HomeMy WebLinkAbout042793 CC/Murrieta Jnt. AgendaAGENDA
TEMECULA CITY COUNCIL
A SPECIAL JOINT MEETING WITH THE
CITY COUNCIL OF THE CITY OF MURRIETA
TEMECULA COMMUNITY CENTER, 28816 PUJOL STREET
APRIL 27, 1993 - 6:00 PM
CALL TO ORDER:
Invocation
Flag Salute
ROLL CALL:
Mayor J. Sal Mufioz, City of Temecula
Father Ed Renner, St. Thomas Episcopal Church
County Supervisor Bob Buster
COUNCILMEMBERS: Birdsall, Parks, Roberts, Stone, Mufioz
COUNCILMEMBERS: Allen, Smith, Welsh, VanHaaster, Peery
PRESENTATIONS/
PROCLAMATIONS
PUBLIC COMMENTS
Presentation to City of Temecula - Ralph Love Family
Proclamation - Ralph Love Day
A total of 15 minutes iS provided so members of the public can address the Council
on items that are not listed on the Agenda. Speakers are limited to two (2) minutes
each. If you desire to speak to the Council about an item not listed on the Agenda,
a pink 'Request To Speak" form should be filled out and filed with the City Clerk.
When you are called to speak, please come forward and state your name and address.
For all other agenda items a "Request To Speak' form must be filed with the City Clerk
before the Council gets to that item. There is a five (5) minute time limit for individual
speakers.
NEW BUSINESS
Presentations by U.R.G.E. and the Riverside County Flood Control District
Channelization Ootion for the Murrieta Creek
RECOMMENDATION:
1.1
Receive testimony from the Union for River Greenbelt Environment and
from the Riverside County Flood Control District on plans for flood
control protection of the Murrieta Creek.
1.2
City Councils provide appropriate staff direction.
V:/jereeldegende/O427e3 1 04113/93
CITY MANAGERS REPORTS
CITY ATTORNEY REPORTS
CITY COUNCIL REPORTS
ADJOURNMENT
City of Temecula - Adjourn to a meeting, May 4, 1993 at the Temecula Community Center
28816 Pujol Street, for the purpose of holding a Public Hearing on remaining elements of the
General Plan.
City of Murrieta - Adjourn to a regular meeting, May 4, 1993 in City Council Chambers,
Murrieta City Hall, 26442 Beckman Court, Murriete, California.
V'J'lgreeJaeef~iN042183
0411
ITEM
1
RIVERSIDE COUNTY FLOOD CONTROL
AND WATER CONSERVATION DISTRICT
EXEC'UTIVE
MURRIETA
for
SUMMARY
the
CREEK. FLOOD CONTROL
PROJECT
Riverside County, California
March 22. lgg3
KENNETH L. EDWARD9
(~enerll Manager-Chief Engineer
TABLE OF CONTENTS
Paue
PROJECT INTRODUCTION .................. 1
SUMMARY OF FINDINGS .................... 1
Project Need '
Project Objective ·
Public Participation ·
Availability of Practicable Alternatives ...... 5
Recommended Project ................. 5
Mitigation Measures to Reduce Impacts
of the Recommended Project ............ 7
STORMS OF 1993 ..................... 8
SECTION 404 APPLICATION ................. 9
Figure
1-1
1-2
1-3
1-4
2-1
3-1
3-2
T,TST OF FTGURRS
Vicinity Map
Project Location Map
100 Year Flood Plain Map
Aerial View
Summary of Alternatives
Mitigated Trapezoidal Channel
Rectangular Concrete Channel
-i-
)(I~I~T ILNZ't. ~'RRI~X FT.OOD C~O]I'ZfROT. p:lt, Ck3'l~-z,
PROJECT TNTRODUCTTON
The Riverside County Flood Control and. Water Conservation
District (District) is proposing to improve approximately 11
miles of Murrieta Creek to provide 100 year flood protection to
existing development. The Murrieta Creek flood plain includes
portions of the Cities'of Murrieta and Temecula, and..the
unincorporated community of Wildomar, all located in southwestern
Riverside County, California. The project vicinity and location.
are shown' on Figures 1-1 and 1-2. The 100 year flood plain
limits are shown on Figure 1-3, and an aerial view looking
southeasterly down Murrieta Creek toward Temecula (from-Fig
Street 'in Murrieta) is shown' on Figure 1-4.
SUmMaRY OF FTNDINGS
Protect Need - The Murrieta Creek flood plain impacts the Cities
of Murrieta and Temecula, and the unincorporated community of
Wildomar, which are clustered along a corridor paralleling
Murrieta Creek. The 100 year flood plain covers 2,504 acres
which have been developed for.many years, initially as farms and
ranches, and more recently for residential, commercial and
industrial uses. The value of property subject to damage within
the flood plain is estimated to be in excess of six hundred
million dollars, and includes agricultural, residential,
commercial and industrial property as well as public
infrastructure.
- I -
Over the past 10 years population in the w~tershed has increased
dramatically, and flooding problems have been magnified to the
point where even moderate storm events threaten public health and
safety. In the City of Temecula most of Murrieta Creek is not in
public ownership, and thus is not routinely maintained. Growth
of vegetation, fed by urban drainage, has seriously.obstructed
this.reach of the s~ream. Reduced velocity of flow due to the
vegetation has accelerated deposition of sediment in this area
further reducing flow capacity through the old townsite of
Temecula. The District estimates that over the past 12 years the
capacity of Murrieta Creek through downtown Temecula has been cut
roughly in half by these factors.
The banks of Murrieta Creek are highly erodible~ and due to the
obstructed condition of the channel flows tend to attack the
banks threatening adjacent development. During the floods of
1980 severe bank erosion in Temecula undermined structures on a
lumberyard and threatened other commercial properties. During
the relatively minor storms of February 1992 bank erosion exposed
leach fields and septic tanks serving private residences on the
banksof Murrieta Creek near Kalmia Street, allowing raw sewage
to discharge to the Creek. Emergency measures by the District
were required to restore the banks and prevent further
contamination of the Creek.
Traffic in the City of Murrieta is seriously disrupted during
storm events. During one of the storms of February and March
1991, an elderly woman in her car was washed off Jefferson Avenue
- 2 -
by storm flows from the Ealmia Street tributary, and had to be
rescued by the Fire Department. During the relatively minor
events of February 1992, the City of Murrieta was dissected by
closure of major. transportation corridors at 15 separate
locations. Similar problems occurred in the City of Temecula
with closure of Front Street, and in the Wildomar area with the
closure of McVicar'Street. Fortunately, there was no loss of
life in these events, but future tragedies are certain in greater
storms unless remedial action is taken immediately.
Project Objective - The primary objective of the proposed project
is to protect existing private development and public
infrastructure, provide for acceptance of lateral drainage,
provide all weather access, and eliminate an ongoing threat to
public health and safety by implementation of a project to
provide 100 year flood protection along Murrieta Creek. A number
of secondary benefits will also accrue from the Recommended
Project. Specifically, the project will also:
Facilitate bridge .crosSings of Murri'eta Creek, allowing
access during flood emergencies. Storm events now leave
many citizens completely isolated from emergency
services.
Provide an outlet for major tributary streams and local
drainage facilities.
Provide an open space corridor through the communities in
- 3 -
concert with, and in fact as the basis for, the Murrieta
Creek element of the proposed Multiple Species Habitat
Conservation Plan of Riverside County.
Provide for Joint use of project rights of way for a
continuous 11 mile long trail system including'hiking,
biking and equestrian uses, and a link to future park"
sites.
Enhance groundwater recharge by providing a wider unlined
channel invert.
Provide a continuous' habitat corridor over the.ll mile
length of the project.
Public Participation - A broad based committee of local citizens
was appointed by the Riverside County Board of Supervisors in the
Fall of 1989 to provide local input; to aid in evaluation of
alternatives, and to recommend a consensus project which would
provide 100 year flood prot~ction"for Murrieta Creek. The
Murrieta Creek Citizens, Advisory Committee (MCCAC) held
seventeen public meetings to provide direction to District staff,
review progress, and provide a forum for public input. The
Committee actively participated in selection of alternatives for
evaluation, and has endorsed the recommended project.
In addition, District staff has met with numerous public interest
groups and their consultants regarding the proposed project, and
- 4 -
presentations were made at City Council meetings in Murrieta and
Temecula. Two Section 404 pre-application conferences were also
held with U. S. Army Corps of Engineers Regulatory Branch staff.
Availab~]ity of Practicable Alternat{ves - Ten candidate
alternatives were screened with respect to their ability to meet
the project objectives. Only two alternatives, the'Mitigated
Channel which is the recommended project, and the Master Plan
Channel were found to be practicable. A summary of all
alternatives investigated and their estimated costs is shown on
· Figure 2-1. Offstream alternatives were not investigated since
the project is water dependant.
Recommended Pro~ect - The Recommended Project is the Mitigated
Channel alternative which was determined to be the least damaging
practicable alternative. It would improve just over 10 miles of
Murrieta Creek using the typical section shown on Figure 3-1.
The channel bottom would remain unlined to facilitate groundwater
recharge, and to allow for vegetative growth. Instead of
armoring the slopes with concrete lining for erosion protection
as 'is traditionally done, either. an articulated mat of concrete
blocks with open cells or ungrouted rock riprap would be used.
The open cells or voids in the erosion protection system would be
backfilled with soil and hydroseeded with appropriate native
vegetation. Mitigation of riparian habitat would be accomplished
by incorporation of two 50-foot riparian habitat strips within
the channel bottom at the toe of each sideslope. The habitat
strip would be planted with typical riparian vegetation including
- 5 -
Cottonwoods and Willows. The riparian habitat strip would not be
routinely maintained, and would remain undisturbed after
planting. Non-woody and/or wetland type vegetation would be
allowed to grow in the unlined channel bottom between the habitat
strips, but since this part of the channel is required for flow
conveyance it would be maintained annually by mowing with large
tractor drawn rotary mowers. '
Downstream of Rancho California Road in Temecula, development has
encroached upon the stream banks to the extent.that the mitigated
trapezoidal channel would not physically fit. For this reach a
fully lined rectanqular channel would be required over a length
of about 4000 feet. The rectanqular concrete channel section is
shown on Figure 3-2. Riparian/wetlands impacts in this reach
would be mitigated by allowing non-woody, wetlands vegetation to
grow on the bottom. Visual impacts of the vertical walls could
be mitigated by use of colored concrete, textured forms, clinging
vines grown down the face of 'the walls and decorative "wrought
iron" type fencing. Alternatively, the channel could simply be
screened by landscaping..
The Recommended Project has an estimated construction cost of
$59.9 million. It provides a viable means of eliminating the
threat of loss of life and property due to flooding.with no net
loss of wetlands or riparian habitat. It will facilitate
bridging of the Creek allowing access to those now cutoff from
emergency services during even moderate flood events, and
facilitate local drainage. It will also provide a wide, unlined
- 6 -
channel section improving groundwater recharge, provide an open
space riparian corridor, allow bike and pedestrian trail use on
the access roads which could link future park sites, and allow
equestrian trail use in the channel bottom.
Mit~aat~on Measures to Reduce T~D~CtS ofthe Recommended
Pro~ect - The Recommended Project,' which is the Mitigated Channel
alternative, avoids the most valued aquatic areas upstream of the
Temecula Creek/Murrieta Creek confidence, and provides in kind
onsite mitigation for all impacted aquatic values. The
Recommended Project provides 144.1 acres of in kind onsite
replacement for lost wetlands with low growing vegetation (2.5:1
ratio),. and provides 128.1 acres of in kind onsite replacement
for lost wetlands with woody vegetation (2.5:1 ratio). In
addition, the Recommended Project provides a continuous riparian
habitat corridor between Rancho California Road and the end of
the project upstream of Clinton Keith Road, a length of about 9.3
miles. Currently, with the exception of the short reach
downstream of Winchester Road, only sparse and intermittent
vegetation exists in this reach.
Mitigation planting would be based on detailed landscape and
irrigation plans prepared in conjunction with the final design
process, and subject to approval by the U. S. Army Corps of
Engineers and California Department of Fish and Game. Mitigation
planrings would be monitored for 5 years in accordance with a
detailed plan subject to approval by the same agencies to ensure
success of the re-vegetation plan.
-- 7 -
STORMS OF 1993
Since this report was originally completed in September of 1992,
Riverside County was hit with devastating storms in January and
February of 1993, resulting in a Presidential Disaster
Proclamation. Hardest hit was the southwest region of the County
where six lives were lost in mid-January.
Nearly continuous rainfall saturated the region over the first
half of January, with 15 day rainfall totals having return
periods of 100 to 1000 years over the Murrieta Creek Watershed.
This was followed by high intensity rainfall on the afternoon of
January 16, reaching a maximum of 4.4 inches in six hours over
the Santa Rosa Plateau. This intense rainfall falling on the
already saturated watershed, caused rapid increases in runoff
rates and wide spread flooding along Murrieta Creek and its
tributaries. The historic Old. Town .section of Temecula suffered
the most serious flooding when overbank flows of 3 feet and more
raged through private property and City streets. The U. Sj
Geological Survey has issued a provisional estimate of 28,800 cfs
for the peak discharge on Murrieta 'Creek at Temecula.
District costs for emergency flood fighting, and City of Temecula
costs for partial restoration of Murrieta Creek, have already
exceeded $650,000, and as much as an additional $650,000 of.work
may be required to complete restoration of District facilities.
In addition, private interests are expending an estimated
$950,000 on restoration of certain non-public reaches of Murrieta
Creek, and the Cities of Murrieta and Temecula face in excess of
- 8 -
$1,000,000 in major restoration costs for damaged road crossings,
bridges and utilities. 'Estimates of damage to private property
are not firm at this time, but based on currently available
information will probably exceed $4,000,000.
S~-CTTON 404 APPtlCATTON
~he District filed a Section 404 Permit Application for the
proposed Murrieta Creek Flood Control Project with the Los
Angeles District of the U. S. Army Corps of Engineers in
September of 1992. The submittal consisted of six separate
volumes and included detailed reports on Wetlands Delineation~
StePhenst Kangaroo Rat Survey, Archaeological Survey, Conceptual
Mitigation Plans, Section 404 (b)(1) Alternative Analysis, and
Preliminary Project Plans. A Public Notice was issued by the
Corps in February 1993. The public comment period was originally
to close on March 11, 1993, but has been extended to April 10,
1993. The Section 404 Permit Application materials are available
for review at both the Murrieta and Temecula City Halls (Public
Works Counter), and the DistriCtts office. ·
Upon receipt of a 404 Permit, the District plans to move forward
with completion of detailed construction and landscape plans, and
to pursue funding opportunities for this critical project.
- 9 -
L.A. )~ ~'-_$-15 SN_A3ERNARDINO
\ COUNTY $-215 COUNTY
F5 60 ' .S BERNARDINO
LOS "' I / 91 VERSIDE, L60 '
SANTA CATALINA t,~, ) TEMECULA
LAND , / VALLEY
I ~ PROJECT
,b,~ C' I-5 VICINITY
0
SAN CLEMENTE
ISLAND
SAN DIEGO
COUNTY
SAN DIEGO
FIGURE 1-1
VICINITY
MAP
OJf ~
IA.11'110 i
0
0
fi
AA I
g~ , ~p~rN31 ~
x
FIGURE
M U lI( R I E T A
CR. EEK
Channelization
Alternatives:
COST
- Hi t i gated Channe 1
(Recommended Pro;j'ect )
- Master P 1 an Channe 1
- Parkway Channel
F~ll/Levee Alternatives:
$S9,938,000.
$27,941,000
$120,000,000+
- Fill of Flood Plain
- Levees
Bypass Alternatives:
$148,301,000
$83,908,000
- Mitigated Channel
with Tunnel Bypass
- M~t~gated Channel
with Concrete Boxes
$127,847,000
$168,648,000
Storage
No Project
Alternatives:
Re9 i ona 1 . Dams
Ons ite Retent i on
A1 ternat i ve
$112,130,000
$346,943,000
FIG. 2-1 i~I URRIETA
CREEK
ALTERNATIX'ES
0
n
n
/i,i
z _z
i,i
7 I.iJ
!"'C){J
i3::._lZ
i'iC) C)
W
W
W
W
W
April 9, 1993
To:
U.S. Army Corps of Engineers
California Department of Fish and Game
Resource Agencies
From: Union for a River Greenbelt Environmgnt (URGE)
P.O. Box 890892
Temecula, CA 92589
Subject:
404 Permit and 1601 Notification for the Murrieta Creek Flood Conuol Channel (92-72a-
RS)
The attached material is sent in response to the public comment period for the Riverside County Flood
Control District's proposal to channelize Mttrrieta Creek
URGE supports the need for flood control of Murrieta Creek. We are concerned however that the
proposal by the RCFCD results in significant long term irreversible impacts to the environment, both
natural and human, which are avoidable or which can be mitigated to below a level of significance.
The commitment of the RCFCD to mitigate impacts to both the natural and human environment is
seriously questioned. Quoting from the minutes of the July 26, 1990 meeting of the Citizens Advisory
Committee, included in the 404 permit application package (Alternatives Analysis, Appendix A), a
RCFCD Zone 7 Commissioner: "Joseph Phelps argued that the mitigation would wash away in a flood
and is only being proposed to obtain the 404 permiL"
URGE's goal is not to prevent the provision of flood control for the residents of Temecula and Murfieta,
but to provide flood protection with the minimum impacts 'to the natural and human environment. URGE
believes that by submitting a proposal which meets the objectives of the resource agencies, avoids public
safety impacts and enhances the human environment that it is possible to achieve a more rapid approval
of the required permits.
With this in mind, URGE submits its alternatives to the RCFCD plan. These alternatives were developed
by adding mitigation to the RCFCD proposal to avoid or mitigate impacts to the natural and human
environment. Biological mitigation included in the URGE proposals was developed without consultation
with the resource agencies and thus will certainly need modification prior to implementation. URGE feels
that these alternatives are technically feasible, financially feasible and environmentally superior to
the proposal of the RCFCD. URGE would ask that a 404 permit be granted based upon one of the
URGE alternatives. _
;JRGE
;
Sincerely,
Willie Gale
Chairperson, URGE
U.R.G.E.'s
THREE ALTERNATIVES
URGE Alternative 1
U.R.G .E.
Project Alternatives
Urge Alternative 1 would improve 10.25 miles of the 11 mile Murrieta Creek using the typical section
shown in Figure 1. This alternative would proviAe flood control for the 100 year storm and facilitate
local drainage as well as provide an ou~et for tributary flows.
URGE Alternative 1 incorporates a parkway channel with channel right-of-way widths varying from 360
to 590 feet. (See Table 1) The parkway channel would be a grass lined channel incorporating variable
side slopes. Side slopes would range from 4/1 (horizontal to vertical) to 12/1.(see Figure 1) Side slopes
would be contoured to simulate natural terrain. The erossectional area of this channel would be
sufficient to carry the design storm (Qi0o) of 38,500 CFS (cubic feet per second). Velocities would be
limited to 5 feet per second throughout the channel except in the "Old Town" Temecula section where
velocities would be 12 FPS. The channel would utilize RCFCD aligmnent and depth. There are existing
sections of the project, particularly in Temecula, which have substantial encroachments. In these
sections, the right of way would be reduced to the extent necessary to avoid acquisition of costly
structures. In the areas where the right of way is constrained, the channel would reduced in width the
minimum amount which would be absolutely essential. Side slopes would be steepened the minimum
amount necessary to permit passage of the design flow. Erosion protection for the channel would be
required in areas with steeper side slopes and velocities over 7 FPS. Fabric mats would be utilized for
slope protection where feasible. If side slopes must exceed 4/1, non invasive ground covers would be
u'ulized for slope cover.
Ponding areas would be excavated in the channel. These ponding areas would be a minimum of one
quarter acre each and would provide watering holes for wildlife. These ponding areas would be placed
at intervals of less than one mile. Nesting areas for the Southwestern Pond Turtle would be provided
adjacent to the channel outside the 100 year flood plain. These nesting areas would 'be a minimum of
600 deep and 600 feet wide. Nesting areas would be hard packed clay with a costal sage scrub covering.
Where possible, nesting areas will be established with south facing slopes. These nesting areas would
not be provided in the substantially built up commercial and industrial areas.
The channel would include a 50 foot wide low flow channel which would be developed as a habitat
corridor. This habitat could be widened by slight increases in average sideslope. Channel bottoms and
sides within 100 feet of the habitat corridor would be planted with native grasses. Areas between the
ponding areas and nesting areas will be planted with native grasses and costal sage scrub elements. The
remainder of the channel bottom and channel side slopes would be planted with native grasses or non-
invasivc exotic materials. Native grassland areas would be maintained with an annual mowing only.
Trees would be removed from the native grasslands.
Velocity within the channel would ~e conlroHed through the use of landform and vegetation. Energy
dissipators would be placed as required at the confiuence of tributaries to reduce incoming velocity and
to provide a controlled location to precipitate silt. Weftands areas would be established in these locations
to f~ter pollutants from low flow.
The habitat corridor, nesting areas and native grasslands woUld be limited to passive recreation. This
Rmmd: 4/911993 ]
U.R.G.E.
Project Alternatives
would maintain a minimum 100 foot buffer between primary habitat areas and corridors and active
recreational use. Given the narrowness of the channel bottom, them would be few opportunities for
active recreational use. Primary pathways would be located at the top of side slopes and would be
meandering pathways 12 feet in width. They would be designed primarily as pathways but would be
designed to provide access for flood watch and maintenance. A permanent irrigation system is proposed
for turf grass areas. Supplemental irrigation will be provided, ff necessary, for the native grasslands,
riparian and nesting areas until they ~an be fully established and weaned from supplemental water.
The channel width for the "Old Town" Temecula segment is proposed to be increased by 40 feet This
would be accomplished by reducing the service road width from 220 feet to 12 feet where required to
accommodate the increased channel width without impacting existing development With velocity
reduced from the RCFCD proposal of 17 FPS to 12 FPS, substantial design alternatives for the "Old
Town" section including changes in materials would be possible. Slick concrete would no longer be
necessary. Wrought iron or similar decorative fencing is proposed through the "Old Town" segment as
a result of the high velocities. Access roads through the "old Town area would be constructed of
decorative paving materials. The use of the concrete floater slab may no longer be necessary because
of the reduction in velocity.
General:
Total land acquisition would require 90 acres more land than the RCFCD proposal for channel and right
of way plus 70 acres for Southwestern Pond Turtle nesting areas. Biological monitoring would be
provided for a minimum of five years after installation of plant materials.
This alternative has an cstimatecl cost of 45.9 Million dollars including right of way acquisition and
additional lands for Southwestern Pond Tunic nesting areas. (See Table 2)
MITIGATION MEASURES INCORPORATED IN CHANNEL DESIGN:
Erosion:
The design velocity of 5 FPS will substantial reduce erosivencss of the water. The planting of native
and turf grasses to provide a uniform ground cover will also help to control erosion. The use of energy
dissipating devices at the enlrance of tributary flow will reduce erosion. The use of relatively fiat side
slopes, average 8/1 will reduce the effects of erosion.
Siltation:
The reduction of erosion within the'channel will substantially reduce the siltation problems within the
channel. The use of energy dissipators at tributary entrances will deposit silt in controlled locations.
The maintenance of velocities of 5 FPS would significantly reduce the silt carrying capability of flood
flows.
Water Quality:
2
U .R.G .E.
Project Alternatives
The use of weftads to ~ter pollutants will improve water quality. The reduced erosion and siltation
will also improve water quality. The capability of additional groundwater recharge as a result of project
design will also reduce the degradation of groundwater sources.
Groundwater Recharge:
The proposed channel will provide approximately 370 acres more wetted area for recharge than the
RCFCD mitigated channel. With velocities 1/'2 to 2f3 those of the RCFCD proposal more groundwater
recharge possibilities exist.
Riparian Habitat:
The project will disturb approximately 60 acres of riparian habitat This alternative will provide
approximately 70 acres of riparian habitat within the habitat corridor. While this is only 1/'2 of the
amount proposed in the RCFCD plan, URGE feels that the quality of the overall habitat environment
is far superior to that proposed by RCFCD. Reduced velocity and reduced siltation will result in less
impact to the riparian habitat. As a result of the reduced silta~on, it will not be necessary to periodically
remove and replant the habitat thus allowing a more mature development of the habitat. The value of
two separate strips of habitat as proposed by RC~CD would b~ only marginally better under optimum
conditions.
Wetlands:
This proposal would impact approximately 60 acres of wedands. The low flow channel will provide
approximately 70 acres of weftands. Additionally, wetlands areas arc proposed at each tributary
entrance. The 100 foot native grasslands buffers on either side of the low flow channel will allow the
rcdcvclopmcnt of wetlands where the hydrologic regime will permit. Given the opportunity to develop,
those areas which were previously wc~ands will return as wetlands. Wetlands will be less subject to
impact as a result of lower velocity and less siltation.
Southwestern Pond Turtle:
This Category 1 candidate for Federal lisling is known to inhabit Muftieta Cr~k. A shell was identified
during the wetlands delineation. The inclusion of pondlng areas within the channel, at intervals of less
than one rnilc, will provide additional habitat opportunities. The relatively flat ( average 8/1 H/V ) will
allow unresWicted movement from habitat areas in the creek to nesting areas outside the creek. Nesting
areas would be provided outside the 100 year flood elevation. These nesting areas are proposed to be
six hundred feet wide and six hundred feet deep. This will equal nearly one half the maximran normal
travel distance for this species. Nefdng areas would provide a hard packed chy surface with a costal
sage covering and would provide south facing slopes. Channel areas between the low flow channel and
nesting areas would be native grasshnds with elements of the costal sage scrub community. Velocity
proposed by the RCFCD exceeds that acceptable for the Southwestern Pond Tunic. Proposed velocities
of 5 FPS for this alternative are consistent with the habitat requixements for the species.
Least Bei!'s Vireo:
U.R.G .E.
Project Alternatives
The provision of the ripaxian habitat corridor will some assistance in migration. Habitat areas provided
are expected to be too small to provide viable nesting areas. The overall namralness of the channel
compared to the RCFCD will assist in its viability for its use by the Least BeH's Vireo.
California Gnatcatcher:
The project is only expected to disrupt 3.36 acres of costal sage scrub habitat. The project will create
or preserve .approximately 70 acres of costal sage scrub habitat for the Southwestern Pond Turtle nesting
areas. Individual nesting areas for the turtle will be less than 10 acres each and are thus not expected
to provide beneficial habitaL The placement of these areas adjacent to the habitat corridor along with
the more natural appearing channel development will improve the viability of its use by the Gnatcatcher.
Animal Migration:
The 50 foot riparian habitat corridor in conjunction with the 100 foot native grassland biers on either
side will provide a continuous north south habitat corridor for animal migration. This corridor will be
enhanced by the use of the ponding areas which will serve as watering areas. The viability of the habitat
corridor will be enhanced by the creation of the Southwestern Pond Turtle nesting areas outside the 100
year flood plain but contiguous with the habitat corridor. As a result of the reduced velocity, 5 FPS,
reduced erosion and siltation, there will be less impact on the habitat corridor from flood events thus
permitting a more mature development of the habitat The reduction of the side slopes from 2/1 as
proposed by RCFCD will permit unrestricted wildlife movement east west across the creek. The reduced
side slopes will permit the movement of the Southwestern Pond turtle from the habitat area to nesting
areas. Since reduced velocity reduces the public safety hazard, fencing will not be required thus
removing that potential barrier to wildlife movement. The more natural overall appearance of the
channel will make the habitat corridor more viable.
Downstream Habitat:
While peak flows will remain the same under this alternative as. the RCFCD plan, the exit velocity from
the *'Old Town Segment will be reduced from 17 FPS to 12 FPS. Velocity would be decreased even
more south of Main SixeeL Reduced velocity combined with a reduced silt load would reduce but not
eliminate downstream habitat desixuction.
Local Flooding:
The channel design for this alternative would provide the same level of flood protection as in the
RCFCD plan. In the event of a flood event in excess of the 100 year event damage might be reduced
somewhat as a result of reduced velocity.
Downstream Flooding:
Downstream flooding impacts would be the same as those in the RCFCD plan.
Rmeiml: 4/911993
Visual Resources:
U.R.G .E.
Project Alternatives
The reduction of side slopes from a 2/1 side slope as proposed by RCFCD to an average of 8/1 will
reduce the visual impact by the elimination of the obvious manmade 2/1 slopes. Additionally, the side
slopes will utilize variable slopes designed to simulate natural terrain. Berms or moguls utiliTed in part
to control velocity will also break the straight line appearance. The elimination of the armoffiex and
its attendant problems or erosion of the soil covering will also reduce the visual impact of the project.
As a result of the elimination of fencing throughout most of the length of the project, another discordant
element is removed. The provision of 100% planting for the channel will provide a more uniform
appearance. A neater appearance wffi be maintained as a result of less erosion and siltation. Within the
"Old Town" Temecula section, reduced velocities will provide a much greater choice of architectural
treatment for the channel. Decorative paving in the "Old Town" section would transform the normally
negative influence of an unpaved access road into a "promenade" which could serve as an enhancement
to local businesses.
Land Use:
Mitigation for land use impacts within the channel design include those measures discussed in the public
safety and visual resource discussions. These measures will make the channel more compatible with all
land uses. The greenbelt approach embodied in this alternative is more compatible with the Draft Land
Use Plan policies and map for the City of Murrieta.
Public Safety:
The primary public safety impacts created by the RCFCD are as a result of the steep side slopes and
high velocity of flow in the channel. The mount of force exerted on a body by water flowing at 3
MPH is thirty-five pounds. At 6 MPH this force increases to 140 pounds. At 12 miles per hour this
increases to 540 pounds. This alternative has eliminated these impacts through the use of relatively fiat
, average 8/1, side slopes and a reduction in design velocity w 5 FPS. The channel design will also
allow a gradual decrease in velocity as you near the outside of the channel thus allowing someone
trapped w swim toward the outside where force is reduced even more. Once reaching the outside it will
be possible to climb out of the channel.
Recreational Use:
The project design incorporates two multi use trails at the top of the slope. The channel design, because
of its fiat side slopes will accommodate additional trails. The project will provide 140 acres of lands
for habitat use which will be genenllly be unavailable for use. There will be approximately 200 acres
of native grasslands which could be utilized for low impact passive use. One hundred sixty acres of land
would b~ available for active recreational use. Areas would generally be small enough to provide space
only for playgrounds, volleyball or basketball use. There would not be sufficient width for activities
such as soccer, softball or football. There will be two trails for the full length of the project.
For a summary of alternative impacts see Table 3.
Rt. vim!: 4/911993
5
URGE Alternative 2
U.R.G.E.
Project Alternatives
URGE Alternative 2 incorporates a parkway channel with channel fight-of-way widths vm3ring from 360
to 590 feet (See Table 1) This channel would be the same as the channel for URGE Alternative 1
except as mod_ified below. While the channel would still be designed to carry a peak flow of 38,500
CFS, the 100 year flood flow would be reduced to approximately 29,000 CFS. The channel would be
capable of handling flows approximately 9,000 CFS greater than 100 year flows.
Swrm water detention:
Alternative 2 incorporates a mud of 5,000 acre feet of storm water detention. It is proposed that there
be five detention areas, each with a nominal size of 40 acres. These detention areas would be located
primarily within the existing 100 year flood plain approximately 100 feet from the creek. The area
between the detention basin and the creek would be planted with costal sage scrub species. Side slopes
of the detention areas would also be planted using typical costal sage scrub materials. Each detention
area would be excavated to an average depth of 25 feel Location at the confiuence of tributaries would
maximize potential benefit. Marsh areas would be incorporated in the low flow channels of the detention
basins to capture the first flush and remove polhtants. It is proposed that two areas, for a wtal acreage
of 80 acres be devoted to the establishment of riparian habitat as well as providing habitat for the
Southwestern Pond Turtle. The remaining 120 acres would be available for active recreational use.
"Old Town":
The channel width for the "Old Town" Tcmecula se~rncnt would be the same width as in Alternative
1. With velocity reduced from the RCFCD proposal of 17 FPS to 9 FPS, substantial design alumlativcs
for the "Old Town" section including changes in materials and channel shape would be possible. Slick
concrete would no longer be necessary nor would a straight "box" channel. The use of the concrete
floater slab would no longer be necessary because of the reduction in velocity.
General:
Total land acquisition would require 90 acres more land than the RCFCD proposal for channel and fight
of way plus 85 acres for Southwestern Pond Turtle nesting areas plus 200 acres for swrm water
detention. Biological monitoring would be provided for a minimum of five years after installation of
plant materials.
This alternative has an estimated cost of 65.4 Million dollars including fight of way acquisition and
additional lands for Southwestern Pond Turtle nesting areas. (See Table 2)
Mitigation Measures Incorporated in Channel Design:
Erosion:
The design velocity of 5 FPS will substantial reduce erosiveness of the water. The planting of native
and turf grasses to provide a uniform ground cover will also help to control erosionL' The use of energy
4/911993
U.R.G .E.
Project Alternatives
dissipating devices at the entrance of tributary flow will reduce erosion. The use of relatively fiat side
slopes, average 8/1 will reduce the effects of erosion.
Siltation:
The reduction of erosion within the channel will substantially reduce the siltation problems within the
channel. The use of energy dissipators at tributary entrances will deposit silt in controlled locations.
The maintenance of velocities of 5 FPS would significan~y reduce the silt carrying capability of flood
flows. The detention basins will provide controlled locations where most silt deposition will occur as
a result of extremely low velocity.
Water Quality:
The use of wetlands to ~ter pollutants will improve water quality. The reduced erosion and siltation
will also improve water quality. The capability of substantial additional groundwater recharge as a result
of project design will also reduce the degradation of groundwater sources.
Groundwater Recharge:
The proposed channel will provide approximately 370 acres more wetted area for recharge than the
RCFCD mitigated channel. The 200 acres of detention areas, designed to detain 5,000 acre feet of water
will provide a substantial new source of recharge. With velocities 1/'2 to 2/3 those of the RCFCD
proposal, substantially more groundwater recharge possibilities exist
Riparian Habitat:
The project will disturb approximately 60 acres of riparian habitat, This alternative will provide
approximately 70 acres of riparian habitat within the habitat corridor and an additional 80 acres within
the detention basins. URGE feels that the quality of the overall habitat environment is far superior to
that proposed by RCFCD. Reduced velocity and reduced siltation will result in less impact to the
riparian habitat. As a result of the reduced siltation, it will not be necessary to periodically remove and
replant the habitat thus allowing a more mature development of the habitat
Wetlands:
This proposal would impact approximately 60 acres of weftands. The low flow channel will provide
approximately 70 acres of weftands. The 80 acres of detention basins designated for riparian habitat
will also provide substantial weftands. Additionally, weftands areas are proposed at each tributary
entrance. The 100 foot native gras~lands buffers on either side of the low flow channel will allow the
redevelopment of weftands where the hydrologic regime will permit, Given the opportunity to develop,
those areas which were previously weftands will return as wetlands. Wetlands will be less subject to
impact as a result of lower velocity and less siltation.
Southwestern Pond Turtle:
ReviMd: 4/911993
U.R.G.E.
Project Alternatives
This Category 1 candidate for Federal listing is known to inhabit Murrieta Creek. A shell was identified
during the wetlands delineation. The inclusion of ponding areas within the channel, at intervals of less
than one mile, will provide additional habitat opportunities. The rehtively fiat ( average 8/1 H/V ) will
allow unrestricted movement from habitat areas in the creek to nesting areas outside the creek. Nesting
areas would be provided outside the 100 year flood elevation. These nesting areas are proposed to be
six hundred feet wide and six hundred feet deep. This will equal nearly one half the maximum normal
travel distance for this species. Nesting areas would provide a hard packed clay surface with a costal
sage covering and would provide south facing slopes. Nesting areas would also be provided in the areas
between the creek and detention basins. Channel areas between the low flow channel and nesting areas
would be native grasslands with elements of the costal sage scrub community. Velocity proposed by
the RCFCD exceeds that acceptable for the Southwestern Pond Turtle. Proposed velocities of 5 FPS for
this alternative are consistent with the habitat requirements for the species.
Least Be!!'s Vireo:
The provision of the riparian habitat corridor will some assistance in migration. The creation of two 40
acre riparian habitat areas in detention basins will provide beneficial habitat for the Least Bell's Vireo.
These habitat areas will be adjacent to and connected with the habitat corridor. The overall naturalness
of the channel compared to the RCFCD will assist in its viabiLity for its use by the Least Bell's Vireo.
California Gnatcatcher:
The project is only expected to disrupt 3.36 acres of costal sage scrub habitat. With the addition of the
detention areas, the project will create or preserve approximately 85 acres of costal sage scrub habitat
for the Southwestern Pond Turtle nesting areas and 72 acres of costal sage on the slopes of the detention
basins. Individual nesting areas for the turtle will be less than l0 acres each and are thus not expected
to provide beneficial habitat. The placement of these areas adjacent to the habitat corridor and detention
basins, combined with the more natural appearing channel development will improve the viabiLity of its
use by the Gnatcatcher.
Animal Migration:
The 50 foot ripman habitat corridor in conjunction with the I00 foot native grassland buffers on either
side will provide a continuous north south habitat corridor for animal migration. This corridor will be
enhanced by the use of the ponding areas which will serve as watering areas. The viability of the habitat
corridor will be enhanced by the creation of the Southwestern Pond Turtle nesting areas outside the 100
year flood plain but contiguous with the habitat corridor. The adjacent detention basins will provide an
additional 152 acres of habitat adjacent to the corridor, substantially improving its effectiveness. As a
result of the reduced velocity, 5 FPS, reduced erosion and siltation, there will be less impact on the
habitat corridor from flood events thus permit~g a more mature development of the habitat. The
reduction of the side slopes from 2/1 as proposed by RCFCD will permit unrestricted wildlife movement
east west across the creek..The reduced side slopes will permit the movement of the Southwestern Pond
turtle from the habitat area w nesting areas. Since reduced velocity reduces the public safety hazard,
fencing will not be required thus removing that potential barrier to wildlife movement. The more natural
overall appearance of the channel will make the habitat corridor more viable.
R,vim!: 4/911993 8
U.R.G.E.
Project Alternatives
Downstream Habitat:
Peak flows will be reduced from 38500 CFS to approximately 29,000 CFS under this alternative. This
represents an approximate 25% reduction in peak flows. Additionally, the exit velocity from the "Old
Town Segment will be reduced from 17 FPS to 9 FPS. Velocity would be decreased even more south
of Main Street. Reduced volume and velocity combined with a reduced silt load would reduce but not
eliminate downstream habitat destruction.
Local Flooding:
The channel design for atis alternative would provide accommodate approximately 9,500 FPS more water
than the RCFCD plan as a result of detention. This represents a maximum flow of over thirty percent
greater than the 100 year flow. This would provide flood protenon well above 100 year levels.
Downstream Flooding:
As a result of detention, downstream flooding volumes would be reduced by approximately 25%. This
does represent approximately 32% more volume than currently is released but a substantial improvement
over both the RCFCD plan or URGE Alternative 1.-
Visual Resources:
The reduction of side slopes from a :2/1 side slope as proposed by RCFCD to an average of 8/1 will
reduce the visual impact by the elimination of the obvious manmade 2/1 slopes. Additionally, the side
slopes will utilize variable slopes designed to simulate natural terrain. Berms or moguls utilized in pan
to control velocity will also break the straight line appearance. The elimination of the armorflex and
its attendant problems or erosion of the soil covering will also reduce the visual impact of the project.
As a result of the elimination of fencing throughout most of the length of the project, another discordant
element is removed. The provision of 100% planting for the channel will provide a more uniform
appearance. A neater appearance will be maintained as a result of less erosion and siltation. Within the
"Old Town" Temecula section, reduced volumes and velocities will provide a much greater choice of
architectural treatment for the channel including channel shape. Decorative paving in the "Old Town"
section would transform the normally negative influence of an unpaved access road into a "promenade"
which could serve as an enhancement to local businesses.
Land Use:
Mitigation for land use impacts within the channel dcsign include those measures discussed in the public
safety and visual resource discussions. These measures will make the channel more compatible with all
land uses. The greenbelt approach embodied in this alternative is more compatible with the Draft Land
Use Plan policies and map for the City of Murrieta.
Public Safety:
The primary public safety impacts created by the RCFCD arc as a result of the steep side slopes and
Rivined: 419119t3 9
U.R.G.E.
Project Alternatives
high velocity of flow in the channel. The amount of force exerted on a body by water flowing at 3
MPH is thirty-five pounds. At 6 MPH this force increases to 140 pounds. At 12 miles per hour this
increases to 540 pounds. This alternative has eliminated these impacts through the use of relatively fiat
, average 8/1, side slopes and a reduction in design velocity to 5 FPS. The channel design will also
allow a gradual decrease in velocity as you near the outside of the channel thus allowing someone
trapped to swim toward the outside where force is reduced even more. Once reaching the outside it will
bc possible to climb out of the channel
Recreational Use:
The project design incorporates two multi use trails at the top of the slope. The channel design, because
of its fiat side slopes will accommodate additional trails. The project will provide 230 acres of lands
for habitat use which will be generally be unavailable for use. There will be approximately 200 acres
of native grasslands which could be u'ttlized for low impact passive use. One hundred sixty acres of land
would be available for active recreational use within the channel. Areas would generally be small
enough to provide space only for playgrounds, volleyball or basketball use. There would not be
sufficient width for activities such as soccer, softball or football. There will be two trails for the full
length of the projecL The detention basins.would provide 120 acres of land available for development
of active recreational uses including softball, baseball, football, soccer, tennis, golf or any number of
other possible uses.
For a summary of alternative impacts see Table 3.
URGE Alternative 3
URGE Alternative 3 incorporates a parkway channel with channel fight-of-way widths varying from 360
to 480 feet (See Table 1) This channel would be donsized from Alternatives l&2. The channel would
be designed to carry a peak flow of 29,000 CF3. The 100 year flood flow would be reduced to
approximately 20,000 CFS. The channel would be capable of handling flows approximately 9,000 C_.FS
greater than 100 year flows.
Storm water detention:
Alternative 3 incorporates a Wtal of 10,000 acre feet of storm water detention. It is proposed that there
be ten detention areas, each with a nominal size of 40 acres. These detention areas would be located
primarily within the existing 100 year flood plain approximately 100 feet from the creek. The area
U.R.G .E.
Project Alternatives
between the detention basin and the creek would be planted with costal sage scrub species. Side slopes
of the detention areas would also be planted using typical costal sage scrub materials. Each detention
area would be excavated to an average depth of 25 feel Location at the con~uence of tributaries would
maximize potential benefiL Marsh areas would be incorporated in the low flow channels of the detention
basins to capture the first flush and remove pollutants. It is proposed that two areas, for a total acreage
of 80 acres be devoted to the establishment of riparlan habitat as well as providing habitat for the
Southwestern Pond Turtle. A total of 120 acres would be available for active recreational use. The
remaining 200 acres could be utilized as recreational areas, grazing lands or any of a number of
activities.
"Old Town":
The channel width for the "Old Town" Temecula segment would be the same width as in Alternative
l&2. With velocity reduced from the RCFCD proposal of 17 FPS to 6.25 FPS, substantial design
alternatives for the "Old Town" section including changes in materials and channel shape would be
possible. Slick concrete would no longer be necessary nor would a straight "box" channel. The use of
the concrete floater slab would no longer be necessary because of the reduction in velocity.
General:
Total land acquisition would/v. quire approximately 40 acres more land than the RCFCD proposal for
channel and right of way plus 100 acres for Southwestern Pond Turtle nesting areas and 400 acres for
storm water detention. Biological monitoring would be provided for a minimum of five years afar
installation of plant materials.
This alternative has an estimated cost of 74.8 Million dOllarS including right of way acqulsilion and
additional lands for Southwestern Pond Turtle nesting areas. (See Table 2)
Mitigation Measures Incorporated in Channel Design:
Erosion:
U.R.G .E.
Project Alternatives
The design velocity of 5 FPS will substantial reduce erosiveness of the water. The planting of native
and tuff grasses to provide a uniform ground cover will also help to control erosion. The use of energy
dissipating devices at the entrance of tributary flow will reduce erosion. The use of relatively fiat side
slopes, average 8/1 will reduce the effects of erosion.
Siltation:
The reduction of erosion within the channel will substantially reduce the siltation problems within the
channel. The use of energy dissipators at tributary entrances will 'deposit silt in controlled locations.
The maintenance of velocities of 5 FPS would significan~y reduce the silt canying capability of flood
flows. The detention basins will provide controlled locations where most silt deposition will occur as
a result of extremely low velocity.
Water Quality:
The use of weftands to ~ter pollutants will improve water quality. The reduced erosion and siltation
will also improve water quality. The capability of substantial additional groundwater recharge as a result
of project design will also reduce the degradation of groundwater sources.
Groundwater Recharge:
The proposed channel will provide approximately 320 acres more wetted area for recharge than the
RCFCD mitigated channel. The 400 acres of detention areas, designed to detain 5,000 acre feet of water
will provide a substantial new source of recharge. With velocities 1/'2 to 2/'3 those of the RCFCD
proposal, substantially more groundwater recharge possibilities exist.
Riparian Habitat:
The project will disturb approximately 60 acres of riparian habitat. This alternative will provide
approximately 70 acres of riparian habitat within the habitat corridor and an additional 80 acres within
the detention basins. URGE feels that the quality of the overall habitat environment is far superior to
that proposed by RCFCD. Reduced velocity and reduced sfltation will result in less impact to the
riparian habitat. As a result of the reduced silta~on, it will not be necessary to periodically remove and
replant the habitat thus allowing a more mature development of the habitat.
Wetlands:
This proposal would impact approximately 60 acres of wetlands. The low flow channel will provide
approximately 70 acres of wetlands. The 80 acres of detention basins designated for riparian habitat
will also provide substantial wetlands. Additionally, wetlands. areas are proposed at each tributary
entrance. The 100 foot native grasslands buffers on either side of the low flow channel will allow the
redevelopment of wetlands where the hydrologic regime will permit.
those areas which were previously wetlands will return as wetlands.
impact as a result of lower velocity and less siltation.
U.R.G .E.
Project Alternatives
Given the opportunity to develop,
Wetlands will be less subject to
Southwestern Pond Tur~e:
This Category 1 candidate for Federal lisdng is known to inhabit Murrieta Creek A shell was identified
during the wetlands delineation. The inclusion of ponding areas within the channel, at intervals of less
than one mile, will provide additional habitat opportunities. The relatively fiat ( average 8/1 H/V ) will
allow unrestricted movement from habitat areas in the creek to nesting areas outside the creek. Nesting
areas would be provided outside the 100 year flood elevation. These nesdng areas arc proposed to be
six hundred feet wide and six hundred feet deep. This will equal nearly one haft the maximtun normal
t~avcl distance for this species. Nesting areas would provide a hard packed clay surface with a costal
sage covering and would provide south facing slopes. Nesting areas would also be provided in the areas
between the creek and detention basins. Channel areas between the low flow channel and nesting areas
would be native grasslands with elements of the costal sage scrub community. Velocity proposed by
the RCFCD exceeds that acceptable for the Southwestern Pond Turtle. Proposed velocities of 5 FPS for
this alternative arc consistent with the habitat requirements for the species.
Least Be!i's Vireo:
The provision of the ripman habitat corridor will some assistance in migration. The creation of two 40
acre riparian habitat areas in detention basins will provide beneficial habitat for the Least BeH's Vireo.
These habitat areas will be adjacent to and connected with the habitat corridor. The overall naturalness
of the channel compared to the RCFCD will assist in its viability for its use by the Least Be!l's Vireo.
California Gnatcatcher:
The project is only expected to disrupt 3.36 acres of costal sage scrub habitat. With the addition of the
detention areas, the project will create or preserve approximately 100 acres of costal sage scrub habitat
for the Southwestern Pond Turtle nesting areas and 144 acres of costal sage on the slopes of the
detention basins. Individual nesting areas for the turtle will be less than l0 acres each and are thus not
expected to provide beneficial habitat. The phcement of these areas adjacent to the habitat corridor and
detention basins, combined with the more natural appearing channel development will improve the
viability of its use by the Gnatcatcher.
Animal Migration:
The 50 foot riparian habitat corrido~ in conjunction with the 100 foot native grassland buffers on either
side will provide a continuous north south habitat corridor for animal migration. This corridor will be
enhanced by the use of the ponding areas which will serve as watering areas. The viability of the habitat
corridor will be enhanced by the creation of the Southwestern Pond Turtle nesting areas outside the 100
year flood plain but contiguous with the habitat corridor. The adjacent detention basins will provide an
additional 224 acres of habitat adjacent to the corridor, substantially improving its effectiveness. As a
result of the reduced velocity, 5 FPS, reduced erosion and S~iltation, there will be less impact on the
U.R.G.E.
Project Alternatives
habitat corridor from flood events thus permitling a more mature development of the habitat. The
reduction of the side slopes from 2/1 as proposed by RCFCD will permit unrestricted wildlife movement
east west across the creek. The reduced side slopes will permit the movement of the Southwestern Pond
turtle from the habitat area to nesting areas. Since reduced velocity reduces the public safety hazard,
fencing will not be required thus removing that potentin] barrier to wildlife movement. The more natural
overall appearance of the channel will make the habitat corridor more viable.
Downstream Habitat:
Peak flows will be reduced from 38,500 CFS to approximately 20,000 CFS under this alternative. This
represents an approximate 48% reduction in peak flows and a 9% reduction from current levels.
Additionally, the exit velocity from the "Old Town Segment will be reduced from 17 FPS to 6.25 FPS.
Velocity would be decreased even more south of Main Street. Reduced volume and velocity combined
with a reduced silt load would reduce downstream habitat destruction below current levels.
Local Flooding:
The channel design for this alternative would provide accommodate approximately 9,500 FPS more water
than the RCFCD plan as a result of detention. This represents a maximum. flow of over thirty percent
greater than the 100 year flow. This would provide flood protection well above 100 year levels.
Downstream Flooding:
As a result of detention, downstream flooding volumes would be reduced by approximately 48%. This
represent approximately 9% less volume than curren~y is released.
Visual Resources:
The re'duction of side slopes from a 2/1 side slope as proposed by RCFCD to an average of 8/1 will
reduce the visual impact by the elimination of the obvious manmade 2/1 slopes. Additionally, the side
slopes will utilize variable slopes designed to simulate natural terrain. Benns or moguls utilized in pan
to control velocity will also break the straight line appearance. The elimination of the armorflex and
its attendant problerns or erosion of the soil covering will also reduce the visual impact of the project.
As a result of the elimination of fencing throughout most of the length of the project, another discordant
element is removed. The provision of 100% planting for the channel will provide a more uniform
appearance. A nearer appearance will be maintained as a result of less erosion and siltation. Within the
"Old Town" Temecula section, reduced volumes and velocities will provide a much greater choice of
architectural treatment for the channel including channel shape. Decorative paving in the "Old Town"
section would u~msform the normally negative influence of an unpaved access road into a "promenade"
which could serve as an enhancement to local businesses.
Land Use:
Mitigation for land use impacts within the channel design include those measures discussed in the public
safety and visual resource discussions. These measures will make the channel more compatible with all
U.R.G .E.
Project Alternatives
land uses. The greenbelt approach embodied in this alternative is more compatible with the Draft Land
Use Plan policies and map for the City of Murrieta. The possible use of additional detention areas for
grazing could help reduce the financial impact of the project to the residential areas adjacent to the creek.
Public Safety:
The primary public safety impacts created by the RCFCD arc as a result of the steep side slopes and
high velocity of flow in the channel. The mount of force exerted on a body by water flowing at 3
MPH is thirty-five pounds. At 6 MPH this force increases to 140 pounds. At 12 miles per hour this
increases to 540 pounds. This alternative has eliminated these impacts through the use of relatively flat
, average 8/1, side slopes and a reduction in design velocity to 5 FPS. The channel design will also
allow a gradual decrease in velocity as you near the outside of the channel thus allowing someone
trapped to swim toward the outside where force is reduced even more. Once reaching the outside it will
be possible to climb out of the channel.
Recreational Use:
The project design incorporates two multi use trails at the top of the slope. The channel design, because
of its fiat side slopes will accommodate additional trails. The project' wiil provide 230 acres of lands
for habitat use which will be generally be unavailable for use. There will be appwximately 200 acres
of native grasslands which could be utiliTed for low impact passive use. One hundred ten acres of land
would be available for active recreational use within the channel. Areas would generally be small
enough to provide space only for playgrounds, volleyball or basketball use. There would not be
sufficient width for activities such as soccer, softball or football. There will be two trails for the full
length of the project. The detention basins would provide 120 acres of land available for development
of active recreational uses including softball, baseball, football, soccer, tennis, goff or any number of
other possible uses. An additional 200 acres of detention area would be available for uses which might
include recreation.
For a summary of alternative impacts see Table 3.
Z
~ ~ z
.
.~1
U
';
Ills
Station
38+00-62+70
67+00.108+71
113+00-126+00
129+00-166+00
167+50-176+50
178+00-248+00
250+00-395+00
397+00-445+00
447+00-470+00
472+00-602+00
TABLE 1
RCFCD Urge l&2
ROW AREA ROW AREA
370' 6858 484' 8700
160' 2400 200' 3200
400' 6468 570' 8700
480' 7800 560' 8060
460' 5868 590' 8160
400' 5282 490' 6400
340' 3712 470' 5520
270' 3072 470' 5520
340' 3450 470' 5250
300' 2525 360' 2800
U.R.G.E.
Project Alternatives
Urge 3
ROW AREA
400' 6525
200' 3200
460' 6525
480' 6045
460' 6120
400' 4800
380' 4140
380' 4140'
360' 3940
360' 3200
Revime4~/l~3
16
i
i ] i:
,t
CEQA REVIEW
URGE April 9, 1993
SUBJECT: 404 Permit and 1601 Notification for the Murrieta Creek Flood Control Channel
(92-724-RS)
BACKGROUND
In March of 1986, an initial study was prepared for "The Master Drainage Plan for the Murricta
Creek Arca", hereinafter referred to as the "Initial Study". In May of 1986 a Negative
Declaration for this master plan was adopted, hereinafter referred to as the "Negative
Declaration".
The Negative Declaration was intended as either a "Program" or "Staged" Negative Declaration
as page two of the initial study states "the master plan provides the basis for the adoption of an
ADP (Area Drainage Plan) by the County of Riverside. In this case, the master plan will provide
the basis for five separate sub-watersheds within the ADP. The County Planning Department
will prepare the Environmental Assessment for the ADP." The Initial Study reviewed a
conceptual Master Plan and clearly identified the need for further site specific environmental
review of implementing projects. No site specific environmental review of this project, as an
implementing activity of the Master Plan has been completed. Note that while the Initial Study
relied upon for this project was completed in 1986, the project plans were not completed until
1991.
CEQA REVIEW
The Initial Study and Negative Declaration for the Master Plan were seriously flawed in a
number of areas.
Procedure: While the project involved at least one responsible agency, the proposed
Negative Declaration was not circulated through OPR nor was the Negative Declaration filed
with OPR.
Format: The project description in the Initial Study did not provide adequate information
for an environmental review of the project The Initial Study did not provide plans or even
general location maps. Additionally, the format of the Initial Study did not include all of
the areas of potential impact required by the "Guidelines". The following areas were not
evaluated in the Initial Study:
Water. Will the proposal result in:.
a. changes in currents, or the course of direction of water movements, in either marine
or fresh waters?
1
URGE April 9, 1993
b. Changes in absorption rates, drainage patterns, or the rate and amount of surface
runoff?.
c. Alterations to the course or flow of flood waters7
e. Discharge into surface waters, or in any alteration of surface water quality,
including but not limited to temperature, dissolved oxygen or turbidity7
h. Substantial reduction in the amount of water otherwise available for public water
supplies7
i. Exposure of people or property to water related hazards such as flooding of tidal
waves?
4. Plant Life. Will the proposal result in:
a. Change in the diversity of species, or number of any species of plants, (including
trees, shrubs, grass, crops and aquatic plants)?
c. Introduction of new species of plants into an area, or in a barrier to the normal
replenishment of existing species7
5. Animal Life. Will the proposal result in:.
a. Change in the diversity of species, or numbers of any species of animals (birds,
land animals including reptiles, fish and shellfish, benthie organisms or insects)?
c. Introduction of new species of animals into~an area, or result in a barrier to the
migration or movement of animals?
d. Deterioration to existing fish or wildlife habitat7
6. Noise. Will the proposal result in:
b. Exposure of people to severe noise levels?
7. Light and Glare. Will the proposal produce new 'light of Glare?
8. Land Use. Will the proposal result in a substantial alteration of the present or planned
land use of an area?
10. Risk of Upset. Will the proposal involve:
A risk of an explosion or the release of hazardous substances )including, but not
limited to, oil, pesticides, chemicals or radiation) in the event of an accident or
upset conditions7
11. Population. Will the proposal alter the location, disu'ibution, density, or growth rate of
the human population of an area?
URGE April 9, 1993
12. Housing. Will the proposal affect existing housing, or create a demand for additional
housing7
17. Human Health. Will the proposal result in:
a. Creation of any health hnTnrd or potential health hazard (excluding mental health)?
18. Aesthetics. Will the proposal result in the obstruction of any scenic vista or view open
to the public, or will the proposal result in the creation of an aesthetically offensive site
open to public view7
19. Recreation. Will the proposal result in an impact upon the quality or quantity of
existing recreational opportunities7
Analysis: The Initial Study did not meet the test of AB2583 that requires that "the lead
agencies determination of whether a project may have a siSni~cant effect on the environment
be based on substantial evidence in the record". The Initial Study contains no studies for
hydrology, geology, soils, biota, paleontologic resources, archaeological resources, historic
resources, noise, air quality or any other issue. The Initial Stu~!y contains no quantitative
or qualitative substantiation of the claims of no potential significant impacts. As noted
above, many potential impacts were not considered. Some of the shortcomings in analysis
are detailed below.
Section H.A. 1 .a of the Initial Study indicated the project did not impact a marsh. Page 3-25
of the wetlands delineation identifies 53.51 acres of freshwater marsh including a turtle shell.
The Southwestern Pond Turtle (Clemmys marrnorata paRida), a Category I candidate for
federal listing as threatened or endangered, is known in this area.
Section H.A.I.c, soil instability identified potential impact. Substantiation indicated
"appropriate mitigation will be taken" - no mitigation is identified in the substantiation.
Section II.A. 1 .d identifies that the project is in an earthquake fault zone - No discussion of
possible impacts is provided. No mitigation is provided.
Section II.A.2.a identifies that the project is within a flood plain but provides no discussion
of the impact of the proposed project.
Section ILA.2.b identifies that the project will involve a natm'al drainage channel or
su'eambed--there is no discussion of possible impacts in spite of the fact that the project will
impact 109 acres of riparian habitat.
Section II.A.3.a identifies that there are rare and endangered species within the project area.
URGE April 9, 1993
The I.S. identifies the project as being in Stephan's Kangaroo Rat habitat but concludes that
the amount of habitat to be affected by the project is "small, compared to the total and,
therefore, adverse impacts are considered minimal". No mitigation is proposed for this
species. The Initial Study does not identify possible impacts to the Southwestern Pond
Turtle, a federal Category 1, candidate for listing, known to inhabit the project area.(This
week the USFWS recommended listing). There is no discussion of costal sage scrub or
Riverside alluvial fan Sage Scrub present in the project area and the California Gnatcatcher,
recently listed as threatened. There is no discussion of the Least Bills Vireo which possibly
inhabits the project area. No other possible species are discussed nor were studies provided
to determine the presence of rare or endangered species.
Section II.A.3.d-Could the project affect fish,, wildlife, reptiles or plant life7 The only
potential impact identified was to "underbrush and small trees." There was no other
discussion of potential impact.
Section r/.A.4.b- Will the project result in alteration to natural features -- "Most of the
channel excavations will be located within natural watercourses, therefore, disruption of the
terrain is minimal. - There was no discussion of the major impact of altering the primary
natural feature, the creek itself. no mitigation is provided.
In Section II.B. l .a. 1, pollution, there was no discussion of potential short term impacts other
than dust. Consu'uction activities may well exceed threshold for ozone precursors. PM10
emissions would most certainly exceed thresholds without substantial and detailed mitigation.
The only mitigation provided is "This will be contrrolled by watering."
In Section II.B.l.a.4, the application or use of potentially hazardous materials, 'the only
potential impact discussed is aa result to the use of herbicides which is dismissed as being
"minimal ". There is no discussion of potential impact as a result or possible fuel spills. No
mitigation is provided.
In Section II.C. 1.a., land use, there is no discussion of potential impact for land use other
than the acquisition of land for flood control right of way.
In Section II.C.3., Social/Cultural impact, the Initial Study indicates that "much of the project
site has not been surveyed" for culture resources. The Initial Study requires that a study be
completed for those areas which may have "historical cultural significance." "If appropriate,
resource recovery and documentation would be performed.
4
URGE April 9, 1993
Significance: As a result of faulty or incomplete analysis and substantiation, the Initial
Study failed to identify potentially significant impacts in the following areas identified in
appendix G of the "Guidelines":
(b) Have a substantial, dernonstrable, negative aesthetic effect
(c) Substantially affect a rare or endangered species of animal or plant or the habitat of the
species
(h) Substantially degrade of deplete ground water resources
(i) Interfere substantially with ground water recharge
(j) Disrupt or adversely affect a prehistoric or historic archaeological site or s property of
historic or cultural significance to a community or ethnic or social group; or a
paleontological site except as a apart of a scientific study
(q) Cause substantial flooding, erosion or siltation
(t) Substantially diminish habitat for fish, wildlife or plants
(x) Violate any ambient air quality standard, contribute substantially to an existing or
projected air quality violation, .or expose .sensitive reccptors to substantial pollutant
concentrations
Mitigation: The CEQA Guidelines, in section 15021 require:
(a) CEQA establishes a duty for public agencies to avoid or minimize environmental
damage where feasible.
(1) In regulation public or private activities, agencies are required to give major
consideration to preventing environmental damage.
(2) A public agency should not approve a project as proposed if there are feasible
alternatives or mitigation measures available that would substantially lesson any
significant effects that the project would have on the environment.
(b) In deciding whether changes in a project are feasible,an agenCy may consider specific
economic, envirotwaental, legal, social and technological factors.
(c) The duty to prevent or minimize environmental damage is implemented through the
fitutings required by Section 15091.
(d) CEQA recognizes that in determining whether and haw a project should be approved,
a public agency has an obligation to balance a variety of public objectives, including
economic, environmental, and social factors and in particular the goal of providing a decent
home and satisfying living environment for every Californian. An agency shah prepare a
statement of overriding considerations as described in Section 15093 to reflect the ultimate
balancing of competing public objectives when the agency decides to approve a project that
will cause one or more significant effects on the environment.
In spite of this requixement, the only mitigation measures required in the Initial Study were
for unspecified watering to reduce dust during construction and archaeologic studies for areas
5
URGE April 9, 1993
with a high probability of archaeological resources. One measure is too vague to be
implemented and insure non-significance since it provides no performance standards, and the
other is clearly conlrary to the opinion in Sundsmxrn V. County of Mendocino in .that it
simply requires future study and provides for no implementation of mitigation measures.
The following new environmental impacts were not identified in the 1986 Initial Study:
At peak flows discharge 38,000 CFS into the unprotected riparian habitat
downstream at velocities of 16 feet per second.
Based upon historic data, approximately 500,000 cubic yards of silt per year will
be discharged into the sensitive CDFG holdings.
The Filling of much of the flood plain will add substantial land available for
commercial and industrial development immediately adjacent to this drainage
facility, thus further increasing runoff, decre~__sing time of concentration and
potentially adding sources of pollution to the water.
Have a substantial, demonstrable, negative aesthetic effect.
Substantially affect a rare or endangered species of animal or plant or the habitat
of the species.
Substantially degrade of deplete ground water resources as a result in substantial
reductions in recharge.
Interfere substantially with ground water recharge as a result of substantial
reductions in recharge area and substantially increasing the rate of flow of storm
waters, thus reducing opportunities for recharge.
Cause substantial flooding at the downstream end of the project as well as on the
Santa Margarita River; erosion and siltation as a result of discharging from armored
channels at the rate of 38,000 CFS and a velocity of 16 feet per second.
Substantially diminish habitat for fish, wildlife or plants with a direct loss of 109
acres of riparian habitat.
The channel as proposed will serve as an effective barrier to wildlife migration and
movement over its entire eleven mile length.
Substantial changes have occurred with respect to the circumstances under which the project
w~l be undertaken. These changes lead to potentially significant impacts not evaluated in
the previous environmental review. These changes include:
* The acquisition of a substantial riparian area just downstream from the proposed
project by the California Department of Fish and Game.
* The recognition of ~he importance of the CDFG holdings as fiparian habitat and its
potential importance as habitat for the Least B~ls Vireo.
The designation of Costal Sage Scrub, including Riverside Alluvial Fan Sage Scrub
as a habitat of special concern and the listing of the California Gnatcatcher as
6
URGE April 9, 1993
threatened.
The listing of the Southwestern Pond Turtle as a Category 1 candidate for federal
listing, with a recent recommendation for listing, and the discovery that this species
inhabits the project area and that shell fragments have been found on the project
site.
With the development of the plans and studies, it has been determined that the project will:
* At peak flows discharge 38,000 CFS into the unprotected riparian habitat
downstream at velocities of 16 feet per second.
* Based upon historic data, approximately 500,000 cubic yards of silt per year will
be discharged into the sensitive CDFG holdings.
* The filling of much of the flood plain will add substantial land available for
commercial and industrial development immediately adjacent to this drainage
facility, thus further increasing runoff, decreasing time of concentration and
potentially adding sources of pollution to the water, and;
The project will have the following significant effects not discussed in the 1986 Initial Study:
* Reduction in Coastal Sage Scrub
* Reduction of Riparian habitat including fresh water marsh
* Impact to the habitat and possible take of the Southwestern Pond Turtle
* Substantial deterioration of the critical habitat immediately downstream including
potential L~ast Bills Vireo habitat
* Significant reduction of ground water recharge
* Significant degradation of surface water quality as a result of discharging 38,000
CFS at a velocity of 16 feet ,per second into unprotected channel. with the
accompanying increased turbidity
* The channel as finally developed will serve as an effective barrier to wildlife
migration and movement over its entire eleven mile length
* Public Safety as a result of steep side slopes' and high velocities.
The following impacts wR1 be substantially worse than discussed in the previous Initial
Study:
* Aesthetics - as identified in community input meetings for the City of Murrieta
General Plan
* Land use - initial drafts of policies for the City of Murrieta General Plan call for
Murrieta Creek and'Warm Springs Creek to remain as natural channels
* Biotic resources as a result of specific channel design and its impact as a barrier to
wildlife movement
* Diminishment of wildlife habitat.
* Groundwater recharge
URGE April 9, 1993
* Downstream erosion and siltation
* Downstream flooding
* Air quality
Numerous mitigation measures and design alternatives' would be available to reduce the
potential impacts. The 1986 Initial Study included no mitigation measures for:
* Groundwater recharge
* Biotic resources
* Erosion or sedimentation
* Downsweam flooding
* Aesthetics
* Land use
* Recreation
* Cultural resources
* Paleontologic resources
* Water quality
* Public Safety
* Hazardous materials
PROJECT ALTERNATIVES IDENTIFIED IN THE 404 PERMIT APPLICATION:
The alternative analysis is biased toward the proposed project or the "mitigated channel"
alternatives by virtue of the alternatives selected for review and the assumptions made in the
alternatives.
The mitigated channel alternative is suggested as being environmentally superior on the basis
of providing replacement riparian habitat and providing a migration corridor for wildlife. These
claims are viewed with some skepticism due to the fact that the riparian plants to be installed
would have to survive inundation under twenty feet of Water at velocities of sixteen feet per
second during flood conditions. The usefulness as a habitat corridor is also speculative as a
result of either vertical or 2:1 side slopes which would preclude use by many species. The use
of the riparian area as an equestrian wail would also substantially diminish its value as a habitat
corridor. There was no analysis of public safety issues.
The parkway channel alternative indicates that channel slopes of 5:1 are adequate and often
utilized, but side sloops of 12:1 were arbitrarily utilized. It was asstuned that this would require
an additional 600 feet of right of way or 771 acres. The analysis indicated that right-of-way
acquisition would be too costly. In reality, based upon calculations, only approximately 86 acres
of additional right of way would be required. Drainage easements, rather than outright right-of-
way acquisition could be utilized at much lower cost. It should also be noted that with the
implementation of detention measures, drainage way improvements would require less land. In
URGE April 9, 1993
Murrieta Creek, the land required for channel improvements is within the 100 year flood plain
and is thus unbuildable.
The detention basin alternative only addresses the acquisition and development of three major
detention basins. The selection of only three basins would require substantial land acquisitions
which have biased the alternative. This alternative should look at the possibility of numerous
smaller detention basins excavated within the flood plain which could in many cases be located
within existing right-of-way, drainage easements, or open space easements and required as
mitigation for future development projects.
The on-site detention alternative is biased in that it is not a detention alternative as the name
implies, but rather a retention alternative. The alternative requires that water be stored on site
until it percolates into the ground or evaporates rather than detaining it for gradual release over
a longer period of time. This alternative is further biased by the assumption that all land for
retention must .be purchased as a part of the project cost rather than as specific future
development project mitigation.