I've tried a few tactics on this map - but eventually gave up trying to use the bridge on the left - even with plenty of smoke for cover I still lose too many soldiers trying to cross it (smoke only seems to be effective at longer ranges - it's great for crossing the bridges in Rom(e) tho ).
So - euipment wise I tend to stick to longer range weapons - laser rifles for preference as they are the best all round weapon in the game - but assorted machine guns, assault rifles and sniper rifles if its earlier in the game.
2 -3 guys take out the 1 or 2 aliens that are normally in the building on the left - oncew that building is cleared I leave them near the hole in the wall under cover during the aliens turn - taking turns to step out during their turn and snipe at any targets of opportunity on the opposite side during my turn - that also prevents the aliens from making any attempt at crossing to my side - although I'd love to mine the bridge with proximity grenades and watch them try
(we're getting those soon right?)
The rest of the squad move slowly towards the building on the right near the other bridge making sure they stay in cover during aliens turn - if that isn't quite possible I improve my odds with a few smoke grenades.
After taking out the alien that's often in the right building I gradually assemble my squad on the right hand side with reaction fire set - and take the time to sort out any medical attention and reloads - this normally gives me the opportunity to take out a few on the aliens in the buildings on the right hand side of the opposite side of the river.
Then, taking advantage of the natural cover (rocks) on both sides of the bridge - and a little more smoke, I make my move across the river.
At this point I then move the 2-3 guys I have left behind in the left side building onto the roof with reaction fire set - that way they can keep the aliens in the buildings on the left pinned down while the other half of the squad clear the buildings on the right - to do that I normally split the squad with half going behind the buildings and the other half coming in from the front - pincering the remaining aliens in there.
After that it's a simple mop up if my snipers on the roof havent already done that for me