The bronze coloration in the fall is a trait of the plant and is sought after.

A high water table is bad, very bad. It is best to plant in a raised bed in such a situation. But the problem you see doesn't seem to be acidity related or root rot.

Low soil acidity causes chlorosis, yellowing of the leaves between green veins.

Root rot causes general decline of the entire plant, not just a couple branches.

The dieback you see can be caused by borers, or by a summer drought or even some roots in too wet an area. It is best to remove the dying branches and destroy them.

If the ground is too moist, replant in a raised bed.

Here is a link that might be useful: How to care for rhododendrons and azaleas.

It may be any of the things rhodyman suggests, but it may be the result of plain old winter cold. Z5 is very difficult for most evergreen azaleas even when the label says "Zone 5 Hardy".Winter is especially damaging if the azalea is not protected from wind and sun.

Your azalea is obviously alive, so if you wait a while and then prune back to green wood it will regrow this summer. Next winter give it some protection - evergreen boughs are good, deep snow even better.