Detecting and Prospecting on the foreshores of a lake or Dam, eg Lake keepit ,Wyangla Dam.

What are the legalities in regards to prospecting and detecting around the foreshores of a Dam or Lake.

In NSW you need permission to fossick/prospect on all Crown Lands.
The permission needs to be sought through the land manager. Where no land manager is in place then permission needs to be sought through Crown Lands NSW.
Generally the overriding land manager of inland dams is Water NSW.

From what I can see Lake Keepit has 3 x Manager's of Crown Land.
Reflections Holiday Park
NSW Sport & Recreation Centre
Water NSW - foreshore areas outside of the Holiday Park & NSW Sports + Rec. Centre grounds.

From what I can see Wyangala Dam has 2 x Manager's of Crown Land.
Reflections Holiday Park
Water NSW - foreshore areas outside of the Holiday Park.

Permission would depend on which areas you are interested in.
The positive is in my experience both the Holiday Park manager's (usually there's a $12 day use fee if not camping or hiring a cabin) & Water NSW are both approachable + generally agreeable to fossicking/prospecting as a recreational activity around NSW inland dams.