This bridge might ought to also be added to the 'inundated' category, as I have heard in the past that it still exists under the water of Lake Dardanelle.
The location of the bridge was closer to the railroad, I believe, as Highway 64 used to continue along what is now Marina Rd. and continued straight along the west side of the railroad (Marina Rd. now curves away from that original alignment, which can still be partially seen). The old alignment and bridge was bypassed by the current alignment due to the construction of the Arkansas River dam and creation of Lake Dardanelle, so the site of the bridge likely is undisturbed.
Obviously some confirmation would be helpful.
Original plans can be found here: