Google ram pumps.
It is a pump that uses the water flow to power itself. No electricity necessary. It can run for months at a time, continuously. They we invented in the 1700s and might work for your application.
We build one this summer to move water from a spring we have, when our tanks went dry.
We have a spring in a steep rocky draw that (amazingly) produced 1/2 - 1 gpm all year long, even through the drought.
We have been tinkering with this spring for a couple years, it is a evolving project.
We cut a "vee" into a 5gal bucket and stuck it under the rock ledge.
Threaded a bung into the bucket and piped it down the draw. There are a series of 55gal drums in the line that act as pressure chambers. Once we got to flatter ground we placed a tote for storage.
We placed a water trough in the bottom of the draw, that is feed by the tote. We also have two other totes there now that we tranfer water from to the other water troughs.
This is how we filled other troughs throughout the place.
We captured the water to 300gal totes, and transferred it to a trailer mounted tote to some water troughs.
Here is a video of the ram pump testing.
The ram pump allowed us to pump uphill approx. 30 rise, and reduce the long trip around and up the steep grade pulling a 2400lb water trailer.
Your application along the river would be ideal for a ram pump. Our pump is fed from a tote and We have to catch the PRECIOUS "waste-water" so the pump sits in a big tub. A river or stream is the ideal use of these pumps.
If it is only or deer/wildlife the quantities required would be FAR less than needed for a herd of cattle.
It kept our cattle alive this year.......wildlife probably benefited too.