Bridge Construction Problem

[HalcyonSpirit 0]

OK, so here's the problem (with pictures below illustrating it): I'm trying to build an Avenue bridge across a stretch of water, but the game refuses to let me.  It keeps giving me the "grade unsuitable for construction" message no matter what I try.  At first I was like "ok, maybe there's too much stuff near the building site," so I demolished all the buildings and such around it.  No dice (even when I dezoned the area and removed all the underground pipes too).  Then I tried making the land anchors longer; still nothing (actually, the message it gives then is the default message you get if you're still over water when dragging the road/avenue/etc).  I even tried re-terraforming the land to so if it was a slope problem, but that didn't work either.  The area around where I want to build the bridge refuses to let me build it there; it always gives me that same "grade unsuitable for construction" message.  However, if I move down a little bit, the bridge will build perfectly, even across another small island.  But I don't want the bridge THERE, I want it where it won't let me!

Oh, and for the record, I tried building other types of bridges, such as road, street and one-way road, and they ALL work in the same spot, but not the avenue bridge.  Why?  EDIT: Also, I believe I have the Bridge Height Mod installed as well, if that changes anything...

I've run into this problem before, so I'd rather find an answer than try to work around it every time it happens.  I would really appreciate the help.

[Jezus53 18]

Do you have a slope mod installed? I have had problems with bridges ever since I added one. You might want to try removing it (if you have one) and seeing what happens. Also, another trick is to build a road bridge there then demolish it and try the avenue bridge afterward. I know that has fixed it for me before.

[Merlin of Flyote 8]

Make sure there is a completely flat area where you wan't to build the bridge, from your pictures the land isn't flat enough for the bridge to build.