The significance here varies according to the details and action of the dream. If the creek was dry, it portends a disappointment, probably to do with business; if it had a normal amount of water running, it augurs some pleasing new experiences. If you were swimming in it, you can expect some exceptional luck to come your way; but if you only observed others in it, it could be a warning to pay more attention to your own interests, or others may benefit from your efforts.