In message , at
17:01:15 on Tue, 6 Aug 2019, Robin remarked:

Some rather more than averagely informed comments are at
https://www.sciencemediacentre.org/e...s-that-the-wha
ley-bridge-dam-has-been-damaged/

"Within the last few years new valves have been placed in the dam to
expedite rapid drawdown in emergencies: presumably, this is happening
now."
Although the question being asked in this thread is "if that's the
case, why also use lots of pumps".

well I don't claim to have any engineering qualifications but it seems
to me a plausible answer is in the public statements:

- the spillway was damaged leading to a risk of catastrophic
failure,

- there was a lot of water in the reservoir

- water was still coming in at a high rate (and with the risk of
more rain to come)

so it seemed like a good idea to lower the level faster than would be
possible without the pumps (with the added benefit of being able to
send water to different places and so avoid downstream flooding).

To the best of my recollection and belief, all the above is on the
public record.

But it's also speculation that those bullet points above are either
accurate or exhaustive. We are still in a "fog of war" phase.
But then some prefer speculation.

So it's down to what the informed commentator above means by "rapid",
perhaps.
--
Roland Perry