Rain Gauge Data Summary

EAA rain gauge network collects rainfall totals every six minutes from 75 gauges throughout the region

These 6-minute data are made available to National Weather Service in real time. NWS may use the data to aid in tracking storms and issuing flood warnings.

Individual rain gauges are not always reliable indicators of true rainfall over a large area because precipitation can vary significantly, even over short distances. Additionally rain gauges can be susceptible to occasional clogging or other malfunctions and fail to record some rain events.

NEXRAD radar rainfall data from the National Weather Service provides rainfall estimates that are continuous over the entire region. However, the NEXRAD data need to be calibrated based on ground observations from the rain gauges. Thus, the main utility to EAA of the rain gauge network is as a source of “ground truth” for calibrating NEXRAD radar rainfall data.

EAA compiles the rain gauge data into hourly totals for archiving and uses these data to calibrate the NEXRAD radar rainfall data over the Edwards Aquifer region.

The calibrated hourly NEXRAD data provides the most accurate available historical rainfall data for the Edwards Aquifer region. EAA uses this data set for input to numerical watershed models that are used to estimate the amount of rainfall that becomes recharge to the aquifer.

The numerical watershed models can also be used to simulate streamflow responses to storm events.

To summarize: EAA collects real-time rain gauge data at 6-minute intervals and makes this data available to NWS.

EAA does not directly use the 6-minute data, but converts it to hourly data and uses it to calibrate NEXRAD radar data for more uniform and reliable regional coverage.

EAA currently does not make the raw real-time 6-minute data available to the public.

Possibly, applications could be developed to make the data accessible to interested parties through the EAA website or other means.

However, there is concern that raw real-time data has not been reviewed for quality and lack of rainfall accumulation at malfunctioning rain gauges could be misconstrued as indicating zero rainfall.