Well, start with what you know – these artifacts can control water. But not in vast quantities.
So what can you do with a smaller amount of water, then?
You could keep it away from you. Maybe even keep a bubble of air around you, at least if your feet are on the ground. Then you might be able to do something under the water, something that wouldn’t be feasible while swimming.
So, you jump in. The artifacts glow as you approach, and the water gives way around you. Now you need to figure out what to do.
You look up at the big aura, and see that it heads down into the water. It’s like some kind of projection, something smaller having its power magnified. So maybe you can disrupt the source.
You start walking, the water giving way as you go past, and soon enough you see what you’re looking for.
You’re just not sure what it actually is.