The Connemara village of Leenane, which has been physically divided by this week's weather, may have a pedestrian bridge by this evening, according to Galway County Council.
However, a temporary bridge suitable for vehicular traffic through Leenane will take several weeks to construct, its senior engineer, Martin Lavelle, has said.
The century-old stone-arch structure over the Lahill river at the mouth of Killary fjord collapsed shortly before 5pm on Wednesday due to a combination of heavy rainfall and a landslide upstream.
No one was on the bridge at the time, but the incident was videoed by a visiting group of Danes.
"We've seen the film footage, and it all went down in the space of just two minutes," Mr Lavelle said yesterday.
"It wasn't the bridge that was at fault, it was the combination of flood waters and the landslide. The video clearly shows the erosion on the downstream side. Luckily, one of our local engineers was in the area, and he stopped traffic immediately."
The village, well known as the set location for the 1989 film version of John B Keane's The Field, has experienced a similar collapse before. Mountain floods and high tides damaged the road between Westport and Killary, now the N59, in 1828 and brought down what was then known as the "Leenaun bridge".
Renowned early 19th-century Scottish engineer Alexander Nimmo, who built many piers and bridges in Connemara, made several attempts to repair Leenane's link; writer Maria Edgeworth recorded in 1833 how three of his structures failed initially.
Owners of vehicles parked on the far side of the bridge before Wednesday's incident had to be ferried across in an inflatable.
Minister for Rural Affairs Éamon Ó Cuív said finances would be made available for a new bridge.
However, Mr Lavelle said a lot of detailed analysis and design work would have to be carried out first. "We will have a one-way bailey structure in place within two weeks. In the meantime, pedestrians will be able to cross by Friday evening."
He said the local authority had an inventory of bridges, which it was constantly checking for any structural defects.