Officials say that's needed to meet the water demands in the yellowtail reservoir for the rest of the year. But wildlife experts say that step could cause significant damage to the river's trout population. "The national park services that manages the recreational services for big horn area, and likes to see a big pool for recreation, that those big interests are trumping the world class fishery that is below the dam." says Bob Gibson of Montana Fish, Wildlife and Parks.

Meanwhile, Dan Jewell of the Bureau of Reclamation says "We have to do a balancing act and do our best to provide in a fair way to the various users out there." Jewell says that the recent cold and dry weather has played a big role in the need for filling the reservoir.