"Tim+" wrote in message
...
Doubt it. From the photos of the concrete break up, the earth underneath
had been washed away for weeks beforehand.

I dont see how you can possibly infer that. Its *possible* but given the
speed with which fast moving water can erode riverbanks etc, it seems
equally likely that this was an €œacute€� event.

The BBC article about the dam yesterday or the day before had comments by
various dam experts who were alarmed by the amount of vegetation that had
been growing in the cracks between the concrete slabs in the weeks/months
before. They said that this suggested that water had been getting through
the spillway concrete into the earth fill below. So it's possible that the
problem had been going on for a while. I presume it's a lot worse when the
spillway is actually carrying water than when the only water is rainwater
falling on the slabs.