Yes, females will lay unfertilized eggs. However, if I remember correctly, these turtles joined your pond as adults and not too terribly long ago? Female turtles can store sperm for as long as 5 years . . . . so those could be viable eggs.
You can leave them there and protect the nest or you can dig them up and move them if you want. Incubation can be tricky - temperature can determine sex - but can be done if you are careful. Or you can dig the eggs and put them in some kind of container and keep it in a safe place outdoors. Just be sure that the eggs stay the way they were laid - do not rotate or turn or you'll destroy the embryo and that they don't end up in sitting water as they will drown.
If they are going to hatch, it will happen in 60 to 90 days. Mine always seemed to take exactly 70 days from laying to hatching, but it can be more or less. The number of eggs increases every year the female lays - so you could have anywhere from 3 to 12 or more eggs in that nest.
And you can ship a couple of those babies out this way if you want . . . . .
