Water flow under the main spillway?
At least 5 inches of rain due Sunday - Tuesday in the mountains above Oroville.
Inflows have the potential to exceed 200,000cfs.
https://www.wunderground.com/cgi-bin/findweather/getForecast?query=Paradise%2C+CA
>>>Water flow under the main spillway?<<<
This crest is most likely from the high volume flow over the main spillway surface (i.e. very unlikely from anything under the slabs). The symmetrical shape of the crest infers a collision of flow from the inlet - analogous to “streams” colliding.
Still, you always seek to maintain a laminar smooth flow. The image is not completely definitive but it looks as if the crest is away from the side wall.
The concrete of the main spillway has a large number of microcracks that are repaired by maintenance - in addition to the concrete slab joints. However, one section of the seam of the main spillway experienced a “slumping” (believed to be from undercutting erosion under the slabs). This is what led to the blowout in the midsection of the main spillway (i.e. the fix to this “slumping” was not adequate over time).