FEMA has an interesting calculator on its website. It does not embed into the WordPress Blog, but the link below should load it for you. It allows you to develop an estimate as to the costs you would incur should your house flood. These costs are based upon National Averages, and costs here on Cape Cod would probably be somewhat larger.
If you look at the flood map for your property on the Dennis website
and turn on the layer for Two Foot Contours, you can learn approximately what your water level will be on your property. Apply that depth of water (flood height minus ground elevation under the house) to the Cost of Flooding Calculator and it will give you the average costs.
For the example above, the flood elevation is and AE 12 and the land under the house is elevation 8. A basic analysis would say it could be subject to 4 feet of water. The Cost Calculator says the property, with a 1000 sf footprint would suffer $74,580 in damages.
Test it out for your property.