River names

Piotr wrote: 

  River names, at least in Europe, are in most cases simple epithets describing the visual appearance ("White", "Shining", "Dark")...

So you think Šventoji means 'shining'? Of course it's the main meaning the PIE root, but both Lithuanian švent- and Slavic *svęt- consistently show the only meaning 'sacred' (which is a semantic derivative of 'shine', undoubtedly). May be you are aware of facts that support the hypothesis that n-infixed (where -n- indicates state, so 'brightened'>'sacred') variant of PIE *kwet- could have retained it's direct meaning?

Sergei