Hmm - that's interesting! In my native homeland Ostfriesland by the north sea, we have an area
with many very old villages, that are built on man made hills made from the marshland's clay.
They built these, because the north sea came for tea every now and then, and those hills where
high enough for halfways normal storm floodings. Dykes came later.
Now, these settlements (which we call Warf) had the names of their main Chiefs, plus "hum" behind that.
One guy's name was Pewe, so his settlement was "Peweshum", which still exists as "Pewsum".
Another was Eilt, so it was Eiltshum, today Eilsum.
Here the historians say, "hum" stands for "Heim" (home). But your version sounds interesting.
Could perhaps the word "home" come from a high and dry place to settle on?