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Water Resources

Instream Flow Data

Do you have a provisioned water right in a basin with instream flows adopted by rule (also known as Washington Administrative Code 173-500, or WAC)?  If so, you need a reliable way to monitor water availability.

Currently, water users in five watersheds or Water Resources Inventory Areas (WRIAs) can take advantage of this web feature.

The feature provides a reliable way for water users to monitor water availability and voluntarily cut back use when flows are low.  Ecology will add the remaining watersheds as time and staff resources allow.

Instream flow data are provided to inform the public about the amount of water available in the streams and rivers they rely on.  With ready access to this information, people can make better decisions regarding their water use.  If the water measured at the gage is near the minimum flow-level set in Rule, the water user can see this and reduce or cease their withdrawals to meet the flow provisions on their water right.

The following statewide map with highlighted basins is used to link to the instream flow information page for that WRIA.  The information provided on each page includes:

  • Map with USGS gage locations and links to real time data
  • Link to a graphic of the real-time streamflow data for the basin that will also have an interpreted “red line” for the flow set by the WAC
  • List of rights issued with flow provisions
  • Link to the WAC
  • Basin map with color coded stream reaches based upon an interpretation of the WAC
WRIA with Instream Flow Data Page


State Water Use Laws: Compliance and Enforcement

Water is vital to our daily activities.  How we use water affects all of us – our neighbors, businesses, farms, and the environment.  Growth in residential development, business, and agriculture has increased competition for water.  Dwindling salmon stocks and their listing under the Endangered Species Act have heightened concern about excessive water use and compliance with water resources laws.

Laws regulating water use are not new.  Even when Washington’s population was small and water demand was low, there was recognition that water use required regulation to reduce conflicts among competing water users and to protect the resource.  The Legislature established the Surface Water Code in 1917, the Ground Water Code in 1945, and added provisions addressing water for fish and wildlife in 1949.

RCW 90.54, the Water Resources Act of 1971 set the stage for the Chapter 173-500 series of WACs that codify instream flow levels as water rights and a compliance effort to protect those flows