One old school Alaskans remedy:

If it were me I would be cable ing a lot of crushed cars together and stacking them on the bank or that River. Cheap to do and it would work. First order would b to place a few old end dump boxes at a 45 angle fill them with rock at the head of the erosion.  Simple old school and get er done. When the river eats the bank away it will hit all that resistance and take a new path. 

Trees can work but you have to make a triangle and fill with gravel. Can't do that when the river is high. Otherwise logs just float away. The prob is the under soils. Nothing but sand and small pebbles. The kind of soils we have up here. A garden hose can eat the stuff away. 

Looks like a bigger River than ours but the locals down there could get together lots of equipment and local trucks. Prop only take them a week or two