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Arizona Flood Warning System
Background
In January 1993, heavy precipitation caused extensive flooding in many areas of
Arizona and resulted in hundreds of millions of dollars in damage. During the floods, local
response efforts were hindered by poor coordination among agencies and by a lack
of information on flood threat. A number of local and state agencies routinely monitor
flood threat using individual networks of automated precipitation and stage gages,
weather stations, radar data, and satellite imagery, but the means to share this
information was limited. In response to the lack of inter-agency communication links,
these agencies formed a Multi-Agency Task Force and have met regularly since 1994
to improve flood threat assessment and communications.
As a result of the extensive flooding, the U.S. Army Corps of Engineers (Corps)
began a reconnaissance study to evaluate the need for statewide flood warning services in
Arizona. The study was completed in 1994 and included a recommendation to develop a statewide
flood warning network. In addition, the Flood Control District of Maricopa County,
Arizona, commissioned a study to develop a conceptual design of a statewide system.
System Design and Construction
The Corps entered into an agreement with the Arizona Department of Water Resources
(ADWR), and in 1997 they sponsored the design and construction of the Arizona
Flood Warning System (AFWS). The project
goals were to 1) improve data collection of existing real-time precipitation and
stage gage networks in
Arizona; 2) strengthen or establish communication links among agencies for better
data dissemination and coordination; and 3) expand coverage through installation
of additional gages and repeaters.
Design and construction of the system was completed in 2001 and included the installation
of 58 additional precipitation and stage gages, and 5 new repeaters.
The system also included a communications network and base stations at 11 Arizona
counties. Since completion of the initial project, ADWR and other local member agencies
have continued to enhance the system through installation of additional gages and
repeaters, field maintenance, routine computer hardware and software upgrades, and
regular coordination during Multi-Agency Task Force meetings.
Current Operations
The AFWS collects rainfall and stage information from data collection sites statewide,
and transmits the data to participating agencies using Automated Local Evaluation
in Real-Time (ALERT) technology and line-of-site radio telemetry. Data are transferred
to and from a computer hub located at the Salt River Project.
In addition, there are a host of products offered to aid in assessing flood threat.
Weather data are currently available from the AFWS website, including radar and
satellite imagery, watershed conditions, Salt River Project reservoir operations,
and U.S. Geological Survey (USGS) streamgage data from around the state.
Plans for the near future include adding information on drought monitoring.
Throughout the planning, design, and construction of the AFWS, the Multi-Agency
Task Force has assisted in coordination tasks, site selection for new gages, technical
review of the gage and computer network design, and securing permits. In 1999, the
AFWS received the Pioneer Award from the National Hydrologic Warning Council in
recognition of its efforts toward improving flood warning services and inter-agency
communications.
Written by Laurie T. Miller, LTM Engineering, Inc.
MATF member since 1994
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