Local authorities and the other agencies need access to large amounts of money at short notice in order to respond to floods. Government has promised about £14 m so far - a fraction of esitimates, and the equivalent of about 4 hours' spending on Trident (I use the Trident Hour, conservatively given as £2.6 million, as a useful unit of Government expenditure).
A better way to fund floods and disasters would be to have a pooled insurance fund into which all relevant agencies including HMG pay, and on which they can call at short notice when disasters happen. The fund would be ethically invested.
We also need to push for far greater investment in flood prevention. But everyone is doing that anyway.