A Milky White substance and Foam observed when the Oroville spillway reopened April 14. I did some research & found this. Overflight video, in the morning of April 15 by locals, reveal the origin is within the spill turbulence from the canyon outflow.
Deflection of this flow, on the opposite side of the river bank, reveals the milky white substance & foaming to branch both directions (upstream and downstream based on the riverbank backstop).
A second overflight, closer to mid-day, reveals the material subsiding. This indicates it was an initial condition from the spillway turn-on and lessened when "washing" purged the source.
The Central Valley Regional Water Quality Control Board was notified and they took samples to determine the source of the foam. (see article link). The results won't be known for 2 weeks.
Not sure why, but, the agency supervising engineer, Bryan Smith, commented that "It might be 'foaming agents' in the water, or natural causes might be found. Smith said decaying plants and algae can cause foam in water, or a change in water temperature. Pollen can also appear like foam, he said".
I suppose that they are not aware of the video of the overflights. If so, I believe it would immediately lead them to investigate if all of the myriad of coring/drilling & drill mudding in the Upper Main Spillway may be the cause. Keep in mind that there is likely a fractured rock sub base in the Upper Spillway. Core Drilling could have injected an amount of material used in the coring process. Then there is the re-sealing of the core holes to ready the spillway for re-opening. The underdrain system beneath the slabs would easily wash and port the fluidic leftover material into the sidewall drain chutes.
Hope they used an "eco-friendly" material. We'll see what the test results come out to be. btw- DWR may have had a hint of this early on by observing the water drains… unless the "foaming" required turbulence & mixing of minerals in the canyon..
= = Mercury News Article snip
Oroville – Foam floated downstream and made circles on the water last week in the pool below Oroville Dam. Water quality experts are trying to determine why.
Oroville Dam: Mystery foam appears below damaged spillway
Mystery Milky White substance & foam flowing in the diversion pool caught the attention of locals. Central Valley Regional Water Quality Control Board was notified & samples taken.
Milky White substance + Foam observed originating at spillway turbulence from canyon - outflow from Upper Main Spillway. Material goes upstream and downstream from bank flow back pressure hydraulics.
