National Weather Service United States Department of Commerce

HYDRONET - is the name given to a statewide system of National Weather Service (NWS) maintained, telemetered tipping bucket rain gages. These gages are networked using a series of computers that use software designed and developed by NWS, Pacific Region. The computer systems utilized range from IBM compatible 386 SCO/UNIX operating machines to HP 755 series workstations. The programs are designed to make routine or on demand interrogations of the rain gage data loggers. These data loggers are attached to tipping bucket rain gages and allow the capability of linking with the computer system network to download data, based on rainfall threshold values. These individual threshold values are determined, based on the flash flood threat in the area served by each rain gage. The primary function of this network is to provide support information for forecasting flash floods in the state of Hawaii.

This is a real time rain gage network and has the capability to collect data in 15 minute intervals. Temporal and spatial resolution of these data also gives them the distinction of some of the highest resolution data available in the islands for research. The negative aspect of this data set is the limited amount of quality control available. Many of these gages are in very remote locations on the islands and tipping bucket gage data quality is quite variable, therefore these stations do not meet the NWS standards for certification. This data set, combined with other more reliable, quality controlled data available through various sources in the NWS, can be effectively used for flash flood forecasting and in some research situations. Use this data with caution. Many periods of 15-minute interval data are not available. Data are not available in a greater temporal resolution than displayed on this home page.

Funding for part of the original computer systems used for interrogation and some of the telephone communications lines is from the State of Hawaii, Department of Defense, and Civil Defense special appropriations. Purchase and maintenance of the rain gages and related communications systems are from NWS, Pacific Region general funds and NWS Headquarters special appropriations.