Not a probem really, if you ask me. The scene is not going to be inferior just because the water is not wild, and no birds. I would just keep going with the scene, continue to make it beautiful, find a few interesting spots the camera can look at and so on. Maybe you have some clouds rolling in, some strands of fog moving here and there....
Of course you can choose to work on a different scene, there's no problem at all with the contest rules. What counts is your final submssion, nothing else.
best regards,
Frank