I think you could ignore 'substrate movement' for all but the more rapid torrnts of water (that probably, in reality, wouldn't 'take' impact ripples too obviously over their already turbulent surface[1]) and you could always apply a time-related skew upon the not-concentric circles[2] if you have a flow.
Interfering ripples mostly would look like they pass through each other (yes, high+low should look like flat, and double-high/low ought to be more prominent, but unless you're spamming ripples you can probably assume the highlights cross each other in a suitably pleasing way without arranging any special redrawing). And with banks being at tile-edges, if you have graphics for a 3x3 'splash' in 9 tiles and you have the left three tiles actually as ground you can not-draw the left three ripples on the bank and instead overdraw the right three ripples (assuming symmetry, otherwise flip the left three as you translate them) over onto the middle column to give a suitable bank-reflective effect. You could simarly fudge the effects of round-the-corner propogations (and ignore it if its a built floor with water beneath, not solid bank).
The issue here still isn't much an artist issue, but whether the calculations (that already include whether to apply grass-edging/etc to paint over adjacent tiles where slope or stream exists) want to be done to allow such fairly simple art to work.
(And maybe, after such a mock-up, it might need a tweak. Though I'm under no impression it would exactly match Real World fluid-dynamics, just that it could sufficiently look like that to satisfy (most) people, aesthetically. Then you just need to add 'wakes' (standing V-shaped waves) to bridge-footings/similar in sufficiently rapid waterflows (skewed by flow-rate) and it'd be amazing. But probably a Stretch level aim.)
[1] Fast enough and there'd be a wake, essentially the equivalent of a supersonic/near-supersonic wavefront.
[2] I was thinking of an animation that's something like: splash-dot; small circle; largish circle and splash-dot; largest circle (fading) and small circle; largish circle; largest circle (fading)... This being six frames. But if you had four frames of just a single dot/circle and overlayed then they could be frame-dragged by any current, you could activate on entry/exit of any item (or if used for fishing as well, a potential bite) and would be less overall raw graphics (for more layering).