Disclaimer

The Urban Drainage and Flood Control District (UDFCD) does not warrant the accuracy of the ALERT data provided by this website. The ALERT database contains some erroneous data. Therefore, the user of this data should not consider any of this data valid without further verification.

All ALERT stations relay data using radio transmissions, which are rebroadcast by one or more repeaters. Radio interference is one common source of bad data. Wind, hail, snow, birds, insects, and lawn irrigation systems affect rain measurements. Human tampering is a problem on occasions. Routine maintenance activities involve manual testing of rain gages, water level sensors, and other devices. Electronic switches on tipping-buckets occasionally malfunction causing false high rain measurements or no measurement. Meteorological data such as wind, temperature, and relative humidity may be affected by physical conditions surrounding the station (e.g. false temperature readings due to rising heat from nearby paved or other reflective surface, false RH values caused by irrigation systems or nearby standing water, false wind readings caused by nearby obstructions). Lightning can also cause false reports. Bogus data is sometimes difficult to recognize, even for experienced users.

Assuming that all ALERT gaging stations are working perfectly, base stations are another possible source of error. Multiple ALERT base stations collect data independently. Consequently, some data inconsistencies between base stations may be expected.

When sensors in the field are electronically adjusted or replaced, the ALERT database record must also be re-calibrated. An uncalibrated record may be difficult to detect. Field maintenance reports, calibration notes, rating tables, alarm settings, and other written records are available for inspection upon request.

Due to the large number of ALERT stations reporting data, it is not practicable to manually correct all erroneous reports received. Attempting to do so would require considerable effort and present yet another possible source for error. Evaluation, interpretation, and verification of ALERT data are the responsibility of the user.

If you experience problems using the ALERT System or have questions concerning this disclaimer, contact Kevin Stewart at UDFCD.