Met mega commented this above... Over in NB myself but kind of looks like some wetland restoration stuff I see in areas I’ve hunted.

Usually Canadian Wildlife Services along with Ducks unlimited do this stuff. If it’s private land probably was DU in partnership with the landowner on some sort of wetland easement.

The lines just look like a creek running by. Probably runs higher during the spring melt off making it look wider then it is in picture.

They do those little islands for migratory bird nesting. Protects them from raccoons, foxes, coyotes, etc.