Maj. Gen. Alan Dohrmann said costs so far total $1,883,736. About $1.08 million is from DES for overtime pay and resources, plus $700,000 in North Dakota Highway Patrol costs.

The Morton County Sheriff’s Department claims expenses of about $100,000 per week related to the protests. It also could apply for reimbursement.

As for the state, “our weekly expenditure is about $263,000. It’s a moving target,” Dohrmann said.

Opponents of the project worry about potential contamination of the Missouri River if the pipeline were to rupture, and about damage to cultural artifacts along the pipeline's route. A portion of the line is set to be bored under the Missouri River less than a mile from the Standing Rock reservation boundary.

The state's estimated costs are calculated based on factors such as the size of the camp -- which has grown to a few thousand, according to law enforcement estimates -- and how long it might remain active. This would determine how great a presence may be required for law enforcement in the area, and for how long.