Transcript Flood Warning and Low Water Crossing Warning Systems

ALERT Low Water Crossing
Warning Systems
Produced by
Rand Allan, Associate Meteorologist
County of San Diego Flood Control
The Need for Low Water
Crossing Warning Systems
 Flooding
claims scores of lives each year
 Each foot of water rise displaces up to
1500 lbs of vehicle weight
 Lateral force of a flooding stream can
place over 500 lbs of force on a vehicle
 Small vehicles and pedestrians can be
swept off the road in as little as 6”-12”
of water
 Flood waters can hide washed-out
Low Water Crossing
Warning Devices
Three
Examples
Stand-Alone System
Warning light
•Relatively
activates when
inexpensive,
cost
water$1,000
over the
road
about
-$2,000
 Good for remote,
•Can
be built
inlightly
traveled
house
areas with little
accident
•For
abouthistory
$2,500
more
they can
be is

However,
there
modified
for ALERT
no notification
radio
transmission
given
to authorities

Warning Flasher Scottsdale, AZ
Automated ALERT Signals
can phone
•Station
Under control
of
ALERT Flasher Harmony Grove, CA
agencies
toALERT
warn of
flood events
system
 As water first flows
over road,can
lights
flash
•Agencies
phone
yellow;tosign
use
station
get says
current
caution when crossing
conditions
 As water reaches 6”
•Cost
is moderate,
about
over road,
lights flash
$15,000
to changes
$20,000 to
red, sign
road closed
condition
•Good
for moderate
traffic
with
accident rate
areas
Sensor
canlow
be installed
to detect washed-out
ALERT Signal/Barrier
System
Station will call agencies
Under
towarn
of control
floodingof
ALERT System
Agencies can call station
Barriers
prevent
toget
current
status of
crossing the stream
crossing
when water depth
Closed
circuit
loop
in
reaches
6” over
road
road
can detect
roadprevent
 Sensors
in road
washout
and close
motorists
from barriers
becoming trapped
Installation
is useful
between
where
heavybarriers
traffic causes
ALERT
transmits
water
ahigh
rate of
incidents
levels and times of road
Installation is expensive -
ALERT Flasher/Barrier Spring Valley, CA
Benefits of Warning Systems
 Real-time
water levels for crossing
safety
 Immediate notification of start and end
of road flooding and closure
 Reduced overtime costs waiting for
roads to flood
 Road
 Legal
 No
crews can attend to other priorities
protection for gov’t agencies
excuses for not knowing it was
Considerations
 Requires
dedicated maintenance
 Initial cost can be quite expensive
 Design of system has to match the needs
of the low water crossing
 Procedures need to be established
between agencies
 Legal regulations may need to be
established
Low Water Crossing Systems
For further information, please
contact:
Rand Allan (858) 495-5557
e-mail: [email protected]