alert low water crossing warning systems produced by rand allan, associate meteorologist county of...
Post on 29-Mar-2015
223 Views
Preview:
TRANSCRIPT
ALERT Low Water Crossing ALERT Low Water Crossing Warning SystemsWarning Systems
Produced by
Rand Allan, Associate Meteorologist
County of San Diego Flood Control
The Need for Low Water The Need for Low Water Crossing Warning Crossing Warning SystemsSystems
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 crossings
Stand-Alone SystemStand-Alone System
Warning light activates when water over the road
Good for remote, lightly traveled areas with little accident history
However, there is no notification given to authorities
Warning Flasher - Scottsdale, AZ
•Relatively inexpensive, cost about $1,000 -$2,000
•Can be built in-house
•For about $2,500 more they can be modified for ALERT radio transmission
Automated ALERT Automated ALERT SignalsSignals
Under control of ALERT system
As water first flows over road, lights flash yellow; sign says use caution when crossing
As water reaches 6” over road, lights flash red, sign changes to road closed condition
Sensor can be installed to detect washed-out road
ALERT Flasher - Harmony Grove, CA
•Station can phone agencies to warn of flood events
•Agencies can phone station to get current conditions
•Cost is moderate, about $15,000 to $20,000
•Good for moderate traffic areas with low accident rate
ALERT Signal/Barrier ALERT Signal/Barrier SystemSystem
Under control of ALERT System
Barriers prevent crossing the stream when water depth reaches 6” over road
Sensors in road prevent motorists from becoming trapped between barriers
ALERT transmits water levels and times of road closings
ALERT Flasher/Barrier - Spring Valley, CA
Station will call agencies to warn of flooding
Agencies can call station to get current status of crossing
Closed circuit loop in road can detect road washout and close barriers
Installation is useful where heavy traffic causes a high rate of incidents
Installation is expensive - $100,000 to $150,000
Benefits of Warning Benefits of Warning SystemsSystems
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 crews can attend to other priorities
Legal protection for gov’t agencies No excuses for not knowing it was hazardous
to cross
ConsiderationsConsiderations
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
top related