ALERT 2™
ALERT2 Protocol Improves Data Collection Capabilities for Automated Flood Warning Systems (AFWS) and Environmental Monitoring
ALERT2™ is the new standard protocol designed to replace ALERT (Automated Local Evaluation in Real Time). ALERT2 provides a graceful transition of real-time data collection systems from providing slow, lean, error-prone environmental data to receiving fast, information-rich, error-free knowledge about events in the real world.
There are many benefits to the ALERT2:
- Faster by more than 10 times; much greater system capacity
- Full error detection and forward error correction; good data or no data
- Use of time division multiple access (TDMA); GPS-accurate clocks and no more traffic jams
- Large identifier fields; many more site and sensor identifiers
- Unlimited message content; full engineering values, rich information
- Protocol can be extended to support custom messaging needs
Initiated in the mid-2000s, the open standard is trademarked by the National Hydrologic Warning Council and developed by the ALERT2™ Technical Working Group, a subset of the Standards & Guidance Committee. The primary ALERT hardware and software vendors are all committee participants, as are U.S. and Australian agency members. This new standard is being adopted by multiple vendors to offer customers competitive choices.
The latest version of the ALERT2 Standard documents are currently posted at www.hydrologicwarning.org.
ALERT2™ is designed to provide a graceful, cost-controlled transition path for existing ALERT systems. First, the repeaters in the system are upgraded to ALERT2™ Concentrators, which receive both ALERT and ALERT2™ reports and transmit ALERT2™ messages to the base station. This hybrid system model allows agencies to replace hardware at gauging sites when it’s convenient and they have money to do it, yet improve their overall performance immediately and perhaps dramatically by increasing the capacity and eliminating transmission errors on the “last hop.”
OneRain Leads the Way in Implementations of ALERT2
OneRain has led the first two implementations of the standard, one for the Urban Drainage and Flood Control District (UDFCD), Denver, CO, and the other for the Overland Park, KS, Flood Warning Decision Support Project and Stormwater & Traffic Operations Center Integration Project, a regional system that includes the Kansas City, MO, gauging network (OP/KCMO).
The UDFCD is operating its existing ALERT repeaters in parallel with ALERT2™ Concentrators, enabling ongoing comparative analysis of the old and new protocol. OP/KCMO has replaced their ALERT repeaters with ALERT2™ Concentrators. Both systems have been in place for more than a year. Both systems are preparing for the next step; sending ALERT2™ data from the gauges.
The performance of these first two implementations has been excellent. The comparative performance statistics in the UDFCD system are striking: Only about 1 in 10,000 ALERT2™ reports were lost, compared to 2-4% of ALERT transmissions during modest rainfall events. Data losses as high as 70% have been observed in large ALERT networks during storms, so the contention-free ALERT2™ channel will make enormous contributions to improved data collection.
Keep an eye on our site for the latest developments in real world ALERT2™ projects!
ALERT2™ is a trademark of the National Hydrologic Warning Council (NHWC)
