Ok so, I'm really late on this, since I was playing Bridgeport since it came out, but have you guys noticed that Twinbrook rivers doesn't have water reflection? Or is it me? Because the swampy areas have normal reflection, so does the ponds and such.

They have a reflection for me, but slightly different from the other water areas. This is because the Twinbrook dammed area is actually a whole different thing from the sea water, as discussed in this thread:
http://www.modthesims.info/showthread.php?t=425205

It could be that your graphics card is not rendering this correctly, what settings do you have your reflections at?

Hm, so the dammed area don't have reflections because it's kinda "fake", right? I mean, there is reflection, the general reflection, but not the new reflection that came with LN patch. And anyways, I have the reflection setting at maximum.

Yes, that's right. The mountain lakes in Bridgeport are 'fake' too, so might not have the same reflection (but it would be less noticeable as they are smaller areas).

As a comparison, here are some screenshots of my Twinbrook game, I don't have a great card so you should have a better result.

The dammed lake:



The sea level swamp area:



You can see that the last two do have the 'super' reflection, but the dammed lake does not.

Yea, thats how my game looks too. That's too bad, since Twinbrook have a beautiful landscape and would look really cool with the super reflection, like Bridgeport surely does.