How safe is my Island ?

[Prep Girl]

In one way living on an Island would be ideal, if the whole Island pulled together , you can see all around for defence, like you said plenty of water and fish, grow your own stuff, take Guernsey 36 miles around? lovely Little Island, but how high above sea level are you? if there was sever flooding due to weather/tsunamis would it contaminate your water source? Take away the fish and fresh water and add no fast escape? and if there was a Zombie invasion you'd be funked lol