Stream Hydrology Program

Water resources

Stream Flow Reports

The purpose of the Stream Flow Reports is to give a summary of stream flow conditions throughout the state. Flow statistics for a gage in each watershed are calculated from historic flow records. Each watershed is then classified as experiencing high, normal, low or protected flow levels. A fifth category, flooding, is used when flows exceed an established flood level.

There are two types of Stream Flow Maps and Reports used. The Weekly Stream Flow Report is generated on Mondays from April through September. The data for the weekly report are based on an instantaneous flow reading. Therefore, this value can be affected by large storm events, hydropower or dam operations, or other factors that may influence stream flows.

The Annual Stream Flow Report is an average of flow conditions for the specific water year. The water year is from October 1 to September 30 (data available for years 1977, 1985-2002).

An archive of the aforementioned weekly and annual stream flow reports was assembled into a single file and is available for download PDF icon. (19.4 Mb).

To ensure timely production of weekly stream flow maps, preliminary data are used. Only the annual stream flow maps are updated with final data.