dickfoster
Elite Member
Spoils: I don't know the specifics for this but in general: in the 1800's, Hydraulic Mining was used all along the Sierras. This used giant 'monitors', jumbo fire nozzles, to make erosion and wash gold down into sluice boxes. Erosion like we've seen in these recent photos was the objective.
This dumped so much spoils, light material, into the rivers that 70 miles downstream from Oroville there are still abandoned 1800's sailing vessels buried under sediment at the Sacramento waterfront. Back then floods buried farmland under infertile mud, and the beds of the rivers loaded up with sediment and became higher, increasing the severity of flooding. The environmentalists of the 1870's got hydraulic mining outlawed because it was imposing huge costs on everyone downstream.
This present event had its strongest effect in the fish hatchery downstream that got overwhelmed with mud so the fish were trucked elsewhere. Farther downstream - I don't know. That stuff won't get flushed down to the ocean very rapidly so there has to be some effect.
You should see what that mining did up here. Much of it still looks like a moonscape to this day. Plus they dumped a bunch of mercury into the sluice boxes to mix with the fine gold dust to recover it. That stuff is still laying in the bottoms of streams up here too. It's hard to imagine the massive amounts of earth that was washed away downstream until you see it with your own eyes. Millions upon millions of cubic yards of earth were simply gouged out of the hills around here.