes of
erosion and sediment transport. The removal of the natural cover in the
watershed for agricultural purposes has increased sheet and rill erosion.
With the provision of drainage ditches, this eroded material is transported
more efficiently through the watershed and deposited in the lower areas.
The estimated average annual sediment production from upslope areas in the
San Diego Creek watershed under existing conditions is 118,300 tons, of which
about two- thirds are silt and clay particles. An additional 38,800 tons are
produced by channel erosion, composed almost entirely of sand particles.
The foothill areas, which include only 28 percent of the watershed, produce
66 percent of the sediment. This is due primarily to the steeper slopes in
these areas.
The total amounts of sediment produced by agricultural areas and open space
are about the same. This is due primarily to open space areas being located
on the steeper slopes. Open space occupies about a third more area than is
used for agriculture.
-3-
Mature urban development produces less sediment than any other land use,
including conditions with natural cover. There is a limited period during
the construction phase of urban development when the land is highly suscep-
tible to erosion.
Construction areas have the highest sediment production rate per square mile
followed in order of production intensity by agriculture, open space and
urban areas.
Estimated sediment production for the watershed under ultimate conditions
is less than for existing conditions. Construction and agriculture, both
high sediment - producing land uses, are assumed to be replaced by mature urban
development in the future.
The estimated rate of sediment production from urban areas is higher under
ultimate conditions than under existing conditions because more urban develop-
ment will occur in the foothill areas.
Sediment delivered to Upper Newport Bay has a much higher percentage of silt
and clay than the sediment produced form the upslope areas. The major part
of the sand particles produced are deposited in stream reaches on the flatter
gradients.
Additional sediment is produced by erosion in channel reaches on the steeper
gradients. This material is composed almost entirely of sand particles which
tend to be redeposited in stream reaches on the flatter gradients.
Under conditions of ultimate development channel erosion will increase greatly
unless channel stabilization measures are installed as the development occurs.
This will be caused by increased runoff from the developed areas and the
reduced amounts of sediment produced by the upslope areas. Storm flows tend
to transport their full capacity for sand particles if they are available.
Unstable channels provide these particles by erosion.
Under existing conditions less sediment is delivered to Upper Newport Bay
than is generated from upslope areas. Under conditions of ultimate develop-
ment without channel stabilization measures more sediment will be delivered
to Upper Newport Bay than is produced from upslope areas.
Under existing conditions the estimated average annual amount of sediment
entering Upper Newport Bay is 85,500 tons (53 acre -feet) of which about 82
percent are silt and clay particles and 18 percent sand particles.
Under ultimate conditions of development the estimated average annual amount
of sediment that will enter Upper Newport Bay is 64,500 tons (40 acre -feet)
of which about 62 percent are silt and clay particles and 38 percent sand
particles. Appropriate channel stabilization measures would greatly reduce
the sand particles delivered to the bay.
It is estimated that between 80 and 90 percent of the sediment delivered to
Upper Newport Bay is deposited north of "The Narrows." The sand particles
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and coarse silt are retained in the northern end of Upper Bay. Clay and fine
silt particles deposit in the basin north of "The Narrows" with additional
portions being deposited in other parts of the bay, a relatively small portion
is carried to the ocean.
If the present situation continues the upper basin will continue to fill with
mud and sand and its effectivenes in trapping fine sediment will diminish; and
will eventually become a mud flat with elevated marshes.
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DESCRIPTION OF THE WATERSHED
The San Diego Creek watershed, from which the runoff discharges into Upper
Newport Bay, has a drainage area of about 118 square miles (75,500 acres).
The total drainage area into Newport Bay is about 154 square miles (98,500
acres). This includes the Santa Ana -Delhi Channel and other areas which drain
directly into the bay. There are three different geographical areas within the
watershed: the rugged foothills, the flat alluvial Tustin Plain, and the
Coastal Plain (Figure 1).
The foothill areas have slopes ranging from 15 to 75 percent and an average
annual rainfall of about 17 inches. The predominant land uses are for cattle
grazing and wildlife areas. They include the major erosion hazard areas in
the watershed because of the steep slopes, higher rainfall intensities, and
soil and cover characteristics (see Exhibit 1). Severe sheet erosion occurs
in areas having limited cover protection and erosive actions occur in unstable
channel sections.
The alluvial plain has slopes ranging from 0 to 15 percent and average annual
rainfall of about 13 inches. The predominant land use is for high -value
agricultural production including citrus fruits, avocados, truck crops, grain,
and nurseries. The soils in this area are generally very erosive, but because
of the flatter slopes and managed land use, erosion is controlled except for
the high intensity storms. The eroded material from these areas is composed
predominantly of the finer particles which are difficult to trap and tend to
continue through the watershed to Upper Newport Bay.
The Coastal Plain also has the flatter slopes and average annual precipitation
of about 13 inches. This area is largely urbanized with minimal erosion.
San Diego Creek has two major tributaries of about equal size. Peters Canyon
Wash includes Peters Canyon, Rattlesnake Canyon and Hicks Canyon Washes which
have their headwaters in the foothills of the Santa Ana Mountains. Elevations
range from about 40 feet at its junction with San Diego Creek to a peak above
Hicks Canyon with an elevation of 1775 feet. Stream gradients range from 320
feet per mile in Hicks Canyon to less than 10 feet per mile along Peters
Canyon Wash near its junction with San Diego Creek. The valley is a flat
alluvial plain with an average slope of 2 percent. The existing channels are
well defined and have been improved somewhat for agricultural drainage.
These channels have been located for the convenience of agriculture and do
not always follow the natural drainage pattern of the land. As a result,
when the channels reach their capacities, excess flows will break away from
the channels and sheet flow across the alluvial plain. The total drainage
area of Peters Canyon Wash above its junction with San Diego Creek is about
44 square miles.
Above its junction with Peters Canyon Wash, San Diego Creek extends in an
easterly direction to include Bee Canyon, Round Canyon, Agua Chinon Wash,
Borrego Canyon Wash and Serrano Creek, all of which have their headwaters in
the foothills of the Santa Ana Mountains. The streams from these headwater
areas flow southwestward across an alluvial plain into San Diego Creek.
Elevations range from about 40 feet at its junction with Peters Canyon Wash
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to a peak above Round Canyon with an elevation of 1770 feet. Stream gradients
range from 140 feet per mile in Bee Canyon to about 30 feet per mile immediately
above its junction with Peters Canyon Wash. The valley, including the U.S.
Marine Air Base, is an alluvial plain with an average slope of 2 percent.
The existing channels are well defined and have been improved somewhat for
agricultural drainage. As on Peters Canyon Wash, they have been located for
the convenience of agriculture and do not always follow the natural drainage
pattern of the land. When these channels reach their capacities, excess
flows will overtop the channels and sheet flow across the alluvial plain.
The total drainage area of San Diego Creek above its junction with Peters
Canyon Wash is about 46 square miles.
The channel gradient on San Diego Creek downstream from the San Diego Freeway
is quite flat (S= 0.0009 foot /foot, approximately).
The San Diego Creek watershed is rapidly changing from agricultural use to
urban development. The major areas of urban development are on the westerly
portion of the watershed, primarily in the Peters Canyon Wash drainage area.
It is anticipated that within the next 30 to 40 years the lands will be
entirely in urban uses except for the rugged foothill areas.
The Santa Ana -Delhi Channel drains an area of about 18 square miles adjacent
to the western edge of the San Diego Creek watershed. This channel discharges
directly into Upper Newport Bay. The area is almost totally urbanized.
Other small drainage areas discharge directly into Newport Bay.
so
RESULTS OBTAINED FROM PART II, SEDIMENTATION ANALYSIS
Technical Memoranda been have completed for:
Task II -A - Hydrologic Analysis
Task II -B - Geomorphic Analysis
Tasks II -C - Sediment Source Analysis
and II -D Sediment Delivery Analysis
Task II -E - Sediment Transport, Deposition and Scour in Newport Bay
Following are synopses of these technical memoranda indicating their content
and some of the significant determinations. More detailed information may be
obtained by reference to the technical memoranda.
Task II -A - Hydrologic Analysis
The technical memorandum for Part II, Task II -A: Hydrologic Analysis, provides
information on the parameters and procedures used in making the hydrologic
analysis, and summarizes the results obtained. This information was used in
the sediment delivery analysis (Task II -D) and will be used for the development
and analysis of alternatives for inclusion in the Comprehensive Stormflow
Sedimentation Control Plan (Part III). It is not intended for use beyond
these purposes.
This hydrologic analysis provides runoff hydrographs for 24 -hour duration
(general) storms using parameters outlined in the Orange County Flood Control
District Hydrology Manual. These synthetic hydrographs were computed using
the SCS Computer Program for Project Formulation- Hydrology (TR -20). They
were computed for storms having 2 -, 5 -, 10 -, 25 -, 50 -, and 100 -year return
periods. These hydrographs are basic information for use in Task II -D, Sediment
Delivery Analysis.
Runoff hydrographs for 3 -hour duration (local) storms were also determined
for 25 -, 50 -, and 100 -year return periods. The parameters used are in
accordance with those specified in the Orange County Flood Control District
Hydrology Manual and the synthetic hydrographs were computed using the SCS
Computer Program for Project Formulation - Hydrology (TR -20). These hydrographs
provide capacity requirements for channels and conduits when floodwater
retarding reservoirs are not a part of the flood control plan within drainage
areas of such sizes that are covered by these high intensity, short duration
storms.
For the evaluation of floodwater retarding reservoirs, hydrographs for the
100 -year return period 24 -hour duration (general) storms and the 3 -hour
duration (local) storms are used to determine the potential for peak flow
reduction within the limitations of a specific reservoir site. Generally,
the hydrographs for the 24 -hour duration (general) storms are critical in the
evaluation of floodwater retarding reservoirs because the flood volumes are
much larger than for the 3 -hour duration (local) storms. The peak flows for
the 3 -hour duration (local) storms are much higher than those of the 24 -hour
duration (general) storms and are susceptible to greater peak flow reduction
because of their smaller volumes.
The study area includes the entire drainage area of San Diego Creek. The
hydrologic analysis also includes the additional drainage areas of the Santa
Ana Delhi Channel and other small drainage areas into Upper Newport Bay as
these flood flows are also a factor in considering sediment movement in
Upper Newport Bay.
The total drainage area was divided into 84 subdrainage areas to provide hydro-
logic information for all watershed segments as required for other parts of
this study.
These hydrologic analyses were made for existing conditions and for conditions
with ultimate development.
The results obtained indicate good correlation with a statistical analysis of
the 29 years of runoff records at a gaging station on San Diego Creek near
Irvine (D.A. 40.5 sq. mi.) operated by the United States Geological Survey.
They also compare favorably with peak flood flows estimated by the Corps of
Engineers for their Intermediate Regional Flood (100 -year return period) used
in their flood plain information reports for San Diego Creek and Peters Canyon
Wash.
The runoff volumes and peak flows estimated for existing conditions and for
conditions of ultimate development indicate that both higher volumes and peak
flows will occur as continued development occurs. This is due to the increased
areas of impervious surfaces caused by urban development and the decreased
times of concentration for runoff to reach concentration points within the
watershed due to channel improvements with higher velocities of flow. These
increases are greater for the more frequently occurring storms than for the
less frequent ones as is shown on Table 1. This is because of the higher
antecedent moisture conditions that exist when the high intensity portion of
the storm pattern occurs with a less frequently occurring storm.
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Task II -B Geomorphic Analysis
The technical memorandum for the Geomorphic Analysis titled "Geomorphology of
the San Diego Creek - Newport Bay Area" was prepared by Stanley W. Trimble,
Department of Geography, University of California, Los Angeles.
This memorandum describes the physiography, geology and soils characteristics
of the study area. It also describes the geologic and cultural changes that
have occurred which have affected the drainage pattern of the watershed into
Upper Newport Say; and the production and transport of sediment within the
watershed.
Over geologic time the Santa Ana River has meandered across the Los Angeles
alluvial plain and in middle Pleistocene times the river had cut a channel
around the north end of Newport Mesa and out through the current Newport Bay
trough (Figure 2). Sea level was considerably lower at that time. A rise in
the sea level followed with the sea extending 7 -10 miles inland. Newport
Mesa initially remained as a low island but was later inundated. As the area
emerged from the sea near the end of the Pleistocene epoch, the Santa Ana
returned to the Newport Bay trough and scoured at least part of the marine
sediments accumulated during the inundation.
During the following few thou -and years the river may have intermittently
reentered the bay because a series of marine and estuarine deposits filled
the trough floor. This may explain the presence of fine silts and clays at
greater depths in the upper end of the bay.
An alternative hypothesis is that the Santa Ana shifted to somewhere near its
present location, formed a barrier island blocking the bay similar to the
present Balboa Peninsula, allowing sediment from local erosion to be deposited
in an estuarine environment, as was the case from about 1860 to quite recently.
Such a low- energy environment and the presence of salt water to promote
flocculation would probably require such a period of time for sediment to
accumulate.
These and other hypotheses related to the Santa Ana River and geologic changes
are factors to be considered in understanding the profiles of sediment
deposited in Newport Bay.
San Diego Creek did not have integrated drainage nor regular drainage to the
sea at the time of the European settlement. Sediment -laden streams flowed
through the steep valleys to the Tustin Plain where the slope suddenly
decreased. The resulting decrease in velocities and the lateral spreading of
the flows caused rapid infiltration and the deposition of coarser sediment,
creating alluvial fans at the base of the hills. The deposited coarse
sediments allowed rapid infiltration and it is doubtful that most flows
continued across the Tustin Plain to the southeast. It appears that the only
channel extending across much of the Tustin Plain was the San Diego Creek
proper, but few of its tributaries were included (Figure 3).
Even when streamflow did travel across the Tustin Plain, it rarely flowed
into the sea. Drainage into Upper Newport Bay was apparently blocked by a
-12-
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narrow ridge at the head of the trough. Exceptional storm flow from the San
Diego Creek basin was ponded in an ephemeral lake located between Upper
Newport Bay and the present site of Santa Ana (Figure 3). The ephemeral lake
bed and the area north and east was usually swampy and marshy and was known
as the "Swamp of the Frogs."
These wet areas, as well as the remainder of the Tustin Plain, were later
drained by ditches. These ditches were expanded to integrate the drainage of
San Diego Creek and all was artificially channeled into Upper Newport Bay.
Two important and related geomorphic problems emerge. 1) The pre- settlement
Tustin Plain was adjusted to non - channeled influent streams with a base level
of over 30 feet above sea level. A new base level of sea level was imposed
and the streams were artifically channeled so that important erosional
adjustments had to take place so long as the stream channels were erodible.
This process continues at present and will continue until an equilibrium
slope has been attained. 2) A sediment sink, the Tustin Plain, has been
converted into a sediment source.
Changes in land use over historical times have accelerated the processes of
erosion and sediment transport. The lands in the study area were parts of
three Spanish ranches and used primarily for cattle grazing. More extensive
commercial agriculture became important after 1900 and extensive drainage and
irrigation development began.
Land use in the watershed has become progressively more intensive in the
years since 1930. This more intensive use relates to agricultural use as
well as urban use.
When the natural cover in the watershed is removed for agricultural purposes,
especially for clean - cultivated crops, the land becomes more susceptible to
sheet and rill erosion. With the provision of drainage ditches, both local
and trunk, this eroded material is more efficiently transported through the
watershed and sedimentation tends to occur in the lower reaches of the
watershed rather than locally.
When urban development occurs there is a limited period during the construc-
tion phase when the land is highly susceptible to erosion. However, when
these urban developments mature with paved surfaces, landscaping and stabi-
lized channels, sediment production is greatly reduced as compared with
natural conditions.
-15-
Tasks II -C and II -D Sediment Source Analysis and Sediment
Delivery Analysis
The objective of the sediment source analysis was to estimate the sediment
production rates from the major sediment source areas (foothills, unstable
channels, agricultural areas, urban areas and construction sites) in the
watershed for the existing (1979 -80), and ultimate land use for the 2 -, 5 -,
10 -, 25 -, 50- and 100 -year recurrence interval stormflows for the 24 -hour
duration storm.
In general, most of the foothill areas owned by The Irvine Company are held
in agricultural preserve and are used for wildlife habitat and cattle grazing.
According to The Irvine Company's 5 -year Development Plan, the steeper areas
will probably remain in agricultural preserve, while certain portions will be
withdrawn in 1983 for development.
The predominant land use in the Tustin Plain is high -value agricultural
production, including citrus fruits, avocados, truck crops, grain and
nurseries. Much of this area is scheduled for urban development within the
next ten years. It is estimated that within 50 years the entire area suitable
for such development will be urbanized.
The western portion of the watershed on the Coastal Plain has been largely
urbanized except for certain areas near Newport Bay. Ultimately, most of
these areas will be developed at least for rural residential use.
At present (1979 -80 data) approximately 23 percent of the watershed is in
agricultural uses, 47 percent is urbanized, 28 percent is open space and two
percent is in areas where construction is in progress (Figure 4).
Under anticipated ultimate conditions, urbanized areas will comprise 81
percent of the watershed, 8 percent will be rural, and 11 percent will remain
open space. No land was assumed to be used for agriculture (Figure 5).
However, the City of Irvine General Plan indicates an area of about 4,000
acres in permanent agriculture.
A more detailed identification of land use in the watershed was made in order
to determine sediment yield from each subbasin. Each of the 84 hydrologic
subbasins defined in the Technical Memorandum for Hydrologic analysis (Phase
II, Task II -A) was identified as having either predominantly foothill or
valley characteristics. The subbasins were subdivided into five land use
categories: agriculture, open space, urban, rural and construction. This
was done for two separate time frames: present (1979 -80) and ultimate
development.
Sediment yield from a watershed is the result of the interaction of two con-
siderations. The first consideration is the supply of sediment originating
from upslope areas which enters the stream system. This includes sediment
contributed by sheet and rill erosion, gully erosion and landslides. The
second consideration is the transport of sediment through the stream system.
The fine sediment eroded from upslope areas is usually carried away by the
stream without much deposition. In contrast, the transport of coarser sediment
is dependent on the transport capacity of flows in the channels.
arm
W
Estimation of
version of the
to predict the sediment generated by sheet and rill erosion. It does not
estimate other types of sediment production, such as gully erosion. However,
gully erosion is recognized as a minor source of sediment as compared to sheet
and rill erosion in the study area. On this basis, it was not considered in
the sediment source analysis.
the sediment eroded from upslope areas was based on a modified
Universal Soil Loss Equation (USLE). The USLE was developed
The USLE provides estimates of average annual erosion rates. It does not
provide estimates of sediment delivered to a stream. Eroded soil materials
often move only short distances before decreased velocities cause their
deposition. They may remain in the fields where they originated or may be
deposited on less steep slopes that are remote from the stream system.
A modified version of the USLE was used in this study which uses a runoff
factor as the rainfall energy factor in the USLE. This modification enables
prediction of sediment yield resulting from individual storms as well as a
long -term average annual value. It also provides estimates of sediment yield
delivered to the stream system.
Estimates of gross sediment yield to the stream system from upslope areas
were obtained with the application of the modified version of the USLE.
Determination of transport characteristics in the stream system requires
information on particle size distribution. Representative particle size
distributions for upslope areas and major channel reaches were obtained by
combining information available from previous studies with field sampling and
sieve and hydrometer analyses. This information will also be valuable for
sediment control planning. Estimates of particle size distribution in flood
flows were based on transport capacities of the flows for each fraction size.
A computer program was developed incorporating the analysis procedures
described in the technical memorandum. This program was used to estimate
upslope area sediment production for each land use in each of the 84 subbasins
The sediment produced by storms with recurrence intervals of 2, 5, 10, 25,
50, and 100 years under present (1979 -80) and ultimate development conditions
was estimated. In addition, the particle size distribution of total sediment
produced in each basin during each of these storms was determined. Particle
size ranges selected for consideration are shown below.
PARTICLE SIZE RANGES
Sediment Material Grain Diameter (mm) Mean Diameter (mm)
Clay 0 - .004 .0015
Silt .004 - .0625 .024
Fine Sand .0625 - .25 .120
Coarse Sand >.25 .5
-19-
The computer print -out includes estimates of sediment produced by storms of
the specified return periods and the average annual for each of the subbasins
in the watershed. The amounts of sediment produced by various land use
categories within each subbasin are also tabulated: agricultural, open space,
urban and construction. Particle size fractions of the total sediment produced
from each of the subbasins is also shown. Separate analyses and print -outs
were made for the total watershed for existing conditions and for conditions
with ultimate development.
The results obtained were verified by the limited sedimentation data available
for the Upper Newport Bay watershed. This included correlation with the
amounts of sediment that have accumulated in the Sand Canyon reservoir over
the past 38 years and the wash load (clay and silt) indicated by the sediment
data obtained at three USGS gaging stations in the watershed.
All available methods for computing sediment yield, including the methods used
in this study, can be expected to give only estimates. Error in the estimates
could be in the range of 0.5 to 2.0 or more when they are not verified with
field data such as stream or reservoir sediment data. Estimates of sediment
yield from individual subbasins could have a fairly large error. This also
applies to particle size distributions of sediment produced for each land use,
because soil samples used in the analyses may not represent each subbasin
accurately. However, the range of error will be reduced when larger areas
of the watershed are considered.
Results obtained for groups of basins which drain into the three USGS gaging
stations compared well with USGS data. Consequently, the estimates for the
entire watershed are considered to be within a reasonable level of accuracy.
Average annual sediment production in foothill and valley areas of the water-
shed is summarized in Tables 2 (existing conditions), and 3 (ultimate condi-
tions. Sediment production for each land use within these areas is listed
along with totals for the two areas. Figure 6 illustrates the sediment
production- terrain type relationship in the watershed under existing condi-
tions. Figure 7 illustrates the sediment production rates for the various
land uses.
The following conclusions are evident from these results:
1. Significantly greater quantities of sediment are produced in foothill
areas. This is largely due to the relatively steep slopes in these areas.
2. Construction areas have the highest sediment production rate, followed by
agricultural, open space, and urban areas.
3. Total sediment production under existing conditions appears to indicate
that open space and agricultural areas have similar sediment production
rates. However, this is only because more of the open space areas are
in the steeper foothills.
4. The average rate of sediment production from urban areas is higher under
ultimate conditions. This is because in the future more urban development
will occur in the foothills.
-20-
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SNOT 0001
IGURE.
7
5. Total sediment production for the basin as a whole is less under
ultimate conditions. This is because construction and agriculture,
both high sediment - producing land uses, were assumed to be eliminated
under ultimate conditions.
The total sediment load in a stream is the sum of bed material load and wash
load. The bed material load is that part of the total sediment discharge
which is composed of grain sizes found in the bed. The wash load is that
part composed of particle sizes finer than those found in appreciable quanti-
ties in the bed. In this study, wash load was estimated to contain particle
sizes less than 0.0625 mm (silt and clay).
Wash load can be transported easily in large quantities by the stream, and
availability usually limits the quantity of fines in a stream rather than
transport capacity. Fine material transported as wash load can originate in
upslope areas and stream banks. Although some stream bank sloughing has been
noted in certain Upper Newport Bay watershed stream reaches, particularly
during high flows, wash load contributed by bank erosion was assumed to
be negligible. This is a reasonable assumption because stream bank erosion
is minor compared to other types of erosion. In addition, most stream banks
in the study area contain a large percentage (roughly 60 to 80 percent) of
coarse materials which would become bed material load. Therefore, the wash
load passing a given cross section of a stream was assumed to be approxi-
mately equal to the quantity of fine sediment (silt and clay sizes) generated
from the upslope areas.
An exception to the above is San Diego Creek below Campus Drive. In this
reach, the wash load (mainly silt sizes) starts to settle as the velocity
decreases. As a result, the bed material in this area contains appreciable
quantities of silt size fractions, approximately 10 to 30 percent.
Most of the streams in the Upper Newport Bay watershed are characterized by
sandy streambeds with no armoring layer. Also, no cohesive material is
present in the channels to inhibit the detachment of particles into the
flow. Under this condition, no matter how much sediment is produced from
upslope areas or upstream reaches, the bed material load passing a given
reach is determined by the transport capacity of the reach. If the supply
of coarse sediment from upslope areas or upstream reaches is less than the
sediment transport capacity, erosion will occur to satisfy the transport
capacity. On the other hand, excess sediment supplied by upstream areas
will deposit in the reach. Thus, the bed material load will eventually
equal the sediment transport capacity of the reach. In this case, the bed
material load can be estimated by applying an appropriate sediment transport
capacity function.
The total bed material load for various streams under consideration was
simulated using a computer program developed by Boyle Engineering Corpora-
tion.
Sediment transport characteristics of major stream reaches were determined
according to the analysis procedures described. A computer program was
developed to calculate the sediment transport of a given reach for specified
particle sizes.
-25-
Detailed results of the sediment delivery analysis are presented in Appendix
B of the Technical Memorandum for the Sediment Source Analysis and Sediment
Delivery Analysis (Part II - Tasks II -C and II -D).
Tables 4 and 5 illustrate the sediment transport characteristics of San Diego
Creek under existing and ultimate conditions. Under existing conditions (Table
4) it is indicated that the sediment inflow to the stream system is augmented
by additional sediment (27,400 tons) by channel erosion in the reach upstream
from Sand Canyon Avenue. In the reach between Sand Canyon Avenue and the
junction with Peters Canyon Wash it is indicated that the sediment inflow
exceeds the sediment outflow by 45,100 tons (deposition). This is the Wood-
bridge Channel reach with grade stabilization structures which require conti-
nuing maintenance to remove deposited materials. These characteristics of
deposition and erosion are indicated for other reaches of San Diego Creek
and Peters Canyon Wash in this table.
Similarly, Table 5 indicates the deposition and erosion that is anticipated
to occur under ultimate conditions. Under conditions of ultimate development,
the streamflows will be larger, particularly for the more frequently occurring
storms. Sheet and rill erosion will be greatly reduced and the streamflows
will have increased capacities for additional coarse sediment than under
existing conditions because of the reduced inputs and the higher velocities
and volumes of runoff. Consequently, more channel erosion will occur than
under existing conditions.
The coarser particles of this channel- eroded material along with the other
coarse sediment particles will tend to be deposited in channel reaches with
flat gradients. However, it is estimated that more coarse sediment particles
will be discharged into Upper Newport Bay under ultimate conditions than
under existing conditions.
The total average annual sediment generated from upslope areas and that
delivered to Upper Newport Bay are summarized below. The values in the
tables are in 1000 tons.
*From the total drainage area of 137.1 sq. mi. excluding drainage areas
above the major reservoirs: Peters Canyon, Rattlesnake, Siphon, Laguna,
and Sand Canyon reservoirs.
-26-
Existing
Ultimate
Silt &
Coarser
Silt &
Coarser
Clay
Sediment Total
Clay
Sediment Total
Sediment generated
78.5
36.4 114.9
39.6
17.3 56.9
from upslope areas*
Sediment delivered
70.3
15.2 85.5
39.6
32.9 64.5
to Upper Newport Bay
*From the total drainage area of 137.1 sq. mi. excluding drainage areas
above the major reservoirs: Peters Canyon, Rattlesnake, Siphon, Laguna,
and Sand Canyon reservoirs.
-26-
TABLE 4
SEDIMENT INFLOW AND OUTFLOW AT VARIOUS REACHES
NEWPORT BAY WATERSHED
ANNUAL AVERAGE
(EXISTING CONDITIONS)
TOTAL SEDIMENT DELIVERED 85.5
TO UPPER NEWPORT BAY
-27-
43 39 17 1
seaiment
Yarticie
size
Distribution li)
Inflow
and Outflow
Fine
Coarse
Location
(1,000 Tons)
Clay
Silt
Sand
Sand
San Diego Creek above
Sand Canyon Avenue
Inflow
60.8
28
36
26
11
Outflow
88.2
19
25
42
14
San Diego Creek between
conf. with Peters Cyn.
Wash and Sand Cyn. Ave.
Inflow
91.3
20
25
41
14
Outflow
46.2
40
49
10
1
Peters Cyn. Wash above the
conf. with E1 Modena
Irvine Channel
Inflow
18.5
38
39
18
5
Outflow
26.8
26
27
30
17
E1 Modena Irvine Channel
Inflow
5.8
27
39
18
5
Outflow
6.5
24
34
33
8
Peters Canyon between the
conf, of San Diego Creek
and El Modena Irvine Channel
Inflow
36.3
27
30
29
14
Outflow
38.7
27
28
39
7
San Diego Creek between
Campus Dr. and the conf.
with Peters Canyon Wash
Inflow
91.5
34
39
23
4
Outflow
86.7
35
41
21
2
San Diego Creek between
Jamboree Rd. and Campus Dr.
Inflow
100.9
35
40
22
3
Outflow
79.2
45
41
14
0
TOTAL SEDIMENT DELIVERED 85.5
TO UPPER NEWPORT BAY
-27-
43 39 17 1
TABLE 5
SEDIMENT INFLOW AND OUTFLOW AT VARIOUS
NEWPORT BAY WATERSHED
ANNUAL AVERAGE
(ULTIMATE CONDITIONS)
REACHES
Sediment
Particle
Size
Distribution
Inflow
and Outflow
Fine
Coarse
• Location
(1,000 Tons)
Clay
Silt
Sand
Sand
San Diego Creek above
Sand Canyon Avenue
Inflow
36.4
30
36
17
16
Outflow
98.3
11
13
56
19
San Diego Creek between
conf. with Peters Cyn.
Wash and Sand Cyn. Ave.
Inflow
98.5
11
14
56
19
Outflow
32.1
35
41
21
2
Peters Cyn. Wash above the
conf. with El Modena
Irvine Channel
Inflow
7.8
37
36
16
11
Outflow
25.6
11
11
57
21
E1 Modena Irvine Channel
Inflow
1.2
48
52
0
0
Outflow
5.7
10
11
65
15
Peters Canyon between the
conf, of San Diego Creek
and El Modena Irvine Channel
Inflow
31.8
12
11
58
19
Outflow
38.3
10
9
68
13
San Diego Creek between
Campus Dr. and the conf.
with Peters Canyon Wash
Inflow
72.7
21
24
46
9
Outflow
65.1
24
27
46
3
San Diego Creek between
Jamboree Rd. and Campus Dr.
Inflow
71.5
25
28
44
3
Outflow
56.8
32
35
32
1
TOTAL SEDIMENT DELIVERED 64.5
TO UPPER NEWPORT BAY
50
30 32 36 2
h
1
R\
;y
As can be seen from the above table, under existing conditions 6ch of the
sediment generated from upslope areas will be deposited in the stream before
entering the bay. On the other hand, the sediment delivered to the bay
under ultimate conditions is greater than that generated from the upslope
areas. This is because urbanization causes increased runoff rates, and con-
sequently a higher sediment transport capacity in the receiving stream. Chan-
nel scour results, increasing the quantity of sediment delivered downstream
(see Figure 8). Most of this scoured material would be deposited in channel
reaches on flatter gradients. However, some increase in sand particles
delivered to Upper Newport Bay would occur. The probable installation of
channel stabilization measures concurrent with urban development as necessary
flood control measures will reverse this tendency.
Figure 9 indicates the particle size distribution estimated for sediment
entering Newport Bay under existing conditions and for ultimate conditions.
The higher percentage of sand particles estimated for ultimate conditions
reflects the reduced amounts of the finer particles produced by surface and
rill erosion and the increased channel erosion caused by increased flows
with greater capacities for transporting sand particles.
The sediment inflow to Newport Bay varies greatly with the amounts of runoff
produced by storms in the watershed. Figure 10 compares the amounts of
sediment inflow to Upper Newport Bay caused by storms of various return
periods as a percentage of the estimated average annual sediment inflow.
The sediment transport analysis for ultimate conditions was made under the
assumption that channel geometry and streambed materials are the same as
those prevailing under existing conditions. However, when the sediment
supply from upslope areas is limited, the streams will tend to reach equili-
brilm through slope adjustment or development of an armored layer, which was
not considered in this study. Ultimately, the sediment delivered to the bay
will be approximately equal to that generated from upslope areas on a long
term average basis. Thus, the results presented in this report for ultimate
conditions should be viewed as conservative and temporary only until the
equilibrium stage is reached. In addition, channel improvement during urban
development will further reduce sediment delivery rates.
_29_
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Task II -E Sediment Transport, Deposition and
Scour in Newport Bay
The technical memorandum for this task was prepared by Ray B. Krone and Asso-
ciates and Boyle Engineering Corporation.
Estuaries are regions of hydrologic transition from the varying fresh water dis-
charges of influent streams to the tidal, saline oceans. The water movements
sediment distribution processes, and biology throughout estuarial regions are
influenced by both the stream discharges and the ocean tides and salinity.
Upper Newport Bay hydrology is characteristic of such estuaries in areas having
seasonal rainfall. This already complex hydrology is complicated
further by daily on -shore and off -shore breezes and by seasonal, strong Santa
Ana winds that generate waves in the region north of The Narrows. A descrip-
tion of the transport of sediments discharged by San Diego Creek into the
hydrologic environment of Upper Newport Bay is presented in this technical
memorandum.
Sediments are transported by water movements. Even a qualitative description
of sediment transport in Upper Newport Bay requires first a description of
water circulation. Fine and coarse sediment particles are transported
differently, and their modes of transport are described. These descriptions
are then synthesized to present a description of sediment transport in Upper
Bay. Finally, a description of changes in Upper Bay is presented that can be
expected if the present regime is allowed to continue.
These descriptions are based on review of data available from studies of Newport
Bay and on information available from sediment transport in other estuaries.
Water Circulation
Tidal Currents
The ocean tides at the entrance to Newport Bay are diurnal tides with a 24.8 -
hour period. The diurnal high and low tides result from the phase relation
of the sun and moon, so that the relative ranges of the two daily tides
continuously vary from small to large over a 28 -day period. The actual
elevation reached by a particular tide is further influenced by wind set -up
on the ocean and in Upper Bay by the magnitude of fresh water discharge.
The rise and fall of the ocean, combined with the succession of constrictions
and basins that characterize Lower and Upper Bays, cause reversing tidal
currents with the Bays. The large volume of the basins filled and emptied by
the tides, their tidal prisms, cause tidal currents to be strongest in the
connecting channels.
Stream Flows
The discharges from San Diego Creek are ephemeral, and the magnitude of flows
varies over a wide range. The ten -year storm flow, for example, is over
10,000 cfs under present conditions and is estimated to be over 13,000 cfs
under ultimate conditions of development. Even a two -year storm will cause
discharges of over 2,000 and 5,000 cfs for present and ultimate watershed
conditions, respectively. These large fresh water discharges will alter Upper
Bay tidal movements and will raise the water surface elevations in the norther
Upper Bay.
-33-
Gravity Circulations '
Field studies have shown that vertical salinity gradients are found in waters
along the length of Upper Bay. Such gradients result from gravity circula-
tions. Seawater is more dense than freshwater. Since there is little time -
averaged head difference between Bay and ocean waters due to the open Bay
entrance, the difference in density causes the more dense ocean water to
intrude upstream along the bed under the fresher, less dense surface waters.
This density- driven intrusion, combined with vertical mixing due to channel
friction and the back and forth water movement caused by tides, results in a
net landward movement of near -bed waters, and upward mixing of these waters.
The near - surface seaward flow of fresher water is thus augmented by the
intruding ocean water. The combined seaward flowing, upper discharge at the
seaward end of the mixing zone can be as much as ten times the freshwater
flow into the estuary.
Waves
Waves in the shallow region north of The Narrows due to on -shore breezes are
estimated to range up to six inches. Spring and fall Santa Ana winds, however,
blow down the estuary and generate waves up to two feet high at high tide
when the fetch is long. Lesser waves would be expected at lower tides, but
the strength and direction of these winds indicate that wave heights would be
greater than those generated by on -shore breezes.
Sediment Transport Processes
Sand and coarse silt grains are transported as discrete particles. The trans-
port of fine sands in streams is usually largely in suspension. Sand and
coarse silt particles have appreciable settling velocities, however, and the
amount transported varies sensitively with the stream flow: when the flow is
reduced, particles spend a greater portion of the time in the bed and less
time in suspension. When material is available in the bed the sand and coarse
silt load can increase quickly with an increase in discharge. Bed material
is continually supplied to the San Diego Creek drainage by soil erosion in the
watershed in amounts that depend on local soils, exposure, and precipitation.
Clay and fine silt particles are also transported in either discrete particles
or small aggregates in the freshwaters of the San Diego Creek drainage system.
Their small sizes result in very low settling velocities, with the result
that they rarely settle to the bed, even at low discharges. These particles
are referred to as "wash load." The amount of such material transported in
suspension in any section of a stream channel is unrelated to the local flow.
The wash load is determined entirely by the amount of soil erosion in the
watershed and erosion of stream banks.
The settling velocity is the critical parameter determining transport and
deposition of suspended particles. The settling velocities of clay and fine
silt particles vary depending on their environment, however. As mentioned
above, fine wash load particles tend to remain suspended in rainwater.
-34-
When stream waters mix with ocean waters to the extent of one or two parts or
more ocean water to 32 parts streamwater, the particles become cohesive. Even
though the particles are mutually repulsive in fresh runoff waters, they become
cohesive as the waters enter an estuary.
Aggregates of estuarial sediments include silt particles. When organic mate-
rial is available, such as algae or detritus, that material is also included
in aggregates.
When aggregates suspended in quiescent or slowly flowing waters settle to the
bed, they stick. A "rain" of particles accumulate on the bed, and as the
accumulation grows thicker, the weight of the deposit crushes the lower
aggregates in the bed, making the bed more dense and stronger. A bed surface
is just an aggregation of deposited aggregates, but below the surface a few
centimeters the strength of the bed increases. Erosion of a cohesive bed by
slightly increased currents or by moderate wave action may erode just the
weak surface or, if the wave or current stress on the bed in stronger, it
may erode deeper. It is important to recognize, however, that a cohesive
sediment deposit is stronger with depth below its surface.
The contrasts between the processes of non - cohesive sand and coarse silt
transport and those of the finer cohesive particles is apparent. Sand
transport, of discreet grains having high settling velocity, tends to maintain
equilibrium with the bed, depending on the flow or wave action, and sand
deposits do not normally become significantly more resistant to erosion with
consolidation. Fine cohesive particles, on the other hand, may have changing
settling velocities, depending on dissolved salt concentrations and hydraulic
conditions, and the strength of a cohesive sediment bed increases with depth,
at least to a foot or more.
Marsh Development
Marsh lands are a dominant feature of the southern portion of Upper Newport
Bay, and marshes appear to be developing along the perimeter of the northern
portion. Additional marshes will possibly develop there in the future. This
outline of the processes that lead to the development of marshes is presented
to aid in the description of future changes of Upper Newport Bay.
S artina grows when the duration of inundation by tides is within its tolerance
or su mergence. In Newport Bay the duration of inundation becomes suitable
at the elevation of 2.0 ft. MLLW, and Spartina successfully competes with
other marsh plants up to 3.2 ft. MLLW. par_ina requires also a substrate
that contains nutrients and that does notary between tides: a veneer of
fresh mud. Wherever a mud covered bed rises above 2.0 ft. MLLW because of
gradual accumulation of sediment or from an evulsive event such as a large
flood, S a� rtina will slowly become established.
Particles suspended in sediment -laden waters that flow through such vegeta-
tion are very efficiently removed. The deposition rate is enhanced, and the
elevation of the grassy area rises rapidly at first. The frequency of flooding
diminishes, however, as the protomarsh elevation rises, until the marsh sur-
face is rarely covered by the tide. Sea level is rising a few tenths of a
foot per century, which tends to increase the frequency of marsh flooding.
-35-
The consequence of these processes is that the marsh surface elevation tends
IY to maintain itself at about mean high water (MHW).
The critical factor is the establishment of vegetation, which denends in turn
on an accumulation of substrate at elevation 2.0 ft. MLLW or above. According
to Stevenson and Emery, the existing marshes developed when clays and silts
from the Santa Ana River deposited atop old sand bars. The important factor,
however, is the elevation. Most marshes develop on mud foundations.
Transport of San Diego Creek Sediments Through Upper Newport Bay
The preceding descriptions of hydrology and transport processes laid a foun-
dation for describing transport through Upper Bay. It is convenient to
separate this description into two: one for sand and coarse silt, non -
cohesive particles, and the other for clay and fine silt, cohesive particles.
Their transport processes are nearly independent of each other.
Sediment Supply
Most of the sediment supplied to Upper Newport Bay by San Diego Creek appears
with storm runoff. Storm hydrographs have very short durations with high
peak flows. Most of the hydrograph falls typically within one or two days.
Predicted clay, silt, and sand supplied with storms under present conditions
and under ultimate conditions are shown in Tables 6 and 7. These tables show
that the sediment supply from a single 10 -year or more infrequent storm would
exceed the annual average. Under present conditions the sediment consists of
approximately 4/5 clay and silt and 1/5 sand, whereas under ultimate conditions
there will be nearly equal portions of sand, silt, and clay.
Sand Transport
Sand transported in the San Diego Creek channel is in equilibrium with the
bed. During storm flows the fine sand will be transported predominantly in
suspension. As the storm waters exit the confined channel and spread in the
upper end of Upper Bay the sands rapidly settle to the bed, and a delta -like
deposit forms. Such deposits are clearly visible in aerial photographs of
Upper Bay. Subsequent storm flows may rework such deposits, and if the flow
is sufficiently strong, channels may be maintained across the deposit.
-36-
TABLE 6
SEDIMENT SUPPLY TO UPPER NEWPORT BAY
EXISTING CONDITIONS
TABLE 7
SEDIMENT SUPPLY TO UPPER NEWPORT BAY
ULTIMATE CONDITIONS
Recurrence
Sediment
Particle
Size
Distribution
( %)
15.3
Supply
31
34
ine �oase
5 -yr. Storm
Recurrence
(1000 Tons)
Clay
Silt
Sand
Sand
76.9
29
32
36
3
25 -yr. Storm
2 -yr. Storm
12.4
60
22
17
2
5 -yr. Storm
56.8
45
38
16
1
10 -yr. Storm
109.4
41
42
16
1
25 -yr. Storm
186.0
38
44
17
1
50 -yr. Storm
353.2
37
44
17
1
100 -yr. Storm
443.4
37
43
18
1
ANNUAL AVERAGE - -
- - - -- 85.5
43
39
17
1
TABLE 7
SEDIMENT SUPPLY TO UPPER NEWPORT BAY
ULTIMATE CONDITIONS
Recurrence
Sediment
Supply
(1000 Tons)
Particle Size
Clay Silt
Distribution
Hne
Sand
%
Coarse
Sand
2 -yr. Storm
15.3
32
31
34
3
5 -yr. Storm
45.7
30
32
35
3
10 -yr. Storm
76.9
29
32
36
3
25 -yr. Storm
123.6
28
32
37
3
50 -yr. Storm
201.7
29
33
36
2
100 -yr. Storm
269.2
26
30
41
3
ANNUAL AVERAGE - -
- - - -- 64.5
30
32
36
2
-37-
v
Terrestial vegetation is already established on the sand deposit from the
1969 storm. This vegetation will slow flood flows and will further enhance
the rate of sand deposition.
Coarse silt is deposited with the fine sand, as well as a small amount of
clay. Hydraulic conditions in the broad portion of Upper Bay above "The
Narrows" are inadequate to transport sand, as shown by the present distribu-
tion of material. Under present conditions, all of the sand from San Diego
Creek is deposited in the northern end of Upper Say.
Clay and Fine Silt Transport
During the short, intense storm flows into Upper Newport Bay the freshwater
spreads over the surface of the basin above The Narrows. When the tide is
rising, the freshwater flow down the Bay is reversed. As the tide falls,
however, the flow down the Bay is enhanced by the extra water that is supplied
by the stream. The effect is more pronounced for large flows than for small
flows. The near - surface water flows through Lower Bay to the ocean.
Clay and fine silt are deposited in the upper basin when the stormwaters spread
there at moderate to high tides. A small portion of unaggregated material,
however, is carried with the fresher surface flow to the ocean during moderate
to large storms.
The fraction of the clay and fine silt that is transported directly to the
ocean during the storm event varies with the discharge. A very large discharge
would be expected to carry a large portion because the greater displacement
of saline water would occur in the upper basin. The fraction would not be
large, however, even for a large storm. The fraction approaches zero for
moderate storms.
The new deposit in the upper basin can be reworked by wave action that occurs
during windy periods. Even small waves can suspend mud when the water is
shallow. Such conditions occur near the end of a falling tide, and suspended
sediments can be carried toward Lower Bay. The stratified flows that occur,
however, would return such material to the upper basin. The bed contours in
the basin below the sand encroachment appear to be those resulting from wave
action. Resuspension by wave action tends to winnow the fines from the
deposit. Tidal currents redistribute suspended fine material into regions
where wave action is less intense.
The above description indicates that most of the fine material is deposited
in the upper basin. There is very limited information with which to verify
this conclusion. The study "Water Quality in Newport Bay and Its Watershed"
reported that 180 acre -feet of deposit accumulated in Upper Newport Bay during
the period 1973 to 1979. Most of this deposited between 2.0 and 4.0 ft. MLLW.
A total sediment supply of 277,000 metric tons of sediments were supplied
during this period, as calculated from stream records. Using the portions of
silt and clay and of sand given in Table 6, and the dry densities of the sand
deposit and in the upper basin given in the NIWA 208 study, U.C. Irvine Water
Resources Laboratory, led to the following results:
-38-
I�
Soil Total Dry Density Volume,
Fraction Amount Mass, Mt lb /cu.ft. Acre -Ft.
Silt & Clay .82 226,900 58.7 195
Sand .18 49,800 89.9 27
The loss in storage volume occurred below 4.0 ft. MLLW, so the sand deposit
at the upper end of the Bay was probably only partially included. This
calculation indicates that the fraction of clay and silt retained ranges
between 81 and 92 percent, depending on how much of the sand deposit was
included in the measured change of tidal volume.
Calculation of the volume lost between 1968 and 1977, based on maps that did
not cover the entire area led to a rough estimate that indicated that nearly
all of the material was trapped in the upper basin (NIWA 208 study).
Future Sedimentation
If the system is left as it is, there are forseeable changes that will occur.
The processes described above will continue at rates that depend on the
occurrence of storms.
Terrestial vegetation is already established on the sand deposits at the
northern end. The plants will slow stormflows that are high enough to pass
through them, and the elevation will rise after each such event. Otherwise,
the delta -like deposits will continue to encroach into the upper basin.
Clay and silt will accumulate in the basin to a depth where wave action can
erode as much material over a year as deposits there. The basin will be a
big mud flat. It is almost there. Marsh plants will become established in
areas sheltered from the wind, and elevated marshes will develop there.
These and the old marshes will absorb some of the fine sediment suspended by
wave action.
As the volume of the upper basin decreases due to the advancing sand deposit,
the developing marsh, and the rising mud flat, the volume of the tidal prism
of northern Upper Bay will diminish. Tidal currents in the channel will have
lowered maxima, and fine sediment will accumulate along channel edges,
constricting the channel cross sections until the currents are strong enough
to move any additional sediment. As the volume of the upper basin decreases,
the fraction of the clay and silt that exits to the ocean will increase.
There will probably be some accumulation of fines in Lower Bay when the amount
of silt and clay that reach Lower Bay become significant. Later, when sand
deposits have advanced to The Narrows, sand will reach Lower Bay during large
storms.
i
-39-
As the upper basin fills with sand and the channels become constricted, the
frequency of flooding the marshes with storm flows will increase. Deposition
on the marshes will remove fines, and the marsh surface elevations will rise
slowly.
Sedimentation Basins
It has been proposed that the filling of Upper Bay be halted by constructing
sedimentation basins at the mouth of San Diego Creek. Such basins could be
constructed to trap the sand and coarse silt. However, effective trapping of
clays and fine silt would require a large basin, say from the dike to Jamboree
Road. Even that basin would not trap all of the fine material from a very
large storm.
The present basin is providing excellent removal of San Diego Creek sediments.
One alternative for preserving open water would be to dredge the basin period-
ically. The sand might be useful for fill. The clay and silt, however, would
not be useful for fill unless it is dried. It would not be useful for agricul-
ture or horticulture. Disposing of such material at sea would probably be the
lowest cost option.
Conclusions
The information gathered in the Compilation Report and the description of
sediment transport given above lead to the following conclusions regarding
transport of sediments from San Diego Creek in Upper Newport Bay:
1. The sand fraction and coarse silt is retained in the northern end of
Upper Bay. It will continue to encroach on the basin above The Narrows.
2. Most of the fine silt and clays deposit in the basin north of the Narrows.
A small portion exits to the ocean at the water surface during a storm.
More than 80 percent of the clay and fine silt particles is retained in
the upper basin.
3. Marshes will develop wherever mud accumulates above the elevation of
2.0 ft. MLLW.
4. If the present situation continues, the upper basin will continue to fill
with mud and sand and its effectiveness in trapping fine sediment will
diminish.
5. Regular and systematic assessment of the progress of sedimentation is
strongly recommended.
Gfi)D
TO:
FROM:
SUBJECT:
10 60
CITY OF NEWPORT BEACH
FINANCE DIRECTOR
City Clerk
Contract No.
Description of Contract
OFFICE OF THE CITY CLERK
(714) 640 -2251
San Diego Creek Sediment Control
Facilities
Effective date of Contract Jan. 12, 1981
Authorized by Resolution No. 9959 adopted on Jan 12, 1981
Contract with Boyle Engineering
Adress 1501 quail Street, P.O. Pox 3030
Newport Beach, CA 92663
Amount of Contract $206,377.00
Wanda E. Andersen
City Clerk
WEA: bf
City I -Tall • 3300 Newport Bmilc%-ard, Newport Beach, California 92663
I 2r.
�am�)so
February 23, 1981
�.J
By rha i;;i'f C3Ui'i 1L
CITY 0r 1';_4YpOPT BEACH
TO: CITY COUNCIL
FROM: Public Works Department
CITY COUNCIL AGENDA
ITEM NO. F- r3
SUBJECT: 208 WATER QUALITY PLANNING PROGRAM -- INTERIM EARLY ACTION PLAN
RECOMMENDATIONS:
Approve a budget amendment appropriating the anticipated
State grant revenues for the project.
Authorize the staff to notify Boyle Engineering to proceed with
preparation of the plans and specifications.
DISCUSSION:
The City's 208 Water Quality Planning Study has recommended an interim
early action plan to provide sediment control protection for the Upper Newport
Bay. The work consists of.deepening the San Diego Creek channel from MacArthur
Boulevard to beyond Campus Drive; installing drop and control structures in the
channel; and dredging a basin down stream of Jamboree Road.
The State Water Resources Control Board has notified the City that a
grant of $1,000,000 of Clean Water Bond Funds has been awarded to the City for
a portion of the funding of the proposed early action plan. Concurrently, an
application for $2,000,000 of Energy Resource Funds is being reviewed for in-
clusion in the State of California budget for fiscal year 1981 -82. Final ap-
proval of these funds will not be determined until final approval of the State
budget.
In order to meet the objective of having the interim sedimentation
control facilities completed before the 1981 rainy season begins next fall, it
is necessary to start the engineering work now. It is recommended that the
plans and specifications be prepared for construction of the proposed early
action facilities. If the remaining funds are not approved, the scope of work
can be cut back accordingly prior to requesting bids.
Benjamin B. Nolan
Public Works Director
JW:jd
January 12, 1981
CITY COU
Ad)- lA/P%%2pll r�knan� Azn� ITEM NO. HL ) DA
1-
TO: CITY COUNCIL By ilia �;iiY OUNCIL
CITY Or P,EWPORT BEACH
FROM: Public Works Department
SUBJECT: ENGINEERING SERVICES AGREEMENT FOR DESIGN OF EARLY ACTION AND
INTERIM CONTROL FACILITIES, UPPER NEWPORT BAY WATERSHED
RECOMMENDATION:
Adopt a resolution authorizing the Mayor and the City Clerk to
execute the subject engineering services agreement with Boyle Engineering.
DISCUSSION:
The City's 208 Water Quality Planning Study has recommended an early
action interim plan to provide sediment control protection for the Upper Newport
Bay. The work consists of deepening the San Diego Creek channel from MacArthur
Boulevard upstream to Campus Drive and beyond; installing drop and control struc-
tures in the channel; and dredging a basin downstream of Jamboree Road.
State funding has been applied for, and it is possible that the State
Water Resources Control Board will award the funds to the City early in 1981.
In order to meet the objective of having interim sedimentation control facili-
ties completed before the 1981 rainy season begins next fall, it is necessary
to start engineering work as soon as possible. Approval of the engineering
agreement prior to approval of funds is being requested in order to minimize
delays in preparing the plans, specifications, and the necessary permit applica-
tions. However, the engineering services agreement provides that the engineering
work may not begin until written notification to start work is received from
the City.
A proposal has been requested and received from Boyle Engineering to
provide engineering services necessary to prepare plans and specifications and
to assist in the permit process. Compensation will be based on standard hourly
rates, with total fee not to exceed $206,377. The maximum fee of $206,377 is
based on the scope of work for a total project cost of $4,000,000 (Project
costs include $1,000,000 for the use of the disposal site.). If the funding
actions by the state result in the reduced alternate project cost of $3,000,000,
the maximum fee would be $163,160. A breakdown of the maximum professional fee
by principle items of work for the alternate projects is listed below.
$3,000,000 $4,000,000
Project Project
Engineering* $ 1071806 $ 131,465
Surveying 31 ,356 39,312
Computer & Reproduction Costs 3,000 4,500
Geotechnical Services 15,800 25,000
Aerial Photography 5,200 6,100
Total Fee $ 163,160 $ 206,377
*NOTE: The engineering costs listed also include a substantial allowance for
permit processing work and for environmental coordination.
January 12, 1981 4" 40
Subject: Engineering services agreement for design of early action and
interim control facilities, upper Newport Bay watershed.
Page 2
vices:
Terms of the agreement provide for the following engineering ser-
1. Surveying.
2. Geotechnical investigations.
3. Administration and coordination of the permit process.
4. Coordination with consultant preparing EIR.
5. Hydraulics and design.
6. Preparation of construction plans.
7. Preparation of contract documents and specifications.
8. Attendance at meetings and consultations during design.
9. Review of construction bids and recommendations and award
of contract.
10. Construction services including quantity calculations, inter-
pretations of contract documents, and plan revision to accommo-
date unforeseen conditions.
The projected project schedule assumes that notification to start
work will be made to the Engineer in February 1981. Key dates are as follows:
Completion of plans and specifications May 1981
Award of construction contract July 1981
Completion of work
Dec. 1981
The notice to proceed to the Engineer will be contingent on approval
of the State grant, and determination that the engineering work will be eligi-
Zfor funding u der the State grant.
Ben amin B. Nolan
Public Works Director
JW:jo
40 so
CITY OF NEWPORT BEACH
TO: Public Works Department
FROM: City Clerk
OFFICE OF THE CITY CLERK
(714) 640 -2251
Date Jan 19, 1981
SUBJECT: Contract No,
Project San Diego Creek Sediment Control Facilities
Attached is signed copy of subject contract for transmittal
to the contractor.
Contractor: Boyle Engineerin
Address: 1501 Quail Str. P.O. Box 3030
Newport Beach, CA 92663
Amount: $ 2
Effective Date: Jan. 12, 1981
Resolution No. 9959
Wanda Andersen
Attachment
cc: Finance Department
C to I fall • 3300 Ncw1)or( BoUlc•vard, Ncti-E)orl Beach, California 92663
R
AGREEMENT OR PROFESSIONAL ENGINEERING SERVICES
6ii1:
SAN DIEGO CREEK SEDIMENT CONTROL FACILITIES
THIS AGREEMENT is made and entered into this Z�J-, day of
January, 1981, by and between the CITY OF NEWPORT BEACH, a municipal corpora-
tion, hereinafter referred to as "CITY ", and the firm of BOYLE ENGINEERING
CORPORATION, hereinafter referred to as "ENGINEER."
W I T N E S S E T H
WHEREAS, the CITY is performing the 208 Sediment Control Study for
the Upper Newport Bay Watershed; and
WHEREAS, the Study has recommended early action and interim plan
facilities for the Upper Newport Bay which consist of deepening the San Diego
Creek Channel from MacArthur Boulevard to approximately 2,400 feet north of
Campus Drive; installing drop structures, weirs, and low -flow drainage
systems in the Channel; and dredging downstream of Jamboree Road; said im-
provements are hereinafter referred to as "PROJECT "; and
WHEREAS, the CITY desires to prepare plans and specifications for
the construction and implementation of the PROJECT; and
WHEREAS, ENGINEER has submitted a proposal to CITY (dated December
1980) to perform engineering services necessary for the preparation of plans
and specifications for the PROJECT; and
WHEREAS, CITY desires to accept said proposal;
NOW, THEREFORE, in consideration of the foregoing, the parties
hereto agree as follows:
I. General
A. CITY engages ENGINEER to perform the services hereinafter
described for the compensation herein stated.
B. ENGINEER agrees to perform said services upon the terms
hereinafter set forth.
II. Notice to Start Work
ENGINEER agrees that no work under this agreement shall begin
until written notice to begin work is received from the CITY.
The CITY reserves the right to terminate this agreement prior
to the notice to start work.
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9
III 4Services to be Performed by EN"
R
A. Field surveys necessary to establish controls, estimate
quantities and to prepare plans.
B. Geotechnical investigation including sufficient information
for design and informed bidding. The soils investigation
should include site "A ", the area north of and adjacent to
Jamboree Road, with recommendations for the placement of
dredge and /or in- channel materials.
C. Engineering support to aid in obtaining permits from various
agencies, including preparation of exhibits, estimates and
attendance at meetings.
D. Engineering services and support in coordination with the
preparation of an environmental impact report by a separate
consultant.
E. Engineering services necessary for hydraulic calculations
and design.
F. Preparation of two sets of construction plans: one set of
plans for Contract I, the work in San Diego Creek; and one
set of plans for Contract II, the dredging and /or excava-
tion south of Jamboree Road.
G. Preparation of two sets of contract documents, specifica-
tions, proposals and construction cost estimates which
correspond to the construction plans. Incorporate the
CITY's standard specifications, "Standard Specifications for
Public Works Construction, 1979 Edition," in the project
specifications.
H. Attendance at meetings with CITY staff and other agencies
as necessary to review progress of design and plan prepara-
tions.
I. Engineering services to assist CITY in reviewing construc-
tion bids and making recommendations for award of contracts.
J. Construction services including quantity measurements and
calculations, interpretation of contract documents, and
plan revisions to accomodate unforseen conditions.
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IV. Duties of CITY
A. Provide mylar plan and profile and standard sheet for
preparation of the plans.
B. Reproduce the necessary copies of the contract documents
and specifications.
C. Provide contract administration and inspection for the two
contracts.
V. Time of Completion
The following PROJECT schedule assumes that the notice to start
work will be given by February 6, 1981. Delays in the notice
to start work shall be applied directly to the dates in the
PROJECT schedule.
Completion of plans and specifications May 22, 1981
Advertise May 29, 1981
Award of contract(s) July 24, 1981
Completion of construction contracts Dec. 18, 1981
VI. Ownership of PROJECT Documents
Original drawings, reports, notes, maps, and other documents
shall become the property of the CITY and may be reproduced and
utilized as deemed necessary by the Public Works Director.
Any use of the aforesaid completed documents for other projects
without specific, written approval by ENGINEER will be at CITY'S
sole risk and CITY shall indemnify and hold harmless ENGINEER from
all claims, damages, losses and expenses, including attorney's fees,
arising out of or resulting therefrom.
VII. Right of Termination
CITY reserves the right to terminate this agreement at any
time by giving ENGINEER seven (7) days' prior written notice;
notice shall be deemed served upon deposit in the United States
Mail, postage prepaid, addressed to the ENGINEER's business
office at 1501 Quail Street, P. 0. Box 3030, Newport Beach,
California 92663. In the event of termination due to errors,
omissions, or negligence of ENGINEER, CITY shall be relieved of
any obligation to compensate ENGINEER for that portion of the
work affected by such errors, omissions, or negligence of the
ENGINEER. If this agreement is terminated for any other reason,
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F
O CITY agrees to compensate ENGINEER for the actual services per-
formed up to the effective date of the notice of termination,
on the basis of the fee schedule contained herein.
VIII. Fee Schedule and Payment
In consideration of the performance of the above - described
engineering services, CITY hereby agrees to pay ENGINEER an
amount based upon the hourly rate schedule set forth below.
In no event shall said amount be greater than Two Hundred Six
Thousand Three Hundred Seventy -seven Dollars ($206,377.00)
except as otherwise provided herein.
A. Hourly rates for office and field personnel shall be as
follows:
CLASSIFICATION
Consulting Engineer /Architect
Principal Engineer /Architect
Senior Engineer /Architect
Associate Engineer /Architect
Assistant Engineer /Architect
Senior Technician
Technician
Senior Drafter
Drafter
Licensed Surveyor
Three -man Survey Party
Two -man Survey Party
Electronic Distance -- Measuring Equipment
Clerical
RATE
$ 69.00 /hour
$ 60.00 /hour
$ 52.00 /hour
$ 43.00 /hour
$ 35.00 /hour
$ 36.00 /hour
$ 34.00 /hour
$ 30.00 /hour
$ 25.00 /hour
$ 50.00 /hour
$117.00 /hour
$ 80.00 /hour
$120.00 /day or
part thereof
$ 18.00 /hour
It should be noted that the foregoing wage rates are effec-
tive through December 31, 1981. The rates will be adjusted
after that date to compensate for annual labor union nego-
tiated adjustments or other increases in labor costs.
B. The contract amount shall be paid to ENGINEER as follows:
1. Monthly partial payments shall be based on the amount
earned each month, as determined by the fee schedule.
2. In addition, CITY agrees to reimburse ENGINEER for the
actual costs advanced for outside services contracted
by the ENGINEER and for actual costs of reproduction,;
and computer services, and other related costs authorized
in advance by the Public Works Director.
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IX. Additional Work
X
XI
XII
Should ENGINEER complete any additional work not outlined in
this agreement, but authorized by CITY, the extra work shall be
performed on an hourly basis in accordance with the hourly rate
standard fee schedule set forth in Section VIII (Fee Schedule
and Payment) above.
PROJECT Scope Revisions
The scope of the PROJECT may be changed and the maximum fee
revised upon prior written approval of the Public Works Director
if the increase in the maximum fee does not exceed Twenty
Thousand Dollars ($20,000.00). If the increase in the maximum
fee should exceed $20,000.00, an amendment providing for such
revisions shall be processed and excuted by the parties hereto.
Contractor's Indemnification
The CITY will require that any Contractor performing work in con-
nection with the construction contract documents produced under
this Agreement to hold harmless, indemnify and defend the CITY,
the ENGINEER, their consultants, and each of their officers,
agents and employees from any and all liability, claims, losses
or damage arising out of or alleged to arise from the Contractor's
negligence in the performance of the work described in the con-
struction contract documents, but not including liability that may
be due to the sole negligence of the CITY, the ENGINEER, their
consultants or their officers, agents and employees.
The CITY will require the Contractor to provide comprehensive
general liability insurance with the latter coverage sufficient
to insure the Contractor's indemnity, as above required; and,
such insurance will include the CITY, the ENGINEER, their con-
sultants, and each of their officers, agents and employees as
additional insureds.
Hold Harmless
ENGINEER shall indemnify and save harmless CITY and its officers
and employees from any damage or liability arising from any
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` • rrors, omissions, or negligence the ENGINEER's performance
of the engineering work and services required by this agreement.
IN WITNESS WHEREOF, the parties hereto have executed this agreement
on the date first above written.
ATTEST:
By
City Clerk
CITY OF NEWPORT BEACH
BOYLE ENGINEERING CORPORATION
WA
APPROVED AS TO FORM:
BY b lJ -..
City Attorney
Managing Engineer`. j ENGINEER
BY
Regional Vice President ENGINEER
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so
RESOLUTION NO.
99,59
A RESOLUTION OF THE CITY COUNCIL OF NEWPORT
BEACH AUTHORIZING THE MAYOR AND CITY CLERK TO
EXECUTE AN AGREEMENT BETWEEN THE CITY OF
NEWPORT BEACH AND BOYLE ENGINEERING IN CONNEC-
TION WITH ENGINEERING SERVICES FOR THE DESIGN
OF EARLY ACTION AND INTERIM CONTROL FACILI-
TIES, UPPER NEWPORT BAY WATERSHED (208 STUDY)
WHEREAS, there has been presented to the City Council of
the City of Newport Beach a certain Agreement between the City of
Newport Beach and Boyle Engineering in connection with
engineering services for the design of early action and interim
control facilities, Upper Newport Bay Watershed (208 Study); and
WHEREAS, the City Council has reviewed the terms and
conditions of said Agreement and finds them to be satisfactory
and that it would be in the best interest of the City to execute
said Agreement,
NOW, THEREFORE, BE IT RESOLVED by the City Council of
the City of Newport Beach that the Agreement above described is
approved, and the Mayor and City Clerk are hereby authorized and
directed to execute the same on behalf of the City of Newport
Beach.
ADOPTED this 12th day of January, 1981.
Mayor
ATTEST:
City Clerk kv
010681