HomeMy WebLinkAbout41- City Administrator's Office WN
CITY OF SAN BERNARDINO REQUEST FOR COUNCIL ACTION
From: Fred Wilson, City Administrator Subject: Discussion relative to disaster
preparedness plans to deal with
Dept: City Administrator ' s Office "El Nino" conditions anticipated
0
t
i ,�,tduring fall/winter 1997-98
Date: September 30, 1997 yY
� I iV r
Synopsis of Previous Council action:
9/15/97 - Motion to continue this item to 10/6/97.
Recommended motion:
Receive and file.
Signature
Contact person: Frets W; 1 son Phone: x5122
Supporting data attached: Ward: all
FUNDING REQUIREMENTS: Amount: N/A
Source: (Acct. No.)
(Acct. Description)
Finance:
Council Notes:
/(J 4/91
75-0262 Ononrin Itom IVn 411j
Staff Report
Preparations are underway for the El Nino weather patterns that are predicted for this
winter. The purpose of this staff report is to detail these preparations for the information
of the Mayor and Council, as well as the public.
El Nino Predictions
On September 29, 1997, the San Bernardino Fire Department Disaster Preparedness
Division hosted a meeting of the area organizations involved in El Nino preparations.
Those in attendance included staff from San Bernardino Water, Public Services, Public
Works, Parks, Recreation and Community Services, Police, Fire, Risk Management,
Animal Control, CATV, County Flood Control District, San Bernardino National Forest,
San Bernardino County Office of Emergency Services, San Bernardino City Schools, Cal
State San Bernardino Public Safety,National Weather Service, Salvation Army, and the
Red Cross. A copy of the meeting informational packet is attached(Attachment A).
At this meeting, Mark Meady of the National Weather Service (NWS) explained that El
Nino is caused by a disruption of the oceanic atmosphere the tropical Pacific Ocean.
Higher water temperatures cause winter storms to take a more southerly route than
normal. Also, higher sea surface temperatures bring more rain than would usually be
expected from winter storms.
The NWS is predicting rainfall to be 200-300% above normal from October through
March. While El Nino conditions occur every few years,NWS believes that the strength
of this El Nino is unprecedented.
The following chart shows the rainfall predictions for San Bernardino County for October
through March:
Normal Outlook
Valley 10 - 12" 15 - 20"
Mountains 30 - 45" 45 - 60"
Desert 7 - 9.5 10 - 15"
The heavy rains are especially dangerous in the areas recently burned in the Hemlock,
Mill, and City Creek fires.
Preparations by Outside Agencies
The National Forest Service has been conducting analysis of the impacts of higher rainfall
upon burn areas. In these areas of high-intensity burns, the soils will not be able to hold
substantial amounts of water, and National Forest Service expects increases in soil losses
in these areas.
The County Flood Control District prepares for storm season each year by cleaning storm
channels and debris basins in the foothill areas. The District reports that the debris basins
are now clean and ready for the coming rains. Special preparations are being made to
handle the debris flows anticipated into the Sand Canyon and Little Sand Canyon debris
basins as a result of the recent fires. A telemetric rain gauge is being placed at the
Hemlock fire site so that rainfall can be monitored.
City Preparations
Public Services has inventoried its signs and barricades that are used to mark flooded areas
and direct traffic. Additional signs and barricades have been ordered and are expected to
be received by November 1.
A new sandbagging machine has been field tested by Public Services. Two machines are
on order and will be delivered by November 1. Each is capable of filling 3600 sandbags
per hour, even with wet sand. The machines are mobile and will be used wherever they
may be needed. Four thousand(4000) filled sandbags have been stockpiled at fire stations
for use by city crews, and an additional number of bags are available to residents at Blair,
Wildwood, and Seccombe Lake parks. The city has 250,000 empty sandbags in inventory
that can also be filled.
Public Services street maintenance crews have been diverted from other duties to clean
especially vulnerable catchbasins. A Public Works contractor is also removing debris from
catchbasins and cleaning culverts.
Animal Control is preparing to assist residents who may be required to evacuate their
homes. Because the Animal Shelter is located in a flood plain, the division is also locating
an alternate shelter site that could be used in an emergency.
The Police Department has plans to call out staff as needed to address emergency
situations. Patrol cars will also be policing traditional flood-prone areas. The Fire
Department will continue to play the lead role in the coordination of city resources. A
basic swift water rescue training is planned for fire staff on November 1.
The Fire Department is coordinating a public education effort that is centered around the
development of an video that will be broadcast on Channel 3. The video will include
information on resources available to the community, including other agencies such as the
Red Cross.
Recommendations
It is recommended that the Council receive and file this report.
J
EL NINO
PREPAREDNESS FORUM
f
/ a
a � d
SAN BERNARDINO CITY HALL
SEPTEMBER 29, 1997
1000 - 1200
ti
El Nino Disaster Preparedness Program
City of San Bernardino City Hall
300 N. "D" Street
Management Information Center - Sixth Floor
September 29, 1997 10:00 am to 12:00 noon
AGENDA
1000 - 1005 Welcome and Introduction Fire Department
1005-1025 El Nino Predictions National Weather Service
1025-1040 Seven Oaks Dam/Santa Ana River Flooding Army Corps of Engineers
1040-1050 Hemlock Fire Watershed Response US Forest Service
1050-1105 Status of Flood Control Systems & Resources County Flood Control
1105-1135 Status of City Preparations & Resources City Departments
1135-1145 Community Agency Preparations & Resources Community Agencies
1145-1200 Identification of Follow-on Actions Fire Department
e
.� SAN BERNARDINO PRECIPITATION DATA
Hampshire El Nino El Nino
Month Normal 1980 1982 1983 1991 1992
Jan 3.49 9.18 4.69 5.41 2.45 1.86
Feb 2.77 12.03 2.01 4.9 4.43 5.51
Mar 2.5 5.3 6.01 7.46 8.23 6.07
Apr 1.32 1.64 3.22 0.01 0.19
May 0.54 0.53 0.05 0.02 0.05
Jun 0.08 0.04 0 0 0
Jul 0.04 0 0 0 0.23
Aug 0.13 0.02 3.72 0 0
Sep 0.49 1.09 0.68 0.07 0
Oct 0.52 0.24 2.15 0.63 1.13
Nov 1.62 4.35 3.55 0.16 0
Dec 2.18 2.31 3.23 1.84 5.06
Annual 15.68 22.93 34.37 17.84 20.1
Historical Notes
1862 Jan 22 Greatest flood of record, 3 x 1938; 6 x 1980
1884 12 inches in Feb; 10 inches in Mar
1891 17 inches at Big Bear and 4.53 inches at San Bernardino in 24 hours
1916 Two six day storms; peaked Jan 17 and 28
1938 182,000 acres inundated in Riverside and San Bernardino Counties
1969 Late Jan and early Feb storms dumped 16 inches in valleys, 60 inches in mountains
1976 3.5 inches of rain in 30 minutes in Sep; Moved 10 Ton boulders
1980 Six storms in 10 days in Mid-Feb
16.0 FLOODING
INTRODUCTION
Flooding represents a potential hazard to the population and buildings of a city and, as
such, is a concern of the State-mandated public safety element. Additionally, state law
requires that areas subject to flooding be addressed as a component of the land use ele-
ment. This section of the plan addresses the risks of flooding due to the natural physi-
ography, rainfall, and runoff of the City.
BACKGROUND DATA AND ANALYSES
The 100-year floodplain within the planning area is depicted on Figure 62, as by the
Federal Emergency Management Agency Flood Insurance Rate maps. The 100-year
floodplain, for the most part, is confined to storm channels, debris basins, and between
levees. A few areas, including the Base Line Street and Sterling Avenue area, Mountain
View Avenue and Electric Avenue area, and south of Redlands Boulevard, east of
Hunts Lane, are identified as low areas within the 100-year floodplain. A description of
existing flood control facilities is presented in the Utilities Element, Subsection "C" of
Section 7.0 of this Plan.
The City of San Bernardino has established design criteria for both major and local
drains within the City. Major drains are systems using 36-inch diameter, or larger pipes
(or equivalent channels) and are identified on the comprehensive storm drain plans, or
are of regional significance by providing additional capacity for off-site flows of specific
development projects. Local drains are systems using less than 36-inch diameter con-
duits, and provide drainage for specific projects.
Major drains in developed areas shall have a pipeline capacity to contain 25-year storm
flows provided that the 50-year storm flows can be contained within the curbed portion
of the street and the 100-year storm flows can be contained within the street right-of
way. Major drains in foothill areas where downstream systems are lacking and street
systems are not present, shall be designed to convey 100-year flows within a pipe or
channel.
Local drains in developed areas shall have a pipeline capacity to contain 10-year storm
flows provided that the 50-year storm flows can be contained within the curbed portion
of the street and the 100-year storm flows can be contained within the street right-of-
way. Local drains in foothill areas where downstream systems are lacking and street
systems are not present, shall be designed to convey 25-year storm flows.
Basements and underground utility vaults experience flooding in areas between the
Santa Ana River and downtown due to the high groundwater table.
16-1
c $ I
CD
4)
� N
CU a
Z v c ca —
(D M
Q _
c o —
J
o
CL
fC N Q �z
m
O (D m c
O Q E c Z
J o L11 N I O
tL O ? m c
CM s w _ 0 o ,--' O
co w LL ° !�,' CL
w >- �; � O
U V
0 C p6� I X06 U
p Q 1!� I I eny iaQ\ I
I
LL � �---� f'L/i L—I tl O i
I '
`L( I / J I ony wild ---I LS eweQely
U
Jr—
I tiFn IL Z
Uj
I \ o e
------- Pny ellolalN I
! L I+ rl I L
I I— � Y ulllelS ;3?.ua II
Ir
i
I \
world or
m any umell
:...
J
' / a
lent'uowaA•Iry
r -J
I / L
---- .D•° 1 an p OU
I -- - 1 slel Y 4 et'
-- c S S � ,
�5
I j l I � i i '•�, I I
q
I G'\oo \ "'G • '-Tr> •I— 1---I IS leddad 1
— ° m
!
I
l —
) :%� is�?f�ts7>;.::•
L
16-2
f
Sar Bernardino County Flood Control District
District facilities - Areas of Concern Within San Bernardino
East Rialto Storm Drain- Inadequate for Qloc, tuul duti-morating condition of reinforced concrete
and gunite channel.
Penner,Mill.and Randall Basins -Inadequate volume l:)r attenuation of 100-year storm event.
Spillway and outlet facility improvements are needed,especially at Randall Basin(spillway
needed).
Cajon Creek- nip crossing;at Institution Road is routinely impacted by storm events. Railroad
embankment and levee(s)upstream of Devi) Creek diversion channel have been undermined in
recent storm events.
L3nlc Creek - Levee improvements and Corps of Engineers basin and channel improvements
provide significant flood protection. No apparent areas of concern.
Lower Warm Creck- Basin and channel improvements provide significant flood protection. No
apparent areas of concern.
t)cvil Creek-upper system,diversion channel and basin appear adequate. Devil creek Chatulel
from College Parkway to Little Mountain Dean contains dips crossings at numerous street
location,;.
Little Mountain C'hannQl at Ncwma,,k - Dip crossing at Newmark Avenue experiences flooding
in storm events.
MacQuiddy and Brush Canyon Basins- Sturm flows lrozn basin spillways are directed to
Electric and Mountain.View Avenues respectively.
Twin Creek - Culvert crossing at fortieth Strcet has experienced flooding in recent storms.
Potential for erosion and undermining of road base.
Dailey Basin and Dcl Rosa Channel - Channel is inadequate for Q,0r and may experience
significant erosion. Basin volume is inadequate lur capture of debris generated from a major
storm event.
Little Sand Creek Basin and Chana!�J- Debris Basin is inadequate. Channel crossing at roothiif
Drive may experience overflow condition with vignificant debris production from the burned
watershed. Outlet channel from Lcmon Basin is inadequate to convey storm -lows from a major
event.
Sand Cannon Basin and Channel- Debris basin is inadequa w. Channel crossing at Lynwood
Drivc may experience overflow condition with significant debris production from the burned
watershed.
Sina l Canyon Basin and CiianLncl -Debris basin is inadequate for major storm events. Diversion
channel from Small Canyon Basin to Dynamite Basin is guvdte construction and has deteriorated
with age_ Overflow!mm cltumel to areas to the south may occur in larger storni events,
[?pner Warm Creek- Rail and wire revetment channel is subject to erosion and degradation
during larger storm events.
City Creek -Channel is subject to erasion and degradation, especially in those reaches not
maintained by the District(along Third Street at the Norton Base).
Mission - Channel and street crossings are inadequate to convey storm flows from larger
storm events, especially at Tippecanoe Street.
Public Works Department Contract
Cleaning of catch basins is to be performed at the following
locations, and as designated by the City Engineer:
1. PALM AVENUE BETWEEN WASHINGTON STREET AND CABLE CREEK
2 . NORTHPARK BLVD BETWEEN UNIVERSITY PKWY AND ORANGE DRIVE
3 . "I" STREET NORTH OF NORTHPARK BOULEVARD
4 . NORTH "E" STREET NORTH OF NORTHPARK BOULEVARD
5. "F" STREET NORTH OF NORTHPARK BOULEVARD
6. MEDICAL CENTER DRIVE AND HIGHLAND AVENUE
7 . 16TH ST BETWEEN PENNSYLVANIA AVE AND MASSARRO ST
8 . GILBERT STREET BETWEEN WATERMAN AVENUE AND CANYON ROAD
9 . BASE LINE STREET BETWEEN MYRTLE DRIVE AND CANYON ROAD
10. HOSPITALITY IN BETWEEN SAN TIMOTEO CREEK AND CARNEGIE DR
11. CARNEGIE DRIVE NORTH OF VANDERBILT WAY
12 . HOSPITALITY LANE NORTH OF HARRIMAN PLACE
13 . HARRIMAN PLACE EAST OF GAGE CANAL
14 . ORCHARD DRIVE BETWEEN ROSEWOOD DRIVE AND LAURELWOOD DRIVE
15. 2ND STREET AND "E" STREET
16. N.W. CORNER OF 3RD STREET AND ARROWHEAD AVENUE
Cleaning of parkway culverts is to be performed at the
following locations and as designated by the City Engineer:
STREET INTERSECTIONS
1. BASE LINE STREET AND "E" STREET
2 . BASE LINE STREET AND "D" STREET
3 . BASE LINE STREET AND ARROWHEAD AVENUE
4 . BASE LINE STREET AND MT. VIEW AVENUE
5. BASE LINE STREET AND SIERRA WAY
6. BASE LINE STREET AND WATERMAN AVENUE
Public Services Department
Locations to be inspected during heavy rains
1. Quail Court
2. Bonita Vista at Hacienda
3. 40'' West of Harrison
4. Piedmont West of Manzanita
5. Lynwood Dr. west of Victoria at flood channel
6. West of Yuma dr. at Flood channel behind Indian Bingo
7. Citrus at Palmcrest
8. Denair at Highland
9. Love Ln. west of Orange
10. Brush Canyon debris basin near Sepulveda
11. 'H' Street north of Kendall at County Flood channel
12. Mountain View at Lugonia
13. Evans St. at 'I'
14. Chestnut at Washington
15. Chestnut at Belmont
16. Santa Ana River Crossings
17. City Creek
18. Warm Creek
Water Department Areas of Concern
1 . Daley Canyon. Water service to homes in Daley Pressure
System (Approx 500 homes ) .
2. Devil Canyon. Water service to homes and State facilities.
3 . Verdemont Area. Water service to homes northeast of
Belmont Avenue (Approx 300 homes) .
CRITICAL FACILITIES SUBJECT TO FLOODING
1. City Water Reclamation Plant
2. City Animal Control
3. S.B. & Riverside Counties Blood Bank
4. Inland Center Mall
5. Hospitality Lane businesses
6. Sewage Disposal Plant south of Santa Ana River near Alabama
7. San Bernardino IAP runway
8. Edison substation near City Water Reclamation
9. Edison power plant near Mt. View south of Santa Ana River
10. County Complex on Rialto
11. Burbank School on Mill near Warm Creek
12. Fire Station#9
13. County Medical Complex
14. Fairfax School on Pacific
15. Pacific High School
16. Sewage disposal near Arrowhead Springs
17. Campus Crusade Center at Arrowhead Springs
18. Richardson Prep High School on Mill, west of freeway
19. Edison substation near Waterman and Rialto
20. San Manuel bingo parlor
21. South"E" Street businesses
22. National Orange Show
23. Riley School at 13th and "G"
24. County Government complex
25. Fire Station#1
SOILS REPORT
HEMLOCK.FIRE - JULY 1997 Z
NORM AMBOS
SOIL SCIENTIST ?b SZ
TONTO NATIONAL FOREST
I. Resource Condition Assessment
A. Initial Concerns: Threat to human life and property on roads and
other public access points down stream of burned areas, degradation of
water quality and fish habitat, and loss of soil productivity due to
soil eroding from the burned area were identified as issues prior to
conducting the BAER survey.
B. Findings of The On The Ground Survey
1. Summary of Findings:
The results of four days of field reconnaissance and watershed
response mapping of 3750 acres within the fire boundary gave the
following results:
1695 acres (45 percent) -- high watershed response
180 acres ( 5 percent) -- moderate watershed response
1515 acres (40 percent) -- low watershed response
360 acres (10 percent) -- unburned
The highest concentration of areas with a high watershed response are
in Little Sand Canyon and Sand Canyon.
Watershed response is a measure of how the watershed will react to
precipitation following a fire based on characteristics of the
watershed and changes on the watershed brought about by the fire.
Burn intensity is a measure of the degree in change of a watershed
brought about by the fire. It is related to such things as reductions
in infiltration brought about be water repellent soils or increased
erosion caused by reduced ground cover.
Areas mapped with a high watershed response had soils with high burn
intensities, or a mixture of moderate and high intensities, had low
ground cover, and, for the most part, occurred on steep slopes. Areas
with a moderate watershed response had moderate or low to moderate
burn intensities and higher cover than areas with high watershed
response. Areas with low watershed responses had low or moderate burn
intensities but maintained fairly high ground covers.
r2. Additional Information:
Most of the slopes within the burned area are steep, averaging between
45 and 65 percent. The following table shows the slope data:
Slope Acres o of Area
6-15 31 0.8
16-25 154 4.1
26-35 346 9.3
36-45 540 14.5
46-55 751 20.1
56-65 954 25.5
66-75 747 20.0
76-85 136 3.6
86+ 78 2.1
The major soils found within the burned area are Typic and Lithic
Xerorthents and occupy more than 90 percent of the area (Soil Survey
s of Sand Bernardino National Forest Area, California) . They are
shallow, coarse textured soils, with moderately rapid permeability.
These soils have a high hazard for sheet and rill erosion and are
subject to gully erosion and mast wasting. An estimate of erosion
based on the Universal Soil Loss Equation (USLE) shows a pre-burn rate
of about 5 tons/acre/year verses a post-burn erosion rate of 23
tons/acre/year. Areas of rock outcrop commonly occur with these
soils.
Although a large increase in soil loss is expected, treatments to
prevent erosion would be extremely expensive compared to the value of
the soil, therefore no treatment to prevent soil loss is proposed.
The geology of the area is dominated by gneiss, schist, and quartz
monzonite. Active faults run through the burn. During field
reconnaissance, numerous head walls and slides were observed. The area
appears to be geologically unstable.
II. Emergency Determination
It has been determine that there is a fire-caused emergency for threats to
human life and property. There is an excessive watershed response in the
upper portions of Sand Canyon and Little Sand Canyon because of the large
areas with moderated to high burn intensities, highly erosive soils, and
unstable slopes. There is a definite risk of floods and debris flows in
these canyons and downstream where they pass through private land. The
risk is greatest at the bridge crossings at Foothill Boulevard and Lynwood
Drive and where the channels are constricted before they enter the debris
basins.
A watershed of lesser concern occurs on the San Manuel Indian Reservation.
This watershed of 230 acres (Labeled watershed "A" on the watershed map.)
originates on the Reservation and empties onto private land downstream.
one hundred-nineteen acres of this watershed burned, all at low intensity.
only a small increase in peak flow is expected from this watershed but it
is a concern because of downstream property.
III. Treatments to Mitigate the Emergency
Treatments on National Forest lands to mitigate flood damage from the
emergency were considered but rejected. Because of steep slopes grass
seeding would not be effective and treatments such as straw wattles or
contour terraces would be expensive, difficult and dangerous to install and
would only be marginally effective. Since only- a small portion of the City
Creek watershed burned and the burn intensity was low, no degradation in
water quality or fish habitat in the creek is expected. Some type of
terrace work, however, may be effective on the olive groves on private
land. Flood warning signs installed on Forest, Reservation, and private
lands would be appropriate to mitigate risk to human life.
IV. Other Recommendations
e
- The debris basins should be evaluated to determine if they are capable
of storing the predicted volume of sediments. The upper basins should
be cleaned out to increase capacity. The channels and bridges above
the lower debris basins should be evaluated to determine if they can
pass expected flows. During periods of high rainfall, stepped up
patrols should be made to warn people of the danger of flash floods.
The Forest should monitor the burn for watershed recovery. They
should establish photo points and vegetation plots to assess recovery
of vegetation and ground cover.
y. References
U.S.D.A. Forest Service and Soil Conservation Service. Soil Survey of San
Bernardino National Forest Area, California.
HYDROLOGY ,S700 (
Hemlock Fire July, 1997
Randy Gould
Hydrologist
Sequoia National Forest, Cannell Meadow/Greenhorn Districts
I. Resource Condition Assessment
A. Initial Concerns
1) . Risk of increased runoff and sedimentation resulting in downstream
impacts to life and property. Risk of loss of downstream iprovements,
roads and bridges, to flooding and possible debris flows.
2) . Effects of watershed responses to fire that could degrade water
quality, riparian areas, and aquatic habitat.
B. Findings of the Ground Survey
The majority of the 3750 acre Hemlock Fire burned in the Sand Creek
Watershed, (WRC Watershed Number 1807020312) . Approximately 395 acres
burned into the City Creek Watershed, (WRC Watershed Number 1807020311)
The Sand Creek Watershed includes two major sub-drainages, Sand Canyon and
Little Sand Canyon. Three smaller face drainages, designated A, B, and C
for this report, are included in the burned area, ( see attached map)
Drainage area, acres burned, and watershed response in each affected
drainage are summarized in Table I.
Little Sand and Sand Canyon sustained the highest amount of burned acres.
The two drainages contain all the acres designated as high watershed
response. These drainages will have increased surface runoff, soil erosion
and sediment delivery to the streams. Because of the geomorphology of the
area, Sand Canyon and Little Sand Canyon could experience mud and debris
flows if a large storm event were to occur. Drainages A, B, and C will
have a low watershed response and increases in peak flows should be
minimal. Debris basins at the bottom of drainage C should hold any excess
runoff or debris flows that occur within the drainage. The burned area in
the City Creek drainage will have a low watershed response and minimal
effect to the watershed are expected.
On-the-ground survey of Sand Canyon showed the riparian vegetation in the
lower portin of the main stem to be intact. The headwaters of Sand Canyon
were burned with little vegetation remaining in the ephemeral channels.
Slopes in Sand Canyon are very steep, averaging 55% to 75%. Dry ravel had
started and there were indications of previous slumps and mass wasting on
the -slopes. The main channel is downcut in the bottom of the drainage and
becomes bedrock controlled in the upper drainage.
At the mouth of the canyon, the stream flows into a small debris basin.
The channel below the debris basin has been straightened and is full of
rocks and brush where it flows past the Reservation casino parking lot.
The channel proceeds past the parking lot and crosses under Lynwood Street
and down to a large debris basin. The bridge crossing on Lynwood, houses
adjacent to the channel, and the Casino parking lot will be at risk if a
large storm event occurs.
The survey of Little Sand Canyon showed high intensity burn in the riparian
vegetation in the lower part of the burn. The channel is downcut
approximately 10 to 15 feet in the lower end of the basin. A heavy
sediment load was observed moving through the channel at this point.
Farther up the drainage the channel becomes bedrock controlled in steep
V-shaped canyons. Slopes of up to 85% were observed. The upper portion of
the watershed has a large area that will have a high watershed response.
The drainage shows evidence of prior slumping and soil creep.
At the mouth of the drainage, the stream flows into a small debris basin.
The channel proceeds out of the debris basin and flows down a straightened
channel under Foothills Drive into a large percolation basin. If a major
storm event were to occur, the bridge could be plugged or taken out by a
debris flow.
Debris flows are known to occur in the area of the Hemlock Fire. The
Harrison Canyon Watershed which is approximately 1.5 miles west of Little
Sand Canyon had a major event occur in 1980. Approximately 94% of Harrison
Canyon watershed burned during the Daley Fire in September of 1979. The
estimated debris potential was calculated at 58, 000 cubic yards. Four
storm events in January and February 1980 produced approximately 255,00
cubic yards of debris from the 384 acre drainage. Data from the San
Bernadino County Floo Control District shows the actual debris production
was about five times _treater than planned for. Data from other areas along
the southern and sout.1-aest facing slopes of the San Gabriel and San
Bernadino Mountains s,Lows similar production of sediment following a fire
in areas exposed to high intensity rainfall (Slossen et al, 1989) .
Peak flows in the City Creek, "A", "B", and "C" drainages will not increase
significantly, (see Tale II) . Peak flow in Sand Canyon and Little Sand
Canyon could have sig;iificant peak flow increases. The Harrison Canyon
debris flows had bulking of 2 to 5 times the estimated peak flows, (Slossen
et al, 1989) . This me"ns with debris added to peak flows, flow could be 2
to 5 time greater that, estimated, (Table II) .
II. Emergency Determination
Based upon observatio:i, collected data, and historic data of the area, an
emergency situation e::ist to life and property below the Sand Canyon and
Little Sand Canyon drainages. There is the possibility of debris flows
•simi'iar to flows that occurred in Harrison Canyon in 1980, (Slosson et al,
1989) .
III. Treatments to Mitigate the Emergency
Treatment of National Forest Land is not practicable. Steep slopes and
high gradient channels make any .hillslope or channel treatment
impracticable in the upper portions of the two drainages. To reduce risk
on National Forest land, signs should be posted warning of possible
flooding in the drainages and the potential of debris falling on roads
located within the burn.
IV. Discussion/Summary/Recommendations
The following are treatments that can be done off Forest Service ground to
help mitigate the emergency.
1. Clean and enlarge upper debris basins in Sand and Little Sand Canyon.
2. Monitor and patrol the Casino parking lot during rain events.
3 . Post flood warning signs on all drainages in the burn area.
4. The city and county flood control should clean all drainage channels'
going into debris basins and monitor all road crossings during storm
events.
5. The channels flowing out of the upper debris basins in Sand Canyon and
Little Sand Canyon should be evaluated by engineers to determine if the
channels and bridge can carry a major event, similar to the event that
occurred in Harrison Canyon in 1980 (Slosson, et al 1989) .
Slosson, J.E. , Havens, G.W. . Shuirman, G. , and Slossen, T. L. 1989. Harrison
Canyon Debris Flows Of 1980, Publications of the Inland Geological Society,
Volume 2:285-298.
Table I
Drainage
Total Acres and Percentage Watershed Total Acres Response Burned
ILow % IMod % I High Ivnburned % IAcres %
Sand Cannon 1 2003 1 285 14g ( 86 4o 1 1232--62t 1 401--20% 11603--80t
1 .. 178--
Little Sand I 954 1 219--23t l 94-_-10%L 463--49k 19t 1 776 81t
A I 230 1 11952% ( 0 1 0 1 111- 48'k 119--52t
B 1 160 I 37 23� 1 0 I 0 1 123- 77t I 37 23%
3�
C _L 575 J( 460 80% ( 0 I 0 1 115--20*- 460--80t
City Creek 112422 1 395--03%- ( 0 I 0 112027 97% 1 395 03'k
Table II
Drainage Design Flow Adjusted Design Flow Peak Flows
pre fire post fire with bulking
Little Sand ( 690 cfs ( 1063 cfs ( 2675 cfs
Sand Canyon ( 1312 cfs ( 2122 cfs ( 5305cfs
"A„ ( 200 cfs ( 216 cfs ( N/A
„Bit ( 146 cfs ( 151 cfs ( N/A
licit ( 445 cfs ( 498 cfs ( N/A
City Creek ( 6448 cfs ( 6476 cfs ( N/A
The design flow is calculated using the 100 year peak discharge pre-fire.
Adjusted Design flow is calculated on 100 year peak discharge adjusted to
reflect watershed response after the fire. Peak flows, adjusted for bulking,
were determined using information from (Slossen et al 1989) , L.A. County 50
Year Design for Potential Debris, Hydrology / Sedimentation Manual, and
personal communication with M. McCorison, former Forest Hydrologist on Angles
National Forest.
FLOOD PREPARATION CHECKLIST
NO. TASKS ACTION AGENCIES
1. Identify flood prone areas; coord with all Water, Pub Svs, Public Works
2. Identify flood warning signs and monitor locations Water, Pub Svs, Public Works
3. Identify watch staff, inform individuals All
4. Identify on-call staff and contact points; inform All
individuals
5. Identify required emergency supplies, equipment All
and vehicles & any prepositioning requirements
6. Identify any City and/or critical facilities and Disaster Preparedness
resources within flood prone areas; coord. with
affected agencies
7. Identify critical coordinating agencies and 24-hour All
points of contact; make initial contact
8. Identify any shelter requirements and shelter Parks & Rec, ARC, Schools
locations; coord. with affected agencies
9. Identify emergency public information, media All
briefing requirements
10. Identify any emergency funds requirements; All
coord. with Finance
11. Identify communications requirements; coord. All
with Telecommunications and MIS
12. Identify volunteer requirements; coordinate All
with Personnel
13. Identify and clear any clogged storm drains Pub Svs, Pub Works, Water
and/or channels
14. Identify possible ripple effects and mitigation
options; coordinate with all
a. Transportation outages PD, Pub Svs, FD, Pub Works
b. Power outages Water/Edison/Fac Mgmt
c. Gas outages Water/SC Gas/Fac Mgmt
d. Water outages Water/Fac Mgmt
e. Water contamination Co Health/Fac Mgmt
f. Sewer overflows Pub Svs
g. Health concerns Co Health/FD
15. Identify evacuation considerations
a. Criteria for implementing PD
b. Mandatory vs. Voluntary Policy Group
c. Notification procedures, requirements PD/PIO
d. Transportation Garage/Schools
e. Cordon control - ingress/egress PD
f. Security for evacuation areas PD
g. Evacuating handicapped personnel PD/FD
16. Identify policy considerations; coordinate All
with Policy Group e.g.
a. Overtime pay
b. Contingency fund expenditures
c. Curfews
d. Protecting private vs. public property
e. Mandatory vs. voluntary evacuation
f. Issuing City owned emergency supplies
e.g. sandbags, shovels, sand
g. Proclaiming local emergency
h. Using volunteers and/or mutual aid
17. Identify rescue considerations Fire
a. Special equipment
b. Trained personnel
c. Coordinating agencies
I
CITY OF SAN BERNARDINO - REQUEST FOR COUNCIL ACTION
From: Councilman David Oberhelman, Fourth Ward Subject: Disaster Preparedness Plans
for "El Nino"
Dept: Council Office r
Date: September 8, 1997 ORIGhAr
Synopsis of Previous Council Action:
SEP 0 8 199