In my very un-educated opinion, this is what I think about how long it will take for Peacock and Little River to "clear" back to what we're used to:
During a "normal" flood, the walls of Peacock get somewhat stained by the tannic water, and this quickly wears off as the clean water pumps back out of the system. "Normal" floods occur in the spring, when the water temperature of the river is several degrees below the spring water temperature. I was part of what I think was the last dive team in Peacock before it closed for the spring flood last year. The river water and tannic intrusion was around 68 degrees, while the clear spring water in the cave was 72.
This most recent flood was not a "normal" flood. Most of the staining on the walls is not tannin, it is algae growth. The river water flowing into the cave was 76-78 degrees and laden with algae. As a result, the algae was able to take hold on the walls and thrive in the warm water. When I was at Peacock a few weeks ago, the water coming out of the cave was still in the 74-75 degree range, rather than the normal 72.
I think the algae is still around because of the warmer water temperature, and it will gradually die off and fall to the floor as silt as the water temperature returns to normal. I'd guess it would happen slowly and may take several years, especially if we don't have much of a cold water spring flood. But if we do have a decent flood, I think we'll see a significant change during that flood in the spring.
Just my thoughts, let me know what you think.
