Tearma Ollannach do na limisteir leata a tugadh chun mintireachais on bhfarraige no o thuilemha abhann agus a chosnaitear o thuilte le cladain is coras caideal is draenacha (mar shampla, an Zuider Zee san Ollainn ). Is minic an leibheal i bpoldair nios lu na leibheal na farraige, agus ni mor uisce a chaidealu amach as cuid mhaith den am. [1]