Well, I'm sure there are certain Butcher'esque takes on the subject of water, but taking from what I've absorbed from various other myths and fiction, contact with water is more likely to diffuse magical energy than mere proximity. Think of it like electricity. The charge hits the water and goes everywhere at once. Without that direct contact, it's probably less of a problem.
On the subject of bridges, I'd imagine they could be dealt with pretty easily. Bridges are significant objects. People put a lot of practical and metaphorical importance on them. They bridge gaps, make crossing normally impossible divides possible, serve as meeting places, places of suicide (sadly), and carry with them a lot of spiritual significance as a result. Especially particularly large, famous bridges like the Golden Gate that often stand for something greater than their mere utility. That kind of spiritual significance likely makes them magically present locations, and thus they probably allow the transit of magic and its practitioners without much trouble at all (maybe one of the reasons trolls favor them, a comfortable magic friendly area to hide out and snatch "lunch").
So from that standpoint, I'd say magic on or across bridges is fair game.
Now magic in and close (like shoreline close) to running water is perhaps more problematic. In water for obvious reasons, being close maybe being effected by the amount of water in the air (though that's more scientific than anything) and the spiritual significance of shores where crossings become something one has to consider the likelihood of accomplishing (most people aren't going to attempt swimming a big river). The physical importance of such a boundary, and the divide it represents likely have a spiritual weight of their own, making magic across it harder to focus. I would think that especially in horrible weather with high tides, all of that active energy and water would conceivably make it much worse, even with storms usually being a source of power. It would be, to me, kind of like squirting a water-gun into a hurricane. It wouldn't accomplish much.