That could be near American Falls, ID. Massacre Rocks state park along the Snake River looks like that.
You might find it here:
Looks more like Hagerman Valley west of Twin Falls. The ground is sandy there and they used the rows of Lombardy Poplar trees to hold the banks. I recognize the bluff as looking toward the north from the Billingsley Creek area. spent a lot of time there as my Grandparents lived near that spot.
I was thinking King Hill or Glens Ferry
A little research could help place the picture better. It could well be from any of the three areas. The Twin Falls Library has a great photo collection and would be a good place to research this out. Wish I was a bit closer.