Police say David Persons, 31, of Boise was drunk at the time of the crash.
The Boise County Sheriff's Office says Pearl Sittner, 4, of Boise, was in the SUV with four other family members last August when it went off the road and slid 90 feet down an embankment before stopping.
The girl's parents were able to get two other children out of the SUV, but were unable to reach Pearl before the SUV broke loose and slid another 60 feet down the embankment into the water.
In Boise County court on Thursday, a judge said Persons will have to serve two years in prison before he's eligible for parole. However, the judge retained jurisdiction, which means he will enter a program that could eventually have him serve his sentence on probation.
His driver's license will also be suspended for 10 years following the end of his sentence.