River and stream flow monitoring

We maintain a network of stream-gaging stations that report streamflow conditions in rivers and streams across the state. The information is used to monitor flow conditions for water supplies for people and migrating fish, recreational activities and to develop strategies to respond to climate change. The data we collect are available to view and download.


Continuous data for rivers and streams

The Freshwater DataStream application contains nearly real-time data for our long-term monitoring program. Data show streamflows and some water quality parameters gathered by our automated stations. It also contains historical data records for discontinued stations.

Impacts of climate change on streamflow

We have been monitoring streams for decades, and our long-term streamflow data show that lower-than-normal summer streamflow levels have become more common in recent years. Streamflow seems to be decreasing over time all across the state. This trend appears to align with warming weather trends.

The low flows interactive dashboard below can help you to see these trends in five different watersheds in the Puget Sound Basin. For each river and stream site, compare:

  • The percentage of days that the site had unusually low flow for each summer over time.
  • Daily flows in a given year against historical conditions at the site.

The Freshwater DataStream application contains nearly real-time data for our long-term monitoring program. Data show streamflows and some water quality parameters gathered by our automated stations. Freshwater DataStream shows continuous data from active monitoring stations. It also contains historical data records for discontinued stations.

Check out our Statewide Stream Summary Map to see nearly real-time summaries of streamflow conditions around the state. Color-coded dots indicate if today's flows are above or below normal for this time of year.

Learn about streamflow monitoring methods

Flow monitoring methods for rivers & streams describes how we measure how much water flows through rivers and streams.