HomeMy WebLinkAboutAlternative Proposals for Flood Control and Allied Purposes i
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The alternative
solutions presented are
conceptual in nature.
Whichever plan is
ultimately selected will
require detailed engi -
neering study.
1 ,Tune 1973
SANTA ANA RIVER BASIN AND ORANGE COUNTY, CALIFORNIA
Status Report on Flood Problems along the
Santa Ana River and Principal Tributaries
in Orange, Riverside, and San Bernardino
Counties, California
Los Angeles District, Corps of Engineers
The current Santa Ana. River Basin and Orange County study covers about
3,200 square miles. It includes the portions of San Bernardino and
Riverside Counties that are in the Santa Ana River drainage area and
all of Orange County.
The review report for Santa Ana River Basin and Orange County was
authorized by Resolution of the Committee on Public Works, House of
Representatives, adopted 8 May 1964. The first public meeting was held
on 10 February 1965 in Riverside, California.
The Santa Ana River Basin study is a review study of previous reports
on the Santa Ana River Basin. Various projects built as a result of
previous studies are: Brea, Fullerton, and Carbon Canyon Dams, Prado
Reservoir, San Antonio Dam, San Antonio and Chino Creeks Channel,
improvements on Lytle and Cajon Creeks, Devil East Twin Warm and Lytle
Creeks, City Creek Levee, Mill Creek Levee, and San Jacinto River and
Bautista Creek near Hemet. A channel improvement project is under
construction for Lytle and Warm Creeks and the confluence area of the
Santa Ana River near Colton. Under separate authorization are: Cucamonga
Creek improvements, and University Wash and Spring Brook near Riverside.
Both are in General Design Memorandum stage.
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GENERAL INVESTIGATIONS
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�4�/. - . SURVEYS—FLOOD CONTROL
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m; SANTA ANA RIVER BASIN
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33,020- 33-20- SOUTH PACIFIC DIVISION
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There are several important flood problem areas within the basin currently
under active study. One of the major existing flood control works in the
Santa Ana River Basin is Prado Reservoir, just west of Corona, California..
The dam and reservoir were completed by the Corps of Engineers in 1941.
The facility was designed in the 1930's to control floods up to the size
of flood that would be reasonably expected to occur under anticipated future
development of the watershed. Its purpose is to provide protection to a
large flood plain in Orange County, including portions of the cities of
Anaheim, Orange, Fullerton, Buena Park, Garden Grove, Santa Ana, Fountain
Valley, Westminster, Huntington Beach, and Costa Mesa.
Prado Reservoir, when completed in 1941, had a storage capacity to spillway
crest (elevation 543 feet) of 223,000 acre-feet. The reservoir is operated
normally dry so that its capacity is available to regulate floodflows. In
the past 30 years, the reservoir capacity has diminished 11 percent to
198,000 acre-feet because of sediment deposition. The total reservoir area.
with a guide property-taking line based on elevation 556 is about 9,741 acres.
In our current review investigation, using more reliable methods of computing
runoffs, and reflecting much more intensive urbanization of the drainage
area than was conceived in the late 1930's, we find that neither Prado
Reservoir nor the Santa Ana River downstream could contain the large floods
that we expect to occur. With today's development of the watershed, the
Standard Project Flood, a flood magnitude frequently used for design of
urban flood control improvements would, with the present reservoir capacity,
result in large, uncontrolled spillway flows that would breach the Santa
Ana River levees near Anaheim and flood about 100,000 acres in the Orange
County urbanized flood plain. Total damages to homes, businesses, indus-
tries, transportation, work lost, and other economic entities would be an
estimated $2,200,000,000 under 1973 conditions of development. As time
goes on, this amount would increase due to more intense development in the
flood plain, further upstream urbanization, and shrinking reservoir capacity.
The existing level of protection is such that the odds are about 1 in 70
each season of uncontrolled flows going over Prado Dam spillway, and about
1 in 35 for the Santa Ana River channel capacity being overtaxed in spills
from Prado Reservoir or by tributary drainage in the urban areas of Santa
Ana, Fountain Valley, Costa Mesa, or Huntington Beach.
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Remedies for alleviating the flood hazard in the lower Santa Ana River
flood plain range from greatly increasing upstream reservoir capacity at
one or more reservoirs plus moderate improvement of the 31 miles of
channel downstream, to keeping the same reservoir area and volume, but
greatly widening the channel downstream. Other alternatives are in between.
In all plans of reservoir modification and channel improvement, collectively,
we want to incorporate the best mix of water conservation, water quality,
fish and wildlife, diversified recreation, flood control and, all-in-all,
a quality environment.
Some of the pertinent data on size of the improvements, numbers of
properties affected, and project costs for several plans of improvement
on Prado Reservoir, an upstream reservoir, lower Santa Ana River channel,
and Santiago Creek are given in the following table. The subsequent
discussion is relative to salient features of various plans in a comparative
analysis.
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PRADO RESERVOIR LOWER SANTA ANA RIVER SANTIAGO CREEK AND MENTONE RESERVOIR -.PRINCIPAL PLANS OF IMPROVEM-NT 3 May 1973
Prado Reservoir Enlarged Prado Reservoir not
ed to Control Standard Project Flood es
Existing g Enlarged, Dam Modified
Project Dam � -- � � y� � � �- ' � La e Channel Downstream
Completed odification With Upstream Reservoir -
Plan p No Upstream Reservoir at Mentone Site Wide Greenbelt
in 1941 only , Flood Control
Channel Park Plan
-- ( 1 ) (2) --(3) (4) (5) (6) (7) (8) (9) ( 10)
Prado Reservoir
Design release, cubic feet per second. . . . . . . . . . . . . . . . . . , 5,000 200,000 20,000 40,000 60,000 20,000 40,000 60,000 abt.200,000 200,000
Water level design flood, ft. msl . .. . . . . . . . . . . . . . . . . . . . 543 556 580 574 569 569 562 556 556 556
Storage capacity, gross, acre-feet. . . . . . . . . . . . . . . .. . . . . 198,000 295,000 573,000 495,000 435,000 435,000 350,000 295,000 295,000 295,000
Land area gross, acres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,741 9,760 15,700 14,200 13,000 13,000 11 ,300 9,760 9,760 9,760
Additional land required, acres . . . . . . . . . . . . . . . . . . . . . . . . 0 19 abt. 6,000 4,500 3,300 3,300 1,600 19 19 19
Developed land, agric. and homes . . . . . . . . . . . . . . . .. . . . . 0 (0) (5, 100) (3,800) (2,800) (2,800) ( 1,200 (0) (0) (0)
Streambeds and hillsides . . . . . . . . . . . . . . . . . . . . . . ... . . . . . 0 ( 19) (900) (700) (500) (500) (400) 19) ( 19) ( 19)
Number of homes displaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 0 620 410 230 230 90 0 0 0
Number of dairies displaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 0 54 I 42 32 32 17 0 0 0
Dams (and dikes) top elev. ft. msl . . . . . . . . . . . . . . . . . . . . . 566 577 589 583 579 579 577 576 577 577
Lower Santa Ana River Channel
Land needed, acres
Santa Ana Canyon, 7-1/2 miles. . . . . . . . . . . . . . . . . . . . . . . . . None held - 1 ,600 1 ,650 1 ,690 1 ,600 1,650 1 ,690 1 ,830 1 ,830
Urbanized reach, 24 miles . . . . . . . . .. . . . . . . . . . . . . . . . . . . .
Total required. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,650 1,650 1 ,740 1 ,850 2,050 1 ,740 1,850 2,050 2,970 4,800
Increment needed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - 90 200 400 90 200 400 1 ,320 3, 150
Number of homes displaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 0 90 240 670 90 240 670 2,600 7,200
Number of bridges rebuilt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 0 13 25 33 13 25 33 35 35
Project Costs ($ 1 ,000,000) - Assuming 1973 prices and 1973
land acquisition without projected improvements
Prado Reservoir
Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 35 33 32 31 30 30 30 30
Rights-of-way. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . - 126 97 73 73 31 - - -
Relocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 17 � 33 10 10 4 1 1 1
Subtotal .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 31 178 143 115 114 65 31 31 31
Downstream Channel
Santa Ana Canyon Reach
Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 3 2 2 3 6 6
Rights-of-way. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10 12 9 10 12 18 18
Relocations. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 1 2 2 1 2 2 3 3
Subtotal .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 12 14 17 12 14 17 27 27
Urbanized Reach
Construction.. . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . .. . . . . 67 81 93 67 81 93 126 100
Rights-of-way. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . 11 13 21 II 13 21 145 410
Relocations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. .. .. .. 12 23 34 12 23 34 57 100
Subtotal .. . . . . . . . . . . . . . . . . . . . . . . . . . .. 0 . . . 0 90 117 148 90 117 148 328 610
Santiago Creek
Construction. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . .. 9 9 9 9 9 9 9 9
Rights-of-way.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 2 2 2 2 2 2 2 2
Relocations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . 2 2 2 2 2 2 2 2
Subtotal . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. OI 13 13 ` 13 13 13 13 13 I 13
Upstream Mentone Reservoir i
Construction. . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 130 130 130
Rights-of-way. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . i
12 12 12
Relocations. . . . . . . . . . . I 3 3 3
. . . . . . . . . . . . . . .. . . . . .... . . . . . .
Subtotal .. . . . . . . . . . . . . .. . . . . . .. . . .. . . . .. 145 145 145
rand total . ( 31 293 287 293 374 354 354 399 681
Plan 1 - Do nothing - no Federal project.
Description - Live with existing Prado Reservoir that we have had 32 years,
and the limited Santa Ana River channel improvements that Orange County has
been able to build. Then a standard project flood under today's conditions
would inundate 100,000 acres and cause damages and losses estimated at
$2 200z000,000. A one-chance-in-100 flood would result in about $330,000,000
an nnundate 27,000 acres mostly south of the Garden Grove freeway.
Advantages:
1. Does not involve large expenditures of funds by local interests or
Federal Government; local bond issues not required, and does not soak up
California's share of river-basin improvement for several years.
2. No controversies over which properties are displaced for a project.
3. Fewer environmental problems.
Disadvantages:
1. Large catastrophe potential, over 11000,000 people affected, trans-
portation and business interrupted.
2. Threat becomes worse as whole Santa Ana River basin develops.
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Plan 2 - Just raise Prado Dam.
Description - Raise Pra.do Dam 10 to 12 feet, rebuild the spillway so as
to pass the probable maximum flood to avert the hazard of an extremely
large flood overtopping the dam. Do not enlarge the reservoir.
Variations of the Plan:
1. Modify the dam so as to utilize the storage capacity we have to
better advantage and gain a slightly better level of flood protection.
2. Acquire Santa Ana Canyon right-of-way down to beginning of
Orange County's improved channel to accommodate normal releases of the
dam. Under current policy, local interests would have to pay for rights-
of-way and relocations, $10,000,000 at 1973 prices.
Advantages:
1. Avoids the catastrophic potential of a dam being overtopped
and possibly washing out.
2. A slightly better degree of reservoir control.
3. No developed properties displaced.
4. Requirements for 1 cal funds small - none-(or relatively small in
variations of plan.
Disadvantages:
1. During the very large floods catastrophic potential just about
as large as with present facilities.
2. With this limited project, possibly the opportunity is lost for
a better project.
-8-
Plan 3 - Great enlargement of Prado Reservoir plus some downstream channel
enlargement.
Descri tion: Raise high water .limit line from elevation 556 feet up to
580 (24 feet rise). Elevation 580 is the high water level for a standard
project flood occurring 100 years from now at end of project life. (For
beginning of project life the maximum might be 570 feet. ) Release from
the dam is 20,000 cubic feet per second. Reservoir is expanded about
6,000 acres:
4,500 acres agricultural
300 in homes mostly Corona and Norco
300 " industrial
900 streambeds, hills, ravines
Total. . . . 6 000 " (3,200 in Riverside Co. ; 2,800 in San Bernardino Co.
Variations:
1. Dikes to contain the larger storage in a smaller area.
Drawbacks:
a. 50 feet high - they block the skyline.
b. Ponding areas required on uphill side of dikes.
c. Higher water level in the undiked areas.
2. Spillway Options:
a. Gated - offers more flexibility in reservoir operation.
b. Ungated - similar to present spillway, but spillway must
be raised and widened, requires a dam 20 feet higher than with gated spillway.
3. Full debris allowance for 100 years, elevation 580 feet.
Partial debris allowance for one flood, elevation 577 feet, may
require a big, 2-year cleanout operation and disposal sites for 60,000,000
yards of silt.
Multiple Use - With extra storage at beginning of project life:
1. More water can be conserved.
2. A recreational lake can be formed.
Downstream Channel:
1. Santa Ana Canyon - probably retain it in its natural state with
some revetment to protect the freeways and railroad.
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2. Imperial Highway to Anaheim Stadium - use existing channel wit"n
small alteration.
3. Santa Ana Freeway to San Diego Freeway - probably a concrete channel,
but avoid taking homes.
4. Below San Diego Freeway to ocean - soft-bottom channel, widen
existing channel about 200 feet.
Bridges rebuilt are mostly downstream from 17th Street, Santa Ana.
Advantages:
1. Provides standard project flood protection.
2. Plan utilizes much of the existing channel and displaces few homes
in Orange County.
3. Fewer bridges have to be rebuilt.
4. Large storage capacity of Prado Reservoir provides multiple
benefits with a large recreational area.
5. Has smaller cost-sharing for Orange County, about $37,000,000 at
1973 prices (including improvements on Santiago Creek).
Drawbacks
1. Displaces homes and properties around Corona and dairies north of
river.
2. Taxes and jobs foregone in reservoir area.
3. Slows down sand movement to the beaches.
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Plan 4 - Partial enlargement of Prado Reservoir. Wider channel downstream.
Description: Raise Prado Reservoir 18 feet instead of 24 feet. Rebuild
dam, spillway and add outlet works. Release the water faster - 40,000 c.f.s.
Variations and options, such as perimeter dikes, spillway-type, debris
allowance and multiple use as with larger reservoir.
Downstream stream channel:
Similar to Plan 3 but wider. _
Water-spreading area between Imperial Highway and Anaheim Stadium
must be narrowed to allow for more channel.
Homes displaced in vicinity of San Diego Freeway and downstream.
Strong Points:
1. A good compromise between properties displaced in the reservoir
area and the downstream channel strip.
2. Probably the least overall number of homes and establishments
displaced.
3. Prevents the taking of many newly-built fringe properties around
Corona and Norco.
Disadvantages:
1. Less reservoir storage compared to Plan 3.
2. Santa Ana Canyon flooding more severe with larger releases.
3. More homes taken below 17th Street Santa Ana and more bridge
rebuilding.
4. Higher local cost-snaring $52,000,000.
11:iri 5 - Partial enlargement of Prado Reservoir, 60,000 c.f.s. released.
Descrint'on - Raise r'r,.do Reservoir about 13 feet. Still wider channel
downstream.
::dva.T_ta.ges card es similar to Plan 4,.but different in degree.
Miscellaneous Features:
Nearly ali downstream bridges must be rebuilt.
b'cre home:: are taken south of Garden Grove Freeway.
Prob�ljl:;r two sewer plants in the lower 5 miles must be substantially altered.
Local coot-sharing - $73,000,000.
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Plan 6 - Build an upstream reservoir on Santa. Ana River near Mentone,
plus enlarge Prado Reservoir about half-way. Release 20,000 c.f.s. from
Pi-ado. The downstream channel is common to Plan -3.
Advantages:
1. Saves the taking of more than half of the homes around Corona
which would be taken with Plan 3.
2. Prado Reservoir is about the same size with upstream dam plus
20,000 c.f.s. release from Prado Dam as it would be with Prado Reservoir
enlargement alone plus 60,000 c.f.s. release, (Plan 5) .
3. Few homes are displaced in the upstream reservoir.
4. Local benefits from:
a. Flood damages reduced in south San Bernardino and Colton.
b. Open space recreation in the upstream reservoir.
c. Some water conserved on rare occasions.
5. Savings in cost at Prado Reservoir around $70,000,000.
6. Would tie in well with an improvement of Mill Creek levee.
Draeroacks:
1. Difficult to find an efficient site for alternate storage.
2. The large dam may cause changes in the local microclimatoloor; also
the open riverbed view toward the Santa Ana Canyor: would be obstructed.
3. The upstream reservoir is not quite incrementally justified,
about 0.8 to 1 benefit-cost ratio.
4. The dam would be in an earthquake-fault area.
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Pertinent information on the upstream reservoir site northeast of Redlands,
near Mentone, is as follows:
Maximum Land and
water Area relocation
level Gross of Total portion
at Prado storage land cost cost
Millions
Feet Acre- of
m.s.l. feet Acres dollars
Without big upstream
dam. . . . . . . . . . . . . . . . . . . . 580 573,000 -15,700 178 (143)
With dam. . . . . . . . . .. . . . . . . 569 435,000 13,000 114 (83)
Difference. . . . . . . . . . . . . . . 11 1381000 2,700 64 (63)
Some of the pertinent data on the upstream dam being studied is as follows:
Crest length. . . . . . . . . . . . . . . . . . . . . . . 18,000 feet
Dam top elevation. . . . . . . . . . . . 1,760 "
Streambed elevation (in middle). . . . 1 460 "
Dam height. . . . . . . . . . . . . . . . . . .. . . . . . 300 "
Volume of dam. . . . . . . . . . . . . . . .. .. .. . 90,000,000 cubic yards
Spillway type - Ungated, concrete, cut into bluff on north just
below Plunge Creek, crest elevation 1,735
Outlet type - Gated conduit toward north end of dam
Standard project flood peak inflow - 130,000 c.f.s.
Outflow during flood (range) - 2,000 to 10,000 c.f.s.
Reservoir storage capacity at spillway crest - 200,000 acre-feet
Net storage after debris accumulation - 140,000 acre-feet
Reservoir Gross Area - 2,100 acres
Agricultural land-citrus - (600) acres
Streambed - (1,500) acres
As to supplementary storage in upstream sites above Prado Reservoir, many
sites showing promise of potential have been considered. Other sites listed
generally in descending order of flood reduction effectiveness at Prado
include those along Lytle and Cajon Creeks, upper Santa Ana River, Mill
Creek, San Timoteo Creek and Tributaries, Temescal Wash, Lake Elsinore, and
alternative sites on the Santa Ana River itself. Some of these sites were
studied more than 40 years ago.
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Plan 7 - Combine upstream reservoir with Prado Reservoir sized for 40,000
c.f.s. outflow plus channel improvement downstream.
Features - Prado Reservoir would only have to be raised about 6 feet to
elevation 562. The plan results in the least overall number of homes and
properties displaced.
Plan 8 - Combine upstream reservoir with 60,000 c.f.s. out of Prado
Reservoir and appropriate downstream channel.
Features - Prado Reservoir would not have to be enlarged, but Prado Dam
would be raised 10 to 12 feet and the spillway rebuilt. Nearly all pro-
perties displaced would be downstream along the Santa Ana River in
Orange County.
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Plan 9 - All-channel Plan 1.
Description: Keep existing Prado Reservoir. , raise dam, and rebuild spill-
way similar to Plan 2. No upstream reservoir. Downstream channel must
be wide to accommodate large unpredictable outflows from Prado Dam -
around 200,000 c.f.s.
1. Santa Ana Canyon - revetment, expect heavy damages anyway when
large spillway flows come.
2. Water-spreading area near Imperial Highway. Wide single channel,
about 300 feet additional width required.
3. Santa Ana Freeway to San Diego Freeway - 200 to 300 feet more
width needed.
4. Below San Diego Freeway, about 500 feet more width needed.
Variation: Keep the channel within existing right-of-way but make it deeper.
Difference - near the San Diego Freeway, levee heights would be 30 feet
instead of present 14 feet. Bridge ramps must also be longer.
Advant Pes:
1. No properties displaced at Prado Reservoir and upstream.
2. Much recreational area available in wide downstream channel.
Drawbacks
1. Displacement of downstream properties - 2,600 homes plus
industries.
2. Relocations - all bridges rebuilt, major pipelines torn out and
moved, two sewer plants completely rebuilt.
3. Greater overall cost than with full or partial increase in
reservoir-storage capacity.
4. High local cost-sharing for channel - $227,000,000.
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Plan 10 - Greenbelt all-channel plan 2 variation of Plan 9. Raise Prado
Dam - no reservoir enlargement, proposed by environmental advisory committee.
Descri-otion: In the urban area, use the existing charnel for smaller floods.
Make a wide secondary channel for the large overflows. Contain, the whole
channel by levees. `The channel forms a continuous park for many recreational
activities--golf, riding, hiking, baseball, picnicking, camping, etc.
'The plan requires great widths of land - about
1,400 feet at Imperial Highway
1,700 It it the Santa Ana. Freeway
1,90' " San Diego Freeway and southward to the
river mouth.
Variation: The plan is adaptable in smaller scale for smaller releases
from Pra.do Reservoir also.
Advantages:
1. No upstream properties displaced.
2. Very large recreational area - about 4,800 acres in Orange County.
Drawbacks:
1. Displacement of existing development in about 3,100 acres, over
7,000 homes, many industries.
2. Heavy relocations of bridges, utilities, and sewer plants.
3. Total project not economically justified.
4. Great local cost, about $ 540,000,000. How to raise the money is
not apparent.-
-16-
SANTIAGO CREEK IMPROVEMENTS
The existing Santiago Creek enters urbanized Orange County from the north-
east into the City of Orange. It flows westward through the City of Santa
Ana and enters the Santa Ana River about 1 mile south of the Garden Grove
Freeway crossing. The existing stream course is partially improved through
most of the urban area. Because of the well-entrenched condition of the
creek throughout most of the 8-mile urban reach, a standard project flood
would not be expected to inundate large areas similar to those of a break-
out from the Santa Ana River. However, the several hundred homes which
would be damaged would be damaged severely.
An uncontrolled 50-year flood would be expected to inundate a relatively
narrow width, two or three blocks in the westernmost 2 miles in Santa Ana,
but the few properties affected would suffer substantial damage, as in
February 1969. Because of the relatively limited benefits from flood
damages prevented, the constraints of economic justification necessitate
certain limits in the cost of improvements. Standard project protection
probably cannot be economically justified. Perhaps the weaker portions
could be upgraded to a 100-year flood capacity.
With available guidelines from environmental advisory committee suggestions and the
Orange County Santa Ana Santiago Creek Breenbelt Plan published in 1971,
certain improvements might be incorporated, such as:
a. From the upstream reaches a larger capacity opening at the
Collins Avenue-Prospect Avenue bend.
b. Adding several feet of height and strengthening the existing
channel slopes in the vicinity of Chapman Avenue, making sure the work
blends in with the beauty of the surroundings.
c. Minor revetment to insure control of Santiago Creek in the Santiago
golf course area.
d. Utilizing the existing channel in the Hart Park area and Santiago
Park area.
e. Increasing bridge capacity at Main Street, Santa Ana Freeway;
SPRR, Flower and Bristol Avenues to permit full use of existing channel
width.
f. A concrete channel from about the Santa Ana Freeway to the Santa
Ana River confluence to fit the existing right-of-way.
g. Inclusion of riding and hiking trails along Santiago Creek from
the Santa Ana River up to unurbanized areas far upstream.
The cost estimate in the table is based on partial improvement of Santiago
Creek within economic constraints.
-17-
Other Improvements Under Study in the Santa Ana River Basin - In addition
to consideration of improvements on Prado Reservoir, lower Santa Ana River,
the upstream reservoir near Mentone and Santiago Creek; other problem
areas are currently under active study. These include improvements for
Temescal Wash in north and east Corona, Oak Avenue Drain in West Corona,
San Timoteo Creek at Loma Linda, the Mission-Zanja in Redlands, and Wilson
Creek in the Dunlap Acres section of Yucaipa. Other improvements in the
downstream portions of the basin include channelization and basin modifica-
tions along Upper Coyote Creek in the vicinity of La Habra, Brea Creek at
Fullerton, Fullerton Creek at Fullerton, and Carbon Creek which passes
through Anaheim.
Other streams in three counties are to be studied later.
Riverside County
Of interest in the Corona area, as mentioned, is improvement of the Temescal
Wash to avert heavy damages to many industries, businesses, and some homes.
Damages resulted from '1969 floods. Total damages amounted to about $4,500,000
at 1969 prices and levels of development. One of the principal alternatives
of improvement under consideration is a concrete channel extending from the
canyon mouth of Temescal Wash about 3 ,.miles southeast of central Corona and
running about 5 miles westward into Prado basin in the vicinity of the
Corona airport. The hazard area has diversified industries and businesses
including a shopping center across Main Street. It would be desirable to
have channelization compatible with existing,recently constructed,improve-
ments by Riverside County in the lower half of the reach and within the
available right-of-way.
A corollary improvement would be channelization of Arlington Wash
which enters Temescal Wash from the east at about the Riverside Freeway
overerossing. The channel may be only 1 mile long because economic justi-
fication of several miles of channel Farther eastward into the Arlington
Valley area of Riverside appears doubtful.
In the western part of Corona heavy damage also occurred in the 1969 floods.
Rapid flows and debris came down from headwaters originating in canyons
of Corona causing damage to citrus lands, streets, a labor camp, houses,
apartments, businesses along 6th Street, and a few industries. Total
damages were about $1,400,000. An improvement alternative would consist
of a. basin or inlet levees at the junction of Tin Mine and Hagador Canyons
about 3 miles south of Corona, then a channel extending northward through
Corona into Prado Reservoir in the vicinity of the Alcoa aluminum plant.
A debris basin is under study by Riverside County for Mabey Canyon.
Possibly a channel connection to the main north-south channel along the
Oak Avenue route will be included.
Also of interest to Corona vicinity residents is the type of enlargement,
if any, recommended for Prado Reservoir. It is noted that elevation 580
reaches almost to North Main Street at the shopping center.
-18-
San Bernardino County
In the Loma Linda area, improvement is being studied for San Timoteo Wash
from about the San Timoteo Canyon Road crossing in southwest Redlands down
to the confluence with the Santa Ana River near Waterman Avenue. A type
of improvement which appears suitable for controlling floods and utilizing
the available channel width would consist of inlet levees at the San
Timoteo Canyon mouth and a strong, concrete channel along a 5-1/2-mile
reach through Loma Linda along the existing channel route. The 1969 floods
inundated orange groves, hundreds of homes and many business establishments.
Four bridges were destroyed, two more were heavily damaged,and many streets
were made impassable with debris. One youth was drowned. Monetary damage
totalled about $6,300,000. A public advisory committee for improvement of
San- Timoteo Creek will probably be formed in July 1973.
In the Redlands area, a principal source of flooding is the Mission-Zanja.
This is a creek originating to the east in the Crafton Hills area. The
creek passes through the downtown Redlands shopping area and westward to
the Santa Ana River near Tippecanoe Avenue and the Tri-City Airport. A
meeting was held in Redlands on 25 April 1973 to form a public advisory
committee to improve the Zanja. It is the wishes of most people to
preserve the park-like portion of the creek in east Redlands. Any channel
to control floods, if found to be economically feasible, would probably
consist of a channel along railroad tracks, a culvert portion through the
downtown, and open-type channel improvement along the existing channel aline-
ment,-,west of downtown.
In the Dunlap Acres portion of west Yucaipa, Wilson Creek, which originates
in the Oak Glen area, flooded the residential area both in January and
February 1969. The latter flood was worse. The flood moved large amounts
of silt and gravel and flooded a school, about 200 homes, orange groves,
two churches, a trailer park, two restaurants, a bar, and a truck and heavy
equipment yard. Large piles of sediment had to be removed from streets
and hauled away. Because of the debris potential and steep stream slopes,
an improvement may consist of a. debris basin upstream of Yucaipa Boulevard
leading into a vertical-walled concrete channel extending about 2-1/2
miles down just past the crossing of the I-10 Freeway.
Other Improvements in the Santa Ana River Basin - Post authorization studies
for the improvement-of Cucamonga, Deer Creek and tributaries in the vicinities
of Upland, Ontario, and Cucamonga are in advanced design studies. Cucamonga
Creek flows southward from the San Gabriel Mountains to Prado Reservoir. A
public meeting was held in Ontario 1 May 1973.
Farther east, studies are under way for debris structures and channeliza-
tions for Day, East Etiwanda and San Sevaine Creeks in the vicinities of
Etiwanda, Fontana, and Mira Loma (Riverside County).
The upper Warm Creek studies deal with several streams in the northeast
San Bernardino area issuing from-mountain canyons to the north. Flood
waters and debris debouche onto an urban area, and flow southwest into
Warm Creek and into the Santa Ana River. Survey report studies under
separate authority are due for completion in .1974.
-19-
In the Riverside area, the headwaters of University Wash originate near
the University of California at Riverside. The stream flows northwest-
ward toward the interchange of the Riverside freeway and route 60 freeway.
Farther west, the stream is joined by Spring Brook Wash coming down from
the northeast. The streams discharge into the Santa Ana River in the
vicinity of Lake Evans in Riverside. The 1969 floods damaged about 40
homes, 10 business establishments, an elementary school, and closed
several arterials. Total damage was about $370,000. Channel improvements
on these streams are authorized and general design studies have been
initiated.
What is the Best Project, or What Would Be a Good Project?
The Decision Process - We recognize that a number of criteria enter into
the collective judgments of many people in three counties plus others as
to what constitutes a good overall plan of improvement for. the Santa Ana.
River Basin.
A diversity of views is currently being expressed regarding the desirability
of various structural measures to provide flood control along the lower
portion of the Santa Ana River:
a. Upstream flood control districts and the City of Corona have
expressed apprehension over the large amount of land that would be required
for enlargement of Prado Reservoir and, accordingly, lost from the tax
rolls. In addition, the possible displacement of many dairies that have
recently located in the Chino area has further aroused public sentiment.
In the past 12 months, about 200 homes have been built at the edge of
existing Prado Reservoir, in the area where reservoir expansion is being
considered. Many horses are kept at these tracts, as this is a popular
area for horseback riding.
b. Concern has been expressed that if Prado Dam is enlarged, the
commitment of Federal funds would reduce funds available for the timely
construction of needed flood control projects in the upstream portions of
the Santa Ana River drainage basin. Flood damages could be greatly
reduced by improvements along San Timoteo Creek in Redlands, Wilson Creek
in the Dunlap Acres area of Yucaipa, and a Zanja ditch passing through
downtown Redlands, all in San Bernardino County. In Riverside, the area
indicating the greatest potential for relief of damages is along Temescal
Wash in east and north Corona. Another area subject to damage lies in west
Corona in the vicinity of West 6th Street and Lincoln Avenue. All of
these areas were severely damaged during the floods of 1969.
c. Some upstream interests feel that a better basin environment would
be attained if a large reservoir with open space and recreational use is
developed. A larger Prado Reservoir area would allow more kinds of
recreational use and would form a greenbelt buffer zone from the adjacent
urbanizing sprawl.
-20-
d. Orange County definitely prefers a minimum release from Prado
Reservoir. Orange County has in recent years designed and constructed
its facilities along the Santa Ana River for flood control, water conserva-
tion, recreational and open space amenities on the basis of the 20,000
cubic feet per second release, from Prado Dam. Orange County is of the
view that a greatly widened channel would cause serious problems with homes
displaced, utilities relocated, bridges rebuilt, and the raising of funds
to pay for the requirements of local interests for a Federal project.
The strip of land within 500 feet or so of the existing river channel is
rapidly filling in with homes, luxury apartments, mobile homes, and
industrial plants.
e. Some increase in flow capacity of the river without the taking
of homes could be accomplished by deepening the channel about 4 feet, or
raising the levees an equivalent amount, and rebuilding about 26,bridges.
However, long strips of smooth, deep, and wide concrete channel do not
appeal to numerous people who wish to see a wide, grassy, green recrea-
tional area throughout the river strip. The wide greenbelt area serving
as floodway certainly has many esthetically appealing aspects, but it
would require about twice the width to carry the same amount of floodwater.
f. People in the 10-mile long Santa Ana Canyon area, from Prado Dam
to Imperial Highway, object to releases from Prado, even as low as 5,000
cubic feet per second, because of damages to two golf courses, a park, and
damage resulting from land erosion in orange groves alongside the river.
g. Downstream interests desire that the ground-water recharge perco-
lation basins along the Santa Ana River continue to operate effectively;
and that the natural habitat, particularly that in the Santa Ana Canyon,
be preserved and enhanced.
Thus far, we find no consensus of opinion. In order that our studies on
river basin improvements might be responsive to the needs of many people,
members of our staff have attended several open meetings to exchange
views, including discussions on 12 June 1970 at Corona and 9 February 1971
at Corona; 17 March 1971 at Ontario;- 22 Jun? 1971 at Ontario; 17 November
1971 at Fountain Valley; 15 December 1971 at Orange County Water District
office in Santa Ana; 21 December 1971 with the City Council, City of Anaheim;
13 April 1972 with an environmental work group at Corona; 12 May 1972 in
Anaheim; 10 August 1972 in Anaheim; 12 October 1972 in Riverside; 7
December 1972 in Riverside; 13 February 1973 in Yorba Linda; and 22 February
1973 in Huntington Beach; 1 March 1973 at Anaheim, and25 April 1973 in
Redlands. The most recent meeting is that with officials of counties of
Orange, Riverside, and San Bernardino held in the City of Riverside on
11 May 1973.
-21-
The major effort in developing a recommendation for a plan of improvement,
as seen right now, is in working to find some agreement among responsible
people in the three counties of Orange,. Riverside, and San Bernardino.
The object is to develop a package that is reasonably acceptable to all
of the communities and people concerned. We are faced not only with the
problem of determining which properties are to be taken for Prado Reservoir
and/or lower Santa Ana River channel expansion, but we must recognize the
problem of local capability in cost-sharing for the plan selected. The
costs to Orange County, for instance, for relocations and additional rights-
of-way are estimated to range from 33 million dollars in the case of a large
reservoir and channel to more than 200 million dollars for a 200,000 c.f.s.
channel. Orange County, in considering its ability and willingness to finance
their share of costs, must also consider the needs for other local flood
control works.
The State of California Department of Water Resources has been working with
the Los Angeles District in developing coordinated input from local interests
regarding multipurpose considerations compatible with the improvement of
Prado Basin and the lower part of the Santa An River. They have prepared
one report dealing with flood control, water conservation, water quality,
recreational improvements, fish and wildlife, and environmental impacts.
Another report is scheduled for completion in June 1973.
The next principal activity in the development of basin plans of improvement
acceptable to people in the three counties is more work group and informal
public meetings similar to those previously described. These meetings,
probably during June, July, and August 1973, will be in locations such as
Redlands, Loma Linda, Yucaipa, and Corona. Discussions will be mostly con-
cerning improvements along Wilson Creek in Yucaipa, a creek that passes
through downtown Redlands, Mill Creek levee improvements east of Redlands,
the Santa Ana River dam near Mentone, San Timoteo Creek at Loma Linda,
Temescal Wash and Prado Reservoir modifications at Corona. The upstream
works are important to the people living in those flood hazard areas in a
similar way that improvements on Prado Reservoir, lower Santa River and
Santiago Creek are important to flood-hazard-area residents in Orange County.
Through the involvement of all concerned people, we hope to achieve a
consensus on the most desirable plan for further study. After such consensus
is developed, further studies will culminate in a recommended plan to be
presented in a survey report which is scheduled to be completed in 1974.
The report would have to be reviewed by Federal and other agencies prior
to submittal to Congress.
-22-
SUMMARY
ALT. SFF DAMAyES ACRES 9ZELOCATIONS COSTS (4M I LLION)
PREVENTED6973) MEAL ESTATE 140MES - 5XIDGES FED LOCAL. TOTAL
I 0 0 0 0 O 0 0
Z 0 19 O 0 31 0 31
3 2.215illion 7, 730 710 13 256 37 293
4 2.2 Billion 4,,39 0 C050 25 Z55 52 287
J5 21 E511IiOn 51430 900 33 220 73 293
ro 2.(0 3illion 7 ,090 340 13 331 37 374
`7 2.613illion 51590 350 25 302 52 554
8 2.(o 1511 I i on 41250 (070 33 2 S I 73 354
9 4 2.2 C3 i l l i 0 n 30 210 28C000 35 172 221 39 9
10 4 Z.2 3illiort 5,040 71200 35 14 ro 535 &81
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