I can see a few problems with this.

First being that you don't know what nutrients the water mostly contains, it might be really high in one thing or another leading to lush plant growth around the pond, however that could also be way too much for a pot plant.

Pathogens, bacteria, parasites are also a concern.

With all the work to make sure you don't kill your plants, or get a shitty yield, it might just be worth it to use nutes