Due to a low May water supply forecast that is 5.129 million-acre feet (April – August), 84 percent of average, the U.S. Fish and Wildlife Service’s biological opinion for Kootenai River sturgeon allows a volume of 0.8 MAF to be used for augmenting spring sturgeon flows. Volume forecasts of 4.8 to 6 MAF puts this year’s operations into a Tier 2 category. A water supply forecast of less than 4.8 MAF would be Tier 1 and would allow no augmentation for sturgeon.