Are wedding allowed in the park?

Yes weddings are allowed in the park but if you wants to use the dam as a background there is 95$ fee and that's for the entire day's use

Yes they are

I have seen them set for a wedding in the grassy area in front of the dam

Yes they are. Got to pay shelter fee.

I think there is a fee but not bad .you need to talk to them soon i think they rent out fast

I don't see why not. I went to a wedding there once. It was in a shelter so they had to rent the shelter for the reception.