HomeMy WebLinkAboutAGENDA REPORT 2005 0216 CC REG ITEM 09Ar
CITY OF MOORPARK, CALIFORNIA
City Council Meeting
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ACTION:
BY: `7 _
MOORPARK CITY COUNCIL
AGENDA REPORT
TO: Honorable City Council 7
FROM: Brad Miller, City EngineerlC / %��
DATE: February 04, 2005 (CC Meeting of 2/16/05)
SUBJECT: Report on January 2005 Winter Storm
BACKGROUND
During the last week of December 2004, and the first week of
January 2005, a series of wet Pacific storms moved through our
area in rapid succession. While the rainfall events immediately
prior to January 9, 2005 had been of light to moderate
intensity, the two weeks of steady rainfall had already begun to
create saturated soil conditions in the watersheds in and around
Moorpark. On the morning of Sunday, January 9, 2005, a series
of extremely high intensity storm cells passed through Ventura
County, generating near record rainfall at many locations in and
around Moorpark.
DISCUSSION
By 9:00 AM on Sunday morning, January 9, 2005, extremely heavy
rainfall was causing problems at several locations in Moorpark.
Mudslides were occurring on Gabbert Road north of Poindexter,
blocking the street. Mudslides were occurring along portions of
Princeton Avenue, (formerly Los Angeles Avenue), between Spring
Road and Nogales Avenue, requiring closure of the roadway.
Mudslides were also beginning to occur along Walnut Canyon,
north of Casey Road and by 10:00 that morning Caltrans had
closed Route 23 at Everett Street.
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Honorable City Council
February 16, 2005
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Los Angeles Avenue and the Villa Del Arroyo Mobile Home Park
As this intense storm cell moved north over Moorpark College and
Happy Camp Canyon, the extremely heavy rainfall generated runoff
that scoured silt and debris from the steep canyon slopes
throughout the watershed. This heavily silt laden runoff flowed
south out of the watersheds northeast of Moorpark, and first
appeared along Los Angeles Avenue east of Collins Drive. A
heavy surge of runoff from Canyon No. 2, (northeast of Moorpark
College), overwhelmed the Ventura County Watershed Protection
District Debris Basin that is under construction just north of
the 118 Freeway, and east of the easterly terminus of Campus
Park Drive. The powerful surge of water damaged the new debris
basin structure and access road, and then breeched the Drain No.
2 roadway culvert that passes under Los Angeles Avenue, (located
just west of the railroad crossing). The surge of water
overtopped the Drain No. 2 roadway culvert, knocking down
protective fencing, and flowing over Los Angeles Avenue, making
the road impassable.
This flooding of Los Angeles Avenue east of Collins Drive
temporarily stranded the residents of the Villa Del Arroyo
Mobile Home Park, since Los Angeles Avenue had also been closed
by Simi Valley, east of the Moorpark City limit. At the same
time, a heavy surge of silt and debris laden water appeared at
the railroad culvert directly across Los Angeles Avenue from the
main entrance to the Villa Del Arroyo Mobile Home Park. The
heavily laden water quickly overwhelmed and literally buried the
existing storm drain inlet that normally receives water from
this railroad culvert. Compounding this problem was the fact
that the privately owned and maintained drain that receives
water from this roadway culvert, and conveys it across the Villa
Del Arroyo Mobile Home Park, had not been cleared of earlier
blockages, and was partially obstructed at the beginning of this
storm. This sent the mud and water onto the Los Angeles Avenue
right of way, and consequently surface flowed into the Mobile
Home Park entrance driveway, threatening several homes. By 9:00
AM Sunday morning Ventura County Emergency Fire and Rescue units
had taken up positions at the Collins Drive and Los Angeles
Avenue intersection, closing Los Angeles Avenue east of Collins
Drive and for a time considered evacuating the Villa Del Arroyo
Park residents. Once the flooding at the No. 2 Drain culvert
subsided, allowing easterly access on Los Angeles Avenue,
Ventura County Emergency Fire and Rescue crews began deploying
sandbags at the outlet of the railroad culvert in an attempt to
divert the mud and water on Los Angeles Avenue away from the
Villa Del Arroyo homes.
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Honorable City Council
February 16, 2005
Page 3
Water had also become trapped in a low lying segment of Los
Angeles Avenue, east of the Park entrance, and had risen to a
depth where it began to threaten the north perimeter wall of the
Park. Residents were temporarily directed to use the normally
gated Ventura County Watershed Protection District access road
along the bank of the Arroyo to come and go from the Mobile Home
Park. Ventura County crews succeeded in diverting the mud flow
away from the Park driveway, sending it west on Los Angeles
Avenue and into other storm drain inlets that were still
functional. This temporary diversion dam constructed on Los
Angeles Avenue required constant monitoring and rebuilding by
Ventura County Fire crews throughout the morning, and later by
Moorpark City crews.
Moorpark City crews worked until 2:00 AM Monday morning keeping
the flows away from the Park entrance. At times working under
the headlights of two pickup trucks, the City of Moorpark's
Street and Parks crew worked around the clock, using hand tools
and our one light duty tractor, to protect our residents and try
to re -gain use of our roadways.
Happy Camp Canyon
At approximately 10:30 AM Sunday morning, the runoff from the
same intense storm cell began to appear as a "flash flood"
runoff surge flowing down Happy Camp Canyon. The low lying area
located at the inlet of the Happy Camp Canyon Channel, northwest
of Cambridge Street, was filled to capacity with silt in a
matter of minutes. The heavily silt and debris laden flow
overwhelmed the low flow de- silting area, and soon elevated the
area north of the channel inlet with silt. The silt buildup
shifted much of the water flow path easterly, soon threatening
the facility access road and the rear yard walls of the homes
along Cambridge Street. Eventually the silt build -up caused the
flow of water to re- direct itself east and onto the northerly
terminus of Campus Park Drive. The mud and silt laden flow
continued south along Campus Park Drive, over - topping the curbs,
sidewalks, and landscaping, and clogging catch basins with
debris.
Once the flow reached the low point on Campus Park Drive, it
turned south on Penn Street, a private residential road. The
flow became trapped at the south terminus of Penn Street,
ponding against the south perimeter wall of the residential
neighborhood. For a time, the flow greatly exceeded the
capacity of the existing drain at the south end of Penn Street,
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Honorable City Council
February 16, 2005
Page 4
and appeared that it would continue to rise and threaten
residences. Fortunately the water level eventually subsided as
crews cleared catch basins upstream on Campus Park Drive, and
diverted more of the flow into storm drains.
Ventura County Fire Department units and Moorpark City crews
worked throughout the morning to isolate Campus Park Drive for
safety, and keep storm drain inlets clear. Simultaneously,
Ventura County Fire and Rescue crews were assisting residents
along Cambridge Street in efforts to protect their rear yard
walls threatened by the flood water and debris. The Ventura
County Watershed Protection District deployed equipment and
manpower to remove silt from their earthen channel just north of
the Happy Camp channel and to restore their damaged access road.
A byproduct of those efforts was the construction of a berm just
north of the access road which provided additional protection
for the road and the houses along Cambridge Street. In addition,
a separate but related effort was undertaken by the owner of the
property north of the Watershed Protection District's
facilities. On Tuesday, January 11, 2005, the Ventura County
General Services Administration retained a contractor to remove
silt from the "silted -up" watercourse through the Golf Course
property, and construct a berm to prevent a reoccurrence of the
flooding of Campus Park Drive. Fortunately, the "flash flood"
surges of water were of limited duration, and with the heavy
equipment working, the threat to the homes on Cambridge Street
was brought under control.
A 200 Year Storm
As described by Ken Gilbert in his January 31, 2005 Report on
Happy Camp Drainage, (Attachment No. 1), staff has learned from
the Ventura County Watershed Protection District that certain
areas of the County were hit harder than others. The intense
storm cell that passed over Moorpark and the watersheds north of
town delivered rainfall totals that measured over 15 inches of
rain during the three day storm. During one twenty -four hour
period, over 8 inches of rain were recorded, equating to a 200
year storm intensity. As bad as this storm was, and it has been
reported by many long time residents as the worst in recent
memory, our community survived quite well overall. This intense
rainfall, equating to a 200 year event in localized areas, has
helped staff to identify areas of strength and weakness in our
existing flood control systems.
On the positive side, many areas of town that would have
otherwise been very hard hit by "flash flood" surges from the
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Honorable City Council
February 16, 2005
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northern watersheds were shielded by the erosion control
measures constructed by the various residential developments
north of town. The erosion control check dams and large
detention basins constructed on the Pardee, William Lyon, and
Toll Brothers housing projects suffered heavy damage from the
storms, but they succeeded in stopping the mud and debris flows
from the north that otherwise would have flowed un- checked into
the Castro - Williams Debris Basin, and into the Walnut Creek
Channel. Had the mud and debris flows not been captured in the
various project detention basins, the outcome could have been
disastrous for the neighborhoods of Moorpark that are downstream
of the Castro - Williams Debris basin, and along the Walnut Creek
Channel. After taking a post -storm inspection tour of the
various project sites, and seeing the amount of mud and debris
that was captured in the erosion control detention basins, it is
apparent that these developer constructed systems performed
their purpose very well and protected the City from additional
damage.
The Storm Aftermath
The storm continued through Tuesday, January 11, 2005, bringing
additional heavy periods of runoff down Happy Camp Canyon, and
more water and debris onto Los Angeles Avenue at the Villa Del
Arroyo Mobile Home Park, but with crews and equipment on around -
the -clock deployment, the conditions did not again appear to
threaten property. Other road closures that occurred Sunday in
and around the City of Moorpark included Championship Drive,
Walnut Canyon Road, and Grimes Canyon Road in the County area
just west of Moorpark City limits. At this time only Grimes
Canyon Road remains closed, with severe damage just north and
south of the intersection with Championship Drive. The storm
damage repair to roadways in Moorpark consisted largely of
clearing mud and debris, and isolated areas of undermining
behind the curb along Campus Park Drive. With the use of
contractors, rented trucks and heavy equipment, (and even one
welcome volunteer), the roadways in Moorpark were restored to
normal service by Wednesday, January 12, 2005. The Pardee,
William Lyon, and Toll Brothers developments graciously
volunteered to accept truck loads of mud and silt onto their
project sites, saving the City the time and added cost of
hauling to a landfill.
The Emergency Operations Center
Due to the "2005 Winter Storms," the Director of Emergency
Services (City Manager) proclaimed the existence of a local
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Honorable City Council
February 16, 2005
Page 6
emergency in the City of Moorpark on Sunday, January 9, 2005, at
10:30 a.m. To manage the City's emergency response, the City's
Emergency Operations Center (EOC) was activated from Sunday,
January 9, 2005, at 10:30 a.m. until Tuesday, January 11, 2005,
at 6:00 a.m.
Twenty -eight staf
plus Sheriff and
by City staff
intelligence, and
with the County
resources.
f participated in the City's EOC activation,
fire personnel. The major functions performed
were emergency protection, planning and
public information. City staff also interfaced
of Ventura EOC to share information and
Of the 28 City employees who staffed the EOC, 15 management
employees worked 196 hours, 11 competitive service employees
worked 204 hours, and 2 hourly employees worked 20 hours, for a
total of 420 hours. In addition, Videomax Productions provided
message coordination for the government access channel.
STAFF RECObIlINDATION
Direct staff as deemed appropriate.
ATTACHMENT:
1. Exhibit `A', Happy Camp Drainage report, by Ken Gilbert.
000036
MEMORANDUM
TO: Steven Kueny, City Manager
.i
FROM: Ken Gilbert, Director of Public Works
DATE: January 31, 2005
SUBJECT: Happy Camp Drainage
Background
As you know, on January 9, 10 & 11 severe storms, combined with bare the slopes created by the
October 2003 fire, created high storm flows out of Happy Camp Canyon. These flows, which were
heavily ladened with rocks, gavel, silt, tree stumps and other debris, overwhelmed the Happy Camp
Channel, threatened the homes on Cambridge Street, flowed down Campus Park Drive.
Staff has been advised by the Ventura County Watershed Protection District [ "District "] that the
Happy Camp Canyon watershed was very hard hit by this storm. While storm flows measured at
Madera Road were only 2,500 cfs (cubic feet per second), those measured at Hitch Boulevard were
over 10,000 cfs. This means that most of the storm flows came out of the tributaries north of
Moorpark, including the Happy Camp Canyon watershed. In fact rain gages in the Happy Camp
basin measured over fifteen inches (15 ") of rain during the three day event (over 8" in one twenty -
four (24) hour period). The District advised us that this intensity of rainfall equates to a 200 year
storm event.
The District has a maintenance road (Maintenance Road) located just north of the houses on
Cambridge Avenue. The Maintenance Road runs from Campus Park Drive westerly to the
improved Happy Camp Channel located west of Westwood Street. There is also a dirt channel
[ "Dirt Channel "], located upstream of the improved trapezoidal channel, running east -west along the
north side of the Maintenance Road (see attached photo). The high storm flows damaged the
Maintenance Road. In addition, when the Dirt Channel "silted -up ", the storm flows traveled in a
southeasterly direction to the Golf Course entrance at the north end of Campus Park Drive.
During the storm event, the District used bulldozers to remove silt from the Dirt Channel. This silt
removal operation resulted in the creation of a berm, running east -west, along the north side of the
Maintenance Road [ "South Berm "]. More current actions with regard to this South Berm is
discussed below.
During this silt removal operation, the City asked the District to also construct a berm (running
north- south) north of the Dirt Channel [ "North Berm "], to redirect storm flows away from Campus
Park Drive (to the southeast) and back toward the Happy Camp Channel (to the southwest). The
District advised the City that the District could not work in areas outside of the limits of their
facilities.
The owner of the area north of the District's facilities is the General Services Agency of the County
of Ventura (GSA). We contacted GSA and they agreed to pay a contractor (contacted by the City
{Sharma}) to construct the North Berm. Although a portion of the North Berm was constructed, it is
believed that additional work needs to be done in this area to provide better protection for Campus
Park Drive.
HappyCar!p_0501
00003
Happy Camp Drainage
January 31, 200-5
Pane 2
Discussion
A. Meeting with County Parks Department
Loren Blair of GSA arranged for Theresa Lubin and Andy Oshida, of the County Parks
Department, to meet me at the site. That meeting occurred this morning.
B. District Restoration Efforts
During this site visit we noticed that a contractor, working for the District, was removing material
from the Dirt Channel and was modifying the South Berm to a lower (4' — 5') height. We
happened to encounter Ernie Bravo, from the District, who confirmed that the South Berm, as
modified, was going to be left in place to provide protection for the Maintenance Road and the
houses south of the Maintenance Road. He also confirmed that it was not the District's intent to
extend the Dirt Channel all the way to the golf course road to provide drainage from the dip in
the road located just north of the gate. He said they could not do that because, again, the area
between the end of the Dirt Channel and the golf course road was not within the District's
property. Resolution of this problem is discussed later in this report.
C. Current Golf Course Restoration Efforts
During this site visit we also noticed that a contractor, working for the golf course, was removing
silt and debris from areas which are part of the golf course. It is assumed that this work will not
disturb the North Berm. I will follow -up to confirm this to be true.
D. Roadway Drainage
Ms. Lubin said that it was her intent to have the golf course contractor construct a swale from the
dip in the golf course entry road to the Dirt Channel, to provide positive drainage for the road
way and the north -south roadside swale which extends to the north along the west side of the
golf course roadway.
E. Eastside Slope
It should be noted that some of the mud flow on Campus Park Drive came from a slide on the
slope located just east of the golf course entrance. The slope remains exposed and subject to
further erosion. It is my intent to see if the County NPDES people (not the District NPDES
people) can get the owner of that property to repair and restore that slope.
Happyr_a:np 0501
Happy Camp Drainage
January 31, 2005
Page 3
F. Long Term Protection
At the aforementioned site meeting, I voiced my concerns that the "ultimate" plans for the Golf
Course restoration should include efforts to preserve, protect, extend and enhance the North
Berm, so that a measure of protection can be provided for Campus Park Drive. Mr. Oshida said
that they would include those concerns in their discussions and would work toward a solution
which addressed those concerns. I expect to hear from him later as to further development of
the final design for the restoration of the golf course and the area south of the golf course.
G. Future Emergency Response
Even without a "bullet- proof' North Berm to protect Campus Park Drive, I do not expect that
another major storm will cause the degree of damage we recently experienced. With the
knowledge learned from this recent event, I expect that, in the event of a major storm, the
District will deploy bulldozers to keep the silt from building up in the Dirt Channel, which will keep
the flow running toward the Happy Camp Channel.
H. Maior Re- Grading
I believe I had talked to you, Brad Miller and others about my idea for major re- grading of the
area just north of the Cambridge homes and Campus Park Drive, to create a "bowl" effect to
retain mud flows which exceed the capacity of the Dirt Channel. Although I mentioned this
concept to Mr. Oshida, I doubt that they will be giving this idea serious consideration.
I. Conclusions
In my opinion, the construction of the golf course had no bearing on the behavior of the recent
storm run -off. The reasons for this conclusion are:
• There are no siltation / debris basins in this watershed — only a Dirt Channel.
• The watercourse (dry stream) just upstream of the Dirt Ditch has very little capacity.
• The area just upstream of the Dirt Channel is very flat (with or without a golf course).
• This area "silted -up" and the storm /silt/debris flows made their way to Campus Park Drive.
It should also be noted that this was a 200 year storm event in the Happy Camp watershed — a
watershed which sustained a recent "burn -off'. Typically, agencies do not design facilities to
"handle" such events.
J. Follow -up
It is my intent to send a letter to the District asking them to fund (as a high priority) a study to
determine the scope of flood control measures and facilities needed in the Happy Camp basin.
cc: Brad Miller, City Engineer
HappyCamp 0501
000039
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