Instead of just moving the boulders - place them in a funnel shape, so that the water digs out the river bed for you.
Not sure if this is ideal, but even if a portion of the river bed is scraped off it should leave the nuggets & paydirt.
Might also want to experiment on a small creek with large rocks.
Has anyone done this kind of thing before?
its basically the method I use, I don’t normally dig out a boulder . I work round it and let the water do the work for me, a bit like ground sluicing a whole creek . all I do is pick the middle size stones out the fines wash down stream and the big rocks get exposed so as all you have to do is roll them out of the way. this means if there is gold under the rocks the sudden flush of water wont wash the gold away . each creek is different so there is a different method each time but its still basically the same
Each situation will be different… but good idea.
I often use the cobbles and tailings to raise the water level when I am working in shallow areas to assist the dredge floating… not rocket science but helpful
I always take some plastic bags to dam a small creek. stop leaking. like you say helps float the dredge