Explanation of the criteria for classification and numbering of components     F00.3.05
(DEC 99)
Explanation of the dates on the component's description



1.   Purpose and objectives

     To receive, store and display precipitation and streamflow data from ALERT River and Rain Gauges (see components C30.3.01 and C71.3.01).

2.   Description

     The substation consists of a tuned antenna, radio receiver, modem, microcomputer, connecting cabling, an alarm device, a real time clock, and special software. The software running in the microcomputer manages the data input from the remote precipitation and water level gauges,
checks incoming data for validity, and stores them in a database. The operator may display the stored data in various formats, send them to a central computer for further processing, and receive forecasts from the central site, or run forecast procedures directly from the micro-computer. Data may be processed and sent to a home page to share on the World Wide Web. Alert levels may be set so that precipitation rates, or water levels exceeding these, cause an alarm to sound. Alarms may also be set based on rate of precipitation or rate of rise on a river. Other hydrometeorological and environmental elements including temperature and wind run may also be monitored.

3.   Input

     Radio signals transmitted from ALERT precipitation and streamflow stations.

4.   Output

     Precipitation and streamflow data are organized in a database. There are numerous options for display on the console, including precipitation amounts for groups of stations, plot of precipitation amounts and data from a single sensor. These options may vary depending on the software package

5.   Operational requirements and restrictions

     a. Two people should be trained in installation and data base maintenance procedures. About one week of training is required, and can be accomplished concurrently with training on components C30.3.01 and C71.3.01.

     b. Installation requires one or two people.

     c. The software was originally developed for use on mini-computers, and
        has migrated to and evolved on the microcomputer environment. It is
        anticipated that software capabilities will continue to grow along
        with continuing enhancements in computer hardware and software.
        Current software packages run on 16 and 32 bit microcomputers.

     d. Access to a reliable commercial power source or suitable fail safe
        power supply is necessary (11OV or 22OV). It is recommended that the
        base station be located in a facility with 24-hour coverage, to
        ensure a swift response by emergency personnel.

6.   Form of presentation

     Microcomputer, operating system, and peripheral hardware are purchased commercially by the user. ALERT software and documentation is available from private sector vendors. Current software versions are written in computer languages such as C, C++, and Visual Basic. Software and documentation is generally supplied on CD-ROMS.

7.   Operational experience
     Has been used successfully worldwide, with the most extensive use in the U.S.A. Use has been particularly advantageous for basins where time to flood peak is less than 24 hours.

8.   Originator and technical support

     The technology was originally developed in cooperation with the Sacramento (USA) River Forecast Center, U.S. National Weather Service. A list of vendors providing technical support can be obtained from links on the home page of the ALERT Users Group. The address of this home page is currently:

9.   Availability

     From the HOMS National Reference Center for U.S.A.

10.  Conditions on use

     Microcomputer, operating system, licenses for applications software, and peripheral equipment are for sale through commercial vendors.

(First entered: 28 JUL 83

Last updated: JUL 99)