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 u Flooding claims scores of lives each year u Each foot of water rise displaces up to 1500 lbs of vehicle weight u Lateral force of a flooding stream can place over 500 lbs of force on a vehicle u Small vehicles and pedestrians can be swept off the road in as little as 6”-12” of water u Flood waters can hide washed-out
Low Water Crossing Warning Devices Three Examples
Stand-Alone System u Warning Flasher Scottsdale, AZ light • Relatively activates when inexpensive, cost water over -$2, 000 about $1, 000 the road u Good for remote, • Can be traveled lightly built in-house areas with little • For about $2, 500 accident can be more they history modified for ALERT u However, there is radio transmission no notification given to authorities
Automated ALERT Signals u • Station can phone agencies Under control of ALERT Flasher Harmony Grove, CA to warn of flood events system u As water first flows over road, lights flash • Agencies can phone station yellow; sign conditions to get currentsays use caution when crossing • Cost is moderate, about u As water reaches 6” $15, 000 to $20, 000 flash over road, lights red, sign moderate • Good forchanges to traffic road closed condition areas with low accident rate u Sensor can be installed to detect washed-out
ALERT Signal/Barrier System u. Station will call agencies u Under flooding to warn of control of ALERT System u. Agencies can call station u Barriers prevent to get current status of crossing the stream crossing when water depth u. Closed circuit loop in reaches 6” over road can detect road u Sensors in road prevent washout and close barriers motorists from becoming is useful u. Installation trapped between traffic causes a where heavybarriers u ALERT incidents high rate of transmits water levels and times of road u. Installation is expensive - ALERT Flasher/Barrier Spring Valley, CA
Benefits of Warning Systems u Real-time water levels for crossing safety u Immediate notification of start and end of road flooding and closure u Reduced overtime costs waiting for roads to flood u Road u Legal u No crews can attend to other priorities protection for gov’t agencies excuses for not knowing it was
Considerations u Requires dedicated maintenance u Initial cost can be quite expensive u Design of system has to match the needs of the low water crossing u Procedures need to be established between agencies u Legal regulations may need to be established
Low Water Crossing Systems For further information, please contact: Rand Allan (858) 495 -5557 e-mail: rallanpw@co. san-diego. ca. us
Скачать презентацию ALERT Low Water Crossing Warning Systems Produced by
be1be1bfd510c6374494fe3235f5f7f5.ppt