August runoff was 1.5 million acre-feet, 109% of average above Sioux City with most of the runoff entering the System below Garrison Dam. September runoff in the upper Basin is forecast to be well below average, especially in the Fort Peck and Garrison reaches. The updated 2025 calendar year forecast for the upper Basin is 19.1 MAF, 74% of average. Average annual runoff for the upper Basin is 25.7 MAF.