I gather you mean 'House Flood Plan' rather than plain. This can mean a few things but both relate to the safety of the occupants in a house in the event of a flood occurring. In some jurisdictions a flood plan is needed to be given to the building authority to show the new home has flood mitigation drains or swales, is built high enough not to be flooded, or has a flood evacuation plan. It can also mean a council authority plan that shows where flooding has occurred in a district and where you could safely build a home.
The flood plain
As far as I understand it, peril and hazard are two different things when used in the insurance context. Consider a house built on a flood plain. In the event of a flood the house is damaged. The peril in this case is flooding while the hazard is the location of the house on the flood plain.
The flood plain. Delta
There are two examples of flood Plain which are as follows:Active Flood Plain.Old Flood Plain.
I live in a flood plain, along with many others.
there is 896 square kms of flood plain
flood plain
York is situated on a flood plain
Move out of the flood plain.
a canyon, gorge or vale
It is a flood plain.
Simply put: Because Centralia is built on a flood plain. A better question would be: Why did people build on a flood plain?