REPORT: Swan Falls AADF Update | July 20, 2026

Swan Falls Adjusted Average Daily Flow (AADF) Update

Based on provisional data, the July 19 three-day average AADF was 4,292 cfs, which is 392 cfs above the minimum flow requirement.

These values are preliminary and subject to revision. Conditions will continue to be monitored, and updates will be provided every Monday unless more frequent updates are needed.

“Adjusted average daily flow” is the average daily flow at the Murphy Gaging Station that has been adjusted to account for Idaho Power operations. For more information on the Swan Falls Settlement, calculations, and reports, please visit the Swan Falls Settlement page on IDWR’s website.

The graph includes four data series:

• Black line: 2026 3-day averaged, adjusted average daily flow (AADF). This is the primary value used for water management and administration under the Swan Falls Settlement.
• Blue line: Observed 2026 streamflow at the Murphy gaging station.
• Red line: Historical minimum daily flow for the record period of 1981–2024.
• Green line: Historical median daily flows for the record period of 1981–2024.
• Salmon shaded area: Minimum streamflow requirement established under the Swan Falls Settlement. The requirement is 5,600 cfs from November 1 through March 31 and 3,900 cfs beginning April 1 and ending October 31.

Please use the three buttons below to access this week’s AADF calculation products. Additionally, we encourage folks to review the Swan Falls Settlement Overview for historical context and responses to frequently asked questions.

If you’re unsure whether you have a Trust Water Right, explore IDWR’s dashboard by clicking the button below.

About Idaho Department of Water Resources

The Idaho Department of Water Resources strives to serve Idahoans by ensuring their water is conserved and available to sustain Idaho's economy, ecosystems, and resulting quality of life. Visit its website at https://idwr.idaho.gov/

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