Also when people are comparing to the quick drainage floods commonly seen in MK after a few inches of rain… do not assume forecasts of 15inches of rain means 5x worse.
You are skipping a critical dimension… time.
MK floods because of a high volume of water in a short period of time. Getting delughes of rain that are high rate. The issue is water coming in faster than it can drain (more than the issue being total volume).
The forecasts you are seeing are total rain fall… not per hour rain fall.
Obviously there is a cumulative effect when where the drain goes gets saturated and that’s a major concern in a sustained event like this… but don’t expect 8ft in the MK walkway