Sumas Washington was once a lake. But the November 15 atmospheric river dropped a massive amount of water ..it was a RECORD amount of water across the border in British Columbia Canada. Have you though about and can code allow it, to replace the foundation with a floating Styrofoam block that would allow your house to float during floods? I dont see why it would not work after all homes float one water in floating home communities all the time. Here is the record flood in abbotsford. The Loss of many bridges across highway one was a all time record for Flooding damage.