To give this context:

Blasting people with water cannons has exactly one purpose - get protestors to disburse. It isn't a tactic to control an unruly crowd into a more orderly one. The water being blasted is at high enough pressures to bruise and it is extremely cold. This is the middle of winter in Dakota - and protestors are also being sprayed during the night.

Many other police tactics and injuries are being reported.