Oleg

11 hours ago, jasong said:

Likely, given it's location. Usually they were built for 2 reasons - either to get water elevation for hydraulic pressure to work benches/terraces in the canyon, or to divert into a dry area outside of the current river channel (dry washes, hillslopes, etc) to hydraulic/ground sluice/etc other gravels - for gold mining. If you follow it up to it's highest elevation you might find the remains of a diversion dam, gate, or channel. And if you follow it all the way to the lowest elevation you will probably find some old placer gold workings, or various points where smaller flumes/ditches branch off to other workings. On ground it can be difficult to know where it ends or just washed away, but you might be able to see the whole flume course on aerials or high resolution LIDAR.

Farmers often made ditches that are basically like flumes for irrigation, to get water up onto elevated fields prior to pumps. But if that one is on the Yuba river then I'd say it's a safe guess it was built by gold miners, farmers wouldn't really build such a complicated structure out of wood either, theirs were mostly ditches. 

I found this place by accident when I launched a drone to take pictures of the surroundings. 
 

Thanks for the suggested versions.
So in the end this design served for gold mining?

Hello,