I don’t fish impoundments but I do fish fresh water for barra mainly lagoons and billabongs.
Will try and help as best as possible.
Patterns I have sort of identified.
Night fishing is best/full or big moons better.
Gold is a real good colour for freshwater barra also get yourself a tiger lily bomber.
You need to use a sounder in deep water to identify what level to troll at.
Trolling covers more water but make sure you jig the lure don’t just prop it in a rod holder.
In cooler times try small lures real close to the cover i.e lily’s or snags
Live bait is also a productive option for bigger fish.
I prefer to use shallow divers at first then work deeper lures as you try and find the fish.
I could go on and on but I don’t know how lagoon tactics translate to impoundment ones.
P.S impoundment barra are not breeders so if you nail a meter fish don’t feel bad about keeping it for a mount as it would probably taste like a carp!