On sea or land?

I installed Greek Airport Project's sea bases scenery, which is nice - but there's a problem. They don't have a forum of their own as far as I can see, so maybe someone here can help?At one of the bases, aircraft bob up and down as if they are in the ocean, when they are in fact on dry, brown earth, several dozen metres away from the sea.How to I shut off this effect in the scenery, so that a/c don't sink into what is solid ground and start 'riding the waves', as if they were on water?Thanks,Martin