'science folk claim that there is absolutely no evidence for such a flood.'
That's fine. Bible believers say that there is absolutely no need to believe in such an event as history. The story is more prophecy than history. The allegory of Noah illustrates a spiritual theme, that of salvation from spiritual death through Christ, who is represented by the Ark, the flood waters representing spiritual death. There is abundant detail in the story to support this view, and much of it cannot be represented in translation, and may need explanation even when translated adequately.
There are some who find the spiritual meaning too challenging, so they become 'liars for Christ'. To be consistent, they must posit a date for the literal flood of 2350 BC, and are also forced to say that massive volanic eruptions took place simultaneously. This event, that would have destroyed all life on earth bar a few anaerobic bacteria, was of course followed by several ice ages, all in time for Stonehenge to be built c. 2200 BC!!!!!
In America, Christ sends 'em doo-lally.