The high-power pumps can empty the reservoir in four months and consume large amounts of energy. A hundred pipes could empty it quicker and cost little.
I was listening to the news earlier and they are trying to build a dam to prevent further water getting into the reservoir as they are already pumping/syphoning the water out.
Perhaps the answers asking where would the water go or saying they'd need a large hole were joking: pipes draped over the good part of the spillway would of course have siphoned water onto - the spillway!
It occurred to me that a spillway is unlikely to be expected to drain a whole reservoir, just the excess. Still has to go somewhere without making a village into marshland. But good luck to them if they find a way. Having stated that, the clay/soil foundation seems fine. Unsure much draining is useful.
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